Research On The Fluid Flow Patterns And Flow Parameters For Liquid Clearing In High Temperature & High Pressure Open Hole Test

With the in-depth exploration and development of high-temperature and high-pressure blocks in the western South China Sea,high-temperature and high-pressure wells are in urgent need of open hole testing,open-hole testing of offshore high-temperature and high-pressure gas wells presents huge risks and challenges.The test fluid has a large specific gravity,and the fluid flow state are complicated;During the flow of the fluid to the ground,the test fluid presents complex phase changes that are difficult to determine;It is difficult to determine the extension length of the test string,resulting in low drainage efficiency and fluid accumulation at the bottom of the well.Therefore,it is necessary to carry out research on the fluid flow pattern and clearing flow parameters of open-hole test at high temperature and high pressure.In this paper,based on the two-phase flow of high-density test fluid and gas-invading gas in the open hole section and test string,the mechanism of flow pattern transition was analyzed using the principle of hydrodynamics,and a method of the test fluid flow pattern discrimination was established;Then,the model of minimum liquid carrying velocity and flow rate under clear spraying condition was established.Numerical simulations of well fluid flow patterns in open-hole tests were performed.The research results show that as the gas production increases,The better the drainage effect.The test fluid cannot be exhausted at low gas production,causing fluid accumulation at the bottom of the well.By reducing the length of the open hole section,reducing the size of the open hole section,and increasing the amount of test string extension,the bottom hole can be prevented from accumulating fluid.The research results in this paper have certain guiding significance for the on-site high temperature and high pressure open hole test.