Changes

==Example of modeling oil generation==

==Example of modeling oil generation==

The figure on the following page shows the rock accumulation rates for the Green Canyon 166 No. 1 well as a histogram (lower graph) and as a set of burial history curves (upper graph). Using temperature data from exploration wells, Piggott and Pulham.<ref name=ch04r75>Piggott, N., Pulham, A., 1993, Sedimentation rate as the control on hydrocarbon sourcing, generation, and [[migration]] in the deepwater Gulf of Mexico: Proceedings, Gulf Coast Section SEPM 14th Annual Research conference, p. 179–191.</ref> calculated temperature thresholds for the accumulated stratigraphic section. Burial of potential marine [[source rock]] above a temperature of approximately [[temperature::100&deg;C]] could initiate generation of oil.

File:Sedimentary-basin-analysis_fig4-33.png|{{figure number|5}}Rock accumulation rates for the Green Canyon 166 No. 1 well as a histogram (lower graph) and as a set of burial history curves (upper graph).

File:Sedimentary-basin-analysis_fig4-5.png|{{figure number|6}}

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The dominant hydrocarbon type in the Green Canyon area is associated with hydrocarbon family 6 (Figure 4-5), suggesting a Jurassic source rock. This source rock is indicated by the diamond labeled S and the shaded stratigraphic intervals. Based on the calculation of Piggott and Pulham<ref name=ch04r75 />), using BP Exploration's Theta [[Modeling]], generation of significant oil from a Jurassic source rock may have begun approximately 6 Ma in the Green Canyon 166 No. 1 well area when the Jurassic source rock was buried below [[depth::5000 m]] and above a temperature of [[temperature::120&deg;C]], the threshold for significant oil generation (see “[[Petroleum system]]s”).

 

The dominant hydrocarbon type in the Green Canyon area is associated with hydrocarbon family 6 ([[:File:Sedimentary-basin-analysis_fig4-5.png|Figure 6]]), suggesting a Jurassic source rock. This source rock is indicated by the diamond labeled S and the shaded stratigraphic intervals. Based on the calculation of Piggott and Pulham<ref name=ch04r75 />), using BP Exploration's Theta [[Modeling]], generation of significant oil from a Jurassic source rock may have begun approximately 6 Ma in the Green Canyon 166 No. 1 well area when the Jurassic source rock was buried below [[depth::5000 m]] and above a temperature of [[temperature::120&deg;C]], the threshold for significant oil generation (see “[[Petroleum system]]s”).

These calculations of rock accumulation and source rock maturation rates are dependent on good age models. Biostratigraphic data are the primary correlation tools in the GOM basin, as in most basins. Considerable care must be used in correlating basin bioevents to the global geologic time scale. The methodology for and problem of such correlations are discussed in Armentrout and Clement<ref name=ch04r10>Armentrout, J., M., Clement, J., F., 1990, Biostratigraphic calibration of depositional cycles: a case study in High Island–Galveston–East Breaks areas, offshore Texas: Proceedings, Gulf Coast Section SEPM 11th Annual Research Conference, p. 21–51.</ref> and Armentrout<ref name=ch04r7>Armentrout, J., M., 1991, Paleontological constraints on depositional modeling: examples of integration of biostratigraphy and seismic stratigraphy, Pliocene–Pleistocene, Gulf of Mexico, in Weimer, P., Link, M., H., eds., Seismic Facies and Sedimentary Processes of Submarine Fans and Turbidite Systems: New York, Springer-Verlag, p. 137–170.</ref><ref name=ch04r9>Armentrout, J., M., 1996, High-resolution sequence biostratigraphy: examples from the Gulf of Mexico Plio–Pleistocene, in Howell, J., Aiken, J., eds., High Resolution Sequence stratigraphy: Innovations and Applications: The Geological Society of London Special Publication 104, p. 65–86.</ref>

These calculations of rock accumulation and source rock maturation rates are dependent on good age models. Biostratigraphic data are the primary correlation tools in the GOM basin, as in most basins. Considerable care must be used in correlating basin bioevents to the global geologic time scale. The methodology for and problem of such correlations are discussed in Armentrout and Clement<ref name=ch04r10>Armentrout, J., M., Clement, J., F., 1990, Biostratigraphic calibration of depositional cycles: a case study in High Island–Galveston–East Breaks areas, offshore Texas: Proceedings, Gulf Coast Section SEPM 11th Annual Research Conference, p. 21–51.</ref> and Armentrout<ref name=ch04r7>Armentrout, J., M., 1991, Paleontological constraints on depositional modeling: examples of integration of biostratigraphy and seismic stratigraphy, Pliocene–Pleistocene, Gulf of Mexico, in Weimer, P., Link, M., H., eds., Seismic Facies and Sedimentary Processes of Submarine Fans and Turbidite Systems: New York, Springer-Verlag, p. 137–170.</ref><ref name=ch04r9>Armentrout, J., M., 1996, High-resolution sequence biostratigraphy: examples from the Gulf of Mexico Plio–Pleistocene, in Howell, J., Aiken, J., eds., High Resolution Sequence stratigraphy: Innovations and Applications: The Geological Society of London Special Publication 104, p. 65–86.</ref>