Numerical Simulation on the Safety and Quality of Cementing by Using Pad Fluid in Horizontal Wells

The failure of wellbore sealing will cause leakage greenhouse gases, such as carbon dioxide and methane, which harm oil gas recovery environmental safety. Cementing is an important part sealing. Only good cementing can keep the seal for a long time improve well life. In this study, we considered construction horizontal shale in eastern China background analysed rheological properties annulus fluid. We developed displacement motion model calculation dynamic equivalent circulation density, numerical simulations were used to study impact dosage injection sequence pad fluid on efficiency density. results show that when composed completely flushing fluid, performance better than spacer. By increasing from 0.3 times annular volume 1.0 times, be increased by 3.3%, retention drilling also reduced 3.6%. However, it lead significant reduction density increase risk leakage. After adding spacer, structure fluid–spacer provides optimal sequence. Considering application status field example well, was shown not only ensure safety operations, but efficiency. have theoretical significance value provide guidance optimisation design engineering scheme.