World Geothermal Congress 2020+1
March - October, 2021

Fracturing in Basement Reservoir Rocks: Case Study of the Norwegian and Scottish Basements, Some Analogues for Deep Geothermal Reservoir

Sylvain LUBY, Yves GERAUD, Maelle BREMAUD, Preden YVONOU, Marc DIRAISON, Luca MATTIONI

[GeoRessources, France]

The occurrence of naturally fractured basement reservoirs has been known within the E&P industry for many years. However, despite their proven commercial success, basement reservoirs are a globally underexplored field for geothermal research, with some exceptions such as in Rhine Graben where several plays are under investigation. Fluids accumulations in basement rocks are usually restricted to fault zone however accumulations may also arise in igneous bodies that have been intruded into sedimentary successions. In this kind of ultra-tight reservoirs, fluids are essentially confined into porous fractures within, or near, fault zones or may migrate significant distances from faults if the open fracture network permits. Weathered zones of basement, usually confined to the upper reaches of the palaeobasement surface, sometimes provide areas of increased upside volumes and the same can apply to sections of hydrothermally altered basement. However, this may not always hold true if, for example, porosity has been later filled by cements or weathering products. Natural geological features present within basement can be divided into two main categories: lithological elements and structural elements. Lithological elements include features such as foliation, intrusions and lithological changes. Structural elements include fractures/joints, faults and breccias. Basement is commonly considered to be an impermeable part of a geological system, but this assumption does not hold for weathered and fractured bedrock. Even though weathering and fracturing are common features of bedrock, their characterization and their mutual relationships are still an under explored and challenging issue. For the purpose of characterizing Norwegian and Scottish basement, a lineament analyses were conducted on the two basements using high resolution DEM on a GIS software

        Topic: Geology Paper Number: 12194

         Session 8P: Poster 2 [Tuesday 11th May 2021, 11:00 pm] (UTC-8)
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