Abstract Based upon observations made with a two-dimensional porous cell, which allows direct visualization of fluid displacement processes, theoretical formulations were established for explaining oil displacement by water in a fractured porous medium. The theory rests on the idea that fluids are transported essentially through the fractures by a convective process, whereas water inflow to the matrix blocks is carried out by a dispersive process which depends on the difference between fracture and matrix water saturation. With these considerations, a derivation is presented of an expression for water saturation as a function of distance and time. Agreement between theory and experiment is reasonably good.
Introduction Secondary oil recovery by waterflooding in fractured reservoirs is an area open to theoretical and experimental research, due to the many doubts concerning the fundamental mechanisms that control oil displacement by water in fractured porous media. Notwithstanding the fact that many of the most important oil reservoirs in the world are of the fractured type, very few papers deal extensively with this subject. It is true that a variety of simulators are currently used for studying fractured reservoirs behavior; however, it is generally recognized that these simulators require a more solid theoretical/experimental support to improve their predictive ability
In particular, the literature shows that experimental works are notably scarce. This is due to the technical difficulties arising when one attempts to follow in detail fluid motion within natural rocks, for they are opaque to visible light. Although indirect methods have been used to this end, as for example X-rays, gamma rays, and nuclear magnetic resonance, the information obtained by these methods has not the sufficient resolution to be used in basic research.
The purpose of this paper is to study the oil displacement by water from the theoretical/experimental point of view.
P. 343^