CN112796728A - Acid fracturing method for improving water yield of limestone reservoir geothermal well - Google Patents
Acid fracturing method for improving water yield of limestone reservoir geothermal well Download PDFInfo
- Publication number
- CN112796728A CN112796728A CN201911108732.1A CN201911108732A CN112796728A CN 112796728 A CN112796728 A CN 112796728A CN 201911108732 A CN201911108732 A CN 201911108732A CN 112796728 A CN112796728 A CN 112796728A
- Authority
- CN
- China
- Prior art keywords
- acid
- water
- well
- gelled
- linear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002253 acid Substances 0.000 title claims abstract description 225
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 127
- 238000000034 method Methods 0.000 title claims abstract description 53
- 235000019738 Limestone Nutrition 0.000 title claims abstract description 15
- 239000006028 limestone Substances 0.000 title claims abstract description 15
- 239000007788 liquid Substances 0.000 claims abstract description 78
- 238000010276 construction Methods 0.000 claims abstract description 38
- 239000003292 glue Substances 0.000 claims abstract description 38
- 238000006073 displacement reaction Methods 0.000 claims abstract description 31
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 88
- 239000012530 fluid Substances 0.000 claims description 49
- 239000010410 layer Substances 0.000 claims description 45
- 239000000654 additive Substances 0.000 claims description 28
- 230000000996 additive effect Effects 0.000 claims description 28
- 238000002347 injection Methods 0.000 claims description 28
- 239000007924 injection Substances 0.000 claims description 28
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 27
- 238000005260 corrosion Methods 0.000 claims description 26
- 230000007797 corrosion Effects 0.000 claims description 26
- 239000003112 inhibitor Substances 0.000 claims description 26
- 239000003381 stabilizer Substances 0.000 claims description 25
- 229910052742 iron Inorganic materials 0.000 claims description 24
- -1 iron ion Chemical class 0.000 claims description 22
- 206010017076 Fracture Diseases 0.000 claims description 21
- 238000004519 manufacturing process Methods 0.000 claims description 20
- 208000010392 Bone Fractures Diseases 0.000 claims description 19
- 238000011161 development Methods 0.000 claims description 15
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 14
- 239000011435 rock Substances 0.000 claims description 12
- 239000011229 interlayer Substances 0.000 claims description 10
- 238000005553 drilling Methods 0.000 claims description 9
- 239000003349 gelling agent Substances 0.000 claims description 8
- 229920000642 polymer Polymers 0.000 claims description 8
- 229920013818 hydroxypropyl guar gum Polymers 0.000 claims description 7
- 230000004048 modification Effects 0.000 claims description 7
- 238000012986 modification Methods 0.000 claims description 7
- 230000000844 anti-bacterial effect Effects 0.000 claims description 6
- 239000003899 bactericide agent Substances 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 239000000356 contaminant Substances 0.000 claims description 2
- 238000002203 pretreatment Methods 0.000 claims 1
- 238000005406 washing Methods 0.000 description 25
- 230000008569 process Effects 0.000 description 16
- 230000020477 pH reduction Effects 0.000 description 15
- 230000001965 increasing effect Effects 0.000 description 14
- 239000003795 chemical substances by application Substances 0.000 description 12
- 238000005086 pumping Methods 0.000 description 12
- 239000000853 adhesive Substances 0.000 description 9
- 230000001070 adhesive effect Effects 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000005530 etching Methods 0.000 description 6
- 238000011010 flushing procedure Methods 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 239000003344 environmental pollutant Substances 0.000 description 5
- 231100000719 pollutant Toxicity 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 238000003825 pressing Methods 0.000 description 4
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 239000007767 bonding agent Substances 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- WTDHULULXKLSOZ-UHFFFAOYSA-N Hydroxylamine hydrochloride Chemical compound Cl.ON WTDHULULXKLSOZ-UHFFFAOYSA-N 0.000 description 2
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 2
- 230000002579 anti-swelling effect Effects 0.000 description 2
- 239000010459 dolomite Substances 0.000 description 2
- 229910000514 dolomite Inorganic materials 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000002736 nonionic surfactant Substances 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000036632 reaction speed Effects 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 238000007790 scraping Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 241000283690 Bos taurus Species 0.000 description 1
- 241000282836 Camelus dromedarius Species 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229940077388 benzenesulfonate Drugs 0.000 description 1
- 229920006317 cationic polymer Polymers 0.000 description 1
- 239000007859 condensation product Substances 0.000 description 1
- 229920006037 cross link polymer Polymers 0.000 description 1
- JRBPAEWTRLWTQC-UHFFFAOYSA-N dodecylamine Chemical compound CCCCCCCCCCCCN JRBPAEWTRLWTQC-UHFFFAOYSA-N 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229960002413 ferric citrate Drugs 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 125000002636 imidazolinyl group Chemical group 0.000 description 1
- NPFOYSMITVOQOS-UHFFFAOYSA-K iron(III) citrate Chemical compound [Fe+3].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NPFOYSMITVOQOS-UHFFFAOYSA-K 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- DVEKCXOJTLDBFE-UHFFFAOYSA-N n-dodecyl-n,n-dimethylglycinate Chemical group CCCCCCCCCCCC[N+](C)(C)CC([O-])=O DVEKCXOJTLDBFE-UHFFFAOYSA-N 0.000 description 1
- 150000007524 organic acids Chemical group 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- CTSLXHKWHWQRSH-UHFFFAOYSA-N oxalyl chloride Substances ClC(=O)C(Cl)=O CTSLXHKWHWQRSH-UHFFFAOYSA-N 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 235000020681 well water Nutrition 0.000 description 1
- 239000002349 well water 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
-
- 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
- C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
-
- 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
- C09K8/62—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
-
- 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
- C09K8/62—Compositions for forming crevices or fractures
- C09K8/72—Eroding chemicals, e.g. acids
- C09K8/725—Compositions containing polymers
-
- 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
- C09K8/62—Compositions for forming crevices or fractures
- C09K8/72—Eroding chemicals, e.g. acids
- C09K8/74—Eroding chemicals, e.g. acids combined with additives added for specific purposes
-
- 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
- C09K8/84—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
- C09K8/905—Biopolymers
-
- 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
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Mining & Mineral Resources (AREA)
- Geology (AREA)
- General Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Geochemistry & Mineralogy (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Mechanical Engineering (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
The invention discloses an acid fracturing method for improving water yield of a limestone reservoir geothermal well, which comprises the following steps: (1) pretreating the stratum by using pretreatment liquid; (2) carrying out acid fracturing construction to form artificial cracks so as to modify a water producing layer; wherein, the acid fracturing construction comprises alternately injecting linear glue and gelled acid, then injecting closed acid, and finally injecting displacement liquid. The technical scheme of the invention effectively reforms the heat reservoir, improves the water yield of the low-yield geothermal well and meets the heat supply requirement.
Description
Technical Field
The invention belongs to the technical field of yield increase of limestone geothermal wells, and particularly relates to an acid fracturing method for improving water yield of a limestone reservoir geothermal well.
Background
The Shanxi Taiyuan geothermal reservoir belongs to a carbonate reservoir, has strong heterogeneity, uneven slit hole development, partial geothermal wells are far away from a fault, the connectivity of cracks or slits of the geothermal reservoir is poor, a water outlet channel is not smooth, the water yield is small, the water yield is quickly attenuated, and the heat supply requirement cannot be met. Deep acid fracturing modification is needed, acid etching grooves with high flow conductivity are formed in the artificial cracks, and the acid etching grooves are communicated with a remote geothermal water reservoir body, so that the purpose of increasing water yield is achieved. According to statistics, one third of geothermal well water yield in the Taiyuan region is lower than 50m3H, cannot be economically exploited. The geothermal well has higher construction cost, and once the water yield is not ideal, great economic loss can be caused to investors.
In the past, technologies such as acidizing well washing, chemical fracturing well washing, high-pressure acidizing, hydrochloric acid fracturing and the like are mainly adopted to improve the water yield of the geothermal well.
The patent application with the application number of 2016100701693 discloses an ancient carbonate thermal reservoir chemical fracturing well washing process, belongs to the technical field of well washing processes, and adopts self-madeThe well washing acid agent is combined with high-pressure well washing, the well washing acid agent is injected into a hole section needing acidizing well washing treatment by a high-pressure pump truck, clear water is pressed in until the well washing acid agent stored in the drill rod is completely pressed into the well, the acid injection port and the blowout port are kept closed for 1.5-2.0 hours, finally pressure is relieved, reaction residues are discharged, a wellhead device is disassembled, the drill rod is extracted, and the well washing acid agent is discharged into a water pump for pumping and washing. The ancient carbonate thermal reservoir chemical fracturing well-flushing process increases the fracture rate of the thermal reservoir by using high pressure, simultaneously leads the fracture connectivity to be better by using the chemical action of hydrochloric acid, improves the storage space and the runoff channel of underground hot water, and improves the water yield of a geothermal well. The invention relates to an ancient carbonate thermal reservoir chemical fracturing well-flushing process, which comprises the following steps: 1) putting the drill rod into a hole section needing acidizing and well washing treatment; 2) welding a well mouth, and installing an acid injection port with a high-pressure valve and a blowout port to ensure that the valve of the acid injection port is in an open state and the valve of the blowout port is in a completely closed state; 3) connecting the high-pressure pump truck with an acid injection port by using a high-pressure steel pipe, and checking the sealing effect; 4) starting a high-pressure pump truck, and pressing a well acid washing agent into a well from an acid injection port; 5) continuously pressing clear water into the well until the well-flushing acid agent stored in the drill rod is completely pressed into the well; 6) completely closing the valve of the acid injection port, and disconnecting the high-pressure pump truck from the acid injection port; 7) keeping the acid injection port and the blow-off port closed for 1.5-2.0 h; 8) opening a blowout port valve to release pressure, starting a pressure fan later, connecting the pressure fan with an acid injection port, opening the acid injection port valve, and utilizing the pressure fan to flow back carbonate reaction residues in the well; 9) and after the reaction residues are discharged completely, disassembling the wellhead device, extracting the drill rod, and putting into a water pump for pumping and washing. The well washing acid agent hydrochloric acid, the corrosion inhibitor, the iron stabilizer and the cleanup additive are used in an amount of 60-80 tons according to different drilling depths, and the mass ratio of the corrosion inhibitor to the hydrochloric acid is as follows: 1: 100-1: 50, the mass ratio of the iron stabilizer to the hydrochloric acid is as follows: 0.5: 100-1: 100, the mass ratio of the cleanup additive to the hydrochloric acid is as follows: 0.5: 100-1: 100. the concentration of the hydrochloric acid is 10-20%. The corrosion inhibitor is imidazoline corrosion inhibitor, and the use concentration is 1%. The iron stabilizer consists of ethylenediamine tetraacetic acid, citric acid, oxalic acid and hydroxylamine hydrochloride, and the use concentration is 0.5%. The cleanup additive is a fluorine-containing nonionic surfactant, and the use concentration is 0.5%. The process is as followsThe yield of the geothermal well in the Lunan near-Yi area after the well washing is 10m from the front of the well washing3Increase of h to 36m3H; the produced water quantity after the well washing of a certain geothermal well in Jining of Luxi province is 25m from the position before the well washing3Increase of h to 43m3H is used as the reference value. The ancient carbonate thermal reservoir chemical fracturing well-flushing process disclosed in the patent application utilizes high pressure to increase the fracture rate of a thermal reservoir, utilizes the chemical action of hydrochloric acid to enable the fracture connectivity to be better, and improves the water yield of a geothermal well. However, the hydrochloric acid used in the process has high reaction speed with carbonate, has limited action distance, cannot communicate with fractures or crevices at far positions, can only be used for modifying a near wellbore zone, and has poor water increasing effect.
Document 1 application of acid fracturing technology in geothermal wells discloses a hydrochloric acid fracturing technology, which is mainly used for removing mud pollution. Pumping hydrochloric acid solution 120m in WR95 geothermal well by positive extrusion method under constant pressure (less than or equal to 20MPa)3The formula is as follows: 72t of 31 percent hydrochloric acid, 3.0t of corrosion inhibitor, 2.0t of cleanup additive, 2.0t of iron ion stabilizer, 3.0t of anti-swelling agent and 50.4m3Clean water, replacing clean water by 6.2m3. After the well is acid-pressed, the water yield is 10.38m before acidification3H is ramped up to 95.67m3H is used as the reference value. Document 2 application analysis of acidizing hydraulic technology in geothermal yield increase discloses a hydrochloric acid fracturing process, in which a normal extrusion method is adopted to pump 100m hydrochloric acid solution with constant pressure (less than or equal to 20MPa) in an NKR-24D geothermal well3The formula is as follows: 72t 31% HCl +2.0t PH-101 corrosion inhibitor +2.0t PPZ-1 cleanup additive +1.0t PWT-1 iron ion stabilizer +2.0t PH-303 anti-swelling agent +40.0m3Clean water, replacing clean water by 14m3After the well is acid-fracturing, the water yield is up to 47.33m before acidification3H is ramped up to 119.33m3H is used as the reference value. The water yield is not obviously improved after the same process is applied to the JNR-09 geothermal well. Document 3 "increasing water production of deep geothermal wells using high pressure acidizing" discloses a method for increasing water yield of thermal reservoirs using high pressure acidizing. The technology adopts 22% hydrochloric acid, and the hydrochloric acid is pumped into the stratum by using an acid pressing vehicle to erode the stratum and remove the stratum blockage. 80m of hydrochloric acid solution is pumped and injected into one-opening limestone geothermal well in Songshan area3After the well is acidified, the water yield is 3.5m before acidification3The h is increased to 26m3H is used as the reference value. Document 4 acidified well flushing on Hebei cattle camel ballastAn application of two wells in a hot field discloses a hydrochloric acid well washing process, which comprises the following steps: 18% of HCl, 2% of 7812% of corrosion inhibitor, 0.5% of ferric citrate ion stabilizer, 1% of dodecylamine retarder and sodium alkyl benzene sulfonate or washing powder cleanup additive. Respectively pumping 35m under the fracture pressure in a high-porosity and high-permeability dolomite t and s two-mouth dolomite geothermal well blocked by mud pollution3And 25m3Washing the well with hydrochloric acid, wherein the unit water yield after washing the well is respectively 1.75m before washing the well3Increase of/h.m to 6.23m3/h.m and 0.91m3Increase of/h.m to 4.91m3And/h.m. In summary, the hydrochloric acid fracturing or hydrochloric acid well flushing processes disclosed in documents 1 to 4 can only remove the pollution blockage of the drilling mud in the near wellbore zone and improve the permeability of the near wellbore zone. These measures have some effect in increasing water production, but also have obvious disadvantages and shortcomings: firstly, the reaction speed of the hydrochloric acid and the carbonate rock is high, most of the hydrochloric acid and the carbonate rock stay near the well wall and cannot go deep into a water-bearing stratum, namely, the acidification radius is small, and the water increasing effect is limited; and secondly, the acidification scale is small, the thermal reservoir cannot be effectively transformed, the fracture or the fracture-cave at a far distance can be communicated, the water increasing effect is limited, and the effect of removing the blockage of the near wellbore zone or improving the permeability of the near wellbore zone is better.
Disclosure of Invention
The invention aims to provide an acid fracturing process method for improving the water yield of a limestone geothermal well, which aims at solving the problems of poor physical property, strong heterogeneity, poor connectivity with a water body, low water yield and poor yield increasing effect of the traditional acid pickling or acidizing process of partial limestone geothermal wells, effectively improves the thermal reservoir, improves the water yield of the low-yield geothermal wells and meets the heat supply requirement.
In order to achieve the above object, the present invention provides an acid fracturing method for increasing water production of a limestone reservoir geothermal well, comprising:
(1) pretreating the stratum by using pretreatment liquid;
(2) carrying out acid fracturing construction to form artificial cracks so as to modify a water producing layer; the acid fracturing construction comprises alternately injecting linear glue and gelled acid, then injecting closed acid, and finally injecting a displacement fluid.
The technical scheme of the invention has the following beneficial effects:
according to the acid fracturing method provided by the invention, the parameters of liquidity, liquid quantity and discharge capacity of each construction stage are optimized, and firstly, hydrochloric acid pretreatment liquid is adopted to remove drilling pollutants in a near-wellbore area; then, a construction process of alternately injecting linear glue and gelled acid in three stages is adopted, so that the liquid filtration can be reduced, and H in acid liquor can be reduced+The mass transfer speed of the method achieves the purposes of making long cracks and increasing the effective acid etching reaction distance of the acid liquor, and artificial long cracks with high flow conductivity are formed in a thermal reservoir; and then closed acid is adopted to further increase the crack flow conductivity and improve the acid fracturing effect. Therefore, natural fractures or cracks are communicated, the flow conductivity of a thermal reservoir is improved, the thermal reservoir is effectively improved, the water yield is increased, and the problems of poor physical property, strong heterogeneity, poor connectivity with a water body and low water yield of the limestone geothermal well are solved. 3 wells are applied on site, and the water yield of a single well reaches 52.2-130m after measures are taken3The water yield is 3-6 times of that before the measures, and the acid washing and acidifying process is superior.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Detailed Description
Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The invention provides an acid fracturing method for improving water yield of a limestone reservoir geothermal well, which comprises the following steps:
(1) pretreating the stratum by using pretreatment liquid;
(2) carrying out acid fracturing construction to form artificial cracks so as to modify a water producing layer; the acid fracturing construction comprises alternately injecting linear glue and gelled acid, then injecting closed acid, and finally injecting a displacement fluid.
In the invention, the acid fracturing construction is carried out on the potential layer of the low-heat-production reservoir, firstly, the pretreatment solution is adopted,removing drilling pollutants from a near wellbore zone; then, a construction process of alternately injecting linear glue and gelled acid in three stages is adopted, so that the liquid filtration can be reduced, and H in acid liquor can be reduced+The mass transfer speed of the method achieves the purposes of making long cracks and increasing the effective acid etching reaction distance of the acid liquor, and artificial long cracks with high flow conductivity are formed in a thermal reservoir; then, closed acid is adopted to further increase the crack flow conductivity and improve the acid fracturing effect; and finally, replacing the active water (displacement liquid) to displace the acid liquid to the stratum. The fracture conductivity can be increased by adopting closed acid acidizing, the conductivity of the near wellbore zone can be improved by 3 times by adopting closed acid fracturing, and the acid fracturing effect is further improved. The length of the optimized artificial crack is 110-150m, and the height is 60-80 m.
In the invention, before injecting the pretreatment liquid and performing acid fracturing construction, some conventional preliminary preparation procedures are also included, for example, the method can comprise the following steps: 1) erecting the operation derrick, dismantling the original wellhead, modifying the original wellhead, and installing the operation construction wellhead; 2) the scraper is lowered to the bottom of the technical casing, and the scraping pipe column is taken out after repeatedly scraping the well section above the bottom and 10m above the setting position of the packer; 3) setting the construction pipe column, setting the packer and checking the seal; 4) installing an acid fracturing well head, and firmly fixing by using a ground anchor and a guy rope; 5) and (5) performing acid swing and pump pressing and pressure testing.
According to the present invention, it is preferable that the following process is further included before the step (1): and selecting the geothermal production well to be subjected to acid fracturing modification based on the potential characteristics of the low-yield well and the reservoir characteristics of the low-yield well.
According to the present invention, preferably, the potential characteristics are composed of the following characteristics (1) to (3):
(1) the linear well distance between the geothermal production well and the water source reservoir body is less than 300 m;
(2) the geothermal production well and the water layer of the peripheral geothermal well have similar reservoir characteristics, and the water yield of the adjacent well is more than 60m3/h；
(3) The sum of the lengths of the first-type and second-type fracture development intervals is more than 10 m.
According to the invention, preferably, the reservoir characteristics consist of the following (1) to (3):
(1) the content of carbonate rock in the rock of the water producing layer is more than 80 percent; and the sum of the lengths of the first-class and second-class fracture development intervals is more than 10 m;
(2) the temperature of the water producing layer is 50-90 ℃;
(3) the stress difference between the water producing layer and the upper interlayer and the stress difference between the water producing layer and the lower interlayer are both 3-5 MPa.
In the invention, the low-heat-production reservoir stratum potential layer is a first-class or second-class crack development layer section (namely a first-class or second-class potential layer), the water layer depth of the first-class or second-class crack development layer section is 1500-2500m, and the water yield is 30m3The ratio of the reaction time to the reaction time is less than h.
According to the invention, the pretreatment of the formation with the pretreatment fluid is preferably to remove near wellbore drilling contaminants with the pretreatment fluid.
According to the present invention, preferably, the alternately injected linear glue and gelled acid are three-stage alternately injected linear glue and gelled acid; the three-stage alternate injection of the linear glue and the gelled acid is sequentially injection of the linear glue, the gelled acid, the linear glue and the gelled acid.
In the invention, high-viscosity linear glue (acid fracturing prepad fluid) and gelled acid (acid fracturing working fluid) are alternately injected in three stages, namely: linear gum-gelled acid-linear gum-gelled acid. The process can improve the seam making efficiency, prolong the action distance of the acid liquor, and improve the liquid efficiency by 140 percent compared with single-stage injection by multi-stage injection.
According to the invention, preferably, the injection volume ratio of the linear glue injected alternately in three stages is (5-7): (4-6): (3-4);
the injection volume ratio of the gelled acid injected alternately in three stages is (4-6) to (3-5) to (3-4).
The liquid injection volume used in each process step of the acid fracturing method can be designed according to the specific construction reservoir condition; wherein the injection volume of the pretreatment liquid is preferably 30-50m3(ii) a The three-stage alternate injection of the linear gel (acid fracturing head fluid) and the gelled acid (acid fracturing working fluid) is preferably performed in sequence: injecting 50-70m3Injecting 40-60m of linear glue3Injecting 40-60m of gelling acid3Injecting 30-50m of linear glue3Injecting 30-40m of gelling acid3Linear glue ofInto 30-40m3The gelling acid of (1); the injection volume of the closed acid is preferably 20-30m3(ii) a The injection volume of the displacement fluid (tubing internal volume + wellbore volume below packer to bottom boundary of the modified zone) is preferably 9-15m3。
In the invention, each level of linear glue (acid fracturing prepad liquid) is used for making cracks, each level of gelled acid (acid fracturing working liquid) is used for etching cracks, closed acid is used for further etching cracks, and displacing liquid is used for displacing acid liquid to a stratum.
In the invention, after the process of injecting the displacement fluid is finished, the pump is usually stopped, and the well is shut down for reaction for several hours, preferably 4-6 hours, so as to better realize artificial seam making.
According to the present invention, it is preferable that the discharge amount of the pretreatment liquid injected is 2.0 to 2.5m3Min, the discharge capacity of injected linear glue is 3.5-4.0m3Min, the discharge capacity of the injected gelled acid is 3.5-4.0m3Min, the discharge of injected closed acid is 2.0-2.5m3Min, displacement of the injected displacement liquid is 2.0-2.5m3/min。
According to the present invention, preferably, the pretreatment liquid includes, based on the total weight of the pretreatment liquid: 18-25 wt% of hydrochloric acid, 0.7-1.5 wt% of acidizing corrosion inhibitor, 0.7-1.5 wt% of iron ion stabilizer, 0.1-0.3 wt% of cleanup additive and the balance of water;
based on the total weight of the linear glue, the linear glue comprises 0.3-0.5 wt% of hydroxypropyl guar gum, 0.1-0.2 wt% of bactericide, 0.1-0.3 wt% of cleanup additive and the balance of water;
the gelling acid comprises, based on the total weight of the gelling acid: 15-20 wt% of hydrochloric acid, 0.7-0.9 wt% of polymer gelling agent, 1-2 wt% of acidizing corrosion inhibitor, 1-2 wt% of iron ion stabilizer, 0.2-0.3 wt% of cleanup additive and the balance of water;
the occlusive acid comprises, based on total weight of the occlusive acid: 16-20 wt% of hydrochloric acid, 1-2 wt% of acidizing corrosion inhibitor, 1-2 wt% of iron ion stabilizer, 0.2-0.3 wt% of cleanup additive and the balance of water;
the displacement fluid comprises, based on the total weight of the displacement fluid: 0.2 to 0.3 weight percent of discharge assistant and the balance of water.
In the invention, the pretreatment solution, the linear glue, the gelled acid, the closed acid and the displacement solution are prepared from the following raw materials: the hydrochloric acid is industrial hydrochloric acid with the mass concentration of 31%. The acidizing corrosion inhibitor can be selected from the existing acidizing corrosion inhibitors for water wells, or the acidizing corrosion inhibitors disclosed in the patent application with the publication number of CN 104109529A. The iron ion stabilizer can be an iron ion stabilizer commonly used in the field, and can also be selected from an iron ion stabilizer for acidification disclosed in the publication No. CN 104109530A. The cleanup additive is a nonionic surfactant. Hydroxypropyl guar gum is a first-grade industrial product. The polymer gelling agent can be a polymer gelling agent commonly used in the art, and can also be a high-temperature resistant acidic cross-linked polymer thickening agent disclosed in the granted patent No. CN 104109219B.
According to the invention, preferably, the linear glue has an apparent viscosity of 27 to 55mpa.s, a pH of 7 to 8;
the apparent viscosity of the gelled acid is 25-28 mPa.s; the acid-etched crack flow conductivity of the gelled acid is 35-40 mu m2.cm。
The invention is further illustrated by the following examples:
the hydrochloric acid used in the following examples is an industrial product hydrochloric acid with a mass concentration of 31% produced by Sanjiang petroleum technology services Limited liability company in Nanyang; the bactericide is an industrial formaldehyde aqueous solution with the mass concentration of 37 percent produced by Sanjiang petroleum technology service Limited liability company in Nanyang city; the hydroxypropyl guar gum is an industrial product produced by Dongyngjia Yiyi chemical Co Ltd, and the model is GRJ-11; the cleanup additive is dodecyl dimethyl betaine, and is purchased from Dongying Yiyi chemical Co., Ltd; the acidizing corrosion inhibitor is a condensation product of aldehyde, ketone and amine, and is purchased from Shandong Dongying Square chemical Co., Ltd, and the mark is GXS; the iron ion stabilizer is organic acid and salt thereof, is purchased from Shandong Dongying Ci chemical Co., Ltd, and has a brand number of FW-20; the polymer gelling agent is a polyacrylamide-based organic cationic polymer available from Puyang, Henan province, Rongtai chemical Co., Ltd., model number DL-8.
Example 1
The implementation provides an acid fracturing method for improving the yield of a limestone reservoir geothermal well, aiming at an LSXS-3 well, and comprising the following steps of:
1. and selecting the geothermal production well to be subjected to acid fracturing modification based on the potential characteristics of the low-yield well and the reservoir characteristics of the low-yield well.
Wherein the potential characteristics are composed of the following characteristics (1) to (3):
(1) the linear well spacing between the geothermal production well and the water source reservoir is 110 m;
(2) the geothermal production well and the water layer of the peripheral geothermal well have similar reservoir characteristics, and the water yield of the adjacent well LSXS-6 is 120m3/h；
(3) The sum of the lengths of the first and second fracture development intervals was 22 m.
The reservoir characteristics are composed of the following characteristics (1) to (3):
(1) the content of carbonate rock in the rock of the water producing layer is 93 percent; and the sum of the lengths of the first-class and second-class fracture development layer sections is 22 mm;
(2) the temperature of a water producing layer is 55 ℃;
(3) the stress difference between the water producing layer and the upper interlayer and the stress difference between the water producing layer and the lower interlayer are both 3.4 MPa.
2. And (4) removing the drilling pollutants in the near wellbore zone by using a pretreatment fluid.
(1) Based on the total weight of the pretreatment liquid, the pretreatment liquid consists of the following components: 20 wt% of hydrochloric acid, 1 wt% of acidizing corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water.
(2) The dosage of the pretreatment liquid is calculated according to the treatment radius 3m of the acid fracturing layer section.
3. And carrying out acid fracturing construction to form artificial cracks so as to reform the water producing layer.
(1) The working fluid used for acid fracturing construction consists of pad fluid (linear glue), gelled acid, closed acid and displacement fluid.
(2) Acid fracturing stage of acid fracturing construction: the method comprises the following steps of sequentially forming a pre-liquid (linear gel) 1 stage, a working liquid (gelled acid) 1 stage, a pre-liquid (linear gel) 2 stage, a working liquid (gelled acid) 2 stage, a pre-liquid (linear gel) 3 stage and a working liquid (gelled acid) 3 stage, wherein the volume ratio of liquid pumping quantities of the pre-liquid 1 stage, the pre-liquid 2 stage and the pre-liquid 3 stage is 6.5: 4.5: 3; the volume ratio of the liquid pumping amount of the gelled acid 1 stage, the gelled acid 2 stage and the gelled acid 3 stage is 5.5: 4.5: 3.
(3) and (3) a closed acidification stage of acid fracturing construction: the closed acid is squeezed into the stratum under the stratum closed pressure, and the dosage is 5m of fracture volume of the near wellbore of the stratum.
(4) And (3) a displacing liquid stage of acid fracturing construction: the displacement liquid is active water, and the using amount of the displacement liquid is 1.1 times of the volume of the construction squeeze-injection pipe column.
The adhesive comprises a linear adhesive and a bonding agent, wherein the linear adhesive consists of the following components in percentage by weight: 0.3 wt% of hydroxypropyl guar gum, 0.2 wt% of bactericide, 0.2 wt% of cleanup additive and the balance of water. The apparent viscosity of the linear gel was 30mPa.s, pH 7.5.
The gelling acid consists of the following components, based on the total weight of the gelling acid: 18 wt% of hydrochloric acid with the mass concentration of 31%, 0.8 wt% of polymer gelling agent, 1 wt% of acidification corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water. The gelling acid has an apparent viscosity of 27.5 mpa.s; the acid-etched crack flow conductivity of the gelled acid is 38 mu m2.cm。
The occlusive acid consists of the following components in percentage by total weight of the occlusive acid: 20 wt% of hydrochloric acid with the mass concentration of 31%, 1 wt% of acidification corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water.
The displacement fluid consists of the following components (i.e., active water) by total weight: 0.2 wt% of discharge assistant agent and the balance of water.
Specific pump parameters are shown in table 1:
table 1 construction parameters of the acid fracturing method of example 1
| Serial number | Pumping stage | Discharge capacity m3/min | Volume m3 | Type of working fluid |
| 1 | Pretreatment liquid | 2 | 40 | Pretreatment liquid |
| 2 | Acid fracturing pad fluid | 4 | 65 | Linear glue |
| 3 | Acid fracturing working fluid | 4 | 55 | Gelled acid |
| 4 | Acid fracturing pad fluid | 4 | 45 | Linear glue |
| 5 | Acid fracturing working fluid | 4 | 45 | Gelled acid |
| 6 | Acid fracturing pad fluid | 4 | 30 | Linear glue |
| 7 | Acid fracturing working fluid | 4 | 30 | Gelled acid |
| 8 | Closed acid | 2 | 30 | Closed acid |
| 9 | Displacement replacement | 2 | 12.4 | Active water |
Example 2
The implementation provides an acid fracturing method for improving the yield of a limestone reservoir geothermal well, which aims at an HTTZ-1 well and comprises the following steps:
1. and selecting the geothermal production well to be subjected to acid fracturing modification based on the potential characteristics of the low-yield well and the reservoir characteristics of the low-yield well.
Wherein the potential characteristics are composed of the following characteristics (1) to (3):
(1) the linear well spacing between the geothermal production well and the water source reservoir is 260 m;
(2) the geothermal production well and the water layer of the peripheral geothermal well have similar reservoir characteristics, and the HTTZ-3 water yield of the adjacent well is 70m3/h；
(3) The sum of the lengths of the first and second fracture development intervals was 28 m.
The reservoir characteristics are composed of the following characteristics (1) to (3):
(1) the content of carbonate rock in the rock of the water producing layer is 95 percent; and the sum of the lengths of the first-class crack development layer and the second-class crack development layer is 28 mm;
(2) the temperature of a water producing layer is 59 ℃;
(3) the stress difference between the water producing layer and the upper interlayer and the stress difference between the water producing layer and the lower interlayer are both 3.6 MPa.
2. And (4) removing the drilling pollutants in the near wellbore zone by using a pretreatment fluid.
(1) Based on the total weight of the pretreatment liquid, the pretreatment liquid consists of the following components: 20 wt% of hydrochloric acid, 1 wt% of acidizing corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water.
(2) The dosage of the pretreatment liquid is calculated according to the treatment radius 3m of the acid fracturing layer section.
3. And carrying out acid fracturing construction to form artificial cracks so as to reform the water producing layer.
(1) The working fluid used for acid fracturing construction consists of pad fluid (linear glue), gelled acid, closed acid and displacement fluid.
(2) Acid fracturing stage of acid fracturing construction: the method comprises the following steps of sequentially forming a pre-liquid (linear gel) 1 stage, a working liquid (gelled acid) 1 stage, a pre-liquid (linear gel) 2 stage, a working liquid (gelled acid) 2 stage, a pre-liquid (linear gel) 3 stage and a working liquid (gelled acid) 3 stage, wherein the volume ratio of liquid pumping quantities of the pre-liquid 1 stage, the pre-liquid 2 stage and the pre-liquid 3 stage is 7: 6: 4; the volume ratio of the liquid pumping amount of the gelling acid 1 stage, the gelling acid 2 stage and the gelling acid 3 stage is 6: 5: 4.
(3) and (3) a closed acidification stage of acid fracturing construction: the closed acid is squeezed into the stratum under the stratum closed pressure, and the dosage is 5m of fracture volume of the near wellbore of the stratum.
(4) And (3) a displacing liquid stage of acid fracturing construction: the displacement liquid is active water, and the using amount of the displacement liquid is 1.1 times of the volume of the construction squeeze-injection pipe column.
The adhesive comprises a linear adhesive and a bonding agent, wherein the linear adhesive consists of the following components in percentage by weight: 0.3 wt% of hydroxypropyl guar gum, 0.2 wt% of bactericide, 0.2 wt% of cleanup additive and the balance of water. The apparent viscosity of the linear gel was 31mPa.s, pH 7.5.
The gelling acid consists of the following components, based on the total weight of the gelling acid: 18 wt% of hydrochloric acid with the mass concentration of 31%, 0.8 wt% of polymer gelling agent, 1 wt% of acidification corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water. The gelling acid has an apparent viscosity of 27.8 mpa.s; the acid-etched crack flow conductivity of the gelled acid is 38.6 mu m2.cm。
The occlusive acid consists of the following components in percentage by total weight of the occlusive acid: 20 wt% of hydrochloric acid with the mass concentration of 31%, 1 wt% of acidification corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water.
The displacement fluid consists of the following components (i.e., active water) by total weight: 0.2 wt% of discharge assistant agent and the balance of water.
Specific pump parameters are shown in table 2:
table 2 construction parameters of the acid fracturing method of example 2
| Serial number | Pumping stage | Discharge capacity m3/min | Volume m3 | Type of working fluid |
| 1 | Pretreatment liquid | 2 | 40 | Preparation ofLiquid medicine |
| 2 | Acid fracturing pad fluid | 4 | 70 | Linear glue |
| 3 | Acid fracturing working fluid | 4 | 60 | Gelled acid |
| 4 | Acid fracturing pad fluid | 4 | 60 | Linear glue |
| 5 | Acid fracturing working fluid | 4 | 50 | Gelled acid |
| 6 | Acid fracturing pad fluid | 4 | 40 | Linear glue |
| 7 | Acid fracturing working fluid | 4 | 40 | Gelled acid |
| 8 | Closed acid | 2 | 30 | Closed acid |
| 9 | Displacement replacement | 2 | 12.8 | Active water |
Example 3
The implementation provides an acid fracturing method for improving the yield of a geothermal well of a limestone reservoir, aiming at a GZXW-3 well, and the method comprises the following steps:
1. and selecting the geothermal production well to be subjected to acid fracturing modification based on the potential characteristics of the low-yield well and the reservoir characteristics of the low-yield well.
Wherein the potential characteristics are composed of the following characteristics (1) to (3):
(1) the linear well spacing between the geothermal production well and the water source reservoir body is 220 m;
(2) the geothermal production well and the water layer of the peripheral geothermal well have similar reservoir characteristics, and the adjacent well GZXW-3 has the water yield of 95m3/h；
(3) The sum of the lengths of the first and second fracture development intervals was 25 m.
The reservoir characteristics are composed of the following characteristics (1) to (3):
(1) the content of carbonate rock in the rock of the water producing layer is 96 percent; and the sum of the lengths of the first-class crack development layer and the second-class crack development layer is 25 mm;
(2) the temperature of a water producing layer is 58 ℃;
(3) the stress difference between the water producing layer and the upper interlayer and the stress difference between the water producing layer and the lower interlayer are both 3.5 MPa.
2. And (4) removing the drilling pollutants in the near wellbore zone by using a pretreatment fluid.
(1) Based on the total weight of the pretreatment liquid, the pretreatment liquid consists of the following components: 20 wt% of hydrochloric acid, 1 wt% of acidizing corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water.
(2) The dosage of the pretreatment liquid is calculated according to the treatment radius 3m of the acid fracturing layer section.
3. And carrying out acid fracturing construction to form artificial cracks so as to reform the water producing layer.
(1) The working fluid used for acid fracturing construction consists of pad fluid (linear glue), gelled acid, closed acid and displacement fluid.
(2) Acid fracturing stage of acid fracturing construction: the method comprises the following steps of sequentially forming a pre-liquid (linear gel) 1 stage, a working liquid (gelled acid) 1 stage, a pre-liquid (linear gel) 2 stage, a working liquid (gelled acid) 2 stage, a pre-liquid (linear gel) 3 stage and a working liquid (gelled acid) 3 stage, wherein the volume ratio of liquid pumping quantities of the pre-liquid 1 stage, the pre-liquid 2 stage and the pre-liquid 3 stage is 5.5: 5: 3; the volume ratio of the liquid pumping amount of the gelled acid 1 stage, the gelled acid 2 stage and the gelled acid 3 stage is 4.5: 4: 3.
(3) and (3) a closed acidification stage of acid fracturing construction: the closed acid is squeezed into the stratum under the stratum closed pressure, and the dosage is 5m of fracture volume of the near wellbore of the stratum.
(4) And (3) a displacing liquid stage of acid fracturing construction: the displacement liquid is active water, and the using amount of the displacement liquid is 1.1 times of the volume of the construction squeeze-injection pipe column.
The adhesive comprises a linear adhesive and a bonding agent, wherein the linear adhesive consists of the following components in percentage by weight: 0.3 wt% of hydroxypropyl guar gum, 0.2 wt% of bactericide, 0.2 wt% of cleanup additive and the balance of water. The apparent viscosity of the linear gel was 30mPa.s, pH 7.5.
The gelling acid consists of the following components, based on the total weight of the gelling acid: 18 wt% of hydrochloric acid with the mass concentration of 31%, 0.8 wt% of polymer gelling agent, 1 wt% of acidification corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water. The gelling acid has an apparent viscosity of 27 mpa.s; the acid-etched crack flow conductivity of the gelled acid is 39 mu m2.cm。
The occlusive acid consists of the following components in percentage by total weight of the occlusive acid: 20 wt% of hydrochloric acid with the mass concentration of 31%, 1 wt% of acidification corrosion inhibitor, 1 wt% of iron ion stabilizer, 0.2 wt% of cleanup additive and the balance of water.
The displacement fluid consists of the following components (i.e., active water) by total weight: 0.2 wt% of discharge assistant agent and the balance of water.
Specific pump parameters are shown in table 3:
table 3 construction parameters of the acid fracturing method of example 3
The effect of the above examples is evaluated as follows:
TABLE 4 Single well Effect comparison Table after implementation of the method according to the above example
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.
Claims (10)
1. An acid fracturing method for improving water yield of a limestone reservoir geothermal well is characterized by comprising the following steps of:
(1) pretreating the stratum by using pretreatment liquid;
(2) carrying out acid fracturing construction to form artificial cracks so as to modify a water producing layer; the acid fracturing construction comprises alternately injecting linear glue and gelled acid, then injecting closed acid, and finally injecting a displacement fluid.
2. The acid fracturing method according to claim 1, wherein the method further comprises the following steps before the step (1): and selecting the geothermal production well to be subjected to acid fracturing modification based on the potential characteristics of the low-yield well and the reservoir characteristics of the low-yield well.
3. The acid fracturing method according to claim 2, wherein the potential characteristics consist of the following characteristics (1) to (3):
(1) the linear well distance between the geothermal production well and the water source reservoir body is less than 300 m;
(2) the geothermal production well and the water layer of the peripheral geothermal well have similar reservoir characteristics, and the water yield of the adjacent well is more than 60m3/h；
(3) The sum of the lengths of the first-type and second-type fracture development intervals is more than 10 m.
4. The acid fracturing method of claim 2, wherein the reservoir characteristics consist of the following (1) - (3):
(1) the content of carbonate rock in the rock of the water producing layer is more than 80 percent; and the sum of the lengths of the first-class and second-class fracture development intervals is more than 10 m;
(2) the temperature of the water producing layer is 50-90 ℃;
(3) the stress difference between the water producing layer and the upper interlayer and the stress difference between the water producing layer and the lower interlayer are both 3-5 MPa.
5. The acid fracturing method of claim 1, wherein the pretreating the subterranean formation with the pretreatment fluid removes near wellbore drilling contaminants with the pretreatment fluid.
6. The acid fracturing method of claim 1, wherein the alternately injecting linear gum and gelled acid is a three-stage alternately injecting linear gum and gelled acid; the three-stage alternate injection of the linear glue and the gelled acid is sequentially injection of the linear glue, the gelled acid, the linear glue and the gelled acid.
7. The acid fracturing method of claim 6, wherein the injection volume ratio of the linear glue injected alternately in three stages is (5-7): (4-6): (3-4);
the injection volume ratio of the gelled acid injected alternately in three stages is (4-6) to (3-5) to (3-4).
8. The acid fracturing method of claim 1, wherein the displacement of the pre-treatment fluid is injected in the range of 2.0-2.5m3Min, the discharge capacity of injected linear glue is 3.5-4.0m3Min, the discharge capacity of the injected gelled acid is 3.5-4.0m3Min, the discharge of injected closed acid is 2.0-2.5m3Min, displacement of the injected displacement liquid is 2.0-2.5m3/min。
9. The acid fracturing method of claim 1, wherein the pretreatment fluid comprises, based on the total weight of the pretreatment fluid: 18-25 wt% of hydrochloric acid, 0.7-1.5 wt% of acidizing corrosion inhibitor, 0.7-1.5 wt% of iron ion stabilizer, 0.1-0.3 wt% of cleanup additive and the balance of water;
based on the total weight of the linear glue, the linear glue comprises 0.3-0.5 wt% of hydroxypropyl guar gum, 0.1-0.2 wt% of bactericide, 0.1-0.3 wt% of cleanup additive and the balance of water;
the gelling acid comprises, based on the total weight of the gelling acid: 15-20 wt% of hydrochloric acid, 0.7-0.9 wt% of polymer gelling agent, 1-2 wt% of acidizing corrosion inhibitor, 1-2 wt% of iron ion stabilizer, 0.2-0.3 wt% of cleanup additive and the balance of water;
the occlusive acid comprises, based on total weight of the occlusive acid: 16-20 wt% of hydrochloric acid, 1-2 wt% of acidizing corrosion inhibitor, 1-2 wt% of iron ion stabilizer, 0.2-0.3 wt% of cleanup additive and the balance of water;
the displacement fluid comprises, based on the total weight of the displacement fluid: 0.2 to 0.3 weight percent of discharge assistant and the balance of water.
10. The acid fracturing method of claim 1, wherein the linear gum has an apparent viscosity of 27-55mpa.s, a pH of 7-8;
the apparent viscosity of the gelled acid is 25-28 mPa.s; the acid-etched crack flow conductivity of the gelled acid is 35-40 mu m2.cm。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911108732.1A CN112796728A (en) | 2019-11-13 | 2019-11-13 | Acid fracturing method for improving water yield of limestone reservoir geothermal well |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911108732.1A CN112796728A (en) | 2019-11-13 | 2019-11-13 | Acid fracturing method for improving water yield of limestone reservoir geothermal well |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112796728A true CN112796728A (en) | 2021-05-14 |
Family
ID=75804003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911108732.1A Pending CN112796728A (en) | 2019-11-13 | 2019-11-13 | Acid fracturing method for improving water yield of limestone reservoir geothermal well |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112796728A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114439450A (en) * | 2022-01-12 | 2022-05-06 | 中国地质科学院水文地质环境地质研究所 | Acid fracturing production increasing process for deep geothermal water reservoir of carbonate rock |
| CN115288656A (en) * | 2022-06-30 | 2022-11-04 | 西南石油大学 | Complex phase acid deep acid fracturing method for deep ultra-deep high-temperature carbonate rock reservoir |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4807703A (en) * | 1987-08-19 | 1989-02-28 | Mobil Oil Corporation | Fracture acidizing sandstone formations |
| CN104564002A (en) * | 2014-12-16 | 2015-04-29 | 中国石油化工股份有限公司 | Pumping stop sand setting fracture-height-controlling acid fracturing process method applicable to carbonate reservoir |
| CN105089602A (en) * | 2015-06-18 | 2015-11-25 | 中国石油化工股份有限公司 | Variant-hydrochloric-acid-concentration acid fracturing method for carbonate reservoir |
| CN107965306A (en) * | 2016-10-20 | 2018-04-27 | 中国石油化工股份有限公司 | A kind of acid filling fracturing process |
| CN110318725A (en) * | 2019-06-28 | 2019-10-11 | 中石化石油工程技术服务有限公司 | A kind of remodeling method of geothermal reservoir |
-
2019
- 2019-11-13 CN CN201911108732.1A patent/CN112796728A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4807703A (en) * | 1987-08-19 | 1989-02-28 | Mobil Oil Corporation | Fracture acidizing sandstone formations |
| CN104564002A (en) * | 2014-12-16 | 2015-04-29 | 中国石油化工股份有限公司 | Pumping stop sand setting fracture-height-controlling acid fracturing process method applicable to carbonate reservoir |
| CN105089602A (en) * | 2015-06-18 | 2015-11-25 | 中国石油化工股份有限公司 | Variant-hydrochloric-acid-concentration acid fracturing method for carbonate reservoir |
| CN107965306A (en) * | 2016-10-20 | 2018-04-27 | 中国石油化工股份有限公司 | A kind of acid filling fracturing process |
| CN110318725A (en) * | 2019-06-28 | 2019-10-11 | 中石化石油工程技术服务有限公司 | A kind of remodeling method of geothermal reservoir |
Non-Patent Citations (1)
| Title |
|---|
| 王登轮等: "川东北海相气藏污水回注层深穿透酸压工艺技术及应用", 《内蒙古石油化工》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114439450A (en) * | 2022-01-12 | 2022-05-06 | 中国地质科学院水文地质环境地质研究所 | Acid fracturing production increasing process for deep geothermal water reservoir of carbonate rock |
| CN114439450B (en) * | 2022-01-12 | 2024-05-14 | 中国地质科学院水文地质环境地质研究所 | Acid fracturing yield increasing technology for carbonate deep geothermal water reservoir |
| CN115288656A (en) * | 2022-06-30 | 2022-11-04 | 西南石油大学 | Complex phase acid deep acid fracturing method for deep ultra-deep high-temperature carbonate rock reservoir |
| CN115288656B (en) * | 2022-06-30 | 2023-05-09 | 西南石油大学 | Deep ultra-deep high-temperature carbonate reservoir complex acid deep acid fracturing method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101353958B (en) | Acid fracturing process of oil gas well mining temperature control various mucic acid | |
| CN107255027B (en) | Compound modification method for carbonate rock reservoir | |
| CN105952430B (en) | A kind of compact oil reservoir low yield horizontal well volume fracturing supplement ENERGY METHOD | |
| CN106567702A (en) | Method for improving complexity index of deep shale gas fracture | |
| CN104963672B (en) | A kind of diverting material that cleans blocks up the reservoir reconstruction method of borehole formation seam net temporarily | |
| CN110388199B (en) | Large-discharge-capacity composite acid fracturing modification method for carbonate reservoir | |
| CN105089600B (en) | The method that temporarily stifled diverting material auxiliary water horizontal well carries out drawing type water-jet transformation | |
| CN100549126C (en) | Preposition acid solution and preposition sour sandfrac method | |
| US11136865B2 (en) | Integrated construction method of fracturing and tertiary oil recovery for low-permeability reservoir | |
| CN105317417A (en) | Fracturing method of medium-to-high-rank coal bed gas reservoir | |
| CN106437642A (en) | Fractured reservoir horizontal well injection-production asynchronous exploitation method | |
| CN112796728A (en) | Acid fracturing method for improving water yield of limestone reservoir geothermal well | |
| CN106958438B (en) | A kind of method for removing blockage of polymer flooding blocking well | |
| CN110318725B (en) | Method for improving geothermal reservoir | |
| CN105178910A (en) | Water-plugging process tubing string and method of horizontal wells | |
| CN108547607B (en) | Wide-band acidizing seam-making method for low-yield well of low-permeability oil field | |
| CN107246257B (en) | Heterogeneous reservoir is acidified remodeling method | |
| CN101942983A (en) | Process for performing well completion by utilizing biological completion fluid | |
| CN106150400A (en) | A kind of halogen mining well sleeve pipe curing means and method | |
| CN108643876A (en) | A kind of multidimensional pipe fracturing process for low-permeability oilfield stripper well | |
| CN113530511B (en) | Method for developing natural gas reservoir | |
| CN110272725B (en) | Acid-soluble plugging agent for staged fracturing of sidetracking slim hole and preparation method thereof | |
| US11041112B2 (en) | Breaker systems for wellbore treatment operations for use at varying temperatures | |
| CN112877046A (en) | Deep thickened oil blocking remover for oil well as preparation method and use method thereof | |
| CN112814641A (en) | Fracturing method of reservoir |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210514 |