Prediction of vertical permeability and reservoir anisotropy using coring data

Shedid A Shedid

doi:10.1007/s13202-019-0614-0

Abstract

Most reservoirs have different degrees of permeability anisotropy. Optimization of recovery is crucially dependent on the reservoir quality and anisotropy. The ratio of vertical and horizontal permeability is important when reservoir anisotropy (Kv/Kh) and heterogeneity cannot be neglected. Therefore, an accurate knowledge of vertical and lateral permeability distribution is essential for better reservoir characterization. This work uses routine core data for analysis to develop new correlations and characterization of a sandstone reservoir under development. The two main goals of this study are to use core data to (1) develop correlations capable of predicting vertical permeability from horizontal permeability or mean hydraulic radius and (2) develop another correlation capable of predicting the permeability anisotropy ratio (Kv/Kh) using effective porosity data. To accomplish the objectives of this project, various petrophysical properties were experimentally measured for 112 core samples extracted from an actual sandstone reservoir. The measurements included vertical permeability, horizontal permeability, effective porosity and saturations of oil and water. Applications of the developed results of this study help enhancing the prediction of vertical permeability, improving reservoir characterization and providing better simulation studies.

Highlights

Introduction and literature reviewIn early studies of reservoir engineering, the reservoirs are assumed to be homogeneous, isotropic and uniform
It is important to develop a relationship between microscopic level attributes and microscopic core data based on the concept of hydraulic mean radius
A log–log plot of vertical permeability versus mean hydraulic radius is presented in Fig. 6 with a good correlating coefficient of 0.82

Summary

Introduction and literature review

In early studies of reservoir engineering, the reservoirs are assumed to be homogeneous, isotropic and uniform. Majority of other studies had confirmed a general conclusion that vertical permeability decreases with depth (Clark 1969; Osisanya et al, 1998; Zahaf and Tiab 2002; Iheanacho et al 2012). It is important to develop a relationship between microscopic level attributes and microscopic core data based on the concept of hydraulic mean radius. This is because the hydraulic mean radius considers variations√in permeability and porosity as it is defined to be equal to K∕. Kv and Kh are vertical and horizontal permeability (md), respectively, and φ is the effective porosity (fraction)

For Kv is bigger than Kh

Conclusions