基于机械钻速的地层孔隙压力随钻监测方法  

Monitoring method for formation pore pressure while drilling based on rate of penetration

作　　者：杨前亮 黄洪林 罗鸣 吴艳辉 李文拓 肖平 YANG Qianliang;HUANG Honglin;LUO Ming;WU Yanhui;LI Wentuo;XIAO Ping(CNOOC(China)Co.,Ltd.Hainan Branch,Haikou 510700,Hainan,China;Key Laboratory of Deep-Sea Deep-Formation Energy Engineering of Hainan Province,Haikou 570100,Hainan,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南省海口市570100 [2]海南省深海深层能源工程重点实验室

出　　处：《石油钻采工艺》2023年第5期548-554,共7页Oil Drilling & Production Technology

基　　金：中海石油(中国)有限公司科研项目“南海西部油田上产2000万方钻完井关键技术研究”(编号:CNOOC-KJ135ZDXM38ZJ05ZJ);中海油“十四五”重大科技项目子课题“深水超深水复杂井安全高效钻完井关键技术”(编号:KJGG2022-0201)。

摘　　要：精确监测地层孔隙压力是及时调整钻进参数、确保安全钻进的重要基础,但目前国内地层孔隙压力随钻监测难度大,精度不足。考虑钻进过程中钻井液渗流引起的近井底地层孔隙压力重分布问题,分析井底压差、钻头单齿吃入井底岩石深度和钻头机械钻速三者间对应关系,推导并建立了地层孔隙压力随钻监测模型(机械钻速法),并将机械钻速法的监测结果与d_(c)指数法和岩石强度法的计算结果进行对比分析。研究结果表明,井底压差与钻井液渗透强度和机械钻速呈正相关关系,与钻头单齿吃入井底岩石深度呈负相关关系;机械钻速法的单点监测精度均高于95%,平均误差只有1.63%,适用性更强。研究成果为钻进参数(尤其是窄密度窗口层段)及时调整提供理论支撑,为安全、高效钻井提供保障。Accurate monitoring of formation pore pressure is a crucial foundation to adjust drilling parameters promptly and ensure safe drilling operations.Currently,domestic formation pore pressure monitoring while drilling is difficult and less accurate.In response,the near-wellbore formation pore pressure redistribution caused by drilling fluid flow during the drilling process was taken into consideration.The correlations among bottom-hole pressure difference,depth of drill bit penetration into the bottom rock and penetration rate were analyzed,and a model(penetration rate method)for monitoring formation pore pressure while drilling was derived and established.Finally,the monitoring results from the penetration rate method were analyzed and compared with the computation results obtained using d_(c) index method and rock strength method.The research results show that there exists a positive correlation between bottom-hole pressure difference and drilling fluid permeation intensity as well as penetration rate,while a negative correlation with the penetration depth of single tooth of the drill bit into the bottom rock.The single-point monitoring accuracy of the penetration rate method is consistently above 95%,with an average error as low as 1.63%,demonstrating its greater applicability.The research results can provide a theoretical support for the timely adjustment of drilling parameters,especially in narrow-density window intervals,ensuring the safety and efficiency of drilling operations.

关 键 词：地层孔隙压力 随钻监测 钻井液渗流 机械钻速 牙齿侵入深度 

分 类 号：TE271[石油与天然气工程—油气井工程]