Sengupta, Sujit Kumar, Cities Service Co., Hayatdavoudi, A., University of Southwestern Louisiana, Tiab, J.O., University of Oklahoma, Kalra, Satish Kumar, LeBlanc, James L., and Schluntz, E.K., University of Southwestern Louisiana Members SPE-AIME

Abstract

Recent investigations have established the fact that authigenic clays may be dislodged during the enhanced oil recovery operations. However no mechanical stabilization of these clays along with chemical treatments has been fully used or investigated. The mechanical unstability of the clays is due to stress variation at the pore surfaces of the reservoir rock during the flow of pseudoplastic fluid such as polymer, etc. An pseudoplastic fluid such as polymer, etc. An equation has been derived which shows the relationship between the stress developed and the radial distance from the well bore at constant injection pressure.

The analysis of this equation shows that the stress is maximum near the well bore and decreases rapidly with distance. Graphs have been plotted to show further the effect of flow rate and power law coefficient on the stress.

Introduction

The pseduoplastic fluid flow through porous media has gained considerable importance because of their increasing uses as displacing fluid for improved recovery technique.

The behavior of the movement of these types of fluid is quite different than ordinary fluid (i.e. Neutonian fluid). These fluids in fact adds to the permeability reduction as a result of pore throat blockage near the well bore which plays an important role in success or failure of improve oil recovery project, by injection of pseudoplastic fluids. To consider, the behavior pseudoplastic fluids. To consider, the behavior of the movement of the pseudoplastic fluid, consideration of the stress development at the junction of the rock pore surface and the fluid will lead a better understanding. See Figure (1)

To consider the theory of relation between stress and radial distance, we have to proceed in two steps, first, study the stresses that are developed if the fluid is flowing in an open space without any constriction, second, to study the effect of the development of these stresses in porous media. porous media. The viscosity correlation of the pseudoplastic fluid can be written as

(1)

and for the power law model

(2)

From equation (1) and (2) we have

(3)

The flow of fluid (pseudoplastic fluid) through porous media is given by porous media is given by

(4)

where

at a continuous injection, where the pumping of fluid has already started

(5)

substituting equation (3) and (5) in equation (4) we have

......(6)

p. 245

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