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我国多数气藏均具有高含水饱和度特征,储层与水作用机理的认识是指导气藏科学开发的一项重要依据。建立了一套长岩心物理模拟实验方法,分类选择储层基质岩心分别在不同含水条件下,采用湿气开展了气藏衰竭开采物理模拟实验研究,得出了衰竭开采过程中不同渗透率储层实验前后含水饱和度变化特征,发现一项重要的开发机理认识,即不同渗透率砂岩储层与水的相互作用机理差异明显:1水在Ⅰ类、Ⅱ类储层(>0.5×10-3μm2)内具有较好的流动性,在生产过程中岩心含水饱和度会下降,水会随气体一起产出,说明这类储层即使本身含水饱和度较高或者有外来水时,水也不会在储层中过多滞留从而对气相渗流造成致命影响;2水在Ⅲ类、Ⅳ类储层(<0.5×10-3μm2)中渗流能力差,如果气藏没有足够大的能量,这类储层岩心的细微孔喉则会对原始孔隙水产生束缚作用,对外来侵入水产生捕集作用,从而导致储层含水饱和度升高,影响气相渗流能力。这一开发机理认识对于指导高含水致密砂岩气藏制订合理工作制度和开发对策具有一定意义。
Most of our gas reservoirs are characterized by high water saturation. The understanding of the mechanism of reservoir and water is an important basis for the scientific development of gas reservoirs. A set of long core physical simulation experiment method was established. The physical simulation experiments of gas depletion and extraction by moisture were carried out respectively under different water-bearing conditions by selecting the matrix cores of reservoirs. The results show that different permeability reservoirs The variation of water saturation before and after the experiment shows that there is an obvious understanding of the development mechanism that the mechanism of the interaction between sandstone reservoirs and reservoirs of different permeability is obviously different: (1) The water in Class Ⅰ and Ⅱ reservoirs (> 0.5 × 10-3μm2 ) Has good fluidity in the production process of core water saturation will drop, water will be produced with the gas, indicating that even if the reservoir itself has high water saturation or foreign water, the water will not In the reservoirs, too much retention can have a fatal impact on the gas seepage. 2. Water seeps poorly in Class Ⅲ and Ⅳ reservoirs (<0.5 × 10-3μm2). If there is not enough energy in the gas reservoirs, The fine pore throat of layer core will have a binding effect on the original pore water, which will capture the foreign invaded water and lead to the increase of reservoir water saturation and the influence of gas phase seepage. This understanding of development mechanism is of great significance in guiding the formulation of a reasonable working system and developing countermeasures for high-water-tight gas reservoirs.