No 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 high complexity of diagenetic facies and +hei~1 -*-*.1 . -----Au.-.w-eh.maaa .ffa,-t4"o V..-mrn+ . -..s..~--q...._-.A..~.=-=. "".. . quality can be monitored.A computer-based program haa been used for zonation of wells into electrofacies according to Reservoir quality in the Arab C fncreaaes log responses. The process determines a number of towards the crestal zone due to the occurrence clusters from similar log valuee. of lees anhydrite (F7, F8) in the carbonate facies. To ensure that the electrofacies obtained are geologically meaningful, log responses from key In the Arab D, porous electrofacies F3 and F5 wells were calibrated with geological facies from (porous and dolornitic mudstonea) are well cores. Input logs were selected accordingly.represented in the crestal part of the field but get very thin or pinch out towards the The creation of a data bank helped to obtain flanks. consistency in the twenty-six wells processed in El Bunduq field offshore Abu Dhabi/Qatar.