Understanding the distribution and geometry of reservoir geobodies is crucial for net-to-gross estimates and to model subsurface flow. This article focuses on the process of dolomitization and resulting geometry of diagenetic geobodies in an outcrop of Jurassic host rocks from northern Oman. Field and petrographic data show that a first phase of stratabound dolomite is crosscut by a second phase of fault-related dolomite. The stratabound dolomite geobodies are laterally continuous for at least several hundreds of meters (
1000 ft) and probably regionally and are one-half meter (1.6 ft) thick. Based on petrography and geochemistry, a process of seepage reflux of mesosaline or hypersaline fluids during the early stages of burial diagenesis is proposed for the formation of the stratabound dolomite. In contrast, the fault-related dolomite geobodies are trending along a fault that can be followed for at least 100 m (328 ft) and vary in width from a few tens of centimeters to as much as 10 m (
1–33 ft). Petrography, geochemistry, and high homogenization temperature of fluid inclusions all point to the formation of the dolomite along a normal fault under deep burial conditions during the Middle to Late Cretaceous. The high 87
Sr ratio in the dolomite and the high salinity measured in fluid inclusions indicate that the dolomitizing fluids are deep basinal brines that interacted with crystalline basement. The dolomitization styles have an impact on the dimension, texture, and geochemistry of the different dolomite geobodies, and a modified classification scheme (compared to the one from Jung and Aigner, 2012) is proposed to incorporate diagenetic geobodies in future reservoir modeling.
Added on 30 June, 2013
Discoveries were comparatively sparse, but they persisted steadily throughout the year. Here are some of the more significant discoveries of the past year.
Added on 01 January, 2014
Rocky road to success: AAPG member Simon Donato found adventure and much more – when he accepted the personal challenge of finding archaeological sites in the rugged and dangerous mountains overlooking the Strait of Hormuz.
Added on 01 February, 2012
Distinguished Lecturer Steve Dorobek’s Asia Pacific Region tour, originally slated for March, has been delayed until May – but the AAPG DL program will remain active in March with four speakers ready to tour.
Added on 01 March, 2011
Heavy oil in the Middle East – an overlooked potential?
Added on 01 May, 2010
Added on 01 January, 2000
Improved imaging technology has helped explorationists in the Sultanate of Oman reawaken a sleeping giant.
Added on 01 September, 2014
An added dimension: 3-D seismic data is an essential ingredient in operators’ efforts to understand the risks and nuances of shale plays.
Added on 01 March, 2012
Tough terrain, challenging locales, political upheavals: Welcome to the world of international seismic work, where the hardest part of the job might be just getting to the job.
Added on 01 March, 2008
Explorer Foundation Update
It has a new name, a new energy and a new lineup of experts, all primed to spread geoscience knowledge around the world. “It” is AAPG’s newly named Global Distinguished Lecture Program – emphasis on the “global” – which dates back to 1941 but continues to be the Association’s flagship initiative for offering the latest in geologic science to AAPG affiliated geological societies and universities.
Added on 01 October, 2014