微裂缝低渗透岩石渗透率随围压变化实验研究

EXPERIMENTAL STUDY ON PERMEABILITY VARIATION WITH CONFINING PRESSURE IN MICRO-FRACTURE AND LOW-PERMEABILITY ROCK

低渗透油藏的开发日益受到重视,然而由于其成岩作用强烈、岩性致密、微裂缝普遍发育等特点,使得渗透率这一关键表征参数具有较强的应力敏感性。针对该问题,从理论研究出发,在一定假设条件下,研究得到了微裂缝低渗透岩石渗透率随围压变化的理论关系式,并在该关系式指导下,选取某油田发育不同程度天然微裂缝的3块低渗透岩心开展室内实验研究。通过对实验数据的分析整理,拟合得出实验关系曲线,从而确定了理论关系式中的待定系数,进而得到了发育微裂缝低渗透岩石渗透率随围压变化定量关系式。

The development of the reservoir with low-permeability is becoming increasingly important. But its strong diagenesis, fine and close lithology and general development of micro-fractures make permeability, the key symptomatical parameter, has strong stress sensitivity. In order to get the quantitative relation between permeability and confined pressure in micro-fracture and low-permeability rocks, a theoretical relation was attained based on theoretical research and some hypothesis. With this guidance, an experimental study was carried out on three low-permeability cores with natural micro-fracture from an oil field. Through analyzing the experimental data and matching work, a relation curve was acquired from the experiment by which we can get the undetermined coefficient of the theoretical relation and finally obtain the quantitative relation between permeability and confined pressure in the micro-fracture and low-permeability rocks.