涪陵页岩气田立体开发加密井定向钻井技术难点与解决方案

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

摘要:

三层立体开发模式下，涪陵页岩气田采收率显著提升，焦石坝区块采收率从12.6%提升至23.3%。但在密集井网条件下，定向钻井存在诸多难题：井口间距小（6~8 m），平台井直井段防碰风险高；大型压裂导致储层应力场动态重构，同时施工需兼顾剩余气甜点识别与压裂干扰控制；三维轨道设计与高密度井网叠加致使水平段300 m间距内轨迹防碰控制难度倍增。本研究提出基于分离系数的常规加密井轨道优化设计方法，并建立压裂干扰区靶点动态调整技术，形成适用于复杂应力场的三维绕障钻井工艺体系。工程实践表明，该技术体系有效解决了密集布井条件下的三维轨迹防碰难题，为页岩气高效开发提供了重要技术支撑。

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.