The increasing demand for energy in the world and the current status of the oil price are two important issues that drive the industry to re-look the unconventional sources witch can be form of heavy/ extra-heavy black oil and/or exist in deep, over pressured fractures carbonate source rocks. Exploration and production from these kinds of reservoirs, in the past, have not been economically feasible. In this communication, a successful case study on a heavy/extra-heavy oil field is presented and the techniques and challenges behind the exploration and production from highly fractured carbonate Bangestan reservoirs are discussed. The field is a giant structure located in the South West Iran and in the coast of Persian Gulf. It's a symmetrical anticline with 90 Km length and 16 Km width in the surface with about 3.6 billions barrels of initial oil in place and 10-16° API heavy oil. The pressure is 1408 psi at 1119 mdd (measured drill depth) and heavy oil didn't naturally flow to the surface. Exploration of the field carried out for evaluation of gas reservoirs in 1959 and a total of 5 wells have been drilled on this structure, wells number 6 and 7 were drilled in 1984 & 1985 for heavy oil evaluation in shallower formation. A 3D seismic and Side View Seismic Location (SVSL) carried out on this field. The swabbing operation then was performed for one well to identify property of rock and fluid in order to design pilot surface facility. The challenges and techniques employed on this field development including geological study, drilling operation, reservoir characterization and various techniques of production summarized in this paper and optimized production method to lifting this heavy oil to surface is described.

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