川东北地区陆相地层井壁稳定性测井分析

Borehole Stability Logging Analysis in Terrestrial Formation in Northeastern Sichuan

川东北地区的工程地质特征复杂,陆相地层井壁失稳现象严重,给钻井工程施工带来了很大困难。结合岩石力学理论,对该区岩心实验数据、测试资料、刻度测井数据进行研究。形成该地区井壁稳定性测井评价方法,建立岩石弹性参数、地层应力、三压力、钻井液密度安全窗计算模型及参数剖面。确定川东北地区影响井壁稳定性的地质因素主要为岩性复杂多变、裂缝发育和纵向多套压力系统等。研究成果在实钻井中获得较好应用效果,为解决该地区陆相地层的钻井井壁稳定性问题提供重要技术支撑。

Because of the complicated geological features, the borehole destabilization seriously influencs the drilling engineering in the terrestrial formation, northeastern Sichuan. The rock mechanics theory is used to study the core experimental data, testing data and calibration log data in this area. Established are the models to calculate and construct the parameters profile including rock elastic parameters, earth stress, three formation pressures and the safety window of drilling mud density. The research also confirmed the main geological factors influencing the borehole de- stabilization in this area are the complicated and variable lithology, developed fractures and multi- suits of vertical pressure system, etc. Moreover, this technology has been used in the drilling wells and obtains a good result, which provides an important technical support for the borehole destabilization evaluation in the terrestrial formation in northeastern Sichuan.