CN111963130A - Fracturing method capable of maintaining flow conductivity of cracks for long time and application thereof - Google Patents
Fracturing method capable of maintaining flow conductivity of cracks for long time and application thereof Download PDFInfo
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- CN111963130A CN111963130A CN202010904044.2A CN202010904044A CN111963130A CN 111963130 A CN111963130 A CN 111963130A CN 202010904044 A CN202010904044 A CN 202010904044A CN 111963130 A CN111963130 A CN 111963130A
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- 239000003795 chemical substances by application Substances 0.000 claims abstract description 73
- 239000003112 inhibitor Substances 0.000 claims abstract description 66
- 230000002401 inhibitory effect Effects 0.000 claims abstract description 27
- 239000012530 fluid Substances 0.000 claims abstract description 26
- 238000002156 mixing Methods 0.000 claims abstract description 26
- 239000004576 sand Substances 0.000 claims abstract description 24
- 238000001556 precipitation Methods 0.000 claims abstract description 11
- 239000008187 granular material Substances 0.000 claims abstract description 10
- 239000012258 stirred mixture Substances 0.000 claims abstract description 8
- 238000003756 stirring Methods 0.000 claims abstract description 6
- 239000001993 wax Substances 0.000 claims description 92
- 239000002245 particle Substances 0.000 claims description 22
- 230000015572 biosynthetic process Effects 0.000 claims description 19
- 239000003129 oil well Substances 0.000 claims description 15
- MTNDZQHUAFNZQY-UHFFFAOYSA-N imidazoline Chemical compound C1CN=CN1 MTNDZQHUAFNZQY-UHFFFAOYSA-N 0.000 claims description 11
- 229940051841 polyoxyethylene ether Drugs 0.000 claims description 11
- 229920000056 polyoxyethylene ether Polymers 0.000 claims description 11
- BWYYYTVSBPRQCN-UHFFFAOYSA-M sodium;ethenesulfonate Chemical compound [Na+].[O-]S(=O)(=O)C=C BWYYYTVSBPRQCN-UHFFFAOYSA-M 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000007334 copolymerization reaction Methods 0.000 claims description 7
- 239000012188 paraffin wax Substances 0.000 claims description 7
- 238000007865 diluting Methods 0.000 claims description 5
- 230000007774 longterm Effects 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 239000002455 scale inhibitor Substances 0.000 claims description 3
- 230000005923 long-lasting effect Effects 0.000 claims 1
- 230000009467 reduction Effects 0.000 abstract description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 21
- 239000003921 oil Substances 0.000 description 11
- 239000000243 solution Substances 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 8
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- 230000008021 deposition Effects 0.000 description 4
- 239000008398 formation water Substances 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000003208 petroleum Substances 0.000 description 4
- 239000011435 rock Substances 0.000 description 4
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- 241001365958 Ceroplastes cirripediformis Species 0.000 description 1
- CHJJGSNFBQVOTG-UHFFFAOYSA-N N-methyl-guanidine Natural products CNC(N)=N CHJJGSNFBQVOTG-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—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
- C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
- C09K8/524—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning organic depositions, e.g. paraffins or asphaltenes
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- 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
- C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
- C09K8/536—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning characterised by their form or by the form of their components, e.g. encapsulated material
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B37/00—Methods or apparatus for cleaning boreholes or wells
- E21B37/06—Methods or apparatus for cleaning boreholes or wells using chemical means for preventing or limiting, e.g. eliminating, the deposition of paraffins or like substances
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
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- Mining & Mineral Resources (AREA)
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- General Life Sciences & Earth Sciences (AREA)
- Fluid Mechanics (AREA)
- Environmental & Geological Engineering (AREA)
- Geochemistry & Mineralogy (AREA)
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Abstract
The invention provides a fracturing method for long-acting maintaining of fracture conductivity and application thereof, wherein the fracturing method comprises the following steps: injecting a fracturing proppant into the sand mixing truck; injecting the scale-inhibiting and wax-preventing agent into a sand mixing truck; continuously stirring the fracturing propping agent and the scale and wax inhibitor in a sand mixing truck; and injecting the uniformly stirred mixture into the target stratum. After the scale and wax inhibitor is injected into a hydraulic fracture together with a fracturing propping agent, the granular scale and wax inhibitor is positioned between granule gaps of the fracturing propping agent, granules with two grain sizes jointly enter the hydraulic fracture of a target stratum, the fracturing propping agent is used for propping the hydraulic fracture, the scale and wax inhibitor contacts stratum fluid in the hydraulic fracture after entering the target stratum and is slowly dissolved into solution, and the released wax inhibiting and preventing component can effectively inhibit scaling and wax precipitation in the artificial fracture to the maximum extent, so that the artificial fracture keeps better flow conductivity for a long time, and the yield reduction caused by the reduction of the flow conductivity of the fracture due to scaling and wax precipitation is reduced.
Description
Technical Field
The invention belongs to the field of oil and gas field exploration and development, and particularly relates to a fracturing method capable of keeping the flow conductivity of a fracture for a long time and application thereof.
Background
The hydraulic fracturing is an effective technical means for improving the yield of a single well by a low-permeability compact oil reservoir, the fracture conductivity at the initial stage of the hydraulic fracturing is high, an oil well can produce according to normal yield, but scale formation, wax precipitation and crack blockage can gradually occur in an artificial fracture along with the extension of production time, the resistance of fluid flowing in the fracture is increased, and the fracture conductivity is reduced, so that the yield of the oil well is reduced, and even the oil well can completely lose productivity in severe cases.
In order to reduce the influence of scaling and wax precipitation on the oil well production performance, the currently adopted measures are to add agents for preventing scaling and wax precipitation into a well bore from a ground well head, but the method only can slow down the wax precipitation and the scale on the wall surface of the well bore and near the bottom of the well bore, and cannot act on the inside or even the far end of a crack.
Generally, after 2-3 years of operation of a common oil well, the flow conductivity of a crack is reduced by over 70% under the influence of wax and scale, and for an oil well with high formation water mineralization, the scaling speed is higher, and the yield is reduced to 1/3 which is less than the initial yield in about 1 year.
Disclosure of Invention
The embodiment of the invention aims to provide a fracturing method for keeping the flow conductivity of a crack for a long time and application thereof so as to overcome the technical defects.
In order to solve the technical problem, the invention provides a fracturing method for long-acting maintaining of fracture conductivity, which comprises the following steps:
injecting a fracturing proppant into the sand mixing truck;
injecting the scale-inhibiting and wax-preventing agent into a sand mixing truck;
continuously stirring the fracturing propping agent and the scale and wax inhibitor in a sand mixing truck;
and injecting the uniformly stirred mixture into the target stratum.
Further, the scale and wax inhibitor is prepared by copolymerizing the following components: sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline.
Further, the scale and wax inhibitor is prepared according to the following method:
taking sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline, carrying out copolymerization reaction according to the mass ratio of (0.5-0.8) to (0.8-1.1) to (0.7-1.0), and sequentially diluting, drying and evaporating the generated product to obtain the granular scale and wax inhibitor.
Preferably, the particle size of the granular scale and wax inhibitor is smaller than that of the fracturing propping agent, and the volume ratio of the fracturing propping agent to the scale and wax inhibitor is 58:1 when the granular scale and wax inhibitor and the fracturing propping agent are mixed.
The invention also provides an application of the fracturing method for long-acting maintaining of the fracture conductivity, which at least comprises the fracturing method for long-acting maintaining of the fracture conductivity, and the application is as follows:
selecting a hydraulically fractured oil well as a target well;
selecting a stratum with water conservancy fractures in a target well as a target stratum;
continuously injecting the uniformly stirred mixture of the fracturing propping agent and the scale and paraffin inhibitor into the target well by the sand mixing truck;
the scale and wax inhibitor enters hydraulic fractures of a target stratum together with the fracturing propping agent;
the granular scale and wax inhibitor is slowly dissolved into solution after meeting formation fluid in the hydraulic fracture;
the scale inhibitor and the wax inhibitor in the solution state are attached and contacted with each other and dissolve scale formation and wax precipitation;
and restoring the flow conductivity of the hydraulic fracture.
Further, the scale and wax inhibitor enters hydraulic fractures of a target stratum together with the fracturing propping agent, and specifically comprises the following components:
the granular scale and wax inhibiting agent is positioned between granule gaps of the fracturing propping agent, granules with two grain sizes jointly enter hydraulic fractures of a target stratum, the fracturing propping agent is used for propping the hydraulic fractures, and the scale and wax inhibiting agent contacts stratum fluid in the hydraulic fractures after entering the target stratum.
Preferably, the granular scale and wax inhibitor is in a spherical shape, and the grain diameter of the granular scale and wax inhibitor is 0.15 mm.
The invention has the following beneficial effects:
after the scale and wax inhibitor is injected into a hydraulic fracture together with a fracturing propping agent, the granular scale and wax inhibitor is positioned between granule gaps of the fracturing propping agent, granules with two grain sizes jointly enter the hydraulic fracture of a target stratum, wherein the fracturing propping agent is used for propping the hydraulic fracture, the scale and wax inhibitor contacts stratum fluid in the hydraulic fracture after entering the target stratum and is slowly dissolved into solution, and a solution-like wax inhibiting component can effectively inhibit scaling and wax precipitation in an artificial fracture to the maximum extent, so that the artificial fracture keeps better flow conductivity for a long time, and the yield reduction caused by the reduction of the flow conductivity of the fracture due to scaling and wax precipitation is reduced.
In order to make the aforementioned and other objects of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
FIG. 1 is a schematic representation of a scale and wax inhibitor following entry of a fracturing proppant into a hydraulic fracture of a target formation.
Description of reference numerals:
1. an oil layer; 2. hydraulic fracture profile; 3. a fracturing proppant; 4. scale and wax inhibitor; 5. a wellbore; 6. a perforation section.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.
In the present invention, the upper, lower, left and right in the drawings are regarded as the upper, lower, left and right of the long-acting fracture conductivity maintaining fracturing method described in this specification.
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
The first embodiment:
a first embodiment of the invention is directed to a fracturing method for long-term retention of fracture conductivity, comprising:
injecting a fracturing proppant into the sand mixing truck;
injecting the scale-inhibiting and wax-preventing agent into a sand mixing truck;
continuously stirring the fracturing propping agent and the scale and wax inhibitor in a sand mixing truck;
and injecting the uniformly stirred mixture into the target stratum.
When the petroleum and natural gas deep well is exploited, after the high-closure-pressure low-permeability deposit is subjected to fracturing treatment, the petroleum-containing rock stratum is cracked, the petroleum and gas are collected from a channel formed by the cracks, at the moment, the fluid is required to be injected into the rock base layer so as to exceed the pressure of the fracture strength of the stratum, the rock stratum around the shaft is cracked, a channel with high laminar flow capacity is formed, and in order to keep the cracks formed after fracturing open, the petroleum and gas products can smoothly pass through the channel. The petroleum propping agent enters the stratum along with the high-pressure solution and is filled in the cracks of the rock stratum, so that the cracks are supported and are not closed due to stress release, high flow conductivity is kept, oil and gas are smooth, and the yield is increased.
At present, natural sand or artificial high-strength ceramic particles with certain granularity and gradation are generally adopted as fracturing propping agents in oil field exploitation, the embodiment is described by taking quartz sand propping agents as an example, as shown in figure 1, at least one oil layer 1 is arranged in a shaft 5, and by taking hydraulic fractures in the oil layer 1 as an example, the fracturing propping agents 3 and the scale and wax inhibiting agents 4 are uniformly mixed in a mixing tank of a sand mixing truck, the mixture is pumped into the shaft 5 by the fracturing truck while mixing, and then enters formation fractures through a perforation section 6, and figure 1 is a cross section, so that a hydraulic fracture section 2 can be seen, wherein hollow large particles are the fracturing propping agents 3, solid small particles are the scale and wax inhibiting agents 4, a large amount of the scale and wax inhibiting agents 4 are filled in gaps of the fracturing propping agents 3, and when the fracturing propping agents 3 exert the propping action, the scale and wax inhibiting agents 4 contact formation fluid in the hydraulic fractures, the scale and wax inhibitor is slowly dissolved into solution after meeting formation fluid in the hydraulic fracture, and the scale and wax inhibitor in the solution is attached and contacted with the formation fluid and dissolves scale and wax deposition, so that the flow conductivity of the hydraulic fracture is recovered.
The solid and hollow cores are only illustrated for the fracturing proppant 3 and the scale and wax inhibitor 4 according to fig. 1 to distinguish the two particles to clearly illustrate the positions of the two particles, but do not represent the actual shape in practical applications.
Second embodiment:
the embodiment relates to a fracturing method for long-term maintaining fracture conductivity, which comprises the following steps:
injecting a fracturing proppant into the sand mixing truck;
injecting the scale-inhibiting and wax-preventing agent into a sand mixing truck;
continuously stirring the fracturing propping agent and the scale and wax inhibitor in a sand mixing truck;
and injecting the uniformly stirred mixture into the target stratum.
Wherein, the scale-inhibiting wax-proofing agent is copolymerized by the following components: sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline.
The sodium vinylsulfonate is a water-soluble surfactant, the fatty alcohol-polyoxyethylene ether is a nonionic surfactant, and the two surfactants and the imidazoline are subjected to polymerization reaction to generate a copolymer-scale inhibiting and paraffin preventing agent, so that the wax and scale in an oil well can be prevented from being crystallized and deposited on the surface, the wax dissolution can be promoted, and meanwhile, the corrosion of stratum products to a production column system can be prevented.
Specifically, the scale and wax inhibitor is prepared by the following method:
taking sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline, carrying out copolymerization reaction according to the mass ratio of (0.5-0.8) to (0.8-1.1) to (0.7-1.0), and sequentially diluting, drying and evaporating the generated product to obtain the granular scale and wax inhibitor.
Specifically, the sodium vinylsulfonate, the fatty alcohol-polyoxyethylene ether and the imidazoline may undergo a copolymerization reaction according to a mass ratio of 0.5:0.8:1, or may undergo a copolymerization reaction according to a mass ratio of 0.7:1:0.8, or may undergo a copolymerization reaction according to a mass ratio of 0.8:1.1:0.7, which is only an example, and not limited to this ratio, and may be other ratios according to (0.5-0.8): (0.8-1.1): (0.7-1.0).
The reaction mechanism of the scale and wax inhibitor is as follows:
the granular scale inhibiting and wax preventing agent forms water solution when meeting stratum water and can adhere to wax scale, and small grains of the wax and the scale are coated with one layer of chemical protecting film to change the adhesion capacity between the wax and the scale grains and the pipe wall, so that the small grains are suspended in well fluid and can move freely and can be produced to the ground with oil and water in the production process to avoid aggregation on the wall of crack and pipe column.
Wherein, the dilution refers to mixing and diluting the product with water to 25 to 40 mass percent of the substance, and preparing for the next preparation of the scale-inhibiting and wax-preventing agent.
In order to ensure that the scale and wax inhibitor particles can be filled in the fracturing propping agent particles, the later dissolution of the scale and wax inhibitor particles is convenient to be a solution, the particle size of the prepared granular scale and wax inhibitor is smaller than that of the fracturing propping agent, and the volume ratio of the fracturing propping agent to the scale and wax inhibitor is 58:1 when the two are mixed.
The volume ratio 58:1 of the fracturing propping agent to the scale and wax inhibitor is an optimal ratio obtained through indoor and field test optimization, but the invention is not limited to this, and other ratios are also possible, for example (53-63): (0.5-1.5), and the specific proportion value can be adjusted according to the field condition.
After entering the hydraulic fracture, the scale and wax inhibitor particles are in point contact with the wall of the fracture, and the point contact can reduce the contact area to the minimum, so that the aim is to increase the gap, ensure that the trafficability of formation fluid is better, namely, the flow of the formation fluid is facilitated, and the flow conductivity of the hydraulic fracture is improved.
The third embodiment:
the embodiment provides an application of a fracturing method for long-term maintaining of fracture conductivity, which at least comprises the fracturing method for long-term maintaining of fracture conductivity, and the application is as follows:
selecting a hydraulically fractured oil well as a target well;
selecting a stratum with water conservancy fractures in a target well as a target stratum;
continuously injecting the uniformly stirred mixture of the fracturing propping agent and the scale and paraffin inhibitor into the target well by the sand mixing truck;
the scale and wax inhibitor enters hydraulic fractures of a target stratum together with the fracturing propping agent;
the granular scale and wax inhibitor is slowly dissolved into solution after meeting formation fluid in the hydraulic fracture;
the scale inhibitor and the wax inhibitor in the solution state are attached and contacted with each other and dissolve scale formation and wax precipitation;
and restoring the flow conductivity of the hydraulic fracture.
Wherein the scale-inhibiting and wax-preventing agent enters hydraulic fractures of a target stratum together with the fracturing propping agent, and the method specifically comprises the following steps:
the granular scale and wax inhibiting agent is positioned between granule gaps of the fracturing propping agent, granules with two grain sizes jointly enter hydraulic fractures of a target stratum, the fracturing propping agent is used for propping the hydraulic fractures, and the scale and wax inhibiting agent contacts stratum fluid in the hydraulic fractures after entering the target stratum.
Preferably, the granular scale and wax inhibitor is in a spherical shape, and the grain diameter of the granular scale and wax inhibitor is 0.15 mm.
The spherical scale and wax inhibitor can realize point contact with the fracturing propping agent, compared with surface contact, the point contact can realize the minimum area contact between two particles, further the pore space between the scale and wax inhibitor and the fracturing propping agent is enlarged, the flowing of formation water is further facilitated, namely the trafficability of fluid is increased, and the large trafficability of the formation water can enable the small particles of the scale and wax inhibitor to keep a suspended state and move freely in shaft fluid, and can be produced to the ground along with oil and water in the production process, so that the aggregation on the wall surface of a crack and the wall surface of a pipe column is avoided.
Wherein, the scale-inhibiting wax-proofing agent is copolymerized by the following components: sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline.
The sodium vinylsulfonate is a water-soluble surfactant, the fatty alcohol-polyoxyethylene ether is a nonionic surfactant, and the two surfactants and the imidazoline are subjected to polymerization reaction to generate a copolymer-scale inhibiting and paraffin preventing agent, so that the wax and scale in an oil well can be prevented from being crystallized and deposited on the surface, the wax dissolution can be promoted, and meanwhile, the corrosion of stratum products to a production column system can be prevented.
Specifically, the scale and wax inhibitor is prepared by the following method:
taking sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline, carrying out copolymerization reaction according to the mass ratio of (0.5-0.8) to (0.8-1.1) to (0.7-1.0), and sequentially diluting, drying and evaporating the generated product to obtain the granular scale and wax inhibitor.
In the hydraulic fracturing process, the scale and wax inhibitor particles and the fracturing propping agent are continuously and uniformly mixed in a stirring pool of a sand mixing truck and injected into the stratum, wherein the particle size of the scale and wax inhibitor particles is smaller than that of the fracturing propping agent and mainly positioned in pores between the fracturing propping agent particles, and the scale and wax inhibitor particles and the fracturing propping agent enter hydraulic fractures and are uniformly dispersed and filled in the fractures in the pumping process.
In the production process of oil well fracturing reformation, the scale-inhibiting wax-proofing agent particles are slowly dissolved into a solution after meeting formation fluid, the effective period is 4-6 years, scale formation and wax deposition in the artificial cracks are effectively inhibited, the artificial cracks keep good flow conductivity for a long time, and the yield reduction caused by the reduction of the flow conductivity of the cracks due to scale formation and wax deposition is reduced.
Fourth embodiment:
in the embodiment, a certain block reservoir is used as a target stratum, and a fracturing method for keeping fracture conductivity for a long time is implemented, which specifically comprises the following steps:
a certain block of reservoir is a compact oil layer, the thickness of the reservoir is 16 m, the permeability is 0.15 millidarcy, the porosity is 9.5%, the temperature of the oil layer is 55 ℃, the mineralization degree of formation water is high (85000 mg/L), the wax content and the asphaltene content in crude oil are high, wax deposition and scaling are easy to occur in artificial cracks of an oil well, a straight well is selected as a target test well in the reservoir of the block, the oil well is perforated before fracturing, the length of a perforation section is 4 m, and the hole density is 16 holes/m;
preparing a fracturing unit 1 set, wherein 35 cubic meters of a 20/40-mesh quartz sand (the particle diameter is 0.425-0.85 mm) propping agent, 0.6 cubic meter of a granular solid scale inhibiting and paraffin preventing agent and 165 cubic meters of guanidine gum fracturing fluid are injected into a pad fluid by a pump injection displacement of 2.5 cubic meters/minute, then a sand carrying fluid is started to be pumped after 30 cubic meters of the pad fluid are injected, the scale inhibiting and paraffin preventing agent and the quartz sand are uniformly mixed in a mixing tank of a sand mixing truck, the mixture is pumped into a shaft by a fracturing truck while mixing, then the mixture enters a stratum fracture, the sand carrying fluid is injected into the stratum fracture together by 110 cubic meters, then the fracturing construction is finished after 25 cubic meters of a displacement fluid is pumped, and a well is closed to wait for the fracture to be closed;
after the pump is stopped, the crack is gradually closed, the scale and wax inhibitor in the crack and the quartz sand propping agent are uniformly dispersed, and in the production process of an oil well, the scale and wax inhibitor particles in the crack are slowly dissolved after contacting with formation fluid, so that the scale and wax inhibitor is released, and the flow conductivity of the crack is kept for a long time.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.
Claims (7)
1. A fracturing method for long-term maintaining fracture conductivity is characterized by comprising the following steps:
injecting a fracturing proppant into the sand mixing truck;
injecting the scale-inhibiting and wax-preventing agent into a sand mixing truck;
continuously stirring the fracturing propping agent and the scale and wax inhibitor in a sand mixing truck;
and injecting the uniformly stirred mixture into the target stratum.
2. The fracturing method of claim 1, wherein the scale and wax inhibitor is prepared by copolymerizing: sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline.
3. The fracturing method of claim 2, wherein the scale and wax inhibitor is prepared by the following method:
taking sodium vinylsulfonate, fatty alcohol-polyoxyethylene ether and imidazoline, carrying out copolymerization reaction according to the mass ratio of (0.5-0.8) to (0.8-1.1) to (0.7-1.0), and sequentially diluting, drying and evaporating the generated product to obtain the granular scale and wax inhibitor.
4. The fracturing method of claim 3 wherein the granular scale and wax inhibitor has a particle size smaller than that of the fracturing proppant and the volume ratio of the fracturing proppant to the scale and wax inhibitor is 58:1 when mixed.
5. The application of the long-acting fracture conductivity maintaining fracturing method at least comprises the long-acting fracture conductivity maintaining fracturing method as claimed in any one of claims 1-4, and is characterized in that the application comprises the following steps:
selecting a hydraulically fractured oil well as a target well;
selecting a stratum with water conservancy fractures in a target well as a target stratum;
continuously injecting the uniformly stirred mixture of the fracturing propping agent and the scale and paraffin inhibitor into the target well by the sand mixing truck;
the scale and wax inhibitor enters hydraulic fractures of a target stratum together with the fracturing propping agent;
the granular scale and wax inhibitor is slowly dissolved into solution after meeting formation fluid in the hydraulic fracture;
the scale inhibitor and the wax inhibitor in the solution state are attached and contacted with each other and dissolve scale formation and wax precipitation;
and restoring the flow conductivity of the hydraulic fracture.
6. The use of a long-lasting fracture conductivity maintaining fracturing method as claimed in claim 5, wherein said scale and wax inhibitor is co-introduced into the hydraulic fractures of the target formation with the fracturing proppant, in particular:
the granular scale and wax inhibiting agent is positioned between granule gaps of the fracturing propping agent, granules with two grain sizes jointly enter hydraulic fractures of a target stratum, the fracturing propping agent is used for propping the hydraulic fractures, and the scale and wax inhibiting agent contacts stratum fluid in the hydraulic fractures after entering the target stratum.
7. The application of the long-acting fracturing method for maintaining the flow conductivity of the fracture as claimed in claim 5, wherein the granular scale and wax inhibitor is in a spherical shape with a grain diameter of 0.15 mm.
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