提高志留系龙马溪组螺杆取心收获率技术  

Screw tools to improve the recovery of coring in the Silurian Longmaxi Formation

作　　者：段绪林 熊鸿照 朱绍文 刘书培 卓云 杜世轶 DUAN Xulin;XIONG Hongzhao;ZHU Shaowen;LIU Shupei;ZHUO Yun;DU Shiyi(Chuandong Drilling Company,CNPC Chuanqing Drilling Engineering Company Limited,Chongqing 401120,Chi-na)

机构地区：[1]中国石油集团川庆钻探工程有限公司川东钻探公司,重庆401120

出　　处：《天然气勘探与开发》2024年第3期105-110,共6页Natural Gas Exploration and Development

摘　　要：志留系下统龙马溪组页岩致密,常规取心钻速低,采用新工艺螺杆取心后,取心钻速提高50%以上,但受掉心多发以及单次取心进尺差异大影响,实际操作可行性较低,从而使螺杆配套取心技术难以发展与推广。针对高转速螺杆取心作业难点,深入分析龙马溪组各小层岩石特性和螺杆取心技术特点,开展螺杆选型和取心参数优化研究,形成了龙马溪组螺杆长筒取心工艺技术。研究结果表明:①优选螺杆,并分层段优化取心排量控制方法,控制岩心直径大小,防止割心环节发生岩心抽筒;②采取停泵割心并优化循环排量,防止循环过程中岩心掉井。该技术在Z301、Z221井龙马溪组现场试验,2口井共取心7筒次,取心进尺174.50 m,心长173.73 m,收获率99.56%,岩心收获率显著提升,实现了螺杆取心工艺技术突破。该技术可在页岩、砂岩、石灰岩、铝土质泥岩等可钻性较差地层推广应用,解决取心钻速低的难题。Routine coring in tight shale of the Lower Silurian Longmaxi Formation exhibits low rate of penetration(ROP).While some new coring technologies by screw tools may achieve an improved ROP by more than 50%.However,they features low feasibility due to frequent core fall and big difference in each coring footage,which impedes their promotion.Thus,taken difficulties in high-speed screw coring into account,not only rock properties were analyzed for every member of Longmaxi Formation but technological characteristics were discussed.And both screw selection and coring parameters were optimized.Additionally,one technique of long-barrel screw coring was built.Results show that(i)screw tools are selected properly and a method to govern coring displacement is optimized in individual member to further bring core diameter under control and prevent cores from barrels during core cutting;and(ii)cores are cut with pump off and the circulation displacement is optimized to avoid cores falling.This built technique was applied to the Longmaxi Formation in Z301 and Z221 wells,and totally 7 barrels were achieved with the coring footage of 174.50 m,the length of 173.73 m,and the recovery of 99.76%,respectively.A remarkable increase in this recovery signals breakthrough made in screw innovation.And this technique may solve low coring ROP in shale,sandstone,limestone,aluminaceous mudstone even with poor drillability.

关 键 词：早志留世 螺杆取心 收获率 取心进尺 机械钻速 

分 类 号：TE244[石油与天然气工程—油气井工程]