Technical challenges and solutions of directional drilling for infill wells in three-dimensional development： A case study from Fuling Shale Gas Field

Abstract:

Under the three-layer three-dimensional development mode， the recovery rate of Fuling Shale Gas Field has significantly increased， and the recovery rate of Jiaoshiba block has increased from 12.6% to 23.3%. However， in the process of three-dimensional development of directional drilling， there are many problems： The wellhead spacing is small （6~8 m）， and the risk of collision prevention in the vertical section of the platform well is high； Large-scale fracturing leads to the dynamic reconstruction of the reservoir stress field， and the construction needs to take into account the identification of residual gas sweet spots and the control of fracturing interference； The three-dimensional track design and the superposition of high-density well pattern make it difficult to control the trajectory collision within the 300 m spacing of the horizontal section. In this study， a conventional infill well track optimization design method based on separation coefficient was proposed， and a dynamic adjustment technology for targets in the fracturing disturbance zone was established to form a three-dimensional obstacle drilling technology system suitable for complex stress fields. The engineering practice shows that the technical system effectively solves the problem of three-dimensional trajectory collision prevention under the condition of dense well placement， and provides important technical support for the efficient development of shale gas.