直流电场作用下岩心电阻率试验研究

TEST STUDY ON CORE RESISTIVITY IN DIRECT CURRENT ELECTRIC FIELD

张宁生 吴新民 孙虎

Zhang Ningsheng Wu Xinmin .et al

西安石油学院石油工程系, 陕西西安 710065 长庆石油勘探局, 甘肃庆阳 745106

研究了流体矿化度、含油饱和度和围压 3种因素对饱和流体的岩心电阻率的影响规律。试验表明:随着地层水矿化度提高、含油饱和度下降,岩心的电阻率均下降;随着围压的增加,岩心电阻率升高。Archie公式仅能较好地描述地层水矿化度引起的岩心电阻率变化,但无法很好地解释含水饱和度变化以及围压变化引起的电阻率变化。对于同一区块的岩心,当围压在岩心弹性变形范围内,压力与岩心电阻率也成线性关系。

The influencing tendency of salinity, oil saturation and confined pressure on core resistivity of saturated fluid is studied. Test shows that the core resistivity decreases with the increase of formation fluid salinity and the drop of oil saturation, while it increases with the gain of confined pressure. Formula Archie can only be used to describe how the salinity of formation fluid influence core resistivity, while it does little interpretation on the two factors of oil saturation and confined pressure. When the confined pressure is restricted in the core elasticity limitation, the pressure and core resistivity displays a linear relation for the cores from the same block.

10.3969/j.issn.1000-7393.2001.02.003