Fine-grained deep-water turbidite gas reservoirs in upper Bengal Fan

The Bengal Fan is a mud-rich, deep-water sediment system. A series of recently discovered biogenic gas reser-voirs in the northeastern Bay of Bengal are fine-grained. The Pliocene gas discovered in the study area accu-mulated in the levee element of a deep-water channel complex identified by high-resolution three-dimensional (3D) seismic interpretation integrated with well logs and sidewall cores (SWC). The thickness and porosity of the levee gas reservoir are of good quality, but the permeability is relatively low owing to the high mud content. The discovery of the levee sandstone indicates various reservoirs in this mud-rich sediment system. Moreover, gas discovery implies that the gravity-flow sediment systems link the source rock in the study area. Gas reservoirs were discovered in Pliocene gravity-flow sediment systems, where the palaeo-climate experienced significant changes with a dramatic increase in total organic carbon (TOC) from the Miocene to the Pliocene. TOC-rich pelagic mudstones and deep-water gravity sediments act as source rocks for petroleum systems. Therefore, gravity-flow sediment systems have developed self-accumulating petroleum plays that exhibit enormous po-tential for exploration. Given the structural framework in the northeastern part of the Bay of Bengal, strati-graphic or structure-stratigraphic traps could have developed in the Pliocene deep-water sediment systems in the Bengal Fan.

Automated summary

The Bengal Fan is a deep-water sediment system with recently discovered biogenic gas reservoirs. The levee gas reservoir in this system has good thickness and porosity but low permeability due to high mud content. The gravity-flow sediment systems are linked to the source rock in this area and show enormous potential for petroleum exploration.