Outcrop analogues for reservoir-scale conical intrusion

Sand intrusions represent an unconventional class of hydrocarbon traps and an emerging play in some major petroleum provinces (e.g. North Sea, West Africa). The most common seismic expression of sand remobilization processes and intrusion are conical-shaped amplitude anomalies commonly defined as conical injections. The latter may occur either as isolated units or clusters of conical features and have a bowl- or cup-like 3D geometry with a circular to horse-shoe shaped horizontal section (500-1500 m in diameter) and a V-like cross section. Outcrop analogues for conical intrusions are for the first time documented from the Panoche Giant Injection Complex (California, USA). This injection complex is characterised by the occurrence of sills, low-angle dykes and dyke swarms, which are arranged to form injected units with a semi-elliptical to horse-shoe geometry in plan view and V- or U-shaped cross section. These features are 500 to 1.5 km wide and in some cases cut vertically through more than 250 m of host rock.