Well-Based Shale Resource Assessment Using High Resolution Basin and Petroleum Systems Modeling

Abstract

Abstract We present a resource assessment from the Upper Bowland Shale, East Midlands, onshore UK, based on coupled petrophysical interpretation and high resolution basin and petroleum systems modeling (BPSM). In most past BPSM studies, the source rock was typically treated as a single formation with bulk properties, and intra-formational heterogeneities within the bulk rock were not taken into account. In the presented study, we have used a high resolution stratigraphy and geochemical data for the definition of intra-shale sweetspots and a quantitative volumetric assessment of oil and gas retained within the shale. Since a large part of the assumed oil and gas kitchen is relatively flat-lying and the vertical heterogeneity is considered more important than the lateral variations in facies, 1D basin and petroleum systems modeling is performed at a representative well location (Scaftworth B2). Petrophysical logs are computed and calibrated to core and cuttings as applicable and used in the modeling. Integrating a 14 component source rock kinetic, processes such as hydrocarbon generation and adsorption, intra-formational migration and expulsion are simulated at a meter scale. As a result of the modeling, prospective layers can be identified based on modeled free-phase oil and gas saturation and volume, adsorbed amounts, detailed composition as well as fluid properties (e.g., density, viscosity, and oil GOR and API). Such vertical "sweetspot units" can be used to define the intervals prospective for horizontal drilling and hydraulic fracturing.