Although significant progress has been made in the tight gas exploration and development, there is still a limited understanding of the fluid charging and hydrocarbon accumulation in the sweet spot. In this study, a novel method is proposed to generate the stochastically constructed porous media which represents the transition region between tight surrounding sandstone and sweet spot. Based on the constructed porous media, the fluid charging and hydrocarbon accumulation processes of the tight reservoir are simulated by the lattice Boltzmann method (LBM). The numerical simulation results show that, although a piston-like pattern can be observed in field-scale simulation or laboratory experiments, at the micro-scale, due to the inherent heterogeneity of the porous media, the fluid charging pattern tends to be fingering-like. The existence of the transition region between tight surrounding sandstone and sweet spot becomes a water-bearing gas layer or even gas-bearing water layer at the top/bottom of the gas layers (sweet spot). The existence of fractures is favorable for hydrocarbon charging into the reservoir rocks, but not for the hydrocarbon accumulation due to the gas escaping through the fractures. Combined with well logging interpretation results, three typical water bodies (isolated water body, water body at the top, or bottom of the gas layer) are identified from the view of fluid charging and hydrocarbon accumulation.

尽管在致密气勘探开发方面已取得重大进展，但对最佳位置的流体充注和碳氢化合物聚集仍知之甚少。在这项研究中，提出了一种新的方法来生成随机构造的多孔介质，该介质代表了紧密的周围砂岩和甜点之间的过渡区域。在构造的多孔介质的基础上，利用格子Boltzmann方法（LBM）模拟了致密油藏的流体充注和油气成藏过程。数值模拟结果表明，尽管在现场规模的模拟或实验室实验中可以观察到活塞状的模式，但在微观尺度上，由于多孔介质固有的异质性，流体的充注模式倾向于指状-喜欢。在致密的周围砂岩和甜点之间的过渡区域的存在成为在气层的顶部/底部的含水的气层，甚至是含气的水层（最佳点）。裂缝的存在有利于碳氢化合物充注到储层岩石中，但由于气体从裂缝中逸出，不利于碳氢化合物的聚集。结合测井解释结果，从流体充注和油气成藏的角度确定了三种典型的水体（隔离水体，顶部或底部的水层）。裂缝的存在有利于碳氢化合物充注到储层岩石中，但由于气体从裂缝中逸出，不利于碳氢化合物的聚集。结合测井解释结果，从流体充注和油气成藏的角度确定了三种典型的水体（隔离水体，顶部或底部的水层）。裂缝的存在有利于碳氢化合物充注到储层岩石中，但由于气体从裂缝中逸出，不利于碳氢化合物的聚集。结合测井解释结果，从流体充注和油气成藏的角度确定了三种典型的水体（隔离水体，顶部或底部的水层）。