裂缝性储层应力敏感性研究

因储层流体压力变化,致使储层岩石受到的有效应力发生变化,引起储层渗透率改变,这种现象称为应力敏感性。该敏感性主要与储层岩石的岩性和裂缝特征等因素有关。利用人造裂缝岩样研究了裂缝性储层的应力敏感性损害。结果表明,随着有效应力的增加,裂缝性岩样的渗透率、孔隙度和裂缝宽度下降幅度比较大,但随着有效应力的进一步增加,其下降幅度逐渐减慢,裂缝性储层的渗透率和裂缝宽度与有效应力呈指数关系变化;裂缝性储层存在严重的裂缝滞后效应,即裂缝性储层发生了应力敏感性损害后,即使减小有效应力也不能使裂缝性储层的渗透率恢复到原来的值。

fissured reservoirStudy on the stress sensitivity of fissured reservoir

The effective stress of reservoir rock varies with the reservoir fluid pressure, which accordingly causes reservoir permeability changin-gand this phenomenon is called stress sensitivity. The stress sensitivity is mainly affected by the lithology and fissure characteristics of reservoir rock. The impairment to the fissured reservoir resulted from stress sensitivity has been studied by use of man-made fissured rock sampling. The re-sults show that the permeability, porosity and fissure width of fissured rock samping decrease rapidly as the effective stress increases, but they slow down as the effective stress increases further; the permeability and fissure width of fissured reservoir relate with effective stress in exponent; The impairment to the fissured reservoir caused by stress sensitivity can't be recovered even if the effective stress has been decreased.