低渗致密砂岩气藏岩石的孔隙结构与物性特征

根据表面与胶体化学原理，分析了低渗致密砂岩气藏的孔隙结构特征、物性特征以及它们之间的关系。孔隙结构特征表现为喉道小，分形维数高，孔喉径比大，弯曲度大且大多呈扁平形状，物性特征表现为渗透率低且对应力敏感，毛管压力高，毛管压力曲线陡峭，临界水饱和度高，气水界面模糊，并在深盆气藏中可能出现气水倒置、反常低的原生水饱和度、滑脱效应及明显的菲达西流动效应，着重用孔隙结构特征来解释它们的物性特征，对前人关于水膜及边界层性质异常等观点提出了质疑。

RESEARCH ON PORE STRUCTURE AND CHARACTER OF TIGHT SAND GAS RESERVOIRS

According to the principle of surface and colloid chemistry, the pore structure and characteristics of tight sand gas reservoir are analyzed. The pores, most of which are flat in shape, are typical narrow void, high fractal dimension and high pore-throat ratio. The character of the reservoir is typical of low permeability, high stress-sensitive, high capillary pressure value, steep capillary pressure curve, high critical water saturation, blur gas-water contact. Most intriguing in the central basin is the inverted gas-water position, abnormal low initial water saturation, slippage effect and evident non-Darcy flow. The pore structure is emphasized to interpret its characteristic and doubt the previous view of abnormal water film and boundary property.