EXPERIMENTAL SIMULATION AND REMEDIATION OFTHE WATER BLOCK PHENOMENON IN LOW PERMEABILITY RESERVOIRS

Abstract

Water block is defined by water entrapment after drilling intervention operations when using water-based mud, completion, workover or stimulation in a low permeability reservoir. Increased water saturation in the pore space blocks the flow of oil and gas from the reservoir to the well. Water flow and its influence on oil threshold pressure were evaluated with constant pressure injection. Products including alcohols and chemical surfactants were used to reduce water saturation, capillary pressure by decreasing interfacial tension and reverse rock wettability by adsorption. As a consequence, low irreducible water saturation estimated at 30℅ at a given reservoir pressure gradient (1173 hPa) will be generated. The development of a model simulating the phenomenon as well as the study of the state of the well "HGANE2" allows to highlight the effect of this phenomenon on the productivity with a recovery of 400 (l/h) of water with permeabilities 1 115 (D), 1 476 (D), 1171(D).