渤海油田火成岩发育区钻井技术研究

Research on drilling technology of igneous rock development area in Bohai Oilfield

为提高渤海火成岩发育区钻井效率,针对前期3口探井钻井过程坍塌掉块、易漏失、机械钻速低等问题,通过实验室研究,对火山喷发相态、火成岩掉块力学性能、水化特性及矿物成分进行分析,并将实验结果指导现场钻井作业,得到以下结论火成岩发育区钻井过程中复杂情况是因火成岩岩性多样,岩石物性差异大造成;一体化复合冲击器配合专用钻头可提高破岩效率,改善机械钻速;PEM钻井液配方基础上以2.0%的RS复配2.0%的TEMP作为降滤失剂,1.0%EPF作为包被剂,更有利于控制火成岩地层坍塌;提高短程起下钻频率,钻具经过火成岩层控制起下钻速度小于0.5 m/s,倒划眼转速小于25 r/min等参数控制可保证井眼规则,减少钻具及电缆阻卡。渤海火成岩发育区钻井技术有效指导了后期3口探井,提高的机械钻速最高达258%,降低钻井周期23%,是火成岩发育区钻井安全的有力保障,对类似海洋油气田开发提供了技术储备。

In order to improve the drilling efficiency in the igneous rock development area of Bohai Oilfield,aiming at the problems of collapse,easy leakage and low penetration rate in the drilling process of three exploration wells in the early stage,through laboratory research,the volcanic eruption phase,mechanical properties,hydration characteristics and mineral composition of igneous rock drop are analyzed,and the experimental results are used to guide the field drilling operation,and the following conclusions are drawn:the complex situation in the drilling process in the igneous rock development area is caused by the diverse lithology of igneous rock and large differences in rock physical properties.Composite impactor with special drill bit can improve rock breaking efficiency and penetration rate.On the basis of PEM drilling fluid formula,2.0%RS is combined with 2.0%TEMP as fluid loss additive and 1.0%EPF as coating agent,which is more conducive to controlling igneous rock formation collapse.Increasing the frequency of short-distance tripping,controlling the tripping speed of drilling tools through igneous rock layer to be less than 0.5 m/s,and controlling the backward reaming speed to be less than 25 r/min can ensure the well rules and reduce the blockage of drilling tools and cables.The drilling technology in the igneous rock development area of Bohai Oilfield effectively guided the later three exploration wells,increased the penetration rate by up to 258%and reduced the drilling cycle by 23%,which was a powerful guarantee for drilling safety in the igneous rock development area and provided technical reserves for the development of similar offshore oil and gas fields.