辽河油田无固相强抑制水基钻井液技术

Solid-Free and Strongly Inhibitive Water-Based Drilling Fluid in the Liaohe Oilfield

为解决辽河油田低渗透储层保护难度大、钻井故障发生概率高等问题,以卤水为分散相,通过优选核心处理剂,形成了无固相强抑制水基钻井液。室内性能评价表明:该钻井液能抗高温180℃和25%钻屑;抑制性能好,岩屑滚动回收率达98.7%;对储层伤害小,岩心渗透率恢复率大于90%;能封堵0.1~0.3mm裂缝,具有较高的承压能力和抗返排能力。该钻井液在辽河油田在坨62井三开低渗透储层钻进过程中进行了现场试验,该井三开井段井径规则,未发生井下故障;与邻井相比,机械钻速和产油量高,表皮系数低。这表明,无固相强抑制水基钻井液能满足辽河油田低渗透储层安全钻进和储层保护的要求,具有推广应用价值。

Solid-free strongly inhibitive water-based drilling fluid has been developed by optimizing the key processing agents that take in brine in a dispersion phase.This innovative drilling fluid can effectively eliminate problems,and can protect low-permeability reservoirs and reduce the high frequency of drilling troubles in the Liaohe Oilfield.An indoor performance evaluation showed that newly-developed drilling fluid can provide outstanding inhibition performances,with a rolling cutting recovery rate of 98.7%,and which contains drilling cuttings up to 25%and temperature resistant up to 180℃.There are mild damages to the reservoir.The core permeability recovery rates are over 90%,which can effectively plug fractures of0.1 to 0.3 mm,with high pressure bearing capacity and anti-flowback ability.The drilling fluid was used in the third phase drilling in the Well Tuo-62 in the Liaohe Oilfield,and achieved a regular borehole size without any down-hole trouble.Compared with offset wells,the well has high ROP and oil production,and possesses low skin factors.Research results indicated that the solid-free strongly inhibitive water-based drilling fluid can effectively meet the demands of drilling operations for low-permeability formations in the Liaohe Oilfield,which can be popularized and applied widely in the future.