Minagish Formation - A Potential Unconventional Play in Offshore Kuwait

Hussain, Fida ¹; Al-Kandary, Ahmad ¹; Husain, Riyasat ¹; Prakash, Anand ¹; Rinaldi, Mulyono ¹
(1) Exploration, Kuwait Oil Company, Kuwait, Kuwait.

Offshore Kuwait lies in the northwestern extremity of the Arabian Gulf. It is not comprehensively explored and only few wells have been drilled to probe Cretaceous prospects with majority of them penetrating Minagish Formation of Lower Cretaceous age. This formation is oil bearing in Kuwait Bay located in western part of offshore Kuwait and comes under the category of tight reservoir with matrix porosities varying between 3-4 % and permeability in the range of 0.01-1.5 millidarcy. The depositional environments, distribution and quality of reservoir facies, and structural styles have been analyzed to identify areas of hydrocarbon prospectivity in offshore Kuwait.

Minagish Formation of Berriasian-Valinginian age is deposited under a transgressive system tract regime in a proximal to distal outer ramp to basinal setting and comprises wackestone, packestone and argillaceous rich mudstone with shale interbeds. The formation is subdivided into three members namely Lower, Middle and Upper based on the correlation with its type area located in southern onshore Kuwait. The lower member comprises of dominantly argillaceous mudstone with rare wackestone deposited in a distal outer ramp to basinal setting. The middle member consists of wackestone, packestone with rare mudstone deposited in a proximal to distal outer ramp environment. The equivalent of this member in the onshore is represented by oolitic grainstone facies having excellent porosity and permeability. The upper member consists of argillaceous mudstones and wackestones reflecting deposition in a distal outer ramp and basinal setting. This member is oil bearing in offshore Kuwait and has given good production despite low porosity and matrix permeability. The structure maps prepared at the top of Minagish Formation has brought out four way as well as fault closures and four major fault systems with possibility of natural fractures in their vicinity. These fractures are believed to have enhanced the reservoir permeability resulting in good production.

Kuwait Bay located on Kuwait Arch is characterized by tightly folded structures affected by diverse array of faults envisaged to be located over fracture corridors developed during Late Jurassic and reactivated episodically later. The formation holds promise for tight hydrocarbon prospectivity in this area. Seismic attribute analysis and Geo-mechanical modelling are key to the exploration and exploitation of this tight reservoir.

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