普光主体南部区块海相地层安全优快钻井技术实践

Practice of safe optimized fast drilling technology in the marine stratum of southern block of Puguang

针对普光主体南部区块海相地层裂缝发育、存在大段盐膏层、储层井漏风险高、钻井时效低等问题,文中通过引入科学优化钻井系统,建立区域地质模型和岩石可钻性剖面,研选高效钻头和提速工具,实时优化钻井参数;构建强封堵复合盐钻井液体系,动态精准计算钻井液井下循环当量密度,优化钻井液防漏堵漏措施;采用封隔式分级注水泥新型固井工具,形成一整套安全优快钻井技术。该技术在P3021-5井现场应用中取得了良好效果:飞仙关组单趟钻机械钻速达15.22 m/h,创工区最高纪录;盐膏层全程保持稳定,并有效预防了低压储层井漏和卡钻风险;缩短完井周期5 d。

To address the problems of fracture development,large salt-gypsum layer existence,high risk of reservoir fluid loss,and low drilling efficiency in the marine strata of southern block of Puguang,an intelligent drilling optimization system was introduced in this paper to establish regional geological model and drillability profile of rocks,select efficient bits and acceleration tools,and optimize real-time drilling parameters.Strong plugging composite salt drilling fluid system was constructed and lost circulation prevention and plugging measures were optimized by dynamically and accurately calculating down-hole equivalent circulating density of the drilling fluid.The packer-type staged cementing new well cementation tool was used to form a set of safe optimized fast drilling technology.Good results were obtained in the field application of this technology in Well P3021-5.The ROP of Feixianguan Formation for single drilling rig was up to 15.22 m/h,hitting the highest record in the work area.The salt-gypsum layer remained stable throughout the whole process,and risks of lost circulation and sticking were effectively prevented in the low pressure reservoir.Five days were saved during well completion.