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

Abstract

AbstractTraps 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 trapsare structures which possess closed contours at the reservoir/seal interface, whereaspoly-seal trapsare 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).