Based on well test interpretation, production performance analysis, overburden permeability and porosity test, gas-water core flooding test and high-pressure mercury injection, a quantitative correlation has been built of in-situ effective permeability with routine permeability and water saturation, and the ranges of Main Flow Channel Index (MFCI) are determined for different permeability levels in porous sand gas reservoirs. A new method to evaluate the in-situ effective permeability of porous sand reservoir and a correlation chart of reserves producing degree and main flow channel index are established. The results reveal that the main flow channel index of porous sand gas reservoirs has close correlation with routine matrix permeability and water saturation. The lower the routine matrix permeability and the higher the water saturation, the lower the MFCI is. If the routine matrix permeability is greater than 5.0×10^–3, the MFCI is generally greater than 0.5. When the routine matrix permeability is from 1.0×10^–3 to 5.0×10^–3, the MFCI is mainly between 0.2 and 0.5. When the routine matrix permeability is less than 1.0×10^–3, the MFCI is less than 0.2. The evaluation method of in-situ effective permeability can be used to evaluate newly discovered or not tested porous sand gas reservoirs quickly and identify whether there is tight sand gas. The correlation chart of reserves producing degree and main flow channel index can provide basis for recoverable reserves evaluation and well infilling, and provide technical support for formulation of reasonable technical policy of gas reservoir.

根据试井解释，生产性能分析，覆盖层渗透率和孔隙率测试，气水岩心驱替测试和高压注汞，建立了现场有效渗透率与常规渗透率和水饱和度的定量关系，并且确定了多孔砂岩气藏中不同渗透率水平的主流通道指数（MFCI）范围。建立了评价多孔砂储层地层有效渗透率的新方法，建立了储量生产程度与主流道指标的相关图。结果表明，多孔砂岩气藏主流通道指数与常规基质渗透率和含水饱和度密切相关。常规基质渗透率越低，水饱和度越高，MFCI越低。如果常规基质渗透率大于5.0×10^–3，MFCI通常大于0.5。当常规基质渗透率从1.0×10 ^-3到5.0×10 ^-3时，MFCI主要在0.2和0.5之间。当常规基质渗透率小于1.0×10 ^-3时，MFCI小于0.2。地层有效渗透率的评价方法可用于快速评价新发现或未测试的多孔砂岩气藏，并确定是否存在致密砂岩气。储量生产程度与主流道指标的关联图可以为可采储量评价和注井提供依据，为制定合理的气藏技术政策提供技术支持。