北部湾盆地开发井表层钻井模式

南海西部海域北部湾盆地地质条件复杂,进行开发井表层钻井时,存在井壁失稳、钻井液性能不易控制、井眼轨迹不易控制等问题,导致表层钻井井眼携岩困难、定向滑动钻进摩阻大效率低,还存在较大的防碰风险。而目前该盆地以低品位油气藏或边际油气田为主,油田开发效益低,因此需要进行有效的钻井成本控制。介绍了北部湾盆地开发井表层钻井的技术难点;通过优化井身结构、选用经济适用型海水膨润土浆钻井液体系、优化设计螺杆钻具组合及改进随钻测量系统,形成了一套提高该盆地开发井表层钻井效率、降低作业风险的方法。现场应用表明,该模式能在保障作业安全与质量的前提下,提高钻井效率,降低钻井成本,该模式也可为现场施工人员提供技术参考。

The pattern of surface drilling in development wells of Beibu Gulf Basin

The geological conditions of Beibu Gulf Basin in the western South China Sea are very complex. When drilling the surface layers of development wells, there existed such problems as wellbore instability, difficulty in controlling drilling fluid properties, difficulty in controlling wellbore trajectory, and so no, which led to difficulty in sand carrying in surface drilling hole, large friction and low efficiency in directional slide drilling, and there also existed great risk of borehole collision. Now this Basin is mainly dominated by low quality oil/gas reservoirs or marginal oil/gasfields and the oilfield has low development benefit, so drilling cost must be controlled effectively. This paper presents the technical difficulties in surface drilling in development wells in Beibu Gulf Basin. A set of method which improves surface drilling efficiency in development wells in this Basin and reduces drilling risks has been developed by optimizing the wellbore configuration, using economic and applicable seawater bentonite drilling fluid system, optimizing the design of positive displacement motor assembly and improving the measurement while drilling system. The field application shows that this pattern can increase drilling efficiency and reduce drilling costs while guaranteeing drilling safety and quality. This pattern can also provide technical references for field workers.