AU2009271072B2

AU2009271072B2 - Systems and methods for producing oil and/or gas

Info

Publication number: AU2009271072B2
Application number: AU2009271072A
Authority: AU
Inventors: Paul Clinton; Kees Van Gelder; Carolus Matthias Anna Maria Mesters; Patrick Guy Monin; Gerard Mulder; Raul Valdez; Claudia Van Den Berg; Dean Chien Wang
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 2008-07-14
Filing date: 2009-07-14
Publication date: 2012-10-11
Anticipated expiration: 2029-07-14
Also published as: AU2009271072A1; RU2011105154A; MX2011000563A; EP2318651A1; RU2510454C2; WO2010009118A1; CA2730284A1; US20110180254A1; CN102119258A; BRPI0916419A2

Abstract

A system for producing oil and/or gas from an underground formation comprising a first well in the formation; a mechanism to inject a miscible enhanced oil recovery formulation into the first well; a second well in the formation; a mechanism to produce oil and/or gas from the second well; wherein the first well and the second well comprise an interior of the system; a plurality of containment wells exterior to the first well and the second well; and a mechanism to inject a containment agent into the containment wells.

Description

WO 2010/009118 PCT/US2009/050530 SYSTEMS AND METHODS FOR PRODUCING OIL AND/OR GAS Field of the Invention 5 The present disclosure relates to systems and methods for producing oil and/or gas. Background of the Invention Enhanced Oil Recovery (EOR) may be used to increase oil recovery in fields worldwide. There are three main types of EOR, thermal, chemical/polymer and gas 10 injection, which may be used to increase oil recovery from a reservoir, beyond what can be achieved by conventional means - possibly extending the life of a field and boosting the oil recovery factor. Thermal enhanced recovery works by adding heat to the reservoir. The most widely practised form is a steamdrive, which reduces oil viscosity so that it can flow to 15 the producing wells. Chemical flooding increases recovery by reducing the capillary forces that trap residual oil. Polymer flooding improves the sweep efficiency of injected water. Miscible injection works in a similar way to chemical flooding. By injecting a fluid that is miscible with the oil, trapped residual oil can be recovered. Referring to Figure 1, there is illustrated prior art system 100. System 100 20 includes underground formation 102, underground formation 104, underground formation 106, and underground formation 108. Production facility 110 is provided at the surface. Well 112 traverses formations 102 and 104, and terminates in formation 106. The portion of formation 106 is shown at 114. Oil and gas are produced from formation 106 through well 112, to production facility 110. Gas and liquid are 25 separated from each other, gas is stored in gas storage 116 and liquid is stored in liquid storage 118. U.S. Patent Number 7,225,866 discloses that an oil shale formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H 2 , and/or other formation fluids may be produced from the formation. Heat may be applied to the 30 formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat sources may be used to heat the formation. The heat sources 1 2 may be positioned within the formation in a selected pattern. U.S. Patent Number 7,225,866 is herein incorporated by reference in its entirety. Co-pending U.S. Patent Application Publication Number 2006/0254769, published November 16, 2006, and having attorney docket number TH2616, discloses a system including a s mechanism for recovering oil and/or gas from an underground formation, the oil and/or gas comprising one or more sulfur compounds; a mechanism for converting at least a portion of the sulfur compounds from the recovered oil and/or gas into a carbon disulfide formulation; and a mechanism for releasing at least a portion of the carbon disulfide formulation into a formation. U.S. Patent Application Publication Number 2006/0254769 is herein incorporated by reference io in its entirety. There is a need in the art for improved systems and methods for enhanced oil recovery. There is a further need in the art for improved systems and methods for enhanced oil recovery using a solvent, for example through viscosity reduction, chemical effects, and miscible flooding. There is a further need in the art for improved systems and methods for solvent miscible flooding. 15 SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a system for producing oil or gas from an underground formation comprising: an enhanced oil recovery formulation comprising carbon disulfide, wherein the enhanced oil recovery formulation is miscible with oil; 20 a first well in the formation; a mechanism to inject the enhanced oil recovery formulation into the first well; a second well in the formation; a mechanism to produce oil or gas from the second well; wherein the first well and the second well comprise an interior of the system; 25 a plurality of containment wells exterior to the first well and the second well; and a mechanism to inject a containment agent into the containment wells. According to a second aspect of the present invention, there is provided A method for producing oil or gas comprising: 2a injecting a carbon disulfide formulation into a formation from a first well; producing oil or gas from the formation from a second well; and injecting a containment agent into the formation from a plurality of containment wells. According to a third aspect of the present invention, there is provided a method for producing oil 5 or gas comprising: injecting an oil recovery formulation that is miscible with oil into an oil-bearing formation from a first well; producing oil or gas from the formation from a second well; and injecting a containment agent into the formation from plurality of containment wells. io According to a fourth aspect of the present invention, there is provided oil or gas produced by the method of any one of claims 15 to 24 or 26. In one aspect, the invention provides a system for producing oil and/or gas from an underground formation comprising a first well in the formation; a mechanism to inject a miscible enhanced oil recovery formulation into the first well; a second well in the formation; a mechanism to produce is oil and/or gas from the second well; wherein the first well and the second well comprise an interior of the system; a plurality of containment wells exterior to the first well and the second well; and a mechanism to inject a containment agent into the containment wells. In another aspect, the invention provides a method for producing oil and/or gas comprising injecting a carbon disulfide formulation into a formation from a first well; producing oil and/or 20 gas from the formation from a second well; and injecting a containment agent into the formation from a plurality of containment wells. In some embodiments, the method also includes recovering carbon disulfide formulation from the oil and/or gas, if present, and then injecting at least a portion of the recovered carbon disulfide formulation into the formation.

WO 2010/009118 PCT/US2009/050530 In another aspect, the invention provides a method for producing oil and/or gas comprising injecting a miscible enhanced oil recovery formulation into a formation from a first well; producing oil and/or gas from the formation from a second well; and injecting a containment agent into the formation from plurality of containment wells. 5 Advantages of the invention include one or more of the following: Improved systems and methods for enhanced recovery of hydrocarbons from a formation with a solvent. Improved systems and methods for enhanced recovery of hydrocarbons from a formation with a fluid containing a miscible solvent. 10 Improved compositions and/or techniques for secondary recovery of hydrocarbons. Improved systems and methods for enhanced oil recovery. Improved systems and methods for enhanced oil recovery using a miscible solvent. 15 Improved systems and methods for enhanced oil recovery using a compound which is miscible with oil in place. Brief Description of the Drawinqs Figure 1 illustrates an oil and/or gas production system. Figure 2a illustrates a well pattern. 20 Figures 2b and 2c illustrate the well pattern of Figure 2a during enhanced oil recovery processes. Figures 3a-3c illustrate oil and/or gas production systems. Figure 4 illustrates a well pattern. Detailed Description of the Invention 25 Fiqure 2a: Referring now to Figure 2a, in some embodiments, an array of wells 200 is illustrated. Array 200 includes well group 202 (denoted by horizontal lines) and well group 204 (denoted by diagonal lines). Array 200 defines a production area, enclosed by the rectangle. Array 200 30 defines an interior of the system. Exterior to array 200 are located a plurality of containment wells 250. 3 WO 2010/009118 PCT/US2009/050530 Each well in well group 202 has horizontal distance 230 from the adjacent well in well group 202. Each well in well group 202 has vertical distance 232 from the adjacent well in well group 202. Each well in well group 204 has horizontal distance 236 from the adjacent well 5 in well group 204. Each well in well group 204 has vertical distance 238 from the adjacent well in well group 204. As shown in Figure 2a, horizontal distance 230 and horizontal distance 236 refer to a distance from left to right of the paper, and vertical distance 232 and vertical distance 238 refer to a distance from up to down of the paper. In practice, array may 10 be composed of vertical wells that are perpendicular to the earth's surface, horizontal wells that are parallel to the earth's surface, or wells that are inclined at some other angle, for example 30 to 60 degrees with respect to the earth's surface. Each well in well group 202 is distance 234 from the adjacent wells in well group 204. Each well in well group 204 is distance 234 from the adjacent wells in well 15 group 202. In some embodiments, each well in well group 202 is surrounded by four wells in well group 204. In some embodiments, each well in well group 204 is surrounded by four wells in well group 202. In some embodiments, horizontal distance 230 is from about 5 to about 1000 20 meters, or from about 10 to about 500 meters, or from about 20 to about 250 meters, or from about 30 to about 200 meters, or from about 50 to about 150 meters, or from about 90 to about 120 meters, or about 100 meters. In some embodiments, vertical distance 232 is from about 5 to about 1000 meters, or from about 10 to about 500 meters, or from about 20 to about 250 meters, 25 or from about 30 to about 200 meters, or from about 50 to about 150 meters, or from about 90 to about 120 meters, or about 100 meters. In some embodiments, horizontal distance 236 is from about 5 to about 1000 meters, or from about 10 to about 500 meters, or from about 20 to about 250 meters, or from about 30 to about 200 meters, or from about 50 to about 150 meters, or from 30 about 90 to about 120 meters, or about 100 meters. 4 WO 2010/009118 PCT/US2009/050530 In some embodiments, vertical distance 238 is from about 5 to about 1000 meters, or from about 10 to about 500 meters, or from about 20 to about 250 meters, or from about 30 to about 200 meters, or from about 50 to about 150 meters, or from about 90 to about 120 meters, or about 100 meters. 5 In some embodiments, distance 234 is from about 5 to about 1000 meters, or from about 10 to about 500 meters, or from about 20 to about 250 meters, or from about 30 to about 200 meters, or from about 50 to about 150 meters, or from about 90 to about 120 meters, or about 100 meters. In some embodiments, array of wells 200 may have from about 10 to about 10 1000 wells, for example from about 5 to about 500 wells in well group 202, and from about 5 to about 500 wells in well group 204. There may be provided from about 2 to about 1000 containment wells 250, for example from about 5 to about 500, or from about 10 to about 200. In some embodiments, array of wells 200 is seen as a top view with well group 15 202 and well group 204 being vertical wells spaced on a piece of land. In some embodiments, array of wells 200 is seen as a cross-sectional side view with well group 202 and well group 204 being horizontal wells spaced within a formation. The recovery of oil and/or gas with array of wells 200 from an underground formation may be accomplished by any known method. Suitable methods include 20 subsea production, surface production, primary, secondary, or tertiary production. The selection of the method used to recover the oil and/or gas from the underground formation is not critical. The containment of oil and/or gas and/or an enhanced oil recovery agent with containment wells 250 may be accomplished by any known method. Suitable 25 methods include pumping water, a peroxide such as hydrogen peroxide or a solution of hydrogen peroxide in water, carbon dioxide, natural gas or other gaseous or liquid hydrocarbons, nitrogen, air, brine, or other liquids or gases into containment wells 250. In another embodiment, containment wells 250 may be used to create a freeze wall barrier. One suitable freeze wall barrier is disclosed in U.S. Patent Number 30 7,225,866 is herein incorporated by reference in its entirety. The selection of the 5 WO 2010/009118 PCT/US2009/050530 method used to contain oil and/or gas and/or an enhanced oil recovery agent with containment wells 250 is not critical. In some embodiments, oil and/or gas may be recovered from a formation into a well, and flow through the well and flowline to a facility. In some embodiments, 5 enhanced oil recovery, with the use of an agent for example steam, water, a surfactant, a polymer flood, and/or a miscible agent such as a carbon disulfide formulation or carbon dioxide, may be used to increase the flow of oil and/or gas from the formation. In some embodiments, oil and/or gas recovered from a formation may include 10 a sulfur compound. The sulfur compound may include hydrogen sulfide, mercaptans, sulfides and disulfides other than hydrogen disulfide, or heterocyclic sulfur compounds for example thiophenes, benzothiophenes, or substituted and condensed ring dibenzothiophenes, or mixtures thereof. In some embodiments, a sulfur compound from the formation may be 15 converted into a carbon disulfide formulation. The conversion of at least a portion of the sulfur compound into a carbon disulfide formulation may be accomplished by any known method. Suitable methods may include oxidation reaction of the sulfur compound to sulfur and/or sulfur dioxides, and by reaction of sulfur and/or sulfur dioxide with carbon and/or a carbon containing compound to form the carbon disulfide 20 formulation. The selection of the method used to convert at least a portion of the sulfur compound into a carbon disulfide formulation is not critical. In some embodiments, a suitable miscible enhanced oil recovery agent may be a carbon disulfide formulation. The carbon disulfide formulation may include carbon disulfide and/or carbon disulfide derivatives for example, thiocarbonates, xanthates 25 and mixtures thereof; and optionally one or more of the following: hydrogen sulfide, sulfur, carbon dioxide, hydrocarbons, and mixtures thereof. In some embodiments, a suitable method of producing a carbon disulfide formulation is disclosed in copending U.S. Patent Application having serial number 11/409,436, filed on April 19, 2006, having attorney docket number TH2616. U.S. 30 Patent Application having serial number 11/409,436 is herein incorporated by reference in its entirety. 6 WO 2010/009118 PCT/US2009/050530 Figure 2b: Referring now to Figure 2b, in some embodiments, array of wells 200 is illustrated. Array 200 includes well group 202 (denoted by horizontal lines) and well group 204 (denoted by diagonal lines). Containment wells 250 are provided about 5 array of wells 200. In some embodiments, a miscible enhanced oil recovery agent is injected into well group 204, and oil is recovered from well group 202. As illustrated, the miscible enhanced oil recovery agent has injection profile 208, and oil recovery profile 206 is being produced to well group 202. In some embodiments, a containment agent is 10 injected into containment wells 250. As illustrated, the containment agent has an injection profile about each of the containment wells 250. Containment agent may be used to force miscible enhanced oil recovery agent and/or oil and/or gas towards producing well group 202. In some embodiments, a miscible enhanced oil recovery agent is injected into 15 well group 202, and oil is recovered from well group 204. As illustrated, the miscible enhanced oil recovery agent has injection profile 206, and oil recovery profile 208 is being produced to well group 204. In some embodiments, a containment agent is injected into containment wells 250. As illustrated, the containment agent has an injection profile about each of the containment wells 250. Containment agent may be 20 used to force miscible enhanced oil recovery agent and/or oil and/or gas towards producing well group 204. In some embodiments, well group 202 may be used for injecting a miscible enhanced oil recovery agent, and well group 204 may be used for producing oil and/or gas from the formation for a first time period; then well group 204 may be used 25 for injecting a miscible enhanced oil recovery agent, and well group 202 may be used for producing oil and/or gas from the formation for a second time period, where the first and second time periods comprise a cycle. In some embodiments, multiple cycles may be conducted which include alternating well groups 202 and 204 between injecting a miscible enhanced oil 30 recovery agent, and producing oil and/or gas from the formation, where one well 7 WO 2010/009118 PCT/US2009/050530 group is injecting and the other is producing for a first time period, and then they are switched for a second time period. In some embodiments, a cycle may be from about 12 hours to about 1 year, or from about 3 days to about 6 months, or from about 5 days to about 3 months. In 5 some embodiments, each cycle may increase in time, for example each cycle may be from about 5% to about 10% longer than the previous cycle, for example about 8% longer. In some embodiments, a miscible enhanced oil recovery agent or a mixture including a miscible enhanced oil recovery agent may be injected at the beginning of 10 a cycle, and an immiscible enhanced oil recovery agent or a mixture including an immiscible enhanced oil recovery agent may be injected at the end of the cycle. In some embodiments, the beginning of a cycle may be the first 10% to about 80% of a cycle, or the first 20% to about 60% of a cycle, the first 25% to about 40% of a cycle, and the end may be the remainder of the cycle. 15 In some embodiments, suitable miscible enhanced oil recovery agents include carbon disulfide, hydrogen sulfide, carbon dioxide, octane, pentane, LPG, C2-C6 aliphatic hydrocarbons, nitrogen, diesel, mineral spirits, naptha solvent, asphalt solvent, kerosene, acetone, xylene, trichloroethane, or mixtures of two or more of the preceding, or other miscible enhanced oil recovery agents as are known in the art. In 20 some embodiments, suitable miscible enhanced oil recovery agents are first contact miscible or multiple contact miscible with oil in the formation. In some embodiments, suitable immiscible enhanced oil recovery agents include water in gas or liquid form, air, mixtures of two or more of the preceding, or other immiscible enhanced oil recovery agents as are known in the art. In some 25 embodiments, suitable immiscible enhanced oil recovery agents are not first contact miscible or multiple contact miscible with oil in the formation. In some embodiments, an immiscible enhanced oil recovery agent and/or a miscible enhanced oil recovery agent may be used as a containment agent and injected into containment wells 250. 8 WO 2010/009118 PCT/US2009/050530 In some embodiments, immiscible and/or miscible enhanced oil recovery agents injected into the formation may be recovered from the produced oil and/or gas and re-injected into the formation. In some embodiments, oil as present in the formation prior to the injection of 5 any enhanced oil recovery agents has a viscosity of at least about 100 centipoise, or at least about 500 centipoise, or at least about 1000 centipoise, or at least about 2000 centipoise, or at least about 5000 centipoise, or at least about 10,000 centipoise. In some embodiments, oil as present in the formation prior to the injection of any enhanced oil recovery agents has a viscosity of up to about 5,000,000 centipoise, or 10 up to about 2,000,000 centipoise, or up to about 1,000,000 centipoise, or up to about 500,000 centipoise. Figure 2c: Referring now to Figure 2c, in some embodiments, array of wells 200 is illustrated. Array 200 includes well group 202 (denoted by horizontal lines) and well 15 group 204 (denoted by diagonal lines). Containment wells 250 are located exterior to array 200 to form a perimeter about array 200. In some embodiments, a miscible enhanced oil recovery agent is injected into well group 204, and oil is recovered from well group 202. As illustrated, the miscible enhanced oil recovery agent has injection profile 208 with overlap 210 with oil 20 recovery profile 206, which is being produced to well group 202. In some embodiments, a containment agent is injected into containment wells 250. As illustrated, the containment agent has an injection profile about each of the containment wells 250. Containment agent may be used to force miscible enhanced oil recovery agent and/or oil and/or gas towards producing well group 202. After a 25 sufficient period of time containment agent injection profile may overlap with one or more of injection profile 208 and oil recovery profile 206 so that enhanced oil recovery agent is contained within array 200; and/or so that oil and/or gas is contained within array 200; and/or so that containment agent is produced to well group 202. In some embodiments, a miscible enhanced oil recovery agent is injected into 30 well group 202, and oil is recovered from well group 204. As illustrated, the miscible enhanced oil recovery agent has injection profile 206 with overlap 210 with oil 9 WO 2010/009118 PCT/US2009/050530 recovery profile 208, which is being produced to well group 204. In some embodiments, a containment agent is injected into containment wells 250. As illustrated, the containment agent has an injection profile about each of the containment wells 250. Containment agent may be used to force miscible enhanced 5 oil recovery agent and/or oil and/or gas towards producing well group 204. After a sufficient period of time containment agent injection profile may overlap with one or more of injection profile 208 and oil recovery profile 206 so that enhanced oil recovery agent is contained within array 200; and/or so that oil and/or gas is contained within array 200; and/or so that containment agent is produced to well group 204. 10 Releasing at least a portion of the miscible enhanced oil recovery agent and/or other liquids and/or gases may be accomplished by any known method. One suitable method is injecting the miscible enhanced oil recovery formulation into a single conduit in a single well, allowing carbon disulfide formulation to soak, and then pumping out at least a portion of the carbon disulfide formulation with gas and/or 15 liquids. Another suitable method is injecting the miscible enhanced oil recovery formulation into a first well, and pumping out at least a portion of the miscible enhanced oil recovery formulation with gas and/or liquids through a second well. The selection of the method used to inject at least a portion of the miscible enhanced oil recovery formulation and/or other liquids and/or gases is not critical. 20 In some embodiments, the miscible enhanced oil recovery formulation and/or other liquids and/or gases may be pumped into a formation at a pressure up to the fracture pressure of the formation. In some embodiments, the miscible enhanced oil recovery formulation may be mixed in with oil and/or gas in a formation to form a mixture which may be recovered 25 from a well. In some embodiments, a quantity of the miscible enhanced oil recovery formulation may be injected into a well, followed by another component to force carbon the formulation across the formation. For example air, water in liquid or vapor form, carbon dioxide, other gases, other liquids, and/or mixtures thereof may be used to force the miscible enhanced oil recovery formulation across the formation. 10 WO 2010/009118 PCT/US2009/050530 In some embodiments, the miscible enhanced oil recovery formulation may be heated prior to being injected into the formation to lower the viscosity of fluids in the formation, for example heavy oils, paraffins, asphaltenes, etc. In some embodiments, the miscible enhanced oil recovery formulation may be 5 heated and/or boiled while within the formation, with the use of a heated fluid or a heater, to lower the viscosity of fluids in the formation. In some embodiments, heated water and/or steam may be used to heat and/or vaporize the miscible enhanced oil recovery formulation in the formation. In some embodiments, the miscible enhanced oil recovery formulation may be 10 heated and/or boiled while within the formation, with the use of a heater. One suitable heater is disclosed in copending United States Patent Application having serial number 10/693,816, filed on October 24, 2003, and having attorney docket number TH2557. United States Patent Application having serial number 10/693,816 is herein incorporated by reference in its entirety. 15 Fiqures 3a & 3b: Referring now to Figures 3a and 3b, in some embodiments of the invention, system 300 is illustrated. System 300 includes underground formation 302, underground formation 304, underground formation 306, and underground formation 308. Facility 310 is provided at the surface. Well 312 traverses formations 302 and 20 304, and has openings in formation 306. Portions 314 of formation 306 may be optionally fractured and/or perforated. During primary production, oil and gas from formation 306 is produced into portions 314, into well 312, and travels up to facility 310. Facility 310 then separates gas, which is sent to gas processing 316, and liquid, which is sent to liquid storage 318. Facility 310 also includes miscible enhanced oil 25 recovery formulation storage 330. As shown in Figure 3a, miscible enhanced oil recovery formulation may be pumped down well 312 that is shown by the down arrow and pumped into formation 306. Miscible enhanced oil recovery formulation may be left to soak in formation for a period of time from about 1 hour to about 15 days, for example from about 5 to about 50 hours. 30 Containment well 350 with injection mechanism 352 and containment well 360 with injection mechanism 362 may be provided to contain miscible enhanced oil 11 WO 2010/009118 PCT/US2009/050530 recovery formulation between containment well 350 and containment well 360. Injection mechanisms 352 and 362 may be used to inject a containment agent, for example a refrigerant to create a freeze wall, cement, liquid sulfur, or a liquid or gas such as water, peroxide, a peroxide solution, carbon dioxide, natural gas, other C1 5 C15 hydrocarbons, nitrogen, or air. After the soaking period, as shown in Figure 3b, miscible enhanced oil recovery formulation and oil and/or gas is then produced back up well 312 to facility 310. Facility 310 is adapted to separate and/or recycle miscible enhanced oil recovery formulation, for example by boiling the formulation, condensing it or filtering 10 or reacting it, then re-injecting the formulation into well 312, for example by repeating the soaking cycle shown in Figures 3a and 3b from about 2 to about 5 times. In some embodiments, miscible enhanced oil recovery formulation may be pumped into formation 306 below the fracture pressure of the formation, for example from about 40% to about 90% of the fracture pressure. 15 In some embodiments, well 312 as shown in Figure 3a injecting into formation 306 may be representative of a well in well group 202, and well 312 as shown in Figure 3b producing from formation 306 may be representative of a well in well group 204. In some embodiments, well 312 as shown in Figure 3a injecting into formation 20 306 may be representative of a well in well group 204, and well 312 as shown in Figure 3b producing from formation 306 may be representative of a well in well group 202. Figure 3c: Referring now to Figure 3c, in some embodiments of the invention, system 400 25 is illustrated. System 400 includes underground formation 402, formation 404, formation 406, and formation 408. Production facility 410 is provided at the surface. Well 412 traverses formation 402 and 404 has openings at formation 406. Portions of formation 414 may be optionally fractured and/or perforated. As oil and gas is produced from formation 406 it enters portions 414, and travels up well 412 to 30 production facility 410. Gas and liquid may be separated, and gas may be sent to gas storage 416, and liquid may be sent to liquid storage 418. Production facility 410 is 12 WO 2010/009118 PCT/US2009/050530 able to produce and/or store miscible enhanced oil recovery formulation, which may be produced and stored in production / storage 430. Hydrogen sulfide and/or other sulfur containing compounds from well 412 may be sent to miscible enhanced oil recovery formulation production / storage 430. Miscible enhanced oil recovery 5 formulation is pumped down well 432, to portions 434 of formation 406. Miscible enhanced oil recovery formulation traverses formation 406 to aid in the production of oil and gas, and then the miscible enhanced oil recovery formulation, oil and/or gas may all be produced to well 412, to production facility 410. Miscible enhanced oil recovery formulation may then be recycled, for example by boiling the formulation, 10 condensing it or filtering or reacting it, then re-injecting the formulation into well 432. Containment well 450 with injection mechanism 452 and containment well 460 with injection mechanism 462 may be provided to contain miscible enhanced oil recovery formulation between containment well 450 and containment well 460. Injection mechanisms 452 and 462 may be used to inject a containment agent, for 15 example a refrigerant to create a freeze wall, or a liquid or gas such as water, peroxide, a peroxide solution, carbon dioxide, natural gas, other C1 - C15 hydrocarbons, nitrogen, or air, or mixtures thereof. In some embodiments, a quantity of miscible enhanced oil recovery formulation or miscible enhanced oil recovery formulation mixed with other components may be 20 injected into well 432, followed by another component to force miscible enhanced oil recovery formulation or miscible enhanced oil recovery formulation mixed with other components across formation 406, for example air; water in gas or liquid form; water mixed with one or more salts, polymers, and/or surfactants; carbon dioxide; other gases; other liquids; and/or mixtures thereof. 25 In some embodiments, well 412 which is producing oil and/or gas is representative of a well in well group 202, and well 432 which is being used to inject miscible enhanced oil recovery formulation is representative of a well in well group 204. In some embodiments, well 412 which is producing oil and/or gas is 30 representative of a well in well group 204, and well 432 which is being used to inject 13 WO 2010/009118 PCT/US2009/050530 miscible enhanced oil recovery formulation is representative of a well in well group 202. Figure 4: Referring now to Figure 4, in some embodiments of the invention, an array of 5 wells 500 is illustrated. Array 500 includes well group 502 (denoted by horizontal lines) and well group 504 (denoted by diagonal lines). Array 500 defines a production area, enclosed by the rectangle. Array 500 defines an interior of the system. Exterior to array 500 are located internal containment wells 550, and external containment wells 552. Other arrays of 10 containment wells may also be provided (not shown). In some embodiments, a containment agent may be injected into internal containment wells 550 and external containment wells 552. In another embodiment, a containment agent may be injected into external containment wells 552, and the containment agent, oil and/or gas, and/or an enhanced oil recovery agent may be 15 produced from internal containment wells 550. Each well in well group 502 has horizontal distance 530 from the adjacent well in well group 502. Each well in well group 502 has vertical distance 532 from the adjacent well in well group 502. Each well in well group 504 has horizontal distance 536 from the adjacent well 20 in well group 504. Each well in well group 504 has vertical distance 538 from the adjacent well in well group 504. Each well in well group 502 is distance 534 from the adjacent wells in well group 504. Each well in well group 504 is distance 534 from the adjacent wells in well group 502. 25 In some embodiments, each well in well group 502 is surrounded by four wells in well group 504. In some embodiments, each well in well group 504 is surrounded by four wells in well group 502. Alternatives: In some embodiments, oil and/or gas produced may be transported to a 30 refinery and/or a treatment facility. The oil and/or gas may be processed to produce commercial products such as transportation fuels such as gasoline and diesel, 14 WO 2010/009118 PCT/US2009/050530 heating fuel, lubricants, chemicals, and/or polymers. Processing may include distilling and/or fractionally distilling the oil and/or gas to produce one or more distillate fractions. In some embodiments, the oil and/or gas, and/or the one or more distillate fractions may be subjected to a process of one or more of the following: catalytic 5 cracking, hydrocracking, hydrotreating, coking, thermal cracking, distilling, reforming, polymerization, isomerization, alkylation, blending, and dewaxing. Illustrative Embodiments: In one embodiment of the invention, there is disclosed a system for producing oil and/or gas from an underground formation comprising a first well in the formation; 10 a mechanism to inject a miscible enhanced oil recovery formulation into the first well; a second well in the formation; a mechanism to produce oil and/or gas from the second well; wherein the first well and the second well comprise an interior of the system; a plurality of containment wells exterior to the first well and the second well; and a mechanism to inject a containment agent into the containment wells. In some 15 embodiments, the first well is at a distance of 10 meters to 1 kilometer from the second well. In some embodiments, the underground formation is beneath a body of water. In some embodiments, the system also includes a mechanism for injecting an immiscible enhanced oil recovery formulation into the formation, after the miscible enhanced oil recovery formulation has been released into the formation. In some 20 embodiments, the system also includes a miscible enhanced oil recovery formulation selected from the group consisting of a carbon disulfide formulation, hydrogen sulfide, carbon dioxide, octane, pentane, LPG, C2-C6 aliphatic hydrocarbons, nitrogen, diesel, mineral spirits, naptha solvent, asphalt solvent, kerosene, acetone, xylene, trichloroethane, and mixtures thereof. In some embodiments, the system also 25 includes an immiscible enhanced oil recovery formulation selected from the group consisting of water in gas or liquid form, air, and mixtures thereof. In some embodiments, the system also includes a first array of wells comprising from 5 to 500 wells, and a second array of wells comprising from 5 to 500 wells. In some embodiments, the system also includes a miscible enhanced oil recovery formulation 30 comprising a carbon disulfide formulation. In some embodiments, the system also includes a mechanism for producing a carbon disulfide formulation. In some 15 WO 2010/009118 PCT/US2009/050530 embodiments, the underground formation comprises an oil having a viscosity from 100 to 5,000,000 centipoise. In some embodiments, the first well comprises a miscible enhanced oil recovery formulation profile in the formation, and the second well comprises an oil recovery profile in the formation, the system further comprising 5 an overlap between the miscible enhanced oil recovery formulation profile and the oil recovery profile. In some embodiments, the containment agent is selected from the group consisting of a refrigerant, water, brine, peroxide, peroxide solutions, nitrogen, air, carbon dioxide, natural gas, other C1 - C15 hydrocarbons, and mixtures thereof. In some embodiments, the containment agent comprises water. In some 10 embodiments, the second well produces the containment agent. In some embodiments, the second well produces the containment agent, the miscible enhanced oil recovery formulation, and oil and/or gas. In one embodiment of the invention, there is disclosed a method for producing oil and/or gas comprising injecting a carbon disulfide formulation into a formation from 15 a first well; producing oil and/or gas from the formation from a second well; and injecting a containment agent into the formation from a plurality of containment wells. In some embodiments, the method also includes recovering carbon disulfide formulation from the oil and/or gas, if present, and then injecting at least a portion of the recovered carbon disulfide formulation into the formation. In some embodiments, 20 injecting the carbon disulfide formulation comprises injecting at least a portion of the carbon disulfide formulation into the formation in a mixture with one or more of hydrocarbons; sulfur compounds other than carbon disulfide; carbon dioxide; carbon monoxide; or mixtures thereof. In some embodiments, the method also includes heating the carbon disulfide formulation prior to injecting the carbon disulfide 25 formulation into the formation, or while within the formation. In some embodiments, the carbon disulfide formulation is injected at a pressure from 0 to 37,000 kilopascals above the initial reservoir pressure, measured prior to when carbon disulfide injection begins. In some embodiments, the underground formation comprises a permeability from 0.0001 to 15 Darcies, for example a permeability from 0.001 to 1 Darcy. In 30 some embodiments, any oil, as present in the underground formation prior to the injecting the carbon disulfide formulation, has a sulfur content from 0.5% to 5%, for 16 WO 2010/009118 PCT/US2009/050530 example from 1% to 3%. In some embodiments, the method also includes converting at least a portion of the recovered oil and/or gas into a material selected from the group consisting of transportation fuels such as gasoline and diesel, heating fuel, lubricants, chemicals, and/or polymers. 5 In one embodiment of the invention, there is disclosed a method for producing oil and/or gas comprising injecting a miscible enhanced oil recovery formulation into a formation from a first well; producing oil and/or gas from the formation from a second well; and injecting a containment agent into the formation from plurality of containment wells. In some embodiments, the method also includes injecting an 10 immiscible enhanced oil recovery formulation after injecting the miscible enhanced oil recovery formulation, to push the miscible enhanced oil recovery formulation through the formation. In some embodiments, the miscible enhanced oil recovery formulation comprises a carbon disulfide formulation. Those of skill in the art will appreciate that many modifications and variations 15 are possible in terms of the disclosed embodiments of the invention, configurations, materials and methods without departing from their spirit and scope. Accordingly, the scope of the claims appended hereafter and their functional equivalents should not be limited by particular embodiments described and illustrated herein, as these are merely exemplary in nature. 20 17

Claims

1. A system for producing oil or gas from an underground formation comprising: an enhanced oil recovery formulation comprising carbon disulfide, wherein the enhanced oil recovery formulation is miscible with oil; 5 a first well in the formation; a mechanism to inject the enhanced oil recovery formulation into the first well; a second well in the formation; a mechanism to produce oil or gas from the second well; wherein the first well and the second well comprise an interior of the system; lo a plurality of containment wells exterior to the first well and the second well; and a mechanism to inject a containment agent into the containment wells.

2. The system of claim 1, wherein the first well is at a distance of 10 meters to 1 kilometer from the second well.

3. The system of claim 1 or 2, wherein the underground formation is beneath a body of water. is

4. The system of any one of claims 1-3, further comprising a mechanism for injecting an immiscible enhanced oil recovery formulation into the formation, after the miscible enhanced oil recovery formulation has been released into the formation.

5. The system of any one of claims 1-4, wherein the enhanced oil recovery formulation further comprises a compound selected from the group consisting of hydrogen sulfide, carbon 20 dioxide, octane, LPG, C2-C6 aliphatic hydrocarbons, nitrogen, solvent, kerosene, acetone, xylene, thchloroethane, and mixtures thereof.

6. The system of any one of claims 1-5, further comprising an immiscible enhanced oil recovery formulation selected from the group consisting of water in gas or liquid form, air, and mixtures thereof; and a mechanism for injecting the immiscible enhanced oil recovery 25 formulation into the first well.

7. The system of any one of claims 1-6, further comprising a first array of wells comprising from 5 to 500 wells, and a second array of wells comprising from 5 to 500 wells. 19

8. The system of any one of claims 1-7, further comprising a mechanism for producing a carbon disulfide formulation.

9. The system of any one of claims 1-8, wherein the underground formation comprises an oil having a viscosity from 100 to 5,000,000 centipoise. s

10. The system of any one of claims 1-9, wherein the first well comprises a miscible enhanced oil recovery formulation profile in the formation, and the second well comprises an oil recovery profile in the formation, the system further comprising an overlap between the miscible enhanced oil recovery formulation profile and the oil recovery profile.

11. The system of any one of claims 1-10, wherein the containment agent is selected from the 10 group consisting of a refrigerant, water, brine, peroxide, peroxide solutions, nitrogen, air, carbon dioxide, natural gas, other CI-C 15 hydrocarbons, and mixtures thereof.

12. The system of claim 11, wherein the containment agent comprises water.

13. The system of any one of claims 1-12, wherein the second well produces the containment agent. 15

14. The system of any one of claims 1-13, wherein the second well produces the containment agent, the miscible enhanced oil recovery formulation, and oil or gas.

15. A method for producing oil or gas comprising: injecting a carbon disulfide formulation into a formation from a first well; producing oil or gas from the formation from a second well; and 20 injecting a containment agent into the formation from a plurality of containment wells.

16. The method of claim 15, further comprising recovering carbon disulfide formulation from the oil or gas, and then injecting at least a portion of the recovered carbon disulfide formulation into the formation.

17. The method of claim 15 or 16, wherein injecting the carbon disulfide formulation 25 comprises injecting at least a portion of the carbon disulfide formulation into the formation in a 20 mixture with one or more of hydrocarbons; sulfur compounds other than carbon disulfide; carbon dioxide; carbon monoxide; or mixtures thereof.

18. The methods of any one of claims 15-17, further comprising heating the carbon disulfide formulation prior to injecting the carbon disulfide formulation into the formation, or while within s the formation.

19. The method of any one of claims 15-18, wherein the carbon disulfide formulation is injected at a pressure from 0 to 37,000 kilopascals above the initial reservoir pressure, measured prior to when carbon disulfide injection begins.

20. The method of any one of claims 15-19, wherein the underground formation comprises a 1o permeability from 0.0001 to 15 Darcies.

21. The method of any one claims 15-20, wherein any oil, as present in the underground formation prior to the injecting the carbon disulfide formulation, has a sulfur content from 0.5% to 5%.

22. The method of any one of claims 15-2 1, further comprising converting at least a portion of is the recovered oil or gas into a material selected from the group consisting of transportation fuels, heating fuel, lubricants, chemicals, and polymers.

23. A method for producing oil or gas comprising: injecting an oil recovery formulation that is miscible with oil into an oil-bearing formation from a first well; 20 producing oil or gas from the formation from a second well; and injecting a containment agent into the formation from plurality of containment wells.

24. The method of claim 23, further comprising: injecting an immiscible enhanced oil recovery formulation after injecting the miscible enhanced oil recovery formulation, to push the miscible enhanced oil recovery formulation through the formation.

25 25. A system as claimed in claim 1, substantially as hereinbefore described with reference to any one of the accompanying drawings. 21

26. A method as claimed in claim 15 or 23, substantially as hereinbefore described with reference to any one of the accompanying drawings.

27. Oil or gas produced by the method of any one of claims 15 to 24 or 26. Dated 3 September 2012 5 Shell Internationale Research Maatschappij B.V. Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON