富县区块气层水平井二级井身结构应用可行性分析

Application feasibility of the secondary casing program of the gas reservoirs by horizontal wells in Fuxian block

钻井周期偏长及储层改造规模不足是制约富县区块天然气经济有效开发的主要因素,通过简化水平井井身结构,可大幅缩短钻井周期,实现大规模储层改造。基于实钻地层资料,通过理论分析及数值模拟,明确泥岩易失稳、长裸眼固井难度大、盐水侵及储层保护差等问题,优化设计水平井二级井身结构方案并配套井壁稳定技术,制定井身结构转变预案。应用结果表明,设计方案可保障富县区块水平井二级井身结构顺利实施,缩短钻井周期,为后期改造提供更加安全有效的井眼条件。

The long drilling period and insufficient reservoir reconstruction scale are the main factors restricting the economic and effective development of natural gas in Fuxian block. By simplifying the casing program of horizontal wells, the drilling period can be greatly shortened and the large-scale reservoir reconstruction can be realized. Based on the actual drilling formation data, through theoretical analysis and numerical simulation, it is clear that mudstone is easy to lose stability, there exists difficulty on long open hole cementing, and there is the problem of salt water invasion and poor reservoir protection. It is necessary to optimize the design of secondary casing program scheme of horizontal wells, support the well wall stability technology, and formulate the casing program transformation plan, etc. The application results show that the design scheme can ensure the smooth implementation of the secondary casing program of the horizontal wells in Fuxian block, shorten the drilling cycle, and provide more safe and effective borehole conditions for the later transformation.