A New Method for Obtaining Irreductive Water Saturation and Other Parameters

Abstract

The results show that the resistivity and water saturation data from a core obtained by core electrical experiments are power functions, which can reflect the conductivity characteristics of pore water in rock. Further research shows that when the resistivity data of power function shows a gentle change trend, it shows that the change of movable water pores affects the resistivity data, and when the resistivity data shows a drastic change trend, it shows that the irreducible water conductivity plays a leading role. Therefore, parameters such as irreducible water saturation and movable oil saturation can be determined from the morphological changes of the curve, just as the porosity lower limit of rocks can be determined. Compared with the irreducible water saturation data obtained by mercury injection and other data, a new method is proposed to determine the irreducible water saturation of a core by the cutoff value of slope of power function curve, and the movable oil saturation can be determined by the maximum curvature value of power function curve, which can further obtain the residual oil saturation. The preliminary application shows that the absolute error of irreducible water saturation and other parameters is within 5% and can be used in practice.