Abstract: Importance of Geometry in Groundwater Systems--Examples from Hydrocarbon Exploitation, Minerals Genesis, and Environmental Protection

G. D. Couples, R. S. Haszeldine, D. Darby, C. G. Fleming, H. Lewis, C. McKeown, R. Stewart

Over the last few years, the basin analysis research program at the University of Glasgow has investigated the geohistory of a number of settings in which groundwaters play a key role. We have identified cases where groundwaters have: (A) been static for a long time; (B) undergone substantial motion and/or replacement; (C) carried heat; (D) transported solutes [with precipitation and/or leaching of diagenetic minerals or economic metals, or might disperse radioactive waste]; or (E) exerted an important mechanical influence [in overpressured cells]. Throughout these studies, the recurrent "theme" is that

of geometry--the geometry of the rocks, the geometry of the energy system(s), and the geometry (distribution) of fluid types.

In this talk we will use the results of several studies to emphasize the importance of geometric aspects in basin modelling. These projects include: (1) Carbonate concretions in Palaeocene sands localised due to mixing of hydrocarbons and influxing meteoric waters, with consequent degradation; (2) Several Jurassic reservoirs, illustrating a variety of hydrogeologic behaviors; (3) Locations and causes of overpressure in the Central Graben; (4) Identification and explanation of modern temperature anomalies in the Central Graben related to fluid flow; (5) Quantification of thermal and fluid budgets for Carboniferous mineralization in the Irish Midlands; and (6) Assessment of the hydrogeology of the proposed Sellafield nuclear waste repository.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994