下扬子皖南地区皖泾地2井地质特征与优快钻井对策

Geological characteristics of Well Wanjingdi 2 and drilling strategy in Southern Anhui of Lower Yangtze region

皖南地区发育有三叠系殷坑组、二叠系大隆组—龙潭组2套油气成藏系统,但区域上构造复杂,断层发育,地层软硬交错、变换频繁,缩径、井漏、井壁垮塌、卡钻等各种复杂情况时常发生,且局部存在高压气层,钻探施工面临巨大挑战。皖泾地2井通过采用随钻堵漏、复合堵漏、页岩专用取心钻头、混合钻头、强抑制性钻井液等技术对策,实现了该井的优快钻进,将钻井周期缩短了24 d,并采用弹韧性双凝双密度固井技术保证了生产套管的固井质量,为下一步的压裂试气作业提供了技术保障。该套技术体系可为今后该区同类工程的优快钻井施工提供借鉴作用。

There are two sets of hydrocarbon accumulation systems in Southern Anhui namely,Triassic Yinkeng Formation and Permian Dalong Formation-Longtan Formation.However,this region has developed complex structures and faults,and the soft and hard formations were interlaced with frequent changes.Various complex situ-ations such as reduced diameter,lost circulation,wall collapse and stuck drill often occurred,and there is a high-pressure gas layer locally,which has caused huge challenges during drilling construction.By adopting the technical measures of plugging while drilling,composite plugging,special shale-coring bit,hybrid bit and strong inhibitory drilling fluid,the optimal and fast drilling has been realized in Well Wanjingdi 2,so the drilling cycle has been shortened by 24 days.Besides,the elastic and ductile double condensation and double density cementing technology was used to guarantee the cementing quality of production casing,which provides technical guarantee for the next stage of fracturing and gas testing.This technical system can provie some valuable references for similar drilling projects in the future.