水淹层自然电位实验测量及结果分析

Measuring Spontaneous Potential of Watered-out Zone in Laboratory and Analyzing Its Results

使砂岩模型饱和不同盐水，以模拟水淹层，并测得相应的自然电位曲线。结果表明，水淹层的自然电位测井响应出现了异常。这种异常主要表现在自然电位异常幅度、自然电位曲线的基线偏移方向以及偏移幅度等几个方面，而且由水淹方式、水淹程度、原生地层水的性质、岩性、层厚和井眼流体性质等因素所决定。说明自然电位测井能够用来识别水淹层及水淹方式、评价水淹程度、确定水淹层的混合液矿化度，但一定要考虑原生地层水的性质、岩性、层厚和井眼流体性质等非水淹因素的影响。

An experiment is done involving saturaton of the sandstone models with different saltwater for simulating watered-out zone and measuring spontaneous potential in laboratory.Experimental results indicate that the response of spontaneous potential logs in watered-out zone is different from that in the zone not watered-out. The differences include the abnormal range of spontaneous potential, the shift direction and range for spontaneous potential baseline. They are determined by watered-out mode and severity,behavior of primary water, lithology and thickness of zone, characteristics of fluid in wellbore ,and so on. As a result, the spontaneous potential logs could be used to identify the watered-out zone, and evaluate their salinity in consideration of the influence of factors such as lithology, thickness of formation and characteristics of fluid in wellbore.