Bulletin Article

7969
 

Diagenesis significantly impacts mudstone lithofacies. Processes operating to control diagenetic pathways in mudstones are poorly known compared to analogous processes occurring in other sedimentary rocks. Selected organic-carbon-rich mudstones, from the Kimmeridge Clay and Monterey Formations, have been investigated to determine how varying starting compositions influence diagenesis.

7966
 

The presence of hydrocarbon-bearing sandstones within the Eocene of the Forties area was first documented in 1985, when a Forties field (Paleocene) development well discovered the Brimmond field. Further hydrocarbons in the Eocene were discovered in the adjacent Maule field in 2009. Reservoir geometry derived from three-dimensional seismic data has provided evidence for both a depositional and a sand injectite origin for the Eocene sandstones. The Brimmond field is located in a deep-water channel complex that extends to the southeast, whereas the Maule field sandstones have the geometry of an injection sheet on the updip margin of the Brimmond channel system with a cone-shape feature emanating from the top of the Forties Sandstone Member (Paleocene). The geometry of the Eocene sandstones in the Maule field indicates that they are intrusive and originated by the fluidization and injection of sand during burial. From seismic and borehole data, it is unclear whether the sand that was injected to form the Maule reservoir was derived from depositional Eocene sandstones or from the underlying Forties Sandstone Member. These two alternatives are tested by comparing the heavy mineral and garnet geochemical characteristics of the injectite sandstones in the Maule field with the depositional sandstones of the Brimmond field and the Forties sandstones of the Forties field.

The study revealed significant differences between the sandstones in the Forties field and those of the Maule and Brimmond fields), both in terms of heavy mineral and garnet geochemical data. The Brimmond-Maule and Forties sandstones therefore have different provenances and are genetically unrelated, indicating that the sandstones in the Maule field did not originate by the fluidization of Forties sandstones. By contrast, the provenance characteristics of the depositional Brimmond sandstones are closely comparable with sandstone intrusions in the Maule field. We conclude that the injectites in the Maule field formed by the fluidization of depositional Brimmond sandstones but do not exclude the important function of water from the huge underlying Forties Sandstone Member aquifer as the agent for developing the fluid supply and elevating pore pressure to fluidize and inject the Eocene sand. The study has demonstrated that heavy mineral provenance studies are an effective method of tracing the origin of injected sandstones, which are increasingly being recognized as an important hydrocarbon play.

7965
 

Interpretation of seismic data from the Sorvestsnaget Basin, southwest Barents Sea, demonstrates gradual middle Eocene basin infilling (from the north) generated by southward-prograding shelf-margin clinoforms. The basin experienced continued accommodation development during the middle Eocene because of differential subsidence caused by the onset of early Eocene sea-floor spreading in the Norwegian-Greenland Sea, faulting, salt movement, and different tectonic activity between the Sorvestsnaget Basin and Veslemoy high. During this time, the margin shows transformation from an initially high-relief margin to a progradation in the final stage. The early stage of progradation is characterized by the establishment of generally oblique clinoform shifts creating a flat shelf-edge trajectory that implies a gentle falling or stable relative sea level and low accommodation-to-sediment supply ratio (lt1) in the topsets. During the early stage of basin development, the high-relief margin, narrow shelf, stable or falling relative sea level, seismicity, and presumably high sedimentation rate caused accumulation of thick and areally extensive deep-water fans. Seismic-scale sandstone injections deform the fans.

A fully prograding margin developed when the shelf-to-basin profile lowered, apparently because of increased subsidence of the northern part. This stage of the basin development is generally characterized by the presence of sigmoid clinoform shifts creating an ascending shelf-edge trajectory that is implying steady or rising relative sea level with an accommodation-to-sediment supply ratio of greater than 1, implying sand accumulation on the shelf. This study suggests that some volume of sand was transported into the deep water during relative sea level rise considering the narrow shelf and inferred high rates of sediment supply.

Explorer Article

8582
 

A three-day international conference honoring the life and work of the late AAPG Honorary member David Roberts, entitled “Basin Dynamics and Petroleum Systems: Geophysics, Structure, Stratigraphy, Sedimentology and Geochemistry.” will be held April 14-16 at Royal Holloway University, London, England.

8049
 

Online registration is open for this year’s AAPG Annual Convention and Exhibition, which will be held April 6-9 at the George R. Brown Convention Center in Houston – and reduced registration fees are still available for those who act fast.

Explorer Division Column EMD

3800
 

Every six months, chairs of the Energy Minerals Division committees convene and report on developments in the areas they cover. In this column, we highlight important observations from these recent reports.

Explorer Emphasis

8067
 

Imagine the insight to be gained from showing every aspect of an already drilled prospect, whether good or bad, to an audience of your peers for scrutiny. We’re talking peers from a company other than your own. There’s an industry forum that exists for this purpose.

8050
 

Seismic Outlook: After several years of plenty, 2014 is expected to be a comparatively lean year for the seismic industry, a few localized hot-spots around the world notwithstanding.

3794
 

Icebreaking vessels are the key to navigating the Arctic, and so are in high demand as oil producers set their sights on the vast oil reserves at the top of the world.

Explorer Historical Highlight

8590
 

Great Britain in the late 18th and early 19th centuries was undergoing great change. The Industrial Revolution was in full flood and there was an insatiable desire for coal to turn the wheels of industry.

Field Seminar

Naples Italy 20 September, 2014 26 September, 2014 36
 
Naples, Italy
20-26 September 2014

The main part of the field seminar will focus on the description of the fractured carbonates and the extrapolation from the outcrop observations to the subsurface for building geologically plausible reservoir models.

Barcelona Spain 22 September, 2014 26 September, 2014 153
 
Barcelona, Spain
22-26 September 2014

Participants will examine illustrative outcrops of thrusts, fault-related folds, stratal architectures and facies of depositional systems affected by growing structures, which are good analogues for hydrocarbon reservoirs. Objectives include interpreting complex thrust structures, identifying and understanding strain and fracture systems in fold-thrust belts, and analyzing patterns of growth strata in areas with synsedimentary folding.

Las Negras Spain 01 June, 2014 06 June, 2014 31
 
Las Negras, Spain
1-6 June 2014

The field seminar develops and evaluates the sequence stratigraphic framework and controls on location and reservoir character of Upper Miocene-Pliocene carbonate sequences from a variety of carbonate systems within the context of the regional paleogeography.

Workshop

Istanbul Turkey 09 June, 2014 11 June, 2014 8536
 
Istanbul, Turkey
9-11 June 2014

Unlock billions of $ in value by enabling insights through better accessibility, quality and use of data.

Coming Soon

Check back often. "Find an Expert" feature is coming online soon!

Andrea Moscariello Andrea Moscariello Advisory Counselor (2012-2015) University of Geneva +41.22.379.6610
Keith Dennis Gerdes Keith Dennis Gerdes President (2013-2015) Shell International E & P +31.62.123.6482
Jonathan Craig Jonathan Craig President Elect (2013-2015) ENI Exploration & Production Divison 39 02 5206 3596
Vlastimila Dvorakova Vlastimila Dvorakova Past President (2013-2015) Czech Geological Survey +42.05.4342.9253
Helen Cromie Helen Cromie Secretary (2011-2014) Maersk Oil +4540224142
Knut Henrik Jakobsson Knut Henrik Jakobsson Treasurer (2009-2016) The Norwegian Petroleum Directorate +47.94521894

The House of Delegates of the AAPG is made up of delegates from affiliated societies and international regions throughout the world. They are selected by popular vote from within their respective areas and serve a three year term.

Who Is My Delegate?