雁翎潜山注气重力驱钻完井难点与对策

雁翎潜山雾迷山地层非均质性强,可钻性差,裂缝孔洞发育,承压能力低,并存在次生气顶,钻井过程中易出现井漏、溢流、卡钻等复杂情况,尾管小间隙固井易导致储层污染、水泥浆低返、环空气窜,给钻完井带来一系列技术难题。针对钻完井过程中的技术难点,提出了相应的技术对策:防漏为主、承压堵漏为辅,优选低密度钻井液配合控压钻井工艺,有效保证裂缝性地层安全钻进;优选个性化高效能钻头,提高机械钻速;优化设计井眼轨道,准确控制水平段位置;优选凝胶堵漏技术、低密度防窜漏水泥浆体系,有效克服固井过程中的水泥浆漏失及预防气窜;优选固井射孔及管外封隔器选择性分段完井方式,满足避水避气开采需求。文中提出的一系列技术对策,为雁翎油田注气驱钻完井提供了技术参考。

Drilling and completion difficulties and solutions for gas assistant gravity driven development of Yanling buried-hill

With strong heterogeneity,poor drillability,well developed fracture and cavern,low pressure bearing capacity and manmade gas cap in the Wumishan Formation of Yanling buried-hill,downhole complex conditions such as lost circulation,kick and pipe sticking are easy to happen.Meanwhile,liner cementing with small clearance is easy to result in formation damage,insufficient top of cement and gas channeling,which will lead to a series of technical challenges to drilling and completion operation.Based on the analysis of the technical difficulties during drilling and completion operation,corresponding solutions are proposed:lost circulation prevention with assisted lost circulation control,MPD technology combined with low density drilling fluid are used for safety drilling in naturally fractured formation;high performance fit-for-purpose drill bit is selected to improve the rate of penetration;optimize the design of the wellbore track,accurately control the horizontal segment position;gel type lost circulation material,low density anti-channeling and anti-lost circulation cement slurry are selected to address the gas channeling and lost circulation during cementing operation;cased bole and completion with external casing packer are selected to meet the exploitation requirement to control gas and water cone.The proposed strategies have provided technical references for the drilling and completion of gas assistant gravity driven development of Yanling buried-hill.