[0001] Seawater Injection Facilities for Improved Oil Recovery / Enhanced Oil Recovery on a Barge for Offshore Platforms

CROSS REFERENCE TO RELATED APPLICATIONS [0002] Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0003] Not applicable.

REFERENCE TO APPENDIX

[0004] Not applicable.

BACKGROUND OF THE INVENTION

[0005] Field of the Invention.

[0006] The disclosure generally relates to large scale supplies of seawater for offshore platforms. More specifically, the disclosure relates to a specialized barge for providing large scale supplies of seawater for offshore platforms.

[0007] Description of the Related Art.

[0008] In the oil industry, water is injected into an underground hydrocarbon formation through a stimulation well to stimulate production and increase oil recovery through an associated hydrocarbon well in a reservoir of the formation. Water is injected to support pressure of the reservoir, and also to sweep or displace oil from the reservoir, and push it toward the hydrocarbon well. For offshore wells, seawater is a natural resource. However, the volume and flow rate that are needed for well stimulation are seldom available from the offshore platform. Independent self-powered vessels, such as converted tankers and other supply vessels, are typically used for intake, pumping, treatment, and supply to the offshore platform and are sometimes referred to as a "well stimulation vessel" ("WSV"). A WSV typically floats nearby to the offshore platform that is producing the well and may have a supply riser connected to the platform or even directly to a stimulation well near to the platform. Such self-powered vessels can be held in position typically by a dynamic positioning system with thrusters using GPS coordinates or by mooring lines. However, such special purpose vessels are expensive and historically have limited availability.

[0009] Therefore, there is an unmet need for an inexpensive and readily available system and method to supply high volumes of seawater to an offshore platform for injection into a hydrocarbon formation.

BRIEF SUMMARY OF THE INVENTION

[0010] The disclosure provides a system and method of use for a barge for seawater injection. A classical barge can be outfitted with multiple modules to establish a readily available connection to "plug and produce" to hydrocarbon production equipment. Modules can be installed on the classical barge for seawater processing and injection, support facilities, utilities, and pipe, such as flexible pipe around a pipe reel. The barge can be moved to a site, the pipe can be connected from the barge to the production equipment, and the barge moved to a distance from the production equipment with the pipe being deployed. The barge can be anchored to the seabed and does not need to be powered or have thrusters for positioning. Ballast can be attached along the flexible pipe to lower a position of the flexible pipe toward the seabed to allow supply and other vessels to safely pass therebetween.

[001 1] The disclosure provides a seawater injection system for supplying seawater to an offshore hydrocarbon production site, comprising: a barge that requires assistance of a powered vessel to move the barge to the offshore hydrocarbon production site; seawater injection equipment coupled to the barge; and a pipe coupled to the seawater injection equipment and configured to be coupled to hydrocarbon production equipment at the offshore hydrocarbon production site to supply seawater from the barge to the production equipment.

[0012] The disclosure also provides a method of supplying seawater to hydrocarbon production equipment at an offshore hydrocarbon production site, comprising: moving a barge to an offshore hydrocarbon production site, the barge having seawater injection equipment coupled to the barge and a pipe coupled to the seawater injection equipment; connecting the pipe to hydrocarbon production equipment at the offshore hydrocarbon production site; and supplying seawater from the barge to the production equipment through the pipe.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0013] Figure 1 is a schematic side view of a seawater injection system of the present invention having a barge.

[0014] Figure 2 is a schematic diagram of exemplary seawater processing equipment for the seawater injection system of Figure 1.

[0015] Figure 3 is a schematic side view of the exemplary barge shown in Figure 1 moved to a location adjacent hydrocarbon production equipment at an offshore hydrocarbon production site to couple a pipe to the production equipment.

[0016] Figure 4 is a schematic side view of the barge moving away from the production equipment and deploying a ballasted pipe coupled to the production equipment.

[0017] Figure 5 is a schematic side view of the barge located a distance away from the production equipment with ballasted pipe being deployed near the seabed between the barge and the production equipment.

[0018] Figure 6 is a schematic side view of the barge located a distance away from another embodiment of the production equipment, such as an offshore production platform, with ballasted pipe being deployed near the seabed between the barge and the production equipment.

[0019] Figure 7 is a schematic side view of the barge located a distance away from another embodiment of the production equipment, such as an offshore wellhead platform, with ballasted pipe being deployed near the seabed between the barge and the production equipment.

[0020] Figure 8 is a schematic side view of the barge located a distance away from another embodiment of the production equipment, such as an offshore subsea wellhead, with ballasted pipe being deployed near the seabed between the barge and the production equipment.

DETAILED DESCRIPTION

[0021] The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what the Applicant has invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present disclosure will require numerous implementation- specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation location and vary from time to time. While a developer's efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. The use of a singular term, such as, but not limited to, "a," is not intended as limiting of the number of items. Further, the various methods and embodiments of the system can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa. References to at least one item may include one or more items. Also, various aspects of the embodiments could be used in conjunction with each other to accomplish the understood goals of the disclosure. Unless the context requires otherwise, the term "comprise" or variations such as "comprises" or "comprising," should be understood to imply the inclusion of at least the stated element or step or group of elements or steps or equivalents thereof, and not the exclusion of a greater numerical quantity or any other element or step or group of elements or steps or equivalents thereof. The device or system may be used in a number of directions and orientations. The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

[0022] The disclosure provides a system and method of use for a barge for seawater injection. A classical barge can be outfitted with multiple modules to establish a readily available connection to "plug and produce" to hydrocarbon production equipment. Modules can be installed on the classical barge for seawater processing and injection, support facilities, utilities, and pipe, such as flexible pipe around a pipe reel. The barge can be moved to a site, the pipe can be connected from the barge to the production equipment, and the barge moved to a distance from the production equipment with the pipe being deployed. The barge can be anchored to the seabed and does not need to be powered or have thrusters for positioning. Ballast can be attached along the flexible pipe to lower a position of the flexible pipe toward the seabed to allow supply and other vessels to safely pass therebetween.

[0023] Figure 1 is a schematic side view of the seawater injection system having a barge. An offshore hydrocarbon production site 2 can include various hydrocarbon production equipment 4 for extracting hydrocarbons from a subsea hydrocarbon well 20, including for injecting fluids into an associated stimulation well 22. The term "hydrocarbon production equipment" refers to equipment used to produce hydrocarbons from a hydrocarbon well at the offshore hydrocarbon production site, and includes equipment such as a wellhead on an associated stimulation well into which injection fluids are pumped to produce hydrocarbons from the hydrocarbon well. The hydrocarbon production equipment will generally include a pipe connector along a flow path that can be coupled to the pipe from the seawater injection system. In at least one embodiment, the production equipment 4 can include an offshore platform. The platform can include a floating platform or jack up leg platform, or any other variety of platforms that is used hydrocarbon exploration and extraction from the seabed 48. The production equipment 4 can also include a production platform, wellhead platform, or subsea wellhead. [0024] To provide seawater to the production equipment 4 for water injection, a seawater injection system 6 can be towed, pulled, pushed, or otherwise moved to the site 2. The seawater injection system 6 can include a barge 8 equipped with seawater injection equipment 10. The barge can be a classical barge, that is, generally a non-powered floating structure commonly used in transportation of variety of goods and towed, pulled, pushed, or otherwise moved by a separate powered vessel. The barge 8 can be further equipped with accommodation facilities 12 including living quarters, control room, and other support facilities. The barge 8 can be further equipped with a mooring system 14 for stabilizing the position of the barge for the seawater injection operation. The seawater injection equipment 10 and other structures on the barge can be modular to enable rapid outfitting of a classical barge and hence rapid supply and deployment of the seawater injection system 6.

[0025] The barge includes a quantity of pipe 16, such as flexible pipe for subsea deployment, that can be coupled to the seawater injection equipment 10 and, upon deployment of the pipe, to the production equipment 4. While the pipe 16 is shown forming a simple loop configuration for schematic purposes in the Figures, in practice the configuration of the pipe can vary, including a lazy wave riser configuration that can form an "S" shape for more flexibility in movement between the seawater injection equipment 10 and the production equipment 4. In at least one embodiment, the pipe 16 can be coupled with ballast 18. The ballast 18 can include a variety of weights or adjustable buoyancy members that can change the elevation of the pipe to a position at which the pipe would not naturally be disposed. For example, ballast such as clamp weights can be coupled to the pipe 16 and be used to lower the pipe 16 to the seabed 48 between the barge 8 and the production equipment. In other embodiments, the ballast 18 can be used to position the pipe 16 at an intermediate elevation between the water surface and the seabed, or in other embodiments at a floating position at the surface. In some embodiments, the ballast 18 can be adjustable at different buoyancy levels.

[0026] Figure 2 is a schematic diagram of exemplary seawater processing equipment for the seawater injection system of Figure 1. The seawater injection system 6 includes the barge 8 and the seawater injection equipment 10. The seawater injection equipment 10 can include a variety of subsystems for pumping, filtration, chemical treatment, and other processes for providing seawater to the production equipment 4. Thus, the embodiment in Figure 2 is merely exemplary and other configurations can be made. A lifting pump 24 can be deployed from the barge 8 to a subsurface level in the water to pump seawater into the remaining equipment. The sea water from the lifting pump 24 can be pumped through a bio-fouling control subsystem 26, treated by a polyelectrolyte and scale inhibitor chemical treatment subsystem 34A (the various chemical treatment subsystem components being generally referred to as a chemical treatment subsystem 34), filtered by a coarse filtration subsystem 28 and then a fine-media filtration subsystem 30, treated by an antifoam and biocide chemical treatment subsystem 34B, deaerated with a vacuum deaeration subsystem 32, treated by an oxygen scavenger chemical treatment subsystem 34C, pumped by a booster pump 36, and flowed to an injection pump 38 that is useful to develop the high pressure and high volume for the seawater injection to the production equipment and into the stimulation well. Scale and corrosion inhibitors can be applied to the seawater downstream of the injection pump 38 by a scale and corrosion inhibitor chemical treatment subsystem 34D. Other options for treatment include flowing the seawater through a low salinity ("LOSAL") subsystem 56 for partial desalination that may occur prior to the deaeration subsystem 32, and treated with an alkali surfactant polymer ("ASP") injection subsystem 34E for an additional chemical treatment that may occur downstream of the injection pump 38. The injection pump 38 provides the seawater through the subsea flexible pipe 16. In at least one embodiment, the pipe 16 can be a flexible pipe that can allow coiling of the pipe around a pipe reel 40. The term "flexible pipe" is used broadly and can include continuous or joints of flexible pipe or can include joints of rigid pipe with gimbaled joints and swivel joints that allow the pipe to flexibly change angles as needed. In other embodiments, joints of rigid pipe could be used with various fittings to make the different angles as needed.

[0027] Figures 3-5 illustrate an exemplary and nonlimiting embodiment of a method for providing seawater for injection to the hydrocarbon production equipment at the offshore hydrocarbon production site 2. Figure 3 is a schematic side view of the exemplary barge shown in Figure 1 moved to a location adjacent hydrocarbon production equipment 4 at an offshore hydrocarbon production site 2 to couple a pipe 16 for supplying the seawater to the production equipment. The seawater injection system 6 that includes the barge 8 in the seawater injection equipment 10 can be towed, pushed, or otherwise transported to the production site 2. The pipe 16 can be partially deployed sufficient to be raised and connected to an end fitting 44 on the production equipment. The pipe 16 can be guided toward the end fitting 44 by a tapering bell mouth 42. For example, a crane on the production equipment 4 could lift the partially deployed pipe 16 to make the coupling to the end fitting.

[0028] Figure 4 is a schematic side view of the barge moving away from the production equipment and deploying a ballasted pipe coupled to the production equipment. The seawater injection system 6 can be moved away from the production equipment 4 such as by towing, pulling, or pushing the barge with a separate vessel and the pipe 16 further deployed to accommodate the increased distance. The pipe 16 can remain coupled to the production equipment 4 during the movement. Ballast 18 can be coupled to the pipe 16, such as while the pipe is being deployed. In at least one embodiment, the ballast will pull by gravity the pipe 16 toward the seabed 48.

[0029] Figure 5 is a schematic side view of the barge located a distance away from the production equipment with ballasted pipe being deployed near the seabed between the barge and the production equipment. Once the seawater injection system 6 is stationed at an appropriate distance from the production equipment, the system 6 can be moored to the seabed with one or more mooring lines 50. The pipe 16 is shown fully deployed with ballast 18 weighing down the pipe 16 to the seabed 48 to a depth Dl. Alternatively, the ballast 18 can be used to partially lowered the pipe 16 to a depth D2 that is higher in elevation than the depth Dl. The seawater injection equipment 10 can become operational and pump the seawater through the pipe 16 to the production equipment 4.

[0030] Figure 6 is a schematic side view of the barge located a distance away from another embodiment of the production equipment, such as an offshore production platform, with ballasted pipe being deployed near the seabed between the barge 8 and the production equipment 4. Similar processes can be performed as described in Figures 3-5 on other types of production equipment 4. For example, the production equipment 4 can include a production platform that may not include a derrick or other equipment that might be found on other types of platforms. [0031] Once seawater injection is complete, the subsea flexible pipe 16 can be disconnected from the end fitting 44 of the production equipment 4 and be retrieved onto the pipe reel 40. Any ballast can be removed as the pipe is retrieved and stored for reuse. The mooring system 14 can be retrieved or disconnected. The seawater injection system 6, including the barge 8 with the seawater injection equipment 10, can be relocated to another site for connection to other production equipment and reused for seawater injection at the other site.

[0032] Figure 7 is a schematic side view of the barge located a distance away from another embodiment of the production equipment, such as an offshore wellhead platform, with ballasted pipe being deployed near the seabed between the barge and the production equipment. In some embodiments, the seawater injection system 6 can provide the seawater through the pipe 16 to a wellhead platform, as another exemplary type of production equipment 4.

[0033] Figure 8 is a schematic side view of the barge located a distance away from another embodiment of the production equipment, such as an offshore subsea wellhead, with ballasted pipe being deployed near the seabed between the barge and the production equipment. In some embodiments, the production equipment 4 may include other equipment than a platform. For example, the production equipment 4 may include a subsea wellhead. An ROV 52 could be used to connect the pipe 16 under submerged conditions to the subsea wellhead.

[0034] Other and further embodiments utilizing one or more aspects of the invention described above can be devised without departing from the spirit of Applicant's invention. For example, the systems and processes can be varied to produce various levels of seawater treatment from the seawater injection system, various types of connections and pipe and ballast, and other types of and other variations can occur in keeping within the scope of the claims.

[0035] The invention has been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicant, but rather, in conformity with the patent laws, Applicant intends to protect fully all such modifications and improvements that come within the scope or range of equivalents of the following claims.