Petroleum Migration, Faults and Overpressure, Part I: Calibrating Basin Modelling Using Petroleum in Traps - A Review

Abstract

the existence of oil or gas in both present-day and palaeo-accumulations of petroleum.Trapped petroleum represents an excellent source of information about hydrocarbon generation, expulsion, migration and accumulation, and the analysis of reservoired petroleum is a key tool in hydrocarbon exploration. Most geological information relates to the static rock framework, but oil which has moved through rock strata contains within it unique information for example on carrier interconnectivity and migration directions. Migrated petroleum also provides information on both source rock facies and temperatures of maturation and expulsion. In addition, physical changes which affected the petroleum during the migration process are preserved as geochemical "fingerprints"; these changes can be interpreted in terms of the mixing of different petroleums in a trap, leakage from the trap, biodegradation and mode of migration. Most processes affecting petroleum during migration and in a trap, whether they are biochemical, physical or This paper considers the principles of deciphering basin-scale hydrocarbon migration patterns using the geochemical information which is present in trapped petroleum. Petroleum accumulations in subsiding basins can be thought of as "data archives" within which stored information can help us to understand aspects of hydrocarbon formation and migration. This information can impart a time-resolved picture of hydrocarbon migration in a basin in response to processes associated with progressive burial, particularly in the context of the occurrence and periodic activity of faults.This review, which includes a series of tentative models of migration-related processes in the extensional Halten Terrace area, offshore mid-Norway, illustrates how we can use information from the migrating mobile hydrocarbon phase to improve our knowledge of the static geological system. Of particular importance is the role of sub-seismic heterogeneities and faults in controlling migration processes. We focus on how the secondary migration process can be enhanced in a multi-source rock basin such as the Halten Terrace, thereby increasing prospectivity.

Organic Geochemistry of Barents Sea Petroleum: Thermal Maturity and Alteration and Mixing Processes in Oils and Condensates

“…The ratio of the tricyclic terpanes C 23 -C 29 (TRI) relative to the C 30 αβ-hopane increases during maturation, due to the greater generation rate of tricyclics compared to hopanes at elevated maturities or differences in thermal stabilities (Aquino Neto et al, 1982;Farrimond et al, 1998;Peters et al, 2005;van Graas, 1990). However, Karlsen et al (2004) and Karlsen and Skeie (2006) found that this ratio may be controlled by the GOR of the petroleum due to PVT changes during migration (cf. England and Mackenzie, 1989).…”

“…Thus, any previously reservoired and lower maturity oil at this location appears to have been displaced by the later charge (cf. Gussow, 1954;Karlsen and Skeie, 2006;Sales, 1997). This interpretation implies ongoing lateral migration of hydrocarbons from the Tromsø Basin to the western part of the Hammerfest Basin (Fig.…”

Thermal maturity, hydrocarbon potential and kerogen type of some Triassic–Lower Cretaceous sediments from the SW Barents Sea and Svalbard

“…Dahl and Speers, 1986;Karlsen et al, 1995;Leythaeuser and Rückheim, 1989;Tissot and Welte, 1984). A number of studies, devoted to understanding the reasons and consequences of diversities in petroleum composition, have already been undertaken long ago (Bailey et al, 1973a;Bailey et al, 1973b;Dahl and Speers, 1986;Espach and Fry, 1951;Evans et al, 1971;Hirschberg, 1988;Hunt, 1979;Justwan and Dahl, 2005;Karlsen et al, 1995;Karlsen and Skeie, 2006;Milner et al, 1977;Sage and Lacey, 1939;Tissot and Welte, 1984;Tyson, 1995). These studies have revealed that the factors that cause heterogeneities in petroleum composition in reservoirs can roughly be related to 1) variations in source rock organic facies and source rock maturity and 2) secondary alteration processes.…”

“…Therefore, oil and gas generally accumulate in the structurally highest part of the trap, provided that further movement is stopped by cap rocks. Still, most oil and gas will never reach the trap to form commercial accumulations but remains in the secondary migration pathways and petroleum will potentially also migrate to the surface as seeps or eventually become exhumed as in the case of Alberta Tar sands (England, 1994;Karlsen and Skeie, 2006). If buried deeper conversion of reservoired petroleum to graphite is likely.…”

Factors Controlling Hydrocarbon Reservoir Formation and Distribution and Prediction of Favourable Areas in the Jurassic Toutunhe Formation in the Fudong Slope, Junggar Basin, China

“…In addition, the hydrocarbon show thickness is positively correlated with the sandstone thickness, with a correlation coefficient (R 2 ) of 0.6701 (Figure 8b). Hydrocarbon migration and accumulation were significantly affected by the physical properties of the reservoir rocks, such as the porosity, permeability, sand ratio and sandstone thickness (Karlsen and Skeie, 2006). In general, the oil-bearing capacity of the reservoir rocks rises with increases in the porosity, permeability, sand ratio and sandstone thickness (Pang et al, 2013).…”