Abstract: A shear testing system and method of thermo-seepage-mechanical field and engineering disturbance coupling under deep and complex condition are provided. The shear testing system can be used in conjunction with an axial pressure application device to simplify the structure, save costs, and facilitate a triaxial confining pressure—temperature—axial pressure—torsional shear coupled test on a rock specimen. The shear testing system can achieve the following three purposes. First, the shear testing system can convert an axial pressure into a torsional shear force through a transmission mechanism of a power conversion assembly. Second, the shear testing system can apply an axial pressure to the rock specimen fixed between two specimen fixing heads, through a pressure shaft of an axial pressure mechanism. Third, the shear testing system can apply a triaxial confining pressure and a temperature field to the rock specimen.

Abstract: A rock direct tensile test platform suitable for all material test machines includes a support frame. A top of the support frame is fixed with a top plate, and a bearing plate is provided above the top plate. The bearing plate is provided with a plurality of vertical force transferring rods. The force transferring rods vertically penetrate through the top plate and have a sliding fit with the top plate. Lower ends of the force transferring rods are provided with a tensile base. A top of the tensile base is provided with a lower clamp holder. A bottom of the top plate is provided with an upper clamp holder, and a clamp center of the upper clamp holder coincides with a clamp center of the lower clamp holder.

Abstract: A direct tensile and acoustic testing machine under rock seepage includes a sample and a support frame. A top of the support frame is fixed with a top plate, a bearing plate is provided above the top plate, the bearing plate is provided with a plurality of vertical force transferring rods, the force transferring rods vertically penetrate through the top plate and sliding fit with the top plate, lower ends of the force transferring rods are provided with a tensile base, a top of the tensile base is provided with a lower clamp holder, a bottom of the top plate is provided with an upper clamp holder, and a clamp center of the upper clamp holder overlaps with a clamp center of the lower clamp holder. An acoustic component and a seepage component are provided in the upper clamp holder and the lower clamp holder.

Abstract: The present disclosure discloses a method for calculating a safe drilling fluid density in a fractured formation, including the following steps: S1, performing image processing to identify a downhole fracture; S2, establishing three-dimensional (3D) geological models based on parameters of the downhole fracture, and establishing a drilling wellbore model based on a size and length of a wellbore; S3, assigning the model with material parameters, boundary conditions, and upper and lower bounds of an initial drilling fluid density, and calculating accuracy; S4, solving the 3D geological models using a 3-dimension distinct element code (3DEC) and determining stability of a well wall; S5, determining upper and lower bounds of a drilling fluid density using dichotomy; S6, repeating steps S4 to S5; and S7, after set accuracy conditions are reached, saving and outputting the safe drilling fluid density.

Abstract: The present disclosure discloses a method for calculating a safe drilling fluid density in a fractured formation, including the following steps: S1, performing image processing to identify a downhole fracture; S2, establishing three-dimensional (3D) geological models based on parameters of the downhole fracture, and establishing a drilling wellbore model based on a size and length of a wellbore; S3, assigning the model with material parameters, boundary conditions, and upper and lower bounds of an initial drilling fluid density, and calculating accuracy; S4, solving the 3D geological models using a 3-dimension distinct element code (3DEC) and determining stability of a well wall; S5, determining upper and lower bounds of a drilling fluid density using dichotomy; S6, repeating steps S4 to S5; and S7, after set accuracy conditions are reached, saving and outputting the safe drilling fluid density.

Abstract: A method for predicting and optimizing an ROP for oil and gas drilling based on Bayesian optimization includes: acquiring raw drilling data according to a preset sampling period, constructing an initial sample data set based on the raw drilling data, constructing an ROP prediction model based on the initial sample data set, and predicting an ROP at a next sample point through a Gaussian process regression based on the ROP prediction model. The present invention realizes rapid analysis of historical drilling data and accurate prediction of an ROP range at a sample point in a feasible domain. The method can obtain an optimized ROP and an optimized engineering parameter through Bayesian optimization, and obtain an engineering parameter corresponding to an optimal ROP. The method has few restrictions on the drilling engineering parameter and the raw formation parameter, improves prediction accuracy, and avoids the problem of blurred parameter value boundaries.

Abstract: A method for predicting and optimizing an ROP for oil and gas drilling based on Bayesian optimization includes: acquiring raw drilling data according to a preset sampling period, constructing an initial sample data set based on the raw drilling data, constructing an ROP prediction model based on the initial sample data set, and predicting an ROP at a next sample point through a Gaussian process regression based on the ROP prediction model. The present invention realizes rapid analysis of historical drilling data and accurate prediction of an ROP range at a sample point in a feasible domain. The method can obtain an optimized ROP and an optimized engineering parameter through Bayesian optimization, and obtain an engineering parameter corresponding to an optimal ROP. The method has few restrictions on the drilling engineering parameter and the raw formation parameter, improves prediction accuracy, and avoids the problem of blurred parameter value boundaries.

Abstract: Disclosed are a rock drilling experimental device and a method for simulating true triaxial conditions of deep well drilling; the device includes an energy supply module, an experimental loading module, a hydraulic supply module, a parameter control module and a data acquisition module. The device provides power through the energy supply module; the experimental loading module applies three directional stresses, a liquid column pressure and a pore pressure to a rock specimen by simulating a formation environment, and simultaneously drills into the rock specimen with a bit; the hydraulic supply module provides a hydraulic pressure to the liquid column pressure, the pore pressure and the three directional stresses in the experimental loading device; and the parameter control module is used to control a displacement module of the experimental loading module to move, and adjust a displacement, the pressure and a temperature to the target values.

Abstract: Disclosed are a rock drilling experimental device and a method for simulating true triaxial conditions of deep well drilling; the device includes an energy supply module, an experimental loading module, a hydraulic supply module, a parameter control module and a data acquisition module. The device provides power through the energy supply module; the experimental loading module applies three directional stresses, a liquid column pressure and a pore pressure to a rock specimen by simulating a formation environment, and simultaneously drills into the rock specimen with a bit; the hydraulic supply module provides a hydraulic pressure to the liquid column pressure, the pore pressure and the three directional stresses in the experimental loading device; and the parameter control module is used to control a displacement module of the experimental loading module to move, and adjust a displacement, the pressure and a temperature to the target values.

Abstract: The present invention relates to a method for predicting and optimizing a penetration rate in oil and gas drilling based on a CART algorithm.