CN116241226A - A kind of porous columnar fracturing method and its liquid support material and application - Google Patents

Abstract

The invention discloses a porous columnar fracturing method which is characterized in that in the fracturing process, an original solid phase propping agent is replaced by injecting a liquid phase propping agent, and the liquid phase propping agent is solidified to form a supporting material; the nano pore-forming agent which is uniformly dispersed is added into the liquid phase propping agent; according to the invention, through liquid injection, cracks which can be entered by fracturing can form supports, so that the problem of limited transportation capacity of a conventional propping agent is solved; the liquid phase support material provided by the invention has good portability, has lower requirement on fracturing fluid, and can be prepared into a fracturing fluid with wider solvent selection, wherein the fracturing fluid comprises one or more of tap water, well water, lake water, sea water, stratum water, produced water, fracturing flowback water and the like; compared with the conventional fracturing system, the using amount of the tackifier in the fracturing fluid is also greatly reduced.

Description

A kind of porous columnar fracturing method and its liquid support material and application

technical field

The invention belongs to the technical field of fracturing, and in particular relates to a porous columnar fracturing method, a liquid phase supporting material and its application.

Background technique

Hydraulic fracturing technology, as the main measure for oil and gas well stimulation and water well injection, has been widely used in the development of oil and gas fields. In hydraulic fracturing technology, proppant is one of the important materials. Its purpose is to support the fractures formed by fracturing, prevent fractures from closing, and provide channels for the flow of oil and gas, thereby improving the ability of fluids to pass through the formation. Various materials have been used as proppants during the development of hydraulic fracturing, such as quartz sand, metal aluminum balls, walnut shells, glass beads, ceramsite, etc. With the application of hydraulic fracturing technology becoming more and more mature, some deep and low permeability oil and gas reservoirs have been developed, and the requirements for proppant have also increased. The performance of proppant, such as sphericity, compressive strength, acid solubility And density etc. put forward higher requirements.

At present, the most widely used fracturing technology is the combination of conventional guar gum fracturing fluid system and sand fracturing. This technology generally has the following problems:

1) In order to improve the proppant portability of the fracturing fluid, high-viscosity fracturing fluid is often used to carry the proppant, but high-viscosity fracturing will cause higher damage to the formation and affect the fracturing effect;

2) It is superior to fracturing fluid in that the proppant has limited portability. It is usually difficult for proppant to enter the secondary and tertiary branch fractures far from the wellhead, and it is difficult for proppant to enter to form effective support;

3) The injection of solid proppant will cause certain wear and tear on the pipeline and the wellbore. At the same time, the sanding fracturing process is complicated. The high displacement and high pump pressure usually accompanied by high-concentration sanding have high requirements on the wellhead, construction equipment and construction string. , Improper control in the process of adding sand will also cause sand plugging, which is a potential large construction risk and personnel safety risk. Moreover, during the proppant injection process, due to factors such as high density and rigidity of the proppant, the proppant is often prone to sand-out, sand plugging, and failure to inject, so that the construction cannot achieve the expected effect, and even cause sand plugging in the wellbore.

4) The oil-gas circulation channel finally formed by conventional proppant is a small void in the proppant stack, which has poor permeability to oil-gas.

In recent years, most petroleum workers have devoted themselves to the research of low-density, high-strength solid-phase proppants, and obtained many gratifying results. However, regardless of the density of proppants, the solid-phase proppant However, there will still be problems such as difficult injection and difficult injection. Therefore, many researchers put forward the concept of liquid proppant. The principle is to replace the traditional solid proppant by injecting liquid proppant. After the liquid proppant is injected into the formation, due to the high-speed shear in the wellbore and the formation, small particles are formed. Then under the action of formation temperature, it solidifies to form proppant. This method avoids problems such as difficult injection and sand plugging in the process of using traditional solid proppants. However, the following problems still exist in its use:

1) The shearing effect during the injection process is uncontrollable, and the size of the formed particles is random;

2) When the injection process stops, the dispersed particles may gather again, and then directly block the formation.

3) In the end, the diversion channel is still the seepage space formed by the accumulation of small particles, and its diversion capacity to form propped fractures is still not much different from that of conventional proppants.

prior art 1

Patent CN 113322058 A introduces a phase-change proppant used in sea environment and its preparation method. The phase-change proppant includes: epoxy resin as the curing system, and phenalkamine epoxy resin curing agent is selected as the epoxy resin As a curing agent, 2-methylimidazole is used as a curing accelerator, nano-SiO2 is used as an emulsifier, and an aqueous solution of guar gum is used as an emulsion solvent.

Disadvantages of prior art 1:

This technology mainly forms solid-phase particles supporting the formation by emulsifying the formed resin particles, but the stability of the emulsified particles in the formation is uncertain. If stable emulsified particles cannot be formed in the high-temperature and high-pressure formation, it is easy to block the formation . At the same time, it is finally supported by solid phase particles, and resin particles are easy to soften under high temperature conditions, and the flow conductivity will be greatly reduced under the high closure pressure of the formation.

prior art 2

CN 105176513 B introduces a new type of ultra-low density proppant and its preparation method. The proppant is made from hydraulically active industrial waste mill as the main raw material and coated with resin. The invention provides a proppant with low density and high strength for oil and gas well fracturing technology.

Disadvantages of prior art 2

The proppant that can be formed by this method is the industrial waste slag after coating. Its support strength is limited, and its density is mainly determined by the industrial waste slag. If the proppant density is greatly reduced, a large amount of resin needs to be used, and the overall cost will increase. At the same time, the seepage channels of the final propped fractures are still voids formed by proppant accumulation, and its lifting effect is limited.

To sum up, there is a need for a liquid propped fracturing technology with high seepage channels and low construction risk.

Contents of the invention

In order to solve the above technical problems, the present invention provides a porous columnar fracturing method and its application.

In order to solve the above technical problems and achieve corresponding technical effects, the present invention is achieved through the following technical solutions: a porous columnar fracturing method, characterized in that, during the fracturing process, the original proppant is replaced by injecting a liquid phase proppant The solid phase proppant and the liquid phase proppant are solidified to form a support material;

Further, the nano-scale pore-forming agent uniformly dispersed in the liquid phase proppant is added;

After entering the formation, the nano-pore forming agent gasifies to form a liquid, dissolves part of the remaining solids, and forms a high-strength proppant material with micro-voids, providing high-strength channels for oil and gas seepage.

A liquid-phase support material for porous columnar fracturing, characterized in that it consists of a high-strength organic component A and a pore-forming material component B in a proportion of 100:1-20;

Among them, component A is mainly composed of the following materials: 180-210 parts of curable resin material, 1-3 parts of initiator system components, 10-20 parts of diluent, 2-10 parts of curing agent, and 1-5 parts of plasticizer 1-5 parts of other additives, 80-100 parts of water;

Component B is a pore-forming agent mainly composed of the following materials: 10-20 parts of gasified pore-forming components, 20-30 parts of liquefied pore-forming components and 30-50 parts of microparticle components with a mesh size of 200 or more;

Further, the curable resin material includes: novolak epoxy resin, polyimide resin, thermoplastic phenolic resin, thermoplastic urea-formaldehyde resin, melamine-formaldehyde resin;

Further, the initiator system components include: inorganic peroxide initiators or oxidation-reduction initiators, ammonium persulfate, sodium bisulfite, dicarbonate peroxide, cumene neodecanoate peroxide , Neodecanoic acid-2,4,4-trimethylpentyl peroxide, dibutyl peroxydicarbonate, dibutyl peroxide, tert-butyl peroxyisobutyrate, dilauroyl peroxide;

Further, the reactive diluent includes: ethylene glycol ether, monoepoxy reactive diluent, diepoxy reactive diluent, absolute ethanol, toluene, ethanol, acetone, butanol, dibutyl ester;

Further, the curing agent includes: phenalkamine epoxy resin, phenalkamine, hexamethylenetetramine, paraformaldehyde, glutaraldehyde, ammonium chloride, ammonium sulfate, ammonium nitrate;

Further, the plasticizer includes: dibutyl phthalate, octyl benzoate, polyester adipate;

Further, the other additives include: dimethylsiloxane, alcohol fat twelve;

Further, the gasification components include: urea, sodium bicarbonate, and sodium carbonate;

Further, the microparticle group includes: carbonate, silicate;

Further, the liquefied pore-forming component is a solid acid, and its preparation method is as follows:

(1) Stir or ultrasonically mix 30-60 parts of basic acid, 20-30 parts of polymerized monomer and 10-20 parts of solvent at room temperature to obtain a C1 mixed solution;

(2) Add 0.1-0.7 parts of initiator to the C1 mixed solution, and conduct a polymerization reaction at 40-65° C. for 3-6 hours to obtain a C2 reaction solution;

(3) drying the C2 reaction solution at 105-120° C. for 3-4 hours and granulating to obtain the granular solid acid; then grinding the solid acid into a powder of 300 mesh or more to obtain a powdery solid acid;

Further, the basic acid includes: hydrochloric acid, nitric acid, sulfuric acid, and hydrofluoric acid;

Further, the polymerized monomers include: styrene, sodium acrylate, acrylamide, epoxy ester and acrylate;

Further, the solvent includes: cyclohexane, ethanol, acetone, diesel oil, white oil;

Further, the initiator includes: azobisisobutyronitrile, dibenzoyl oxide, tert-butyl peroxybenzoate;

The beneficial effects of the present invention are:

1. Through liquid injection, the present invention can form supports for fractures that can be entered by fracturing, which solves the problem of limited transport capacity of conventional proppants;

2. The solidification time in the present invention is controllable, and by adjusting the formula of the raw material solution, a stable proppant solid phase can be obtained within 20 minutes to 3 hours;

3. The liquid-phase support material provided by the present invention has good portability, and has relatively low requirements for fracturing fluids. The preparation of fracturing fluids can have a wider selection of solvents, including tap water, well water, lake water, sea water, formation water, and produced water One or a combination of fracturing flowback water, etc.; compared with conventional fracturing systems, the amount of viscosifier in fracturing fluid is also greatly reduced.

4. The addition of the proppant formed by the present invention to the traditional material has a higher conductivity; the seepage channel of oil and gas is changed from the tiny gap between the traditional close-packed proppant to the large gap channel, which can greatly reduce the Oil and gas seepage resistance, thereby improving the effect of fracturing construction.

5. The present invention does not need to form stable particles in the formation, which can avoid the risk of clogging the formation.

Detailed ways

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the embodiments will be briefly introduced below.

Example 1

A porous columnar fracturing method, characterized in that during the fracturing process, the original solid-phase proppant is replaced by injecting a liquid phase, and when the liquid-phase proppant enters the formation, it will gradually solidify due to the increase in temperature, Form a high-strength proppant material, and in order to ensure that it has a seepage channel after curing, a nano-scale pore-forming agent will be added to the liquid, and the nano-scale pore-forming agent will be uniformly dispersed in the liquid proppant without affect its mobility. After entering the formation, the nano-pore forming agent will partially vaporize and partially form a liquid under high temperature conditions, and the formed liquid will also dissolve some of the remaining solids. Finally, under the action of the three, the formed high There are many micro-voids in the strong proppant material, which provide high-strength channels for oil and gas seepage.

Example 2

A liquid support material for porous columnar fracturing, its raw material is composed of high-strength organic component A and pore-forming material B component, the ratio of A and B components is 100:1-20, and A component is mainly composed of Composition of the following materials:

180-210 parts of curable resin material, 1-3 parts of initiator system components, 10-20 parts of diluent, 2-10 parts of curing agent, 1-5 parts of plasticizer, 1-5 parts of other additives, water 80-100 copies;

The curable resin material is one or a mixture of at least two of novolac epoxy resins, polyimide resins, thermoplastic phenolic resins, thermoplastic urea-formaldehyde resins, and melamine-formaldehyde resins;

Described initiator system component is inorganic peroxide initiator or oxidation-reduction type initiator, ammonium persulfate, sodium bisulfite, bis(2-ethylhexyl ester) of dicarbonate peroxide, new sunflower peroxide Cumyl peroxide, neodecanoic acid-2,4,4-trimethylpentyl peroxide, dibutyl peroxydicarbonate, bis(3,3,5-trimethylhexanoyl peroxide), peroxide One or more combinations of tert-butyl isobutyrate oxide and dilauroyl peroxide;

The reactive diluent is one or more of ethylene glycol ether, single epoxy reactive diluent, double epoxy reactive diluent, absolute alcohol, toluene, ethanol, acetone, butanol, dibutyl ester a combination;

The curing agent is one or at least two compounds of phenalkamine epoxy resin, phenalkamine, hexamethylenetetramine, paraformaldehyde, glutaraldehyde, ammonium chloride, ammonium sulfate, and ammonium nitrate;

Described plasticizer is one or more in dibutyl phthalate, octyl benzoate, adipate polyester;

The other additives described are dimethyl siloxane and alcohol fat twelve.

Component B is a pore-forming agent, which is mainly composed of three components: 10-20 parts of gasified pore-forming components, 20-30 parts of liquefied pore-forming components and 30-50 parts of microparticle components with a mesh size of 200 or more;

The gasification components described therein are: one or more of urea, sodium bicarbonate, and sodium carbonate;

The microparticle components are: one or more combinations of carbonates and silicates;

The liquefied pore-forming component is a solid acid. Its production method is as follows:

(1) Stir or ultrasonically mix 30-60 parts of basic acid, 20-30 parts of polymerized monomer and 10-20 parts of solvent at room temperature to obtain a C1 mixed solution;

(2) Add 0.1-0.7 parts of initiator to the C1 mixed solution, and conduct a polymerization reaction at 40-65° C. for 3-6 hours to obtain a C2 reaction solution;

(3) Drying the C2 reaction liquid at 105-120° C. for 3-4 hours and granulating to obtain the solid acid in granular form. Then grind the solid acid into a powder of more than 300 mesh. A powdery solid acid is obtained.

The basic acid in the above steps is one or more of hydrochloric acid, nitric acid, sulfuric acid, and hydrofluoric acid;

The above-mentioned polymerized monomer is one or more of styrene, sodium acrylate, acrylamide, epoxy ester and acrylate;

Above-mentioned solvent is one or more combinations in cyclohexane, ethanol, acetone, diesel oil, white oil;

The above-mentioned initiator is one or more of azobisisobutyronitrile, dibenzoyl oxide, and tert-butyl peroxybenzoate.

Example 3

Weigh 200 parts of curable resin material novolac epoxy resin, 1 part of ammonium persulfate, 20 parts of ethylene glycol ether, 5 parts of hexamethylenetetramine, 3 parts of dibutyl phthalate, 3 parts of dimethyl Silicone, 80 parts of water. Stir and mix at room temperature to obtain A solution.

Weigh 20 parts of urea, 20 parts of powdered solid acid and 50 parts of calcium carbonate components and mix uniformly to agent B.

The solid acid is to mix 60 parts of hydrochloric acid, 15 parts of sodium acrylate, 15 parts of acrylamide and 10-20 parts of cyclohexane ultrasonically at room temperature to obtain a C1 mixed solution; then add 0.2 parts of Azobisisobutyronitrile is then polymerized at 50° C. for 3 hours to obtain a C2 reaction solution; the C2 reaction solution is dried at 105° C. for 3 hours and granulated to obtain the solid acid in granular form. Then grind the solid acid into a powder of more than 300 mesh. A powdery solid acid is obtained.

Then weigh 100 parts of the solution, add 10 parts of B powder to it, and place the whole in an environment of 120° C. for 2 hours to obtain a high-strength material with interconnected voids.

Example 4

Unlike Example 2, 10 parts of urea, 10 parts of powdered solid acid and 30 parts of calcium carbonate were added in the B solution.

Example 5

The difference from Example 2 is that the curable resin added is 180 parts of polyimide resin, A and B are mixed and placed in an environment of 120°C for 0.5h.

The compression resistance of the honeycomb rod proppant obtained in the three implementation examples, porosity and interstitial connectivity are tested, and the test results are shown in the table below:

To sum up, 1. The present invention can form supports through liquid injection and fracturing into fractures, which solves the problem of limited transport capacity of conventional proppants;

2. The solidification time in the present invention is controllable, and by adjusting the formula of the raw material solution, a stable proppant solid phase can be obtained within 20 minutes to 3 hours;

3. The liquid-phase support material provided by the present invention has good portability, and has relatively low requirements for fracturing fluids. The preparation of fracturing fluids can have a wider selection of solvents, including tap water, well water, lake water, sea water, formation water, and produced water One or a combination of fracturing flowback water, etc.; compared with conventional fracturing systems, the amount of viscosifier in fracturing fluid is also greatly reduced.

4. The proppant formed by the present invention has a higher conductivity when added to traditional materials; the oil and gas seepage channel is changed from the gap between the traditional proppant to a large void channel, thereby greatly reducing the oil and gas seepage flow resistance, thereby improving the effect of fracturing construction.

5. The present invention does not need to form stable particles in the formation, which can avoid the risk of clogging the formation.

The preferred embodiments of the invention disclosed above are only to help illustrate the invention. The preferred embodiments are not exhaustive in all detail, nor are the inventions limited to specific embodiments described. Obviously, many modifications and variations can be made based on the contents of this specification. This description selects and specifically describes these embodiments in order to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. The invention is to be limited only by the claims, along with their full scope and equivalents.

Claims (8)

1. A method for porous columnar fracturing, characterized in that, in the process of fracturing, replacing the original solid proppant by injecting a liquid proppant, the liquid proppant is solidified to form a support material; A nano-scale pore-forming agent uniformly dispersed is added to the proppant. 2. A kind of liquid support material for porous columnar fracturing according to claim 1, characterized in that, the proportion of the components is 100:1-20 of the high-strength organic A component and the pore-forming material B component composition; Among them, component A is mainly composed of the following materials: 180-210 parts of curable resin material, 1-3 parts of initiator system components, 10-20 parts of diluent, 2-10 parts of curing agent, and 1-5 parts of plasticizer 1-5 parts of other additives, 80-100 parts of water; Component B is a pore-forming agent mainly composed of the following materials: 10-20 parts of gasified pore-forming components, 20-30 parts of liquefied pore-forming components and 30-50 parts of microparticle components with a mesh size above 200. 3. A liquid-phase support material for porous columnar fracturing according to claim 2, wherein the curable resin material comprises: novolac epoxy resin, polyimide resin, thermoplastic phenolic resin, thermoplastic urea-formaldehyde resin , melamine-formaldehyde resin; the initiator system components include: inorganic peroxide initiator or oxidation-reduction initiator, ammonium persulfate, sodium bisulfite, peroxydicarbonate, peroxynedecanoic acid iso Propylene glycol, neodecanoic acid-2,4,4-trimethylpentyl peroxide, dibutyl peroxydicarbonate, dibutyl peroxide, tert-butyl peroxyisobutyrate, dilauroyl peroxide; Said diluent includes: ethylene glycol ethyl ether, single epoxy reactive diluent, double epoxy reactive diluent, dehydrated alcohol, toluene, ethanol, acetone, butanol, dibutyl ester; said curing agent includes : Phenalkamine epoxy resin, phenalkamine, hexamethylenetetramine, paraformaldehyde, glutaraldehyde, ammonium chloride, ammonium sulfate, ammonium nitrate; the plasticizer includes: dibutyl phthalate , octyl benzoate, polyester adipate; said other additives include: dimethyl siloxane, alcohol fat twelve. 4. A kind of liquid support material for porous columnar fracturing according to claim 2, characterized in that, the gasified components include: urea, sodium bicarbonate, and sodium carbonate; the microparticle group includes: carbon salt, silicate. 5 . The liquid support material for porous columnar fracturing according to claim 2 , wherein the liquefied pore-forming component is a solid acid. 6. A kind of liquefied pore-forming component preparation method according to claim 2, is characterized in that, specifically comprises the following steps: S1. Stir or ultrasonically mix 30-60 parts of basic acid, 20-30 parts of polymerized monomer and 10-20 parts of solvent at room temperature to obtain a C1 mixed solution; S2. Add 0.1-0.7 parts of initiator to the C1 mixed solution, and conduct a polymerization reaction at 40-65° C. for 3-6 hours to obtain a C2 reaction solution; S3. Drying the C2 reaction solution at 105-120° C. for 3-4 h to obtain the granular solid acid; then grinding the solid acid into a powder with a mesh size of 300 or more to obtain a powdery solid acid. 7. A method for preparing liquefied pore-forming components according to claim 6, wherein the basic acid comprises: hydrochloric acid, nitric acid, sulfuric acid, and hydrofluoric acid; the polymerizable monomer comprises: styrene, Sodium acrylate, acrylamide, epoxy ester and acrylate; The solvent includes: cyclohexane, ethanol, acetone, diesel oil, white oil; The initiator includes: Azobisisobutyronitrile, dibenzoyl oxide, tert-butyl peroxybenzoate. 8. The liquid support material for porous columnar fracturing according to claims 1-7 is applied to pore column fracturing.