【摘要】 苏里格西区含水气藏高效开发是实现苏里格气田长期稳产的关键，但储层致密、含水饱和度高、产水机理复杂等因素致使气井普遍产水、储量难以高效动用。为探究含水致密砂岩储层微观渗流机理，采用真实砂岩模型开展系列实验，揭示苏里格西区成藏及开发过程中储层孔隙结构内流体赋存.状态和渗流规律，结果表明：（1）研究区储层亲水性特征明显，盒_8上、盒_8下、山₁段束缚水饱和度分别为54.98%、47.37%、61.41%，且储层物性越好、束缚水饱和度越低、气相渗流能力越强、开采效果越好；（2）成藏过程中气驱水存在指状、网状、均匀驱替3种类型，当孔隙类型由较差变为理想时，驱替过程由指状驱替逐渐转变到驱替程度较大的均匀驱替。储层最后留存的水以膜状、绕流、角隅残余水3种状态赋存在孔喉中；（3）不同样品泄压实验显示，气藏开采时气井压力变化规律相似，但储层物性越差、压降速率越慢、泄压时间越长、残余压力越高，对应气井产量越低；（4）建立自由水及可动束缚水相对含量定量化表征公式，其中盒_8上平均自由水饱和度为34.8%，平均毛细管水饱和度为4.6%；盒_8下平均自由水饱和度为10.4%，平均毛细管水饱和度为5.7%；山₁平均自由水饱和度为7.5%，平均毛细管水饱和度为6.0%，为苏里格西区气井降低产水风险、提高采收率提供理论指导。更多还原

【Abstract】 The efficient development of water-bearing gas reservoirs in the western Sulige area is the key to achieving a long-term stable production of 30 billion cubic meters in the Sulige gas field. However, due to the tight nature of the reservoirs, high water saturation, and complex water production mechanisms, gas wells in this area generally produce water, making it difficult to efficiently utilize reserves. To explore the microscopic seepage behavior and water production mechanisms of medium-to-high water-bearing tight sandstone reservoirs, a series of experiments, including gas-water phase permeability, nuclear magnetic resonance, visual fluid.displacement, and pressure relief tests, were conducted using real sandstone models. These experiments were designed to reveal the fluid occurrence states and seepage characteristics within the pore structure of the reservoirs during the formation and development stages in the western Sulige area. The analysis results indicate that:(1)The reservoirs exhibit obvious hydrophilic characteristics, with irreducible water saturations of 54.98%, 47.37%, and 61.41% for the Upper He8, Lower He8, and Shan1 sections, respectively. Reservoirs with better physical properties tend to have lower irreducible water saturation, broader two-phase coexistence regions,stronger gas-phase seepage capacity, and correspondingly better production performance.(2)During gas invasion and displacement processes, there are three gas-water displacement patterns were observed: finger-like displacement, networklike displacement, and uniform displacement. As the pore types improve, the displacement process gradually transitions from finger-like to network-like and finally to uniform displacement with a higher degree of displacement. The water remaining in the reservoir finally exists in the pore throats in the forms of film residual water, bypass residual water, and corner residual water.(3)Pressure relief experiments on different samples show that during the gas reservoir exploitation process, the reservoir pressure decreases rapidly in the early stage and then gradually stabilizes over time. However, Poorer reservoir quality corresponds to a slower pressure decline rate, longer pressure relief duration, and higher residual pressure,which collectively result in lower gas production, longer production cycles, and reduced recovery efficiency.(4)A quantitative representation formula for water production in the reservoirs of the study area is established to calculate the free water saturation for each sublayer of gas wells in the area. The average free water saturation is 34.8% and the average capillary water saturation is 4.6% for the Upper He8; 10.4% and 5.7% for the Lower He8; and 7.5% and 6.0% for Shan1,respectively. This provides theoretical guidance for reducing water production risks and improving recovery efficiency of gas wells in the western Sulige area.更多还原