As the depth of the well increasing in our oil and gas field development, the well control is more and more important. Conventional well killing methods, such as driller' s method and engineer' s method, are usually applied in dealing with overflow, but these methods may cause a high surface casing pressure, which may exceed the safe range of equipments and lead to an accident. Reverse circulation well killing method is an unconventional well control method that pumps killing fluids through the annulus and excludes the overflow from drill string. Based on previous studies the initial killing displacement calculation method is deduced to prevent gas channeling. Considering the great difference between annulus friction and drill string friction, a security added value for circulating pressure in the processing of killing well according is decided to field experience and deduces the mathematical model of the circulation pressure and stand pipe pressure in the processing of reverse circulation well killing based on gas state equation, and analyzed the trend of circulation pressure and annulus pressure in killing well. Finally, a calculation program is complied . According to the result of example, this program is proofed to be correct and can be applied in the calculation of reverse circulation well killing method.%随着我国油气开发过程中钻井深度不断增加,井控问题越来越重要.而目前处理气井溢流常采用常规压井方法,如司钻法和工程师法,这些方法可能会导致井口套压过大,从而超过其安全承受范围造成事故.反循环压井法是一种从环空泵入压井液,从管柱内,排除溢流气体的非常规压井法.本文在前人的基础上根据气体溢流速度,推导出了防止气窜的最初压井排量.由于环空摩阻和管柱内摩阻差别较大,本文根据现场经验,给出了压井过程中循环压力安全附加值,并根据气体状态方程推导出了反循环压井过程中循环压力和立管压力变化的数学模型,同时分析了压井过程中循环压力和套管压力的变化趋势,最后编制了计算程序.实例计算表明,所编制反循环压井法模拟计算程序计算结果正确,可用于反循环压井过程中的模拟计算.
展开▼
