CN112922573B - Fracturing method for compact oil reservoir horizontal well - Google Patents
Fracturing method for compact oil reservoir horizontal well Download PDFInfo
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- CN112922573B CN112922573B CN201911240694.5A CN201911240694A CN112922573B CN 112922573 B CN112922573 B CN 112922573B CN 201911240694 A CN201911240694 A CN 201911240694A CN 112922573 B CN112922573 B CN 112922573B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/62—Compositions for forming crevices or fractures
- C09K8/66—Compositions based on water or polar solvents
- C09K8/68—Compositions based on water or polar solvents containing organic compounds
- C09K8/685—Compositions based on water or polar solvents containing organic compounds containing cross-linking agents
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- 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
- C09K8/80—Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/84—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
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
Abstract
The invention provides a fracturing method of a compact oil reservoir horizontal well, which comprises the steps of injecting liquid nitrogen into the well; injecting a pre-fracturing fluid into the well; alternately injecting multi-effect slickwater fracturing fluid containing proppant and multi-effect guanidine gum fracturing fluid containing proppant; or injecting the multi-effect slickwater fracturing fluid containing the proppant into the well after alternately injecting the multi-effect slickwater fracturing fluid containing the proppant into the well. According to the invention, by injecting liquid nitrogen into the well and utilizing the gasification expansion of the liquid nitrogen due to pressure reduction and temperature rise after the liquid nitrogen enters the reservoir, the energy of a compact reservoir can be quickly supplemented, and the problems of quick pressure drop and short measure validity period after fracturing modification are avoided; in addition, the multi-effect slickwater fracturing fluid and the multi-effect guanidine gum fracturing fluid both contain a surfactant, and the interface performance of a porous medium of a reservoir can be improved, so that the adsorption energy of crude oil on a rock interface is greatly reduced, an oil film can be stripped, the migration resistance of the stripped oil film and oil drops on the porous medium is reduced, and the oil quantity is increased after the pressure is increased.
Description
Technical Field
The invention relates to the technical field of oil extraction in oil and gas field development, in particular to a fracturing method for a compact reservoir horizontal well.
Background
Fracturing is a method of using hydraulic action to create fractures in oil reservoirs for the purpose of enhanced oil and gas recovery.
In the prior art, a fracturing method is based on the principle of liquid pressure transmission, a high-pressure large-displacement pump is adopted on the ground, fracturing fluid with certain viscosity is injected into an oil layer at a pressure higher than the absorption capacity of the oil layer, the pressure in a shaft is gradually increased, so that high pressure is suppressed out at the bottom of a well, and when the pressure at the bottom of the well is higher than the stress near the wall of the well and the tensile strength of stratum rocks, a crack with certain geometric dimension and high flow conductivity is formed in the stratum near the bottom of the well, so that the purpose of improving the yield of an oil well is achieved.
However, the fracturing method has the defects of quick pressure drop, short effective period of measures, less accumulated oil increment and low extraction degree after being applied to fracturing transformation of a compact oil reservoir.
Disclosure of Invention
The invention provides a fracturing method for a horizontal well with a compact oil reservoir, which aims to solve the technical problems of high pressure drop, short oil extraction operation time and low oil extraction amount after fracturing modification in the prior art.
The invention provides a fracturing method for a compact oil reservoir horizontal well, which comprises the following steps:
liquid nitrogen is injected into the well.
And injecting a pre-fracturing fluid into the well.
Alternately injecting a multi-effect slickwater fracturing fluid containing a propping agent and a multi-effect guanidine gum fracturing fluid containing the propping agent into the well; or alternatively injecting the multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid containing the proppant into the well alternately, and then continuously injecting the multi-effect guanidine gum fracturing fluid containing the proppant into the well.
The fracturing method of the tight reservoir horizontal well comprises the following steps of: passing through a pump truck at a speed of 0.2-0.7m3Permin displacement 10-20m into the well3Of (2) liquid nitrogen.
The fracturing method of the tight reservoir horizontal well comprises the steps of injecting a multi-effect slickwater fracturing fluid containing a propping agent and a multi-effect guanidine gum fracturing fluid containing the propping agent into the well alternately; or, after the steps of alternately injecting the multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid containing the proppant into the well, and then injecting the multi-effect guanidine gum fracturing fluid containing the proppant into the well for multiple times, the method further comprises the following steps: and injecting a displacing fluid into the well so as to press all the pre-fracturing fluid, the multi-effect slickwater fracturing fluid containing the propping agent and the multi-effect guanidine gum fracturing fluid containing the propping agent into the cracks of the horizontal well.
The method for fracturing the tight reservoir horizontal well further comprises the following steps after the step of injecting the displacing fluid into the well: closing the well mouth valve to blank the well, and performing open flow and flowback after the pressure in the well is stable.
The fracturing method of the tight reservoir horizontal well comprises the steps that the pre-fracturing fluid accounts for 1/3-1/2 of the total liquid amount, wherein the total liquid amount is equal to the sum of the mass of the pre-fracturing fluid, the mass of the liquid nitrogen, the mass of the multi-effect slickwater fracturing fluid containing the propping agent, the mass of the multi-effect guanidine gum fracturing fluid containing the propping agent and the mass of the displacing fluid.
The fracturing method of the compact reservoir horizontal well comprises the following steps of (1) preparing a fracturing fluid, wherein the fracturing fluid is a multi-effect slickwater fracturing fluid which comprises the following components in parts by weight: 0.05-0.1 part of drag reducer, 0.4-0.6 part of nonionic fatty alcohol-polyoxyethylene ether, 0.8-1.0 part of anionic fatty alcohol sulfonate and the balance of water.
The fracturing method of the tight reservoir horizontal well comprises the following steps of: 0.2 part of thickening agent, 0.5-1.0 part of clay stabilizer, 0.05 part of bactericide, 0.04-0.06 part of nonionic fatty alcohol-polyoxyethylene ether, 0.08-0.1 part of anionic fatty alcohol sulfonate, 0.3 part of cleanup additive, 0.25-0.35 part of cross-linking agent, and the balance of water and alkaline pH conditioning agent.
The fracturing method of the tight reservoir horizontal well as described above, wherein the proppant: the multi-effect slickwater fracturing fluid = 1; the proppant is: the multi-effect guanidine gum fracturing fluid = 1.
The fracturing method of the tight reservoir horizontal well comprises the step of fracturing the tight reservoir horizontal well, wherein the proppant is a mixture of 70-140 meshes of quartz sand and 40-70 meshes of quartz sand.
The fracturing method of the tight reservoir horizontal well comprises the following steps of (1) enabling quartz sand of 70-140 meshes to account for 60-80% of the total amount of a propping agent; the 40-70 mesh quartz sand accounts for 20-40% of the total amount of the proppant.
The invention provides a fracturing method for a compact oil reservoir horizontal well, which comprises the following steps: injecting liquid nitrogen into the well; after injecting the pre-fracturing fluid into the well, alternately injecting a multi-effect slickwater fracturing fluid containing a propping agent and a multi-effect guanidine gum fracturing fluid containing the propping agent; or alternatively, injecting the preposed fracturing fluid and the multi-effect slickwater fracturing fluid containing the proppant into the well alternately, then injecting the multi-effect guanidine gum fracturing fluid containing the proppant, and the like. According to the invention, liquid nitrogen is injected into the well, and is gasified due to reduced pressure and increased temperature after entering the reservoir stratum, so that the volume of the liquid nitrogen is expanded, the energy of the compact reservoir stratum can be rapidly supplemented, and the problems of rapid pressure drop and short measure validity period after fracturing modification are avoided; in addition, the multi-effect slickwater fracturing fluid and the multi-effect guanidine gum fracturing fluid both contain a surfactant, and the interface performance of a porous medium of a reservoir can be improved, so that the adsorption energy of crude oil on a rock interface is greatly reduced, an oil film can be stripped, the migration resistance of the stripped oil film and oil drops on the porous medium is reduced, and the oil quantity is increased after the pressure is increased.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the disclosure.
FIG. 1 is a schematic flow diagram of one embodiment of a tight reservoir horizontal well fracturing method provided by the present invention;
fig. 2 is a schematic flow diagram of another embodiment of the method for fracturing a tight reservoir horizontal well according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.
The embodiments and features of the embodiments of the present invention may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
FIG. 1 is a schematic flow diagram of one embodiment of a tight reservoir horizontal well fracturing method provided by the present invention; fig. 2 is a schematic flow diagram of another embodiment of the method for fracturing a tight reservoir horizontal well according to the present invention.
Referring to fig. 1 and fig. 2, an embodiment of the present invention provides a method for fracturing a tight reservoir horizontal well, including:
s101: liquid nitrogen is injected into the well.
S102: and injecting a pre-fracturing fluid into the well.
S103: alternately injecting multi-effect slickwater fracturing fluid containing proppant and multi-effect guanidine gum fracturing fluid containing proppant; or injecting the multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid containing the proppant into the well alternately, and then injecting the multi-effect guanidine gum fracturing fluid containing the proppant for multiple times.
Specifically, the fracturing method of the tight reservoir horizontal well can be used in the technical field of oil extraction in oil and gas field development, wherein two implementation schemes can be provided after the step of injecting the pre-fracturing fluid into the well, wherein the implementation scheme comprises the following steps: alternately injecting a multi-effect slickwater fracturing fluid containing a propping agent and a multi-effect guanidine gum fracturing fluid containing the propping agent into the well; and secondly, injecting the multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid containing the proppant into the well alternately, and then injecting the multi-effect guanidine gum fracturing fluid containing the proppant into the well.
This example will be described by taking as an example the alternate injection into a well of a multi-effect slickwater fracturing fluid containing a proppant and a multi-effect guanidine gum fracturing fluid containing a proppant.
Before a tight reservoir horizontal well fracturing method is implemented on a reservoir, fracturing equipment needs to be prepared and debugged according to site construction conditions, wherein the fracturing equipment can comprise a pump truck, an instrument truck, a sand mixing truck, a sand tank and the like.
After the fracturing equipment is prepared completely, a certain amount of liquid nitrogen is injected into the well, the amount of the injected liquid nitrogen can be determined according to the predicted liquid production amount of the well, the energy of a compact reservoir can be supplemented by injecting the liquid nitrogen, and the problems of high pressure drop and short measure validity period after fracturing modification are solved.
And then injecting a pre-fracturing fluid into the well, and then alternately injecting a multi-effect slickwater fracturing fluid containing a propping agent and a multi-effect guanidine gum fracturing fluid containing a propping agent into the well, wherein the pre-fracturing fluid aims at fracturing a target reservoir of the horizontal well to form cracks in the reservoir, and the multi-effect slickwater fracturing fluid containing the propping agent and the multi-effect guanidine gum fracturing fluid containing the propping agent are added to fix the cracks, so that the cracks are prevented from being closed after fracturing is completed, and the fracturing measures are not effective. In addition, the alternation times of the multi-effect slickwater fracturing fluid containing the proppant and the multi-effect guanidine gum fracturing fluid containing the proppant can be selected according to the specific situation of designing the total fluid quantity and the sand adding strength, and preferably, the alternation times is seven times.
It can be understood that in order to facilitate the smooth injection of the liquid nitrogen, the pre-fracturing fluid, the multi-effect slickwater fracturing fluid containing the proppant and the multi-effect guanidine gum fracturing fluid containing the proppant into the well, the casing can be lowered to a preset position in the horizontal well, and the substances can be injected into the well through the casing, so that the construction smoothness is ensured.
The embodiment of the invention provides a fracturing method for a compact oil reservoir horizontal well, which comprises the following steps: injecting liquid nitrogen into the well; injecting a pre-fracturing fluid into the well; and then alternately injecting multi-effect slickwater fracturing fluid containing proppant and multi-effect guanidine gum fracturing fluid containing proppant, or injecting multi-effect slickwater fracturing fluid containing proppant for multiple times after alternately injecting the multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid containing proppant into the well. According to the invention, liquid nitrogen is injected into the well, and is gasified due to reduced pressure after entering the reservoir, so that the energy of the compact reservoir can be quickly supplemented, and the problems of quick pressure drop and short measure validity period after fracturing modification are avoided; in addition, the multi-effect slickwater fracturing fluid and the multi-effect guanidine gum fracturing fluid both contain multi-effect surfactants, and the interface performance of a reservoir porous medium can be improved, so that the adsorption energy of crude oil on a rock interface is greatly reduced, an oil film can be stripped, the migration resistance of the stripped oil film and oil drops on the porous medium is reduced, and the oil quantity is increased after the pressure is increased.
As an implementable manner, S101 can also be implemented according to the following manner:
according to the liquid extraction amount of the horizontal well, the oil is pumped by a pump truck at the speed of 0.2-0.7m3Injecting 10-20m into the well with a/min discharge capacity3Of (2) liquid nitrogen. In the embodiment, enough nitrogen is provided in the well by controlling the adding speed and the adding amount of the liquid nitrogen, the pressure in the well is increased, the problems of high pressure drop and short effective period of measures after fracturing is finished are avoided, and preferably, the pressure is controlled to be 0.5m by a pump truck3Permin displacement for injecting 15m into well3Of (2) liquid nitrogen.
As an alternative embodiment of the step S103, after injecting the pre-fracturing fluid into the well, the multi-effect slickwater fracturing fluid containing the proppant and the multi-effect guanidine gum fracturing fluid containing the proppant are alternately injected.
Specifically, firstly, injecting a preposed fracturing fluid into a well to press out fractures in a reservoir, and creating new fractures through fracturing to increase the oil drainage area; and then, by alternately injecting a multi-effect slickwater fracturing fluid containing a propping agent and a multi-effect guanidine gum fracturing fluid containing the propping agent, the fracture is fixed to the maximum extent, and the extraction rate is increased.
Further, after S103, the method may further include: and (5) injecting a displacing fluid into the well, so that the pre-fracturing fluid, the multi-effect slickwater fracturing fluid containing the propping agent and the multi-effect guanidine gum fracturing fluid containing the propping agent in the well are all pressed into the cracks of the horizontal well, and marking as S104.
Specifically, the displacement fluid can be injected to completely displace the pre-fracturing fluid, the multi-effect slickwater fracturing fluid containing the propping agent and the multi-effect guanidine gum fracturing fluid containing the propping agent into the cracks, so that sand blocking in the shaft is avoided.
As a preferred embodiment of the displacement fluid, the displacement fluid is slickwater, wherein the displacement fluid is added in an amount of 1-1.2 times the wellbore volume in the well.
Specifically, slickwater is used as a displacement fluid, so that the pre-fracturing fluid, the multi-effect slickwater fracturing fluid containing the proppant and the multi-effect guanidine gum fracturing fluid containing the proppant can be completely displaced into the cracks, and sand blocking in a shaft is avoided. As for the displacement fluid, it may be added in an amount of 1-1.2 times the volume of the wellbore in the well, preferably, it may be added in an amount of 1.1 times the volume of the wellbore in the well.
Further, after the displacement fluid is injected into the well, the method further comprises the following steps: closing a well mouth valve to carry out well closing, and carrying out open flow and flowback after the pressure in the well is stable, and marking as S105.
And particularly, after the fracturing construction is finished, stopping a pump, closing a wellhead valve, and adopting a post-fracturing stuffy well to fully diffuse pressure. And when the pressure of the well head is reduced to be less than 0.01MPa within the preset time, performing open flow and flowback, wherein the preset time can be limited according to actual construction, for example, the preset time is 3-5 days.
In the embodiment, the injected multiple-effect slickwater fracturing fluid and the multiple-effect guanidine gum fracturing fluid are fully acted with the surface of the reservoir rock and fully replaced with the reservoir crude oil through closing and closing the well after fracturing, so that the effect of further improving the recovery ratio is achieved. In addition, the multi-effect surfactant in the multi-effect slickwater fracturing fluid and the multi-effect guanidine gum fracturing fluid can prevent compact pores and micro-crack water lock, reduce the oil-water emulsification rate and improve the fluidity of reservoir crude oil. Moreover, the multi-effect surfactant can change the wettability of the reservoir core from neutral weak lipophilicity to neutral weak hydrophilicity, so that the recovery rate of the permeability of the fractured core reaches 96 percent.
As a preferred embodiment of the injection amount of the pre-fracturing fluid, the pre-fracturing fluid accounts for 1/3-1/2 of the total amount of the pre-fracturing fluid, wherein the total amount of the pre-fracturing fluid is equal to the sum of the mass of the pre-fracturing fluid, liquid nitrogen, the multi-effect slickwater fracturing fluid containing the propping agent, the multi-effect guanidine gum fracturing fluid containing the propping agent and the displacing fluid.
Specifically, the addition amount of the pre-fracturing fluid can be designed according to the total amount of the fracturing fluid injected into the well, and the total amount of the fracturing fluid is calculated by numerical simulation software according to the reservoir reconstruction volume and the length of the fracture, for example, in the actual production operation, the longer the length of the horizontal well section is, the larger the total fluid amount is, and vice versa. Preferably, the addition amount of the pre-fracturing fluid accounts for 1/2 of the total fluid amount.
Further, the preposed fracturing fluid is a multi-effect slickwater fracturing fluid which comprises the following components in parts by weight: 0.05-0.1 part of drag reducer, 0.4-0.6 part of nonionic fatty alcohol-polyoxyethylene ether, 0.8-1.0 part of anionic fatty alcohol sulfonate and the balance of water.
Specifically, the multi-effect slickwater fracturing fluid is used as a low-viscosity fluid, can be pumped and injected in a large-displacement and large-scale manner, can quickly open a compact reservoir to form a crack, and can improve the drainage volume of the compact reservoir, wherein the content of each component in the multi-effect slickwater is calculated by weight parts, which represents the proportion of each component, and the total weight parts can be 100 parts or 10 parts, and the embodiment is not specifically limited herein. According to the embodiment, the interface performance of the porous medium of the reservoir can be improved by adding the nonionic fatty alcohol-polyoxyethylene ether and the anionic fatty alcohol sulfonate, so that the adsorption energy of crude oil on a rock interface is greatly reduced, an oil film can be stripped better, the migration resistance of the stripped oil film and oil drops on the porous medium is reduced, and the fluidity and the recovery ratio of the crude oil are increased.
Further, the multi-effect guanidine gum fracturing fluid comprises the following components in parts by weight: 0.2 part of thickening agent, 0.5-1.0 part of clay stabilizer, 0.05 part of bactericide, 0.04-0.06 part of nonionic fatty alcohol polyoxyethylene ether, 0.08-0.1 part of anionic fatty alcohol sulfonate, 0.3 part of cleanup additive, 0.25-0.35 part of cross-linking agent, and the balance of water and alkaline pH conditioner; proppant: multi-effect slickwater fracturing fluid = 1; proppant: the multi-effect guanidine gum fracturing fluid = 1.
Specifically, the multi-effect guanidine gum fracturing fluid is used as a high-viscosity liquid, can well carry sand into a compact reservoir, and can prevent a fracture from closing after fracturing, so that the permeability of the reservoir is improved, and the flow conductivity is increased, wherein the content of each component in the multi-effect slickwater is calculated by weight, which represents the proportion of each component, and the total weight of the components is 100 parts or 10 parts, and the embodiment is not specifically limited herein.
In addition, the clay stabilizer used in the present embodiment may be potassium chloride; the discharge assistant can be a fluorocarbon surfactant; the alkaline PH conditioner may be sodium carbonate for adjusting the PH of the multi-effect guargum fracturing fluid to a PH between 8 and 11, the amount of alkaline PH conditioner may be determined according to the depth of the well, the deeper the well, the higher the PH, and the lower the PH, for example: the well depth is 1500-2000m, the PH value is adjusted to 8-9, the well depth is 2000-3000m, the PH value is adjusted to 9-10, the well depth is 3000-4000m, and the PH value is adjusted to 10-11.
Further, proppant: the multi-effect slickwater fracturing fluid = 1; proppant: multi-effect guanidine gum fracturing fluid = 1; and the proppant is a mixture of 70-140 mesh quartz sand and 40-70 mesh quartz sand.
Specifically, the proppant is used for improving the flow conductivity of the fracture and prolonging the propping time of the fracture, wherein the proportion of the proppant to the multi-effect slickwater fracturing fluid and the proportion of the proppant to the multi-effect guanidine gum fracturing fluid can be adjusted according to the length of a horizontal well section and the fracture scale required by design, such as: the horizontal well section is long, the fracture scale is large, and the addition amount of the proppant can be increased in a proper amount, and vice versa. Preferably, during the actual fracturing process, the proppant: the proportion of the multi-effect slickwater fracturing fluid and the proppant are as follows: the proportions of the multi-effect guanidine gum fracturing fluid are all prepared according to the ratio of 1.
In addition, the propping agent can be a mixture of 70-140 mesh quartz sand and 40-70 mesh quartz sand, wherein the 70-140 mesh quartz sand can account for 60% -80% of the propping agent, and the purpose is to firstly prop a fine fracture system by using the 70-140 mesh quartz sand propping agent and then carry out chasing by using the 40-70 mesh quartz sand propping agent so as to improve the fracture conductivity and prolong the fracture propping time.
Illustratively, the specific operation steps of the above method embodiment are as follows:
step 1: and (5) after all links of the fracturing construction are checked to meet quality safety regulations, beginning formal construction according to on-site command instructions.
Step 2: and (5) testing the pressure of ground equipment. The pressure test of the pump truck is 90MPa, the pressure is stabilized for 5min, the pressure drop is less than the standard specification, and each link on the ground normally works as a qualified link; wherein, the construction pressure limit is 60-85MPa, and when the pressure distance is limited to 3-10MPa, measures are taken to prevent the pressure from exceeding the pressure limit.
And step 3: injecting preposed liquid nitrogen into the well at the speed of 0.5m3The pump injection volume of/min injects liquid nitrogen by 10-20m3。
And 4, step 4: and performing second-stage pre-fracturing construction. At 8-10m3The pump injection displacement of/min is injected into the multi-effect slickwater fracturing fluid with the volume of 200-600m3。
And 5: and performing second-stage fracturing construction. At 8-14m3Injecting multiple-effect slickwater fracturing fluid containing 3% of propping agent into fracturing fluid with the pump injection displacement of/min for 20-30m3。
And 6: and carrying out third-stage fracturing construction. At 8-14m3Injecting multi-effect guanidine gum fracturing fluid containing 3% of proppant 40-50m at a pump injection displacement of/min3。
And 7: and repeating the fifth step and the sixth step for 3-7 times according to the amount of the fracturing fluid and the amount of the propping agent until the fracturing fluid and the propping agent which are reserved according to the design are used up.
And step 9: injecting slick water as displacing liquid in 20-60m3The displacement liquid is prepared according to 1-1.2 times of the volume of the well bore.
Step 10: and stopping the pump after the fracturing construction is finished, closing a wellhead valve, and fully diffusing the pressure by adopting a post-fracturing well closing mode.
Step 11: the construction pipeline is disassembled, the valve is poured, and when the pressure at the well head (the pressure drop is less than 0.01 MPa) is stable, the open flow and the return flow are implemented.
The above method is described in detail below using specific embodiments:
step 1: and after each link of fracturing construction is checked to meet quality safety regulations, formal construction is started according to on-site command instructions.
And 2, testing the pressure by ground equipment. The pressure test of the pump truck is 90MPa, the pressure is stabilized for 5min, the pressure drop is less than the standard specification, and each link on the ground normally works to be qualified.
And step 3: at 0.5-1m3Permin pump injection liquid nitrogen injection 20m3。
And 4, step 4: and performing the first stage of fracturing construction. At 8-12m3Permin pump injection displacement injection multi-effect slickwater fracturing fluid 600m3。
And 5: and performing second-stage fracturing construction. At 8-12m3Injecting multiple-effect slickwater fracturing fluid containing proppant 30m into per minute of pump injection displacement3。
Step 6: and performing third-stage fracturing construction. At 8-12m3Injecting multi-effect guanidine gum fracturing fluid containing proppant 50m into the fracturing fluid by the pump injection displacement of/min3。
And 7: table 1 shows a fracturing pump injection procedure (i), and table 1 defines the addition amounts and the addition sequence of liquid nitrogen, a pre-fracturing fluid, a multi-effect slickwater fracturing fluid containing a proppant, a multi-effect guar gum fracturing fluid containing a proppant and a displacing fluid used in a fracturing method of a tight reservoir horizontal well. And (3) repeating the step 5 and the step 6 according to the procedure listed in the fracturing pump injection procedure (I) in the table 1, and alternately injecting the proppant-containing multi-effect slickwater and the proppant-containing multi-effect guanidine gum fracturing fluid for 7 times.
And 8: at 8-12m3Permin pump injection capacity injection 40m3And stopping the pump after the slickwater replaces the liquid.
Table 1 fracturing pump injection procedure 1
And step 9: and stopping the pump after the fracturing construction is finished, closing a wellhead valve, and fully diffusing the pressure by adopting a post-fracturing well closing mode.
Step 10: and (4) detaching the construction pipeline, pouring the valve, and performing open flow and flowback after the pressure at the well head is stable.
As another embodiment of S103, please refer to fig. 2 for a specific process flow, specifically referring to the technical solution: and injecting a pre-fracturing fluid into the well, and then alternately injecting a multi-effect slickwater fracturing fluid and a multi-effect slickwater fracturing fluid containing a propping agent into the well, and then injecting a multi-effect guanidine gum fracturing fluid containing the propping agent. The remaining steps are the same as the above embodiments, and refer to the contents of the above embodiments specifically.
Specifically, in the embodiment, after the pre-fracturing fluid is injected into the well, the multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid containing the proppant are alternately injected, so that the reservoir can be quickly pressed open to form cracks, and the proppant carried in the multi-effect slickwater fracturing fluid can play a supporting role to prevent the cracks from being closed in the process of pressing open the reservoir, so that the difficulty of the fracturing process is increased; and finally, injecting a fracturing fluid containing a proppant multi-effect guanidine gum into the well, and further playing a role in fixing the fracture.
The above method is described in detail below using specific embodiments:
step 1: and after each link of fracturing construction is checked to meet quality safety regulations, formal construction is started according to on-site command instructions.
And 2, testing the pressure by ground equipment. The pressure test of the pump truck is 70MPa, the pressure is stabilized for 5min, the pressure drop is less than the standard specification, and the ground links work normally to be qualified.
And 3, step 3: at 0.5-1m3Permin pump injection liquid nitrogen injection 20m3。
And 4, step 4: and performing the first stage of fracturing construction. At 8-12m3Permin pump injection displacement injection multi-effect slickwater fracturing fluid 580m3。
And 5: and performing second-stage fracturing construction. According to the procedure listed in the fracturing pump injection procedure (II) of Table 2, at 8-12m3Permin pump injection volume is injected with multi-effect slickwater fracturing fluid containing proppant by 10m3。
Step 6: and carrying out third-stage fracturing construction. At 8-12m3Permin pump injection displacement is injected into multi-effect slickwater fracturing fluid for 30m3。
And 7: table 2 shows the fracturing pump injection procedure (ii), and table 2 defines the addition amounts and the addition sequence of the liquid nitrogen, the multi-effect slickwater fracturing fluid containing the proppant and the displacing fluid used in the fracturing method of the tight reservoir horizontal well. And (3) repeating the step 5 and the step 6 according to the procedures listed in the fracturing pump injection procedure (II) in the table 2, and alternately injecting the proppant-containing multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid for 5 times.
And step 8: the fracturing pump injection program (II) in the table 2 is carried out at 8-12m3Permin pump injection volume is injected into 7 sections of multi-effect guanidine gum fracturing fluid containing different proppant proportions by 20-80m3。
And step 9: at 8-12m3Permin pump injection capacity injection 40m3And stopping the pump after the slick water replaces the liquid.
TABLE 2 fracturing pump injection program (II)
Step 10: and stopping the pump after the fracturing construction is finished, closing a wellhead valve, and fully diffusing the pressure by adopting a post-fracturing well closing mode.
Step 11: and (4) removing the construction pipeline, pouring the valve, and performing open flow and flowback when the wellhead pressure (the pressure drop is less than 0.01 MPa) is stable.
In the description above, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (7)
1. A fracturing method for a tight reservoir horizontal well is characterized by comprising the following steps:
injecting liquid nitrogen into the well;
injecting a pre-fracturing fluid into the well after injecting liquid nitrogen into the well;
alternately injecting a multi-effect slickwater fracturing fluid containing a proppant and a multi-effect guanidine gum fracturing fluid containing a proppant into the well; or injecting multiple-effect slickwater fracturing fluid and multiple-effect slickwater fracturing fluid containing proppant into the well alternately, and then injecting multiple-effect guanidine gum fracturing fluid containing proppant into the well for multiple times;
the pre-fracturing fluid is a multi-effect slickwater fracturing fluid which comprises the following components in parts by weight: 0.05-0.1 part of drag reducer, 0.4-0.6 part of nonionic fatty alcohol-polyoxyethylene ether, 0.8-1.0 part of anionic fatty alcohol sulfonate and the balance of water;
the step of injecting liquid nitrogen into the well comprises: passing through a pump truck at a speed of 0.2-0.7m3Permin displacement 10-20m into the well3The liquid nitrogen of (2);
the multi-effect guanidine gum fracturing fluid comprises the following components in parts by weight: 0.2 part of thickening agent, 0.5-1.0 part of clay stabilizer, 0.05 part of bactericide, 0.04-0.06 part of nonionic fatty alcohol-polyoxyethylene ether, 0.08-0.1 part of anionic fatty alcohol sulfonate, 0.3 part of cleanup additive, 0.25-0.35 part of cross-linking agent, and the balance of water and alkaline pH conditioning agent.
2. The tight reservoir horizontal well fracturing method of claim 1, wherein a multi-effect slickwater fracturing fluid containing a proppant and a multi-effect guanidine gum fracturing fluid containing a proppant are alternately injected into the well; or, after the steps of alternately injecting the multi-effect slickwater fracturing fluid and the multi-effect slickwater fracturing fluid containing the proppant into the well and then injecting the multi-effect guanidine gum fracturing fluid containing the proppant into the well for multiple times, the method further comprises the following steps:
and injecting a displacing fluid into the well so as to press all the pre-fracturing fluid, the multi-effect slickwater fracturing fluid containing the proppant and the multi-effect guanidine gum fracturing fluid containing the proppant into the fracture of the horizontal well.
3. The tight reservoir horizontal well fracturing method of claim 2, further comprising, after the step of injecting a displacement fluid into the well: closing the well mouth valve to blank the well, and performing open flow and flowback after the pressure in the well is stable.
4. The tight reservoir horizontal well fracturing method of claim 3, wherein the pad fracturing fluid accounts for 1/3 to 1/2 of the total fluid volume, wherein the total fluid volume is equal to the sum of the mass of the pad fracturing fluid, the liquid nitrogen, the proppant-containing multi-effect slickwater fracturing fluid, the proppant-containing multi-effect guanidine gum fracturing fluid and the displacing fluid.
5. The tight reservoir horizontal well fracturing method of claim 1 wherein the proppant: the multi-effect slickwater fracturing fluid = 1; the proppant is characterized in that: the multi-effect guanidine gum fracturing fluid = 1.
6. The tight reservoir horizontal well fracturing method of claim 5 wherein the proppant is a mixture of 70-140 mesh quartz sand and 40-70 mesh quartz sand.
7. The tight reservoir horizontal well fracturing method of claim 6, wherein the quartz sand of 70-140 mesh accounts for 60% -80% of the total amount of proppant;
the 40-70 mesh quartz sand accounts for 20-40% of the total amount of the proppant.
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