52results about How to "Improve fracturing effect" patented technology

The invention discloses a fracture diagnosis method and device, and belongs to the technical field of oil and gas reservoir fracture exploitation, and the diagnosis method comprises the steps: building a water hammer equation set through a water hammer continuity equation, a water hammer motion equation and a liquid elasticity equation; solving the water hammer equation set to obtain a distribution equation of the water head, the flow velocity and the density of the middle well section; initial conditions in the studied wellbore are determined, and expressions of water head, flow and density distribution are obtained in combination with the distribution equation; coupling the water hammer equation set with a wellhead flow boundary condition and a well bottom crack boundary condition, and calculating to obtain a water hammer pressure curve; and crack parameters are determined by adjusting crack related parameters in the well bottom crack boundary conditions. The device comprises a memory for storing a computer program and a processor, wherein the program comprises the steps corresponding to the method. According to the method, the related parameters of the fractures after fracturing are rapidly diagnosed based on the water hammer pressure in the fracturing process, a basis is provided for design and modification of an oil and gas resource reservoir transformation scheme, and therefore the fracturing transformation effect is improved.

The invention belongs to the field of petroleum and natural gas engineering, and discloses a hydrofracture optimization design method for controlling the fracture height of a deep coal bed gas reservoir and a related device. Establishing a three-dimensional fracture crossing numerical simulation model by using the modeling parameters; calculating the critical mechanical parameters and the critical bedding number of the roof rock and the floor rock of the target coal seam section by using the three-dimensional fracture crossing numerical simulation model; according to the calculated critical mechanical parameters of the top plate rock and the bottom plate rock, the actual mechanical parameters of the critical bedding number and the bedding number, whether the target coal seam section needs to be subjected to crack height control or not is judged; and when the target coal seam section needs to be subjected to fracture height control, performing fracture form simulation by utilizing the three-dimensional fracture crossing numerical simulation model to obtain a fracture construction parameter when the fracture height meets the requirement, and taking the fracture construction parameter as a final fracture construction parameter. The method can effectively control the crack height of the target coal seam section, and the single well production effect after fracturing is improved.

The invention provides a pump injection design method based on an effective support coefficient, and belongs to the technical field of oil and gas field development, and the method comprises the following steps: S1, based on a fluid-solid coupling theory, establishing a hydraulic fracture proppant migration equivalent model considering a bedding fracture; s2, with the optimal laying area as the target, the hydraulic fracture proppant migration equivalent model is used for simulating the proppant migration conditions under different parameter combinations, and an effective support coefficient is calculated; s3, based on the calculation result of the effective support coefficient, analyzing the change rule of the effective support coefficient under different parameters, and establishing a distribution pattern; and S4, on the basis of the distribution pattern, the pump injection process is optimized by utilizing the optimal range of the effective support coefficient. By means of the method, optimization of pumping key parameters such as displacement, sand ratio, sand adding particle size and particle size combination can be achieved, improvement of the overall flow conductivity of a shale oil reservoir fracturing fracture system is achieved, and therefore the fracturing effect is improved.

The invention relates to the technical field of oil production engineering, in particular to a fracturing process for a tight oil horizontal well, which comprises the following steps: acquiring geological data information; determining a rock stratum state according to the pore reference value of the to-be-constructed area and the tight oil enrichment degree, and determining a target stratum setting mode according to the rock stratum state; perforation is conducted on the toe end of the horizontal well, and fracturing operation is conducted on all target layers after perforation of the toe end of the horizontal well is completed; the injection amount of CO2 fracturing fluid is determined according to the length of the reference oil-containing sandstone, and the content of a thickening agent is determined according to the reservoir pressure; if the fracture density is smaller than the preset fracture density, it is determined that the fracturing fluid adjusting mode of the rear target layer is an optimization mode determined according to the gravel particle size difference degree or adjustment is conducted according to the injection pressure of CO2 fracturing fluid according to the gravel state of the proppant; after the CO2 fracturing fluid is injected into the whole well section, the well closing time is determined according to the comprehensive reference value; and drilling and removing the bridge plug. The fracturing effect can be improved, and the exploitation efficiency of the tight oil horizontal well is improved.

The invention relates to the technical field of thickening agents, in particular to a thickening agent for fracturing fluid and a preparation method of the thickening agent, the thickening agent comprises a liquid material and a solid material, the mass ratio of the liquid material to the solid material is 1: (2.2-2.4), and the liquid material is composed of deionized water and N-methyl pyrrolidone. According to the preparation method disclosed by the invention, the konjaku flour is added in the preparation of the thickening agent, and after the konjaku flour is subjected to mixing reaction and curing treatment, amino functional groups in konjaku molecules can be subjected to cross-linking reaction with aldehyde groups of glutaraldehyde, so that water molecules are wrapped in a cross-linked network structure, and the internal friction force during fluid flowing is increased; and hydroxyl groups on molecular chains of the konjac glucomannan and aldehyde groups of glutaraldehyde are subjected to a condensation reaction to form covalent bonds, so that a cross-linking effect is achieved, a stable chemical cross-linked network structure is formed among the molecular chains of the konjac glucomannan, and the cross-linking performance of the thickening agent is effectively improved.

A combustion improver continuous feeding method for methane in-situ burning explosion fracturing comprises the steps that a fracturing well section is determined, a well is drilled, and a drillable bridge plug is put in; assembling and installing a putting tool; the putting tool is put down, and the oil pipe through pipe and the shaft through pipe are connected in a sealed mode; high-pressure nitrogen is injected through nitrogen injection equipment, and the packer is set; a combustion improver is injected into the gas storage space of the throwing tool main body through the high-pressure hose by using oxygen injection equipment, and oxygen is injected into the sealed target section at a certain initial pressure; nitrogen with increased pressure is used for pushing a piston in the feeding tool main body downwards, so that the residual combustion improver in the gas storage space is discharged; the packing of the combustion improver is completed; finally, plugging the tool and performing compression ignition; according to the method, the continuous throwing of the methane in-situ burning explosion fracturing combustion improver and the packing technology of the combustion improver are combined, the packing problem of the combustion improver during the continuous throwing process of the combustion improver can be effectively solved, and the safety of the continuous conveying of the combustion improver along the way can be obviously improved.

The invention discloses a water hammer analogue simulation method and device for fracturing, and belongs to the technical field of oil and gas reservoir fracturing exploiting.The simulation method comprises the steps that a simulated shaft is determined; establishing a water hammer continuity equation and a water hammer motion equation based on the water head, the flow, the fluid density and the like; establishing a water hammer equation set by combining a liquid elastic equation combination, and solving to obtain a distribution equation of the water head, the flow velocity and the density; establishing a relational expression of fluid pressure, density and flow, and establishing a water hammer equation set in parallel to obtain a water hammer simulation model; initial conditions and boundary conditions are set, and a curve of water hammer pressure changing along with time is obtained through fitting. The device comprises a memory for storing a computer program and a processor, wherein the program comprises the steps corresponding to the method. According to the method, the water hammer pressure in the fracturing process can be more accurately simulated, developers are helped to analyze the fracturing effect by using the water hammer pressure in the fracturing process, so that fracturing parameters are optimized, a better fracturing effect is obtained, and efficient development of unconventional oil and gas resources is promoted.

The invention provides a tight sandstone discrimination and energy storage fracturing process parameter optimization method, which comprises the following steps: firstly, determining tight oil core physical properties and pore structure characteristics to lay a foundation for energy storage fracturing mechanism and scheme optimization, secondly, based on fracturing fluid imbibition and micro-macroscopic oil displacement tests, revealing a main action mechanism of imbibition, and finally, determining the energy storage fracturing process parameters according to the imbibition and micro-macroscopic oil displacement tests. Determining whether tight sandstone has imbibition, imbibition displacement oil displacement capability and imbibition displacement oil displacement mechanism; an oil-water replacement relational expression in the energy storage stage is established by analyzing data of shut-in time after pressure, the average daily pressure drop and the daily pressure drop in the open flow period; through tight oil fracturing productivity influence factor analysis, geological engineering key parameters influencing the tight oil energy storage volume fracturing effect are determined; an energy storage volume fracturing-productivity integrated analysis model is established, whether a tight reservoir needs energy storage or not and the energy storage mode are determined, applicable technical parameter boundaries are put forward, and theoretical and technical supports are provided for improving the energy storage volume fracturing effect and prolonging the effective period of measures.

The invention relates to the technical field of oil and gas field yield increase and transformation, in particular to a tight reservoir vertical well group fracturing optimization design method which comprises the following steps: collecting geological data and engineering data of a fracturing target block; a vertical well fracturing crack stress disturbance mathematical model is established, and reservoir disturbance stress distribution is simulated; establishing a crack support crack width attenuation mathematical model, and simulating a change rule of the support crack width along with time; combining engineering data with the stress disturbance mathematical model to determine a well group combination mode and a multi-well fracturing sequence of vertical well group fracturing; and based on the result of the fourth step, the fracturing time interval between the vertical wells in the well group is designed by combining the supporting seam width attenuation mathematical model. According to the method, the problems of well group combination mode, multi-well fracturing sequence, fracturing time interval and the like during tight reservoir vertical well group fracturing construction design are effectively solved, steering extension of fracturing cracks is achieved, the fracturing transformation effect of a reservoir is improved, and therefore the oil and gas yield of a single well is increased.

The invention provides a method for controlling multi-scale fracture extension at different positions of a main fracture and a fracturing method, and belongs to the field of oil and gas exploitation, the method comprises the steps that fracturing fluid is injected to conduct segmented fracture forming construction on the main fracture, and each fracture forming stage expands to generate the main fracture with the preset length; temporarily plugging the end part of the main crack by adopting a temporary plugging agent, and opening the multi-scale crack in the length direction of the main crack through a temporary plugging effect; a propping agent is continuously injected to fill the multi-scale crack; the blocking of the end of the main crack is relieved, the process from the main crack segmented crack forming construction to the multi-scale crack filling is repeated till the crack length of the main crack reaches the maximum value, and a multi-scale crack network is formed in the length direction of the main crack; and a proppant is continuously injected to fill the main crack. According to the fracturing method provided by the invention, the main crack and the branch cracks can be fully extended, and effective support of the main crack and the branch cracks is ensured.

The present invention relates to the field of fracturing fluid, and in particular to an emulsion-modified fracturing fluid for oil well protection and a preparation method thereof, which is used to solve the problem that although a conventional fracturing fluid can increase oil well production, it is easily ineffective in a high-temperature and high-pressure oil well environment, which not only affects the fracturing effect, but may also cause damage to the oil well, resulting in a poor oil well protection effect; the fracturing fluid has high temperature resistance and salt resistance, so that it can work stably in a high-temperature oil well, and has excellent viscosity, can effectively carry sand during the fracturing process, form stable cracks, is conducive to the effective exploitation of oil and gas resources, can maximize its advantages in oil well protection and production increase, and its preparation method is simple, the cost is low, it is easy to industrialize production, and has broad application prospects.

The invention discloses a method for preparing a self-flowing high-efficiency fast-dissolving drag-reducing fracturing fluid system. The following components in weight percentage are added into a reactor in sequence: 45% to 50% of the water-soluble high molecular polymer solution obtained in step one, 27% to 29% of the fluorine-containing monomer modifier solution obtained in step two, 11% to 12% of the polymer nanocomposite material obtained in step four, 2% to 3% of a dispersant, 1.8% to 1.9% of an inorganic salt, 1.2% to 1.3% of a cross-linking agent, and the balance is water. The invention discloses a method for preparing a self-flowing high-efficiency fast-dissolving drag-reducing fracturing fluid system. By adding a modifier into a nano material, a polymer film can be directly formed on the surface of the nano material by chemical bonding, thereby changing the surface properties thereof, so that the stability and shear resistance of the fracturing fluid are maintained at high temperatures.

The invention provides a biodegradable ammonium persulfate coating gel breaker for fracturing operation and a preparation method of the biodegradable ammonium persulfate coating gel breaker. The preparation method comprises the following steps: determining a mass ratio R of rosin glyceride to ethyl cellulose according to a target reservoir temperature T, and calculating a coating weight gain ratio coefficient K and the total mass of a coating material according to target delayed gel breaking time t; preparing a core material ammonium persulfate into a water phase, and emulsifying in an oil phase to form a reversed-phase microemulsion; a gradient interface deposition method is adopted, a coating solution A prepared from rosin glyceride and part of ethyl cellulose and a coating solution B prepared from the remaining ethyl cellulose are dropwise added in sequence, and a coating material is sequentially deposited on a core material liquid drop interface through pressure reduction to form a compact bottom layer and a slow-release main body layer; according to the invention, the coating layer is biodegradable, chlorine-free and corrosion-free, through the cooperation of the material ratio and the process, the accurate and controllable delay of the gel breaking time at high temperature is realized, the reservoir is effectively protected, and the fracturing effect is improved.

This invention relates to a zero-residue multi-stage deflagration fracturing method and system, addressing the problems of existing deflagration fracturing devices, such as well-water pollution, failure to achieve the expected fracturing effect, and low efficiency. The multi-stage deflagration fracturing method includes: Step 1: Preparing the deflagration fracturing charge, central tube, and guide plug in the deflagration fracturing system using a combustible material that is soluble in chloride ions; Step 2: During operation of the deflagration fracturing system, a detonator ignites the central tube and the deflagration fracturing charge; Step 3: The central tube burns, the deflagration fracturing charge deflagrates, and the guide plug burns simultaneously, thus performing multi-stage deflagration fracturing; Step 4: After deflagration fracturing is completed, the residue from the central tube, deflagration fracturing charge, and guide plug falls into the well water, where it dissolves completely, achieving zero residue. To achieve the above method, this invention also proposes two zero-residue multi-stage deflagration fracturing systems.

The invention belongs to the technical field of coal mine drilling tool equipment, and particularly provides a drilling, fracturing and hole protecting integrated drill bit which comprises a connecting rod section and a drill bit section, one end of the connecting rod section is connected with an external drill rod, the drill bit section is assembled at the other end of the connecting rod section, the drill bit section is divided into an inner layer and an outer layer, and a gap is reserved between the inner layer and the outer layer. An annular screen pipe moving power valve is arranged in the gap, a water outlet is formed in the end face of the drill bit section, and an inner sleeve is arranged in the connecting rod section. Drilling, fracturing and hole protection are integrated, after drilling construction is completed, in-hole real-time machining, hole protection screen pipe lowering and fixed-point multi-load fracturing are carried out from the bottom of a hole to the outside of the hole, the problem of hole collapse caused by drill withdrawal is solved, the protection pipe lowering rate is increased, the drilling fracturing precision is improved, the fracturing effect is enhanced, and the drilling gas extraction effect is greatly improved.

The invention discloses a heat-resistant and salt-resistant nano-fracturing imbibition agent and a preparation method thereof, and belongs to the technical field of oil and gas exploitation. A heat-resistant and salt-resistant nano-fracturing imbibition agent is composed of the following components: starch, acrylic acid, ammonium persulfate, sodium bisulfite, quaternary ammonium salt, interfacial tension reducer, and deionized water. The heat-resistant and salt-resistant nano-fracturing imbibition agent provided by the invention has a hydrophobic associating polymer and an interfacial tension reducer as the main components, and has excellent heat resistance, salt resistance, and shear resistance; the formation adsorption loss is small, the oil-water interfacial tension is low, and it can penetrate into the deep part of the low-permeability reservoir, change the wettability of the rock, and through a certain period of well sealing after fracturing, the surfactant is absorbed into the pore throat of the ultra-low permeability reservoir, and more crude oil is absorbed and replaced, thereby improving the fracturing effect of the tight oil layer, delaying the production decline rate, and improving the single well production and recovery rate; the raw materials are widely available, the cost is low, the method is simple and easy to operate, and it is suitable for industrial production.

The utility model relates to the technical field of mining, and provides a rock stratum drilling cutterhead and a drilling assembly, the rock stratum drilling cutterhead comprises a cutterhead main body, a cutter assembly, a center pre-crushing assembly and an edge pre-crushing assembly; the center pre-crushing assembly is used for pressing a rock stratum located in the center of the cutter head body so that the rock stratum in the center can be fractured. The edge pre-crushing assembly is used for pressing a rock stratum at the edge which is located in the cutter head main body and located outside the center, so that the rock stratum at the edge is fractured, and a fracturing crack of the rock stratum at the edge is connected or crossed with a fracturing crack of the rock stratum at the center; and the cutter assembly rotates to cut the fractured rock stratum. According to the utility model, the center pre-crushing assembly and the edge pre-crushing assembly can be used for fracturing rocks at axial frequency, so that the structural strength and rigidity of the rocks cut by the cutter assembly are dynamically reduced in real time, the tunneling efficiency is improved, and the tunneling difficulty is reduced.

The invention belongs to the technical field of oil and gas field development reservoir transformation, and discloses a tracer agent for multilayer fracturing flowback monitoring, a preparation method and application, according to the preparation method, the effectiveness of the tracer agent is evaluated through an experimental means, and it is guaranteed that the effective tracer agent can be used for monitoring a flowback curve of fracturing fluid flowback volume along with time; according to the application method, a tracer agent is used for marking fracturing fluid, and the initial fracturing fluid dosage and the initial tracer agent dosage are recorded; after flowback is started, accumulated flowback volume is recorded at a fixed time interval, the real-time concentration of the tracer agent is measured, and the flowback volume of each section is calculated; according to the return volume of each section and the accumulated return volume of each section, the return curve and the accumulated return rate of each section are calculated, the liquid production contribution rate and the production sequence of each layer section can be accurately obtained, and the liquid production capacity can be calculated in a semi-quantitative mode. Through flow-back liquid sample detection and data analysis, the liquid drainage sequence, the flow-back contribution rate and the like of each layer section can be determined, and data support is provided for subsequent construction.

The invention belongs to the technical field of oil exploitation, and particularly relates to a dry powder thickening agent for fracturing as well as a preparation method and application thereof. The thickening agent comprises the following components: (a) 1-vinyl-2-pyrrolidone; (b) a di [2-(methacryloyloxy) ethyl] phosphate ester; (c) 2-(perfluorohexyl) ethyl methacrylate; (d) 4, 4 '-diaminostilbene-2, 2'-disulfonic acid; (e) an initiator; based on 1 mole part of 1-vinyl-2-pyrrolidone, the dosages of the di [2-(methacryloyloxy) ethyl] phosphate ester, the 2-(perfluorohexyl) ethyl methacrylate and the 4, 4 '-diaminostilbene-2, 2'-disulfonic acid are 0.05 to 0.1 mole part, 0.1 to 1 mole part and 0.2 to 0.5 mole part respectively, and the dosages of the di [2-(methacryloyloxy) ethyl] phosphate ester, the 2-(perfluorohexyl) ethyl methacrylate and the 4, 4 '-diaminostilbene-2, 2'-disulfonic acid are respectively 0.05 to 0.1 mole part, 0.1 to 1 mole part and 0.2 to 0.5 mole part. The thickening agent has the advantages of high apparent viscosity, high shear resistance, temperature resistance and high resistance reduction rate, and the resistance reduction rate reaches 70% or above.

The present invention discloses a method, system, equipment and medium for designing infill well fracturing based on available areas, and belongs to the technical field of unconventional natural gas exploration and development. The method comprises the following steps: S1: establishing an infill well fracturing parameter design model for a target block; S2: simulating the production process of an implemented well network to obtain the pressure field before infill well fracturing; S3: carrying out four-dimensional stress dynamic calculation in the process of oil and gas reservoir exploitation to obtain stress evolution results, and updating relevant geological parameters in the model according to the stress evolution results; S4: identifying the available area of ​​the infill well in the updated infill well fracturing parameter design model; S5: classifying the fracturing sections of the infill well according to the available area of ​​the infill well, and designing differentiated fracturing construction parameters for each level of fracturing sections after classification. The present invention can carry out a more sophisticated differentiated fracturing design for infill wells, while improving the fracturing effect of infill wells and avoiding pressure channeling, thereby increasing the overall production capacity of the infill well group.

A method for strengthening methane in-situ combustion fracturing, liquid carbon dioxide is pressurized and heated to form supercritical carbon dioxide, which is then sent into the fracturing channel to form a complex fracture network around the fracturing channel; mixed fracturing fluid formed by mixing supercritical carbon dioxide and fly ash is injected into the well bottom; combustion-supporting agent is injected into the wellbore and mixed with the mixed fracturing fluid at the well bottom to enter the complex fracture network together, so that a multiphase mixed fluid is formed in the complex fracture network; the annulus valve is closed to promote mineralization reaction of supercritical carbon dioxide and fly ash under the temperature and pressure conditions of the reservoir, and to form high-strength minerals; the mineralization reaction is used to promote the desorption of methane in the reservoir and into the complex fracture network, so that methane-combustion-supporting agent mixed gas is formed in the complex fracture network; the combustion process is used to promote the dust cloud formed by the mixing of fly ash and gas in the complex fracture network, to strengthen the effect of methane in-situ combustion; and the fracturing reconstruction of all layers is completed. The fracturing effect of the method is ideal.

The invention discloses a gas reservoir fracturing fluid rock modification system as well as a preparation method and application thereof, and belongs to the technical field of oil and gas reservoir fracturing fluids. The gas reservoir fracturing fluid rock modification system provided by the invention is prepared from the following raw materials in percentage by volume: 0.001 to 0.2 percent of rock modifier, 0.1 percent of cosolvent, 10 percent of mutual solvent, 0.1 percent of glacial acetic acid, 2 percent of cross-linking agent and the balance of water. According to the gas reservoir fracturing fluid rock modification system, hydroxyl groups on the surface of rock can be replaced by strong hydrophobic groups, the wetting angle of a rock interface to water is increased, and the flow-back efficiency of the gas reservoir fracturing fluid is greatly improved.

The invention relates to a microseism event point separation method and system based on logging constraint, and the method comprises the steps: analyzing curve energy differentiation characteristics through logging data, and calculating a crack strength curve; extracting the energy level, depth and spatial position of the microseism event, and determining the three-dimensional distribution characteristics of the microseism event; constructing a fracture network form based on the time sequence and the spatial position of the microseism event; then, interactive analysis is carried out on the microseismic event B value and the logging crack strength, and energy compensation is carried out on the microseismic energy level; primary and secondary cracks are distinguished according to the energy conservation principle of fracturing fluid; and evaluating a power law relationship between the number of the microseism events and the magnitude to form systematic statistical analysis. According to the method, by combining logging information and a microseism monitoring technology, the problem of energy attenuation in a traditional method is effectively solved, the reliability and precision of microseism event separation are improved, a scientific basis is provided for fracturing construction, and efficient development of oil and gas resources is promoted.

The application discloses a device for strengthening fracturing of a ground drilling well and a method for determining fracturing conditions, which comprises the following steps: firstly, after the ground drilling well passes through a coal seam, a bottom space of the drilling well is formed by continuous construction, and an air bag is arranged in the bottom space of the drilling well, which is used for avoiding that acid and alkali liquid enters the bottom space of the drilling well when fracturing, and after the fracturing is completed, the acid and alkali liquid is discharged into a lower rock layer under the bottom space of the drilling well; secondly, acid liquid and alkali liquid are alternately injected into the ground drilling well to perform fracturing impact; thirdly, the functions of dissolving and dissolving and corroding cementing material, mineral and blockage in the coal body by the acid liquid and the alkali liquid are used to improve fracturing effect; and fourthly, after the acid liquid is fractured, a positioning support ball is carried into a crack to perform support, and the positioning support ball can delay the closure of the crack and can move when the alkali liquid is fractured. After the fracturing is completed, the positioning support ball is distributed in the crack, the positions of the positioning support balls in the coal seam can be obtained by using a positioner detector, and then the development and cracking conditions of the crack after the fracturing can be obtained, so that the arrangement position of the next ground drilling well can be determined.

The invention relates to the technical field of oil and gas field exploration and development equipment, and discloses a single-gun-body in-situ rotary bullet-changing in-situ different-item perforator and an operation method thereof.The perforator comprises a shell, an annular cavity is formed in the shell, multiple pairs of through holes are oppositely formed in the two side walls of the annular cavity, and each pair of through holes are longitudinally formed; the two bullet supply parts are oppositely arranged on the shell, the rotary driving part is connected with the two bullet supply parts, and each bullet supply part is provided with a plurality of bullet storage bins corresponding to the second through holes, perforating bullets arranged in the bullet storage bins and a push-out part; the plurality of piezoelectric micro-valve modules are respectively arranged at the opposite through holes in the annular cavity and are used for controlling the opening degree of the valve; the control system is in signal connection with the rotary driving part, the plurality of push-out parts and the plurality of piezoelectric micro-valve modules; the perforator is simple in design and free of downhole fallen objects, double dynamic adjustment of variable energy and secondary phase can be achieved through a single tubular column, and the perforation efficiency and the reservoir transformation effect are remarkably improved.

The invention provides a biologically modified fracturing propping agent as well as a preparation method and application thereof, and belongs to the technical field of oil gas yield increase and transformation. A biological material sodium alginate-calcium gel is used as a shell, environment friendliness and low cost are achieved, the propping agent is carried by fracturing fluid to enter a far-end rock stratum crack through the hydrophilicity of the propping agent, in the well shut-in process, high temperature and ground stress enable the sodium alginate-calcium gel shell to be broken, internal slurry is exposed, and the fracturing effect is achieved. The proppant in the slurry can be adhered and fixed on the crack wall under the coating of the high-viscosity sodium alginate aqueous solution, so that the migration of the proppant in the backflow process of the fracturing fluid is reduced or slowed down; meanwhile, the surface of the proppant is coated with the sodium alginate aqueous solution, so that ground stress can be buffered, the proppant is prevented from being broken, accumulation and blockage of the proppant are reduced, the supporting efficiency of the proppant is improved, and the fracturing effect is improved.

The invention discloses a tight sandstone gas reservoir horizontal well section compressibility rapid evaluation method, which comprises the following steps: (1) establishing a three-dimensional reservoir quality model, and obtaining the reservoir quality category of a horizontal well section; (2) constructing a brittleness index model of adjacent vertical well mineral components; (3) obtaining the brittleness index of the well section of the horizontal well; and (IV) integrating the reservoir types of the horizontal well section and the normalized brittleness index to form a compressibility rapid evaluation chart, and rapidly dividing compressibility types of the horizontal well section. According to the method, the reservoir quality type and the brittleness index of the horizontal well section are obtained on the basis of the relation among the adjacent vertical well productivity, the mineral component experiment and the natural gamma logging curve, the compressibility rapid evaluation chart is formed, and reference is provided for horizontal well rapid fracturing segmented optimization and fracturing effect improvement.

The invention discloses a compact rock fracturing device and method based on CO2 phase state change. The compact rock fracturing device comprises a compact rock sample with a central through hole, and further comprises an injection module configured to inject fluid into the compact rock sample; the upper sealing assembly and the lower sealing pipe fitting are both arranged in the center through hole, the upper sealing assembly and the lower sealing pipe fitting are oppositely arranged, an open hole section is defined by the upper sealing assembly, the lower sealing pipe fitting and the center through hole, and fluid is injected into the open hole section; the temperature control module comprises a cold control unit and a thermal control unit, and the cold control unit and the thermal control unit are communicated into the open hole section; and the fluid monitoring module is used for monitoring the pressure and temperature of the fluid in the naked eye section. The fluid temperature and pressure alternating effect can degrade the mechanical property of the compact rock sample; the fluid phase state change induces the generation of dominant fracturing fractures, and the two synergistically act to achieve the purpose of strengthening the reconstruction of the compact rock sample.

This invention discloses a sterically hindered hydrophilic nano-silica, its preparation method, and its applications, belonging to the field of shale oil and gas storage modification and production enhancement technology. The sterically hindered hydrophilic nano-silica is modified with ethylene oxide and aniline. The nano-silica has a particle size of 2-5 nm, the mass percentage of ethylene oxide to nano-silica is 1.5-3:1, and the mass percentage of aniline to nano-silica is 0.8-3:1. The prepared hydrophilic nano-silica can be used in the preparation of reagents to reduce fracturing fluid damage. This hydrophilic nano-silica competes with polymers for adsorption, reducing polymer adsorption blockage and thus reducing fracture damage.

The invention provides a three-dimensional well pattern collaborative fracturing simulation method, and relates to the technical field of oil and gas development, and the method comprises the steps: obtaining basic parameters of a target reservoir, so as to establish a three-dimensional well pattern collaborative fracturing model; endowing the basic parameters to a structured fracture grid unit in the three-dimensional network collaborative fracturing model, and obtaining the length and the fracture propagation speed of the fracture grid unit to determine a corresponding simulation time step length; in each simulation time step length, performing fracturing numerical simulation on the fracturing section of the fracturing well in each well section; after it is determined that all the well sections of the three-dimensional well pattern complete numerical simulation, fracturing simulation results of all the well sections in the three-dimensional well pattern are output, and the fracturing simulation results comprise the fracture expansion form, the proppant laying form, the reservoir transformation volume, the effective reservoir transformation volume and fracturing induced stress field distribution. According to the method provided by the invention, the technical effect of improving the collaborative fracturing efficiency of the three-dimensional well pattern is achieved.