焦页197-4HF井油基钻井液技术

Oil-based drilling fluid technology for Well Jiaoye 197-4HF

焦页197-4HF井是涪陵页岩气田平桥南区197平台的一口三开制大位移开发水平井。该井长水平段位于志留系龙马溪组页岩地层,在钻井施工中面临着极大挑战,一是长水平井段易形成岩屑床,扭矩摩阻大;二是页岩易水化膨胀,造成井壁失稳;三是页岩地层微裂隙发育,钻井液滤失量大。为保证钻井施工正常进行,前期通过室内对比实验,优选出了合适油基钻井液配方。现场使用情况表明,优选出的钻井液配方完全满足现场施工要求,安全顺利地完成了三开长水平段作业。

Jiaoye 197-4 HF was a three-section long reach horizontal well drilled from the No.197 platform in the Fuling Pingqiao Shale Gas Field. The long horizontal section of the well was located in the shale member of Longmaxi Formation in Silurian. Great challenges were faced in drilling:(1) It was easy to form cuttings beds over the long horizontal section with high torque friction;(2) The shale was easy to hydrate and expand, resulting in wellbore instability;(3) Micro-fissures were developed in shale formation, leading to large loss of drilling fluids. In order to ensure the normal drilling operation, the appropriate formulation of the oil-based drilling fluid was optimized through indoor comparative experiments in the early stage. Field application showed that the optimized drilling fluid formulation fully met the requirements of the field work, achieving safe and smooth completion of the third-section horizontal drilling.