Exploration Insights September 2020 | Page 9

Exploration Insights | 9 Petroleum System Index Number of reservoirs Simpson Bone Springs 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 way, higher risk petroleum systems can be easily identified, and a preliminary understanding of their limitations can be revealed. Intra-Basinal Variability © 2020 Halliburton Petroleum System Index Cisuralian Mississippian Late Devonian Late Ordovician Exceptional >50,000 MMBOE Figure 5> A cross plot of the holistic petroleum system index score and the number of reservoirs charged by studied petroleum systems in the Permian Basin. The schema can easily identify variability within the petroleum systems of a given basin. Early Permian, Early Carboniferous, Late Devonian, and Ordovician petroleum systems occur in the Permian Basin (Figure 2). Collectively, these systems result in one of the most prolific oil producing regions on Earth. It is no surprise that three of these petroleum systems (the Early Permian Wolfcamp, the Late Devonian Woodford, and the Early Carboniferous Barnett) have excellent qualities. They also have excellent holistic petroleum system index scores (Figure 5). These excellent scores are not replicated in the Cisuralian (early Permian) Bone Springs and Ordovician Simpson petroleum systems, which are of significantly lower quality (Figure 5). This example highlights the ability of the index to discriminate between different petroleum systems within a basin, and identify the truly exceptional ones, and the ones with greater associated risk. Comparing the Qualities of Petroleum Systems Globally Unique insights into the nature of petroleum systems can be gained through this global database of petroleum systems, and by utilizing the hierarchical index that we have defined. Three groupings of petroleum systems were defined when the average scores of petroleum system processes were plotted against the average scores of petroleum system elements, globally (Figure 6). 1 0.95 Element Enhanced High Quality Process Enhanced 0.9 0.85 Petroleum System Process Index 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 © 2020 Halliburton 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Petroleum System Element Index Figure 6> A cross plot of the petroleum system element index score against the petroleum system process index score for the global population of basins. This plot is divided into three domains: those where elements enhance the index score; those where processes enhance the index score; and those where both are of high quality.