Source rocks facies

Source rock facies. Biomarker data from Magnolia fluids can be used to address the degree to which variations in source rock facies are responsible for or contribute to the heterogeneity of fluid properties discussed above. Sterane and hopane biomarkers of the Magnolia oils compare well with those described by Guzman-Vega Mello... 

Jones P. J. and Stump T. E. (1999) Depositional and tectonic setting of the Lower Silurian hydrocarbon source rock facies, central Saudi Arabia. AAPG Bull. 83, 314-332. 

Comet, P.A., and Eglinton, G (1987) The use of lipids as facies indicators. In Marine Petroleum Source Rocks. Geological Society Special Publication 26, 99-117. 

Several attempts have been made to integrate geochemical parameters into this framework of system tracts to assist in differentiating one facies from another. Potential source rocks can be found in all three system tracts, with the richest source rocks generally found in the condensed section within a TST. The best petroleum reservoirs are found in LST. With the use of geochemical data, the various system tracts in a sequence can be identified and therefore used to distinguish the location of both potential petroleum source rocks and reservoirs. 

Lambert M. W. (1993) Internal stratigraphy and organic facies of the Devonian-Mississippian Chattanooga (Woodford) Shale in Oklahoma and Kansas. In Source Rocks in a Sequence Stratigraphic Framework, AAPG Studies in Geology 37. American Association of Petroleum Geologists, Tulsa, OK. pp. 163-176. 

Mann U. and Stein R. (1997) Organic facies variations, source rock potential, and sea level changes in Cretaceous black shales of the Quebrada Ocal, upper Magdalena Valley, Columbia. Am. Assoc. Petrol. Geol. Bull. 81(4), 556-576. 

Component distributions are in effect perfectly exponential and, presuming the saturated and undersaturated oils to be derived from a uniform source facies, suggest their derivation from source rocks of different maturity (Thompson, 2002). Slope factors (SF, defined in Fig. 13 caption) of the remaining oil samples vary between the end member values of 1.07 and 1.14 and positively correlate with other maturity indicators. In contrast, the relatively high slope factors evidenced by the gas-condensate samples (1.12-1.27) do not correlate with any of the maturity-influenced indicators discussed above, suggesting that the gas-condensates are not a high maturity product. 

We have documented the close genetic relationship between the bitumen and petroleums in presently filled and drained traps and ascribe the minor variations that exist, not to source rocks other than the Spekk, but rather to east-to-west lateral systematic variations in terms of proximal to distal source rock organic-facies development of the Spekk Formation source rock. 

Compositional variations among the Silurian or Devonian oil samples might be caused by differences in source rock organic facies, thermal maturity, or other factors. Our ability to account for these differences is limited by the small number of samples in this study. 

The magnitude of porosity enhancement due to aluminosilicate grain dissolution in a reservoir and source-rock system depends on facies relationships, variations in original composition, formation of subsequent cements, availability of fluid conduits, fluid flux, and the proximity of organic-rich source rocks in hydrologic connection with the reservoir rock. In contrast, carbonate decementation and mass transfer apparently can occur on a scale larger than a specific reservoir and source-rock system (Schultz et al. 1989). 

Although the majority of attention in discussions on the origins of BIFs has been on the oxide facies, siderite facies rocks are equally important in many BIF sequences. Reaction of Fe(II)aq and dissolved carbonate with hematite to form siderite and magnetite has been hypothesized to be an important diagenetic process in marine basins during formation of some BIFs if sulfate contents were low (e.g., Klein and Beukes 1989 Beukes et al. 1990 Kaufman 1996 Sumner 1997). In Figure 18 we assume that Fe(II)aq was derived either from MOR sources or DIR, or a combination of the two, which reacted with ferric oxide precipitates to form magnetite or dissolved carbonate to produce siderite. 

Donald R. Baker. It seems to me that your results on the distribution of boron and gallium have important implications for the work of others who have concluded that these elements are depositional environmental indications. I wonder if the enrichment of these elements in nonmarine rocks of Pennsylvanian age in the eastern U.S. may simply reflect their proximity to the source area and not have any real bearing on the depositional environment. And conversely, the lower content of these elements reported for marine shales may be caused by deposition of these facies in areas far removed from the source areas. What is your opinion ... 

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