Regional Productivity Prediction Technology for Abnormal High Temperature and High Pressure Gas Reservoirs in Western South China Sea

A large number of high temperature,high pressure and high carbon dioxide gas reservoirs exist in the western South China Sea. Gas well test cost is high and productivity prediction is difficult in "three high" gas reservoir. Design Variable internal pressure,establishment of irreducible water stress sensitivity test and PVT test of natural gas Containing CO₂ to study the effect of stress sensitivity,CO₂ content and skin factor on productivity of high temperature and high pressure gas wells. Through a large number of experiments,the "two-stage" stress sensitivity variation law of high pressure gas reservoir is clarified,and the comprehensive evaluation coefficient of stress sensitivity in target area is obtained. The influence of CO₂ content on PVT parameters such as Z-factor and viscosity of natural gas is analyzed,the influence of high pressure is greater than that of low pressure. Based on experimental data,a correction model of full range deviation coefficient suitable for high,middle and low carbon dioxide content is established. Finally,a regional productivity prediction chart considering the influence of reservoir stress-sensitivity,carbon dioxide and skin factor is established,improves the accuracy of productivity prediction and reduces the cost of testing,which has a good application effect in high temperature and high pressure gas wells in the western South China Sea.