基于数字岩心的变质岩裂缝储层微观渗流机理研究——以JZ油田潜山为例

Study on micro-pore structure and seepage mechanism of fractured reservoirs based on digital core:Taking buried hill of JZ oilfield as an example

潜山裂缝性油藏微观基质储集空间类型及渗流特征研究一直缺乏有效方法,导致基质是否出油等关键问题认识不清.引入数字岩心技术,利用CT扫描和立体成像技术,建立不同尺度三维数字岩心模型,提取孔隙、裂隙网络模型,统计分析孔隙结构特征.并通过基于分子动力学的方法进行单相和油水两相渗流模拟,研究微观渗流规律.通过对JZ油田潜山多个岩心样品进行多尺度数字岩心实验,将该区基质储集空间类型分为:溶蚀孔隙型、溶蚀孔洞型、微裂缝型和基岩四类;分别开展两相渗流模拟,得到各类基质的相对渗透率曲线,定量表征了不同储集空间样品微观渗流特征.数字岩心描述的基质孔隙结构、物性参数与区内常规实验结果基本一致.实现了复杂潜山油藏微观基质渗流特征认识的突破,为类似微观储层研究难题提供方法.

There has been a lack of effective research methods on reservoir space types and seepage characteristics of micro matrix in buried hill fractured reservoirs,leading to unclear understanding of the key issues such as whether the matrix can produce oil or not.By introducing the technology of digital core,which use CT scanning and stereo imaging technology,three-dimensional digital core models of different scales are established,pore and fracture network models are extracted,and pore structure characteristics are analyzed.On this basis,molecular-level single-phase and oil-water two-phase flow seepage simulation is carried out by molecular dynamics method,and its micro-seepage law are studied.Through multi-scale digital core experiments on several core in JZ oilfield buried hill,the matrix reservoir space types in this area can be divided into four types:dissolution pore type,dissolution cave type,micro-fracture type and bedrock.Based on the two-phase flow simulation,the relative permeability curves of various matrices are obtained,and the micro-seepage characteristics of various reservoir space samples are quantitatively characterized.The pore structure and physical parameters of matrix described by digital cores are basically consistent with the conventional experimental results in the area.This study has achieved a breakthrough in understanding the permeability of micro-matrix in complex buried hill reservoir development,and provided a method for similar micro-reservoir research puzzles.