钻井堵漏用特种凝胶的适用性

特种凝胶是一种处理钻井恶性漏失的堵漏剂,它必须不与(或难与)地层水混合而被冲稀才能满足解决裂缝性及破碎性地层恶性漏失的要求.为此,对凝胶与常用钻井液体系的配伍性、拓展其应用范围的交联体系、抗二氧化碳和硫化氢气体的腐蚀性能和其与水泥浆的相容性等适用性进行了研究.结果表明,凝胶与聚合物、聚磺及KCl体系等的配伍性良好,具有改善失水造壁性,提高钻井液黏度切力的作用；化学交联的凝胶体系抗温达到150℃；二氧化碳和硫化氢气体对凝胶的影响小,但在高温下,低pH值对凝胶性能影响大,凝胶可以用于处理高含二氧化碳和硫化氢地区的恶性漏失井漏；凝胶与水泥浆接触不会发生结块和沉淀,凝胶与水泥浆相容性良好；凝胶的适用性足以满足解决裂缝性及破碎性地层恶性漏失的要求.

Research on Special Gel Used for Mud Loss Control

Special gel is a sealing agent for treating vicious lost circulation, and it must not be diluted (or hard to be) by formation water to meet the fractured and fragmentation vicious leakage requirements.In this paper, the compatibility between the gel and common used drilling fluid systems, the crosslinking system, the gel properties affected by CO2 and H2S, and the compatibility between the gel and cement slurry are studied.The experimental results show that gel has good compatibility with used drilling fluid systems, like polymer, polysulfonate and KC1, and it can reduce filtration loss, enhance the viscosity and dynamic shear force, make the high temperature resistance up to 150?, and the influence of CO2 and H2S for gel is weak, however, the condition of low pH has big influence for gel in high temperature.Consequently, gel can treat vicious lost circulation well with CO2 and H2S, also can deal with severe mud loss, for it has good compatibility with cement slurry.