Integrated Study on Wara Prospectivity in Khashman Area, Kuwait
Dey, Arun K.*1; Chakrabarti, Bhaskar 1; Ye, Lin 1; Al-Wadi, Meshal 1; Abu- Hebiel, Hanan 1; Dashti, Jalal M.1
(1) Exploration, Kuwait Oil Company, Ahmadi, Kuwait.
Technological advancement along with new concept and continuous collection of geo-scientific information necessitate a fresh approach to re-assess the hydrocarbon potential of the areas where exploration started in the middle of last century but are yet to be fully explored. Khashman is such an area where exploration history dates back to early 60s and the presence of hydrocarbon in Wara Formation of Middle Cretaceous age has been confirmed from exploratory drilling but the formation is yet to emerge out as a prolific producer. Present paper deals with the re-evaluation of Wara prospectivity in Khashman area.
Pre-Stacked Time Migration processed seismic data along with subsurface information obtained from eight wells drilled on Khashman structure are the data set for this study. Sparse subsurface information and evaluation of hydrocarbon in drilled wells on the basis of technology available during 60s and 80s possess main challenges in the present work.
Volume based seismic attribute study like Most Positive Curvature, Dip Corrected Structure etc. reveals the presence of three sets of fault viz, NW-SE, ENE-WSW and E-W. The oldest set is NW-SE along which small culminations of Khashman structure are aligned and the youngest is strike slip E-W set. This complex fault architecture divides the area into several blocks.
Compartmentalization nature is evidenced from the presence of different Oil Water Contacts in different blocks. A picture on regional seismic facies distribution was extracted from phase studies in frequency domain at the reservoir interval. Integration of seismic facies with litho-facies interpreted from core and log studies confirm the presence of two depositional units in Wara Formation - Delta to Coastal Plain at bottom and Fluvial to Estuarine at top. Facies probability map indicates thickening of deltaic deposit towards N/NE and its gradual pinching out into coastal plain towards S/SW. Petrophysical analysis reveals the development of best reservoir quality in fluvial part towards S/SW where effective porosity ranges from 15 to 25% and water saturation from 30 to 40%.
The study has accreted more drillable reserve and thus enhanced the prospectivity of Wara Formation. It also leads to identify several prospects in different blocks. It has demonstrated the necessity of continuous revision of partially explored areas for reassessment of hydrocarbon prospects with the help of latest data sets, experiences, concepts and advanced technology.
AAPG Search and Discovery Article #90141©2012, GEO-2012, 10th Middle East Geosciences Conference and Exhibition, 4-7 March 2012, Manama, Bahrain