Acid Fracturing Was Selected to Stimulate the Potential Production in Low Permeability Reservoirs in Ahdeb Oilfield, Iraq

Abstract

Abstract The low permeability reservoir of Ahdeb field discovered in the 80's, has more than 250 active wells with low initial production and rapid decline compared to other reservoirs. Matrix acidizing is the main stimulation method to recover and enhance production performance in Ahdeb oilfield, but short-distance deblocking acidizing can't communicate with the deep reservoir, and it is impossible to expand the effective seepage radius. Therefore, High reservoir heterogeneity, low permeability, poor pore pressure necessitates the move from conventional matrix stimulation to acid fracturing technology targeting better fracture conductivity and deep penetration for effective productivity and recovery enhancement. The acid fracturing feasibility research shows that the interlayer characteristics, lithologic barrier, stress barrier and oil-water relationship of the low permeability reservoirs are favorable for fracture initiation, expansion and geometry control. Acid fracturing is one of the best ways to stimulate the potential production in low-permeability reservoirs of the Ahdeb oilfield. The acid fracturing optimization includes fracture conductivity, fluid system and fracturing parameters. Pad acid fracturing and gel acid with multi-stage alternating and closed acid fracturing are the suitable technologies for low permeability reservoir stimulation. An experiment well has been simulated and designed, and the expected production increase is 1.5 times. Base on this paper's research, a wide-scale development strategy will be planned, and many wells will be stimulated for increase the production performance.