枣园油田安山岩油藏超低密度水泥浆固井技术

摘要

为解决常规密度水泥浆体系在安山岩油藏固井过程中易漏失和封隔质量差的难题,优选视密度为0.70 g/cm3的空心玻璃微珠作为减轻材料,依据紧密堆积理论,添加微硅和纤维等外加剂,提高水泥石的强度,从而形成了密度为1.20 g/cm3的超低密度水泥浆体系.对其流变性、沉降稳定性、抗压强度、界面胶结强度进行了评价实验,结果表明其综合性能优良.现场实施5井次,固井质量均合格,油井射孔后获得高产.该技术对大港油田特殊岩性、易漏地层的固井具有借鉴和指导意义.%Cement slurry systems with conventional density are susceptible to problems related to lost circulation and poor sealing performances during cementation in andesite reservoirs.Under such circumstances, hollow micro-spheres of glass with apparent density of 0.70 g/cm3 are used as preferred lightening materials.In accordance with the dense packing theory, microsilica, fiber and other additives were used to enhance strength of the cement stone.In this way, ultra-low-density cement slurry system with density of 1.20 g/cm3 can be generated.Tests have been conducted to determine rheological properties, settlement stability, compressive strength and interfacial cementation strength of the system.Test results show the system has outstanding performances.On-site applications have been conducted in 5 wells with all cementation operations properly qualified.In addition, all such oil producers have high productivities after perforation.The newly developed technologies may provide valuable references and guidelines for cementation of formations with specific lithologic features and formations susceptible to lost circulation in the Dagang Oilfield.