摘要
针对顺北多口超深井采用水基钻井液钻遇奥陶系地层时井壁失稳和井漏并存的技术难题,通过井壁失稳机理分析,设计合成了具有三头双尾结构的Gemini型高温乳化稳定剂和支化型流型调节剂,采用微胶囊化处理方法研制了一种可在156℃以上的温度下激发后膨胀5.37倍以上的温度敏感型膨胀性堵漏材料,开发了一种抗高温强封堵低黏高切油基钻井液体系。室内评价结果表明,该体系抗温不小于180℃,所形成的油包水乳化液滴尺寸为1.2~26.9μm,具有较宽的粒径分布,高温高压滤失量为2.4 mL;塑性黏度不大于40 mPa·s,动塑比为0.31~0.40 Pa/mPa·s,与传统油基钻井液相比,塑性黏度降低10%~15%,动切力提高15%~25%,表现出优异的低黏高切特性和微裂缝的匹配性封堵能力。该体系在顺北Y井进行了现场应用,破碎性地层平均井径扩大率仅为7.77%,钻井过程中除出现一次短暂的放空性漏失外,未见其他明显漏失,避免了奥陶系破碎性地层井壁失稳,减少了裂缝性储层段油基钻井液损耗,助力了亚洲陆上最深定向井纪录的创造和顺北油气资源的提速、提效开发。
Several ultra-deep wells were drilled in the Shunbei Block with water base drilling fluids,resulting in borehole wall collapse and mud losses in the Ordovician formation.Based on the analyses of the mechanisms of borehole wall collapse,a Gemini type high temperature emulsion stabilizer and a branched flow pattern additive with three heads and two tails have been developed.Using microencapsulation treatment method,a temperature-sensitive expandable lost circulation material was developed.This lost circulation material,when excited at 156℃,can expand to a volume that is 5.37 times of its original volume.With these additives,a high temperature oil base drilling fluid was formulated.This drilling fluid has low viscosity,high gel strength and strong sealing capacity.Laboratory evaluation results showed that this drilling fluid can be used at 180℃.The sizes of the emulsified droplets are in a range of 1.2-26.9μm.The HTHP filter loss,plastic viscosity and yield point/plastic viscosity ratio of the drilling fluid are 2.4 mL,≤40 mPa.s and 0.31-0.40 Pa/mPa·s,respectively.The plastic viscosity of the new oil base drilling fluid is 10%-15%lower than that of the conventional oil base drilling fluids,while the yield point of the new oil base drilling fluid is 15%-25%higher than that of the conventional oil base drilling fluids,demonstrating an excellent low viscosity high yield point characteristics and capabilities of plugging microfractures by size matching.Application of the new oil base drilling fluid in the well Shunbei-55X showed that the average percent hole enlargement in broken formations was only 7.77%.Apart from a momentary mud loss into a cave during drilling,there was no other obvious mud losses encountered.Use this new oil base drilling fluid,collapse of the Ordovician formation during drilling was avoided,mud losses into the fractured reservoir were reduced.It also helps set a record of the deepest onshore directional well in Asia and develop the oil and gas resources in Shunbei Block with high speed and high efficiency.
作者
吴雄军
林永学
宋碧涛
金军斌
董晓强
WU Xiongjun;LIN Yongxue;SONG Bitao;JIN Junbin;DONG Xiaoqiang(SINOPEC Research Institute of Petroleum Engineering,Beijing 100101;State Key Laboratory of Shale Oil and Gas Enrichment Mechanism and Effective Development,Beijing 100101)
出处
《钻井液与完井液》
CAS
北大核心
2020年第6期701-708,共8页
Drilling Fluid & Completion Fluid
基金
国家重点研发计划课题“井筒稳定性闭环响应机制与智能调控方法”(2019YFA0708303)
中国博士后科学基金项目“顺北油气田窄密度窗口井筒强化技术研究”(2019M660935)
国家自然科学基金项目“高温高压油气安全高效钻完井工程基础理论与方法”(U19B6003-05)。
关键词
破碎地层
油基钻井液
乳化稳定性
封堵性
抑制性
井壁稳定
防漏堵漏
Broken formation
Oil base drilling fluid
Emulsion stability
Sealing capacity
Inhibitive capacity
Borehole wall stabilization
Prevent and control mud loss
