CN112324411A - Loose sandstone heavy oil reservoir vertical well complex long-seam fracturing process - Google Patents
Loose sandstone heavy oil reservoir vertical well complex long-seam fracturing process Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 63
- 230000008569 process Effects 0.000 title claims abstract description 55
- 239000000295 fuel oil Substances 0.000 title claims abstract description 31
- 239000004576 sand Substances 0.000 claims abstract description 66
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 55
- 239000012530 fluid Substances 0.000 claims abstract description 51
- 230000001965 increasing effect Effects 0.000 claims abstract description 26
- 239000007788 liquid Substances 0.000 claims abstract description 24
- 239000000835 fiber Substances 0.000 claims abstract description 19
- 238000006073 displacement reaction Methods 0.000 claims abstract description 11
- 239000003921 oil Substances 0.000 claims description 27
- 239000002245 particle Substances 0.000 claims description 26
- 238000002347 injection Methods 0.000 claims description 12
- 239000007924 injection Substances 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 238000004132 cross linking Methods 0.000 claims description 7
- ZRALSGWEFCBTJO-UHFFFAOYSA-N Guanidine Chemical compound NC(N)=N ZRALSGWEFCBTJO-UHFFFAOYSA-N 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- 239000004927 clay Substances 0.000 claims description 5
- 239000003129 oil well Substances 0.000 claims description 5
- 229920000642 polymer Polymers 0.000 claims description 5
- 239000003381 stabilizer Substances 0.000 claims description 5
- 230000000844 anti-bacterial effect Effects 0.000 claims description 4
- 239000003899 bactericide agent Substances 0.000 claims description 4
- CHJJGSNFBQVOTG-UHFFFAOYSA-N N-methyl-guanidine Natural products CNC(N)=N CHJJGSNFBQVOTG-UHFFFAOYSA-N 0.000 claims description 3
- 239000000654 additive Substances 0.000 claims description 3
- 230000000996 additive effect Effects 0.000 claims description 3
- SWSQBOPZIKWTGO-UHFFFAOYSA-N dimethylaminoamidine Natural products CN(C)C(N)=N SWSQBOPZIKWTGO-UHFFFAOYSA-N 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 229910021538 borax Inorganic materials 0.000 claims description 2
- 239000003599 detergent Substances 0.000 claims description 2
- 239000002736 nonionic surfactant Substances 0.000 claims description 2
- 239000004328 sodium tetraborate Substances 0.000 claims description 2
- 235000010339 sodium tetraborate Nutrition 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 4
- 238000011084 recovery Methods 0.000 abstract description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 51
- 238000010276 construction Methods 0.000 description 15
- 239000000499 gel Substances 0.000 description 15
- 238000004519 manufacturing process Methods 0.000 description 14
- 235000015110 jellies Nutrition 0.000 description 9
- 239000008274 jelly Substances 0.000 description 9
- 238000013461 design Methods 0.000 description 7
- 238000009472 formulation Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 230000004048 modification Effects 0.000 description 6
- 238000012986 modification Methods 0.000 description 6
- 238000005086 pumping Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000010779 crude oil Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 2
- 230000002579 anti-swelling effect Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 229920013818 hydroxypropyl guar gum Polymers 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229920002907 Guar gum Polymers 0.000 description 1
- 239000006004 Quartz sand Substances 0.000 description 1
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 1
- 150000003863 ammonium salts Chemical group 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009933 burial Methods 0.000 description 1
- -1 carboxymethyl hydroxypropyl Chemical group 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 1
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 description 1
- 239000000665 guar gum Substances 0.000 description 1
- 229960002154 guar gum Drugs 0.000 description 1
- 235000010417 guar gum Nutrition 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 150000003384 small molecules Chemical class 0.000 description 1
- ANOBYBYXJXCGBS-UHFFFAOYSA-L stannous fluoride Chemical compound F[Sn]F ANOBYBYXJXCGBS-UHFFFAOYSA-L 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/602—Compositions for stimulating production by acting on the underground formation containing surfactants
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/605—Compositions for stimulating production by acting on the underground formation containing biocides
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- C—CHEMISTRY; METALLURGY
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- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/607—Compositions for stimulating production by acting on the underground formation specially adapted for clay formations
- C09K8/608—Polymer compositions
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- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/62—Compositions for forming crevices or fractures
- C09K8/66—Compositions based on water or polar solvents
- C09K8/68—Compositions based on water or polar solvents containing organic compounds
- C09K8/685—Compositions based on water or polar solvents containing organic compounds containing cross-linking agents
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- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/84—Compositions based on water or polar solvents
- C09K8/86—Compositions based on water or polar solvents containing organic compounds
- C09K8/88—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
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- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/84—Compositions based on water or polar solvents
- C09K8/86—Compositions based on water or polar solvents containing organic compounds
- C09K8/88—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
- C09K8/90—Compositions based on water or polar solvents containing organic compounds macromolecular compounds of natural origin, e.g. polysaccharides, cellulose
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/261—Separate steps of (1) cementing, plugging or consolidating and (2) fracturing or attacking the formation
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
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- C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
- C09K2208/12—Swell inhibition, i.e. using additives to drilling or well treatment fluids for inhibiting clay or shale swelling or disintegrating
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Abstract
The invention discloses a vertical well complex long-crack fracturing process of a unconsolidated sandstone heavy oil reservoir, which comprises the steps of firstly injecting high-viscosity fracturing fluid into a stratum for crack formation, and injecting liquid in batches according to an increasing sand ratio to complete one-time crack formation; after the sand adding is finished, reducing the discharge capacity and injecting a temporary plugging agent to plug the crack; then, the discharge capacity is increased, the net pressure of the cracks is increased, the cracks are forced to turn, and the crack forming process is repeated, wherein when the sand ratio is increased to 50-70%, the self-dispersing degradable fibers are added in a tail-chasing mode; and finally fracturing the displacement fluid. Aiming at the characteristics of a unconsolidated sandstone reservoir, the conventional pre-filling fracturing sand control process is converted into a high-flow-guide complex long-crack fracturing process, and the measures of high sand ratio, large liquid volume, combined temporary plugging agent, combined propping agent, fiber combined filling crack and the like are combined, after the high-flow-guide long crack is formed for the first time, the temporary plugging agent is used for plugging the conventional crack, and the crack is forced to turn again, so that the long crack is formed, the fracturing effect of effectively improving the volume and effectively controlling the sand control is increased, and the recovery ratio of a unconsolidated sandstone heavy oil reservoir is remarkably improved.
Description
Technical Field
The invention belongs to the technical field of oil and gas field exploration and development, and particularly relates to a straight well complex long-seam fracturing process for a unconsolidated sandstone heavy oil reservoir.
Background
For the fracturing of a loose sandstone heavy oil reservoir, the most common production increasing process at home and abroad at present is end desanding fracturing, and short and wide fractures are formed in the reservoir, so that the fracture conductivity is improved, and the purpose of increasing the production is achieved. However, with the continuous development of the octahedral river loose sandstone reservoir, the process has the following defects: 1) the process mainly forms short and wide fractures with high diversion in a near wellbore area in a reservoir, the modification volume is limited, the effect is obvious in the initial modification period, but the problem that the productivity is reduced quickly in a short time exists; 2) the unconsolidated sandstone heavy oil reservoir is shallow in burial, is cemented and loosely fractured, is thick in oil, and is easy to produce sand after fracturing, and the pre-filling fracturing provides an oil flow channel for the reservoir, but the sand production problem still exists in the production process, so that the yield is reduced.
Disclosure of Invention
The invention mainly aims to solve the problems that the yield of the conventional octahedral river loose heavy oil reservoir is reduced quickly after fracturing and pre-filling, sand is easy to generate, the effective period of measures is short, the single well productivity is influenced and the like, and provides a fracturing method for a straight well complex long-crack fracturing process of the loose sandstone heavy oil reservoir; according to the characteristics of a reservoir of the unconsolidated sandstone heavy oil reservoir, the conventional pre-filling fracturing sand control process is converted into a high-flow-guide long-seam fracturing process, the fracture is filled by using a high sand ratio, a large liquid amount, temporary plugging agent combinations with different particle sizes and propping agent combinations with different particle sizes, after the high-flow-guide long seam is formed for the first time, the existing fracture is plugged by using the temporary plugging agent, and the fracture is forced to turn again, so that the success of the fracturing process aiming at making the long seam and increasing the effective reconstruction volume is ensured, and the single-well productivity of the unconsolidated sandstone heavy oil reservoir is.
In order to achieve the purpose, the invention adopts the technical scheme that:
a loose sandstone heavy oil reservoir straight well complex long seam fracturing process comprises a primary high diversion long seam building process, a temporary plugging process, a secondary steering high diversion long seam building process and a fracturing displacement fluid process, and specifically comprises the following steps:
making high-flow-guide long cracks at one time, injecting high-viscosity fracturing fluid into the unconsolidated strata to make cracks, and then injecting the fracturing fluid carrying small-particle-size proppant into the unconsolidated strata in batches according to the sequentially increasing low sand ratio; then, carrying out fractional injection on the fracturing fluid carrying the large-particle-size proppant according to sequentially increasing high sand ratios to finish primary fracturing;
2) temporary plugging process, namely reducing the discharge volume and injecting a temporary plugging agent into the joint after sand adding is finished;
3) turning for the second time to make a high-flow-guide long seam, lifting the discharge capacity to the condition in the step 1), repeating the seam making process in the step 1), and adding self-dispersing degradable fibers in a high sand ratio stage;
4) and (4) fracturing the displacement fluid, calculating the using amount of active water according to the lower deep volume of the oil well measure pipe column after the sand adding is finished, and replacing by adopting the active water.
In the scheme, the low sand ratio is 10-40%, and the high sand ratio is 50-80%; the sand ratio increasing amplitude is 5-10%.
Preferably, the surface modified self-dispersing degradable fiber is added in a tail-end mode when the sand ratio is 50-70%.
In the scheme, the discharge capacity of the fracturing fluid in the step 1) and the step 3) is 4-5m3Min, the discharge amount of the temporary plugging agent in the step 2) is 1-2m3/min。
In the above scheme, the fracturing fluid comprises a base fluid and a cross-linking fluid, wherein the base fluid comprises the following components in percentage by mass: 0.35-0.5% of guanidine gum, 0.012-0.015% of NaOH, 0.2-0.5% of cleanup additive, 1.0-2.0% of clay stabilizer, 0.3-0.5% of oil detergent, 0.01-0.02% of bactericide and the balance of water; the cross-linking liquid comprises the following components in percentage by mass: 0.8-1% of borax, 0.3-0.5% of gel breaker and the balance of water; the crosslinking ratio is 100 (4-5).
In the scheme, the guar gum can be hydroxypropyl guar gum, carboxymethyl hydroxypropyl guar gum and the like.
In the scheme, the cleanup additive can be JW-201 or fluorocarbon surfactant and the like.
In the above embodiment, the clay stabilizer may be JC-NW2, a small molecule polyquaternary ammonium salt clay stabilizer, or the like.
In the scheme, the bactericide can be JC-SJ2 or aldehyde bactericide and the like.
In the scheme, the oil washing agent can be selected from a nonionic surfactant such as AE 1910.
In the scheme, the gel breaker can be selected from ammonium persulfate and the like.
Aiming at the lithology characteristics of the physical properties of the reservoir of the unconsolidated sandstone heavy oil reservoir in the octahedral river oil field, selecting a guanidine gum fracturing fluid system, wherein the viscosity of a base fluid is 25-40mPa & s, the viscosity of cross-linked jelly is 150-200mPa & s, and the viscosity of a gel breaking fluid is 2-3.3mPa & s; the fracturing fluid has the characteristics of low surface tension, high efficiency, anti-swelling, strong oil washing, strong sand carrying, less residue, easy gel breaking and easy flowback,
in the scheme, the size of the small-particle size proppant is 30-60 meshes, and the size of the large-particle size proppant is 20-40 meshes; determining an optimal combination mode that the volume ratio of the small-particle size proppant to the large-particle size proppant is 1:3 according to the particle size of the sandstone returned from the site and by combining a conductivity test; the test results show that the combination still has high conductivity when 10% return sand grains are contained.
In the scheme, the propping agent can be selected from ceramsite, quartz sand, coated sand and the like.
In the scheme, the temporary plugging agent is a water-soluble alcohol polymer, can play a plugging role at the formation temperature to implement steering, and can meet the formation temperature; and the paint can be completely dissolved in the construction time, and the dissolved liquid has no residue and little harm to a reservoir stratum.
In the scheme, in the temporary plugging process, the using amount of the temporary plugging agent is calculated according to the size of the previous fracture, and is obtained by comprehensive calculation mainly considering the length, width and height of the fracture, the porosity and the density of the temporary plugging agent; the size of the temporary plugging agent is determined according to the previous fracturing fracture, the size of the temporary plugging agent is 4-120 meshes, a large-medium-small particle size combination mode is preferably adopted, and the preferred combination ratio is 1:3:1 (volume ratio).
In the scheme, the self-dispersing degradable fiber is a water-soluble alcohol polymer; adding the fiber with the concentration of 0.3-0.7 wt%; the net structure formed by the fibers and the proppant is adopted, and sand production is further controlled on the basis of sand prevention of the combined proppant.
The invention provides a vertical well complex long crack fracturing process of a unconsolidated sandstone heavy oil reservoir by researching the fracturing, cracking and steering mechanisms of the unconsolidated sandstone oil reservoir: according to the reservoir characteristics of the unconsolidated sandstone heavy oil reservoir, the conventional pre-filling fracturing sand control process is converted into a high-flow-guide complex long-seam fracturing process, the measures of high sand ratio, large liquid volume, combined temporary plugging agent, combined propping agent and fiber combined filling of the fracture and the like are combined, after the high-flow-guide long seam is formed for the first time, the temporary plugging agent is used for plugging the existing fracture, the fracture is forced to turn again to realize the long seam construction, the effective reconstruction volume is increased, the fracturing effect of sand control is effectively controlled, and the recovery ratio of the unconsolidated sandstone heavy oil reservoir is remarkably improved.
Compared with the prior art, the invention has the beneficial effects that:
1) the invention provides a multifunctional fracturing fluid system for the first time, and a wash oil agent and a self-developed long-acting anti-swelling agent are added into a thick oil fracturing fluid formula, so that the damage to a reservoir bed caused by long-term retention of the fracturing fluid at the bottom of a well is reduced, the wash oil agent and crude oil generate a chemical reaction, the viscosity of the crude oil at the bottom of the well is reduced, and the fluidity of the crude oil is improved, thereby improving the single-well productivity;
2) the invention firstly provides a fracturing process for replacing a pre-filled sand-prevention near-wellbore zone to form a short and wide seam in a vertical well of a loose sandstone heavy oil reservoir by a complex long seam fracturing process, a high-flow-guide long oil flow channel is formed by utilizing the improvement of the pre-liquid amount to make the long seam combined proppant to be fully filled with sand, the oil drainage area is increased, and the fracturing modification volume is enlarged by utilizing the inward turning of a water-soluble temporary plugging agent seam, so that the yield-increasing multiple and the oil production speed of an oil well are further improved, and a brand new thought is provided for the fracturing process of the loose sandstone heavy oil reservoir;
3) the invention firstly proposes that a small amount of surface modified self-dispersing degradable fibers are added to support with different particle sizes by using the ultrahigh sand ratio and in the stage of the ultrahigh sand ratio to form a net-shaped and columnar structure, so that the flow conductivity of the crack is improved, a sealing sand-blocking barrier is effectively formed at the same time, the sand production of the stratum after pressing is prevented, and the water-soluble temporary plugging agent is used for realizing the steering expansion of the reconstruction volume in the crack; the stable production period and the recovery ratio of the medium-low permeability heavy oil reservoir can be obviously improved by the cooperation of a plurality of means;
4) the improved method is simple, high in success rate, wide in material source, high in universality, high in safety and reliability and convenient to operate; and the fracturing yield-increasing effect can be obviously improved, and the method has important economic and social benefits and is suitable for popularization and application.
Detailed Description
The present invention will be further described with reference to the following examples for better understanding, but the present invention is not limited to the following examples.
In the following examples, JW-201 was used as supplied by Guanyou chemical Co., Ltd, Binzhou; JC-NW2 is provided by the oil field oil engineering institute in Jianghan province; the adopted self-dispersing degradable fiber is a water-soluble alcohol polymer, the size of the self-dispersing degradable fiber is 3-12mm, and the self-dispersing degradable fiber is BF-II provided by Chengdu Lao Pusi science and technology limited company; the size of the adopted temporary plugging agent is 4-120 meshes, and is LP-WDB30 provided by Chengdu Lao Pusi science and technology Limited.
Example 1
A loose sandstone heavy oil reservoir vertical well large-scale complex long-fracture fracturing process is aimed at M14-10-X43 wells S of octahedral river oil field462The well adopts pre-filling fracturing twice in the earlier stage, and does not obtain a good yield increasing effect. The construction design liquid volume is 301.7m3The design amount of the 30/60-mesh ceramsite is 17m3The design amount of the 20/40-mesh ceramsite is 53m3Average sand ratio of 52.5% and discharge capacity of 5m3The adopted fracturing fluid formula and the pump injection procedure are respectively shown in the table 1 and the table 2, and the specific fracturing process comprises the following steps:
1) making high-flow-guide long seam at one time, firstly pressing with high-viscosity gel fracturing fluid according to 5m3Carrying out crack formation at the discharge amount of/min, carrying small-particle-size ceramsite (30/60-mesh ceramsite) by the gel fracturing fluid according to the low sand ratio of 10%, 20%, 30% and 40% in sequence for liquid injection (carrying liquid), then changing a large proppant (large-particle-size ceramsite), carrying large-particle-size ceramsite (20/40-mesh ceramsite) by the gel according to the high sand ratio of 50%, 60%, 70% and 80% in sequence for liquid injection, and completing primary fracturing;
2) temporary plugging process
The discharge capacity is reduced by 1-2m after the sand adding is finished3Injecting the temporary plugging agent at a discharge rate of 1.0 ton within 2-3min, and quickly increasing the discharge rate to 5m in real time according to the pressure rise condition of a construction curve in the adding process3/min；
3) Secondary steering high-flow-guiding long seam
Firstly, using high-viscosity jelly to press 5m3Filling gaps at a/min displacement, carrying small-particle-size ceramsite by gel according to low sand ratios of 15%, 25%, 30% and 40% in sequence for injection, then changing a propping agent to be large, carrying large-particle-size ceramsite by gel according to high sand ratios of 50%, 60%, 70% and 80% for injection, and adding self-dispersing degradable fibers after finishing when the sand ratio is 50-70%;
4) and in the stage of fracturing the displacement fluid, active water is used for displacement, and the using amount of the displacement fluid is calculated according to the lower deep volume of the oil well measure tubular column.
The formulations of the jelly and base solution used in the different stages of this example are shown in Table 1.
TABLE 1 fracturing fluid formulation
The present example is directed to a well depth of 1320m at a temperature of 60 ℃; the prepared jelly viscosity is 180 mPas, and the base liquid viscosity is 26 mPas.
After the formula and the amount of the fracturing fluid are determined, pumping the surface of the fracturing fluid, pumping the base fluid or the gel fluid according to the construction, and the formula and the amount are shown in the table 2.
TABLE 2M 14-10-X43 well Pumping program
In the table, the volume ratio of the small particle size proppant (ceramsite) to the large particle size proppant (ceramsite) was 1: 3; the using amount of the temporary plugging agent is calculated according to the size of the fracture in the previous fracturing, and the temporary plugging agent is obtained by comprehensive calculation mainly considering the length, width and height of the fracture, the porosity and the density of the temporary plugging agent; the size of the temporary plugging agent is determined according to the previous fracturing crack, the size of the temporary plugging agent is 4-120 meshes, a large-medium-small particle size combination mode is adopted, and the volume ratio of the large-particle size temporary plugging agent (6 meshes), the medium-particle size temporary plugging agent (10 meshes) and the small-particle size temporary plugging agent (120 meshes) is 1:3: 1.
Tests show that the embodiment adopts a large-scale high-diversion complex long-seam fracturing process, long seams are made by improving the amount of the preposed liquid, the gel is injected with the small-particle-size propping agent firstly, then the large-particle-size propping agent is injected, temporary plugging in the seams is realized by means of the temporary plugging agent to force the fractures to turn, fiber sand is added after the fractures, secondary sand control is carried out while high-diversion seepage channels are formed, the reconstruction volume is enlarged, the daily oil yield after the well is fractured is increased to 6.8t from 0.3t, the initial yield is exceeded, the daily liquid yield is increased to 15.0t from 3.2, the liquid supply capacity is greatly improved, and the stable production time is 300 days.
Example 2
A loose sandstone heavy oil reservoir vertical well large-scale complex long-fracture fracturing process is aimed at M14-12-X31 wells S of octahedral river oil field462The well adopts two times of pre-filling fracturing in the earlier stage, wherein the construction design liquid amount is 183.4m3The design amount of the 30/60-mesh ceramsite is 11m3The design quantity of the 20/40-mesh ceramsite is 34m3Average sand ratio of 49.3% and discharge capacity of 5m3The adopted fracturing fluid formula and pump injection procedure are respectively shown in tables 3 and 4, and the specific fracturing process comprises the following steps:
1) the high flow guide long seam is made at one time, and the gel fracturing fluid is firstly pressed according to the pressure of 5m3Discharging and forming cracks at a displacement of/min, carrying small-particle-size ceramic particles by the aid of gel fracturing fluid according to low sand ratios of 20%, 30% and 40% in sequence for injection, changing a propping agent into a large size, carrying large-particle-size ceramic particles by the aid of gel according to high sand ratios of 50%, 60%, 70% and 80% in sequence for injection, and completing primary fracturing;
2) temporary plugging process
The discharge capacity is reduced by 1-2m after the sand adding is finished3Injecting at a discharge rate of/min, adding 0.8 ton of temporary plugging agent within 2-4min, and quickly increasing the discharge rate to 5m in real time according to the pressure rise condition of a construction curve in the adding process3/min；
3) Secondary steering high-flow-guiding long seam
Firstly, cross-linked jelly is pressed by 5m3Filling gaps at a/min displacement, carrying small-particle-size ceramsite by the aid of jelly glue according to low sand ratios of 20%, 30% and 40% in sequence for injection, changing a propping agent into a larger size, carrying large-particle-size ceramsite by the jelly glue according to high sand ratios of 50%, 60%, 70% and 80% in sequence for injection, and adding self-dispersing degradable fibers when the sand ratio is 50-70%.
The formulations of the jelly and base solution used in the different stages of this example are shown in Table 3.
TABLE 3 fracturing fluid formulation
The examples are directed to wells with a depth of 1297m and a temperature of 58 ℃; the prepared jelly viscosity is 180 mPas, and the base liquid viscosity is 22 mPas.
After the formula and the amount of the fracturing fluid are determined, the surface is pumped according to the construction, and the base fluid or the gel liquid is pumped according to the construction, as shown in the table 4.
TABLE 4 Pumping program
In the table, the volume ratio of the small particle size proppant (ceramsite) to the large particle size proppant (ceramsite) was 1: 3; the using amount of the temporary plugging agent is calculated according to the size of the fracture in the previous fracturing, and the temporary plugging agent is obtained by comprehensive calculation mainly considering the length, width and height of the fracture, the porosity and the density of the temporary plugging agent; the size of the temporary plugging agent is determined according to the previous fracturing crack, the size of the temporary plugging agent is 4-120 meshes, a large-medium-small particle size combination mode is adopted, and the volume ratio of the large-particle size temporary plugging agent (6 meshes), the medium-particle size temporary plugging agent (10 meshes) and the small-particle size temporary plugging agent (120 meshes) is 1:3: 1.
After the large-scale complex long-crack fracturing process is adopted, the daily oil yield is increased from 1 to 6.0t, the initial yield is exceeded, and the daily fluid yield is increased from 2 to 12.1m3The liquid supply capacity is greatly improved, and the stable production time is 378 days.
Comparative example 1
At present, the octahedral river oil field is commonly constructed by a pre-filling fracturing technology and optimized construction parameters, an oil well M14-12-X35 is constructed by adopting low discharge capacity, small liquid amount and low sand ratio, the formula of the adopted gel fracturing fluid is shown in a table 5, and the specific fracturing process comprises the following steps shown in a table 6.
TABLE 5 fracturing fluid formulations
TABLE 6 Pumping procedure
After the fracturing construction process of the comparative example is adopted, the daily oil increment is 2.2t, and the stable yield time is 3 months.
Comparative example 2
In the octahedral river oil field, other fracturing processes are also tried in recent years, such as increasing sand adding strength, increasing liquid using strength and the like, but the problems are not solved fundamentally, analysis shows that the two or more fracturing modification scales are equivalent, the single well control reservoir failure is quicker, and the sand production problem still exists after partial well fracturing, so that the yield is reduced more quickly. For example, a M14-6-X27 well is fractured by a method for improving the sand adding strength and the sand ratio in 2017, a fracturing system shown in Table 7 is adopted, a concrete pumping program is shown in Table 8, and the total liquid entering the well is 161.9M3Sand addition amount of 30m3Average sand ratio of 28.6% and construction discharge capacity of 3.5m3Min, construction pressure 15MPa, and pump-stopping pressure 9 MPa. The whole construction condition is normal, and construction pressure is steady, accomplishes according to the design requirement and adds the sand. After fracturing, the oil yield per day is 3.9 tons at the initial stage, and the liquid yield per day is 12.7, so that a good oil increasing effect is obtained. But after one week of production the well had decreased production due to formation sand production.
TABLE 7 fracturing fluid formulations
TABLE 8 Pumping procedure
It is apparent that the above embodiments are only examples for clearly illustrating and do not limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications are therefore intended to be included within the scope of the invention as claimed.
Claims (10)
1. The fracturing process of the complicated long seam of the vertical well of the unconsolidated sandstone heavy oil reservoir is characterized by comprising the processes of once making high diversion long seam, temporarily plugging, twice steering making high diversion long seam and fracturing displacement fluid, and comprises the following specific steps:
1) making high-flow-guide long cracks at one time, injecting high-viscosity fracturing fluid into the unconsolidated strata to make cracks, and then injecting the fracturing fluid carrying small-particle-size proppant into the unconsolidated strata in batches according to the sequentially increasing low sand ratio; then, carrying out fractional injection on the fracturing fluid carrying the large-particle-size proppant according to sequentially increasing high sand ratios to finish primary fracturing;
2) temporary plugging process, namely reducing the discharge volume and injecting a temporary plugging agent into the joint after sand adding is finished;
3) turning for the second time to make a high-flow-guide long seam, lifting the discharge capacity to the condition in the step 1), repeating the seam making process in the step 1), and adding self-dispersing degradable fibers in a high sand ratio stage;
4) and (4) fracturing the displacement fluid, calculating the using amount of active water according to the lower deep volume of the oil well measure pipe column after the sand adding is finished, and replacing by adopting the active water.
2. The loose sandstone heavy oil reservoir straight-well complex long-fracture fracturing process of claim 1, wherein the low sand ratio is 10-40%, and the high sand ratio is 50-80%; the sand ratio increasing amplitude is 5-10%; when the sand ratio is 50-70%, the surface modified self-dispersed degradable fiber is added.
3. The loose sandstone heavy oil reservoir straight-well complex long-fracture fracturing process as claimed in claim 1, wherein the discharge capacity of the fracturing fluid in the step 1) and the step 3) is 4-5m3Min, the discharge amount of the temporary plugging agent in the step 2) is 1-2m3/min。
4. The loose sandstone heavy oil reservoir straight-well complex long-fracture fracturing process of claim 1, wherein the fracturing fluid comprises a base fluid and a crosslinking fluid, wherein the base fluid comprises the following components in percentage by mass: 0.35-0.5% of guanidine gum, 0.012-0.015% of NaOH0, 0.2-0.5% of cleanup additive, 1.0-2.0% of clay stabilizer, 0.3-0.5% of oil detergent, 0.01-0.02% of bactericide and the balance of water; the cross-linking liquid comprises the following components in percentage by mass: 0.8-1% of borax, 0.3-0.5% of gel breaker and the balance of water; the crosslinking ratio is 100 (4-5).
5. The unconsolidated sandstone heavy oil reservoir straight-well complex long-fracture fracturing process of claim 4, wherein the clay stabilizer is JC-NW 2; the oil washing agent is a nonionic surfactant.
6. The loose sandstone heavy oil reservoir straight-well complex long-crack fracturing process of claim 4, wherein the viscosity of the base fluid is 25-40 mPa-s, the viscosity of the gel after crosslinking is 150-200 mPa-s, and the viscosity of the gel breaker is 2-3.3 mPa-s.
7. The loose sandstone heavy oil reservoir straight-well complex long-fracture fracturing process of claim 1, wherein the small-particle size proppant has a size of 30-60 meshes, and the large-particle size proppant has a size of 20-40 meshes.
8. The loose sandstone heavy oil reservoir straight-well complex long-fracture fracturing process of claim 1, wherein the temporary plugging agent is a water-soluble alcohol polymer.
9. The loose sandstone heavy oil reservoir straight-well complex long-fracture fracturing process as claimed in claim 1, wherein in the temporary plugging process, the size of the temporary plugging agent is determined according to the previous fracturing fracture, the size of the temporary plugging agent is 4-120 meshes, and a large, medium and small particle size combination mode is adopted.
10. The vertical well complex long-fracture fracturing process for unconsolidated sandstone heavy oil reservoirs according to claim 1, wherein the self-dispersed degradable fibers are water-soluble alcohol polymers, and the dosage of the fibers relative to the fracturing fluid is 0.3-0.7 wt%.
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