CN110643337A - Degradation agent for removing polymer blockage of sand control well near wellbore zone of screen pipe in polymer injection zone and preparation method and application thereof - Google Patents
Degradation agent for removing polymer blockage of sand control well near wellbore zone of screen pipe in polymer injection zone and preparation method and application thereof Download PDFInfo
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- 239000004576 sand Substances 0.000 title claims abstract description 70
- 229920000642 polymer Polymers 0.000 title claims abstract description 63
- 239000003795 chemical substances by application Substances 0.000 title claims abstract description 58
- 230000015556 catabolic process Effects 0.000 title claims abstract description 48
- 238000006731 degradation reaction Methods 0.000 title claims abstract description 48
- 238000002347 injection Methods 0.000 title claims abstract description 37
- 239000007924 injection Substances 0.000 title claims abstract description 37
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 35
- 238000010276 construction Methods 0.000 claims abstract description 29
- 230000000593 degrading effect Effects 0.000 claims abstract description 23
- 230000000694 effects Effects 0.000 claims abstract description 16
- 230000002579 anti-swelling effect Effects 0.000 claims abstract description 12
- 239000003999 initiator Substances 0.000 claims abstract description 10
- 238000004140 cleaning Methods 0.000 claims abstract description 9
- 239000004094 surface-active agent Substances 0.000 claims abstract description 9
- 239000003381 stabilizer Substances 0.000 claims abstract description 7
- 238000001125 extrusion Methods 0.000 claims abstract description 6
- 239000000203 mixture Substances 0.000 claims abstract description 3
- 239000003921 oil Substances 0.000 claims description 48
- 239000007788 liquid Substances 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 23
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 21
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical group [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims description 18
- 239000012530 fluid Substances 0.000 claims description 18
- 238000005086 pumping Methods 0.000 claims description 17
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical group Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 12
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 12
- 239000010779 crude oil Substances 0.000 claims description 12
- 230000009467 reduction Effects 0.000 claims description 11
- 238000003860 storage Methods 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 9
- 239000001103 potassium chloride Substances 0.000 claims description 9
- 235000011164 potassium chloride Nutrition 0.000 claims description 9
- POAOYUHQDCAZBD-UHFFFAOYSA-N 2-butoxyethanol Chemical compound CCCCOCCO POAOYUHQDCAZBD-UHFFFAOYSA-N 0.000 claims description 7
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 6
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 claims description 6
- 230000015572 biosynthetic process Effects 0.000 claims description 5
- 239000000047 product Substances 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 238000004090 dissolution Methods 0.000 claims description 4
- 238000002955 isolation Methods 0.000 claims description 4
- 239000006185 dispersion Substances 0.000 claims description 3
- 239000003814 drug Substances 0.000 claims description 3
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- 238000012360 testing method Methods 0.000 claims description 3
- 239000000654 additive Substances 0.000 claims description 2
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- 239000008380 degradant Substances 0.000 claims description 2
- 238000000605 extraction Methods 0.000 abstract description 2
- 239000003129 oil well Substances 0.000 description 11
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- 208000027418 Wounds and injury Diseases 0.000 description 2
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- 238000005516 engineering process Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
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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
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
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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
- C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
- C09K8/524—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning organic depositions, e.g. paraffins or asphaltenes
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Abstract
The invention belongs to the technical field of oil extraction in oil fields, and particularly relates to a degrading agent for removing polymer blockage of a sand control well near-wellbore zone of a screen pipe in a polymer injection zone, and a preparation method and application thereof. The degrading agent comprises a degrading agent I: 90-100 parts of clean water, 0.71-1.16 parts of surfactant composition with cleaning effect, 0.12-0.26 part of stabilizer and 1-2 parts of anti-swelling agent; and (3) a degrading agent II: 90-100 parts of clear water, 1-1.5 parts of anti-swelling agent, 0.05-0.08 part of pH value regulator and 0.12-3.12 parts of initiator. The application provides a degradation agent for removing the blockage of a sand well near-well zone of a screen pipe in an injection zone of a loose sandstone reservoir by adopting a reverse extrusion construction method, and a slotted screen pipe (or a wire-wrapped screen pipe and the like) is adopted for removing the blockage problem of a polymer in a sand well near-well zone of a sand well which is benefited by the injection zone and is produced by a sand well.
Description
Technical Field
The invention belongs to the technical field of oil extraction in oil fields, and particularly relates to a degrading agent for removing polymer blockage of a sand control well near-wellbore zone of a screen pipe in a polymer injection zone, and a preparation method and application thereof.
Background
With the continuous deepening of secondary development and tertiary oil recovery, the injection-polymerization scale is continuously increased, a polyacrylamide oil displacement technology is mainly adopted on site, and basically, Polyacrylamide (PAM) or partially Hydrolyzed Polyacrylamide (HPAM) is used. Meanwhile, the contradiction between polymer injection and sand production is increasingly prominent, and the strong sand carrying capacity of the polymer aggravates the formation sand production, so that the oil well can normally produce after plugging removal and sand control, and whether the success of sand control of the oil well in a polymer injection area is benefited or not is directly related to the development effect of the polymer injection area.
At present, the sand control process of an oil well in a polymer injection region mainly adopts mechanical sand control, and accounts for more than 85% of the total sand control workload each year. The sand prevention method belongs to the category of fracturing filling, can reform the stratum, has the effect of increasing the yield and can meet the construction requirements of different well conditions. The working principle is that after the stratum is pretreated, the stratum is extruded and filled with sand with large sand amount and high sand ratio, and a slotted pipe (or a wire-wound sieve pipe) is adopted in a shaft to block the sand, so that a plurality of defense lines are formed and sand production is prevented; the method has the characteristics of large treatment radius, high filling efficiency, dense sand filling, capability of recovering stratum stress stable stratum, capability of decomposing near-wellbore zone liquid flow and relieving positive impact of liquid flow on blastholes and the like. The sand control method has certain construction scale on the conventional sand producing oil well, but has the following problems in the sand production treatment of the oil well in the polymer injection area.
Firstly, most oil reservoirs in the polymer injection region belong to loose sandstone oil reservoirs easy to produce sand, and after a polymer with certain viscosity is injected into an oil well, the viscosity of produced liquid is increased, the sand carrying capacity is strong, so that the formation sand production is aggravated, and the effective sand control period of the oil well is shortened. The average effective period of sand control of the oil well after the polymer injection is shortened by 62 days compared with that before the polymer injection.
Secondly, compare with conventional water drive, the stratum sand that polymer solution carried is more than conventional water drive, make can be along with the unable well bore that discharges of the fine silt sand in the stratum of output fluid discharge under conventional water drive condition, result in the fine silt sand in the stratum to get into in the gap between the sand control filling layer, thereby make macromolecule polyacrylamide pass through chemical adsorption, mechanical entrapment is detained in the narrow and small gap in the sand control layer, cause the sand control layer area of overflowing to reduce, the liquid flow resistance greatly increased, aggravate the jam of sand control filter layer, the reservoir permeability reduces, cause partial oil well liquid production volume to descend by a wide margin, the exploitation effect in notes gathering the district has been influenced. And (4) counting 43 well times of sand control of the polymer injection beneficiary well in 2013-2015 year, wherein the liquid amount is reduced by 7 well times, which accounts for 16% of the sand control workload of the polymer injection beneficiary well. As for West XX wells: the lower part of the well sand control target layer is provided with a weak water flooded layer with the same layer, so that the construction scale is limited in order to avoid high water content, and the gravel packing sand control operation is extruded in 12 months in 2014. The well is protected against the previous daily production liquid of 18.77m3 and the daily oil production of 3.41t, and is protected against the later initial daily production liquid of 9.65m3 and the daily oil production of 3.42t, the daily production liquid of 3.7m3 and the daily oil production of 1.9t are reduced after 47 days, and the laminated production is supplemented in 4 months in 2015.
Therefore, the polymer blockage of the sand control well near the well zone of the screen pipe in the polymer injection zone of the unconsolidated sandstone reservoir can be relieved, so that the comprehensive effect of polymer injection exploitation is improved.
Disclosure of Invention
The invention aims to provide a degrading agent for removing polymer blockage of a sand control well near wellbore zone of a screen pipe in a polymer injection zone, and a preparation method and application thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
a degradation agent for removing polymer blockage of a sand control well near wellbore zone of a screen pipe in a polymer injection zone comprises the following components in parts by mass:
degrading agent I: 90-100 parts of clean water, 0.71-1.16 parts of surfactant composition with cleaning effect, 0.12-0.26 part of stabilizer and 1-2 parts of anti-swelling agent;
and (3) a degrading agent II: 90-100 parts of clear water, 1-1.5 parts of anti-swelling agent, 0.05-0.08 part of pH value regulator and 0.12-3.12 parts of initiator.
The surfactant combination comprises the following components: 0.45-0.63 part of mixed benzene, 0.42-0.42 part of OP-100.21 and 0.05-0.11 part of ethylene glycol monobutyl ether.
The stabilizer is alkylolamide; the anti-swelling agent is potassium chloride; the PH value regulator is hydrochloric acid; the initiator is 0.12-0.25 part of ammonium persulfate and/or 1.06-3.12 parts of ferrous sulfate heptahydrate.
The application also comprises a preparation method of the degradation agent for removing the polymer blockage of the near wellbore zone of the sand control well of the screen pipe in the polymer injection zone, which comprises the following steps:
1) preparation of a degradation agent I: firstly, before preparation, a liquid storage tank is connected with a pump truck through a pipeline, a circulating system is established, clear water in the liquid storage tank is fully circulated, a surfactant combination is slowly added into a charging hopper of the pump truck, and a stabilizer is added after uniform stirring for full circulation; simultaneously adding an anti-swelling agent, and circulating; thus obtaining the degradation agent I;
3) preparation of a degrading agent II: slowly adding a pH regulator into the clean water tank, uniformly circulating, sequentially adding an anti-swelling agent, fully circulating, uniformly adding an initiator, and fully circulating to prepare a finished product degradation agent II;
wherein the dissolution speed of the degradation agent I is 0.005-0.007g.min-1The additive can effectively exert the synergistic effect of the medicament to dissolve crude oil adhered on the sandstone surface, improve the permeation and dispersion of the system to the crude oil on the sandstone surface, and the cleaning capacity can reach 90 percent.
The degradation agent II can degrade polymers in a near-wellbore area and a deep stratum, the viscosity reduction rate can reach more than 90%, and the requirements of on-site blockage removal and viscosity reduction can be met.
The application also comprises the application of the degradation agent for removing the polymer blockage of the near wellbore zone of the sand control well of the screen pipe of the polymer injection zone, which comprises the following steps:
a. pressure test of the construction pipeline connected to the ground: the ground construction pipeline is connected to a wellhead casing valve by a pump truck, an oil pipe valve is closed, the pump truck is used for pressurizing the ground construction pipeline, the control pump pressure is less than or equal to 15MPa, the pump truck pressure is qualified when the pressure is reduced to be less than 0.5MPa within 5min of pressure stabilization, a casing extrusion method is adopted for construction, two 700-type pump trucks are used, and the control pump pressure is less than or equal to 15MPa in construction;
b. replacing the well bore treatment fluid by the casing: opening a well bore treatment fluid for replacing oil casing annulus fluid by the oil pipe valve, closing the oil pipe valve after the fluid returns from an oil pipe outlet, wherein the using amount of the well bore treatment fluid is the oil casing annulus volume of the production pipe column depth of the screen pipe sand control well in the polymer injection area;
c. casing squeeze into wellbore treatment fluid: the construction effect can be improved by reducing the surface (interface) tension, and the pumping amount is one third of the volume of the phi 73mm oil pipe in the shaft;
d. squeezing the sleeve into a formation pretreatment liquid: the pumping amount is calculated by 1.5-3 square of each meter of oil layer of the perforation well section, so as to achieve the effect of protecting the oil layer;
e. extruding the sleeve into clear water for isolation: the pumping amount is 1 to 1.5 times;
f. extruding a degrading agent I into the sleeve: the pumping amount is 3-4 directions per meter of oil layer of the perforation well section, and crude oil adhered to the surfaces of a shaft and sandstone can be effectively dissolved;
g. extruding the sleeve into clear water for isolation: the pumping amount is 1 to 1.5 times;
h. extruding a degrading agent II into the sleeve: the pumping amount is 3-4 sides per meter of oil layer of the perforation well section, and the polymer blockage of the sand control well near the well zone of the screen pipe of the polymer injection zone is effectively removed;
i. extruding the sleeve into clear water for replacement: the pumping amount is the sum of the empty volume of the oil sleeve ring and the volume of the sand control screen pipe column phi 73 mm;
j. and (5) closing the well, reacting for 30min, and finishing construction.
Compared with the prior art, the invention has the beneficial effects that:
the Polyacrylamide (PAM) used for the polymer flooding generally has a main chain of C-C bond and a side chain of amido bond or carboxyl, and has a stable structure and is not easy to degrade. Meanwhile, crude oil on the surface of sandstone in the injection zone contains a large amount of alkane, aromatic hydrocarbon, colloid, asphaltene and the like, so that a surfactant combination is creatively adopted in the application, and comprises mixed benzene, OP-10, ethylene glycol monobutyl ether and alkylolamide, the synergistic effect of various medicaments is exerted to the maximum extent, the capability of a solvent for dissolving asphaltene is improved, and the effects of the system on the penetration, dispersion and the like of the crude oil on the surface of sandstone can be achieved; meanwhile, the initiator is added, so that the reaction activation energy is low, the degradation can be initiated at a low temperature in an acid environment, and the degradation rate is high. The system is water-soluble and has high degradation degree on polyacrylamide solution.
The application provides a degradation agent for removing the blockage of a sand well near-well zone of a screen pipe in an injection zone of a loose sandstone reservoir by adopting a reverse extrusion construction method, and a slotted screen pipe (or a wire-wrapped screen pipe and the like) is adopted for removing the blockage problem of a polymer in a sand well near-well zone of a benefited sand production well in the injection zone; the degradation agent is water-soluble, can initiate degradation at a lower temperature, and has good compatibility with the stratum; the degradation agent system has little damage to the stratum, has good oil layer protection characteristic, keeps the core permeability above 88 percent, can improve the polymer injection development effect and prolongs the sand control validity period. The invention applies 15 wells in the Hongkong oil field, the sand control success rate is 100 percent, and the single-well sand control validity period is more than 2 years.
Description of the drawings:
FIG. 1 is a graph showing the appearance of a polymer solution after degradation of a degradation agent in example 3 of the present invention;
fig. 2 is a graph showing the oil production curve of the field oil well in example 3 of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the following preferred embodiments.
Raw materials: benzene blending (Zibo Dongtong chemical Co., Ltd.); OP-10 (Jiangsu Haian petrochemical plant); ethylene glycol monobutyl ether (guangdong international trade limited of Tianjin); alkylolamides (Weifang Xiangyu chemical Co., Ltd.); ammonium persulfate (Jinan national trade chemical Co., Ltd.); ferrous sulfate heptahydrate (jonan renyu chemical limited); potassium chloride (purity: more than 90%); hydrochloric acid (content: 36-38%).
1. Preparation and performance of the degradation agent system:
example 1:
1) preparation of a degradation agent I: firstly, before preparation, a liquid storage tank is connected with a pump truck through a pipeline, a circulating system is established, 10 tons of clear water in the liquid storage tank is fully circulated, 0.063 ton of surfactant combined mixed benzene, 0.8978 ton of OP-100.042 ton and 0.011 ton of ethylene glycol monobutyl ether are slowly added into a feeding funnel of the pump truck, after uniform stirring, 0.026 ton of alkylolamide is added, and full circulation is carried out for 15-20 minutes; then 0.2 ton of potassium chloride is added evenly, and the circulation is carried out for 10 to 15 minutes; thus obtaining the degradation agent I; the results of the performance test of the cleaned crude oil are shown in Table 1.
TABLE 1
| Dissolution rate, g.min-1 | 0.006 |
| Cleaning ability% | 96 |
| Polymer concentration, ppm | 2000 |
2) Preparation of a degrading agent II: 10 tons of clean water in the clean water tank is slowly added with 0.008 ton of hydrochloric acid, the circulation is uniform, 0.15 ton of potassium chloride is sequentially added, the circulation is carried out for 10 to 15 minutes, 0.025 ton of ammonium persulfate serving as an initiator and 0.312 ton of ferrous sulfate heptahydrate are added, and the full circulation is carried out for 15 to 20 minutes, thus preparing a finished product degrading agent II; the results of the viscosity reduction performance test are shown in Table 2.
TABLE 2
| Reaction time | 1h | 2h | 4h | 8h | 12h | 16h |
| Viscosity of phi 600 | 1.6 | 1.6 | 1.5 | 1.5 | 1.4 | 1.4 |
| Viscosity reduction Rate (%) | 91.1 | 91.1 | 91.7 | 91.7 | 92.3 | 92.3 |
Example 2:
1) preparation of a degradation agent I: firstly, before preparation, a liquid storage tank is connected with a pump truck through a pipeline, a circulating system is established, 9 tons of clear water in the liquid storage tank are fully circulated, 0.045 ton of mixed benzene, 0.005 ton of OP-100.021 ton and 0.005 ton of ethylene glycol monobutyl ether are slowly added into a charging funnel of the pump truck, 0.012 ton of alkylolamide is added after uniform stirring, and the full circulation is carried out for 15-20 minutes; then 0.1 ton of potassium chloride is added evenly, and the circulation is carried out for 10 to 15 minutes; thus obtaining the degradation agent I; the performance test results of the cleaning crude oil are shown in Table 3;
TABLE 3
| Dissolution rate, g.min-1 | 0.005 |
| Cleaning ability% | 95 |
| Polymer concentration, ppm | 2000 |
2) Preparation of a degrading agent II: 9 tons of clean water in the clean water tank is slowly added with 0.005 ton of hydrochloric acid, the circulation is uniform, 0.1 ton of potassium chloride is sequentially added, the circulation is carried out for 10 to 15 minutes, 0.012 ton of initiating agent ammonium persulfate and 0.106 ton of ferrous sulfate heptahydrate are added, the full circulation is carried out for 15 to 20 minutes, and then the finished product degradation agent II can be prepared; the viscosity reduction performance test results are shown in Table 4;
TABLE 4
| Reaction time | 1h | 2h | 4h | 8h | 12h | 16h |
| Viscosity of phi 600 | 1.6 | 1.6 | 1.5 | 1.5 | 1.4 | 1.4 |
| Viscosity reduction Rate (%) | 91.3 | 91.3 | 92.0 | 92.0 | 92.6 | 92.6 |
Example 3:
1) preparation of a degradation agent I: firstly, before preparation, a liquid storage tank is connected with a pump truck through a pipeline, a circulating system is established, 9.5 tons of clean water in the liquid storage tank are fully circulated, 0.05 ton of mixed benzene, OP-100.03 tons and 0.08 ton of ethylene glycol monobutyl ether are slowly added into a charging funnel of the pump truck, 0.02 ton of alkylolamide is added after uniform stirring, and the full circulation is carried out for 15-20 minutes; then 0.15 ton of potassium chloride is added evenly, and the circulation is carried out for 10 to 15 minutes; thus obtaining the degradation agent I; the performance test results of the cleaning crude oil are shown in Table 5;
TABLE 5
2) Preparation of a degrading agent II: 9.5 tons of clean water in the clean water tank is slowly added with 0.0065 ton of hydrochloric acid, the circulation is uniform, 0.125 ton of potassium chloride is sequentially added, the circulation lasts for 10 to 15 minutes, 0.02 ton of initiator ammonium persulfate is added, 0.2 ton of ferrous sulfate heptahydrate is added, the full circulation lasts for 15 to 20 minutes, and a finished product of the degradation agent II can be prepared;
the viscosity reduction performance test results are shown in Table 6:
TABLE 6
| Reaction time | 1h | 2h | 4h | 8h | 12h | 16h |
| Viscosity of phi 600 | 1.6 | 1.6 | 1.5 | 1.5 | 1.4 | 1.4 |
| Viscosity reduction Rate (%) | 91.2 | 91.2 | 91.8 | 91.8 | 92.5 | 92.5 |
2. The degradation agent system researched by the invention is water-soluble, can initiate degradation at a lower temperature and has good compatibility with the stratum. A polymer solution prepared indoors at a concentration of 2000ppm and the degradation agent of example 3 are prepared and tested respectively with tap water and formation water, phi 600 viscosities are measured for comparison (initial viscosities are both 18mpa.s), and table 7 shows compatibility of the degradation agent of the invention;
TABLE 7
| Item | Preparation of running water | Formation water preparation |
| Phi 600 viscosity, mPa.S | 1.5 | 1.6 |
| Viscosity reduction rate eta% | 91.7％ | 91.1％ |
3. The degradation agent in example 3 researched by the invention has little damage to the stratum, has good oil layer protection characteristic, and keeps the core permeability above 88%. Table 8 shows the core damage performance of the inventive degradant;
TABLE 8
| |
1 | 2 | 3 |
| Original permeability, U square meter | 0.92 | 5.0 | 20.1 |
| Permeability recovery for square meter with U shape | 0.83 | 4.6 | 17.9 |
| Injury rate% | 10％ | 8％ | 11％ |
4. And (3) field application:
a pumping well in the Ganggang oil field in the Ganggang and the West belongs to a screen pipe sand control well in a unconsolidated sandstone reservoir injection zone. The oil well yield is reduced due to the blockage of a near wellbore zone before the well is degraded again, the daily liquid yield is only 1.24m3, the daily oil yield is only 0.4t, and the stratum contains 70.82% of water.
(1) Site construction and steps:
a. pressure testing of a ground construction pipeline: the ground construction pipeline is connected to a wellhead casing valve by a pump truck, an oil pipe valve is closed, the ground construction pipeline is pressurized by the pump truck, the control pump pressure is less than or equal to 15MPa, the pump truck pressure is reduced to be less than 0.5MPa within 5min of pressure stabilization, the construction is qualified, a casing extrusion method is adopted, two 700-type pump trucks are adopted, and the control pump pressure is less than or equal to 15MPa in the construction process.
b. Replacing the well bore treatment fluid by the casing: well bore treatment fluid is used for replacing oil casing annulus fluid when the oil pipe valve is opened, and the using amount of the treatment fluid is 7m3。
c. Casing squeeze into wellbore treatment fluid: the oil pipe valve is closed, the pumping amount is one third of the volume of the oil pipe with the diameter of 73mm in the shaft, and the using amount is 3m3。
d. Squeezing the sleeve into a formation pretreatment liquid: the pumping amount is 20m3。
e. Extruding clear water into the sleeve: the dosage is 1m3。
f. The cannula was extruded with the degradation agent i of example 3: the design is that the oil layer per meter of the perforation well section is 3-4 square, the liquid quantity is 30m3。
g. Extruding clear water into the sleeve: the dosage is 1m3。
h. The cannula was extruded with the degradation agent ii of example 3: the design is that the oil layer per meter of the perforation well section is 3-4 square, and the dosage is 20m3。
i. Extruding the sleeve into clear water for replacement: the liquid amount is 15m3。
j. And (5) closing the well, reacting for 30min, and finishing construction.
(2) Table 9 shows the construction pump-grouting procedure construction parameters:
TABLE 9
(3) Degradation effect
After the operation, the well normally produces 365 days, the daily liquid production amount is 33.41m3, and the daily oil production amount is 9.75 t. And by 31 days of 12 months and 31 days of 2017, the oil production is restored to 3033t accumulatively, and the crude oil production is increased to 2830t accumulatively.
Figure 2 shows the field well production curve.
The effect statistics of other loose sand screens on the degradation of the polymer plugged well in the sand well near wellbore zone are shown in the following table 10:
watch 10
The experimental data show that: the oil-gas field casing pipe reverse extrusion type degrading agent can effectively degrade polymer blockage of the screen pipe sand control well near wellbore zone through construction of the screen pipe sand control well near wellbore zone polymer blockage well in the loose sandstone injection zone, and has the characteristics of good degradation effect and stable later-stage production after treatment by the process.
The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.
Claims (7)
1. The degradation agent for removing polymer blockage of a sand control well near a wellbore zone of a screen pipe in a polymer injection zone is characterized by comprising the following components in parts by weight: comprises the following components in parts by mass:
degrading agent I: 90-100 parts of clean water, 0.71-1.16 parts of surfactant composition with cleaning effect, 0.12-0.26 part of stabilizer and 1-2 parts of anti-swelling agent;
and (3) a degrading agent II: 90-100 parts of clear water, 1-1.5 parts of anti-swelling agent, 0.05-0.08 part of pH value regulator and 0.12-3.12 parts of initiator.
2. The agent for degrading polymer plugging in near wellbore area of a relief screen of claim 1 wherein said surfactant combination comprises the following components: 0.45-0.63 part of mixed benzene, 0.42-0.42 part of OP-100.21 and 0.05-0.11 part of ethylene glycol monobutyl ether.
3. The agent for degrading polymer plugging in near wellbore area of a screen sand control well of claim 1 wherein the stabilizer is alkylolamide; the anti-swelling agent is potassium chloride; the PH value regulator is hydrochloric acid; the initiator is 0.12-0.25 part of ammonium persulfate and/or 1.06-3.12 parts of ferrous sulfate heptahydrate.
4. A method for preparing a degradation agent for removing polymer blockage of a near wellbore zone of a sand control well of a screen pipe of a polymer injection zone according to claims 1-3, which comprises the following steps:
1) preparation of a degradation agent I: firstly, before preparation, a liquid storage tank is connected with a pump truck through a pipeline, a circulating system is established, clear water in the liquid storage tank is fully circulated, a surfactant combination is slowly added into a charging hopper of the pump truck, and a stabilizer is added after uniform stirring for full circulation; simultaneously adding an anti-swelling agent, and circulating; thus obtaining the degradation agent I;
3) preparation of a degrading agent II: slowly adding a pH regulator into the clean water tank, uniformly circulating, sequentially adding an anti-swelling agent, fully circulating, uniformly adding an initiator, and fully circulating to obtain a finished product degradation agent II.
5. The method for preparing the degradation agent for relieving the polymer blockage of the sand control well near the wellbore area of the screen pipe of the polymer injection area according to claim 4, wherein the dissolution speed of the degradation agent I is 0.005-0.007g.min-1The additive can effectively exert the synergistic effect of the medicament to dissolve crude oil adhered on the sandstone surface, improve the permeation and dispersion of the system to the crude oil on the sandstone surface, and the cleaning capacity can reach 90 percent.
6. The preparation method of the degradation agent for removing the polymer blockage of the sand control well near the wellbore zone of the screen pipe in the polymer injection zone according to claim 4, wherein the degradation agent II can degrade polymers near the wellbore zone and at the deep position of a stratum, the viscosity reduction rate can reach more than 90%, and the requirements of on-site blockage removal and viscosity reduction can be met.
7. Use of a polymer plugging-releasing degradant for sand control wells near wellbore area of a screen of a polymer injection zone according to any of claims 1-3, comprising the steps of:
a. pressure test of the construction pipeline connected to the ground: the ground construction pipeline is connected to a wellhead casing valve by a pump truck, an oil pipe valve is closed, the pump truck is used for pressurizing the ground construction pipeline, the control pump pressure is less than or equal to 15MPa, the pump truck pressure is qualified when the pressure is reduced to be less than 0.5MPa within 5min of pressure stabilization, a casing extrusion method is adopted for construction, two 700-type pump trucks are used, and the control pump pressure is less than or equal to 15MPa in construction;
b. replacing the well bore treatment fluid by the casing: opening a well bore treatment fluid for replacing oil casing annulus fluid by the oil pipe valve, closing the oil pipe valve after the fluid returns from an oil pipe outlet, wherein the using amount of the well bore treatment fluid is the oil casing annulus volume of the production pipe column depth of the screen pipe sand control well in the polymer injection area;
c. casing squeeze into wellbore treatment fluid: the construction effect can be improved by reducing the surface (interface) tension, and the pumping amount is one third of the volume of the phi 73mm oil pipe in the shaft;
d. squeezing the sleeve into a formation pretreatment liquid: the pumping amount is calculated by 1.5-3 square of each meter of oil layer of the perforation well section, so as to achieve the effect of protecting the oil layer;
e. extruding the sleeve into clear water for isolation: the pumping amount is 1 to 1.5 times;
f. extruding a degrading agent I into the sleeve: the pumping amount is 3-4 directions per meter of oil layer of the perforation well section, and crude oil adhered to the surfaces of a shaft and sandstone can be effectively dissolved;
g. extruding the sleeve into clear water for isolation: the pumping amount is 1 to 1.5 times;
h. extruding a degrading agent II into the sleeve: the pumping amount is 3-4 sides per meter of oil layer of the perforation well section, and the polymer blockage of the sand control well near the well zone of the screen pipe of the polymer injection zone is effectively removed;
i. extruding the sleeve into clear water for replacement: the pumping amount is the sum of the empty volume of the oil sleeve ring and the volume of the sand control screen pipe column phi 73 mm;
j. and (5) closing the well, reacting for 30min, and finishing construction.
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Effective date of registration: 20201104 Address after: 300000 No. three, Dagang Oilfield, Binhai New Area, Tianjin Applicant after: DAGANG OILFIELD GROUP Co.,Ltd. Applicant after: CHINA NATIONAL PETROLEUM Corp. Address before: 300 000 Dagang No.3 hospital, Binhai New Area, Tianjin Applicant before: DAGANG OILFIELD GROUP Co.,Ltd. |
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