特低渗透油藏保护油层钻井液研究与应用

以具有典型特低渗透油层特点的西峰油田长6储层为研究对象,分析了储层的物性特征、储层敏感性矿物、地层水性质,进行了室内速敏、水敏、酸敏、碱敏、盐敏等敏感性评价实验,认识了钻井完井液对特低渗透储层的伤害机理和伤害程度,确定了钻井完井液施工参数,并以此为基础研制出一种新型的低固相强抑制低伤害完井液配方。使用低固相强抑制低伤害完井液后用无水煤油驱排,平均静态伤害率为9.6%,均属于轻度伤害。在庄平3井的现场应用表明,该完井液体系适应西峰油田的地质特点,对储层的损害率小于30%。该体系满足了水平井钻井的施工需要,施工作业井下安全,不阻不卡,达到了储层保护要求。

Study and Application of the Completion Fluid in Ultra Low Permeability Reservoirs

Chang 6 reservoir in Xifeng oilfield is characterized by low formation permeability. The physical property, formation sensitivity and formation water were analyzed. Laboratory study was done on flow-sensitivity, water-sensitivity, acid-sensitivity, base-sensitivity and salt-sensitivity, the formation damage mechanism and degree were understood, and the operation parameters of drilling fluid and completion fluid were determined. Based on the study, a new low solids content completion fluid was with strong inhibition and low damage was developed. Static tests done on cores using this fluid showed that the permeability loss by standard saltwater and water-free kerosene was only 11. 78%, while dynamic tests gave a result of 16.99%, meaning that the formation damage wa low. The application of the completion fluid in well Zhuangping-3 showed that the reservoir permeability losses were less than 30%. No drag and torque, and pipe sticking occurred during field operation, and the fluid met the requirement for horizontal well drilling and completion.