Rapid and integrated petroleum systems analysis with dynamic gas fraction and flexural reconstructions: Application to hydrocarbon charge and commodity risk.

The most time consuming and computationally intensive steps in petroleum systems analysis involve building heat flow boundary conditions that are consistent with regional geologic observations, solving the transient heat equation, and translating a range of hydrocarbon charge predictions from source intervals into prospect specific predictions that can be used for decision making in oil and gas exploration. Furthermore, three-dimensional regional flexure, which can have a significant impact on paleo-migration pathways, often is not included in the critical step of translating charge calculations into trap specific predictions due to the time-consuming nature of map preparation. In this paper, an efficient and integrated petroleum systems analysis (IPA) workflow is presented with a new fast, semi-analytical, decoupled approach for solving the transient heat equation that is fully integrated with a rapid inversion methodology for transient heat flow boundary conditions and a 3D regional flexural reconstruction that uses standard basin modeling inputs and requires little to no additional map preparation. A charge-to-trap model is also described that translates hydrocarbon expulsion calculations with dynamic parameterized gas fractions that vary with transformation ratio into trap specific predictions using flexurally restored migration polygons. This fully integrated and efficient approach enables rapid interactive investigation of uncertainty space and fast probabilistic modeling that is ideal for evaluating hydrocarbon charge and commodity risk in data-sparse frontier basins. The applicability of this approach is demonstrated for assessing charge and commodity risk with a case study from the Colorado Basin, Argentina, whereby two alternative hydrocarbon accumulation hypotheses that postulate that traps are filled to structural spill with undersaturated oil are tested for reservoirs located in the upper Colorado Formation that are charged by postulated Aptian and Neocomian source rocks. This application indicates that it is unlikely that the tested traps are filled to structural spill with undersaturated oil, and how incorrect conclusions on hydrocarbon commodity may be reached if 3D regional flexure is not considered during petroleum systems analysis. Finally, it is also shown how this integrated and efficient approach can be implemented with low-cost computational platforms such as Python Anaconda or in spreadsheet programs that empower modelers to rapidly translate their ideas into benchmarked prototypes that can be immediately leveraged by the geoscience community (www.github.com/eakneller/ipatoolkit3D). • We show a basin analysis workflow with 3D flexure, boundary condition inversion and a new efficient approach for solving the heat equation. • A hydrocarbon expulsion model with dynamic gas fractions and 3D flexure is presented enabling efficient oil and gas commodity predictions. • This new integrated and efficient approach enables rapid interactive investigation of uncertainty space and probabilistic modeling. • A case study from the Colorado Basin is presented showing the applicability of this approach and the importance of including 3D flexure. • Finally, we show how this optimized approach can be implemented with low-cost computational platforms. [ABSTRACT FROM AUTHOR]