Study On Rock Mechanics Parameters And In-Situ Stress In Chang 7 Member Of Fan Xue Area In Ordos Basin

The structural position of the study area is located in the east of the sky ring depression in the Ordos Basin.The main target layer is located in the Mesozoic Yanchang formation.It has complex pore structure and strong heterogeneity,which belongs to low porosity and low permeability reservoir.This leads to the lower productivity and the difficulty of exploration and development.So the rock rock force in the study area is carried out.The study of parameters,rock brittleness and ground stress is of great significance for exploration and development in the study area.Through triaxial rock mechanics experiments on the site core,rock mechanics parameters of the rock samples were measured.The stress-strain curve of the rock obtained in the experiment was analyzed and the change characteristics of the rock under triaxial stress change were obtained.There is a positive linear correlation between compressive strength and elastic modulus,and there is a negative linear correlation between elastic modulus and axial strain rate.The logging interpretation method of the shear wave parameters and rock mechanics parameters is studied,and the correlation calculation of the transverse wave parameters and rock mechanics parameters is carried out in the study area with the dynamic logging data.The dynamic and static dynamic and static relations of dynamic and static modulus,Poisson's ratio and compressive strength are established by combining the static mechanical parameters measured by the experiment and the dynamic mechanical parameters of the log calculation.Well logging explains the mechanical parameters of 120 wells in the study area,and draws the plane distribution map of Young's modulus and Poisson's ratio with logging data to get their plane distribution characteristics.A fracture criterion is established to identify the mechanical parameters of the study area,and 120 wells are identified and the fracture development map is drawn.The rock brittleness is very important.In many interpretation models,a suitable calculation model is chosen to calculate the rock brittleness and establish the corresponding brittle log interpretation section.By comparing the brittle interpretation section with the fracture identification section,it is found that brittleness plays an important role in the development of fractures.In the ground stress model,the log data is used to explain the in-situ stress logging,and then the results of the stress calculation are corrected by the experimental data.Finally,the stress logging interpretation section of the 120 wells is established.On this basis,the three stress plane distribution maps are drawn to analyze their plane distribution characteristics.The effect of maximum and minimum stress difference on fracture development is studied.It is found that the greater the stress difference,the easier the cracks are.