硬顶法井控技术研究

Research on the Well Control Techniques of Bullheading

对于含硫油气井及钻头不在井底等情况下发生的溢流,不能采用常规压井方法压井,需采用硬顶压井法重新建立井内压力平衡,而建立硬顶法压井参数计算模型及分析硬顶法压井过程中井口套压的变化规律,有助于硬顶法压井成功实施。在分析适用硬顶法压井适应性的基础上,建立了硬顶法压井参数计算模型和井口套压计算方法,分析了井筒内气体体积和压井液排量对井口最大套压的影响。结果表明:储层渗透率大于30mD、裸眼段长度较短和井口承压能力较高的情况适合使用硬顶法;井筒内气体含量越高,硬顶过程中井口套压越高;压井过程中压井液的排量越大,井筒内的摩阻越大,且气液两相进入储层所需要的压力越大。分析计算结果可为现场实施硬顶法压井提供理论支持。

Bullheading can kill well and establish well control for those wells with sulphur gas when conventional well kill method is not suitable. The establishment of bullheading killing model to calculate the parameters and analysis of surface casing pressure in bullheading process can help the successful implementation of bullheading. On the basis of analysis of bullheading killing adaptability, a bullheading killing parameter calculation model and wellhead casing pressure calculation method were built as well as the anal- ysis of effects of gas volume and killing fluid in the wellbore on the maximum casing pressure. The results show that it is suitable to use bullheading when reservoir permeability is over 30 mD, short open-hole and wellhead with high pressure bearing capacity. The larger volume of gas within the wellbore in the process of bullheading,the higher wellhead casing pressure would be. The higher the killing fluid discharge, the greater the friction and the higher the pressure needed for oil and gas to enter into reservoir. The calcula- tion results provide theoretical support for the field application of bullheading.