东海X区块大位移井提高井壁稳定性技术优化

Optimization of Oil-based Mud in An Extended Reach Well in the East China Sea

东海某区块龙井组底部和花岗组上部杂色泥岩发育,已钻井在龙井组底部和花岗组上部都有不同程度的杂色泥岩垮塌,导致起下钻遇阻频繁,划眼蹩扭、憋泵严重,井下返出大量掉块,导致钻井时效降低,且极易引起复杂情况。为降低钻井作业风险,推进东海气田高效勘探开发,优化本区块大位移井的油基钻井液体系配方,同时制定配套的工程措施,维持井壁稳定性,保障井下安全,提高钻井时效。

The variegated mudstones are developed at the bottom of Longjing Formation and the upper part of granite formation in a block in the East China Sea.There are variegated mudstones collapsed at the bottom of Longjing Formation and the upper part of granite formation,which lead to frequent tripping,poor reaming,serious pump holding,and a large number of blocks returned from the well,leading to reduced drilling eff iciency and extremely easy to cause complex situations.In order to reduce the risk of drilling operation,promote the eff icient exploration and development of Donghai gas field,optimize the formulation of oil-based drilling fluid system for extended reach wells in this block,and develop supporting engineering measures to maintain the stability of wellbore,ensure downhole safety,and improve drilling eff iciency.