高温高压高产井DST过程中井底流压及井口回压的计算

DST测试期间,为了完成测试任务,通常通过油套环空加压的方式来控制井下不同目的的测试工具。对于高温高压高产井,由于地层压力高,环空使用的液体的密度可能比较高,而测试管柱内,液体组分比较复杂不能简单的使用原油的密度进行计算。为了防止测试管柱的挤毁,文中提出了使用不同油嘴下的井口压力值,测试产量,关井压力恢复过程中的井口压力以及流体性质计算测试期间井底流压,测试管柱内外压,以及防止测试管柱被挤毁而需要施加的最小的井口回压的计算公式。通过使用A油田2口井的DST的测试数据,进行了验证,公式的精度可以满足现场作业的要求。

The Calculation of well bottom flowing pressure and wellhead pressure during DST of high temperature high pressure and high productivity wells

In period of DST testing, in order to complete the task of testing, some tools, which are controlled by annulus pressure and have different purpose, are added into the DST string. For high temperature, high pressure and high productivity wells, the parker fluid also has high weight because of the high formation pressure of formation which is tested, however, the production fluid in the string always has lower weight and the components of the fluid is complex, so the weight of crude oil cannot simply be used as the weight of production fluid. In order to prevent the collapse of the testing string, the calculation method of flowing bottom pressure, internal and external pressure of testing string and the minimum wellhead pressure to avoid the collapse of string, which uses the different wellhead pressures and productivities of different choke, the final wellhead pressure of build-up period and the properties of production fluid, is given in this article. The method is verified by well testing data of two wells in A oilfield, the computation error can meet the requirement of site operation.