Methane emissions from petroleum bearing basins [article]

Luiyin Alejandro Berbesi, Brian Horsfield, Technische Universität Berlin, Technische Universität Berlin
2015
The main objectives of this study are to model the evolution of petroleum systems in different sedimentary basins and to quantify their associated methane leakage through geologic time. In this way, the study aims to contribute to the understanding of any link between petroleum-bearing basins and the Earth's climate evolution, and the main processes involved. The analyzed study areas are two Canadian basins: the Western Canada Sedimentary Basin (WCSB) and the Beaufort/Mackenzie Basin (BMB); and
more » ... ie Basin (BMB); and the Central Graben of the North Sea province. The methodology involves petroleum system modeling and analysis, mass balance approaches and comparison of results from the selected study areas against world-wide published data. Although the main focus is on thermogenic gas generation, migration, and leakage; other relevant processes taking place in the selected geological settings are addressed. In the case of the WCSB, a quantification of the microbial methane generation during the biodegradation of the original oils in Athabasca is carried out. In the case of the BMB, petroleum system modeling and analysis allows to assess the methane gas hydrate potential of the region. Maximum predicted thermogenic gas generation rates are in the order of 10E-2 (WCSB) to 10E-3 (BMB and Central Graben) Teragrams (1 Tg=10E12 g) per year. Biogenic methane could have been produced in the WCSB at rates of up to 10E-3–10E-2 Tg/yr, depending on assumption regarding the degradable oil mass. Modeling results suggest that gas leakage spread out over a large area, not concentrated or focused, and driven by generation in kitchen areas cannot take place at rates as those reported in the literature, regardless of the sedimentary basin size and carbon pool. Only the reservoir part of the petroleum systems is able to interact with the atmosphere at significant speed, and the mechanisms driving leakage are, by far, more relevant than the carbon inventory of sedimentary basins. It is proposed that future studies on the topic should concentrate in bas [...]
doi:10.14279/depositonce-4481 fatcat:j36qoirsqrd5nhdl2zsilygihu