Theoretical and laboratory investigations on oil displacement from the rock matrix under capillary forces

Authors: K. Liszka, J. Stopa

The paper contains two parts. The theoretical basis for the process of oil displacement through the water from the fractured porous medium, due to capillary forces, has been discussed in the part No. 1.

The functional equation describing the relative water content increase in the fractured rock matrix, surrounded by the water layer, has also been introduced. This may reflect the actual reservoir conditions, if a fractured oil reservoir is flooded with water, at the moment when the rock matrix porous block has already been surrounded by the water forced in as a result if shifting of watering front in the fractures system.

The impact of particular parameters of this process on its performance has also been determined. This equation is non-linear, and may be solved using numerical methods, in general case.

The analytical solution may be arrived at when the constant value of the mass exchange coefficients has been assumed, as well as simple geometry, such as spherical geometry and process symmetry. Having assumed as above, the analytical solution has been arrived at and compared with a numerical solution.

Taking into consideration the assumptions, the error committed has been slight, in order of few percent. The results of the theoretical contemplations have been compared with laboratory experiments' results, in the second part of the paper.

The detailed description of performed research and its methodology have been given. The experiments have confirmed theoretical results.