基于地质背景约束的低渗透–致密人造岩心制备研究

Low Permeability and Tight Artificial Cores Preparation under Geological Conditions

摘要: 基于地质背景约束的高温高压物理模拟实验，开展低渗透–致密人造岩心制备研究，明确关键温度300℃与关键压力220 MPa，制备的岩心孔隙度小于12%，渗透率小于1.0 mD。利用激光共聚焦显微镜、扫描电镜、微米CT及高压压汞系统分析人造岩心与相同物性真实岩心孔隙结构，结果表明，人造砂岩岩心整体孔隙结构与真实地质样品孔隙结构相似度高，孔隙形态、大小与空间分布与真实地质样品具有可比性，发育石英等自生矿物。该方法立足真实成岩演化过程，在温度和压力控制下正演成岩作用过程，更为真实地还原了地质样品形成过程，制备的人造岩心可替代真实地质样品开展孔隙结构与流动机理模拟等基础研究，为储层有效性评价提供重要参考依据。

Abstract: Based on high temperature (T) and high pressure (P) modeling experiment that is designed under geological conditions, low permeability and tight artificial cores is prepared. The key T is 300 Cen-tigrade and key P is 220 MPa. The porosity and permeability of produced artificial samples are less than 12% and 1.0 mD respectively. A series of analysis including Laser Confocal Microscope (LCM), SEM, Micro-CT and MICP are applied to compare the pore structure of artificial cores and geological cores with the similar physical property. The artificial cores and geological cores are of similar pore structure, and there are very good consistency on pore shape, size and special distribution. Moreover, authigenous mineral, i.e., quartz is observed in artificial cores. The preparation method is based on actual diagenesis process, and forward modeling the whole process under High T and high P, which can reduce the actual formation process of geological samples. The artificial cores can be used in abundant fundamental researches, i.e., pore structure and flowing mechanism etc., providing reference for reservoir effectiveness evaluation.