A Study on Productivity of Ultra-Deep Carbonate Reservoir Oil Well Considering Creep and Stress Sensitivity Effect

For the long-term conductivity degradation of acid-etched fractures in ultra-deep carbonate reservoirs,a fracture permeability evolution model incorporating creep and stress sensitivity effects was established.Building upon this,a numerical simulation model for ultra-deep carbonate reservoirs was developed to quantitatively analyze the impacts of creep,stress sensitivity,and production strategies on well productivity.The research revealed that the creep and stress sensitivity characteristics of acid-etched fracture had a significant impact on the well productivity for ultra-deep carbonate oil reservoir.The larger the creep coefficient and stress sensitivity coefficient,the lower the oil well productivity;the larger the initial reservoir pressure and drawdown pressure,the higher the daily production and cumulative production of the oil well,but the cumulative production growth rate decreased;the cumulative production in the early stage of the release pressure production was significantly higher than that of the pressure controlled production,but with the increase of the pressure controlled time,the cumulative production reversed.When the pressure controlled for three years,the cumulative production increased by 5952 m3(38.8%);as the creep coefficient increased,the cumulative production increased by greater than the pressure released production.It shows that the larger the creep coefficient,the better the effect of controlling pressure production.The research results can provide theoretical basis and technical support for the efficient development of ultra-deep carbonate reservoirs.