Abstract: In response to the problem that the drainage and capacity expansion mechanism of converting gas reservoirs with edge and bottom water into gas storage and its main influencing factors are unclear,taking the Wen 24 Gas Reservoir as an example,an experimental evaluation method for multi-cycle injection-production drainage and capacity expansion in gas reservoirs with edge and bottom water converted into gas storage was constructed.Experiments on the effects of gas injection rate,formation dip angle and reservoir physical properties on multi-cycle injection-production drainage and capacity expansion in gas reservoirs with edge and bottom water were carried out,revealing the mechanism of injection-production drainage and capacity expansion in gas reservoirs with edge and bottom water.The results show that the capacity expansion rate decreases by 2.550 percentage points as the gas injection rate increases from 0.3 mL/min to 0.9 mL/min;when the formation dip angle increases from 0°to 60°,the capacity expansion ability increases by 7.110 percentage points;when the reservoir permeability increases from 25 mD to 107 mD,the capacity expansion rate increases by 7.229 percentage points;in the repeated injection-production stage,the increment in capacity expansion rate in the first two cycles accounts for 85% of the entire stage.Compared with the huff-and-puff method,the injection-production method increases the capacity expansion rate by 2.787-3.978 percentage points.The gas-drive drainage stage has the most significant capacity expansion effect,but as the gas injection rate increases,the capacity expansion efficiency gradually decreases;the injection-production method is more suitable for the conversion of gas reservoirs with edge and bottom water into gas storage.These results have important guiding significance for understanding the capacity expansion mechanism and parameter optimization of converting gas reservoirs with edge and bottom water into gas storage.

Key words: gas reservoir with edge and bottom water, parameter optimization, multi-cycle injection-production, drainage and capacity expansion, gas storage