Generation and migration of oil in the Maturin Subbasin, Eastern Venezuelan Basin

Shelf petroleum system of the Columbus basin, offshore Trinidad, West Indies. I. Source rock, thermal history, and controls on product distribution

“…A combination of marine transgression caused by high eustatic sea level, local coastal upwelling, worldwide Albian to Coniacian anoxia, and high nutrient supply due to excessive fluvial runoff have been suggested as the primary factors controlling the accumulation and preservation of organic matter over this extensive area (Algar, 1998;Erlich et al, 1993;Rodrigues, 1987). Source rock and oil geochemical data within this belt implies a general eastward trend from a carbonatedominated source sequence in eastern Venezuela (Talukdar et al, 1987;A. Pepper, personal communication), through a transition zone across southern Trinidad (Requejo et al, 1994;Rodrigues, 1987), to a siliciclastic-dominated regime off southeastern Trinidad.…”

“…The organic-rich Gautier and Naparima Hill formations, which constitute a stratigraphic thickness in excess of 3000 ft (915 m) in southern Trinidad (Ablewhite & Higgins, 1968), are considered the source rocks for the majority of petroleum in Trinidad (Requejo, Wielchowsky, Klosterman, & Sassen, 1994;Rodrigues, 1987). These units are broadly agecorrelative to the La Luna, Querequal and other upper Cretaceous source rock sequences in Venezuela and adjacent areas (Talukdar, Gallango, & Ruggiero, 1987;Zumberge, 1984).…”

Application of the monoterpane ratio (MTR) to distinguish marine oils from terrigenous oils and infer depositional environment in northern Tarim Basin, China

“…As sources other than phytol may yield pristane and phytane (Larter et al, 1979(Larter et al, , 1983Chappe et al, 1982;Illich, 1983;Goossens et al, 1984;Rowland, 1990), Peters et al (2005) suggested that high Pr/Ph (> 3.0) indicates terrigenous organic matter input under oxic conditions while low values (< 0.8) typify anoxic, commonly hypersaline or carbonate environments. Pr/Ph values have been successfully used to distinguish non-marine oils from marine oils in numerous studies (Hughes, 1984;Moldowan et al, 1985;Talukdar et al, 1988).…”

Behavior of Re and Os during contact between an aqueous solution and oil: Consequences for the application of the Re–Os geochronometer to petroleum

“…Several authors, including Talukdar et al (1988), Cassini and Eglinton (1991) and Summa et al (2003), provide details on the geology and geochemistry of this type of oil. This heavy oil is diluted with n-alkanes to yield a blend with a higher API gravity.…”