Reservoir characterization of the Burqan Formation sandstone from Midyan Basin, northwestern Saudi Arabia

Abstract

The Early Miocene sandstone of the Burqan Formation from Midyan Basin is considered an oil-bearing unit. The outcrops of this sandstone, which are exposed in the northwestern part of the basin, have been studied through field and laboratory-based investigations. During the field work, 81 surface samples were collected for reservoir characterization. Laboratory analyses were undertaken to determine the effect of the diagenesis on the reservoir quality using integrated sedimentological, petrological, and petrophysical analyses. According to these analyses, the sandstone of Burqan Formation is predominately subarkosic and sublitharenite in nature, medium to course grained in size, rounded to subangular in shape, and poor to moderately sorted. Porosity of the studied sandstone, which is both syndepositional and diagenetic in origin, has been determined as poor to very high, with an average value of 22.73%. The observed permeability is moderate to very high, with an average estimate of 2444.2 millidarcy. Cementation coupled with compaction had an important effect on the porosity destruction after sedimentation and burial. The reservoir quality of the studied sandstone is reduced by clay minerals (kaolinite and smectite), calcite, and silica cementations, but, on other hand, it is increased by alteration and dissolution of the unstable grains, in addition to partial dissolution of calcite cements. The potential of the studied sandstone to serve as a reservoir is strongly related to sandstone diagenesis. © TÜBİTAK.