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低渗致密气藏复杂的储层特征和充注机理是导致其气藏压力与含气性与常规砂岩迥异的关键因素.选取苏里格气藏42块岩心,开展气藏充注模拟实验,实验中考虑温度影响,逐级增加充注动力,模拟储层低速缓慢充注过程.系统研究了储层物性、充注动力、充注温度3个关键因素对充注成藏的影响,分析了充注过程中气、水产出机理,提出了含气性与储层物性、充注动力为正相关的对数函数关系.研究结果表明:1)低渗致密储层存在充注门限压力,渗透率0.10mD和0.01mD的储层,充注门限压力达2.0 MPa和10.0 MPa.开始进气后,源储压力存在平衡过程,储层越致密,门限压力越高,平衡过程越慢,最终平衡压力越高.2)门限压力和平衡压力是储层含气性变化的拐点,将充注过程划分为3个不同阶段:临界进气阶段,快速增长阶段和平缓增长阶段.不同阶段含气性上升速度和幅度不同,孔隙出水部位不同.3)相同储层及充注动力时,提高充注温度,含气性可上升5%~10%.
Complicated reservoir characteristics and filling mechanism of low permeability tight gas reservoirs are the key factors leading to different pressure and gas-bearing properties of gas reservoirs compared with conventional sandstones.Selecting 42 cores in the Sulige gas reservoir, the reservoir filling simulation experiments are carried out, In the experiment, considering the effect of temperature, the charging power was increased step by step to simulate the process of low-speed slow filling of reservoirs.The effects of reservoir physical properties, charging power and charging temperature on charge-accumulation were systematically studied and analyzed The relationship between gas-bearing property and reservoir physical property and charging power is positive logarithmically, and the results show that: 1) There exists the threshold pressure of infiltration, the infiltration Rate of 0.10mD and 0.01mD of the reservoir, filling the threshold pressure of 2.0 MPa and 10.0 MPa. After the beginning of intake, the source reservoir pressure balance process, the more dense reservoir, the higher the threshold pressure, the balance process is slower, the final balance The higher the pressure is. (2) The threshold pressure and equilibrium pressure are the inflection points of the change of gas content in the reservoir, and the charging process is divided into three different stages: critical stage, rapid growth stage and gentle growth stage. The rate of rise and amplitude are different from the pore water outlet Different .3) and the reservoir when filling the same power, the temperature increase filling containing gas may be increased by 5% to 10%.