顺北油田超深井优快钻井技术

Optimization of Fast Drilling Technology for Ultra-Deep Wells in the Shunbei Oilfield

顺北油田钻井过程中存在大套火成岩易漏易塌、辉绿岩侵入体失稳和古生代地层机械钻速低等问题,导致钻井井下故障较多,钻井周期较长。室内研究认为,二叠系地层微裂缝引起的井漏和火成岩的脆性失稳掉块导致井眼稳定保障难度大是影响优快钻井实施的最大障碍,为此,优化了井身结构和防漏防塌钻井液体系,配套了二叠系火成岩、桑塔木组辉绿岩的安全钻进技术,形成了以井眼稳定保障技术和安全钻井技术为核心的优快钻井技术。该技术在顺北油田5口超深井进行了现场试验,井漏、井壁失稳问题得到有效控制,实现了二叠系火成岩和桑塔木组辉绿岩安全钻进,试验井平均钻井周期为173.42d,与前期已钻井相比钻井周期缩短14.73%。超深井优快钻井技术的实施,为加快顺北油田的勘探开发步伐、建成百万吨产能提供了技术支撑。

Drilling processes of the Shunbei Oilfield are problematized by complicated conditions and prolonged drilling time due to susceptibility of igneous rocks to lost circulation and collapse,instability of ophiolite intrusive masses and low rates of penetration(ROPs)in Paleozoic Formations.Lab research results showed lost circulation induced by micro-fractures in Permian Formations and difficulties in maintaining stability of sidewalls due to chipping of doleritic rocks were key challenges for optimized and fast drilling operations.Under such circumstances,casing programs and drilling fluid systems with desirable lostcirculation and instability resistance properties were developed for the optimized and fast drilling operations.Borehole stability and fast drilling were key attributes.Field tests were implemented for the innovative technologies in 5 existing wells in the Shunbei Oilfield.Test results showed that lost circulation,sidewall instability and other problems were eliminated effectively for safe drilling of Permian igneous rocks and Sangtamu intrusive masses.The average drilling time for these wells was 173.42 d,which was 14.73%shorter than that required prior to application of the optimized fast drilling technologies.Application of the optimized and fast drilling technologies could effectively accelerate exploration and development of the Shunbei Oilfield.In addition,these technologies might provide reliable technical solutions to achieve million-ton oil productivity of the oilfield.