New Sequence Stratigraphic Model for the Burgan, Mauddud and Wara Formations of Greater Burgan Field, Kuwait

AL-Enezi, Bashar ¹; Abdullah, Farida ¹; Burman, Kishore ¹; Datta, Kalyanbrata ¹; Al-Enezi, Hamdah ¹; Legurroue, Erwan ²; Filak, Jean-Michel ²; Murat, Bruno ²; Rousse, Stephane ²; Peysson, Alexandre ²
(1) kuwait oil company, Ahmadi, Kuwait. (2) Beicip-Franlab, Rueil-Malmaison, France.

The late Albian to early Cenomanian Burgan-Wara Formations from Southeast Kuwait constitutes the largest siliciclastic oil reservoir on earth. The sedimentology and stratigraphy of Greater Burgan field is reviewed here in terms of depositional environment and relation to global eustatic changes. An updated reservoir model has been built on a sequence stratigraphic framework from 980 wells, backed by sedimentological analyses, chemostratigraphy and biostratigraphy.

The Burgan, Mauddud and Wara Formations are represented by four 3rd order cycles in a coastal regime, with the lower most cycle and the overlying rising hemicycle representing the Burgan Formation.

The lowermost cycle comprising of stacked braided channels passes upward to tidal channel sandstones and heteroliths. Eventually a wave ravinement surface leading to a maximum flooding surface is recorded in tidal/bay to offshore environment. The regressive part of the cycle is constituted of tidal channels and bars.

The top of the second cycle, manifest as grainstone dominated carbonate platform, represents the Mauddud Formation, with the top karstified owing to late Albian / Cenomanian sea level drop. The third cycle is represented by homogenous compact offshore shales of Wara formation overlain by the coarse fluvio-tidal siliciclastic deposition representing the regressive stage of this 3rd order cycle.

The fourth transgressive hemicycle leading to the global Cenomanian / Turonian climatic optimum is marked by transgressive Sandstones in the upper part of Wara sands, culminating in deposition of Ahmadi shales. 4th order cyclicity is denoted by Marine transgressions, especially in the Northeastern part of the field.

Mapping of these sequences was aided by local sea-level curve and paleogeographic maps which helped decipher the Albian-Cenomanian coastal setting, contiguous to the neighboring Oman, Qatar and Saudi Arabia. The new Sequence Stratigraphic framework has a huge impact on the reservoir management of this giant field.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.