Dynamic Analysis And Numerical Simulation Of S Gas Storage Reservoir In Songliao Basin

As a peaking facility and strategic reserve for natural gas,underground gas storage is a strategic infrastructure for national energy security.The storage layer is the basic space for the storage and seepage system of underground gas storage,which must be able to hold a certain amount of hydrocarbon gas and effectively seep and transport it.According to the current operational experience of domestic and international gas storage reservoirs,most of them have difficulties in reaching capacity and production,mainly due to the difficulty in realising the injection and extraction and reservoir capacity parameters designed in the initial scheme in the actual dynamic environment of the formation.Based on the construction needs of the S gas storage reservoir in the Songliao Basin,and in order to achieve the capacity and production of the S gas storage reservoir and its safe,efficient and stable operation,this paper takes the S gas storage reservoir in the Songliao Basin as the research object,analyses and investigates the operation status and reservoir characteristics of gas storage reservoirs at home and abroad,and summarises the possible damage to the reservoir of the S gas storage reservoir.A reservoir dynamic analysis method is proposed from four dimensions: pore structure characteristics,reservoir mechanics characteristics,reservoir seepage characteristics and actual operation of the injection and extraction operation system.At the same time,suitable indoor multi-cycle simulation experiments are designed,including multi-cycle stress sensitivity test,reservoir alternating mechanical stability test,multi-cycle gas-water mutual drive and long core injection and extraction simulation test.Based on the indoor experiments,a three-dimensional geological model of the S reservoir was established to simulate the multi-cycle capacity and production characteristics of the reservoir injection,extraction and transportation,providing a reference for reservoir injection and extraction and reservoir capacity parameter optimisation.The present paper reveals the following insights:(1)the rock stress sensitivity of the S reservoir is high,there is a power function relationship between normalised permeability and effective stress,and permeability damage occurs in the early stage of the injection and extraction cycle and is irreversible.At the same time,the sensitivity of different rock samples varies,with high permeability cores being more sensitive than low permeability cores;(2)the results of the alternating mechanical stability test and the comprehensive simulation evaluation of sand emergence indicate that the risk of sand emergence in the reservoir under normal production pressure difference is extremely low and the mechanical stability is good;(3)the gas-water interdrive phase permeability test shows that the relative permeability of the gas phase gradually decreases with the increase in the number of interdrives,the co-permeability interval becomes narrower,and the residual gas saturation The residual gas saturation gradually increases and stabilizes in the range of 10%～15%.(4)Numerical simulation results show that gas well production capacity is generally high during reservoir operation,but there are differences in the injection and recovery capacity of each well;reservoir connectivity is good,pressure distribution is uniform,and no local high-pressure zone is formed;water intrusion is not obvious.The initial gas injection was mainly to replenish the pad gas volume,and the reservoir transitioned from the stable expansion phase to the stagnant expansion phase in the later stages.The reservoir capacity has basically reached capacity in the fourth cycle,and the reservoir is generally capable of reaching capacity and production.