Derisking of Unconventional Gas Opportunities: Application of Basin Modelling

Abstract

Unconventional Liquid Rich Shale (LRS) and shale gas (SG) plays are self-charged continuous systems relying on their indigenous organic matter as the source of hydrocarbons. The residual pore space of fine-grained organic rich sediments themselves or similarly tight deposits in their close vicinity act as the reservoirs. Pressure (P) and temperature (T) can significantly increase during burial of the sediments and can likewise undergo a substantial instant P but time-deferred T decrease during erosion and uplift. These changes in P and T strongly influence the phase behaviour of the generated and trapped hydrocarbons (HC), thereby affecting the retention capacity of the source rock, the HC flow properties, potential migration routes, and the predicted HC volumes initially in place (GIIP/OIIP). Shell's integrated Cauldron Shale Gas Simulator calculates resource density on a regional to basin scale, typically during the opportunity identification and screening phase of a project. Informed decision-making in exploring for unconventional opportunities relies on the integration of all available (i.e., sometimes scarce) data and their associated uncertainties for basin scale physical elements and processes into a working geologic model.