低渗透气井短期关井计算地层压力

Calculating Formation Pressure of Low Permeability Gas Well in Short Time Shut-in

"压力是气藏开发的灵魂",准确求取单井的目前地层压力对后期如何配产、制定合理的生产制度至关重要。低渗透气藏由于地层压力恢复慢,短时间关井所测得的井底静压与平均地层压力相差较大,为获得较为稳定的静压,需要长时间关井。为了确保生产任务,采用尽可能少的监测工作量,通过渗流力学中地层压力传播原理,结合压力恢复试井资料,给出井底静压修正方法,使在不同关井时间下的静压更接近于目前的平均地层压力,为现场提供了快速准确估算平均压力的方法。同时将该修正法应用于其他求取地层压力的方法中,如井口压力折算法和压降法,从而得到更为准确可靠的单井地层压力。

＂Pressure is the soul of the gas reservoir development. ＂Getting the accurate single well pressure is crucial to well proration and establishing the reasonable production system. For low permeability gas reservoir,the formation pressure recovery is so slow that the downhole static pressure getting from a short time shut-in varies greatly with the real average formation pressure. Thus,long time shut-in is required to obtain stability of the static pressure. In order to ensure the production task and reducing the workload of data monitoring,the article gives a bottom hole pressure correction method based on the principle of formation pressure transmission in seepage flow mechanics and pressure build-up testing data. This method makes the static pressure in different time is close to the current average formation pressure and provides the production site with fast and accurate method to estimate average formation pressure. At the same time,the pressure correction can be used in other method of formation pressure like wellhead pressure conversion method and pressure drop method to get more accurate and reliable single well formation pressure.