--> Abstract: Light Oil Production From An Unconventional Fractured Jurassic Carbonate Source Rock Reservoir, Kuwait, by M. Al-Jadi, R. B. Macdonald, E. C. Reji, D. P. Frost, J. C. Goff, A. J. Hill, A. J. C. Hogg, A. J. Barwise, and D. T. Needham; #90928 (1999).

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AL-JADI, M1, R. B. MacDONALD1, and E. C. REJI1, D. P. FROST2, J. C. GOFF2, A. J. HILL2, A. J. C. HOGG2, A. J. BARWISE3, and D. T. NEEDHAM3
1Kuwait Oil Company, Ahmadi, Kuwait
2
BP Kuwait, Ltd
3BP Exploration, Sunbury, UK

Abstract: Light Oil Production from an Unconventional Fractured Jurassic Carbonate Source Rock Reservoir, Kuwait

The Najmah/Sargelu Formation is a very rich, Middle Jurassic carbonate source rock which extends regionally across Kuwait and into surrounding areas. Geochemical analysis and thermal modelling show that the formation is still actively generating light (40 degree API) oil, some 90% of which has been retained, sealed by a thick salt caprock above and shales below. In West Kuwait, vertical wells in the Najmah/Sargelu produce light oil from fractures formed by a combination of folding and very high fluid pressures (13,000 psi). Fractures range from microfractures through closely spaced vertical hairline fractures; 1- 5ft bedding-confined vertical fractures; and large, vertical fractures cutting bed boundaries. The large fractures are oriented both parallel and orthogonal to the axes of Late Cretaceous folds. The abundant E-W hairline fractures probably formed when pore pressure exceeded the minimum horizontal stress (during peak oil generation) possibly reactivated during late Tertiary uplift. Surveillance data show that although depletion of the fracture system is rapid, slow recharge of the fracture network is occurring.

Horizontal development wells are planned to realise reserves and maximize recovery from the Najmah/Sargelu. Technologies being developed to support this include; drilling techniques to allow for long reservoir sections in fracture systems at extreme overpressures; and seismic imaging to identify fracture networks and optimize well targeting. Successfully implemented, these will open up the regional potential of this unconventional play.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas