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对于页岩气开发方面的研究,人们一直都将注意力放在如何通过压裂形成大规模缝网上,而忽略了对压后返排模式的研究,但是近年发现有些泥页岩在液体浸泡后不仅渗透性不会变差,甚至还有变好趋势,因此压后到底是直接返排还是焖井后返排成为争论焦点。针对这一问题,采用岩心驱替实验分析的方法,研究了降阻水浸泡后对黏土组分和储层物性的影响。准备两块YY1HF井岩心和500m L降阻水,对岩心进行预处理后,开展页岩脉冲覆压物性测试、氮气吸脱附测试和电镜扫描实验。测试结果表明,降阻水浸泡后,岩石样品的孔隙度、渗透率等参数均有所改善,同时岩心的氮气吸附量降低了33%,比表面积降低了40%。适当的焖井不仅改善了岩石物性参数,还改变了天然气渗流通道,使天然气更容易采出,有利于吸附气向游离气转化,提高气井初期产量和极限采收率。
For the research of shale gas development, people have been paying attention to how to form a large-scale seam network by fracturing, while ignoring the research on the mode of backpressure backpressure. However, in recent years, it has been found that some mud shale Not only permeability will not deteriorate, and even better trend, so after the pressure is directly back to the row or braised wells back into the controversial focus. In response to this problem, the core-displacement experimental analysis method was used to study the influence of the water content on the clay composition and reservoir properties after water immersion. Prepare two YY1HF well cores and 500m L drop-blocking water. After pre-treatment of the cores, pulse shaving physical property test, nitrogen adsorption-desorption test and electron microscope scanning experiment were carried out. The test results show that the parameters of porosity and permeability of rock samples are all improved after the water is soaked in water, and the amount of nitrogen adsorbed in the core is reduced by 33% and the specific surface area is reduced by 40%. Appropriate brazing wells not only improve the petrophysical parameters, but also change the natural gas seepage channel, making it easier for natural gas to be produced, which is favorable for the conversion of adsorbed gas to free gas and the initial production and ultimate recovery of gas wells.