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7th Middle East Geosciences Conference and Exhibition
Manama, Bahrain
March 27-29, 2006
1 KOC Exploration Department, Ahmadi, Kuwait, [email protected]
2 BEICIP-FRANLAB, Rueil Malmaison, France
The entire Jurassic section and some areas of the Lower Cretaceous section in onshore Kuwait are characterized by high
overpressures, well above the hydrostatic regime
. This pattern extends apparently down to the Triassic and Paleozoic
section.
The understanding of the pressure regime
and its causes is important for pressure prediction before drilling as well as for
HC exploration, as pressure drives the flow of HC.
The pressure regime
has been investigated through a review of available pressure data (well tests, mud weights) and an
integrated 3D basin modelling study, using IFP Temis package.
A consistent pressure model has been developed, including: 1. the presence of tight shales in Ratawi fm, in the N and NW
Kuwait, responsible for overpressure in the Lower Cretaceous; 2. the presence of an impervious fault
corridor to the N,
separating hydrodynamically the Sabriyah and N Rhaudatain fields in the Cretaceous; 3. the regional extend of very low
permeability Gotnia salt, which acts as a pressure barrier throughout Kuwait, locally incised by poorly permeable faulted
areas (E and W of Burgan), acting as “security valves” for the overpressure
regime
, but allowing the hydrocarbon to leak
into the Cretaceous; 4. the existence of lateral barriers within the Jurassic in NW Kuwait, isolating Mutriba and Kra Al Maru
area from the Jurassic of N, E and W Kuwait which appear to be relatively well connected.
The pressure model characteristics in terms of Permeabilities related to the lithologies will be presented, together with its prediction for drilling depending on the geological context.