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Integrated whole-rock trace element geochemistry and heavy mineral chemistry studies; aids to the correlation of continental red-bed reservoirs in the Beryl Field, UK North Sea
- Source: Petroleum Geoscience, Volume 4, Issue 1, Feb 1998, p. 7 - 16
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Abstract
Correlating continental red-bed successions in the sub-surface is a common problem for the hydrocarbon industry. These successions are typically barren of fauna and often monotonous, leading to non-diagnostic wire-line log signatures. A high-resolution, high precision study of detrital garnet chemistry within Triassic reservoir sandstones from the Beryl Field of the North Sea failed to subdivide the sequence satisfactorily. However, the whole-rock concentrations of immobile trace elements such as Zr, Nb and Cr can be shown to be controlled primarily by the abundances of the heavy minerals zircon, rutile and chrome-spinel, respectively. The chemistry of detrital rutile and chrome spinel varies widely within any one sample, implying that the whole-rock concentrations of Nb and Cr are also a function of the chemistry of these heavy minerals. Having calibrated a type well with a detailed mineralogical and geochemical study, it was possible to correlate between wells using whole-rock geochemical cross-plots.