FIELD OF THE INVENTION

This invention relates to a method of stabilizing an aqueous composition comprising an amino acid and a mineral acid more specifically, where said composition is used for on site preparation of a reconstituted modified acid.

BACKGROUND OF THE INVENTION

In the oil & gas industry, stimulation with an acid is performed on a well to increase or restore production. In some instances, a well initially exhibits low permeability, and stimulation is employed to commence production from the reservoir. In other instances, stimulation or remediation is used to further encourage permeability and flow from an already existing well that has become under-productive due to scaling issues or formation depletion. Acidizing is a type of stimulation treatment which is performed above or below the reservoir fracture pressure in an effort to initiate, restore or increase the natural permeability of the reservoir. Acidizing is achieved by pumping acid, predominantly hydrochloric acid, into the well to dissolve typically limestone, dolomite and calcite cement between the acid insoluble sediment grains of the reservoir rocks or to treat scale accumulation. There are three major types of acid applications: matrix acidizing, fracture acidizing, and breakdown acidizing (pumped prior to a fracturing pad or cement operation in order to assist with formation breakdown (reduce fracture pressures, increased feed rates), as well as clean up left over cement in the well bore or perforations. A matrix acid treatment is performed when acid is pumped into the well and into the pores of the reservoir formation below the fracture pressure. In this form of acidization, the acids dissolve the sediments formation and/or mud solids that are inhibiting the permeability of the rock, enlarging the natural pores of the reservoir (wormholing) and stimulating the flow of hydrocarbons to the wellbore for recovery. While matrix acidizing is done at a low enough pressure to keep from fracturing the reservoir rock, fracture acidizing involves pumping acid into the well at a very high pressure, physically fracturing the reservoir rock and etching the permeability inhibitive sediments. This type of acid treatment forms channels or fractures through which the hydrocarbons can flow, in addition to forming a series of wormholes. In some instances, a proppant is introduced into the fluid which assists in propping open the fractures, further enhancing the flow of hydrocarbons into the wellbore. There are many different mineral and organic acids used to perform an acid treatment on wells. The most common type of acid employed on wells to stimulate production is hydrochloric acid (HCI), which is useful in stimulating carbonate reservoirs. Some of the major challenges faced in the oil & gas industry from using hydrochloric acid include the following: extremely high levels of corrosion (which is countered by the addition of 'filming' type corrosion inhibitors that are typically themselves toxic and harmful to humans, the environment and equipment) reactions between acids and various types of metals can vary greatly but softer metals, such as aluminum and magnesium, are very susceptible to major effects causing immediate damage. Hydrochloric acid produces hydrogen chloride gas which is toxic (potentially fatal) and corrosive to skin, eyes and metals. At levels above 50 ppm (parts per million) it can be Immediately Dangerous to Life and Health (IDHL). At levels from 1300-2000 ppm death can occur in 2-3 minutes. The inherent environmental effects (organic sterility, poisoning of wildlife etc.) of acids in the event of an unintended or accidental release on surface or downhole into water aquifers or other sources of water are devastating and can cause significant pH reduction of such and can substantially increase the toxicity and could potentially cause a mass culling of aquatic species and potential poisoning of humans or livestock and wildlife exposed to/or drinking the water. An unintended release at surface can also cause hydrogen chloride gas to be released, potentially endangering human and animal health. This is a common event at large storage sites when tanks split or leak. Typically if near the public, large areas need to be evacuated post event and a comprehensive, expensive to implement, emergency evacuation plan needs to be in place prior to approval of such storage areas. Because of its acidic nature, hydrogen chloride gas is also corrosive, particularly in the presence of moisture. The inability for mineral acids with common corrosion control additives and blends of such to biodegrade naturally results in expensive cleanup-reclamation costs for the operator should an unintended release occur. Moreover, the toxic fumes produced by mineral & some organic acids are harmful to humans/animals and are highly corrosive and/or produce potentially explosive vapours. Transportation and storage requirements for acids are restrictive and taxing. As well, the dangers surrounding exposure by personnel handling the blending of such dangerous products constrict their use/implementation in areas of high risk such as within city limits and environmentally sensitive areas such as offshore.

Another concern is the potential for exposure incidents on locations due to high corrosion levels, even at ambient temperatures, of acids causing potential storage tank failures and/or deployment equipment failures i.e. coiled tubing or high pressure iron failures caused by high corrosion high rates (pitting, cracks, pinholes and major failures). Other concerns include: downhole equipment failures from corrosion causing the operator to have to execute a work-over and replace down hole pumps, tubulars, cables, packers etc.; inconsistent strength or quality level of mineral & organic acids; potential supply issues based on industrial output levels; high levels of corrosion on surface pumping equipment resulting in expensive repair and maintenance levels for operators and service companies; the requirement of specialized equipment that is purpose built to pump acids greatly increasing the capital expenditures of operators and service companies; and the inability to source a finished product locally or very near its end use; transportation and onsite storage difficulties. Typically, acids are produced in industrial areas of countries located some distance from oil & gas producing areas, up to 10 additives can also be required to control various aspects of the acid’s properties adding to complications in the handling and shipping logistics. Having an alternative that requires minimal additives is very advantageous. Extremely high corrosion and reaction rates with temperature increase causes conventional acids to spend/react or "neutralize" prior to achieving the desired effect such as deeply penetrating an oil or gas formation to increase the wormhole or etched "pathway" effectively to allow the petroleum product to flow freely to the wellbore. As an example, hydrochloric acid can be utilized in an attempt to free stuck drill pipe in some situations. Prior to getting to the required depth to dissolve the formation that has caused the pipe/tubing to become stuck many acids spend or neutralize on formation closer to the surface due to increased bottom hole temperatures and greatly increased reaction rate, so it is advantageous to have an alternative that spends or reacts more methodically allowing the debris to be treated with a solution that is still active, allowing the pipe/tubing to be pulled free. When used to treat scaling issues on surface equipment due to water mineral precipitation, conventional acids are exposed to human and mechanical devices as well as expensive equipment causing increased risk and cost for the operator.

When mixed with bases or higher pH fluids, acids will create a large amount of thermal energy (exothermic reaction) causing potential safety concerns and equipment damage, acids typically need to be blended with fresh water (due to their intolerance of highly saline water, causing potential precipitation of minerals) to the desired concentration requiring companies to pre-blend off-site as opposed to blending onsite with sea or produced water thereby increasing costs associated with transportation. Conventional mineral acids used in a pH control situation can cause rapid degradation of certain polymers/additives requiring increased loadings or chemicals to be added to counter these negative effects.

Many offshore areas of operations have very strict regulatory rules regarding the transportation/handling and deployment of acids causing increased liability and costs for the operator. When using an acid to pickle tubing or pipe, very careful attention must be paid to the process due to high levels of corrosion, as temperatures increase, the typical additives used to control corrosion levels in acid systems begin to degrade very quickly (due to the inhibitors "plating out" on the steel or sheering out in high rate applications) causing the acids to become very corrosive and resulting in damage to downhole equipment/tubulars. Conventional acids can be harmful to many elastomers and/or seals found in the oil & gas industry such as those found in blow out preventers (BOP's) /downhole tools/packers/submersible pumps/seals etc. Having to deal with spent acid during the flowback process is also very expensive as these acids typically are still at a low pH and remain toxic and corrosive. It is advantageous to have an acid blend that can be exported to production facilities through pipelines that, once spent or applied, is much higher than that of spent HC1, reducing disposal costs/fees. Also, mineral acids will typically precipitate iron and/or minerals solubilized during the operation as the pH of the spent acid increases causing facility upsets and lost production. It is advantageous to have a strong acid that will hold these solubilized minerals and metals in solution even as pH rises dramatically close to a neutral state, greatly reducing the need to dispose of spent acids and allowing them to be processed and treated in a more economical manner. Acids are used in the performance of many operations in the oil & gas industry and are considered necessary to achieve the desired production of various petroleum wells and associated equipment, maintain their respective systems and aid in certain drilling operational functions (i.e. freeing stuck pipe, filter cake treatments). The associated dangers that come with using mineral acids are expansive and tasking to mitigate through controls whether they are chemically or mechanically engineered. Eliminating or even simply reducing the negative effects of strong acids while maintaining their usefulness is a struggle and risk for the industry. As the public and government demand for the use of less hazardous products increases, companies are looking for alternatives that perform the required function without all or most of the drawbacks associated with the use of conventional acids.

Several operations in the oil industry expose fluids to very high temperatures (some up to and over 200°C / 392°F), the compositions used in these various operations need to withstand high temperatures without losing their overall effectiveness. These compositions must also be capable of being applied in operations over a wide range of temperatures while not or at least minimally affecting or corroding the equipment with which it comes in contact in comparison to a conventional mineral acid of which the corrosion effect at ultra-high temperatures is very difficult and expensive to control. Offshore oil and gas operations are highly regulated due to the environmental concerns which arise from their operations and the potential for spills along with confined work spaces offering little chance of egress in the case of an incident. The complexity of drilling and completing offshore wells is always compounded by both safety issues (exposure to dangerous chemicals as an example) for workers on such offshore oil rigs and production platforms as well as environmental concerns. Many countries bordering the waters where offshore drilling and production is routinely carried out have put into play a number of regulations and operational parameters aimed at minimizing the environmental and human exposure impact. These regulations/procedures include the ban and/or regulation of certain chemicals which may be harmful to marine life and/or the environment. In order to overcome these very restrictive regulations, many oil companies employ very costly containment programs for the handling of certain chemicals, such as acids, which have a wide array of uses in the industry of oil and gas exploration and production. Many of the issues related with offshore oil and gas exploration and production stem from the fact that the conditions under which this is carried out are substantially different than those encountered in the same types of operations carried out onshore, including but not limited to confined spaces, lack of escape routes, very expensive down hole and surface safety and operational equipment compared to onshore requirements Acids conventionally used in various oil and gas operations can be exposed to temperatures in excess of 200°C. At these temperatures, their reactivity and corrosive properties is exponentially increased and as such their economical effectiveness is greatly decreased. Corrosion is one of the major concerns at high temperatures and is difficult and expensive to control with additional chemistry, if it can be controlled at all. In many situations a mechanical procedure must be utilized as opposed to a chemical solution due to temperature constraints modified and synthetic acids developed and currently patented such as those containing main components of urea and hydrochloric acid are aimed at increasing personnel safety, reducing corrosion effects, slowing down the reaction rate and reducing the toxicity of HC1. However, it has been found that at temperatures above 90°C the urea component in a synthetic or modified acid containing such compound tends to ultimately decompose and produce ammonia and carbon dioxide as a by-product of decomposition. The ammonia component will neutralize the acidic component or HC1 and render the product non-reactive or neutral. Additionally there is the risk of wellbore and/or formation damage due to uncontrolled solubilized mineral precipitation due to the increase in pH caused predominantly by the formation of ammonia during the decomposition phase.

Canadian patent application 2,865,855 discloses compositions comprising hydrochloric acid at a concentration between 8 wt% and 28 wt% inclusive and at least one amino acid. The amino acid/hydrochloric acid molar ratio is between 0.2 and 1.5, and sufficient water is present to dissolve the hydrochloric acid and the amino acid. The amino acid may comprise alanine, asparagine, aspartic acid, cysteine, glutamic acid, histidine, leucine, lysine, methionine, proline, serine, threonine or valine or combinations thereof.

US patent application US 20140041690 Al teaches the use of glycine in the making of a synthetic acid that is said to obviate all the drawbacks of strong acids such as hydrochloric acid. The new compound is made by dissolving glycine in water, in a weight ratio of approximately 1:1 to 1:1.5. The description states that the solution is mixed until the glycine is essentially fully dissolved in the water. Once dissolution is complete, hydrogen chloride gas is dissolved in the solution to produce the new compound, which is referred to as hydrogen glycine. Despite the prior art and in light of the substantial problems elicited by the use of acids in oil and gas operations at high temperatures, there still exists a critical need to find an alternative to known synthetic or complexed/modified acids which will remain stable above temperatures of 90 °C while still providing the safety and lower corrosion effects of a modified acid while maintaining strength/performance of a hydrochloric acid. The inventors have surprisingly and unexpectedly found that by combining an amino acid with hydrochloric acid in appropriate ratios one can obtain both a safer alternative to HC1 all the while maintaining the original performance properties of hydrochloric acid and its usefulness in oil and gas operations. It was discovered that preferred compositions of the present invention exhibit stability for operations at elevated temperature (above 90°C and, in some cases, up to 220°C) them useful in the oil and gas industry for all applications where an acid is required and provides operators the ability to treat high and ultra-high temperature completions and maintenance/production operations with a technology that provides a level of safety, technical advantages and low corrosion unavailable in industry until now. Preferred compositions according to the present invention can ideally be used in various oilfield operations, including but not limited to: spearhead breakdown acid, acid fracturing operations, injection-disposal well treatments, high temperature cyclical steam injection (CSS) scale treatments, steam assisted gravity drainage (SAGD) scale treatments, surface and subsurface equipment and pipelines facilities, filter cake removal, tubing pickling, matrix acidizing operations, stimulations, fracturing, soaks, cement squeezes, fluid pH control, stuck pipe operations, and coiled tubing acid washes, soaks and squeezes.

Canadian patent 2,974,757C discloses aqueous synthetic acid compositions for use in oil industry activities, said composition comprising: lysine and hydrogen chloride in a molar ratio ranging from 1:3 to 1:12.5, preferably from more than 1:5 to 1:8.5; it can also further comprise a metal iodide or iodate; an alcohol or derivative thereof. Said composition demonstrates advantageous properties over known synthetic acids at temperatures above 90°C. It is stated that preferred compositions can be used for various oil and gas industry operations. It is also stated that preferred embodiments of said composition providing substantial advantages in matrix acidizing by increasing the effectiveness of wormholing compared to conventional mineral acids such as HC1.

It has been discovered since the introduction of a modified acid comprising lysine and HC1 in a molar ratio ranging from 1:3 to 1:12.5 that, during the shipping of the components in two separate tanks in the hull of a ship (a solution of liquid lysine monohydrochloride in the water tank of a ship and commercial grade HC1 in the acid tank of a ship), there were signs that, under some conditions, the lysine monohydrochloride solution would recrystallize in the tank prior to being blended with the commercial grade HC1. This undermines the value of the modified acid comprising lysine and HC1 if such cannot be reliably shipped to remote location or even to offshore. In order to maximize the volume of modified acid which is being transported by ship, it is desirable that the two components of the modified acid be shipped in separate components. Since there is an acid tank and a water tank on ships capable of transporting acids, and that modified acids cannot be shipped in the water tank, it is thus necessary to optimize the cargo by shipping the acid in the acid tank and the lysine monohydrochloride in an aqueous solution in the water tank of the ship. The lysine monohydrochloride aqueous composition is typically a saturated composition so as to maximize the volume shipped. However, such a saturated composition is metastable and is prone to re-crystallization at temperatures as low as 18°C. This results in an inability to use the lysine monohydrochloride (as a saturated solution of approximately 50 wt.% content) until the contents have been re-dissolved, which leads to substantial delays, especially when ships need to be off-loaded quickly.

In light of this drawback, there is a need to develop a method to stabilize compositions of amino acid salts, such as lysine monohydrochloride, to be shipped in the water tanks of ships. The value of modified acid compositions comprising lysine monohydrochloride has been recently established, hence a method to overcome the above-mentioned drawback would help enhance its reliability and value as a replacement of conventional hydrochloric acid.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided a method to improve and/or ensure the stability of an aqueous composition comprising an amino acid salt such as lysine monohydrochloride where such a composition is close to being saturated or even in a supersaturated state. According to a preferred embodiment of the present invention, said aqueous composition comprising lysine and HC1 is used as a premix in the preparation of a modified acid composition lysine & hydrogen chloride in a molar ratio ranging from 1:2.1 to 1:12.5; preferably, the aqueous synthetic acid composition comprises lysine and hydrogen chloride in a molar ratio ranging from 1 :3 to 1 : 12.5 ; preferably in a molar ratio ranging from 1:3.5 to 1:9, more preferably in a molar ratio ranging from 1:4.5 to 1:8.5, even more preferably in a molar ratio ranging from more than 1:5 to 1:6.5.

It has been surprisingly and unexpectedly discovered that by adding a first acidic component to a saturated or supersaturated aqueous composition comprising an amino acid salt selected from the group consisting of: lysine monohydrochloride, glycine HC1; histidine HC1, arginine HC1, asparagine HC1; and glutamine HC1, one can improve the stability of the composition. According to a preferred embodiment of the present invention, the salts to use are selected from the group consisting of: lysine monohydrochloride, and glycine HC1. The most preferred salt to use is lysine monohydrochloride. Combining a premix composition comprising water, said amino acid salt and said first acidic component with a commercial grade acid such as hydrochloric acid, leads to the generation of a reconstituted modified acid composition. Reconstituted modified acid compositions according to the present invention have been developed for the oil & gas industry and its associated applications, by targeting the problems of corrosion, logistics & handling, human & environmental exposure, reaction rates, toxicity levels, biodegradation tendencies and formation/fluid compatibilities and facility and/or production and water treatment infrastructure compatibilities. It is an object of the present invention to provide an aqueous synthetic acid composition which can be used over a broad range of applications in the oil and gas industry and which exhibit advantageous properties over known compositions.

According to a preferred embodiment of the present invention, there is provided a process to stabilize a near-saturated or supersaturated aqueous lysine monohydrochloride when such is exposed to temperatures below 0°C. It was noted that aqueous solutions of lysine monohydrochloride (as a premix for the preparation of a modified acid comprising HC1 and lysine) are shipped to destination (in the water tank of a ship) prior to mixing this premix with commercial grade hydrochloric acid (such as but not limited to 32 % hydrochloric acid, 37 % hydrochloric acid) would sometimes exhibit some issues of stability. The inventors have surprisingly discovered that by adding up to 1 wt% hydrochloric acid into a saturated or near saturated lysine monohydrochloride aqueous solution, the stability of the lysine monohydrochloride could be enhance the stability of such a solution so that the lysine monohydrochloride would not recrystallize out of solution during the time it was exposed to conditions (such as temperatures below 18°C) which can typically cause the recrystallization of the lysine monohydrochloride.

According to a preferred embodiment of the present invention, there is provided a method to maintain stable a lysine monohydrochloride solution (especially during shipping or long term storage) prior to its combination in a vessel or on the fly with hydrochloric acid to provide a reconstituted modified acid composition for use in oil and gas activities, said composition comprising: - lysine & hydrogen chloride in a molar ratio ranging from 1:2.1 to 1:12.5; preferably, the aqueous synthetic acid composition comprises lysine and hydrogen chloride in a molar ratio ranging from 1 :3 to 1 : 12.5 ; preferably in a molar ratio ranging from 1:3.5 to 1:9, more preferably in a molar ratio ranging from 1:4.5 to 1:8.5, even more preferably in a molar ratio ranging from more than 1:5 to 1:6.5.

According to an aspect of the present invention, there is provided a method to increase the temperature stability of a first blend and a second blend used in the preparation of a reconstituted aqueous composition comprising lysine monohydrochloride, said process comprising the steps of: providing a first vessel and a second vessel; adding to said first vessel a pre-determined amount of water; adding to said first vessel a pre-determined amount of a first acid to said water; and adding a pre-determined amount of lysine monohydrochloride to said first vessel; and mixing the contents of said first vessel until said lysine monohydrochloride is fully dissolved creating said first blend; adding to said second vessel a second pre-determined amount of a second acid; and adding to said second vessel a second pre-determined amount of lysine monohydrochloride; and mixing the contents of the second vessel until said lysine monohydrochloride is fully dissolved creating said second blend; wherein the first blend has a pH of no more than 1 , is stable down to a temperature at least as low as -5°C and said first blend comprising lysine and HC1 in a molar ratio ranging from 1:20 to 1:15 and stable at a temperature of at least as low as -5°C and wherein the second blend has a pH of no less than 2.5, is stable down to a temperature at least as low as - 5°C and said second blend comprising lysine and HC1 in a molar ratio containing an excess of HC1 of up to 0.2 mole. Preferably, said first blend comprising lysine and HC1 in a molar ratio ranging from 1:18 to 1:16.

Preferably, both first and second blends are stable down to a temperature at least as low as -5°C. Also preferably, both first and second blends are stable down to a temperature at least as low as -10°C. More preferably, both first and second blends are stable down to a temperature at least as low as -15°C.

According to a preferred embodiment of the present invention, the acid is selected from the group consisting of: organic acids; mineral acids; and combinations thereof. Preferably, the organic acid is selected from the group consisting of: citric acid; acetic acid; methanesulfonic acid; and oxalic acid. Preferably, the mineral acid is selected from the group consisting of: hydrochloric acid; nitric acid; sulfuric acid; etc. More preferably, the mineral acid is hydrochloric acid.

According to an aspect of the present invention, there is provided a stabilized aqueous composition of lysine monohydrochloride wherein said composition consists of:

- lysine-monohydrochloride in an amount ranging from 30 wt. % to 37.5 wt. %;

- water; and

- an acidic component adapted to stabilize said lysine monohydrochloride; wherein said composition has a pH of no less than 2.5-3.0 and is stable down to a temperature at least as low as -5°C, wherein stable is meant to understand that the lysine-monohydrochloride does not re-crystallize out from the composition. According to a preferred embodiment of the present invention, said lysine-monohydrochloride is present in an amount ranging from 32.5 wt. % to 37 wt. %. More preferably, said lysine-monohydrochloride is present in an amount ranging from 35 wt. % to 36.5 wt. %.

According to an aspect of the present invention, there is provided a method to increase the stability of an aqueous composition comprising an amino acid salt, said process comprising the steps of: providing a saturated aqueous composition of an amino acid salt selected from the group consisting of: lysine monohydrochloride, glycine HC1; histidine HC1, arginine HC1, asparagine HC1; and glutamine HC1; adding an amount of acid to said aqueous composition of amino acid salt to decrease the pH of such composition to a pH of no less than 2.5 to 3, resulting in a stabilized composition comprising said amino acid containing an excess of acid of up to 0.2 mole.

According to an aspect of the present invention, there is provided a method to increase the stability of an aqueous composition comprising an amino acid salt, said process comprising the steps of: providing a vessel; adding a pre-determined amount of water into said vessel; adding a pre-determined amount of an acid to said water; adding said amino acid salt to said vessel; and mixing the blend until said amino acid salt is fully dissolved; wherein the resulting aqueous composition of amino acid salt having a pH of no less than 2.5 to 3, is stable at down to a temperature at least as low as -5°C and said composition comprising lysine and HC1 in a molar ratio containing an excess of acid of up to 0.2 mole. Preferably, the composition is stable down to a temperature at least as low as -10°C. Also preferably, the composition is stable down to a temperature at least as low as -15°C.

According to a preferred embodiment of the present invention, said amino acid salt is selected from the group consisting of: lysine monohydrochloride, glycine HC1; histidine HC1, arginine HC1, asparagine HC1; and glutamine HC1. Preferably, said amino acid is selected from the group consisting of: lysine monohydrochloride, and glycine HC1.

According to an aspect of the present invention, there is provided a reconstituted lysine-HCl- containing modified acid composition for use in the oil industry to perform an activity selected from the group consisting of: stimulate formations; assist in reducing breakdown pressures during downhole pumping operations; treat wellbore filter cake post drilling operations; assist in freeing stuck pipe; descale pipelines and/or production wells; increase injectivity of injection wells; lower the pH of a fluid; remove undesirable scale on a surface selected from the group consisting of: equipment, wells and related equipment and facilities; fracture wells; complete matrix stimulations; conduct annular and bullhead squeezes & soaks; pickle tubing, pipe and/or coiled tubing; increase effective permeability of formations; reduce or remove wellbore damage; clean perforations; and solubilize limestone, dolomite, calcite and combinations thereof; wherein said composition is prepared by admixing a first blend and a second blend and said composition comprises lysine and HC1 in a molar ratio ranging from 1:2.1 to 1:12.5, and wherein said first blend has a pH of no more than 1 , is stable down to a temperature at least as low as -5°C and said first blend comprising lysine and HC1 in a molar ratio ranging from 1:20 to 1:15; and wherein said second blend has a pH of no less than 2.5, is stable down to a temperature at least as low as -5°C and said second blend comprising lysine and HC1 in a molar ratio containing an excess of HC1 of up to 0.2 mole. Preferably, said reconstituted lysine-HCl-containing modified acid composition comprises lysine and HC1 in a molar ratio ranging from 1:4.5 to 1:8.5.

According to an aspect of the present invention, there is provided a use of a stabilized aqueous composition of lysine monohydrochloride for the preparation of a modified acid composition, wherein said stabilized aqueous composition of lysine monohydrochloride consists of:

- lysine-monohydrochloride in an amount ranging from 30 wt. % to 37.5 wt. %;

- water; and

- an acidic component adapted to stabilize said lysine monohydrochloride; wherein said stabilized aqueous composition has a pH of no less than 2.5 - 3.0 and is stable down to a temperature at least as low as -5°C, wherein stable is meant to understand that the lysine-monohydrochloride does not re-crystallize out from the composition; and wherein said modified acid composition has a pH below 1 and comprises lysine and HC1 in a molar ratio ranging from 1:2.1 to 1:12.5.

According to an aspect of the present invention, there is provided a use of a stabilized aqueous composition of an amino acid salt for the preparation of a modified acid composition, wherein said stabilized aqueous composition of lysine monohydrochloride consists of:

- an amino acid salt in an amount ranging from 30 wt. % to 37.5 wt. %;

- water; and

- an acidic component adapted to stabilize said amino acid salt; wherein said stabilized aqueous composition has a pH of no less than 2.5-3.0 and is stable down to a temperature at least as low as -5°C, wherein stable is meant to understand that the amino acid salt does not re-crystallize out from the composition; and wherein said modified acid composition has a pH below 1 and comprises said amino acid and HC1 in a molar ratio ranging from 1:2.1 to 1:12.5.

According to yet another aspect of the present invention, there is provided a use of a stabilized aqueous composition of an amino acid salt for the preparation of a modified acid composition, wherein said stabilized aqueous composition of amino acid salt consists of:

- an amino acid salt in an amount ranging from 30 wt. % to 37.5 wt. %;

- water; and

- a first acidic component adapted to stabilize said amino acid salt; wherein said stabilized aqueous composition has a pH of no less than 2.5 -3.0 and is stable down to a temperature at least as low as -5°C, wherein stable is meant to understand that the amino acid salt does not re-crystallize out from the composition; and wherein said modified acid composition has a pH below 1 and comprises said amino acid and a second acidic component in a molar ratio ranging from 1:2.1 to 1:12.5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles of the present invention. These examples are provided for the purposes of explanation, and not limitation, of those principles and of the invention.

Lysine and HC1 are the main components in terms of volume and weight percent of a reconstituted aqueous acid composition according to a preferred embodiment of the present invention obtained upon blending of commercial grade hydrochloric acid and lysine monohydrochloride, and as an amino acid it contains at least one amino group, -NH2, and one carboxyl group, -COOH. When added to hydrochloric acid a Lewis acid/base adduct is formed where the primary amino group acts as a Lewis base and the proton of the Hydrochloric acid as Lewis acid. The formed adduct greatly reduces the hazardous effects of the hydrochloric acid on its own, such as the fuming effect, the hygroscopicity, and the highly corrosive nature The excess nitrogen can also act as a corrosion inhibitor at higher temperatures. Lysine & hydrogen chloride are present in a molar ratio ranging from 1:3 to 1:12.5; preferably in a molar ratio ranging from 1:4.5 to 1:9, and more preferably in a molar ratio ranging from more than 1:5 to 1:8.5. Lysine mo nohydrochloride can be purchased as a white powder. It has a pH ranging from 5.0-6 at 91.3g/l at 25°C (77 °F); melting point/range: 263 °C (505 °F); it has a density of 1.28 g/cm ³ at 20 °C (68 °F); and can dissolve 91.3 g/1 of water at 20 °C (68 °F).

Example #1: Preparation of various Lysine-HCl premixes according to preferred embodiments of the present invention

Various premixes containing lysine monohydrochloride according to preferred embodiments of the present invention were prepared according to the following process. According to a preferred embodiment of the present invention, the process comprises the following steps:

1. add the water amount as listed in Table 1 or 2 into the vessel (reactor);

2. start reactor circulation (note: the next step is highly exothermic; fumes can be evolved during this process. The usage of a water scrubber is recommended);

4. slowly add the required volume of hydrochloric acid according to Table 1 into the reactor;

5. in a controlled manner, slowly introduce lysine monohydrochloride into the reactor (note: if lysine monohydrochloride is added too rapidly, formation of large solid masses can occur which can plug equipment and solubilize slowly due to the reduced available surface area); and

6. circulate until complete mixing has occurred (at least one complete volume turnover) (note: flush fluid lines with water to prevent lysine from crystallizing in the tubing or pumps).

Preferably, the resulting premix can then be shipped to the destination where they are intended to be used in the preparation of a reconstituted modified acid composition. Table #1 provides a list of components and amounts associated with each used in the preparation of various pre-mixes according to preferred embodiments of the present invention.

Table 1: Volume of Products Required to make 1000L (1125 kg) of Premix #1, #2. #3 and #4 Table 2: Weight of Products Required to make 8891 (1000 kg) of Premix #1, #2, #3 and #4

Premixes #1, #2 and #3 have a hydrochloric acid content of approximately 0.925 %, while the premix #4 has a lower hydrochloric acid content of approximately 0.33 wt. %. The composition labelled Premix #2 was used in further testing. The density of said premix #2 was measured to be 1.144 kg/m ³ while the pH @ ambient temperature was determined to be 2.75. Premix #4 has a pH of approximately 3.0.

According to a preferred embodiment of the present invention, it is possible to adjust the lysine - HC1 ratio in the reconstituted lysine-HCl-containing modified acid composition depending on the intended application and the desired solubilizing ability. By increasing the ratio of the HC1 component, the solubilizing ability will increase while still providing certain health, safety, environmental and operational advantages over hydrochloric acid. It is preferable to add the lysine at a molar ratio less than 1 : 1 to the moles of hydrochloric acid (or any acid). Tests have shown than even adding lysine to HC1 in a molar ratio of around 1:2 would neutralize the hydrochloric acid to the point of substantially or almost completely removing all of its acidic character. Preferably, the composition according to the present invention comprises at most 1 mole of lysine per 3.0 moles of HC1. The lysine-hydrochloride also allows for a reduced rate of reaction when in the presence of carbonate-based materials. This again is due to the stronger molecular bonds associated over what hydrochloric acid traditionally displays. Further, since the composition according to the present invention is mainly comprised of lysine (which is naturally biodegradable), the product testing has shown that the lysine hydrochloride will maintain the same biodegradability function, something that hydrochloric acid will not on its own. Alcohols and derivatives thereof, such as alkyne alcohols and derivatives and preferably propargyl alcohol and derivatives thereof can be used as corrosion inhibitors. For offshore uses, to make a modified acid comprising lysine and HC1 in a molar ratio ranging from 1:3 to 1:12.5; preferably in a molar ratio ranging from 1:4.5 to 1:9, and more preferably in a molar ratio ranging from more than 1:5 to 1:8.5, the HC1 is transported in an acid-resistant tank inside a ship and the lysine-HCl (1:1 molar ratio) is transported in the water tank portion of the vessel. Once arrived on site, the two portions (HC1 and lysine-HCl (in a 1:1 molar ratio) are blended to the desired ratio of HCldysine. According to a preferred embodiment the modified acid can be blended in batches or on the fly.

Currently, to transport a modified acid comprising lysine and HC1 in a molar ratio ranging from 1:3 to 1:12.5 one can only use the acid tank portion of a ship. This means that basically half of the ship’s potential storage room is left unused. To overcome this logistical barrier, the inventors have developed a safe pre-mix to be combined with commercial grade acids such as hydrochloric acid, said pre-mix are intended on being shipped inside the water tank (previously mentioned) where the pH and other characteristics are suitable and safe and non-corrosive for the water tank for extended exposure durations of time (such as several weeks).

Typically, ship tanks which are used to carry chemicals are coated with acid-resistant coatings. One widely used type of coating is epoxy-based. Appropriate epoxy-cased coatings will protect both the steel of the from being affected by the contents and the contents from being contaminated. One such epoxybased coating used for such purpose is Hempadur® 35760. This coating provides very high corrosion protection properties and excellent chemical resistance and is especially well-suited for new and old storage tanks containing oils, fuels, bio fuels and a wide range of chemicals. Another epoxy-based coating is Hempadur® 85671, an epoxy phenolic resistant to very aggressive cargos, such as acids.

Another type of coating is Intershield® 300HS which is described as a high solids, abrasion resistant, aluminum pure epoxy coating capable of providing excellent long term anti-corrosive protection and low temperature capability. It comes as a universal primer which can be applied directly to mechanically prepared shop primer or suitably prepared bare steel.

Compatibility testing of Premix #2 on coupons coated in Intershield® 300HS and Hempadur® 85671 epoxy was carried out in order to determine the feasibility of transporting acidic precursor (premixes as discussed above) compositions comprising lysine monohydrochloride and an excess of acid component where the pH is above 2.5. Once the acidic precursor compositions reaches its destination, according to a preferred embodiment of the present invention, an operator may blend such composition with commercial grade Hydrochloric acid on-the-fly or in batches depending on the situation. According to a preferred embodiment of the present invention such blending is intended on yielding a composition comprising a lysine and HC1 in a molar ratio ranging from 1:3 to 1:12.5; preferably in a molar ratio ranging from 1:4.5 to 1:9, and more preferably in a molar ratio ranging from more than 1:5 to 1:8.5. Preferably, the composition comprises lysine and HC1 in a molar ratio ranging from 1:4.5 to 1:8.5.

Compatibility testing

The tests were executed on 316 stainless steel coupons coated in Intershield® 300HS and Hempadur® 85671 epoxy submerged in Premix #2 blend at ambient temperature and 55 °C (131 °F), for 7 and 14 days. After the test period, the integrity of the epoxy resin was observed to not be compromised. Compatibility testing between Premix #2 and the Intershield® 300HS epoxy-coated coupons had shown minimal mass change of < 0.12 % and the Hempadur® 85671 epoxy-coated coupons had shown minimal mass change of < 0.15 % after 14 days. Full testing results are reported in Tables 3 and 4.

Compatibility Testing with Intershield- 300HS Epoxy-coated Coupons

To prepare the coupons for corrosion testing, the Intershield® 300HS epoxy was prepared by mixing 2.5 parts of A with 1 part of B as per manufacturers specifications. The 316SS coupons were then coated in the epoxy and hung to allow excess to drip off. The coupons were then placed into an oven at 45 °C (113 °F) for 1 hour and then removed to apply a second layer of epoxy coat to cover any areas that may have had a thin layer or exposed corners. The coupon was then hung to dry overnight in an oven set to 45 °C (113 °F) before the coupons were weighed. A photo of each coupon was taken to document the initial appearance of the surface.

Procedure:

To determine the corrosion properties of Premix #2, the blend was evaluated at ambient temperature, approximately 20 °C (68 °F) and at 50 °C (122 °F) on the epoxy-coated coupons. At ambient temperature, the tests were executed on a bench top, while at 50 °C (122 °F), tests were executed in a heated water bath. After the exposure time, the coupons were removed, washed with warm water and soap, isopropanol, and dried. The weights of the coated coupons were recorded. A photo of each coupon was taken to document the appearance of the surface after the exposure to the Premix #2.

Results:

Test results of the compatibility experiment with Intershield® 300HS epoxy-coated coupons are shown in Table 3. Table 3: Corrosion results of Premix #2 with Intershield® 300HS epoxy-coated coupons

Compatibility Testing with Hempadur- 85671 Epoxy-coated Coupons

Procedure:

To prepare the coupons for corrosion testing, the Hempadur® 85671 epoxy was prepared by mixing 8.9 parts of A with 1.1 parts of B as per manufacturers specifications. The 316SS coupons were then coated in the epoxy and hung to allow excess to drip off. The coupons were then placed into an oven at 45 °C (113 °F) for 1 hour and then removed to apply a second layer of epoxy coat to cover any areas that may have had a thin layer or exposed corners. The coupon was then hung to dry overnight in an oven set to 45 °C (113 °F) before the coupons were weighed. A photo of each coupon was taken to document the initial appearance of the surface.

Procedure:

To determine the corrosion properties of Premix #2 the blend was evaluated at ambient temperature, approximately 20 °C (68 °F) and at 55 °C (131 °F) on the epoxy-coated coupons. At ambient temperature, the tests were executed on a bench top, while at 55°C (131°F), tests were executed in a heated water bath. After the exposure time, the coupons were removed, washed with warm water and soap, iso-propanol, and dried. The weights of the coated coupons were recorded. A photo of each coupon was taken to document the appearance of the surface after the exposure to the Premix #2.

Results: Test results of the compatibility experiment with Hempadur® 85671 epoxy-coated coupons are shown in Table 4.

Table 4: Corrosion results of Premix #2 with Hempadur® 85671 epoxy-coated coupons

From a review of the results, the conclusion is clear that compositions according to the present invention such as preferred embodiment Pre-mix #2 is much less corrosive to epoxy-coated coupons than conventional 15% HC1.

According to another aspect of the present invention, a different approach was taken to achieve stable pre-mix blends which have stability at low temperatures.

According to a preferred embodiment of the present invention, a pre-mix (or pre -blend) of both the acid and the lysine component were prepared so as to have two temperature stable pre -blends. The transport of those two pre-blends to a site where they will be combined to generate a reconstituted modified acid is made less troublesome because of their enhanced temperature stability.

According to a preferred embodiment of the present invention, three different pairs of pre-mix (or pre -blend) containing a major acid component and a major amino acid (lysine) component were prepared. These pre-mix blends are summarized in table 5 below. Pre-mix blends A and B and pre-mix blends C and D when combined yield a reconstituted modified acid composition of molar ratio of HC1: lysine of 4.1 : 1 (at a 90% concentration). Pre-mix blends E and F when combined yield a reconstituted modified acid composition of molar ratio of HCklysine of 4.1 : 1 (at a 100% concentration). Tables 6 and 7 provide a more detailed breakdown of one the pairs of pre-mix blends, pair A and B.

Table 5: Various pre-mix blends according to preferred embodiment of the present invention

Table 6: Components and corresponding amounts of pre-mix blend A according to preferred embodiment of the present invention

Table 7: Components and corresponding amounts of pre-mix blend B according to preferred embodiment of the present invention

Quality Control Testing

Various blends according to preferred embodiments of the present invention were prepared and various characteristics were measured and compared to the reconstituted modified acid. Table 8 lists the specific gravity measured following SOP-003, the refractive index measured following SOP-018, the pH measured following SOP-OOl, and the acidity measured following SOP-004.

Table 8: Various parameters of reconstituted modified acid prepared using pre-mix compositions according to the present invention

Stability Testing

Low temperature stability testing was conducted at -10 °C (14 °F) for a duration of 14 days on 3 pairs of pre-mix blends that, upon mixing, create a reconstituted lysine-HCl modified acid (present in a 1:4.1 molar ratio) at a 100 % concentration.

Pre-mix pair A and B made with 32 % HC1 were combined upon mixing to create a reconstituted lysine-HCl modified acid equivalent (present in a 1:4.1 molar ratio) at a 90 % concentration.

Pre-mix pair C and D made with 36 % HC1 were combined upon mixing create a reconstituted lysine-HCl modified acid equivalent (present in a 1:4.1 molar ratio) at a 90 % concentration.

Pre-mix pair E and F made with 36 % HC1 were combined upon mixing create a reconstituted lysine-HCl modified acid equivalent (present in a 1:4.1 molar ratio) at a 100 % concentration.

The stability testing was tested on the blends listed in Table 1. The testing was executed at -10°C (14°F) for a duration of 14 days. 50 mF of each blend was filled into a plastic bottle, caps were sealed and the bottles were placed into the water bath for the duration of the testing. After the testing period, the solutions were filtered through a 100 mesh screen and a photo of the screen was taken.

No crystallization was observed in any of the 3 pairs of pre-blends (A and C; C and D; and E and F).

Corrosion testing

Corrosion tests were performed utilizing a 90% concentration of a lysine-HCl modified acid equivalent (present in a 1:4.1 molar ratio) blend on E80 corrosion coupons at a temperature of 121 °C (250 °F). The corrosion tests were also performed using a 90 % concentration of a reconstituted lysine-HCl modified acid equivalent (present in a 1:4.1 molar ratio) (from pair A and B and pair C and D) for a testing period of 6 hours. Full corrosion testing results are found in Table 7.

Corrosion tests were executed in a high pressure/high temperature Teflon lined cell. For each experiment a L80 steel coupon was washed with acetone, air dried, and weighed, before being suspended in the test fluid and then the cell was pressurized with nitrogen. Each cell was placed in a preheated oven for the specified test duration, plus an additional 30 minutes of heat up time for tests less than 24 hours in duration. After the exposure period, each cell was depressurized, and the coupon was removed, washed with water, followed by an acetone wash, air dried, and then weighed. The corrosion rate was determined from the weight loss, and the pitting index was evaluated visually at 40X magnification, and a photo of the coupon surface at 10X and 40X magnification was taken.

Table 7: Corrosion testing of various fluids at 120"C under a pressure of 400 psi for a duration of 6 hours

NB: C1-1A refers to potassium iodide; Cl-5 refers to a proprietary corrosion inhibitor package comprising a terpene; a cinnamaldehyde or a derivative thereof; at least one amphoteric surfactant; and a solvent.

The pitting index indicates: No pits. The surface is the same as for the original un the pitting index reported in: Finsgar, M.; Jackson, J. Corrosion Science, 2014, 8

Preparation of batch of a reconstituted modified acid comprising a 1:4.1 molar ratio of lysine to HC1

This composition is obtained through the following mixing ratio: 370 ml of Premix (saturated composition of lysine monohydrochloride in water and acid) solution + 300 ml 22 Baume HC1; which leads to the following ratio: 1 mol Lysine monohydrochloride to 4.1 mol HC1. The composition of Example 3 has an amber liquid appearance. Its salinity is 48%. Its freezing point is minus 45°C and boiling point above 100°C. Its pH is below 1. The reconstituted modified acid composition (1 mol Lysine monohydrochloride to 4.1 mol HC1) was also tested for skin corrosiveness and deemed non-corrosive to the skin. Oral toxicity was calculated using the LD50 rat model and deemed to be of low oral toxicity. It is considered readily biodegradable and offers a lower bioaccumulative potential when compared to 15% Hydrochloric acid .

According to a preferred embodiment of the present invention, when preparing a reconstituted modified acid using pre-blends as starting compositions, one can use: a first blend comprising water / 80 % of the total amount of lysine used in the modified acid and 36 % HC1 (to yield a 0.99 % active HC1); and a second blend comprising 36 % HC1 / 20 % of the total amount of lysine used in the modified acid.

The combination of said first and second blends will yield a reconstituted lysine-HCl modified acid (1:4.1 molar ratio) (at full, undiluted concentration).

Canadian Patent 2,974,757 discloses the dermal safety data for modified acid composition comprising lysine and HC1 in various molar ratios. The patent also discloses the scale solubility and dissolution power of such compositions, the disclosure in CA 2,974,757 is hereby incorporated in its entirety. These compositions are similar to the reconstituted lysine-HCl-containing modified acid composition discussed herein. The teachings of Canadian Patent 2,974,757 are hereby incorporated by reference.

Stability Testing of a reconstituted modified acid composition comprising lysine and HC1

Testing was carried out using pressurized ageing cell with Teflon liner in order to assess the stability of various lysine-HCl compositions obtained from the mixing of saturated or supersaturated aqueous lysine monohydrochloride compositions with commercial grade Hydrochloric acid. The tests were conducted at a pressure of 300 psi (denoted by an asterisk) and at 400 psi established that lysine-HCl compositions obtained mixing of saturated or supersaturated aqueous lysine monohydrochloride compositions with commercial grade Hydrochloric acid are stable when exposed to temperatures above 200°C.

Scale solubility

The power of a modified acid composition comprising lysine and HC1 obtained from the mixing of a premix comprising a saturated or near saturated aqueous lysine monohydrochloride composition with commercial grade Hydrochloric acid to dissolve scale was assessed. It was determined that a modified acid composition obtained from the mixing of saturated or supersaturated aqueous lysine monohydrochloride compositions with commercial grade hydrochloric acid provides an excellent solubilizing ability when dealing with various oilfield scales. Its solubilizing ability is comparable to the solubility of most many mineral and organic acid packages typically utilized.

Elastomer compatibility

When common sealing elements used in the oil and gas industry come in contact with acid compositions they tend to degrade or at least show sign of damage. A number of sealing elements common to activities in this industry were exposed to a composition according to a preferred embodiment of the present invention to evaluate the impact of the latter on their integrity. More specifically, the hardening and drying and the loss of mechanical integrity of sealing elements can have substantial consequences on the efficiency of certain processes as breakdowns require the replacement of defective sealing elements. Testing was carried out to assess the impact of the exposure of composition of Example 2 to various elastomers and was found to be stable for the period of time tested.

According to a preferred embodiment of the present invention, the resulting acidic composition will, upon proper use, results in a very low corrosion rate on oil and gas industry tubulars and equipment compared to mineral acids, such as hydrochloric acid.

According to a preferred embodiment of the present invention, the reconstituted lysine-HCl- containing modified acid composition can be used in the oil industry and is biodegradable.

According to a preferred embodiment of the present invention, the reconstituted lysine-HCl- containing modified acid composition can be used in the oil industry as it possesses a controlled, more methodical spending (reacting) nature that is near linear as temperature increases, low- fuming/vapor pressure, low- toxicity, and has a highly controlled manufacturing process ensuring consistent end product strength and quality.

According to another preferred embodiment of the present invention, there is provided an aqueous modified acid composition (referred to as the reconstituted aqueous modified acid composition) for use in the oil industry which has a pH below 1. According to another preferred embodiment of the present invention, there is provided an aqueous synthetic acid composition for use in the oil industry which will keep iron particles and solubilized carbonate in solution even as the pH rises to a level > 4 pH. According to another preferred embodiment of the present invention, there is provided an aqueous synthetic acid composition for use in the oil industry which will provide a thermal stability at temperatures above 100°C. According to another preferred embodiment of the present invention, there is provided a synthetic acid composition for use in the oil industry which will provide corrosion protection at an acceptable oilfield limit when said composition is in contact with metal components and is at temperatures ranging from 100°C to 220°C. According to a preferred embodiment of the present invention, there is provided a modified acid composition for use in the oil industry which has minimal exothermic reactivity upon dilution or during the reaction process.

Preferably, the reconstituted aqueous modified acid composition for use in the oil industry is compatible with existing industry acid additives. According to another preferred embodiment of the present invention, there is provided an aqueous synthetic acid composition for use in the oil industry which has higher salinity tolerance. A tolerance for high salinity fluids, or brines, is desirable for onshore and offshore acid applications. Conventional acids are normally blended with fresh water and additives, typically far offsite, and then transported to the area of treatment as a finished blend. It is advantageous to have an alternative that can be transported as a concentrate safely to the treatment area, then blended with a saline produced water or sea water greatly reducing the logistics requirement. A conventional acid system can precipitate salts/minerals heavily if blended with fluids of an excessive saline level resulting in formation plugging or ancillary damage, inhibiting production and substantially increasing costs. Brines are also typically present in formations, thus having an acid system that has a high tolerance for brines greatly reduces the potential for formation damage or emulsions forming down-hole during or after product placement/spending (reaction) occurs. According to another aspect of the present invention, there is provided an aqueous modified acid composition for use in the oil industry which is immediately reactive upon contact/application. According to another aspect of the present invention, there is provided an aqueous modified acid composition for use in the oil industry which results in less unintended near wellbore erosion or face dissolution due to a more controlled reaction rate. This, in turn, results in deeper formation penetration, increased permeability, and reduces the potential for zonal communication during a typical 'open hole' mechanical isolation application treatment. As a highly reactive acid, such as hydrochloric acid, is deployed into a well that has open hole packers for isolation (without casing) there is a potential to cause a loss of near-wellbore compressive strength resulting in communication between zones or sections of interest as well as potential sand production, and fines migration. It is advantageous to have an alternative that will react with a much more controlled rate or speed, thus greatly reducing the potential for zonal communication and the above potential negative side effects of traditional acid systems. According to a preferred embodiment of the present invention, there is provided an aqueous synthetic acid composition for use in the oil industry which provides a controlled and comprehensive reaction rate throughout a broad range of temperatures up to 220°C. Upon reconstitution, additional chemical may be added to the reconstituted modified acid compositions prior to use. These include but are not limited to corrosion inhibitors, scale inhibitors, demulsifiers, reducing agents and/or chelants. For example, non-surface active substituted ammonium containing amino acid derivatives may be used as environmentally friendly corrosion inhibitors that effectively protect various tools employed in oilfield operations by surface treating these tools.

According to a preferred embodiment of the present invention, the corrosion inhibitor is typically provided in liquid form and is mixed with the other components of the treatment fluid at the surface and then introduced into the formation. The corrosion inhibitor package can be present in an amount ranging from 0.1 wt % to about 5 wt. %, more preferably 0.2 wt.% to 3 wt.% of the total weight of the composition used in the treatment operations. Preferably, the corrosion inhibitor used with the fluids of the present disclosure includes an alkyl, alkenyl, alicyclic or aromatic substituted aliphatic ketone, which includes alkenyl phenones, or an aliphatic or aromatic aldehyde, which includes alpha, or beta-unsaturated aldehydes, or a combination of these. Alkyl, alicyclic or aromatic phenone and aromatic aldehyde compounds may also be used in certain applications. According to another preferred embodiment, other unsaturated ketones or unsaturated aldehydes are used. According to another preferred embodiment, alkynol phenone, aromatic and acetylenic alcohols and quaternary ammonia compounds, and mixtures of these are used. According to another preferred embodiment, a solvent is present. Preferably, the solvent is an alcohol is selected from the group comprising, but not limited to: methanol, ethanol, isopropanol, butanol or the like. Other additives may also be used according to other preferred embodiments of the present invention.

According to a preferred embodiment of the present invention, alcohols and derivatives thereof, such as alkyne alcohols and derivatives and preferably propargyl alcohol and derivatives thereof can be used as corrosion inhibitors with the reconstituted modified acid compositions. Propargyl alcohol itself is traditionally used as a corrosion inhibitor which works well at low concentrations. It is however a very toxic/flammable chemical to handle as a concentrate, so care must be taken when exposed to the concentrate. In some cases, it is preferred to use 2-Propyn-l-ol, complexed with methyloxirane, as this is a much safer derivative to handle. Basocorr® PP is an example of such a compound. In preferred embodiments of the present invention, 2- Propyn-l-ol, complexed with methyloxirane is present in an amount ranging from 20% to 55% by volume of the total volume of the corrosion inhibition package. According to another preferred embodiment of the present invention, terpenes can be used to achieve desirable corrosion inhibition results. Preferably, the terpene is selected from the group consisting of: monoterpenes (acyclic); monocyclic terpenes; and beta-ionone. Exemplary but non-limiting compounds of some of the previously listed terpene sub-classes comprise: for monoterpenes: citral (mixture of geranial and neral); citronellal; geraniol; and ocimene; for monocyclic terpenes: alpha- terpinene; carvone; p- cymene. More preferably, the terpenes are selected from the group consisting of: citral; ionone; ocimene; and cymene.

According to a preferred embodiment of the present invention, the corrosion inhibition package used with the reconstituted modified acid compositions comprises a surfactant which is environmentally friendly. More preferably, the surfactant is capable of withstanding exposure to temperatures of up to least 220°C for a duration of 2 to 4 hours in a closed environment without undergoing degradation. Preferably, there may be at least one amphoteric surfactant selected from the group consisting of: a sultaine surfactant; a betaine surfactant; and combinations thereof. More preferably, the sultaine surfactant and betaine surfactant are selected from the group consisting of: an amido betaine surfactant; an amido sultaine surfactant; and combinations thereof. Yet even more preferably, the amido betaine surfactant and is selected from the group consisting of: an amido betaine comprising a hydrophobic tail from Cs to Ci6. Most preferably, the amido betaine comprising a hydrophobic tail from Cs to Ci6 is cocamidobetaine.

According to a preferred embodiment of the present invention, the corrosion inhibition package further comprises an anionic surfactant. Preferably, the anionic surfactant is a carboxylic surfactant. More preferably, the carboxylic surfactant is a dicarboxylic surfactant. Even more preferably, the dicarboxylic surfactant comprises a hydrophobic tail ranging from Cs to Ci6. Most preferably, the dicarboxylic surfactant is sodium lauriminodipropionate Most preferred are embodiments of a corrosion inhibition package comprising cocamidopropyl betaine and B-Alanine, N-(2-carboxyethyl)-N-dodecyl-, sodium salt (1:1). According to a preferred embodiment of the present invention, when preparing an acidic composition comprising a corrosion inhibition package, metal iodides or iodates such as potassium iodide, sodium iodide, cuprous iodide and lithium iodide can be added as corrosion inhibitor intensifier. The iodide or iodate is preferably present in a weight/volume percentage ranging from 0.1 to 1.5%, more preferably from 0.25 to 1.25%, yet even more preferably 1% by weight/volume of the acidic composition. Most preferably, the iodide used is potassium iodide. According to a preferred embodiment of the present invention, the corrosion package comprises: 2-Propyn-l-ol, compd. with methyloxirane; B-Alanine, N-(2-carboxyethyl)- N- dodecyl-, sodium salt (1:1); cocamidopropyl betaine; 3,7-Dimethyl-2,6-octadienal (Citral); and isopropanol. More preferably, the composition comprises 38.5% of 2-Propyn-l-ol, compd. with methyloxirane; 5% of B-Alanine, N-(2-carboxyethyl)-N-dodecyl-, sodium salt (1:1); 5% of cocamidopropyl betaine; 20% of 3,7-Dimethyl-2,6-octadienal (Citral); and 31.5% of isopropanol (all percentages are volume percentages).

According to a preferred embodiment of the present invention, the compositions may further comprise a chelating agent to control and remove undesirable metal ions. Preferably one of the following type of chelating agents can be employed with the reconstituted modified acid compositions according to the present invention: polycarboxylic acids (including aminocarboxylic acids and polyaminopolycarboxylic acids) and phosphonates. The non-surface active substituted ammonium containing amino acid derivatives may act as chelating agents when present in the reconstituted modified acid compositions in amount of from about 0.05% to about 10% or from about 1 wt % to about 5 wt %, based on total weight percent of the reconstituted modified acid compositions.

According to a preferred embodiment of the present invention, the reconstituted lysine-HCl- containing modified acid composition can be used in a molar ratio ranging from 1 : 3.5 to 1 : 12.5 for injection into an oil or gas well to perform a treatment with said composition; recovering the spent acid from the well; and sending the spent acid to a plant.

According to a preferred embodiment of the present invention, the reconstituted lysine-HCl- containing modified acid composition can be used to overcome many of the drawbacks found in the use of compositions of the prior art related to the oil & gas industry.

According to a preferred embodiment of the present invention, the reconstituted lysine-HCl- containing modified acid composition can be used in a method of matrix acidizing a hydrocarbon- containing dolomite formation, said method comprising: - providing a composition comprising a HC1 and lysine mixture and water; wherein the molar ratio between the HC1 and the lysine ranges from 4.5:1 to 8.5:1, - injecting said composition downhole into said formation at a pressure below the fracking pressure of the formation; and - allowing a sufficient period of time for the composition to contact said formation to create wormholes in said formation.

According to a preferred embodiment of the present invention, the reconstituted lysine-HCl- containing modified acid composition can be used in the oil industry to perform an activity selected from the group consisting of: stimulate formations; assist in reducing breakdown pressures during downhole pumping operations; treat wellbore filter cake post drilling operations; assist in freeing stuck pipe; descale pipelines and/or production wells; increase injectivity of injection wells; lower the pH of a fluid; remove undesirable scale on a surface selected from the group consisting of: equipment, wells and related equipment and facilities; fracture wells; complete matrix stimulations; conduct annular and bullhead squeezes & soaks; pickle tubing, pipe and/or coiled tubing; increase effective permeability of formations; reduce or remove wellbore damage; clean perforations; and solubilize limestone, dolomite, calcite and combinations thereof; said composition comprising lysine and HC1 in a molar ratio ranging from 1:2.1 to 1:12.5. Preferably, the composition comprises lysine and HC1 in a molar ratio ranging from 1:4.5 to 1:8.5.

Uses of a reconstituted modified acid composition comprising lysine and HC1 according to a preferred embodiment of the present invention

The uses (or applications) of the reconstituted modified acid composition comprising lysine and HC1 according to the present invention upon dilution thereof ranging from approximately 1 to 90% dilution are listed below in Table 8 and include, but are not limited to: injection/disposal treatments; matrix acid squeezes, soaks or bullheads; acid fracturing, acid washes; fracturing spearheads (breakdowns); pipeline scale treatments, cement breakdowns or perforation cleaning; pH control; and de-scaling applications, high temperature (up to 180°C) cyclical steam scale treatments and steam assisted gravity drainage (SAGD) scale treatments (up to 220°C) As would be understood by the person skilled in the art, the methods of use generally comprise the following steps: providing a composition according to a preferred embodiment of the present; exposing a surface (such as a metal surface) to the acid composition; allowing the acid composition a sufficient period of time to act upon said surface; and optionally, removing the acid composition when the exposure time has been determined to be sufficient for the operation to be complete or sufficiently complete. Another method of use comprises: injecting the acid composition into a well and allowing sufficient time for the acid composition to perform its desired function. Yet another method according to the present invention comprises the steps of: providing a composition according to a preferred embodiment of the present; injecting the composition into a well; an optional step of dilution of the acid composition can be performed if deemed necessary prior to injection downhole; monitoring the various injection parameters to ensure that the pressure and rate of injection are below frac pressures and below conventional injection rates used for conventional acids such as hydrochloric acid ; allowing sufficient period of time to act upon said formation to obtain the desired wormholing effect; and optionally, removing the acid composition when the exposure time has been determined to be sufficient for the operation to be complete or sufficiently complete.

Yet another method of use comprises: exposing the acid composition to a body of fluid (typically water) requiring a decrease in the pH and allowing sufficient exposure time for the acid composition to lower the pH to the desired level. Table 8 - Applications for which compositions according to the present invention can be used as well as proposed dilution ranges

The main advantages of the use of the synthetic acid composition included: the reduction of the total loads of acid, and the required number of tanks by delivering concentrated product to location and diluting with fluids available on location (with low to high salinity production water). Other advantages of the composition according to the present invention include: operational efficiencies which lead to the elimination of having to periodically circulate tanks of hydrochloric acid due to chemical separation; reduced corrosion to downhole tubulars; ultra-high temperature corrosion protection up to 220°C, less facility disruptions due to iron pick up and precipitation, thermal stability of a synthetic acid, and reduced hazardous hydrochloric acid exposure to personnel and environment by having a non-low hazard, low fuming acid (lower vapour pressure) on location. A synthetic acid composition according to a preferred embodiment of the present invention, can be used to treat scale formation in SAGD operations at ultra-high temperatures (up to 220°C) while achieving acceptable corrosion limits set by industry. This also eliminates the need for the SAGD operation to be halted for a ‘cool down’ prior to a scale treatment and said synthetic acid is injected into said well to treat scale formation inside said well at high temperatures.

While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by those skilled in the relevant arts, once they have been made familiar with this disclosure that various changes in form and detail can be made without departing from the true scope of the invention in the appended claims.