RESEARCH AND PRACTICE OF 'ONE OPENING- ONE CLOSING' PRODUCTIVITY TESTING TECHNOLOGY FOR DEEPWATER HIGH PERMEABILITY GAS WELLS IN SOUTH CHINA SEA

摘要

Risks of hydrate formation and sand formation in the test string,as well as the disadvantages of conventional testing process that are longer in cycle time and higher in cost exist at the formation testing process of deep-water high-yield gas wells in the South China Sea.In order to form a simple and efficient productivity testing method and process,the classic productivity binomial equation is analyzed.The seepage equation when the formation flow has entered the quasi-steady state and the calculation equations of the coefficients A and B of the productivity equation are established.Through "one-opening-one-closing",that is,one-time open well monitoring bottom hole flow pressure and one-time closed well pressure recovery test,by using the pressure recovery well test interpretation results,we obtain binomial productivity equation coefficients A,B,and the binomial productivity equation.By using this test procedure in the South China Sea deep water gas well YL8 -3-1 well,we derived that the formation coefficient of the well is 7030mDm,the permeability is 246mD,the unimpeded flow is 4630x104m3/d.The established IPR curve shows that the area has great exploration potential.The entire test process is about 100 hours,which greatly shortens the test cycle and provides favorable support for the deep water gas well formation test process.