CN111648741A - Chemical flooding method for medium-permeability reservoir - Google Patents
Chemical flooding method for medium-permeability reservoir Download PDFInfo
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- 239000000126 substance Substances 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims abstract description 35
- 229920000642 polymer Polymers 0.000 claims abstract description 65
- 239000006185 dispersion Substances 0.000 claims abstract description 53
- 239000002245 particle Substances 0.000 claims abstract description 53
- 238000006073 displacement reaction Methods 0.000 claims abstract description 50
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 46
- 239000007864 aqueous solution Substances 0.000 claims abstract description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 34
- 230000001681 protective effect Effects 0.000 claims abstract description 15
- 239000000243 solution Substances 0.000 claims abstract description 10
- 229920002401 polyacrylamide Polymers 0.000 claims description 42
- 230000035699 permeability Effects 0.000 claims description 18
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 3
- 229920001577 copolymer Polymers 0.000 claims description 3
- 229920001285 xanthan gum Polymers 0.000 claims description 3
- 229940082509 xanthan gum Drugs 0.000 claims description 3
- 235000010493 xanthan gum Nutrition 0.000 claims description 3
- 239000000230 xanthan gum Substances 0.000 claims description 3
- 239000003921 oil Substances 0.000 abstract description 69
- 238000011084 recovery Methods 0.000 abstract description 18
- 239000010779 crude oil Substances 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 4
- 239000010865 sewage Substances 0.000 description 22
- 239000011435 rock Substances 0.000 description 21
- 230000000052 comparative effect Effects 0.000 description 8
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000005465 channeling Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229920000620 organic polymer Polymers 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 241000237858 Gastropoda Species 0.000 description 1
- 230000033558 biomineral tissue development Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000004005 microsphere Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
Classifications
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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
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
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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
- C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
- C09K8/588—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids characterised by the use of specific polymers
-
- 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
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
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Abstract
The invention relates to a chemical flooding method for a medium-permeability reservoir, belonging to the technical field of petrochemical flooding. The chemical flooding method comprises the following steps: 1) injecting a first heterogeneous disperse system into a reservoir to form a front slug; 2) then injecting polymer aqueous solution into the reservoir to form a main slug or alternatively injecting the polymer aqueous solution into the reservoir and respectively forming a main slug and a profile control slug by a profile control system; 3) injecting a second heterogeneous disperse system into the reservoir to form a protective slug; the first heterogeneous dispersion system mainly comprises a first polymer, a viscoelastic particle oil displacement agent and water; the aqueous polymer solution consists essentially of a second polymer and water; the second heterogeneous dispersion system is mainly composed of a third polymer, a viscoelastic particle oil displacement agent and water. The chemical flooding method can improve the core plugging rate of the medium-permeability reservoir, effectively start the residual oil in the strong water flooded area and the medium-permeability core, and achieve the effect of greatly improving the crude oil recovery ratio.
Description
Technical Field
The invention relates to a chemical flooding method for a medium-permeability reservoir, belonging to the technical field of petrochemical flooding.
Background
At present, the demand of China on petroleum energy is continuously increased, but the I and II-type scale reserves of most onshore oil fields in China are used up, the oil fields enter the later development stage, and the reserves of the residual medium-permeability oil reservoirs become the main position for maintaining the yield of the oil fields.
The permeability of the medium-permeability oil reservoir has a wide variation range, and is generally 50-1000 × 10-3μm2. The residual oil in the medium-permeability reservoir is distributed in a strong water-flooded area, accounting for 50-60% of the residual oil reserve, and a considerable proportion of the residual oil is mainly distributed in an oil layer below the average permeability, which is the key point of chemical flooding. In order to displace the residual oil in the oil reservoir, the mobility ratio must be effectively improved, the high-permeability layer is blocked, the low-permeability layer is started by the fluid, and the purposes of expanding swept volume and greatly improving the oil displacement efficiency are achieved. However, in the actual chemical flooding application process, the chemical oil displacement agent is easy to flow by, has a certain action period, cannot effectively displace residual oil in the medium-low permeability rock core, and achieves the purpose of improving the crude oil recovery rate. Thus how to effectively displace the medium permeability reservoirThe residual oil and the residual reserve are used, and the improvement of the crude oil recovery rate becomes the problem to be solved urgently at present.
Disclosure of Invention
The invention aims to provide a chemical flooding method for a medium-permeability reservoir, which can effectively improve the crude oil recovery ratio of the medium-permeability reservoir.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a chemical flooding method for a medium-permeability reservoir comprises the following steps:
1) injecting a first heterogeneous disperse system into a reservoir to form a front slug;
2) then carrying out step A) or step B);
step A) injecting a polymer aqueous solution into the reservoir to form a main body slug;
step B) alternately injecting a polymer aqueous solution and a profile control system into the reservoir to respectively form a main slug and a profile control slug;
3) injecting a second heterogeneous disperse system into the reservoir to form a protective slug;
the first heterogeneous dispersion system mainly comprises a first polymer, a viscoelastic particle oil displacement agent and water; in the heterogeneous dispersion system, the mass fraction of the first polymer is 0.08-0.15%, and the mass fraction of the viscoelastic particle oil displacement agent is 0.02-0.08%;
the aqueous polymer solution consists essentially of a second polymer and water; the mass fraction of the second polymer in the polymer aqueous solution is 0.1-0.15%;
the second heterogeneous dispersion system mainly comprises a third polymer, a viscoelastic particle oil displacement agent and water; in the second heterogeneous dispersion system, the mass fraction of the third polymer is 0.08-0.15%, and the mass fraction of the viscoelastic particle oil displacement agent is 0.02-0.08%.
According to the chemical flooding method for the medium-permeability reservoir, the adopted heterogeneous dispersion system has strong viscoelasticity, the suspension property of a viscoelastic particle profile control agent can be improved, the injection property of a viscoelastic particle oil displacement agent is improved, and the viscoelastic particle profile control agent is easier to inject into a core, so that the heterogeneous dispersion system is injected into the reservoir in a front slug stage and a protective slug stage, the core plugging rate of the medium-permeability reservoir can be improved, the residual oil in a strong water flooding area and a medium-permeability core is effectively started, and the effect of greatly improving the crude oil recovery rate is achieved; meanwhile, the heterogeneous dispersion system can improve the heterogeneity, enlarge the swept volume and improve the crude oil recovery ratio of the middle-permeability core.
The chemical flooding method of the medium-permeability reservoir combines a heterogeneous dispersion system and a polymer flooding system for multiple times of profile control and flooding, thereby achieving the purpose of greatly improving the crude oil recovery ratio. The viscoelastic particle oil displacement agent in the adopted heterogeneous dispersion system has viscosity and elasticity, and the formed front-mounted slug can effectively block a large pore channel, adjust the water absorption profile of a reservoir, establish seepage resistance, prevent polymer channeling and enlarge swept volume; the main slug formed by the polymer water solution has the advantages of improving the fluidity control function and the oil displacement effect; the protective slug formed by the heterogeneous dispersion system can effectively inhibit rapid fingering in the subsequent water flooding process, and improve the validity period of chemical flooding and the effective utilization rate of the polymer. In addition, the front-end slug and the protective slug formed by the heterogeneous disperse system can effectively block the channeling channel without influencing the subsequent steps.
Preferably, the first heterogeneous dispersion system is obtained by uniformly mixing the first polymer, the viscoelastic particle oil displacement agent and the oilfield sewage. The polymer aqueous solution is obtained by uniformly mixing a second polymer and the oilfield sewage. The second heterogeneous dispersion system is obtained by uniformly mixing a third polymer, a viscoelastic particle oil displacement agent and oil field sewage. Further, the sulfur content of the oilfield sewage is 0, and the oxygen content is lower than 0.1 mg/L.
Preferably, the first polymer and the second polymer are independently selected from one or any combination of polyacrylamide, a copolymer of acrylamide and acrylic acid, xanthan gum. Among the organic matters, the solution formed by dissolving polyacrylamide in water has higher viscosity, which not only effectively improves the suspension property of the viscoelastic particle oil displacement agent (the density of the viscoelastic particle oil displacement agent is greater than the density of water and is easy to deposit in water), but also enables the viscoelastic particle oil displacement agent to be uniformly dispersed in the water phase, thereby improving the injection property and the migration property of a heterogeneous dispersion system. Several of the polymers listed above can improve the plugging properties of heterogeneous dispersions by increasing the viscoelasticity of the heterogeneous dispersion.
Preferably, the first polymer, the second polymer and the third polymer are independently selected from polyacrylamide with the number average molecular weight of 1500-2200 ten thousand. The polyacrylamide with the number average molecular weight can enable the heterogeneous solution to have higher viscosity and viscoelasticity, can effectively adjust the stratum, improves the heterogeneity, and can ensure that the viscoelastic particle oil displacement agent is smoothly injected without blocking the stratum. And the polyacrylamide aqueous solution with the number average molecular weight has higher viscosity and viscoelasticity, so that the swept volume and the oil displacement efficiency of the polymer can be effectively improved when a main slug is formed.
The injectivity of the viscoelastic particle oil displacement agent is influenced by the permeability of a reservoir, the permeability is too high, the viscoelastic particle oil displacement agent is enabled to rapidly break through the reservoir, the effects of improving a water absorption profile and expanding swept volume cannot be achieved, the permeability is too low, the viscoelastic particle oil displacement agent cannot be smoothly injected into the reservoir, and the reservoir is preferably (50-400) × 10-3μm2For example, the permeability of the reservoir may be 100 to 400 × 10-3μm2And may be 50 to 300 × 10-3μm2. The permeability of the invention refers to gas permeability.
Preferably, in the step 1), the volume of the front slug is 0.05-0.1 PV; step 2) when the step A) is carried out, the volume of the main body slug is 0.35-0.6 PV; step 2) when the step B) is carried out, the total volume of the main body slug is 0.35-0.6 PV; in the step 3), the volume of the protective slug is 0.05-0.1 PV.
The polymer aqueous solution and the profile control system are alternately injected, so that the cross flow of the polymer aqueous solution can be prevented or stopped, the swept volume of the polymer is further enlarged, and the effective utilization rate of the polymer is improved. In the step B), when the polymer aqueous solution and the profile control system are alternately injected, the polymer aqueous solution is injected firstly and then is alternated, and the alternation frequency is an even number which is more than or equal to 2. Furthermore, the alternating times are more than or equal to 4 times. For example, in step B), the number of alternations is 2, and the body slug consists of a first body slug and a second body slug, and the profile control slug is located between the first body slug and the second body slug. The first body slug is formed from the aqueous polymer solution injected before the first alternation and the second body slug is formed from the aqueous polymer solution injected after the second alternation. Of course, the number of the alternation may also be 4, and in the step B), the main body slug includes a first main body slug, a second main body slug and a third main body slug, the profile control slug includes a first profile control slug and a second profile control slug, and the first main body slug, the first profile control slug, the second main body slug, the second profile control slug and the third main body slug are sequentially arranged.
Preferably, the volume of the first main body section plug is 0.2-0.4 PV, and the volume of the second main body section plug is 0.15-0.2 PV.
Preferably, the split system is a third heterogeneous dispersion system; the third heterogeneous dispersion system mainly comprises a fourth polymer, a particle oil displacement agent and water; in the third heterogeneous dispersion system, the mass fraction of the fourth polymer is 0.08-0.15%, and the mass fraction of the particle oil-displacing agent is 0.02-0.08%. The profile control slug adopts a heterogeneous disperse system, can effectively move in the stratum, and can deform under the external pressure, thereby realizing the plugging of a large pore passage. Furthermore, in the third heterogeneous dispersion system, the mass fraction of the fourth polymer is 0.1-0.15%, and the mass fraction of the viscoelastic particle oil displacement agent is 0.04-0.08%. Further, the particulate oil-displacing agent in the third heterogeneous dispersion system is preferably organic polymer-based flexible particles. The organic polymer flexible particles are at least one of viscoelastic particle oil displacement agents, polymer microspheres and bulked particles. Further, the third heterogeneous dispersion system is mainly obtained by uniformly mixing a fourth polymer, a particle oil displacement agent and oil field sewage.
In order to further enlarge swept volume and improve reservoir flooding efficiency, preferably, the fourth polymer is selected from one or any combination of polyacrylamide, a copolymer of acrylamide and acrylic acid, and xanthan gum.
Preferably, the fourth polymer is polyacrylamide having a number average molecular weight of 1500 to 2200 ten thousand.
Preferably, in the step B), the total volume of the profile control slug is 0.01-0.05 PV. The profile control slug with the total volume can be injected to enable a profile control system to be pushed to a well distance of 1/3-1/2, a polymer water solution cross flow channel is blocked, and the swept volume is further enlarged.
Preferably, the average particle size of the particles of the viscoelastic particle oil displacement agent is 50-150 μm. Furthermore, the viscoelastic particle oil displacement agent forms a dispersion system with the concentration of 5000mg/L in aged sewage (TDS4500mg/L), the viscosity is more than or equal to 150mPa & s, and the elastic modulus is more than or equal to 0.75Pa at the temperature of 30 ℃. The viscoelastic particle oil displacement agent forms a dispersion with the concentration of 5000mg/L in aged sewage (TDS4500mg/L), and the particle size is more than or equal to 300 mu m after the dispersion swells for 4-6 h at 65 ℃.
Preferably, the chemical flooding method further comprises the steps of: and after a protective slug is formed, performing water flooding on the reservoir.
Detailed Description
The present invention will be further described with reference to the following embodiments.
The reservoirs in the chemical flooding methods of the medium permeability reservoirs of examples 1-5 and comparative examples are artificial cores with triple permeability differences of phi 2.5cm × 10cm (300 × 10 cm)-3μm2/900×10-3μm2) The porosity of the artificial double-tube parallel heterogeneous cylindrical core is 24%. Before chemical flooding, the cores were treated as follows: the core was saturated with crude oil at 65 ℃ (the crude oil from a certain oil field oil sump after dehydration and degassing treatment was 12.8mPa · s) with the original oil saturation (Soi) controlled to be about 70%. Before starting the chemical flooding of examples 1-5 and comparative example, filtered aged sewage (same as the aged sewage used in example 1) is injected into the artificial core of saturated crude oil at a speed of 50mL/h to displace oil, and the water flooding is finished until no oil is produced, and the water flooding recovery ratio is obtained through calculation, and the results are shown in Table 1.
The polyacrylamide aqueous solution adopted in the chemical flooding method for the medium-permeability reservoir in the embodiment 1-5 is obtained by uniformly mixing polyacrylamide and aged sewage, and the heterogeneous dispersion system is obtained by uniformly mixing the viscoelastic particle oil displacement agent, the polyacrylamide and the aged sewage.
The polyacrylamide used for preparing the polyacrylamide aqueous solution and the heterogeneous dispersion system in each example is polyacrylamide with the number average molecular weight of 2200 ten thousand, the hydrolysis degree of the polyacrylamide is 25.63 percent, the total dissolved solid content (TDS) in clear water is 362.4mg/L, and the viscosity of the polyacrylamide aqueous solution (taking the clear water as a solvent) with the mass concentration of 1000mg/L is 58.7 mPas;
in each example, the aged sewage used for preparing the polyacrylamide aqueous solution and the heterogeneous dispersion system and the injected aged sewage are the aged sewage (with 0 sulfur content and less than 0.1mg/L oxygen content) of certain oil field subjected to sulfur removal, the total mineralization is 4312.47mg/L, and Ca is added2+、Mg2+The total content of (b) was 39.93 mg/L.
The viscoelastic particle oil displacement agent (PPG) adopted by the heterogeneous dispersion system in each example has an average particle size of 352 mu m; the viscoelastic particle oil displacement agent forms a dispersion system with the concentration of 5000mg/L in aged sewage (TDS4500mg/L), the viscosity is more than or equal to 150mPa & s, and the elastic modulus is more than or equal to 0.75Pa under the condition of 30 ℃; and the viscoelastic particle oil displacement agent forms a dispersion with the concentration of 5000mg/L in aged sewage (TDS4500mg/L), and the particle size is more than or equal to 300 mu m after the dispersion is swelled at 65 ℃ for 5 h.
Example 1
The chemical flooding method of the medium permeability reservoir in the embodiment specifically comprises the following steps:
1) injecting a heterogeneous dispersion system into the artificial rock core at a flow rate of 50mL/h to form a 0.05PV front slug;
2) then injecting a polyacrylamide aqueous solution into the artificial rock core to form a 0.55PV main body slug;
3) then injecting a heterogeneous disperse system into the artificial rock core to form a 0.1PV protective slug;
4) and finally, injecting aged sewage into the artificial rock core at the flow rate of 50mL/h for oil displacement, and finishing the subsequent water displacement until no oil is produced.
In the heterogeneous dispersion system in steps 1) and 3) of this example, the mass fraction of polyacrylamide is 0.12%, and the mass fraction of the viscoelastic particle oil-displacing agent is 0.08%; the mass fraction of the polyacrylamide aqueous solution adopted in the step 2) is 0.15%.
Example 2
The chemical flooding method of the medium permeability reservoir comprises the following steps:
1) injecting a heterogeneous dispersion system into the artificial rock core at a flow rate of 50mL/h to form a 0.05PV front slug;
2) then sequentially injecting polyacrylamide aqueous solution into the artificial rock core to form a first main body slug of 0.25PV, injecting a heterogeneous disperse system to form a profile control slug of 0.05PV, and injecting polyacrylamide aqueous solution to form a second main body slug of 0.3 PV;
3) then injecting a heterogeneous disperse system into the artificial rock core to form a 0.05PV protective slug;
4) and finally, injecting aged sewage into the artificial rock core at the flow rate of 50mL/h for oil displacement, and finishing the subsequent water displacement until no oil is produced.
In the heterogeneous dispersion system in steps 1), 2) and 3) of this example, the mass fraction of polyacrylamide is 0.12%, and the mass fraction of the viscoelastic particle oil-displacing agent is 0.08%; the mass fraction of the polyacrylamide aqueous solution adopted in the step 2) is 0.15%.
Example 3
The chemical flooding method of the medium permeability reservoir comprises the following steps:
1) injecting a heterogeneous dispersion system into the artificial rock core at a flow rate of 50mL/h to form a 0.05PV front slug;
2) then sequentially injecting polyacrylamide aqueous solution into the artificial core to form a first main body slug with 0.2PV, injecting a heterogeneous dispersion system to form a first profile control slug with 0.025PV, injecting polyacrylamide aqueous solution to form a second main body slug with 0.2PV, injecting a heterogeneous dispersion system to form a second profile control slug with 0.025PV and injecting polyacrylamide aqueous solution to form a third main body slug with 0.15 PV;
3) then injecting a heterogeneous disperse system into the artificial rock core to form a 0.05PV protective slug;
4) and finally, injecting aged sewage into the artificial rock core at the flow rate of 50mL/h for oil displacement, and finishing the subsequent water displacement until no oil is produced.
In the heterogeneous dispersion system in steps 1), 2) and 3) of this example, the mass fraction of polyacrylamide is 0.12%, and the mass fraction of the viscoelastic particle oil-displacing agent is 0.08%; the mass fraction of the polyacrylamide aqueous solution adopted in the step 2) is 0.15%.
Example 4
The chemical flooding method of the medium permeability reservoir comprises the following steps:
1) firstly injecting a heterogeneous dispersion system into the artificial rock core at the flow rate of 50mL/h to form a front slug of 0.075 PV;
2) then sequentially injecting polyacrylamide aqueous solution into the artificial rock core to form a first main body slug of 0.2PV, injecting a heterogeneous disperse system to form a first profile control slug of 0.025PV, injecting polyacrylamide aqueous solution to form a second main body slug of 0.2PV, injecting a heterogeneous disperse system to form a second profile control slug of 0.025PV and injecting polyacrylamide aqueous solution to form a third main body slug of 0.1 PV;
3) then injecting a heterogeneous disperse system into the artificial rock core to form a 0.075PV protective slug;
4) and finally, injecting aged sewage into the artificial rock core at the flow rate of 50mL/h for oil displacement, and finishing the subsequent water displacement until no oil is produced.
In the heterogeneous dispersion system in steps 1), 2) and 3) of this example, the mass fraction of polyacrylamide is 0.12%, and the mass fraction of the viscoelastic particle oil-displacing agent is 0.08%; the mass fraction of the polyacrylamide aqueous solution adopted in the step 2) is 0.15%.
Example 5
The chemical flooding method of the medium permeability reservoir comprises the following steps:
1) injecting a heterogeneous disperse system into the artificial rock core at a flow rate of 50mL/h to form a 0.1PV front slug;
2) then sequentially injecting a polyacrylamide aqueous solution into the artificial core to form a first main body slug with 0.15PV, injecting a heterogeneous dispersion system to form a first profile control slug with 0.025PV, injecting a polyacrylamide aqueous solution to form a second main body slug with 0.15PV, injecting a heterogeneous dispersion system to form a second profile control slug with 0.025PV and injecting a polyacrylamide aqueous solution to form a third main body slug with 0.15 PV;
3) then injecting a heterogeneous disperse system into the artificial rock core to form a 0.1PV protective slug;
4) and finally, injecting aged sewage into the artificial rock core at the flow rate of 50mL/h for oil displacement, and finishing the subsequent water displacement until no oil is produced.
In the heterogeneous dispersion system in steps 1), 2) and 3) of this example, the mass fraction of polyacrylamide is 0.12%, and the mass fraction of the viscoelastic particle oil-displacing agent is 0.08%; the mass fraction of the polyacrylamide aqueous solution adopted in the step 2) is 0.15%.
Comparative example 1
The chemical flooding method of the medium-permeability reservoir of the comparative example comprises the following steps:
1) injecting a polyacrylamide aqueous solution with the fraction of 0.15% into the rock core at the flow rate of 50mL/h to form a main body slug with the pressure of 0.7 PV;
2) and then injecting aged sewage into the artificial rock core at the flow rate of 50mL/h to drive oil, and finishing the subsequent water drive until oil does not exist any more.
The aqueous polyacrylamide solution used in this comparative example was completely the same as that used in example 1.
Test examples
The specific recovery ratios of the chemical flooding methods of experimental examples 1 to 5 and comparative example 1 were calculated, and the calculation results are shown in table 1.
Oil-penetrated reservoir recovery data in Table 1
| Method of producing a composite material | Water flooding recovery/％ | Chemical flooding recovery/percent | Enhanced recovery amplitude/degree |
| Example 1 | 31.12 | 56.31 | 25.19 |
| Example 2 | 31.15 | 58.38 | 27.23 |
| Example 3 | 30.39 | 61.67 | 31.28 |
| Example 4 | 30.62 | 62.37 | 31.75 |
| Example 5 | 30.53 | 62.85 | 32.32 |
| Comparative example 1 | 30.86 | 55.64 | 24.78 |
As can be seen from Table 1, compared with examples 1-5, the recovery ratio improvement amplitude of comparative example 1 is relatively low, so that the preposed slug and the protective slug play a good role in protecting the polymer flooding, and the sweep volume is favorably expanded. Thereby greatly improving the recovery ratio. In comparison with examples 1 to 5, example 5 showed the highest enhanced recovery ratio, example 2 showed the second enhanced recovery ratio, and example 1 showed the lowest enhanced recovery ratio. The more the alternation times of the slugs are, the longer the effective period of the chemical oil displacement system is, and the chemical oil displacement agent can have effective action in the whole process of the core.
Claims (10)
1. A chemical flooding method for a medium-permeability reservoir is characterized by comprising the following steps: the method comprises the following steps:
1) injecting a first heterogeneous disperse system into a reservoir to form a front slug;
2) then carrying out step A) or step B);
step A) injecting a polymer aqueous solution into the reservoir to form a main body slug;
step B) alternately injecting a polymer aqueous solution and a profile control system into the reservoir to respectively form a main slug and a profile control slug;
3) injecting a second heterogeneous disperse system into the reservoir to form a protective slug;
the first heterogeneous dispersion system mainly comprises a first polymer, a viscoelastic particle oil displacement agent and water; in the heterogeneous dispersion system, the mass fraction of the first polymer is 0.08-0.15%, and the mass fraction of the viscoelastic particle oil displacement agent is 0.02-0.08%;
the aqueous polymer solution consists essentially of a second polymer and water; the mass fraction of the second polymer in the polymer aqueous solution is 0.1-0.15%;
the second heterogeneous dispersion system mainly comprises a third polymer, a viscoelastic particle oil displacement agent and water; in the second heterogeneous dispersion system, the mass fraction of the third polymer is 0.08-0.15%, and the mass fraction of the viscoelastic particle oil displacement agent is 0.02-0.08%.
2. The chemical flooding method of a medium-permeability reservoir of claim 1, characterized in that: the first polymer and the second polymer are independently selected from one or any combination of polyacrylamide, a copolymer of acrylamide and acrylic acid and xanthan gum.
3. The chemical flooding method of a medium-permeability reservoir of claim 2, characterized in that: the first polymer, the second polymer and the third polymer are independently selected from polyacrylamide with the number average molecular weight of 1500-2200 ten thousand.
4. The chemical flooding method of the medium-permeability reservoir of claim 1, characterized in that the permeability of the reservoir is (50-400) × 10-3μm2。
5. The chemical flooding method of a medium-permeability reservoir of claim 1, characterized in that:
in the step 1), the volume of the front slug is 0.05-0.1 PV;
step 2) when the step A) is carried out, the volume of the main body slug is 0.35-0.6 PV; step 2) when the step B) is carried out, the total volume of the main body slug is 0.35-0.6 PV;
in the step 3), the volume of the protective slug is 0.05-0.1 PV.
6. The chemical flooding method of a medium-permeability reservoir according to any one of claims 1 to 5, characterized by comprising: in step B), the number of alternation is 2, the main body slug consists of a first main body slug and a second main body slug, and the profile control slug is positioned between the first main body slug and the second main body slug.
7. The chemical flooding method of a medium-permeability reservoir of claim 6, characterized in that: the volume of the first main body slug is 0.2-0.4 PV, and the volume of the second main body slug is 0.15-0.2 PV.
8. The chemical flooding method of a medium-permeability reservoir according to any one of claims 1 to 5, characterized by comprising: the splitting system is a third heterogeneous dispersion system; the third heterogeneous dispersion system mainly comprises a fourth polymer, a particle oil displacement agent and water; in the third heterogeneous dispersion system, the mass fraction of the fourth polymer is 0.08-0.15%, and the mass fraction of the particle oil-displacing agent is 0.02-0.08%.
9. The chemical flooding method of a medium-permeability reservoir of claim 1, characterized in that: in the step B), the total volume of the profile control slug is 0.01-0.05 PV.
10. The chemical flooding method of a medium-permeability reservoir according to any one of claims 1 to 5, characterized by comprising: the average particle size of the particles of the viscoelastic particle oil displacement agent is 50-150 mu m.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112343567A (en) * | 2020-10-20 | 2021-02-09 | 中国石油化工股份有限公司 | Chemical flooding injection method based on high-water-content oil reservoir with large water channel |
| CN114810015A (en) * | 2022-04-15 | 2022-07-29 | 中国石油化工股份有限公司 | Method for improving recovery ratio of oil reservoir after chemical flooding |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU6819398A (en) * | 1998-04-06 | 1999-10-25 | Da Qing Petroleum Administration Bureau | A foam drive method |
| CN102242625A (en) * | 2011-04-25 | 2011-11-16 | 中国石油化工股份有限公司 | Method for improving recovery ratio of crude oil of oil deposit after polymer flooding |
| CN106285589A (en) * | 2016-08-16 | 2017-01-04 | 中国石油化工股份有限公司 | A kind of method improving ternary composite driving recovery ratio |
| CN109385257A (en) * | 2017-08-06 | 2019-02-26 | 大庆东油睿佳石油科技有限公司 | A kind of double slug Compositional type profile control agents of low-permeability sandstone oil reservoir and its application method |
| CN110529085A (en) * | 2019-08-21 | 2019-12-03 | 中国石油化工股份有限公司 | A kind of chemical flooding method of heavy crude reservoir |
| CN110544514A (en) * | 2019-08-29 | 2019-12-06 | 中国石油化工股份有限公司 | Proportioning optimization method of heterogeneous chemical oil displacement system |
-
2020
- 2020-06-02 CN CN202010491408.9A patent/CN111648741A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU6819398A (en) * | 1998-04-06 | 1999-10-25 | Da Qing Petroleum Administration Bureau | A foam drive method |
| CN102242625A (en) * | 2011-04-25 | 2011-11-16 | 中国石油化工股份有限公司 | Method for improving recovery ratio of crude oil of oil deposit after polymer flooding |
| CN106285589A (en) * | 2016-08-16 | 2017-01-04 | 中国石油化工股份有限公司 | A kind of method improving ternary composite driving recovery ratio |
| CN109385257A (en) * | 2017-08-06 | 2019-02-26 | 大庆东油睿佳石油科技有限公司 | A kind of double slug Compositional type profile control agents of low-permeability sandstone oil reservoir and its application method |
| CN110529085A (en) * | 2019-08-21 | 2019-12-03 | 中国石油化工股份有限公司 | A kind of chemical flooding method of heavy crude reservoir |
| CN110544514A (en) * | 2019-08-29 | 2019-12-06 | 中国石油化工股份有限公司 | Proportioning optimization method of heterogeneous chemical oil displacement system |
Non-Patent Citations (1)
| Title |
|---|
| 张莉等: "聚合物驱后油藏提高采收率技术研究", 《石油与天然气化工》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112343567A (en) * | 2020-10-20 | 2021-02-09 | 中国石油化工股份有限公司 | Chemical flooding injection method based on high-water-content oil reservoir with large water channel |
| CN114810015A (en) * | 2022-04-15 | 2022-07-29 | 中国石油化工股份有限公司 | Method for improving recovery ratio of oil reservoir after chemical flooding |
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