First Break - Volume 30, Issue 12, 2012

Neil R. Goulty and Agus M. Ramdhan outline the difficulties in pore pressure estimation when drilling exploration wells at depths where the temperature exceeds ~100°C.

O.A. Blaich, J.I. Faleide, M. Rieder, G.A. Ersdal and B.I. Thyberg describe how integration of long-offset seismic reflection data and inversion of seismic refraction first arrival traveltime shot-gathers improved geological interpretation of the Stappen High in the SW Barents Sea.

Ron Borsato, William Jones, Jennifer Greenhalgh, Mark Martin, Rick Roberson, Carlos Fontes, Paul Markwick and Andy Quallington, discuss why modern seismic data and more precise plate reconstructions allow better insight into the critical factors that make analogous features on unexplored conjugate margins a prospective target for exploration drilling.

Gregor Duval provides some graphic evidence of how broadband seismic data can unmask the hidden potential of the UK Continental Shelf.

Neil Hodgson reports on how recent 2D and 3D seismic in the Eastern Mediterranean suggests that assumptions about the geological history and hydrocarbon plays may need some revision.

Ruud Weijermars and Joost van der Linden outline a new reality for shale gas plays where even sweet spots may become sub-economic when gas prices collapse. The North American shale-gas bonanza is reviewed and sweet spot sensitivity to gas price volatility is illustrated for the Haynesville shale play. The second part of this article will follow in the January issue.

Pete Dotsey introduces a methodology developed by Ian Deighton1 for basin temperature modelling that utilizes a large volume of properly indexed and QC’d bottom-hole temperature data for a basin or area. Results from the Delaware Basin illustrate the method.

A proposed subdivision of offshore West Greenland into four provinces is presented on the basis of regional variations in geological development, especially during the Cainozoic. The four provinces are from north to south: Baffin Bay, Disko West, Nuuk West, and Cape Farewell. In these provinces, play factors such as the petroleum-charge system, reservoir-seal system, and trap type must be viewed in close relation to two key processes: the influence of volcanic activity during the Palaeogene and Cainozoic exhumation. Caution is advised in using analogues and play evaluations across provinces without adjusting for key differences in geological evolution.

RGB colour blending is a powerful technique of co-visualization of different band-limited magnitude volumes created by frequency decomposition. The aims of this study were to investigate the impact of changes in geometry and acoustic impedance on what we observe in a blend of frequency magnitude volumes, and to examine how sensitive different methods of frequency decomposition are to these variations. We present a comparison of frequency decomposition methods applied to the Hermod Member submarine fan system, a well understood fan system from the Northern North Sea, and to simple synthetic models. Observations made from RGB imaging are compared to equivalent results from synthetic models created using well measurements and systematic variations in reservoir parameters. We show that thickness variations between events are the dominant factor controlling RGB colour response and that subtle lithological changes, presented as differences in acoustic impedance, are a second order effect. Furthermore, when the source frequency and decomposition bands of a synthetic wedge model are matched to a real dataset, we can relate colour values directly to thicknesses. In doing so we extend the classical tuning wedge for use as a calibration tool for frequency decomposition colour blends.