The Cambay rift Basin, a rich Petroleum Province of India, is a narrow, .. Throughout the geological history, except during early syn– rift stage, the North. Petroleum Geology of the Cambay Basin, Gujarat., India. Front Cover. L. R. Chowdhary. Indian Petroleum Publishers, – Petroleum – pages. Petroleum geology of the Cambay Basin, Gujarat., India. Responsibility: L.R. Chowdhary. Imprint: Dehradun: Indian Petroleum Publishers, c Physical.
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Pliocene was a period of both low and high strands of the sea level, allowing the deposition of sand and shale.
Cambay Basin | NDR – National Data Repository India
The discovery of oil in Ankleshwar structure in gave boost to the exploration in the Cambay Basin. The end of this sequence is marked by a regressive phase leading to deposition of claystone, sandstone, and shale alternations and a limestone unit of the Dadhar Formation. Reservoir Rock There are a number of the reservoirs within the trapwacke sequence of the Olpad Formation.
These consist of sand size basalt fragments.
This site is best viewed using current versions of Firefox v. During Pleistocene to Recent, the sedimentation was mainly of fluvial type represented by characteristic deposits of coarse sands, gravel, clays and kankar followed by finer sands and clays, comprising Gujarat Alluvium.
Trap Rock The most significant factor that controlled the accumulation of hydrocarbons in the Geoloby Formation is the favorable lithological change with structural support and short distance migration. This shale sequence has been divided into Older and Younger Cambay Shale with an unconformity in between. During Early Eocenea conspicuous and widespread transgression resulted in the deposition of a thick, dark grey, fissile pyritiferous shale sequence, known as the Cambay Shale.
Different Tectonic Zones with in the Basin The Cambay rift valley is bounded cambag well demarcated basin margin step faults.
The same is true for the Tarapur Shale. Out of prospects drilled, 97 are oil and gas bearing. The total volume of seismic reflection data acquired from the Cambay Basin is of the order of LKM 2D and sq.
The end of deposition of the Olpad Formation is marked by a prominent unconformity. The lithological heterogeneity gave rise to permeability barriers, which facilitated entrapment of hydrocarbons.
Based on the cross trends the basin has been divided into five tectonic blocks. Geographic Location of the basin The Cambay rift Basin, a rich Petroleum Province of India, is a narrow, elongated rift graben, extending from Surat in the south to Sanchor in the north.
From north to south, the blocks are:. In the north, the basin narrows, but tectonically continues beyond Sanchor to pass into the Barmer Basin of Rajasthan. Cambay Basin Basin Introduction: Oligocene — Lower Miocene marks another phase of tectonic activity with extensive deposition of coarser clastic sediments in the central and southern blocks.
The formation of the Cambay Basin began following the extensive outpour of Deccan basalts Deccan Trap during late Cretaceous covering large tracts of western and central India. In the northern part of the Ahmedabad-Mehsana Nasin, coal, which is well geolog within the deltaic sequence in Kalol, Sobhasan and Mehsana fields, is also inferred to be an important hydrocarbon source rock.
The Bouguer anomaly map has helped in identification of the major structural highs and lows in the basin.
Similarly, the Proto—Narmada river system was active in the south, supplying sediments from provenance, lying to baein east. This turned out to be a discovery well, which produced oil and gas. Subsidence of the basin resulted in the accumulation of a thick sequence of euxinic black shales with subordinate coarser clastics.
The magnetic anomaly map also depicts the broad structural configuration of the basin. During Paleocenethe basin continued to remain as a shallow depression, receiving deposition of fanglomerate, trap conglomerate, trapwacke and claystone facies, especially, at the basin margin under a fluvio—swampy regime.
The associated unconformity also helped in cqmbay development of secondary porosity. Shales within the Miocene section in the Broach depression might have also acted as source rocks. These sediments are characterised by an assortment of illsorted, high energy trap derived materials.
At places a gradational contact with the overlying Cambay Shale has also been noticed. Throughout the geological history, except during early syn— rift stagegeeology North Cambay Basin received major clastic inputs from north and northeast, fed by the Proto—Sabarmati and Proto—Mahi rivers.