Relationship among porosity, permeability, electrical and elastic properties

Abstract

Electrical resisivity is usually easier to measure in the laboratory and in-situ than permeability. Therefore, a method of combination between permeability and electrical resistivity might be used to define the fluid flow of reservoir rocks from resistivity data. However, estimating permeability from resistivity has been a problem examined by different authors. Furthermore, neither electrical nor elastic data seldom allow us to accurately quantify the hydrocarbon saturation. Hence, a combination of elastic and electrical properties could offer a powerful means of solving the problem of hydrocarbon saturation production. The objective of this study is to experimentally and theoretically revise the relations among the electrical properties, porosity, permeability, and elastic wave velocity. A data set of laboratory measured petrophysical properties, electrical properties and elastic properties of glauconitic greensand from the North Sea Nini Field was used for this study. A linear relationship between laboratory measured electrical properties and permeability could be established if the diagenesis of greensand is know. By combing Archie’s relation and Kozeny’s equation, the greensand diagenesis may be described by the specific surface area of pores. A linear relationship between laboratory measured electrical and elastic properties could be established if the effect of micro structure of greensand is known. Rock physics modeling results show that quartz cementation has a larger effect on elastic properties than electrical properties, while berthierine cementation has a similar effect on elastic and electrical properties. Selfconsistent modeling results show that pore aspect ratios are more sensitive for electrical properties than elastic properties.