M. Ashley Bigge¹

(1) Fluid Inclusion Technologies Inc, Tulsa, OK

ABSTRACT: The Application of Fluid Inclusion Analyses and Diagenetic Modeling in the Assessment of Reservoir History in Alwyn Field, North Sea

The purpose of the Alwyn field study was to evaluate and refine the pressure evolution and fluid composition evolution of the reservoirs throughout the geological past. The aim was to integrate past studies on the pressure regime and fluid evolution experienced in the Alwyn field (e.g. Jourdan et al, 1987) with fluid inclusion analyses. These analyses were carried out using the techniques of Confocal Laser Scanning Microscopy and PVT modeling in combination with diagenetic assessment techniques and SEM cathodoluminescence to precisely put into context the fluid inclusion genesis.

The fluid inclusions from two associated wells have been analyzed. The first, 3/9a-6, contained at present day a black oil in the Brent formation, while 3/9a-5 contained a gas condensate present day in the Statfjord formation. Each of these reservoirs had individually distinct pressure, temperature and chemical histories. This new information was then incorporated into an exemplar model in an effort to produce a consistent history of hydrocarbon and aqueous fluid evolution and emplacement over geological time (leading to the present day situation).

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado