为提高四川盆地页岩气产能，以威远页岩气田202和204两个区块为目标区

In order to improve the shale gas productivity in the Sichuan Basin, the two blocks 202 and 204 of the Weiyuan shale gas field are taken as the target blocks, and the geological engineering integrated research idea is adopted. The three-dimensional fine finite element numerical simulation calculation process of the in-situ stress field is proposed and given Numerical calculation results of in-situ stress field. First, use the horizon information provided by seismic waves to establish a geological model and a finite element mesh model. Secondly, combine single-well geomechanics analysis to establish a three-dimensional in-situ stress field of the target block, and then complete the refined finite element mechanical modeling, and finally obtain the block interior Numerical solution of the three-dimensional distribution of stress. Main conclusions: 1) Obtain the numerical solution of the three-dimensional fine geostress field in the Wei 202 block. The maximum horizontal principal stress gradually transitioned from 130° in the northwest/upper left part to nearly 90° in the southeast/lower right part, showing a strike-slip fault stress pattern. 2) Obtain the numerical solution of the three-dimensional fine in-situ stress field in the Wei 204 block. The maximum horizontal principal stress is close to the vertical stress, and the local stress coexists in a normal fault stress mode and a strike-slip fault stress mode. It is found that referring to the microseismic monitoring information to determine the principal stress direction and the numerical solution verification can reduce the numerical solution error. The proposed method effectively compensates for the shortcomings of the analytical method, and the obtained numerical solutions of the three-dimensional fine in-situ stress fields of two shale gas fields during the stable production period can be used for the optimization of horizontal well layout design and the improvement of hydraulic fracturing efficiency.

In order to improve the shale gas production capacity in Sichuan Basin, taking blocks 202 and 204 of Weiyuan shale gas field as the target blocks and adopting the idea of geological engineering integration, the three-dimensional fine finite element numerical simulation calculation process of in-situ stress field is proposed, and the numerical calculation results of in-situ stress field are given. Firstly, the geological model and finite element mesh model are established by using the horizon information provided by seismic waves. Secondly, the three-dimensional in-situ stress field of the target block is established combined with single well geomechanical analysis, and then the refined finite element mechanical modeling is completed, and finally the three-dimensional numerical solution of stress distribution in the block is obtained. Main conclusions: 1) the numerical solution of three-dimensional fine in-situ stress field in Wei 202 block is obtained. The maximum horizontal principal stress gradually transits from 130 ° in the Northwest / upper left part to nearly 90 ° in the Southeast / lower right part, showing a strike slip fault stress mode. 2) The numerical solution of three-dimensional fine in-situ stress field in Wei 204 block is obtained. The maximum horizontal principal stress is close to the vertical stress, and the local stress is positive, and the fault stress mode and strike slip fault stress mode coexist. It is found that referring to microseismic monitoring information to determine the direction of principal stress and check the numerical solution can reduce the error of numerical solution. The proposed method can effectively make up for the disadvantages of the analytical method. The numerical solutions of three-dimensional fine in-situ stress field of shale gas fields in two stable production periods can be used for horizontal well layout design optimization and hydraulic fracturing efficiency improvement.

In order to improve shale gas productivity in Sichuan Basin, taking Block 202 and Block 204 of Weiyuan Shale Gas Field as the target blocks, adopting the idea of integrated geological engineering research, this paper puts forward the three-dimensional fine finite element numerical simulation calculation flow of in-situ stress field and gives the numerical calculation results of in-situ stress field. Firstly, the geological model and finite element mesh model are established by using the horizon information provided by seismic waves; secondly, the three-dimensional in-situ stress field of the target block is established by combining with the single well geomechanical analysis; then the refined finite element mechanical modeling is completed, and finally the three-dimensional numerical solution of the in-situ stress distribution in the block is obtained. Main conclusions: 1) Get the numerical solution of 3D fine geostress field in Wei 202 block. The maximum horizontal principal stress gradually transits from 130 in the northwest/upper left part to nearly 90 in the southeast/lower right part, showing a strike-slip fault stress pattern. 2) Get the numerical solution of 3D fine geostress field in Wei 204 block. The maximum horizontal principal stress is close to the vertical stress, and the local stress shows the coexistence of normal fault stress mode and strike-slip fault stress mode. It is found that referring to microseismic monitoring information to determine the direction of principal stress and checking the numerical solution can reduce the error of numerical solution. The proposed method can effectively make up for the disadvantages of analytical method, and the three-dimensional fine numerical solutions of in-situ stress field in shale gas fields in two stable production periods can be used to optimize horizontal well layout design and improve hydraulic fracturing efficiency.