Extended Contact Stimulation for Carbonate Reservoirs

Abstract

This study investigates the application of the OpenPath Reach (OPR) retarded acid system for the matrix stimulation of the tight dolomitic LD2 carbonate reservoir in the Hassi R'Mel field, Algeria, where conventional hydrochloric acid proves insufficient due to its rapid reaction rate and limited penetration depth. Laboratory dissolution experiments conducted on dolomite and calcite samples confirmed that OPR Fresh exhibits significantly superior retardation capabilities over conventional HCl, maintaining sustained acid activity and enabling deeper wormhole propagation. These findings were validated through a field treatment executed via coiled tubing, which resulted in a remarkable improvement in well performance, with the skin factor shifting from a heavily damaged positive value to a stimulated negative state, accompanied by significant gains in both permeability and hydrocarbon production. The results confirm that OPR technology is an effective and operationally viable solution for carbonate reservoir stimulation in the Hassi R'Mel field.