煤层气羽状水平井井眼轨迹控制技术

Study on well path control technologies for pinnate horizontal CBM wells

为了提高煤层气的钻遇率、减少井下复杂事故,开展煤层气羽状水平井井眼轨迹控制技术研究至关重要。通过分析煤层气产出机理和羽状水平井技术特点,给出了羽状井井眼轨迹控制综合分析流程图及常用的控制方法,详细介绍了随钻电阻率、自然伽马测井等测井响应井眼轨迹综合控制技术及不同地层倾角煤储层井眼轨迹实施跟踪预测控制技术。研究结果表明：准确掌握煤储层物性参数、地层倾角及顶底板岩性等是实现井眼轨迹有效控制的基础和关键,在钻进过程中通过实时跟踪和分析钻井参数,并结合随钻电阻率、自然伽马测井及综合录井信息等对井眼轨迹进行实时监测和调整,可有效控制钻头在目标层中最佳层位延伸钻进,从而可确保煤储层钻遇率及减少井下复杂事故发生。

Pinnate horizontal well technology is one of the main technologies for coal bed methane（CBM） development.It is very important to study on the well path control technology for increasing much more footage in coal seams and decreasing borehole problems.Based on the analysis of CBM generation mechanisms and characteristics of pinnate horizontal well,the flow chart of analysis on well path controlling for pinnate horizontal well and general controlling methods are presented.Besides,some well path control technologies such as log response controlling technology of resistivity-while-drilling and gamma ray logging,etc.,and well path real time tracking and predicting in different dip angles of coal seams are also introduced in details.It comes to conclusions that one of the most important things for controlling well path is to master the accurate parameters for coal seams and strata dips,and to find out the lithologic characters of the adjacent rocks.It could implement the real time controlling and adjusting on the well path with the real time analyses of drilling parameters,resistivity,gamma ray logging,and so on,and it finally could ensure the bit drilling ahead along the optimum position of target zones.