New Approach to Determine Saturation in Complicated Geological Conditions

The comparison of two independent methods for determining the coefficient of oil and gas saturation is discussed. The most common method for estimating the coefficient of oil and gas saturation is the use of the Dakhnov -Archi equation, where input parameters are the porosity coefficients, resistance, and empirical coefficients m, n. When constructing a petrophysical model, especially when interpreting the nature of saturation, in horizontal wells it is necessary to take into account the influence of various factors on the logging data. Estimation of the oil and gas saturation coefficient may become more complicated in the case of low contrast of resistance between water-saturated zones and zones with the presence of hydrocarbons. In this paper, an example of successful resolution of a similar problem in a target interval with low resistance values is considered using the advanced set of logging methods in the drilling process. A detailed analysis of the data obtained during the drilling process made it possible to clarify the saturation coefficient in the low-resistance section, and also identify the saturation coefficient in areas with free water below the level of oil-water contact (OWC).