精细控压钻井系统

Precise Pressure-Controlled Drilling System

控压钻井技术是在欠平衡钻井基础上发展起来的新型钻井方式,近年来已成为国内钻井新技术研发的热点,其主要目的是为解决"卡、塌、漏、喷"等钻井难题提供有效的手段。控压钻井工艺有多种形式,包括井底恒定压力控压钻井、连续循环钻井和双梯度压力钻井。重点论述了由中国石油集团西部钻探工程有限公司钻井工程技术研究院自主研发的基于井底恒压的控压钻井系统,并就利用该系统实现钻进、停泵接单根、控压起下钻、双梯度钻井液帽压力控制及衔接的工艺方法进行了阐述。结合新疆油田白28井,给出了精细控压钻井系统在该井应用压力控制取得的成果,系统压力控制精度为0.35MPa,达到国外同类产品的控制水平。对控压钻井技术的发展提出了加大该技术在漏、喷问题严重的勘探开发区块的推广应用力度的建议。

Pressure-controlled drilling technology,which is a new-type drilling method based on under-balanced drilling,is a focus of new drilling technological development at home in recent years for the purposes to provide an effective way for settlement of drilling bottlenecks,such as 'sticking,collapse,leakage and blowout' There is a variety of pressure-controlled drilling techniques including constant bottom hole pressure drilling,continuous circulation drilling and dual gradient drilling.This paper focuses on pressure-controlled drilling system independently developed by Drilling Engineering Technology Research Institute of CNPC West Drilling Engineering Co.Ltd.on the basis of constant bottom hole pressure drilling.It also elaborates that this system is used for drilling,connection,tripping and dual gradient mud cap pressure control and linkage process.Take Bai-28 Well in Xinjiang Oilfield for an example.This well shows the results achieved by application of the precise pressure-controlled drilling system.The pressure-controlled precision of this system is 0.35MPa,reaching the controlling level of foreign products of the same kind.This paper also puts forward some constructive suggestions on development of pressure-controlled drilling technology,particularly on the technological issues of leakage and blowout.