Variation Characteristics of In-Situ Stress and Its Influence on Casing Deformation Under Different Fracturing Technology

In recent years, the shale oil development in the Fengnan 4 well area of Xinjiang oilfield is mainly horizontal well development, and different from conventional fracturing development, this block mostly adopts zipper fracturing. In this paper, based on the actual field fracturing and considering the condition of multi-well and multi-fracture, the finite element model of platform well fracturing is established, and the sequential fracturing of platform well and the zipline fracturing are simulated respectively. The variation difference of borehole stress under different fracturing methods is compared and analyzed, and the change law of casing stress and displacement under the condition of ground stress variation is further analyzed. The results show that: 1) In the fracturing process of the platform well, due to the mutual interference of adjacent well fracturing, the non-uniformity of fracture propagation is high, which leads to the non-uniform change of in-suit stress. 2) Under different fracturing technology conditions, the in-suit stress increases to a certain extent, and the minimum principal stress increases more than the maximum horizontal principal stress. 3) The influence of zipper fracturing on the stress value and non-uniformity of the intermediate well is greater than that of sequential fracturing. 4) The zipper fracturing causes uneven casing stress, and the displacement changes of the casing in the direction of the maximum horizontal principal stress occur in different degrees, which accords with the characteristics of extrusion deformation. The research results can provide help for shale gas platform well fracturing mode optimization.