A Reservoir Optimization Study—El Bunduq Field, Abu Dhabi, Qatar

Abstract

El Bunduq reservoir is located in the offshore area of Abu Dhabi and Qatar. The field was shut-in in July 1979 due to production with high gas-oi 1 ratios. Pressure differences of 200-400 psi between the flanks and the central part of the reservoir were sti 11 present almost four years after the field was shut-in. A comprehensive reservoir engineering study determined that the reasons for this behavior were the deteriorating qualities of the reservoir rock downstructure and the presence of a tar mat around the field.After the field behavior was history matched, model studies of a representative sector of the field indicated that peripheral waterflooding would recover 1 ess than 15 percent of the 001 Pin a peri od of 30 years.However, pattern injection recoveries were calculated to be at least twice as high.Several full field alternatives were investigated to optimize the development of the reservoir under a pattern waterflood. This paper summarizes the various studies that led to the acceptance of the idea of pattern development over peripheral injection, as a result of the unique characteristics of this field.

The Case for Early Generation and Accumulation of Oil

“…In the Minagish field, Kuwait, and the El Bunduq field, Qatar, basal "tar mats" in the Lower Cretaceous Minagish oolite and Jurassic Arab D dolomite, respectively, are folded (El-Aouar and Rasool, 1970;Bashbush et al, 1983).…”

An Experimental Study for Enhancing the Recovery Factor of Tar Barrier Heterogeneous Reservoirs

“…This leads to an alarming increase in gas/oil ratio during the primary stage of depletion which has been the case with Minagish reservoir in Kuwait [1]. Another such example is El Bundug reservoir in Qatar [7]. In other situations where the tar has some mobility or thins out at some location, a breakdown of tarmat may occur as a result of the buildup of large pressure differentials across the tar layer leading to severe water conning.…”