伊朗Hendijan区块钻井难点及应对策略

Drilling difficulties and counterbalance measures for Hendijan oilfield in Iranian Persian Gulf

通过对Hendijan油田地质岩性以及钻井工况分析,其中中上部地层软塑性泥岩发育,存在硬石膏夹层,易塌易卡,钻压变化大,牙轮和PDC钻头均易严重泥包,机械钻速低;中下部地层存在高压盐水层,钻井液密度达到2.21g/cm3,安全密度窗口窄,井控风险高。通过优选出PDC+PDM底部钻具组合、赤铁矿饱和盐水聚合物钻井液体系和高压盐水层安全施工工艺解决机械钻速低、井控风险高等难题。通过该技术工艺的在HD-20井的实施,平均机械钻速由邻井2.1m/h提高到3.65m/h,提速74%,电测和下套管作业顺利。为在该海域安全施工积累了宝贵的经验,为同类型井的钻井施工提供了重要参考和宝贵的经验。

Enormous soft and plastic marl plus clay stone,interbedded anhydrate exist in the upper section of Iranian Hendijan oilfield,which bring drilling difficulties such as hole collapse,pipe stuck,weight on bit bouncing,severely bit balling up and low ROP. Due to high pressure salt zone exists in the lower section,whose pressure gradient equals 2.21,what else,mud weight window is narrow,so the risk of well control is high. For these drilling difficulties,picking up ROP,PDC+PDM bottom hole assembly,saturated salt drilling fluid and safe drilling techniques for high pressure salt zone are developed. The combination of techniques is conducted in well HD-20,which ROP is increased from 2.1 m/h to 3.65 m/h by 74% picked up. Additionally,this well wire logging and running casing operations are smoothly. This well provides an important reference and accumulating operational experiences for this oilfield.