CROSS-REFERENCE TO RELATED APPLICATION

The present document is based on and claims priority to US Provisional Application Serial No. : 62/347142 , filed June 8, 2016, which is incorporated herein by reference in its entirety.

BACKGROUND

[0001] In the hydrocarbon drilling and production industry, crude oil refers to the desirable (and undesirable) hydrocarbon products extracted from the ground together with the associated aqueous phase and minor amounts of solids. The proportion of hydrocarbons in crudes varies from 5% to almost 100%, and includes thousands of different molecules that may be grouped into four families of compounds: saturates, aromatics, resins and asphaltenes.

[0002] Crude oils are transported over long distances through pipelines, and therefore, the pumpability of the crude oils through the pipelines may affect their transportation, as well as their processing. Most crude oils are characterized by their natural pour points thereby requiring the addition of pour points depressants as well as fluidity improvers as an aid to pipeline pumpability.

[0003] In the production of heavy and extra heavy oils, operator companies normally add diluents to the oil to reduce its viscosity and to facilitate the lifting from reservoir to surface, processing and transportation. High temperatures are also applied to dehydrate the oil, even when diluents are used. However, such strategies may destabilize the oil, generating higher viscosities at the end of the process. Normally, the increase is not detected but overcome by the addition of more diluents or applying higher temperatures, which results in higher costs for the operator.

SUMMARY

[0004] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subj ect matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. [0005] In one aspect, embodiments disclosed herein relate to a composition that includes a solvent and at least a sulphosuccinate.

[0006] In another aspect, embodiments of the present disclosure relate to a method of processing crude oil that includes injecting a flow improver composition comprising at least a sulphosuccinate into a diluent supply line, contacting a crude oil product with the flow improver composition mixed with the diluent to form a diluted crude oil and processing the diluted crude oil to form a processed crude oil.

[0007] In yet another aspect, embodiments disclosed herein relate to a method of processing crude oil that includes injecting a flow improver composition comprising at least a sulphosuccinate into a crude oil product with the formation of a treated crude oil and processing the treated crude oil to form a processed crude oil.

[0008] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

[0009] Embodiments of the present disclosure are described with reference to the following figures. The same numbers are used throughout the figures to reference like features and components.

[0010] FIG. 1 shows a flowchart for forming processed crude oil according to embodiments of the present disclosure.

DETAILED DESCRIPTION

[0011] Generally, embodiments disclosed herein relate to compositions and methods of using the same for reducing the viscosity of heavy and extra heavy crude oils. More specifically, embodiments disclosed herein relate to compositions formed of a solvent and at least a sulphosuccinate. The inventors of the present disclosure have found that compositions including a sulphosuccinate, such as dialkyl sulphosuccinates, blended in a solvent or a mixture of solvents may be used to improve the production and transportation of heavy and extra heavy crude oils when in contact with them by maintaining the fluid stability with their viscosities constant during its processing. This control of viscosity may allow the producer to operate with a lower viscosity fluid, which may increase production or may reduce the amount of diluent used, hence, reducing operational cost, among other benefits.

[0012] According to the present embodiments, the compositions of the present disclosure may contain a blend of chemicals that may aid in reducing the viscosity of heavy and extra heavy crude oils. Such chemical compositions that may act as flow improvers, may be prepared using sulphosuccinates. The sulphosuccinates that have shown utility in the present embodiments may be selected from the group of dialkylsulphosuccinates, such as for example, dioctylsulphosuccinates. For example, in one embodiment, EPT-3379, a sodium dioctylsulphosuccinate commercially available from MI-SWACO (Houston, TX) may be used. The sulphosuccinate component may be present in the flow improver formulation in an amount based on the total solvent mixture of from about 4% to about 26%.

[0013] In various embodiments, the sulphosuccinates may be blended with non-ionic surfactants such as ethoxylated esters. The ethoxylated esters that have shown utility in the present disclosure are selected from the group of ethoxylated sorbitan esters or polysorbates. In various embodiments, mixtures of at least two ethoxylated sorbitan esters may be employed. Suitable ethoxylated sorbitan esters that may be used include for example polyoxyethylene (20) sorbitan monolaureate (polysorbate 20 or sorbitan monolaureate with 20 EO), formed by ethoxylation of sorbitan before adding lauric acid, and polyoxyethylene (5) sorbitan monooleate (polysorbate 81 or sorbitan monooleate with 5 EO). The ethoxylation process leaves the molecule with 20 or 5, respectively, repeating units of polyethylene glycol. Further, it is envisioned that other amounts of ethoxylation as well as esters other than monolaureate and monooleate may be used. The ester component may be present in the formulation in an amount based on the total solvent mixture of from about 10% to about 25%, where the lower limit can be any of 10%, 12%, and 15% and the upper limit can be any of 20%, 22% and 25%, where any lower limit can be used with any upper limit.

[0014] In one or more embodiments, the composition may further include a cumene sulphonate, such as sodium cumene sulphonate. According to various embodiments, the molar ratio between the ethoxylated ester, cumene sulphonate and sulphosuccinate may range from about 2.5:2.5: 1 to about 1 :2.5:2.5. [0015] According to the present embodiments, the mixtures of ethoxylated ester, cumene sulphonate and sulphosuccinate may be blended in the presence of a solvent or a mixture of solvents, with the formation of a chemical composition that may act as a flow improver or viscosity reducer, maintaining heavy and extra heavy oils' viscosity constant in production operations. Upon contact of a composition as described herein with heavy or extra heavy crude oils, the fluid stability is maintained, while the viscosity of the fluid is constant during its processing. Without being bound by theory, the inventors of the present disclosure believe that the mechanism of controlling the viscosity of the crude oils relies on maintaining the asphaltenes in solution and avoiding their growth or aggregation. This is supported by tests performed during the development process using traditional asphaltenes dispersants and inhibitors. However, such additives did not generate any control on viscosity.

[0016] As noted above, the composition of the present disclosure may be prepared by blending its components in the presence of a solvent or a mixture of solvents. The solvent is selected in such a manner that does not have an impact on the performance of the composition. In addition, the solvent and mixture of solvents are selected in such a manner that is not objectionable in the jet fuel fraction of a downstream refinery.

[0017] In one or more embodiments, solvents may be selected from the group of aromatic solvents, aliphatic solvents, alcoholic solvents and mixtures thereof. In embodiments where a mixture of solvents is used, the aromatic hydrocarbon component may be present therein in an amount ranging from about 30% to about 45%. Suitable aromatic hydrocarbons include, but are not limited to xylene, toluene, refinery aromatic cuts boiling in a range from about 320-350°F (about 160-177°C), and the like and mixtures thereof. It is also envisioned that the solvent or the mixture of solvents may contain components other than aromatic hydrocarbons, such as alcohols, e.g. isopropyl alcohol (IP A) as one non-limiting example.

[0018] It is also envisioned that other additives may be added into the solvent, such as surfactants. Suitable anionic surfactants that may be used include the fatty alcohol sulfates such as the sulfates of alcohols having from 8 to 18 carbon atoms such as sodium lauryl sulfate, ethoxylated fatty alcohol sulfates, sulfonated alkyl aryl compounds such as dodecylbenzenesulfonic acid (DDBSA) or its sodium salt, sodium dodecylbenzene sulfonate, and fatty acids having 8 to 18 carbon atoms. In one or more embodiments, surfactants may be used in an amount ranging from 2% to 4% weight percent of the composition (wt%). In one or more embodiments, the solvent may include glycols in lesser extent. In embodiments where IPA is used as a solvent, the formulations are prepared by adding the sulphosuccinate into the solvent, followed by the addition of the ethoxylated ester, then cumene sulphonate and afterwards IPA. Next, a surfactant additive such as DDBSA may be added into the mixture.

[0019] Upon mixing, the compositions of the present embodiments may be used in production and transportation of heavy and extra heavy crude oils. The composition may be applied to the heavy and extra heavy crude oils at a dose rate of from about 150 ppm to about 600 ppm, where the lower limit can be any of 150 ppm, 170 ppm, and 200 ppm, and the upper limit can be any of 500 pp, 550 ppm, and 600 ppm, where any lower limit can be used with any upper limit. As noted above, the composition as described herein may reduce the viscosity of the diluted heavy oil by 20%-40%. The compositions and methods may also reduce the diluent use by 20%-50% .

[0020] There is no special method of introducing the composition as described herein into the crude oil. In various embodiments, the composition may be injected into the diluent supply line upstream to a producing well. For example, the composition of the present disclosure may be injected as upstream of the process as possible, being the recommended injection point at downhole of producing wells. According to the present embodiments, the composition may be added to a diluent which serves as a carrier fluid to distribute the chemical composition along the field and the producing wells, reducing injection points to the minimum. The composition may start acting as soon as it contacts the crude oil. The results in the field may be detected initially by a reduction of pressures at well head, downhole, booster and exporting pumps, and immediately after in an increase in flow rates. The reduction of final viscosity of the crude oil may be used to optimize the amount of diluent in the blend to reduce costs of operations, especially when most of the diluents cost more than the crude oil itself.

[0021] The compositions of the present disclosure may improve the flow of heavy and extra heavy oils in production facilities, which may include lifting operations from reservoir, processing or separation plants, and transportation until refineries by means of adding a chemical product into the stream to control its viscosity and avoid destabilization of the crude through the process. As defined herein, the heavy and extra heavy oils may have an API density ranging from about 8 "API to about 20 "API. Such heavy crude oil and extra heavy crude oils may be oil that has been dewatered at the well head or it may be heavy crude oil and extra heavy crude oil which has not been dewatered, or it may be heavy hydrocarbon such as those previously disclosed above or it may be mixtures of these.

[0022] According to various embodiments, diluents may be used to dilute heavy oil and reduce its viscosity for easier transportation. Generally, a distillation tower cut such as naphtha is used for heavy oil dilution and transportation. The added diluent may be recovered at the destination using distillation and the diluent may be subsequently pumped back for blending. In one or more embodiments, the diluent may include light crude oil, light synthetic crude oil and other light petroleum hydrocarbon fractions. The diluent may be present in an amount ranging from about 20% to about 30 % by weight of the fluid formulation, where the lower limit can be any of 20%, 20.5% and 21 %, and the upper limit can be any of 28%, 29% or 30%, where any lower limit can be used with any upper limit.

[0023] One embodiment of the present disclosure includes a method of processing crude oil. In one illustrative embodiment, the method involves injecting a flow improver composition comprising at least a sulphosuccinate (and optionally an ethoxylated ester and cumene sulphonate) into a diluent supply line, contacting a crude oil product with the flow improver composition mixed with the diluent to form a diluted crude oil and processing the diluted crude oil to form processed crude oil. According to various embodiments, the amount of the flow improver composition inj ected into the diluent line may range from about 150 ppm to about 300 ppm, where the lower limit can be any of 150 ppm, 170 ppm, and 200 ppm, and the upper limit can be any of 200 ppm, 250 ppm, or 300 ppm, where any lower limit can be used with any upper limit.

[0024] It is also envisioned that the flow improver composition may be injected directly into the crude oil. In one illustrative embodiment, the method of processing crude oil may involve injecting a flow improver composition comprising at least a sulphosuccinate (and optionally with an ethoxylated ester and cumene sulphonate) directly into a crude oil product when, upon contacting the crude oil product with the flow improver composition a treated crude oil is formed, and processing the treated crude oil to form a processed crude oil. In such embodiment, the amount of the flow improver composition injected into the oil may range from about 300 ppm to about 700 ppm.

[0025] Referring now to FIG. 1, FIG. 1 illustrates a method of processing crude oil that involves two well pads (100 and 110) containing heavy crude oil or extra heavy crude oil, which, after treatment with the flow improver compositions of the present disclosure, may be processed in a processing plant 120. The well pads 100 and 110 are fluidly connected to a diluent source 130 through a diluent line 150. The diluent source 130 is fluidly connected to two injection points 140, one that injects the flow improver composition 180 into the diluent line 150 that is fluidly connected to the well pad 100, and one that injects the flow improver composition 180 into the diluent line 150 that is fluidly connected to the well pad 110. As seen in FIG. 1, the flow improver composition 180 is injected into the diluent line 150 at the injection point 140. The flow improver composition carried by the diluent through the diluent line 150 enters the well pad 100, for example, where contacts the crude oil, with the formation of a diluted crude oil. This contact may be downhole, such as through an injection well or a production well. If injected through an injection well, the number of injection points may be reduced as the flow improver is carried through the field via the injection well. The injection may also occur directly through the production well, such as through a bypass line. Whether injected through an injection well or a production well, the interaction of the flow improver on the crude oil may be detected by a reduction of pressure at the wellhead, downhole, or pumps, followed by an increase in flow rate of the produced crude. The diluted crude oil (not shown) is transported through the diluted crude oil line 160 to the processing plant 120. As seen in FIG. 1, the diluted crude oil exiting the well pad 100 may be combined with diluted crude oil that exits the well pad 110 through the diluted crude oil line 160. The combined diluted crude oil may be processed in the processing plant 120 with the formation of a processed crude oil (not shown) that exits the processing plant 120 through a processed crude oil line (exporting line) 170. In a particular embodiment, the injection of the flow improver composition into the diluent supply line is performed upstream to a producing well. It is also envisioned that the flow improver compositions as described herein may be injected as crude flows through a pipeline, such as downstream of the wellhead.

[0026] EXAMPLES [0027] The following examples are presented to further illustrate the properties of various flow improver compositions in accordance with the present disclosure, and should not be construed to limit the scope of the disclosure, unless otherwise expressly indicated in the appended claims. Specifically, the viscosities, η, of crude oils were studied using a Brookfield viscometer using ASTM D2196-10 as the main reference. The samples of oil used in the experiments were removed of free water and pre-heated before each test. The amount of Basic Sediments and Water (% BSW) was minimum in the tests with a maximum of 2%. A mathematical regression of the results was used to predict viscosity results on higher temperatures. For comparison purposes, the experiments were performed with oil with no chemical composition, oil with diluent and no chemical composition, and oil with diluent with chemical composition. For each of them, the oil and diluent samples were pre-heated at 65°C for one hour and shaken before each viscosity measurement. At temperatures above 65°C some diluents evaporated. The procedures used for each stage of the experiment are described below.

[0028] Oil with no diluent or chemical composition: 1) With the temperature of the water bath set to 65°C, place the sample container in the water bath for 1 hour. 2) Shake periodically to mix the sample well. 3) Remove the sample container from the water bath. 4) After 1 hour, pour the sample oil into a beaker and place under the Brookfield Viscometer. 5) With the proper Brookfield spindle, put the spindle in the oil and measure the viscosity of the oil using ASTM D2196-10. 6) Record viscosity and temperature. 7) Set the temperature of the water bath to 60°C. 8) Pour the oil from the beaker into the sample container and place in the water bath at 60°C for 30 minutes. 9) Shake periodically to mix the sample. 10) After 30 minutes and with the same Brookfield spindle in the oil, measure the viscosity of the oil using ASTM D2196-10. 11) Record viscosity and temperature. 12) Repeat 4-11 for 55°C, 50°C and 45°C, record viscosity and temperature for each measurement.

[0029] Oil with diluent without chemical composition: 1) For 14 °API oil, 20% weight naphtha was used and for 9 "API oil, 25% weight naphtha was used. 2) For 250 ml of sample: a) 9 °API: 62.5 g of naphtha plus 187.5 g of oil; b) 14 °API: 50 g of naphtha plus 200 g of oil. 3) Mix the oil with the naphtha in the tin can and shake well. 4) With the temperature of the water bath set to 65 °C, place the sample container in the water bath for 1 hour. 5) Shake periodically to mix the sample well. 6) Remove the sample container from the water bath. 7) Pour the sample oil into a beaker and place under the Brookfield Viscometer. 8) With the proper Brookfield spindle, put the spindle in the oil and measure the viscosity of the oil using ASTM D2196-10. 9) Set the rpm for the spindle to give the required torque (between 10% and 95%). 10) Measure viscosity and record result and oil temperature. 11) Set the temperature of the water bath to 60°C. 12) Pour the oil from the beaker into the sample container and place in the water bath at 60°C for 30 minutes. 13) Shake periodically to mix the sample. 14) After 30 minutes and with the same Brookfield spindle in the oil at the same rpm, measure the viscosity of the oil using ASTM D2196-10. 15) Measure viscosity and record result and oil temperature. 16) Pour the oil from the beaker into the metal can and place in the water bath. 17) Repeat 11-15 for 55°C, 50°C and 45°C. Oil with diluent and chemical composition: 1) For 14 °API oil 20% weight naphtha was used and for 9 "API oil 25% weight naphtha was used. 2) For 250 ml of sample: a) 9 °API: 62.5 g of naphtha plus 187.5 g of oil; b) 14 °API: 50 g of naphtha plus 200 g of oil. 3) Weigh the proper amount of naphtha into the sample can. 4) Add 125 microlitres of chemical to the naphtha (500 ppm) and shake to mix. 5) Weigh the required amount of crude oil into the can. 6) Mix the oil with the naphtha in the tin can and shake well. 7) With the temperature of the water bath set to 65°C, place the sample container in the water bath for 1 hour. 8) Shake periodically to mix the sample well. 9) Remove the sample container from the water bath. 10) Pour the sample oil into a beaker and place under the Brookfield Viscometer. 11) With the proper Brookfield spindle, put the spindle in the oil and measure the viscosity of the oil using ASTM D2196-10. 12) Set the rpm for the spindle to give the required torque. 13) Measure and record the oil temperature. 14) Input the result in the "Input" sheet. 15) Set the temperature of the water bath to 60°C. 16) Pour the oil from the beaker into the sample container and place in the water bath at 60°C for 30 minutes. 17) Shake periodically to mix the sample. 18) After 30 minutes and with the same Brookfield spindle in the oil at the same rpm, measure the viscosity of the oil using ASTM D2196-10. 19) Measure and record the oil temperature. 20) Input the result in the "Input" sheet. 21) Pour the oil from the beaker into the metal can and place in the water bath. 22) Repeat 17-22 for 55°C, 50°C and 45°C. [0031] A list of formulations that were used during the development and their compositions are shown in Table 1. Material 3 is EPT-3379, a sodium dioctyl sulfosuccinate commercially available from M-I SWACO.

[0032] The main results are presented in Tables 2 and 3. The experiments were completed in heavy and extra heavy oils obtained from different fields in Venezuela, Colombia and Ecuador.

Table 1. Examples of different formulations used in the development process.

Table 2 shows results of chemicals in extra heavy oil from Colombia. The experiments in this crude oil included blends of ethoxylated sorbitans, cumene sulphonate and a dioctylsulphosuccinate achieving reduction of viscosity up to 42% (formulations 2 and 5) when compared to the untreated oil.

Table 2. Results obtained with formulations 1 and 2 in heavy oil of 9 °API from Colombia diluted with naphtha Temp. °C r| (cP) Temp. °C r| (cP) Temp. °C r| (cP)

65.4 30.2 65.2 27.1 65.3 24.2

59.5 46.6 59.5 37 59 32.1

53.2 76.4 53.1 58.2 53 44.4

50.3 100 50.2 73.9 50 57.7

Table 3 contains the results obtained with the mixture of ethoxylated sorbitans and dioctylsulphosuccinate in an extra heavy oil from Venezuela (8°API) mixed with light oil which showed superior performances compared to the blank.

Table 3. Results obtained with formulations 1, 3 and 4 in crude oil of 8 °API from Venezuela diluted with light oil.

[0035] Advantageously, embodiments of the present disclosure may provide compositions and methods of using the same that improve the production and transportation of heavy and extra heavy crude oils. The control of viscosity using the compositions as described herein may allow operating with a lower viscosity fluid which may increase production and reduce the amount of diluent used, reducing operational costs.

[0036] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words 'means for' together with an associated function.