The Distribution of Major Oil and Gas Reserves in Regional Basin Structures – An Example From the Powder River Basin, Wyoming, Usa

Abstract

The location and geographic distribution of oil and gas reserves within a producing basin often indicate that a remarkable concentration of reserves has taken place in a small area. The concentration of reserves is the result of secondary hydrocarbon migration, itself governed by the basin‐wide regional structure which was present at the time of migration. These factors permit the definition of the most prospective areas of a new basin or play at an early stage in the exploration cycle. Basic geochemical data are required for the definition of critical details of the effective generative depocentre, and regional geological‐geophysical data are required to establish regional structures near particular source‐bed levels, or near top Basement as the deepest prospective level. Other data commonly utilized in the early stages of exploration, such as basin classification schemes, reservoir bed studies and tectonic analyses, are rather less important in forward basin evaluation. A particularly clear example of the importance of the regional basement structure in the concentration of oil reserves exists in the Powder River Basin, Wyoming, USA. Cumulative oil production here was over 1.9 B brls** in 1984 from more than 460 oilfields and pools. However, 1.5 B brls (79% of the basin output) were produced from only 22 fields (4.7% of the number of fields and pools in the basin). It is also remarkable that all 22 major oilfields in the Powder River Basin are located on positive Bouguer gravity anomalies, which are expressions of deep basement irregularities. Regional lateral oil migration in the Powder River Basin appears to have utilized routes resulting from Laramide deformation (Late Cretaceous ‐ Paleocene). The resultant basin structure was accentuated by regional structural‐topographic anomalies, which became sites of major structural and stratigraphic traps. In this case regional gravity maps seem to show sufficient details of the deep structure for the accurate definition of major exploration targets. The Powder River Basin is thus an excellent example of the importance of regional geological and geophysical reconnaissance data aimed at, and available for, the definition of major migration pathways at an early stage of hydrocarbon exploration. When combined with geochemical data, such an approach will become the basis for forward exploration in all known basins.

The origin and distribution of crude oil in Zhu III sub-basin, Pearl River Mouth Basin, China

“…A C C E P T E D ACCEPTED MANUSCRIPT (Dembicki and Anderson, 1989;Hindle, 1989Hindle, , 1997Catalan et al, 1992;Thomas and Clouse, 1995), and structural morphology is the most important factor that controls the positions of petroleum migration pathways in sedimentary basins (Pratsch, 1983(Pratsch, , 1986(Pratsch, , 1994Hindle, 1997).…”

Preferential petroleum migration pathways in eastern Pearl River Mouth basin, offshore South China Sea

“…A number of workers believed that the migration pathways in heterogeneous carrier beds are primarily controlled by permeability heterogeneities, with petroleum preferentially migrating through carrier-bed portions with relatively high permeability (e.g., Bekele et al, 2002Bekele et al, , 1999Rhea et al, 1994). Many others believed that, even in heterogeneous carrier beds, the petroleum migration pathways are controlled largely by structural morphology (Hindle, 1997;Pratsch, 1994Pratsch, , 1988Pratsch, , 1986Pratsch, , 1983Momper and Williams, 1984).…”

“…Therefore, they are difficult to effectively predict because of complications with characterizing permeability heterogeneity related to the extent of fracture permeability and permeability alteration due to diagenesis (Bekele et al, 2002). Nevertheless, others believed that petroleum migration pathways are controlled largely by structural morphology (Hindle, 1997;Pratsch, 1994Pratsch, , 1988Pratsch, , 1986Pratsch, , 1983Momper and Williams, 1984), and modeling of petroleum migration pathways can be a powerful tool to reduce exploration risk (Hindle, 1999(Hindle, , 1997Hermans et al, 1992;Sylta, 1991).…”

Petroleum migration and accumulation in the Bozhong sub-basin, Bohai Bay basin, China: Significance of preferential petroleum migration pathways (PPMP) for the formation of large oilfields in lacustrine fault basins

“…The ''restrainingforce school'' considers the migration pathway as a sheetlike migrating petroleum front (Rhea et al, 1994), and believes that the positions of petroleum migration pathways are largely controlled by permeability heterogeneity of the carrier beds (e.g., Rhea et al, 1994;Bekele et al, 1999Bekele et al, , 2002 and are therefore difficult to effectively predict because of complications with characterizing permeability heterogeneity related to the extent of fracture permeability and permeability alteration due to diagenesis (Bekele et al, 2002). By contrast, the ''driving-force school'' views petroleum migration pathways as very restricted rivers or streams (Gussow, 1954(Gussow, , 1968Dembicki and Anderson, 1989;Catalan et al, 1992;Thomas and Clouse, 1995; Hindle, 1989Hindle, , 1997, and believes that the positions of petroleum migration pathways in sedimentary basins are controlled largely by structural morphology (Gussow, 1968;Momper, 1978;Momper and Williams, 1984;Pratsch, 1983Pratsch, , 1986Pratsch, , 1988Pratsch, , 1994Hindle, 1997), and believes that modeling of petroleum migration pathways can be a powerful tool to reduce exploration risk (Sylta, 1991;Hermans et al, 1992;Hindle, 1997Hindle, , 1999.…”