A Revised Plate Model for the Myanmar and Andaman Sea Regions and its Effects on Petroleum Systems
Abstract
With the Myanmar and Andaman Sea regions opening up for hydrocarbon exploration, we have revised our existing plate models, crustal types classification and structural maps of the area. Using our updated plate model and crustal types classification, the tectonic evolution of the area can be better understood, which can help to pinpoint when and where accommodation space was available for sediment accumulation. Using the structural map, we can highlight areas for structural trap
development and predict the types of traps that could develop in certain areas. In order to high grade areas where good-quality source rocks, reservoirs or seals are likely to be present, we have integrated drainage analysis and provenance assessment with the revised plate model and crustal types classification. For our integrated tectonic model and structural mapping we primarily used potential field (gravity and magnetic) data. We used Landsat and SRTM data onshore and our in-house database which consists of a large number of third party information, including well, location line and map data. Our preferred plate model was derived from comparing and contrasting published (end member) regional models against all available control data in our Global Plate Model. Using the Global Plate Model allowed us to test regional models in a global context, checking the global effects of each individual regional model. Crustal types were primarily derived from crustal architecture grids; these grids included depth-to-basement and depth-to-Moho grids which were calculated from potential field data inversion and refined using third party control data. The main plate tectonic problems we addressed included: a) the Andaman Sea: where has ocean spreading occurring and where is the limit of transitional and attenuated continental crust?; b) the Sagaing
Fault
: quantifying the displacement at different geological times and pinpointing transtensional and transpressional segments; c) Bangladesh: how far north is the limit of subduction of oceanic and transitional crust beneath the Ganges-Brahmaputra Delta, and d) the Bengal Fan Basin: what is the fracture zone orientation beneath the thick sedimentary cover? Additionally, focussing on the evolution of the palaeo-Irrawaddy, we also attempted to assess whether clastic sediments were shed predominantly towards the Andaman Fore-arc and Martaban Basins or towards the Rakhine Basin during the Cenozoic.
AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016