深层碳酸盐岩气藏不同类型储层衰竭开发物理模拟OA

There exists complexities in productivity and its decline laws in the depletion development of deep carbonate gas reservoirs with strong heterogeneity caused by reservoir type differences.Taking the deep carbonate gas reservoirs in the Sichuan Basin as the research subject,physical simulation experiments of depletion development were conducted on cores with different physical property ranges and reservoir types,under the conditions of formation temperature and pressure.The dynamic variations in parameters such as instantaneous gas production rate,pore pressure,and recovery factor were revealed through these experiments.The gas productivity,production cycle,and producing reserves were analyzed for each reservoir type,and the impacts of vugs and fractures on depletion development performance were elucidated.The following results are obtained.(i)Permeability governs the upper limit of productivity in depletion development,while porosity affects the duration of high production.(ii)Reservoirs with high permeability and low porosity can achieve high recovery factor in the short term,whereas low-permeability,high-porosity reservoirs exhibit lower recovery factor and extended production cycles.(iii)The reasonable combination of fractures and vugs is crucial to high and stable production,while vugs primarily enhance the reservoir space with minimal impact on flow capacity.(iv)Fractured-vuggy reservoirs demonstrate high recovery factor and can produce at high rates in a short period.Vuggy reservoirs exhibit slightly higher recovery factor than porous reservoirs and can sustain lower,stable production rates over a long period.In contrast,porous reservoirs yield the lowest recovery factor and struggle to achieve cost-effective production.It is concluded that the depletion development of deep carbonate gas reservoirs is controlled by the pore-fracture-vug combination.Specifically,fractured-vuggy reservoirs demonstrate strong short-term and long-term productivity,staying as the major contributor to profitable development;vuggy reservoirs require acid stimulation to improve the flow capacity,thereby achieving the beneficial production;and porous reservoirs are not promising for reserve producing and can be considered for regional energy replenishment.