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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Oligocene — Lower Miocene marks another phase of tectonic activity with extensive deposition of coarser clastic sediments in the central and southern blocks. Gradually, the rift valley expanded with time. The total volume of seismic reflection data acquired from the Cambay Basin is of the order of LKM 2D and sq. These sediments are characterised by an assortment of illsorted, high energy trap derived materials.
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 geoogy, trap conglomerate, trapwacke and claystone facies, especially, at the basin margin under a fluvio—swampy regime.
At geologyy a gradational contact with the overlying Cambay Shale has also been noticed. 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.
The end of the Paleogene witnessed a major tectonic activity in the basin resulting in the development of a widespread unconformity. The Early Tertiary sediments ranging in age from Paleocene to Early Eocene represent syn-rift stage of deposition that was controlled by faults and basement highs in an expanding rift system.
In the north, the basin narrows, but tectonically continues beyond Sanchor to pass into the Barmer Basin of Rajasthan. Shales within the Miocene section in the Broach depression might have also acted as source rocks. The end of Cambay Shale deposition is again marked by the development of a widespread unconformity that is present throughout the basin. Throughout the geological history, except during early syn— rift stagethe North Cambay Basin received major clastic inputs from north baein northeast, fed by the Proto—Sabarmati and Proto—Mahi rivers.
During Early Eocenea conspicuous and widespread transgression resulted in the deposition of a thick, dark grey, fissile pyritiferous bazin sequence, known as the Cambay Shale.
The end of deposition of the Olpad Formation is marked by camvay prominent unconformity. Similarly, the Proto—Narmada river system was active in the south, supplying sediments from provenance, lying to the east.
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. During Pleistocene to Recent, the sedimentation was mainly of od type represented by characteristic deposits of coarse sands, gravel, clays and kankar followed by finer sands and clays, comprising Gujarat Alluvium.
This turned out to be a discovery well, which produced oil and gas. This site is best viewed using current versions of Firefox v. The end of this sequence is marked cammbay a regressive phase leading to deposition of claystone, sandstone, and shale alternations and a limestone unit of the Dadhar Formation.
More than exploratory wells have been drilled in Cambah Basin. Seismic and drilled well data indicate a thickness of about 8 km of Tertiary sediments resting over the Deccan volcanics. These consist of sand size basalt fragments.
Cambay Basin | NDR – National Data Repository India
Trap Rock The most significant factor that controlled the accumulation of hydrocarbons in the Olpad Formation is the favorable lithological change with structural support and short distance migration. In the following period, relative subsidence of the basin continued leading to the accumulation of the Younger Cambay Shale.
Subsequently, there was a strong tectonic activity that resulted in the development of the Mehsana Horst and other structural highs associated with basement faults.
In the northern part of the Ahmedabad-Mehsana Block, coal, which is well developed within the deltaic sequence in Kalol, Sobhasan and Mehsana fields, is also inferred to be an geplogy hydrocarbon source rock.
Different Tectonic Zones with in the Basin The Cambay rift valley is bounded by well demarcated basin margin camnay faults. The NW-SE Dharwarian tectonic trends got rejuvenated creating a narrow rift graben extending from the Arabian sea south of Hazira to beyond Tharad in the north.
The lithological heterogeneity gave rise to permeability barriers, which facilitated entrapment of hydrocarbons.
This shale sequence has been divided into Older and Younger Cambay Shale with an unconformity in between. The Bouguer anomaly map has helped in identification of the major structural highs and lows in the basin. Cambay Basin Basin Introduction: Based on the cross trends the basin has been divided into five tectonic blocks. Pliocene was a period of both low and high strands of the sea level, allowing the deposition of sand and shale.
The discovery of oil in Ov structure in gave boost to the exploration in the Cambay Basin.