Control of Fines Migration: A Key Problem in Petroleum Production Industry

Abstract

Prevention of formation damage due to release and deposition of fines in reservoirs is important to enhance oil production. It is, therefore, essential to know the critical conditions at which particles release and plug the pore channels. This paper presents a physical model of the process of particle deposition in porous network based on a novel experiment in which suspensions of particles were passed through micro capillaries of different diameters [60 and 100 µm] at different velocities and the rate of particle deposition and consequent pressure build up were monitored. An improved 3D trajectory analysis was developed and it was validated by observing the rate of particle deposition in a micro capillary while injecting bentonite suspensions at different velocities and particle concentrations. A criteria is proposed to predict the critical conditions for particle deposition in a micro capillary. INTRODUCTION Particle's movement and deposition in an oil reservoir mainly depends on the particle's electrophysical properties, the rate of fluid flow and characteristics of the porous media. When immiscible fluids are present in pore spaces, wettability of the particles, relative amount of fluids flowing through the pores and chemical interactions between the particles and the formation fluids also influence the particle movement strongly. Numerous experimental studies have been conducted using sandstone core samples to understand the factors controlling the migration of fine particles in porous network (Muecke, 1979; Gruesbeck and Collins, 1982; Egbogah, 1984; Sarkar and Sharma, 1988; O'Melia and Stum, 1967; Gabriel and Inamdar, 1983). Although a quantitative assessment could not be obtained, the above authors mentioned that the entrainment and deposition of particles at pore restrictions mainly depend on: particle and pore size, concentration of particles, rate of fluid flow, ionic activity of the pore fluids and fluid phases present in pores.