裂缝性地层承压防漏堵漏钻井液技术室内研究

Lab study on pressure-bearing antileakage and plugging drilling fluid technology in fractured formations

裂缝性漏失是钻井施工中比较常见且危害较大的一种漏失类型。针对此技术难题,从分析裂缝性地层的漏失机理入手,提出了承压防漏堵漏技术对策。结合LX区块裂缝性地层的漏失特点,按照多元协同原则,基于平行缝和梯形缝漏失物理模型,分别利用传统的堵漏仪和新型实验装置进行了堵漏材料优选、承压浆悬浮稳定性和承压堵漏性能实验,形成了一套适合于常规地层和储层的可酸溶解堵的承压堵漏剂配方。室内评价结果表明,研发的承压堵漏剂具有较强的悬浮稳定性和封堵承压性能,有效承压值高达28.0 MPa,能够有效封堵井下水力学宽度不超过2.0 mm的裂缝,可满足井下完井承压堵漏技术要求,有望解决常规裂缝漏失技术难题。

Fractured leakage is a common and harmful type of leakage in drilling operations.In response to this technical problem,starting from the analysis of the leakage mechanism of fractured formations,the technical measures for pressure-bearing leakage prevention and plugging are proposed.Combining the leakage characteristics of fractured formations in the LX Block,and by the principle of multiple synergies,based on the physical models of parallel fractures and trapezoidal fractures,the traditional plugging evaluating instrument and the new experimental device were used to carry out the experiments of the plugging material optimization,the pressure slurry suspension stability,and the pressure-bearing plugging performance.And then it was formed a set of acid-soluble pressure-bearing plugging agent formulas suitable for conventional formations and reservoirs.The lab evaluation results show that the developed pressure bearing sealing agents had strong suspension stability and sealing pressure-bearing capability,with an effective pressure-bearing value of up to 28.0 MPa,which could effectively seal fractures with a hydraulic width of less than 2.0 mm.It may meet the technical requirements of pressure bearing sealing of downhole completions,which is expected to solve the technical problem of general fractured leakage.