Abstract: The present invention pertains to the field of oilfield stimulation technologies for oil and gas field development, in particular to an instant soluble temperature and salt resistant polyacrylamide and the preparation method and application thereof, and the polyacrylamide is modified by adding rigid temperature and salt resistant monomer containing benzene ring and cationic fluorinated hydrophobic monomer on the basis of acrylamide monomer and sodium acrylate monomer, and then polymerized to obtain instant soluble temperature and salt resistant polyacrylamide. The temperature and salt resistant monomer containing benzene ring can improve the thermal stability and temperature and salt resistance of polyacrylamide, while the long-chain cationic fluorinated hydrophobic monomer can enhance the hydrophobicity of polymer. The comprehensive properties of polymer is improved by appropriate intermolecular association.

Abstract: The present invention discloses a novel high-temperature visual acid etching test device and method; the test device includes a visual rock slab holder, an acid solution storage tank I, an acid solution storage tank II, a heating apparatus, a high-pressure water pump, a low-pressure acid pump, a back-pressure valve, an acid valve A, an acid valve B, an acid valve C, an acid valve D, an acid valve E, an acid valve F, a water valve G, a water valve H, a water valve I, a water valve J, and a water valve K; both the acid solution storage tank I and the acid solution storage tank II are provided with a piston therein, where the acid solution storage tank is divided into upper and lower independent parts by the piston. According to the present invention, the flowing process of an acid solution in a fracture can be directly observed to accurately characterize the distribution of the acid solution in the fracture, which facilitates a study on an acid etching mechanism.

Abstract: A calculation system for predicting a proppant embedding depth based on a shale softening effect is provided, including a sampling test terminal, a scheduling module, a monitoring module, and a calculation module, wherein the scheduling module, the monitoring module, and the calculation module are connected in communication, and the monitoring module is connected to an external operating system through a wireless network, wherein the external operating system is configured to perform a hydraulic fracturing operation and receive a first control signal and/or a second control signal from the monitoring module. The sampling test terminal is configured to test the samples and obtain test data. The scheduling module is configured to determine a target construction parameter.

Abstract: The present invention relates to a three-dimensional acid fracturing method for carbonate reservoirs in long intervals, which sequentially comprises the following steps: S1: based on the distribution characteristics of porosity and permeability of the reservoir where the candidate well is located, the reservoirs are divided into Class I, Class II and Class III, and the required acid fracturing fracture density range ?ir of different types of reservoirs is determined according to the increase of production; S2: Determine the most economical fracture number Ne when the economic net present value NPV of candidate wells reaches the maximum in the fifth year based on interval length of different types of reservoirs in candidate wells and acid fracturing fracture density range ?ir determined by S1; S3: Determine the three-dimensional acid fracturing segmented fracture arrangement technology according to the completion mode of the candidate well and the most economical fracture number Ne determined by S2; S4: Based

Abstract: A structural stabilizer for a fiber and proppant complex to enhance proppant migration and placement in a fractured well during propping and a preparation method thereof are provided. The structural stabilizer consists of: water, inorganic salt, kaolinite, nitrogen-doped modified graphene oxide, anionic surfactant, non-ionic alkyl polyglucoside, and polyacrylamide. The structural stabilizer improves bonding between a proppant and a fiber when slick water is used in stimulated reservoir volume (SRV) fracturing, prevents separation of the fiber and the proppant during migration, thereby reducing escape rate of the fiber from the fiber and proppant complex.

Abstract: A soluble metal sealing ring with a controllable dissolution rate and preparation process thereof include an aluminum alloy sealing ring matrix and a composite coating coated on an outer surface of the aluminum alloy sealing ring matrix whose standard electrode potential is greater than ?0.3 volts (V). The preparation process includes: (1) preparing a high-plastic aluminum alloy; (2) preparing the aluminum alloy sealing ring matrix by machining; (3) annealing the aluminum alloy sealing ring matrix; (4) mixing raw materials of the composite coating evenly; (5) preparing the composite coating on an outer surface of the aluminum alloy sealing ring matrix; (6) preparing holes. The soluble metal sealing ring solves problem that good sealing performance and good dissolving performance are difficult to obtain simultaneously in the existing product, and has advantages of good sealing performance, controllable dissolving rate, no blockage and others.

Abstract: The present disclosure relates to a calculation method for predicting a proppant embedding depth based on a shale softening effect, including determining a spontaneous imbibition depth-soaking time curve; determining a Young’s modulus-soaking time curve of core surfaces; establishing a proppant embedding model containing a softened layer by a finite element method; conducting a numerical simulation to obtain an embedding volume-soaking time curve; and obtaining a calculation formula for a proppant embedding volume considering a softening effect.

Abstract: A soluble metal sealing ring with a controllable dissolution rate and preparation process thereof include an aluminum alloy sealing ring matrix and a composite coating coated on an outer surface of the aluminum alloy sealing ring matrix whose standard electrode potential is greater than -0.3 volts (V). The preparation process includes: (1) preparing a high-plastic aluminum alloy; (2) preparing the aluminum alloy sealing ring matrix by machining; (3) annealing the aluminum alloy sealing ring matrix; (4) mixing raw materials of the composite coating evenly; (5) preparing the composite coating on an outer surface of the aluminum alloy sealing ring matrix; (6) preparing holes. The soluble metal sealing ring solves problem that good sealing performance and good dissolving performance are difficult to obtain simultaneously in the existing product, and has advantages of good sealing performance, controllable dissolving rate, no blockage and others.

Abstract: A method for characterizing complexity of rock fracture based on fractal dimension and a device thereof are provided. The method includes steps of: collecting rock fracture samples of a rock, and collecting basic parameters of the rock; determining a fractal dimension of a rock fracture morphology of the rock; calculating the fractal dimension of the rock; calculating a complexity coefficient Fc of rock fracture of the rock; and characterizing a complexity of rock fracture of the rock based on the complexity coefficient Fc of rock fracture of the rock. In the present invention, combined with the fractal geometry theory, fracture complexity coefficient of shale rocks is redefined and calculated to accurately characterize rock fracture morphology, so that characteristics of rock fracture morphology is correctly understood and affecting factors of fracture morphology is analyzed.

Abstract: The present invention discloses a numerical simulation method for proppant transport considering wall-retardation effect, comprising the followings: establish a physical model of laboratory experiment on proppant transport with a large flat-panel device; establish a drag coefficient model considering wall-retardation effect according to the numerical simulation experiment; establish a computational geometric model; set boundary conditions and physical parameters of the geometric model according to the two-fluid simulation method for solid proppant quasi-fluidization; verify the grid independence of the computational geometric model to obtain the transport characteristics and placement pattern of the proppant in fractures. The present invention employs a numerical simulation method to study the migration and distribution patterns of proppant under the retardation effect of narrow walls during the hydraulic fracturing.

Abstract: The present invention discloses a numerical simulation method for proppant transport considering wall-retardation effect, comprising the followings: establish a physical model of laboratory experiment on proppant transport with a large flat-panel device; establish a drag coefficient model considering wall-retardation effect according to the numerical simulation experiment; establish a computational geometric model; set boundary conditions and physical parameters of the geometric model according to the two-fluid simulation method for solid proppant quasi-fluidization; verify the grid independence of the computational geometric model to obtain the transport characteristics and placement pattern of the proppant in fractures. The present invention employs a numerical simulation method to study the migration and distribution patterns of proppant under the retardation effect of narrow walls during the hydraulic fracturing.

Abstract: A method for determining sand pumping parameters based on width distribution of fracture, including: acquire basic parameters of a target reservoir, simulate a propagation of the fracture, and obtain a propagation pattern and width distribution of the fracture; determine a maximum proppant particle size for entering the fracture at all width levels according to statistical results of the width distribution of the fracture; determine a multi-size combination of proppants according to a mapping table for particle size vs mesh of proppants, and determine an initial ratio of the proppant with each particle size; conduct a numerical simulation of proppant transportation in the fracture to determine a retention ratio of the proppants with each particle size; correct the initial ratio of the proppants with each particle size; calculate an amount of the proppants with each particle size according to the final ratio and the sand pumping intensity and fracturing interval length.

Abstract: A method for determining sand pumping parameters based on width distribution of fracture, including: acquire basic parameters of a target reservoir, simulate a propagation of the fracture, and obtain a propagation pattern and width distribution of the fracture; determine a maximum proppant particle size for entering the fracture at all width levels according to statistical results of the width distribution of the fracture; determine a multi-size combination of proppants according to a mapping table for particle size vs mesh of proppants, and determine an initial ratio of the proppant with each particle size; conduct a numerical simulation of proppant transportation in the fracture to determine a retention ratio of the proppants with each particle size; correct the initial ratio of the proppants with each particle size; calculate an amount of the proppants with each particle size according to the final ratio and the sand pumping intensity and fracturing interval length.

Abstract: An injection method for a solid retarded acid includes mixing a solid acidic substance with a natural polymer, extruding through an extruder to produce particles; putting the produced particles in a coating pan, and sprinkling zinc acetate powder; turning on the coating pan to rotate while irradiating with an infrared lamp; spraying a glycolic acid aqueous solution with a spray gun, and continuing to rotate to obtain the solid retarded acid; injecting non-reactive liquid and the solid retarded acid into the a sand mixing truck; after the mixture is uniformly mixed in the sand mixing truck, injecting the mixture into a formation by a fracturing truck; conveying the solid retarded acid to a designated location, then stopping a pump, removing pipelines, and opening the well for gushing. The method is good in drag reduction, easy for flowback, thereby reducing the construction cost and facilitating environmental protection, and has broad application.

Abstract: The present invention discloses a method for experimentally determining the influence of acid liquor on the Young modulus of compact carbonate rock.

Abstract: The invention discloses a testing device and method for evaluating effects of CO2 reaction rate of acid rock plate. The testing device includes an acid fluid conveying unit, a CO2 conveying unit, a mixing tank, a plate holder, a recycling fluid tank, and a vacuum pump. The mixing tank includes an acid fluid inlet, a CO2 inlet, and a miscible fluid outlet. The acid fluid inlet is connected with the acid fluid conveying unit, the CO2 inlet is connected with the CO2 conveying unit, the miscible fluid outlet is connected with the plate holder, the plate holder is connected with the recycling fluid tank, and the recycling fluid tank is connected to the vacuum pump. The CO2 conveying unit includes a CO2 cylinder and a gas booster pump which is connected to the cylinder. The outlet of the pump is connected to the gas inlet of the mixing tank.

Abstract: The present invention relates to an injection method for a solid retarded acid. The injection method comprises the following steps: (1) uniformly mixing a solid acidic substance with a natural polymer according to a mass ratio of (0.2 to 1.

Abstract: The invention introduces a method of calculating etching profile of acid-etched fracture system considering complex filtration media, which mainly considers dynamic filtration caused by natural fractures and acid-etched wormholes in acid fracturing, calculates the above filtration process by a numerical method, and finally calculates acid etching profile of acid-etched fracture system based on acid concentration profile. Calculation equations include fluid pressure in natural fractures, filtration velocity in natural fractures, fracture geometry of hydraulic fractures, fluid pressure in matrix rock, acid concentration profile in natural fractures and hydraulic fractures, acid etching width in hydraulic fractures and natural fractures, and length of acid-etched wormhole, etc.

Abstract: The invention discloses a plate holder for simulating flowing of multiphase fluids in fractures, comprising a rectangular box, provided with a fluid inlet and a fluid outlet at the left and right sides respectively, the fluid inlet is connected to a piston at the fluid inlet, the fluid outlet is connected to a piston at the fluid outlet, an internal flow channel of the piston is arranged as a flared guide groove, and the cavity between the pistons is a rock plate cavity; a pair of horizontally-overlapped rectangular rock plates are installed in the rock plate cavity, four sides parallel to the length direction of the rock plate are completely attached and covered with rubber, the outer side of the rubber is covered with steel plate, fastening screws are installed vertically on the four sides of the box that are directly opposite to the steel plate.

Abstract: An experimental test method for dynamic imbibition capacity of shale is provided. The method includes the following steps: core preparation; physical parameter test of shale; experimental loading conditions are determined according to formation stress, formation temperature and hydraulic fracturing parameters; and a dynamic imbibition saturation is defined to characterize a dynamic imbibition amount. Various factors, such as fracturing fluid flow, formation confining pressure, formation temperature and fluid pressure, are used to obtain change rules of dynamic imbibition with time under different construction parameters in shale fracturing process.