A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Bastia, R.
- Depositional Architecture of Mio-Pliocene Sequences in Offshore Bengal Basin
Authors
1 Reliance Industries Ltd , Mumbai, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 67, No Spl Iss 5 (2006), Pagination: 575-583Abstract
Bengal Basin located along the northeast coast of India has a thick pile of MIO-Pliocene sediments fed by a number of large rivers like Ganga, Brahmaputra, Mahanadi and smaller rivers like Subarnarekha, Baitaram and Brahmani. The basin covers an area of 40,000 sq km in the Bay of Bengal. The sediments in the present day shelf area exhibit a complex deposition history with unique juxtaposition of shallow and deep water sediments in the form of deltas, distributary channels, Pro-Delta sediments and incised canyons, filled up with channel-levee complex deposits.A detailed study was carried out on the morphology and architecture of the different depositional elements and units utilizing different vintages of 2D/3D seismic and data from drilled wells Geo-Body mapping and attribute studies reveal finer details of the complex system Special seismic attributes such as spectrally decomposed amplitude, waveform classifier and 'sweetness' (amplitude by square ischolar_main of frequency) were quiet helpful in understanding the morphological details of the system. The following depositional elements have been brought out
•Delta-Distributary channel complex associated with incised valley and tidal inlets.
•Shelfal Canyon cut and fill sequences.
o Simple canyon fills Simple "V" shaped cuts with fills in the form of low to moderate sinuous.
channels.
o Complex Canyon cut and fills Numerous, repeated canyon cuts caused by Mass-Wasting with intervening fills in the form of deep water to Sub-Aerial channels and deltaic progradational deposits.
•Deep-Water Channel Complex Fed by large canyon up-dip. These depositional elements do not form part of the canyon fill, but occur down-dip.
The sand and si1t lithological distribution in the above depositional complexes form the predominant hydrocarbon reservoir units. The numerous reservoir bodies within the above units of varying lateral and vertical extents, are expected to hold the future exploration potential in this frontier basin.
Keywords
Morphology, Architecture, Bengal Basin.
- Depositional Model and Reservoir Architecture of Tertiary Deep Water Sedimentation, Krishna-Godavari Offshore Basin, India
Authors
1 Reliance Industries Ltd, 'H' Block, DAKC, Thane Belapui Road, Navi Mumbai - 400 709, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 64, No 1 (2004), Pagination: 11-20Abstract
The Krishna-Godavari basin is located along the cast coast of India bordering the state of Andhra Pradesh and covers an area of 100,000 sq km both on-land and offshore. The basin evolved through Crustal rifting and subsequent drifting during the Mesozoic and Cenozoic. The basin comprises a vast range of depositional settings such as coastal plains, deltas, shelf slope apions and deep-sea fans.
Our study deals with the Tertiary deep-water sedimentation of the Krishna-Godavari basin. An innovative approach has been adopted for the first time in India to understand in detail the architecture of the potentially reservoir lithology pione geo-bodies (depositional elements) and play types in the basin, and the workflow included 3D seismic data acquisition, processing, and interpretation in an interactive workstation environment, integrated subsequently with wireline logs, coring and formation evaluation by utilizing the state-of the art techniques. By combining the structural stratigraphic and sedimentological features of the basin, a generic depositional model has been constructed for the formation of various geo-bodies in the Tertiary deep water intervals of the basin. This model envisions a point source feeding a canyon that leads down dip into several sinuous leveed channels. Each of these sinuous channels in turn branches into distributaries that terminate in lobes.
By using the methodology outlined here, one of the largest gas reserves of the world in recent years has been discovered in a multi stoned channel-levee facies in the basin. Based on the Identified play types thus far, it is believed that a huge potential future treasure of hydrocarbons is in store in the Krishna-Godavari basin to place India firmly on the deep-water hydrocarbon map of the world.