HYDROCARBON RESERVOIR TREATMENT METHOD WITH HYDROCARBONS
A hydrocarbon well treatment fluid is made recyclable by introducing a laminar flow enhancer into the fluid, resulting in a formulation called Slick Oil™ hydrocarbon fluid. A method of using a fluid in the treatment of a hydrocarbon reservoir is disclosed. A hydrocarbon fluid is injected into the hydrocarbon reservoir, the hydrocarbon fluid comprising hydrocarbons and a hydrophobic laminar flow enhancer. The hydrocarbon fluid is recovered from the hydrocarbon reservoir. The recovered hydrocarbon fluid is then cleaned by removing contaminants from the recovered hydrocarbon fluid that have been introduced into the hydrocarbon fluid from the hydrocarbon reservoir. The hydrocarbon fluid is then re-used by injecting the cleaned and recovered hydrocarbon fluid into at least one subsequent hydrocarbon reservoir. Proppant carrying abilities of a hydrocarbon fracturing fluid are enhanced by introducing a laminar flow enhancer into the fluid, resulting in a formulation called Slick Oil™ hydrocarbon fluid.
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Treatment of hydrocarbon reservoirs to enhance production.
BACKGROUNDProduction may be increased from a hydrocarbon reservoir by fracturing the reservoir with hydraulic fluid. Water is often used as the hydraulic fluid since it is inexpensive. However, water tends to damage, and may reduce production from, hydrocarbon reservoirs. Hydrocarbon fluids may also be used for hydraulic fracturing since hydrocarbon fluids tend to cause less formation damage, but hydrocarbon fluids are considerably more expensive than water in many locations, such as for example North America. An inexpensive method of fracturing a hydrocarbon reservoir with hydrocarbon is required.
Fractures caused by fracturing may be kept open by introducing particulates known as proppant into the hydrocarbon reservoir along with the hydraulic fluid. Liquefied petroleum gas may be advantageously used as the hydraulic fluid, but causing the liquefied petroleum gas to carry sufficient proppant may introduce other problems, such as recovery and disposal of a gellant used to increase the viscosity of the hydraulic fluid. A novel method of fracturing a hydrocarbon reservoir with hydrocarbon fluid is required.
SUMMARYIn an embodiment, a hydrocarbon well treatment fluid is made recyclable by introducing a laminar flow enhancer into the fluid, resulting in a formulation called Slick Oil™ hydrocarbon fluid.
In a further embodiment, proppant carrying abilities of a hydrocarbon fracturing fluid are enhanced by introducing a laminar flow enhancer into the fluid, resulting in a formulation called Slick Oil™ hydrocarbon fluid.
Also, a method of using a fluid in the treatment of a hydrocarbon reservoir is disclosed. A hydrocarbon fluid is injected into the hydrocarbon reservoir, the hydrocarbon fluid comprising hydrocarbons and a hydrophobic laminar flow enhancer. The hydrocarbon fluid is recovered from the hydrocarbon reservoir. The recovered hydrocarbon fluid is then cleaned by removing contaminants from the recovered hydrocarbon fluid that have been introduced into the hydrocarbon fluid from the hydrocarbon reservoir. The hydrocarbon fluid is then re-used by injecting the cleaned and recovered hydrocarbon fluid into at least one subsequent hydrocarbon reservoir.
A method of using a fluid in the treatment of a hydrocarbon reservoir is also disclosed. A hydrocarbon fluid is injected into the hydrocarbon reservoir, the hydrocarbon fluid comprising hydrocarbons and a hydrophobic laminar flow enhancer. The hydrocarbon fluid is then recovered from the hydrocarbon reservoir.
A method is also disclosed comprising cleaning a hydrocarbon fluid that has been injected into and subsequently recovered from a hydrocarbon reservoir during a treatment of the hydrocarbon reservoir, the cleaning comprising removing contaminants from the recovered hydrocarbon fluid that have been introduced into the hydrocarbon fluid from the hydrocarbon reservoir, the hydrocarbon fluid comprising hydrocarbons and a hydrophobic laminar flow enhancer.
A method of re-using a hydrocarbon fluid previously used in a treatment of a hydrocarbon reservoir during which the hydrocarbon fluid was injected into and subsequently recovered from the hydrocarbon reservoir and cleaned to remove contaminants introduced into the hydrocarbon fluid from the hydrocarbon reservoir, is also disclosed. The method comprises injecting the cleaned and recovered hydrocarbon fluid into at least one subsequent hydrocarbon reservoir, the hydrocarbon fluid comprising hydrocarbons and a hydrophobic laminar flow enhancer.
In some embodiments of the methods disclosed herein, the hydrocarbon fluid excludes liquefied petroleum gas. In other embodiments of the methods disclosed herein, the hydrocarbon fluid comprises liquefied petroleum gas.
In another embodiment, there is provided apparatus for treating hydrocarbon fluid recovered from a well.
A method of using a fluid in the treatment of a hydrocarbon reservoir is also disclosed. A hydrocarbon fluid is injected into the hydrocarbon reservoir, the hydrocarbon fluid comprising liquefied petroleum gas and a laminar flow enhancer. Pressure is applied to the hydrocarbon fluid injected into the hydrocarbon reservoir.
These and other aspects of the device and method are set out in the claims, which are incorporated here by reference.
Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which:
Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.
Laminar flow enhancers may be added to oil, in order to allow the oil to go down a pipeline faster and easier. The flow enhancer operates by allowing the oil to move in a more laminar flow, thus reducing turbulence. These characteristics reduce the drag and friction between the oil and the pipeline, thus reducing the pressure required to pump the oil. Laminar flow enhancers may be polymers, for example polymerized hydrocarbons, thus adding viscosity to the hydrocarbon fluid, which reduces the turbulence induced as the fluid flows. Reductions in fluid friction of 50 to 60% are possible. Laminar flow enhancers tend to lubricate the oil, making the oil travel in sheets as the polymers slide in relation to one another, which results in a reduction or elimination of turbulent flow. Examples of hydrophobic flow enhancers include OFR-2 by Weatherford.
The laminar flow enhancer used in the embodiments herein may be hydrophobic. Hydrophilic laminar flow enhancers are less desirable, as they tend to absorb additional water from the formation, thus increasing the cost of cleaning the recovered hydrocarbon fluid. In addition, hydrophilic enhancers may plate out in the formation alongside formation water, thus plugging the pores of the formation. In some embodiments, the hydrophobic laminar flow enhancers disclosed herein do not plate out in the well or formation. In addition, the hydrophobic laminar flow enhancer may be a non-emulsifier, thus allowing any water absorbed into the hydrocarbon fluid from the hydrocarbon reservoir to be easily removable. The hydrophobic laminar flow enhancer may be used in very low concentration, such as less than 0.5-1% for example. At sufficiently low concentrations, the enhancer is not required to be listed on the MSDS of the fluid. In some embodiments, the hydrophobic flow enhancer may be easily removable from the hydrocarbon fluid. An example of a hydrocarbon fluid that has all of these characteristics is Slick Oil™ fluid supplied by SynOil Fluids of Calgary, Alberta, Canada. Slick Oil™ fluid will absorb very little measurable water during a downhole treatment. Examples of suitable hydrophobic flow enhancers include those disclosed in U.S. Pat. No. 6,395,852, and OFR-2 (Weatherford). In some embodiments, the hydrophobic laminar flow enhancer comprises a friction reducer. An example of such a hydrophobic laminar flow enhancer is EC6507A, made by Nalco.
A further embodiment of a hydrophobic flow enhancer that comprises a friction reducer is UFV-100, available from Uniquem Inc., 240 Everwillow Green SW, Calgary, AB, T2Y 4V9. UFV-100 is advantageous because it is imparts additional viscosity to the hydrocarbon fluid. UFV-100 is shown in the Table 1 below as being added in, for example, amounts of 0.5 to 5.5 liters/m3 of the hydrocarbon fluid to get sufficient viscosity to carry proppant. In Table 1, the frac oils (hydrocarbon fluid) used were obtained from Synoil fluids in Calgary, AB. Referring to
Referring to
Referring to
In a stage 52 (shown in
In a stage 54 (shown in
De-watered hydrocarbon fluid is then passed from unit 68 into line 84 into a vapor removal unit 28. Unit 28 may be designed to remove volatile contaminants by for example heating the recovered hydrocarbon fluid. In some embodiments, sufficient volatile components are removed to cause the recovered hydrocarbon fluid to have a flash point greater than 10° C. and a Reid vapor pressure of at least 2 psi. In some embodiments, the Reid vapor pressure is 4 kPa. In other embodiments, sufficient volatiles are removed to meet the local regulations as required. This may be accomplished by heating the hydrocarbon fluid (indicated by reference numeral 30) using heating coil 32 as shown, which may for example be any of various types of heaters, such as a conduit carrying heated fluid. An exemplary treatment may comprise heating the recovered hydrocarbon fluid to 80 degrees C. for 15 minutes with a ramp up and ramp down. This may remove any C5 and under hydrocarbons, for example. In some embodiments, a vacuum may be applied, via line 82 for example, to the recovered hydrocarbon fluid to remove the volatile components. The line 82 may be connected to a pump or other vacuum source 83, and the pump or other vacuum source 83 may pump vapors out to a vapor disposal unit 85, such as a flare or vapor recovery system.
Once sufficient volatiles are removed, the partially cleaned hydrocarbon fluid is then passed via line 36 into a solids removal unit 38. Unit 38 may comprise at least one filter 42, for example, for removing solid particles. The filtering of the recovered hydrocarbon fluid may comprise removing particles greater than 1 μm in diameter, for example. The filtered solid particles are illustrated by reference numeral 40 for example.
In some embodiments, the oil-water separator, the vapor removal unit and the solids removal unit are connected together for sequential processing of the hydrocarbon fluid to clean the hydrocarbon fluid for subsequent re-use. It should be understood that, during the cleaning stage, the position of units 68, 28, and 38 in the process line may be interchanged or switched. For example, it may be beneficial to filter the hydrocarbon fluid prior to removing volatiles and water. In addition, other cleaning stages or units may be added as desired. Prior to cleaning, the cleaned and recovered hydrocarbon fluid may be passed from unit 38 via line 44 into, for example, a reservoir 46 for storage. In other embodiments, the cleaned and recovered hydrocarbon fluid may be passed back into reservoir 10 via line 49 for example. In further embodiments, the cleaned and recovered hydrocarbon fluid may be passed to a sales line. In some embodiments, the hydrocarbon fluid is at least partially cleaned. In addition, the units 68, 28 and 38 may be mounted together as a unit 81 for example on a trailer bed or skid 87 for mobile operation.
In a stage 56 (shown in
As disclosed above, in some embodiments, gelling agents may be used in the hydrocarbon fluid. However, in other embodiments, the hydrocarbon fluid excludes a gelling agent. Gelling agents tend to be hard to remove from hydrocarbon fluids, and may decrease the value of the hydrocarbon fluid when present. Spent gelling agents also present a clean-up cost required to make the hydrocarbon fluid ready for sale or further fracturing treatments. Gelling agents are also typically used in large concentrations, and absorb water while in the formation, further increasing clean-up costs. The presence of gelling agents, namely phosphorous containing gelling agents, have also been identified as the causes of extensive complications in downstream facilities, where certain varieties are known to plug distillation trays and shut down refineries.
The hydrophobic laminar flow enhancer allows large amounts of proppant to be carried downhole in the hydrocarbon fluid, and thus a gelling agent may not be required. This represents a huge technical advantage, namely when LPG fluids are used, because this overcomes the limitation of the relatively small proppant volumes usable with conventional LPG systems, as the amount of proppant that can be pumped with the LPG is greatly increased.
Referring to
Referring to
Referring to
In some embodiments, the hydrocarbon fluid excludes liquefied petroleum gas. Excluding may refer to there being less than 1% of the excluded component present. In other embodiments, excluding may refer to there being less than 0.1 or 0.01% of the excluded component present. In other embodiments, the hydrocarbon fluid comprises liquefied petroleum gas. LPG is advantageous, since it may be vaporized and easily removed from hydrocarbon reservoir 24 during treatment.
Referring to
In some embodiments, the fracture treatment may combine a hydrocarbon fluid excluding LPG and a hydrocarbon fluid comprising LPG. For example, the treatment may combine a gelled LPG stream with proppant and a non-gelled stabilized hydrocarbon liquid with proppant which may be friction reduced. Friction reduction chemicals may be purchased commercially.
It should be understood that the methods disclosed herein may have various steps added to them, for example, adding repetition steps. For further example, the method disclosed in
In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.
Claims
1. A method of using a fluid in the treatment of a hydrocarbon reservoir, the method comprising:
- injecting a hydrocarbon fluid into the hydrocarbon reservoir, the hydrocarbon fluid comprising hydrocarbons and a hydrophobic laminar flow enhancer;
- recovering the hydrocarbon fluid from the hydrocarbon reservoir;
- cleaning the recovered hydrocarbon fluid by removing contaminants from the recovered hydrocarbon fluid that have been introduced into the hydrocarbon fluid from the hydrocarbon reservoir; and
- re-using the hydrocarbon fluid by injecting the cleaned and recovered hydrocarbon fluid into at least one subsequent hydrocarbon reservoir.
2. The method of claim 1 in which the at least one subsequent hydrocarbon reservoir comprises the hydrocarbon reservoir.
3. The method of claim 1 in which the at least one subsequent hydrocarbon reservoir comprises a second hydrocarbon reservoir.
4. The method of claim 1 further comprising applying pressure to the hydrocarbon fluid injected into the hydrocarbon reservoir.
5. The method of claim 4 in which the pressure is sufficient to cause fracturing of the hydrocarbon reservoir.
6. The method of claim 1 in which re-using further comprises applying pressure to the cleaned and recovered hydrocarbon fluid injected into the subsequent hydrocarbon reservoir.
7. The method of claim 6 in which the pressure applied to the cleaned and recovered hydrocarbon fluid injected into the subsequent hydrocarbon reservoir is sufficient to cause fracturing of the subsequent hydrocarbon reservoir.
8. The method of claim 1 in which removing contaminants comprises removing solid particles.
9. The method of claim 8 in which removing solid particles comprises filtering.
10. The method of claim 9 in which filtering of the recovered hydrocarbon fluid comprises removing particles greater than 1 μm in diameter.
11. The method of claim 1 in which removing contaminants comprises heating the recovered hydrocarbon fluid to remove volatile components.
12. The method of claim 11 in which sufficient volatile components are removed to cause the recovered hydrocarbon fluid to have a flash point greater than 10° C. and a Reid vapour pressure of at least 2 psi.
13. The method of claim 1 in which removing contaminants comprises applying a vacuum to the recovered hydrocarbon fluid to remove volatile components.
14. The method of claim 1 in which removing contaminants comprises removing water from the recovered hydrocarbon fluid.
15. The method of claim 14 in which removing water comprises one or more of decanting, centrifuging, skimming, and drying.
16. The method of claim 1 in which the hydrophobic laminar flow enhancer comprises a polymerized hydrocarbon.
17. The method of claim 1 in which the hydrocarbon fluid is initially injected into the hydrocarbon reservoir with proppant.
18. The method of claim 1 in which the hydrophobic laminar flow enhancer is present in an amount of less than 1% by weight of the hydrocarbon fluid.
19. The method of claim 1 in which the hydrocarbon fluid is injected into the hydrocarbon reservoir along with a drive fluid.
20. The method of claim 19 in which the drive fluid comprises carbon dioxide, liquefied petroleum gas, or nitrogen.
21. The method of claim 1 in which hydrophobic laminar flow enhancer is added to the recovered and cleaned hydrocarbon fluid before or during re-use of the recovered and cleaned hydrocarbon fluid.
22-29. (canceled)
30. The method of claim 1 in which the hydrocarbon fluid excludes a is free of gelling agent.
31. The method of claim 1 in which the hydrocarbon fluid excludes is free of liquefied petroleum gas.
32. The method of claim 1 in which the hydrocarbon fluid comprises liquefied petroleum gas.
33-36. (canceled)
37. A method of using a fluid in the treatment of a hydrocarbon reservoir, the method comprising:
- injecting a hydrocarbon fluid into the hydrocarbon reservoir, the hydrocarbon fluid comprising liquefied petroleum gas and a laminar flow enhancer; and
- applying pressure to the hydrocarbon fluid injected into the hydrocarbon reservoir.
38. The method of claim 37 in which the pressure applied to the hydrocarbon fluid is sufficient to cause fracturing of the hydrocarbon reservoir.
39. The method of claim 37 in which the hydrocarbon fluid further comprises C6+ hydrocarbon fluid.
40. The method of claim 39 in which the C6+ hydrocarbon fluid is combined with laminar flow enhancer and then mixed with liquefied petroleum gas prior to injection into the well.
41-48. (canceled)
49. The method of claim 1 in which the hydrocarbons comprise liquefied petroleum gas.
Type: Application
Filed: Oct 23, 2009
Publication Date: Jun 3, 2010
Applicant: SYNOIL FLUIDS HOLDINGS INC. (Calgary)
Inventor: John Edwards (Calgary)
Application Number: 12/605,235
International Classification: E21B 43/16 (20060101); E21B 21/06 (20060101);