Evaluation of Lower Limit of Reservoir Physical Properties for Deep Carbonate Gas Reservoir—Taking the Fourth Member of Dengying Formation Gas Reservoir in the Inner Platform of Anyue Gas Field in Sichuan Basin as an Example

Accurate evaluation of the lower limit of reservoir physical properties is the key link of efficient development of deep carbonate gas reservoirs, and there are few systematic studies on their economic benefits and development feasibility, so it is urgent to clarify the lower limit of the physical properties of such gas reservoirs, and find reasonable development methods and favorable areas for efficient development of gas reservoirs, so as to realize the economic and effective development of gas fields and ensure the long-term stable production of gas fields. Therefore, taking the deep carbonate gas reservoir of the fourth member of Dengying Formation in the inner platform of Anyue gas field in Sichuan Basin as the research object, the flow data of cores with different physical properties under different production pressure differences were obtained through the indoor productivity simulation experiment, and the experimental results were extrapolated to the field conditions combined with the yield similarity criterion, and the lower limit evaluation model of gas well benefit production was established. Based on the dynamic coupling analysis, the quantitative correlation chart between reservoir physical parameters (permeability, porosity) and productivity is constructed. The results show that the lower limit of gas well production in the fourth member of taineideng formation is 8 × 104 m3/d. when the effective thickness of the reservoir is 50 m and the production pressure difference is 25 ~ 10 MPa, the lower limit of permeability is 0.21 ~ 0.39 mD, and the corresponding lower limit of porosity is 3.15% ~ 3.49%. This result dynamically couples the lower limit of reservoir physical properties with development benefits, and provides a quantitative evaluation tool for reservoir evaluation, productivity prediction and development scheme optimization of deep carbonate gas reservoirs, which has guiding significance for the economic and efficient development of the same type of gas fields.