Heavy mineral suites in the Statfjord and Nansen Formations of the Brent Field, North Sea; a new tool for reservoir subdivision and correlation

Abstract

Heavy mineral data provide an independent basis for subdivision and correlation of the Statfjord-Nansen reservoir sequence in the Brent Field, UK North Sea. Because of its continental fluvial depositional environment, this sequence lacks a well-defined biostratigraphically-based correlation framework. Detailed well correlations are difficult because of the heterolithic nature of the reservoir and the lack of chronostratigraphically significant markers. Three major heavy mineral zones and a number of subzones have been established. These can be confidently correlated in cored sections across the Brent Field. The correlations made using the heavy mineral scheme generally parallel the boundaries between reservoir units, giving confidence to the current reservoir zonation and indicating that it has a sound geological basis. However, the mineralogical zonation of a crestal, faulted well, 211/ 29-D44 (BD44), differs significantly from the reservoir zonation. This illustrates the difficulties inherent in establishing field-wide correlations without support of independent correlation schemes.

Solubility measurements of synthetic neodymium monazite as a function of temperature at 2kbars, and aqueous neodymium speciation in equilibrium with monazite

“…This orthophosphate mineral with the formula (Ce, La, Nd, Th)PO 4 and a monoclinic structure, occurs as an accessory phase in granites, gneiss and pegmatites. Its relative resistance to chemical and physical weathering enable it to concentrate in alluvial deposits and beach sands (Read et al, 1987;Morton, 1992;Morton and Berge, 1995).…”

Garnet compositions in Scottish and Norwegian basement terrains: a framework for interpretation of North Sea sandstone provenance

“…Heavy mineral assemblages are known to be sensitive indicators of sediment provenance (see review by Mange and Maurer (1992)), and have been extensively used in investigations of North Sea sandstones from the Devonian to the Tertiary (Allen & Mange-Rajetzky, 1992;Hallsworth, Morton, & Dore, 1996;Morton & Berge, 1995;Preston et al, 1998). However, determination of sandstone provenance directly from heavy mineral data is not straightforward.…”

Využití gamaspektrometrie při studiu spodnobadenských sedimentů ve vrtu 2241_B Brno-Černá Pole

“…Poměr Th/K bývá v rámci psefitických sedimentů využíván jako indikátor minerálního složení klastů. Níz-ká hodnota tohoto poměru (sensu Rider 1996) ukazuje na relativně nízkou koncentraci Th v brněnských píscích, což lze spojit se zdrojovými horninami, případně depozičními procesy (e. g. Mange -Rajetzky 1995; Morton -Berge 1995;Morton -Hurst 1995).…”