CN109653723B - Method for increasing volume fracturing effect of complex oil and gas layer fracture network - Google Patents
Method for increasing volume fracturing effect of complex oil and gas layer fracture network Download PDFInfo
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- CN109653723B CN109653723B CN201811239598.4A CN201811239598A CN109653723B CN 109653723 B CN109653723 B CN 109653723B CN 201811239598 A CN201811239598 A CN 201811239598A CN 109653723 B CN109653723 B CN 109653723B
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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
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- E21B43/26—Methods for stimulating production by forming crevices or fractures
Abstract
The invention relates to the technical field of oilfield fracturing acidification, in particular to a method for increasing the fracturing effect of a complex oil and gas layer fracture network volume, which comprises the following steps: the method comprises the following steps of firstly, modifying a plane seam network, secondly, forming a tackified branch seam, thirdly, forming an artificial crack, fourthly, modifying a three-dimensional seam network, and fifthly, filling sand in the artificial crack; and sixthly, injecting displacement fluid, closing the well for a period of time, opening the well, discharging the fluid, and testing the oil gas yield. The invention can carry out fracture network volume fracturing reconstruction around the perforation point to the maximum extent, and improve the reconstruction volume of the fracture and the long-term performance of the flow conductivity and the stable production period after the fracture are compressed to the maximum extent, and the method can save 10 to 30 percent of operation fluid.
Description
Technical Field
The invention relates to the technical field of oilfield fracturing acidification, in particular to a method for increasing the fracturing effect of a complex oil and gas layer fracture network volume.
Background
The complex hydrocarbon reservoir in the invention refers to: the lithology is shale, sandstone or volcanic rock, the crack filling material is calcite mineral, clay mineral or other silicate mineral, and the minerals occupy a certain proportion in the reservoir to form a crack reservoir. The reservoirs are characterized by deep burial and complicated lithology and mainly comprise mud, argillaceous carbonate rock and grey mudstone; sometimes, the method has the characteristics of high clay content, strong water sensitivity, poor physical properties of reservoirs and the like, so that the reservoir transformation process has high selection difficulty, difficult fracturing sand addition and low construction success rate. In order to solve the problems, on the basis of the adaptability analysis of the early-stage reservoir transformation process, the research on the fracture-network volume fracturing process has been carried out successively by various domestic related research institutions. At present, fracture network volume fracturing becomes an important means for modifying fractured oil and gas reservoirs. With the continuous deepening of the development of fracture-type complex oil and gas fields, the defects of different degrees of well yield increasing effect of fracture network volume fracturing are always found, and the defects are mainly manifested by poor yield increasing effect, fast decrease of pressure and yield after fracturing and short stable production period.
Aiming at the characteristics of a complex lithologic reservoir, an oil reservoir is taken as a modification object, different fracturing technologies are preferably selected to increase the effective production increasing volume of the reservoir, and the application of the oil reservoir modification volume on the complex oil-gas layer is explored, so that the initial yield and the final recovery ratio of the complex oil-gas layer are improved. As reported in the application of the complicated lithologic reservoir volume fracturing technology of the helar oil field in 2015, volume 4, of "oil and gas well test" of 8 months: because the reservoir stratum uses a fracture network volume fracturing process, the oil increasing effect is obvious, the average daily oil production of a single well is increased by 6.0t from 1.7t after ordinary fracturing, and the average daily oil production of the single well is increased by 4.4t from 0.8t after ordinary fracturing.
Patent CN105275446A discloses a volume fracturing modification method, which includes injecting low-viscosity fracturing fluid to saturate the microcracks of the near-well formation with the low-viscosity fracturing fluid, and then injecting sand-mixed fracturing fluid containing small-particle-size proppant for plugging the microcracks and polishing to reduce bending friction, so as to reduce the near-well effect and ensure the formation of dominant channels of main fractures; and alternately injecting high-viscosity fracturing fluid and low-viscosity fracturing fluid to enable the generated main fracture to continuously extend and extend from the near-well stratum to the middle-far well stratum and be communicated with the far-field natural fracture and the weak surface bedding seam, and injecting sand-mixing fracturing fluid containing medium-particle size proppant to support the main fracture and injecting sand-mixing fracturing fluid containing large-particle size proppant to complete fracture opening support.
Patent CN106703778A discloses a method for improving fracture reconstruction volume by shale, which comprises the following steps of (1) finely analyzing and evaluating brittleness index of the shale; selecting a proper number of cluster perforation holes; thirdly, each section is subjected to induced test fracturing; fourthly, judging acid pretreatment; fifthly, further treating the cracks according to the original horizontal stress difference of the shale relative to the net pressure of the main cracks; and sixthly, throwing the ball according to the number of clusters of the perforation and the total number of the perforation. Wherein, the acid pretreatment is carried out before the pressure, the main application is to clean perforation holes and reduce the rupture pressure, the dosage of the acid liquor is not more than 10m3, and the acid liquor is a common earth acid and hydrochloric acid system.
Due to the complex diversity of fractured reservoirs, the conventional fracture network volume fracturing technology cannot obtain good regular yield increasing effect at present, and the most obvious characteristics are that the wells with complex oil and gas reservoirs have rapid yield decrement after fracturing and short yield increasing effective period, and the main reasons are that: the method has the advantages that at the present, most of sliding water used in the pre-stage of volume fracturing belongs to non-reactive liquid, has no reactivity with the wall surface of a crack, only relies on ground equipment to provide strong power, and forms a simple mechanical expansion effect on a crack channel, and the crack closing flow guide capacity of the sliding water is reduced at a high speed under certain reservoir closing pressure after fracturing, and generally, the flow guide capacity of the crack is basically recovered to the level before fracturing under 30 MPa. Secondly, the three-dimensional performance of the existing volume fracturing is not strong, the extension and development of the fracture are influenced by the ground stress and the original direction of the fracture, the approximate shape is developed on a certain plane by taking a perforation point as the center, and an irregular oval body with low thickness is formed, so that the yield increasing effect of the body is limited. And thirdly, performing fracture network volume fracturing construction on some wells with the well depth of more than 3000m, wherein the well mouth construction pressure is generally very high. Limited by ground equipment, the capability of extending the cracks is difficult to continue to be increased by a method of improving the construction discharge capacity, theoretically, the extending length of the cracks is limited, and the size of the formed crack net is small, so that the crack net volume fracturing effect of deep wells and ultra-deep wells is not large.
Disclosure of Invention
The invention provides a method for increasing the fracture network volume fracturing effect of a complex oil and gas formation, overcomes the defects of the prior art, and can effectively solve the problems of poor regularity of the yield increasing effect, quick decrease of pressure and yield after fracturing and short stable production period of the conventional fracture network volume fracturing technology at present.
The technical scheme of the invention is realized by the following measures: a method for increasing the volume fracturing effect of a complex oil and gas layer fracture network is carried out according to the following steps: the method comprises the following steps of firstly, modifying a plane fracture network, and sequentially and alternately injecting non-acidic slickwater and acidic slickwater into a plane fracture of a fracture type reservoir stratum near a perforation point; secondly, forming a tackified branch seam, tackifying the non-acidic slick water and the acidic slick water, and adding a propping and steering agent; thirdly, forming artificial cracks, injecting water-based fracturing fluid, and forming artificial cracks with the crack length of not less than 100 meters on two sides of a perforation point; fourthly, three-dimensional seam net reconstruction, namely injecting non-acidic slick water and acidic slick water alternately in sequence, performing seam net volume fracturing reconstruction on the wall surface of the artificial crack, tackifying the non-acidic slick water and the acidic slick water in a slug mode for at least three times, and adding a supporting steering agent; fifthly, filling sand in the artificial cracks; and sixthly, injecting displacement fluid, closing the well for a period of time, opening the well, discharging the fluid and producing oil gas.
The following is further optimization or/and improvement of the technical scheme of the invention:
the acidic slickwater comprises 5-25 parts of hydrochloric acid, 0-8 parts of hydrofluoric acid, 1-2 parts of corrosion inhibitor, 0.5-1 part of citric acid, 0.5-1 part of cleanup additive and 0.5-2.5 parts of resistance reducing agent, and the acidic slickwater needs to meet the requirements that the corrosion inhibition rate is less than or equal to 0.5g/m2 & h, the resistance reducing rate is more than or equal to 40% compared with clear water, the viscosity of acid liquor is less than or equal to 10mPa & s, the optimal viscosity value is 2-8 mPa & s, and the surface tension is less than or equal to 25 mN/m.
The corrosion inhibitor in the acidic slickwater is an imidazoline corrosion inhibitor; or/and the cleanup additive is a fluorocarbon type cleanup additive; or/and the resistance reducing agent is an acid-resistant resistance reducing agent which is formed by copolymerizing acrylamide monomers and other acid-resistant and salt-resistant monomers and has a molecular weight of 600-1000 ten thousand.
The adding amount of the hydrochloric acid and the hydrofluoric acid in the acidic slick water is specifically as follows: when the content of acid-soluble mineral substances in the reservoir is 0-5% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 4 parts; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 2 parts; when the content of acid-soluble minerals in the reservoir is 25-50% and the main component of the acid-soluble minerals is calcite, the addition amount of hydrochloric acid is 15-25 parts and the addition amount of hydrofluoric acid is 1 part; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the addition amount of the hydrochloric acid is 15-25 parts, and the hydrofluoric acid is not added.
In the first step and the fourth step, the matching relationship between the acidic slick water and the non-acidic slick water is as follows: when the content of the acid-soluble mineral substance in the reservoir is 0-5 percent and the main components of the acid-soluble mineral substance are clay and silicate, the injection amount of the acid slickwater is VGeneral assembly5% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the injection amount of the acidic slickwater is VGeneral assembly25% of red mark; when the content of acid-soluble mineral substances in the reservoir is 25-50% and the main component of the acid-soluble mineral substances is calcite, the injection amount of the acidic slickwater is VGeneral assembly50% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the injection amount of the acid slickwater is VGeneral assembly80% of the total weight; wherein, VGeneral assemblyIs the sum of the volume of sour and non-sour slick water.
In the first step, the construction discharge capacity of acid liquor in the acidic slippery water is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the acid slick water and the non-acid slick water is not less than 5m3/min。
In the second step, the method for tackifying the non-acidic slippery water and the acidic slippery water is to add 3 to 5 percent of alkyl quaternary ammonium salt, 0.5 to 2 percent of sodium benzoate and 1 to 3 percent of potassium chloride into the acidic slippery water and the non-acidic slippery water in the construction process to increase the viscosity of the acidic slippery water and the non-acidic slippery water to 5 to 15 mPa.s, wherein the alkyl quaternary ammonium salt is more than one of dodecyl ammonium chloride, tetradecyl ammonium chloride and gemini quaternary ammonium salt.
In the second step, the supporting diverting agent is ceramsite with 40 meshes to 70 meshes, and is added according to the proportion of 1 percent to 8 percent of the total amount of the non-acidic slick water and the acidic slick water.
In the second step, the non-sour and sour slicks are tackified and a proppant diverter is added and added in slug form.
In the fourth step, the construction discharge amount of the acid liquor in the acidic slipstream is 5m3Min to 12m3And/min, wherein the acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge amount of the injected acidic slickwater and the injected non-acidic slickwater is at least 1.2 times of the discharge amount of the acidic slickwater and the non-acidic slickwater injected in the first step.
In the fifth step, the water-based fracturing fluid is a guanidine gum fracturing fluid which comprises 0.35 to 0.5 parts of hydroxypropyl guanidine gum powder, 0.5 to 3 parts of cleanup additive, 0.03 to 0.8 part of pH value regulator, 0.1 to 2 parts of organic boron crosslinking agent and 0.01 to 0.1 part of gel breaker, and the guanidine gum fracturing fluid needs to meet the following requirements: 170S at reservoir temperature-1The viscosity after shearing for 1 hour is more than or equal to 70 mPas, the surface tension of the gel breaking liquid is less than or equal to 25mN/m, and the viscosity of the gel breaking liquid is less than or equal to 5 mPas.
The non-acidic slickwater comprises 0.5 to 1 part of discharge assistant and 0.08 to 0.2 part of emulsion polyacrylamide with the molecular weight M of 500 to 900 ten thousand, and the non-acidic slickwater needs to meet the following requirements: compared with clear water, the drag reduction rate is more than or equal to 60 percent, the viscosity is less than or equal to 10 mPa.s, the optimal viscosity value is 2 to 8 mPa.s, and the surface tension is less than or equal to 25 mN/m.
The discharge assistant in the non-acidic slick water is a fluorocarbon type water-based fracturing discharge assistant, and the fluorocarbon type water-based fracturing discharge assistant is preferably KML-ZP acidification discharge assistant or YL-103 acidification discharge assistant.
The invention increases the capability of the crack to continue to expand and extend forwards, can increase the extending pressure at the tail end of the peracid microcrack to a great extent, thereby increasing the extending length of the microcrack, and can maximally perform fracture network volume fracturing transformation around a perforation point, the acidic slickwater in the invention can solve the problems of rapid decrease of fracture conductivity, rapid decrease of post-fracturing yield and short effective period in the current complex oil-gas reservoir volume fracturing, furthest improves the long-term of the transformation volume and the conductivity of the crack and the post-fracturing stable period, improves the fracturing transformation effect and the reservoir exploitation degree of the reservoir, is analyzed from another angle, if the volume transformation effect reached by the conventional slickwater volume fracturing, 10 to 30 percent of operation fluid can be saved by using the method of the invention, so the cost can be saved by using the acidic slickwater, the flowback of the fracturing fluid is also facilitated; the invention has the greatest highlight that the irregular elliptic body seam network volume fracturing effect with low thickness on the conventional plane is improved to the seam network volume fracturing effect with higher three-dimensional degree, so that a network crack system around a perforation point is more complex and developed, the fracturing effect is better than the seam network volume fracturing effect generated by using non-acid slickwater construction, and the reconstruction effect of the seam network volume near a shaft is maximized.
Drawings
FIG. 1 is a formula of the volume increasing capability of the slotted net of the present invention.
FIG. 2 is a formula of fracture propagation pressure increase capability in the present invention.
Detailed Description
The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention. The various chemical reagents and chemical articles mentioned in the invention are all the chemical reagents and chemical articles which are well known and commonly used in the prior art unless otherwise specified; the percentages in the invention are mass percentages unless otherwise specified; the water in the present invention is tap water or purified water, if not specifically mentioned; the solution in the present invention is an aqueous solution in which the solvent is water, for example, a hydrochloric acid solution is an aqueous hydrochloric acid solution, unless otherwise specified; ordinary temperature in the present invention generally means a temperature of 15 ℃ to 25 ℃, and is generally defined as 25 ℃.
The invention is further described with reference to the following examples and figures:
example 1, the method for increasing the fracturing effect of the fracture network volume of the complex oil and gas formation is characterized by comprising the following steps: the method comprises the following steps of firstly, modifying a plane fracture network, and sequentially and alternately injecting non-acidic slickwater and acidic slickwater into a plane fracture of a fracture type reservoir stratum near a perforation point; secondly, forming a tackified branch seam, tackifying the non-acidic slick water and the acidic slick water, and adding a propping and steering agent; thirdly, forming artificial cracks, injecting water-based fracturing fluid, and forming artificial cracks with the crack length of not less than 100 meters on two sides of a perforation point; fourthly, three-dimensional seam net reconstruction, namely injecting non-acidic slick water and acidic slick water alternately in sequence, performing seam net volume fracturing reconstruction on the wall surface of the artificial crack, tackifying the non-acidic slick water and the acidic slick water in a slug mode for at least three times, and adding a supporting steering agent; fifthly, filling sand in the artificial cracks; and sixthly, injecting displacement fluid, closing the well for a period of time, opening the well, discharging the fluid and producing oil gas.
In the first step, planar fracture network volume fracturing modification is carried out on a reservoir layer near a perforation point, non-acidic slickwater plays a role in reaming, acidic slickwater plays a role in corrosion, the non-acidic slickwater and the acidic slickwater are sequentially and alternately injected to play a role in reaming and corrosion alternation, so that the wall surface of a fracture and soluble minerals in the fracture can be effectively corroded to further ream the propped microcracks, according to Darcy's law, the extension pressure of the tail ends of peracid microcracks can be increased to a great extent, the capacity of continuing forward extension of the fractures is increased, and the extension length of the microcracks is increased; non-acidic slickwater is a well known prior art. And in the second step, the slickwater is tackified on the basis of continuous construction, so that the propping and steering agent can be uniformly dispersed in the slickwater and uniformly enters a plurality of extended micro-cracks, and the propping and steering agent is prevented from being aggregated into a cluster or being uniformly dispersed in a fluid due to the low viscosity of the slickwater in the process of transporting the propping and steering agent from a wellhead to the micro-cracks, so that the propping and steering agent in each crack enters non-uniformly to influence the formation and extension of main cracks and branch cracks. In the third step, the water-based fracturing fluid is the prior known technology and is water-based guanidine gum fracturing fluid or acidic carboxymethyl guanidine gum fracturing fluid or associated fracturing fluid or polyacrylamide fracturing fluid. And step four, tackifying the slick water in a slug mode for at least three times, and adding a propping diverter to ensure that the subsequent sand filling operation of the artificial fracture has ideal filtration performance.
Example 2, as an optimization of the above examples, sour slick water comprises 5 to 25 partsThe corrosion inhibitor comprises hydrochloric acid, 0 to 8 parts of hydrofluoric acid, 1 to 2 parts of corrosion inhibitor, 0.5 to 1 part of citric acid, 0.5 to 1 part of cleanup additive and 0.5 to 2.5 parts of resistance reducing agent, wherein the acid slickwater needs to meet the requirements that the corrosion inhibition rate is less than or equal to 0.5g/m2 h, the resistance reducing rate is more than or equal to 40 percent compared with clear water, the viscosity of acid liquor is less than or equal to 10mPa s, the optimal viscosity value is 2 to 8mPa s, and the surface tension is less than or equal to 25 mN/m. The acidic slickwater has good corrosion inhibition effect, and under the condition of optimal using amount, the corrosion inhibition rate is less than or equal to 0.5g/cm2H; the harm caused by acid corrosion of the oil casing is minimized.
Example 3, as an optimization of the above example 2, the corrosion inhibitor in the acid slickwater was an imidazoline type corrosion inhibitor; or/and the cleanup additive is a fluorocarbon type cleanup additive; or/and the resistance reducing agent is an acid-resistant resistance reducing agent which is formed by copolymerizing acrylamide monomers and other acid-resistant and salt-resistant monomers and has a molecular weight of 600-1000 ten thousand. The imidazoline type corrosion inhibitor is preferably KML-HS acidizing corrosion inhibitor or ALS-2 acidizing corrosion inhibitor, the KML-HS acidizing corrosion inhibitor is produced by Claritycor American chemical industry, Inc., and the ALS-2 acidizing corrosion inhibitor is produced by plasticizer factory in Shandong Anqiu; the cleanup additive is preferably KML-ZP acidifying cleanup additive or YL-103 acidifying cleanup additive, the KML-ZP acidifying cleanup additive is produced by Clarithrome chemical industry, Inc., and the YL-103 acidifying cleanup additive is produced by the marketing department of Yunlong chemical materials, Inc.; the resistance reducing agent is preferably HJZ-2 high-temperature acid liquid resistance reducing agent or KML-JZ1 emulsion resistance reducing agent, the HJZ-2 high-temperature acid liquid resistance reducing agent is produced by a division of petroleum exploration and development science research institute, and the KML-JZ1 emulsion resistance reducing agent is produced by Clarithromi chemical industry Limited liability company.
Example 4, as the optimization of examples 2 and 3, the addition amounts of hydrochloric acid and hydrofluoric acid in the acidic slick water are specifically as follows: when the content of acid-soluble mineral substances in the reservoir is 0-5% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 4 parts; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 2 parts; when the content of acid-soluble minerals in the reservoir is 25-50% and the main component of the acid-soluble minerals is calcite, the addition amount of hydrochloric acid is 15-25 parts and the addition amount of hydrofluoric acid is 1 part; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the addition amount of the hydrochloric acid is 15-25 parts, and the hydrofluoric acid is not added.
Example 5 as an optimization of the above example, the matching relationship between the acid slick water and the non-acid slick water in the first step and the fourth step is as follows: when the content of the acid-soluble mineral substance in the reservoir is 0-5 percent and the main components of the acid-soluble mineral substance are clay and silicate, the injection amount of the acid slickwater is VGeneral assembly5% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the injection amount of the acidic slickwater is VGeneral assembly25% of red mark; when the content of acid-soluble mineral substances in the reservoir is 25-50% and the main component of the acid-soluble mineral substances is calcite, the injection amount of the acidic slickwater is VGeneral assembly50% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the injection amount of the acid slickwater is VGeneral assembly80% of the total weight; wherein, VGeneral assemblyIs the sum of the volume of sour and non-sour slick water. In the step, a certain proportion of the acidic slickwater to the non-acidic slickwater is required, and the main reason is that the content of the acidic soluble minerals in some complex oil and gas reservoirs with smaller acidic soluble minerals, such as shale reservoirs, can be 2% smaller, and if the acidic slickwater is used in the whole process of the reservoirs, excessive acid liquor can be wasted, and the operation cost is increased.
Example 6 As an optimization of the above example, the first step, the acid liquor displacement in the acid slipstream was 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the acid slick water and the non-acid slick water is not less than 5m3/min。
Example 7 as an optimization of the above example, in the second step, the non-acidic slickwater and acidic slickwater are tackified by adding 3% to 5% of alkyl quaternary ammonium salt, 0.5% to 2% of sodium benzoate, and 1% to 3% of potassium chloride to the acidic slickwater and non-acidic slickwater during construction to increase the viscosity of the acidic slickwater and non-acidic slickwater to 5mPa · s to 15mPa · s, wherein the alkyl quaternary ammonium salt is one or more of dodecyl ammonium chloride, tetradecyl ammonium chloride, and gemini quaternary ammonium salt.
Example 8, as an optimization of the above example, in the second step, the proppant diverting agent is a ceramsite of 40 mesh to 70 mesh, and is added in a proportion of 1% to 8% of the total amount of the non-acid slick water and the acid slick water.
Example 9, as an optimization of the above example, in a second step, the non-sour and sour slicks were viscosified and proppant diverting agents were added, and added in slug form.
Example 10 As an optimization of the above example, in the fourth step, the discharge amount of acid solution in the acid slipstream was 5m3Min to 12m3And/min, wherein the acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge amount of the injected acidic slickwater and the injected non-acidic slickwater is at least 1.2 times of the discharge amount of the acidic slickwater and the non-acidic slickwater injected in the first step.
Example 11, as an optimization of the above example, in the fifth step, the water-based fracturing fluid is a guanidine gum fracturing fluid, which comprises 0.35 to 0.5 parts of hydroxypropyl guanidine gum powder, 0.5 to 3 parts of cleanup additive, 0.03 to 0.8 parts of pH regulator, 0.1 to 2 parts of organic boron crosslinking agent, and 0.01 to 0.1 parts of gel breaker, and the guanidine gum fracturing fluid needs to satisfy the following conditions: 170S at reservoir temperature-1The viscosity after shearing for 1 hour is more than or equal to 70 mPas, the surface tension of the gel breaking liquid is less than or equal to 25mN/m, and the viscosity of the gel breaking liquid is less than or equal to 5 mPas.
Example 12, as an optimization of the above examples, the non-acidic slickwater includes 0.5 to 1 part of the cleanup additive, 0.08 to 0.2 parts of the emulsion polyacrylamide having a molecular weight M of 500 to 900 ten thousand, and the non-acidic slickwater is required to satisfy: compared with clear water, the drag reduction rate is more than or equal to 60 percent, the viscosity is less than or equal to 10 mPa.s, the optimal viscosity value is 2 to 8 mPa.s, and the surface tension is less than or equal to 25 mN/m.
Example 13, as an optimization of the above example 12, the drainage aid in the non-acidic slickwater was a fluorocarbon type water-based fracturing drainage aid. The fluorocarbon type water-based fracturing cleanup additive is preferably KML-ZP acidification cleanup additive or YL-103 acidification cleanup additive. The KML-ZP acidifying cleanup additive is produced by Clarityco Meili chemical industry, Inc., and the YL-103 acidifying cleanup additive is produced by the marketing department of Yunlong chemical materials, Inc.
The invention can effectively improve the technical effect of the existing seam net volume fracturing and has good practicability.
The acidic slickwater provided by the invention integrates the performances of conventional slickwater and acid liquor, can replace conventional slickwater in a complex oil-gas layer, and can realize that the field discharge capacity is more than or equal to 8m3Performing fracture construction on the seam net volume in min; the invention uses acid slickwater, and the main technical purpose is as follows:
the method comprises the following steps of (1) carrying out corrosion on the wall surface of a crack and soluble minerals in the crack to further expand the propped micro crack and increase the pressure transmission capacity; according to Darcy's law, the pressure difference between two ends of the peracid microcrack can be reduced by 0.5-3 times, the extension pressure at the tail end of the peracid microcrack is increased to a great extent, the capability of the crack for continuously expanding and extending forwards is increased, and the volume of the seam network is increased;
secondly, due to the corrosion of acid liquor on the wall surface of the crack, the roughness of the crack surface is changed, and the flow conductivity of the closed crack is increased, so that the invention can furthest improve the long-term performance of the volume and the flow conductivity of the crack modification and the stable production period after the fracture is closed, and improve the fracture modification effect and the reservoir utilization degree of the reservoir. From another angle, if the volume transformation effect achieved by volume fracturing of the conventional slickwater is achieved, 10-30% of operation fluid can be saved by using the method, so that the cost can be saved by using the acidic slickwater, and the flowback of the fracturing fluid is facilitated; the invention divides the fracture reconstruction into two parts, wherein the first part is to reconstruct a micro-fracture system in a near wellbore zone: the extension and development of the crack are influenced by the ground stress and the original direction of the crack, the approximate seam network volume shape is an irregular ellipse body which develops on a certain plane by taking a perforation point as the center and has low thickness, in the first part of seam network volume transformation, slick water is respectively tackified according to the actual design requirement, so that the viscosity of acidic slick water and non-acidic slick water is increased to a slug from 5 mPa.s to 15 mPa.s, the main function of the slug is to carry a supporting and steering agent, the technical aim is that in the extension process of a micro-crack, the steering agent plays a supporting and blocking role, the development of a main crack is stopped timely, a plurality of branch cracks can be 'suppressed' at the stopping position, so that a seam network system is more complex, namely the main crack and the branch cracks exist, and the main crack and the branch cracks at different positions are mutually communicated, thereby realizing a large-scale 'network crack' system, the construction efficiency is improved, and in order to increase the three-dimensional performance of volume fracturing, a section of high-viscosity fluid is utilized to manufacture artificial cracks with certain symmetry and length, width and height formed on two sides of a perforation point; the acid slickwater and the non-acid slickwater in the second part perform sufficient fracture network volume fracturing transformation on the micro-fracture system contacted on the wall surface of the artificial fracture, the construction displacement of the second part is more than 1.2 times of that of the first part, all the micro-fractures on the wall surface of the fracture are ensured to be transformed, and the support steering slug is performed for at least 3 times, so that the ideal filtration property is achieved when subsequent sand filling operation is ensured; the fracture network volume fracturing process mode is more beneficial to communicating more new fractures, a three-dimensional fracture network transformation system is formed, and finally the fracturing fluid with mixed sand and containing the proppant with large particle size is injected to complete the support of the artificial fracture.
The formula of the capability of increasing the volume of the slotted net is shown in the attached figure 1:
wherein: 1. beta: the calculation formula of fracture extension pressure increasing capacity,%, beta is shown in figure 2;
2、Vbtotal amount of slickwater used in the three-dimensional fracture modification step, m3；
3. Va is the total amount of slickwater used in conventional slotted net volume fracturing reformation, m3；
4. A1 and A2 are parameters related to erosion amount and shape, and can be determined by experiments;
5. c% is the total concentration of the acid liquor.
The invention is mainly characterized in that:
1. in a complex oil-gas layer, the invention uses the acidic slickwater to replace the conventional slickwater, and realizes that the field discharge capacity is more than or equal to 8m3The construction of the volume fracturing is carried out in the/min,the method mainly aims to dissolve and corrode soluble minerals on the wall surface of the crack and in the crack to further expand the propped micro crack, and according to Darcy's law, the extending pressure at the tail end of the peracid micro crack can be increased to a great extent, so that the capability of the crack for continuing expanding and extending forwards is increased, the extending length of the micro crack is increased, fracture network volume fracturing reconstruction is performed around a perforation point to the maximum extent, symmetrical artificial cracks are formed on two wings of a shaft by using water-based sand-carrying fracturing fluid, the three-dimensional fracture network volume fracturing reconstruction is performed on a micro crack system on the wall surface of the artificial crack, and finally the sand filling operation of the artificial crack is completed.
2. The acidic slickwater has the earth acid characteristic, can etch clay, silicate and partial matrix components in the cracks, increases the hole expanding capability and increases the roughness of the wall surfaces of the cracks, so that the acidic slickwater can solve the problems of rapid decrease of the flow conductivity of the cracks, rapid decrease of the yield after the cracks and short effective period in the volume fracturing of the current complex oil-gas reservoir, furthest improves the long-term property of the transformation volume and the flow conductivity of the cracks and the stable yield period after the cracks, and improves the fracturing transformation effect and the reservoir utilization degree of the reservoir; from another angle, if the volume transformation effect achieved by volume fracturing of the conventional slickwater is achieved, 10-30% of operation fluid can be saved by using the method, so that the cost can be saved by using the acidic slickwater, and the flowback of the fracturing fluid is facilitated;
3. the invention has the greatest highlight that the irregular elliptic seam net volume fracturing effect with low thickness on the conventional plane is improved to the seam net volume fracturing effect with higher three-dimensional degree. Therefore, the method utilizes a section of high-viscosity fluid to manufacture the artificial fracture which is symmetrical on two sides of a perforation point and has certain length, width and height; and then, carrying out sufficient fracture network volume fracturing on a microcrack system contacted on the wall surface of the artificial fracture by utilizing the acidic slickwater and the non-acidic slickwater, wherein the construction discharge capacity of the section is more than 1.2 times higher than that of the planar fracture network transformation step, and ensuring that all microcracks on the wall surface of the fracture are fully transformed, so that a network fracture system around a perforation point is more complex and developed, the fracturing effect of the network fracture system is better than that of the fracture network volume fracturing effect generated by the non-acidic slickwater construction, and the fracture network volume transformation effect near a shaft is maximized.
4. The method is simple and easy to implement on-site construction, can reduce the using amount of slickwater, can carry out integrated construction in a ready-to-use and ready-to-prepare mode, is convenient for on-site operation, and is mainly suitable for carrying out fracture network volume fracturing transformation construction on a fracture type complex oil-gas reservoir with the reservoir temperature of less than or equal to 120 ℃ and the reservoir depth of less than or equal to 5000 m.
The present invention will be described in further detail with reference to specific examples.
The well A is a straight well of a certain block, the reservoir is a chalk-based volcanic fractured reservoir, the oil and gas display layer interval is 3322.6m to 3352.9m, the lithology is that the reservoir contains a small amount of calcite and a argillaceous fracture is filled, and the specific composition analysis of the minerals of the whole well is shown in the table 1. The perforation section is 3325m to 3331m, the formation temperature is 86 ℃, and the pressure gradient is 2.14MPa/100 m. Permeability 0.1mD to 0.4mD, porosity 5.5% to 9.8%. The core acid etching rate is 30.5%. From the view of coring property, the filling materials are mainly limestone and a small amount of calcite and argillaceous substances, react with dilute hydrochloric acid, and cracks develop relatively. By adopting the complex hydrocarbon reservoir efficiency enhancement method provided by the invention, a seam-net volume fracturing scheme is designed.
The specific implementation method comprises the following steps:
1. the scale of the volume fracturing construction is shown in Table 2
2. Acidic slick water
The acid slickwater formula comprises the following steps:
10% of hydrochloric acid, 3% of hydrofluoric acid, 1.5% of ALS-2 acidizing corrosion inhibitor, 1% of citric acid, 1% of KML-ZP acidizing cleanup additive and 1.2% of KML-JZ1 emulsion resistance reducer. The balance of water;
the performance indexes of the acidic slickwater are shown in the table 3;
the acid slip liquid amount:
the total liquid volume of the slickwater is 800m3(ii) a The dosage of the planar slotted net in volume fracturing is 500m3The dosage of the three-dimensional slotted net in volume fracturing is 300m3；
Acidic slickwater and conventional slickwater are distributed in proportion
The using amount of slickwater in the volume fracturing of the plane slotted net is 500m3Wherein the acidic slickwater amount is 500 x 50 percent to 250m3The amount of the conventional slick water liquid is 500m3-250m3＝250m3(ii) a The dosage in the three-dimensional seam net volume fracturing is 300m3The amount of acidic slick water is 300 x 50% ═ 150m3The amount of the conventional slick water liquid is 300m3-150m3＝150m3；
3. Non-acidic conventional slickwater formula
0.02% of emulsion polyacrylamide, 0.5% of KML-ZP cleanup additive and 1% of potassium chloride. The balance of water;
4. guanidine gum fracturing fluid
The method comprises the following steps: 0.45 percent of hydroxypropyl guanidine gum powder, 0.5 percent of KML-ZP cleanup additive, 0.1 percent of sodium carbonate, 1 percent of KML-YP organic boron crosslinking agent (Claritycor Meili chemical industry, Ltd.) +0.05 percent of ammonium persulfate
The fluid volume: 100m3
5. Pumping procedure
Circulating pressure test: the active water has a discharge capacity of 0.5-1m and a discharge capacity of 3-5m33/min
Secondly, planar seam net reconstruction: acid slick water 250m3Discharge capacity of 6m3/min
Tackified steering 40m3Discharge capacity of 6m370-100 mesh ceramsite 2m per min3
Conventional slickwater 210m3Discharge capacity of 6m3/min
Thirdly, artificial cracking: guanidine gum fracturing fluid 100m3 4m3
Fourthly, three-dimensional seam net reconstruction: acid slick water 150m3Discharge capacity of 6m3/min
Viscosity increasing and steering by 30m3Discharge capacity of 6m370-100 mesh ceramsite 1m per min3
Conventional slickwater 120m3Discharge capacity of 6m3/min
Fifthly, artificial crack sand filling: guanidine gum fracturing fluid 100m3Discharge capacity of 4m340 mesh/min ceramsite 25m3
Sixthly, displacement: activated water 16m3Discharge capacity of 3m3/min
Measuring pressure and reducing: measuring the pressure drop for 30min after the pump is stopped, and then open-blowing according to the requirements of test gas engineering
6. Capability of increasing the volume of the slotted net: alpha ═ beta + Vb/Va＝46.1％+300/500＝106.1％
In conclusion, the invention increases the capability of the fracture to continue to expand and extend forwards, can increase the extension pressure of the tail end of the peracid microcrack to a great extent, thereby increasing the extension length of the microcrack, and can maximally perform fracture network volume fracturing transformation around a perforation point, the acidic slickwater in the invention can solve the problems of rapid decrease of fracture conductivity, rapid decrease of post-fracturing yield and short effective period in the current complex oil-gas zone volume fracturing, furthest improves the long-term property of the fracture conductivity and the post-fracturing stable period, improves the fracturing transformation effect and the reservoir exploitation degree of the reservoir, and can save 10 to 30 percent of operating fluid if the volume transformation effect achieved by the conventional slickwater volume fracturing is analyzed from another angle, so the cost can be saved by using the acidic slickwater, the flowback of the fracturing fluid is also facilitated; the invention has the greatest highlight that the irregular elliptic body seam network volume fracturing effect with low thickness on the conventional plane is improved to the seam network volume fracturing effect with higher three-dimensional degree, so that a network crack system around a perforation point is more complex and developed, the fracturing effect is better than the seam network volume fracturing effect generated by using non-acid slickwater construction, and the reconstruction effect of the seam network volume near a shaft is maximized.
The technical characteristics form an embodiment of the invention, which has strong adaptability and implementation effect, and unnecessary technical characteristics can be increased or decreased according to actual needs to meet the requirements of different situations.
TABLE 1 Total well mineral analysis
TABLE 2 construction Scale of volume fracturing
TABLE 3 sour slickwater Performance index
Note: the beta is 310 (C%) +346 (C%)2(ii) a The well acidity C% is 13%.
Claims (22)
1. A method for increasing the volume fracturing effect of a complex oil and gas layer fracture network is characterized by comprising the following steps:
the method comprises the following steps of firstly, modifying a plane seam network, and alternately injecting non-acidic slick water and acidic slick water into a plane seam of a seam type reservoir stratum near a perforation point in sequence, wherein the acidic slick water comprises 5-25 parts of hydrochloric acid, 0-8 parts of hydrofluoric acid, 1-2 parts of corrosion inhibitor, 0.5-1 part of citric acid, 0.5-1 part of cleanup additive and 0.5-2.5 parts of resistance reducer, and the acidic slick water needs to meet the requirement that the corrosion inhibition rate is less than or equal to 0.5g/m2H, compared with clear water, the drag reduction rate is more than or equal to 40 percent, the viscosity of the acidic slickwater is less than or equal to 10mPa & s, and the surface tension is less than or equal to 25 mN/m; secondly, forming a tackified branch seam, tackifying the non-acidic slick water and the acidic slick water, and adding a propping and steering agent; thirdly, forming artificial cracks, injecting water-based fracturing fluid, and forming artificial cracks with the crack length of not less than 100 meters on two sides of a perforation point; fourthly, three-dimensional seam net reconstruction, namely injecting non-acidic slick water and acidic slick water alternately in sequence, performing seam net volume fracturing reconstruction on the wall surface of the artificial crack, tackifying the non-acidic slick water and the acidic slick water in a slug mode for at least three times, and adding a supporting steering agent; fifthly, filling sand in the artificial cracks; and sixthly, injecting displacement fluid, closing the well for a period of time, opening the well, discharging the fluid and producing oil gas.
2. The method of increasing the volumetric fracturing effect of complex hydrocarbon formations screens of claim 1, wherein the sour slickwater has a viscosity value of from 2 mPa-s to 8 mPa-s.
3. The method for increasing the volumetric fracturing effect of complex hydrocarbon formations screens of claim 1 or 2 wherein the corrosion inhibitor in sour slick water is an imidazoline type corrosion inhibitor; or/and the cleanup additive is a fluorocarbon type cleanup additive; or/and the resistance reducing agent is an acid-resistant resistance reducing agent which is formed by copolymerizing acrylamide monomers and other acid-resistant and salt-resistant monomers, and the molecular weight is between 600 and 1000 ten thousand.
4. The method for increasing the volume fracturing effect of the seam network of the complex oil and gas formation according to claim 1 or 2, characterized in that the addition amount of the hydrochloric acid and the hydrofluoric acid in the acid slick water is specifically as follows: when the content of acid-soluble mineral substances in the reservoir is 0-5% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 4 parts; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 2 parts; when the content of acid-soluble minerals in the reservoir is 25-50% and the main component of the acid-soluble minerals is calcite, the addition amount of hydrochloric acid is 15-25 parts and the addition amount of hydrofluoric acid is 1 part; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the addition amount of the hydrochloric acid is 15-25 parts, and the hydrofluoric acid is not added.
5. The method for increasing the volume fracturing effect of a complex hydrocarbon formation fracture network according to claim 3, wherein the addition amount of the hydrochloric acid and the hydrofluoric acid in the acid slick water is specifically as follows: when the content of acid-soluble mineral substances in the reservoir is 0-5% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 4 parts; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the adding amount of hydrochloric acid is 15-25 parts and the adding amount of hydrofluoric acid is 2 parts; when the content of acid-soluble minerals in the reservoir is 25-50% and the main component of the acid-soluble minerals is calcite, the addition amount of hydrochloric acid is 15-25 parts and the addition amount of hydrofluoric acid is 1 part; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the addition amount of the hydrochloric acid is 15-25 parts, and the hydrofluoric acid is not added.
6. The method for increasing the volume fracturing effect of complex hydrocarbon networks according to claim 1, 2 or 5, wherein in the first step and the fourth step, the matching relationship between sour slickwater and non-sour slickwater is as follows: when the content of the acid-soluble mineral substance in the reservoir is 0-5 percent and the main components of the acid-soluble mineral substance are clay and silicate, the injection amount of the acid slickwater is VGeneral assembly5% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the injection amount of the acidic slickwater is VGeneral assembly25% of red mark; when the content of acid-soluble mineral substances in the reservoir is 25-50% and the main component of the acid-soluble mineral substances is calcite, the injection amount of the acidic slickwater is VGeneral assembly50% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the injection amount of the acid slickwater is VGeneral assembly80% of the total weight; wherein, VGeneral assemblyIs the sum of the volume of sour and non-sour slick water.
7. The method for increasing the volume fracturing effect of a complex hydrocarbon formation fracture network according to claim 3, wherein in the first step and the fourth step, the matching relationship between the sour slickwater and the non-sour slickwater is as follows: when the content of the acid-soluble mineral substance in the reservoir is 0-5 percent and the main components of the acid-soluble mineral substance are clay and silicate, the injection amount of the acid slickwater is VGeneral assembly5% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the injection amount of the acidic slickwater is VGeneral assembly25% of red mark; when the content of acid-soluble minerals in the reservoir is 25-50 percent and the main component of the acid-soluble minerals is dissolvedWhen the stone is in place, the injection quantity of the acid slickwater is VGeneral assembly50% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the injection amount of the acid slickwater is VGeneral assembly80% of the total weight; wherein, VGeneral assemblyIs the sum of the volume of sour and non-sour slick water.
8. The method for increasing the volume fracturing effect of a complex hydrocarbon layer fracture network according to claim 4, wherein in the first step and the fourth step, the matching relationship between the sour slickwater and the non-sour slickwater is as follows: when the content of the acid-soluble mineral substance in the reservoir is 0-5 percent and the main components of the acid-soluble mineral substance are clay and silicate, the injection amount of the acid slickwater is VGeneral assembly5% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 5-25% and the main components of the acid-soluble mineral substances are clay and silicate, the injection amount of the acidic slickwater is VGeneral assembly25% of red mark; when the content of acid-soluble mineral substances in the reservoir is 25-50% and the main component of the acid-soluble mineral substances is calcite, the injection amount of the acidic slickwater is VGeneral assembly50% of the total weight; when the content of acid-soluble mineral substances in the reservoir is 50-80% and the main component of the acid-soluble mineral substances is limestone, the injection amount of the acid slickwater is VGeneral assembly80% of the total weight; wherein, VGeneral assemblyIs the sum of the volume of sour and non-sour slick water.
9. The method for increasing the volume fracturing effect of complex oil and gas layer fracture network according to claim 1 or 2 or 5 or 7 or 8, characterized in that in the first step, the construction displacement of acid liquor in acid slickwater is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the acid slick water and the non-acid slick water is not less than 5m3Min; or/and in the second step, the method for thickening the non-acidic slippery water and the acidic slippery water is to add 3 to 5 percent of alkyl quaternary ammonium salt, 0.5 to 2 percent of sodium benzoate and 1 to 3 percent of potassium chloride into the acidic slippery water and the non-acidic slippery water in the construction process to increase the viscosity of the acidic slippery water and the non-acidic slippery water to 5 to 15 mPa.s, wherein the alkyl quaternary ammonium salt is dodecyl ammonium chloride,More than one of tetradecyl ammonium chloride and gemini quaternary ammonium salt; or/and in the second step, the supporting diverting agent is ceramsite with 40 meshes to 70 meshes, and is added according to the proportion of 1 percent to 8 percent of the total amount of the non-acidic slick water and the acidic slick water; or/and, in the second step, the non-sour slick water and the sour slick water are tackified and added with a proppant diverting agent and added in the form of slugs; or/and in the fourth step, the construction discharge capacity of acid liquor in the acid slickwater is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the injected acidic slickwater and the non-acidic slickwater is at least 1.2 times of the discharge capacity of the injected acidic slickwater and the non-acidic slickwater in the first step; or/and in the fifth step, the artificial fracture sand filling is a guanidine gum fracturing fluid which comprises 0.35 to 0.5 part of hydroxypropyl guanidine gum powder, 0.5 to 3 parts of cleanup additive, 0.03 to 0.8 part of pH value regulator, 0.1 to 2 parts of organic boron crosslinking agent and 0.01 to 0.1 part of gel breaker, and the guanidine gum fracturing fluid needs to meet the following requirements: 170S at reservoir temperature-1The viscosity after shearing for 1 hour is more than or equal to 70 mPas, the surface tension of the broken guanidine gum fracturing fluid is less than or equal to 25mN/m, and the viscosity of the broken guanidine gum fracturing fluid is less than or equal to 5 mPas.
10. The method for increasing the volume fracturing effect of a complex hydrocarbon formation fracture network according to claim 3, wherein in the first step, the construction displacement of acid in the acid slickwater is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the acid slick water and the non-acid slick water is not less than 5m3Min; or/and in the second step, the method for tackifying the non-acidic slippery water and the acidic slippery water is to add 3 to 5 percent of alkyl quaternary ammonium salt, 0.5 to 2 percent of sodium benzoate and 1 to 3 percent of potassium chloride into the acidic slippery water and the non-acidic slippery water in the construction process, so that the viscosity of the acidic slippery water and the non-acidic slippery water is increased to 5 to 15mPa & s, wherein the alkyl quaternary ammonium salt is more than one of dodecyl ammonium chloride, tetradecyl ammonium chloride and gemini quaternary ammonium salt; or/and in the second step, the supporting and steering agent is ceramsite with 40 meshes to 70 meshes, and the total amount of the non-acidic slick water and the acidic slick water is 1 percent to 70 percentAdding 8 percent of the mixture; or/and, in the second step, the non-sour slick water and the sour slick water are tackified and added with a proppant diverting agent and added in the form of slugs; or/and in the fourth step, the construction discharge capacity of acid liquor in the acid slickwater is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the injected acidic slickwater and the non-acidic slickwater is at least 1.2 times of the discharge capacity of the injected acidic slickwater and the non-acidic slickwater in the first step; or/and in the fifth step, the artificial fracture sand filling is a guanidine gum fracturing fluid which comprises 0.35 to 0.5 part of hydroxypropyl guanidine gum powder, 0.5 to 3 parts of cleanup additive, 0.03 to 0.8 part of pH value regulator, 0.1 to 2 parts of organic boron crosslinking agent and 0.01 to 0.1 part of gel breaker, and the guanidine gum fracturing fluid needs to meet the following requirements: 170S at reservoir temperature-1The viscosity after shearing for 1 hour is more than or equal to 70 mPas, the surface tension of the broken guanidine gum fracturing fluid is less than or equal to 25mN/m, and the viscosity of the broken guanidine gum fracturing fluid is less than or equal to 5 mPas.
11. The method for increasing the volume fracturing effect of a complex hydrocarbon formation fracture network according to claim 4, wherein in the first step, the construction displacement of acid in the acid slickwater is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the acid slick water and the non-acid slick water is not less than 5m3Min; or/and in the second step, the method for tackifying the non-acidic slippery water and the acidic slippery water is to add 3 to 5 percent of alkyl quaternary ammonium salt, 0.5 to 2 percent of sodium benzoate and 1 to 3 percent of potassium chloride into the acidic slippery water and the non-acidic slippery water in the construction process, so that the viscosity of the acidic slippery water and the non-acidic slippery water is increased to 5 to 15mPa & s, wherein the alkyl quaternary ammonium salt is more than one of dodecyl ammonium chloride, tetradecyl ammonium chloride and gemini quaternary ammonium salt; or/and in the second step, the supporting diverting agent is ceramsite with 40 meshes to 70 meshes, and is added according to the proportion of 1 percent to 8 percent of the total amount of the non-acidic slick water and the acidic slick water; or/and, in the second step, the non-sour slick water and the sour slick water are tackified and added with a proppant diverting agent and added in the form of slugs; or/and, in the fourth step, is acidicThe construction discharge capacity of acid liquor in the slipway water is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the injected acidic slickwater and the non-acidic slickwater is at least 1.2 times of the discharge capacity of the injected acidic slickwater and the non-acidic slickwater in the first step; or/and in the fifth step, the artificial fracture sand filling is a guanidine gum fracturing fluid which comprises 0.35 to 0.5 part of hydroxypropyl guanidine gum powder, 0.5 to 3 parts of cleanup additive, 0.03 to 0.8 part of pH value regulator, 0.1 to 2 parts of organic boron crosslinking agent and 0.01 to 0.1 part of gel breaker, and the guanidine gum fracturing fluid needs to meet the following requirements: 170S at reservoir temperature-1The viscosity after shearing for 1 hour is more than or equal to 70 mPas, the surface tension of the broken guanidine gum fracturing fluid is less than or equal to 25mN/m, and the viscosity of the broken guanidine gum fracturing fluid is less than or equal to 5 mPas.
12. The method for increasing the volume fracturing effect of a complex hydrocarbon formation fracture network according to claim 6, wherein in the first step, the construction displacement of acid in the acid slickwater is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of the acid slick water and the non-acid slick water is not less than 5m3Min; or/and in the second step, the method for tackifying the non-acidic slippery water and the acidic slippery water is to add 3 to 5 percent of alkyl quaternary ammonium salt, 0.5 to 2 percent of sodium benzoate and 1 to 3 percent of potassium chloride into the acidic slippery water and the non-acidic slippery water in the construction process, so that the viscosity of the acidic slippery water and the non-acidic slippery water is increased to 5 to 15mPa & s, wherein the alkyl quaternary ammonium salt is more than one of dodecyl ammonium chloride, tetradecyl ammonium chloride and gemini quaternary ammonium salt; or/and in the second step, the supporting diverting agent is ceramsite with 40 meshes to 70 meshes, and is added according to the proportion of 1 percent to 8 percent of the total amount of the non-acidic slick water and the acidic slick water; or/and, in the second step, the non-sour slick water and the sour slick water are tackified and added with a proppant diverting agent and added in the form of slugs; or/and in the fourth step, the construction discharge capacity of acid liquor in the acid slickwater is 5m3Min to 12m3The acid solution is a mixed solution of hydrochloric acid and hydrofluoric acid, and the discharge capacity of acidic slickwater and non-acidic slickwater is filledAt least 1.2 times the displacement of the acidic and non-acidic skimming waters injected in the first step; or/and in the fifth step, the artificial fracture sand filling is a guanidine gum fracturing fluid which comprises 0.35 to 0.5 part of hydroxypropyl guanidine gum powder, 0.5 to 3 parts of cleanup additive, 0.03 to 0.8 part of pH value regulator, 0.1 to 2 parts of organic boron crosslinking agent and 0.01 to 0.1 part of gel breaker, and the guanidine gum fracturing fluid needs to meet the following requirements: 170S at reservoir temperature-1The viscosity after shearing for 1 hour is more than or equal to 70 mPas, the surface tension of the broken guanidine gum fracturing fluid is less than or equal to 25mN/m, and the viscosity of the broken guanidine gum fracturing fluid is less than or equal to 5 mPas.
13. The method for increasing the volume fracturing effect of complex oil and gas formations screens according to claim 1 or 2 or 5 or 7 or 8 or 10 or 11 or 12, characterized in that the non-acidic slickwater comprises 0.5 to 1 part of cleanup additive, 0.08 to 0.2 part of emulsion polyacrylamide with a molecular weight M of 500 to 900 ten thousand, and the non-acidic slickwater needs to satisfy: compared with clear water, the drag reduction rate is more than or equal to 60 percent, the viscosity is less than or equal to 10mPa & s, and the surface tension is less than or equal to 25 mN/m.
14. The method of increasing the volumetric fracturing effect of complex hydrocarbon fractures according to claim 3, wherein the non-acidic slickwater comprises 0.5 to 1 part of cleanup additive, 0.08 to 0.2 parts of emulsion polyacrylamide with a molecular weight M of 500 to 900 ten thousand, and the non-acidic slickwater is required to satisfy: compared with clear water, the drag reduction rate is more than or equal to 60 percent, the viscosity is less than or equal to 10mPa & s, and the surface tension is less than or equal to 25 mN/m.
15. The method of increasing the volumetric fracturing effect of complex hydrocarbon fractures according to claim 4, wherein the non-acidic slickwater comprises 0.5 to 1 part of cleanup additive, 0.08 to 0.2 parts of emulsion polyacrylamide with a molecular weight M of 500 to 900 ten thousand, and the non-acidic slickwater is required to satisfy: compared with clear water, the drag reduction rate is more than or equal to 60 percent, the viscosity is less than or equal to 10mPa & s, and the surface tension is less than or equal to 25 mN/m.
16. The method of increasing the volumetric fracturing effect of complex hydrocarbon fractures according to claim 6, wherein the non-acidic slickwater comprises 0.5 to 1 part of cleanup additive, 0.08 to 0.2 parts of emulsion polyacrylamide with a molecular weight M of 500 to 900 ten thousand, and the non-acidic slickwater is required to satisfy: compared with clear water, the drag reduction rate is more than or equal to 60 percent, the viscosity is less than or equal to 10mPa & s, and the surface tension is less than or equal to 25 mN/m.
17. The method of increasing the effectiveness of complex hydrocarbon network fracturing volume of claim 9 wherein the non-acidic slickwater comprises 0.5 to 1 part cleanup additive, 0.08 to 0.2 parts of an emulsion polyacrylamide having a molecular weight M of 500 to 900 ten thousand, and wherein the non-acidic slickwater is selected from the group consisting of: compared with clear water, the drag reduction rate is more than or equal to 60 percent, the viscosity is less than or equal to 10mPa & s, and the surface tension is less than or equal to 25 mN/m.
18. The method of increasing the volumetric fracturing effect of complex hydrocarbon formations screens of claim 13, wherein the non-acid slickwater is required to: the viscosity number is from 2 to 8 mPas.
19. The method of increasing the effectiveness of complex hydrocarbon fracture network volume fracturing of claims 14 or 15 or 16 or 17 wherein the non-sour slickwater is required to: the viscosity number is from 2 to 8 mPas.
20. The method of increasing the volumetric fracturing effect of complex hydrocarbon formations screens of claim 13 wherein the cleanup additive in the non-acidic slick water is a fluorocarbon type water-based fracturing cleanup additive.
21. The method for increasing the volumetric fracturing effect of complex hydrocarbon formations screens of claim 14 or 15 or 16 or 17 wherein the non-acidic slickwater cleanup additive is a fluorocarbon type water-based fracturing cleanup additive.
22. The method of increasing the volumetric fracturing effect of complex hydrocarbon formations screens of claim 19 wherein the cleanup aid in the non-acidic slick water is a fluorocarbon type water-based fracturing cleanup aid.
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| US20170306219A1 (en) * | 2016-04-22 | 2017-10-26 | Trican Well Service Ltd. | Controlled release of chemicals in oilfield operations |
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| CN104975840A (en) * | 2015-06-18 | 2015-10-14 | 中国石油化工股份有限公司 | Self-born acid composite acid fracturing process for high-temperature deep well carbonate rock reservoir |
| CN105349131A (en) * | 2015-09-29 | 2016-02-24 | 成都理工大学 | Shale gas reservoir deep transformation method based on acidic slickwater |
| CN106907137A (en) * | 2015-12-23 | 2017-06-30 | 中国石油化工股份有限公司 | A kind of method of the effective water conservancy diversion in shale oil reservoir volume fracturing crack |
| 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 |
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