威荣深层页岩气田水平段安全提速技术对策

Technical strategy to enhance drilling speed safely of horizontal section for deep shale gas field in Weiyuan-Rongchang Block

兰凯 董成林 李光泉 杜小松

中国石化中原石油工程有限公司西南钻井分公司，四川 成都 610052 中国石化石油工程技术服务有限公司，北京 100029

Southwest Drilling Company, Zhongyuan Petroleum Engineering Co., Ltd., SINOPEC, Chengdu 610052, China Sinopec Oilfield Service Coporation, Beijing 100029, China

以威荣页岩气田为代表的深层海相页岩气产能建设是中国石化“十四五”天然气增储上产的重点区域，但是已完钻井的完钻周期普遍超过设计周期，且卡钻等井下复杂情况频发，无法实现效益开发的目标。针对水平段施工的瓶颈难题，从水平段导向层位选择、钻井参数优化设计和配套工艺措施制定等3个方面开展研究。基于含气性指标和可钻性兼顾的原则，将31￣1小层作为地质导向钻进的目标层；根据钻头二维破岩临界钻压、扭矩的解析公式，建议水平段PDC钻头钻齿后倾角控制在25°以内，钻压在100～150 kN，扭矩限定值在25 kN·m；基于岩屑床冲刷滚动和运移模型，在高转速、大排量随钻清砂工艺基础上，提出用稀浆与稠浆交替举砂来提高复杂井段井筒的清洁效果。现场应用表明，优质储层钻遇率达100 %，机械钻速提高46.51 %，扭矩平稳，对深层页岩气钻井提质提效具有借鉴与指导意义。

The deep marine shale gas field represented by Weiyuan-Rongchang Block is the key area to increase reserves and gas production for SINOPEC in the 14th Five-Year Plan period. However, actual drilling cycle is longer than designed cycle generally, and downhole complex accidents such as sticking take place frequently, which could not realize the target of benefit development. To solve the key construction problems in horizontal drilling section, investigations are implemented on steering layer choice, drilling parameters optimization and supplementary technical measures. Based on gas-bearing index and drillability, layer 31-1 is suggested as the geosteering object. According to analytic formula of 2D rock breaking critical weight on bit(WOB) and torque, it is suggested that the back angle of PDC bit tooth is within 25°, WOB equals to 100￣150 kN and torque limit sets to 25 kN·m in horizontal section. According to rock debris bedding erosion and transport model, alternating cuutings-lifting by thin and thick slurry are recommended to enhance hole cleaning efficiency in complex section on bases of sand cleaning techniques at high rotary speed and large displacement. Field application shows that drilling ratio of high-quality reservoir reaches 100%, drilling speed improves by 46.51%, and torque remains stable. This technology has referential significance for the drilling technology optimization in deep shale gas reservoirs.

10.6056/dkyqt202303019