Sequence stratigraphy and reservoir characterization of the 2nd eocene dolomite reservoir, wafra field, divided zone, Kuwait-Saudi Arabia
Authors: Wani, M.R. and Al-Kabli, S.K.
Journal: SPE Middle East Oil and Gas Show and Conference, MEOS, Proceedings
Pages: 145-162
DOI: 10.2118/92827-ms
Abstract:The 2nd Eocene dolomite reservoir is one of the major producers in the giant Wafra Field of the Divided Zone between Kuwait and Saudi Arabia. The reservoir is of Paleocene age and occurs in the Tertiary Umm Er Radhuma Formation. The reservoir has been producing since late 1950's primarily under depletion drive. Recoveries, however, remain poor (about 5% of OIIP) mainly due to low-gravity oil and reservoir heterogeneity. A geological model that better defines reservoir heterogeneity is a pre-requisite for evaluating and implementing EOR techniques. Primary porosity in subtidal dolomitized carbonates associated with evaporites, as well as its later modification by dolomitization, dissolution and cementation, typically occurs in multiple zones formed within shallowing upward cycles. This paper attempts to identify such high frequency cycles in the Wafra 2nd Eocene Reservoir and place them in a sequence stratigraphic framework. Based on core analysis, and well log correlations in more than 300 wells, eight high frequency cycles further divided into 15 'zones' are recognized. This zonation helps to define the better and poorer reservoir units and the intervening non-reservoirs in a systematic manner as it brings out the distribution of grain rich dolomites and evaporites, as well as the cyclicity of dissolution and cementation. This has helped in improving reservoir definition over the entire field and led to a more robust stochastic model. Copyright 2005, Society of Petroleum Engineers Inc.
Source: Scopus
Preferred by: Mohammad Wani