川渝地区窄安全密度窗口天然气深井固井新技术  

New cementing technique for deep gas wells with narrow safe density window in Sichuan and Chongqing

作　　者：陈敏 赵常青 林强 周迎春 廖长平 杨万忠 宾国成 周太彬 Chen Min;Zhao Changqing;Lin Qiang;Zhou Yingchun;Liao Changping;Yang Wanzhong;Bin Guocheng;Zhou Taibin(Engineering Technology Department,CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Si­chuan 610051,China;Downhole Service Company,CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Sichuan 610051,China)

机构地区：[1]中国石油川庆钻探工程有限公司工程技术处 [2]中国石油川庆钻探工程有限公司井下作业公司

出　　处：《天然气勘探与开发》2021年第3期62-67,共6页Natural Gas Exploration and Development

基　　金：国家科技重大专项“大型油气田及煤层气开发”课题“深井超深井井筒安全钻井技术与装备”(编号:2016ZX05020-003)。

摘　　要：川渝地区钻探作业中,长裸眼井段、多压力层系并存、安全密度窗口窄、井漏和溢流共存现象较为普遍,因而固井面临漏失低返、顶替效率低下以及固井后环空带压影响固井质量和井完整性等问题。通过应用精细控压固井新技术,准确掌握地层压力和漏失压力、精确计算固井下套管与泵注期间环空动当量密度,量化作业窗口区间值,使井筒静液柱压力与井口动态控压之和全程处于窄窗口区间内,达到压稳防漏之目的。精细控压固井技术在川渝地区已开展20余井次现场应用,施工过程中均未发生井漏和溢流现象,后期无窜气,固井质量合格率高于80%,较常规方法固井质量的优质率与合格率平均值,提高20%~30%。精细控压固井技术解决了技术难题,为川渝地区窄安全密度窗口天然气深井固井提供了新的技术途径。Drilling operation in Sichuan and Chongqing features long openhole interval,multi-pressure system,narrow safe density window,and coexisting overflow and circulation loss,resulting in low cement top and displacing efficiency,and annular pressure after cementing,which may affect cementing quality and wellbore integrity.For safe well killing and leak protection,a new pressure-controlled cementing technique was adopted,which might make clear the formation pressure and loss pressure,calculate precisely the annular dynamic equivalent density in the process of casing running and pumping,quantify the range of operation window to limit the sum of hydrostatic pressure at wellbore and flowing wellhead pressure within the narrow window at all time.This technique has been applied to more than 20 wells in Sichuan and Chongqing.As a result,there is no circulation loss and overflow in cementing,and no gas breakthrough at the late stage.Furthermore,the qualified rate is above 80%,20-30%higher than the average one obtained from routine cementing techniques.It is a new technical approach to the cementing of deep gas wells with narrow safe density window in Sichuan and Chongqing.

关 键 词：川渝地区 溢漏同存 窄安全密度窗口 深井 固井 新技术 

分 类 号：TE256[石油与天然气工程—油气井工程]