Abstract: Based on the basic principle of SP log and the properties of flooding bed, from the viewpoint of electric circuit, the concept of current increasing factor and the basic principle of SC (spontaneous current) lag are presented. There are two types of flooding models, i. e., partial flooding and multist-age flooding models. The vertical variation of diffuse membrane potential of the flooding bed is given. Using formation superposition method, the theoretical formula of annular spontaneous potential and current of the flooding reservoir is derived. The theoretical curves for different flooding conditionts are plated with computer.

摘要： 本文根据自然电位侧并的基本原理,从水淹层特点出发,用电路的观点,提出水淹层电流增大系数的概念,阐明自然电流测井的基本原理. 文中提出部分水淹和多级水淹两种水淹模式,导出水淹层的扩散吸附电动势的纵向变化规律,利用分层迭加的办法,得出了油层水淹后环自然电位和自然电流的理论公式,并在计算机上绘制出不同水淹状况和水掩程度下的理论曲线.计算结果表明,环自然电位和自然电流理论曲线极值点的偏移程度,与地层水淹状况、水淹程度和厚度有密切关系,为利用环自然电位和自然电流测井曲线判别油层、水淹层提供了理论依据.