Application of a sealing surface classification for stratigraphic related traps in the UK Central North Sea

Abstract

Abstract Traps can be categorized by defining the relationship of the seals with respect to the reservoir/seal bounding surface(s). Two major subdivisions provide the foundation of the classification; one-seal traps are structures which possess closed contours at the reservoir/seal interface, whereas poly-seal traps are those where closed contours at the reservoir/seal(s) interface do not exist or are inadequate to entirely close the trap on a single sealing surface; thus implicating the requirement of one or more base and/or lateral seals. The nature (conformable, unconformable, tectonic, facies change, waste zone) and combination of the seals essential to contain the hydrocarbon pool with respect to the one-seal and poly-seal distinction allow for further subdivisions of each of these classes. This publication catalogues a variety of Lower Cretaceous, Upper Jurassic and Tertiary stratigraphic related traps (stratigraphic and combination) from the Central North Sea with respect to fourteen applicable sealing-surface classes. The paper also provides a source for identifying and categorizing prospective stratigraphic related traps in accordance with documented field examples from the Central North Sea. In addition, the author demonstrates the scheme as a first-pass exploration tool to rank future portfolios of stratigraphically trapped prospects with respect to the trapping integrity/reliability of the sealing surface(s).