Abstract: Disclosed are a CO2 gas-soluble silicon nanofluid and a preparation method therefor. The method includes: taking nano-silica and grafting a silane coupling agent to obtain modified nano-silica; taking methylsiloxane, fluorosilicone, aminosiloxane and an end-capping agent, and performing polymerization under the action of a catalyst to obtain a functionalized network siloxane; and taking the modified nano-silica and the functionalized network siloxane, uniformly mixing, then heating for a Michael addition reaction, and obtaining the gas-soluble silicon nanofluid after the reaction is completed. The gas-soluble silicon nanofluid microscopically forms a network structure with modified nano-silica as a cross-linking point and polysiloxane as a chain; macroscopically, the effect of viscosity increase of the supercritical carbon dioxide is significant, and the dissolving pressure is low. The interfacial tension and the miscibility pressure between the crude oil and CO2 are significantly reduced.

Abstract: The present invention relates to a bionics-based efficiently transported and packed proppant and preparation method thereof, comprising enhanced fracturing fluid and biomimetic dandelion proppant; the mass ratio of the enhanced fracturing fluid and the biomimetic dandelion is: 1-2:100-400; the 100 pbw of enhanced fracturing fluid includes 0.1-1 pbw of drag reducing agent, 0.01-0.1 pbw of cleanup additive, 0.2-0.8 pbw of clay stabilizer, 0.01-0.05 pbw of bactericide, 0.01-0.2 pbw of nanoparticle enhancer, and water; the biomimetic dandelion proppant consists of modified proppant and modified fiber, and the mass ratio between the modified proppant and the modified fiber is 99-99.9:0.1-1.

Abstract: The invention discloses a method for simulating the discontinuity of the hydraulic fracture wall in fractured reservoirs, comprising the following steps: establish a physical model of the natural fracture; establish a hydraulic fracture propagation calculation equation; establish a natural fracture failure model, calculate the natural fracture aperture, and then calculate the natural fracture permeability, and finally convert the natural fracture permeability into the permeability of the porous medium; couple the hydraulic fracture propagation calculation equation with the permeability of the porous medium through the fracture propagation criterion and the fluid loss to obtain a pore elastic model of the coupled natural fracture considering the influence of the natural fracture; work out the stress and displacement distribution of the hydraulic fracture wall with the pore elastic model of the coupled natural fracture, and analyze the offset and discontinuity of the hydraulic fracture wall according to the dis

Abstract: The invention discloses a method for predicting the optimal shut-in duration by coupling fluid flow and geological stress, comprising the following steps: determine basic parameters; obtain the fracture length, fracture width and reservoir stress distribution based on the basic parameters; calculate the oil saturation, pore pressure, and permeability and porosity after coupling change in different shut-in durations on the basis of the principle of fluid-solid coupling; take the oil saturation, pore pressure, and permeability and porosity obtained in Step 3 as initial parameters and calculate the production corresponding to different shut-in time on the basis of the productivity model; finally select the optimal shut-in time based on the principle of fastest cost recovery. The present invention can accurately predict the optimal shut-in duration after fracturing to improve the oil and gas recovery ratio in tight oil and gas reservoirs with difficulty in development and low recovery.

Abstract: The invention discloses a method for simulating the discontinuity of the hydraulic fracture wall in fractured reservoirs, comprising the following steps: establish a physical model of the natural fracture; establish a hydraulic fracture propagation calculation equation; establish a natural fracture failure model, calculate the natural fracture aperture, and then calculate the natural fracture permeability, and finally convert the natural fracture permeability into the permeability of the porous medium; couple the hydraulic fracture propagation calculation equation with the permeability of the porous medium through the fracture propagation criterion and the fluid loss to obtain a pore elastic model of the coupled natural fracture considering the influence of the natural fracture; work out the stress and displacement distribution of the hydraulic fracture wall with the pore elastic model of the coupled natural fracture, and analyze the offset and discontinuity of the hydraulic fracture wall according to the dis

Abstract: The invention discloses a method for predicting the optimal shut-in duration by coupling fluid flow and geological stress, comprising the following steps: determine basic parameters; obtain the fracture length, fracture width and reservoir stress distribution based on the basic parameters; calculate the oil saturation, pore pressure, and permeability and porosity after coupling change in different shut-in durations on the basis of the principle of fluid-solid coupling; take the oil saturation, pore pressure, and permeability and porosity obtained in Step 3 as initial parameters and calculate the production corresponding to different shut-in time on the basis of the productivity model; finally select the optimal shut-in time based on the principle of fastest cost recovery. The present invention can accurately predict the optimal shut-in duration after fracturing to improve the oil and gas recovery ratio in tight oil and gas reservoirs with difficulty in development and low recovery.

Abstract: Dynamic segmentation model to divide bottom hole net pressure curve into different stages based on slope of curve includes: step S1, establish calculation model of bottom hole net pressure: according to wellhead pressure during hydraulic fracturing in shale gas reservoir, calculate bottom hole net pressure based on fluid dynamics theory; step S2, establishing dynamic segmentation model to divide bottom hole net pressure curve into different stages based on slope of curve by numerical analysis theory; step S3, establish recognition model to recognize extension behavior of underground fracture network based on rock mechanics and fracture mechanics; and step S4, combine step S1, S2, and S3 to realize automatic diagnosis for wellhead pressure curve of hydraulic fracturing in shale gas horizontal well. A diagnosis and analysis method of the wellhead pressure curve of hydraulic fracturing in shale gas horizontal well is described.