高压气井修井挤压井井筒流动模型

塔里木油田克深气田超深、高温、高压,部分气井在生产过程中环空异常带压,若长期监控生产,井控风险大,需要进行压井以便开展修井作业。高压气井修井挤压井作业过程井筒流动规律复杂,压井风险高。考虑压井过程井筒-地层复杂耦合流动,建立了高压气井挤压井数学模型,模型预测结果与实测数据吻合较好,能够满足高压气井挤压井施工设计的需要。通过数值计算,分析了高压气井挤压井作业井筒流动规律及影响因素。研究表明,挤压井过程中井底压力和油压对地层渗透率、储层厚度、地层压力、压井液排量等参数较为敏感,储层渗透率和厚度越低,地层压力越高,压井井底压力和油压越高。压井液排量越大,压井持续时间越短,产生的井底压力越高。挤压井作业需根据储层渗透率、厚度及地层压力等参数,确定合理的压力液排量等施工参数,在保证压井成功高效的前提下,避免压漏地层。

Mathematical Model of Wellbore Flow during Squeezed Well Killing for High Pressure Gas Well

There is a number of gas well with sustained casing pressure in Keshen gas reservoir, tarim oilfield characterized by ultra deep, high temperature and high pressure. If these well products under monitoring for long term, the risk of well control is very large, so it is needed to carry out well kill. It is difficult to kill well due to the complexity of wellbore flow during well kill operations in high pressure gas well. In this paper, a mathematical model for predicting the wellbore flow behaviors during well kill with the squeezing method was developed, taking the complex coupling between wellbore and formation during well kill. The predicted results of the model are in good agreement with the measured data, showing that the model has high forecasting precision. The wellbore flow behaviors and main factors influencing the well killing were discussed in this paper. The results show that the bottom hole pressure and tube pressure are sensitive to the thickness and permeability of the reservoir and flow rates of kill fluid. The lower the permeability and thickness of the reservoir, and the higher the formation pressure, the higher the bottom hole pressure and tube pressure. The higher the kill fluid flow rates, the shorter the kill duration, and the higher the bottom hole pressure. It is needed to determine the reasonable kill fluid flow rates and other construction parameters according to the reservoir permeability and thickness and formation pressure. It is important to kill well efficiently and avoid inducing lost circulation.