气侵溢流最大允许关井套压计算方法探讨

Discussion on Calculation Method of Maximum Allowable Annular Surface Pressure of Gas Invasion

最大允许关井套压是油气井溢流后开展安全压井的一个关键参数,钻井过程发生溢流时,如果处置不当使井口套压超过极限值,容易压漏管鞋处薄弱地层,从而发生井漏、井喷以及井喷失控等复杂情况。为确定合理的最大允许关井套压,对几种计算方法及原理进行了研究和探讨。通过实例模拟和分析,认为发生气侵溢流后地漏试验模型求取的最大允许关井套压误差较大,多相流模型由于考虑因素更全面,模拟更符合实际工况,具有较强的借鉴意义。

The maximum allowable annular surface pressure(MAASP)is an important parameter to realize safe well killing when oil and gas wells overflow.Once overflow occurs,if it is not handled properly,the annular surface pressure will exceed the limit value,which is easy to fracture the weak formation at casing shoe,resulting in lost circulation,blowout,uncontrolled blowout and other complex situations.In order to calculate a reasonable MAASP,this paper compares several calculation methods of calculating the MAASP.Through simulation and analysis for actual case,the results show that the result gap of the leak-off test model is large;The results of multi-phase flow model have a strong reference significance because the factors are more comprehensive and the simulation is more in line with the field reality.