压裂井水泥浆在海上高压低渗气井的研究与应用

Research and Application of Fracturing Well Cement Slurry in Offshore High Pressure and Low Permeability Gas Well

在海上"低孔低渗"气井的常规固井中,由于其"低孔低渗"特性,固井前气测值低,地层准确压力系数预测困难,固井时处于欠压稳状态,导致气体窜槽,影响固井质量;在压裂作业中,温度和压力变化引起水泥石应力的改变,从而导致水泥石发生破坏、层间封隔失效。为解决上述问题,从增加水泥石韧弹性展开研究,通过优选胶乳、纤维和膨胀剂等材料,研制出适合于海上压裂井固井特点的增韧防气窜水泥浆体系,在现场应用取得良好效果。

Exploitation of gas wells which is low porosity and low permeability for offshore has many technical difficulties. Due to its special characteristics of low porosity and low permeability, low gasometry before cementing, difficult prediction the accurate formation pressure and cementing in under balance, also gas channeling and bad cementing quality is encountered. The article focuses on the research of the anti-gas migration properties. The exploitation of low porosity and permeability wells usually need fracturing operation. As a result, cement stress is change which caused by changes of temperature and pressure, which leads to failure of cement stone and isolation of individual zones. The cement stone which is researched in this article has good flexibility and strain capacity. This cement slurry has been successfully applied to more than ten low permeability gas wells in the China Sea, which has excellent CBL and SBT result which make a significant contribution to exploitation of low porosity and low permeability gas wells.