Download/Embed scientific diagram | Geological map of Cambay Basin, western India. from publication: Early Eocene equatorial vegetation and depositional. In the southern Cambay Basin, it was sourced from a higher plant fraction deposited in marine or fluvial deltaic environment (Sivan et al., ). It is based on the Sub-surface study of on oil field in Cambay basin. After a brief description of the Cambay basin’s geology, the other aspects of exploration were .
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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. 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. Throughout the geological history, except during early syn— rift stagethe North Cambay Basin received major clastic inputs from north and northeast, fed by the Proto—Sabarmati and Proto—Mahi rivers.
The discovery of oil in Ankleshwar structure in gave boost to the exploration in the Cambay Basin. The end of deposition of the Olpad Formation is marked by a prominent unconformity.
Based on the cross trends the basin has been divided into five tectonic blocks. These sediments are characterised by an assortment of illsorted, high energy trap derived materials.
During Miocene The depocenters continued to subside resulting in the deposition of enormous thickness of Miocene sediments as goelogy Babaguru, Kand and Jhagadia formations. 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 important hydrocarbon source rock.
Cambay Basin | NDR – National Data Repository India
Gradually, the rift valley expanded with time. Basim lithological heterogeneity gave rise to permeability barriers, which facilitated entrapment of hydrocarbons. Similarly, the Proto—Narmada river system was active in the south, supplying sediments from provenance, lying to the east. 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.
Subsidence of the basin resulted in the accumulation of a thick sequence of euxinic black shales with subordinate coarser clastics. The total volume of seismic reflection data acquired from the Cambay Basin is of the order of LKM 2D and sq.
Different Tectonic Zones with in the Basin The Cambay rift valley is bounded by geolkgy demarcated basin margin basni faults.
The NW-SE Dharwarian tectonic trends got rejuvenated creating a narrow rift geoligy extending from the Arabian sea south of Hazira to beyond Tharad in the north. The Bouguer anomaly map has helped in identification of the major structural highs and lows in the basin.
Reservoir Rock There are a number of the reservoirs within the trapwacke sequence of the Olpad Formation.
The same is true for the Tarapur Shale. The magnetic anomaly map also depicts the broad structural configuration of the basin. This shale sequence has been divided into Older and Younger Cambay Shale with an unconformity in nasin. The end of the Paleogene witnessed a major tectonic activity in the basin resulting in the development of a widespread unconformity.
Cambay Basin Basin Introduction: From north to south, the blocks are:. More than exploratory wells have been drilled in Cambay Basin.
The end of Cambay Shale deposition is again marked by the development of a widespread unconformity that is present throughout the basin. Seismic and drilled well data indicate a thickness of about 8 km of Tertiary sediments resting over the Deccan volcanics.
This site is best viewed using current versions of Firefox v. There was a regional southward tilt of the entire rift basin during Late Eocene and it is marked by a regional marine transgression extending far to the north upto Sanchor basin.
In the north, the basin narrows, but tectonically continues beyond Sanchor to pass into the Barmer Basin of Rajasthan. Out of prospects drilled, 97 are oil and gas bearing.
Subsequently, there was a strong tectonic activity that resulted in the development of the Mehsana Horst and other structural highs geo,ogy with basement faults. 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.
Petroleum geology of the Cambay Basin, Gujarat., India in SearchWorks catalog
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.
At places a gradational contact with the overlying Cambay Shale has also been noticed. 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.
A total of more than 30, LKM of conventional data has been acquired. Shales within the Miocene section in the Broach depression might have also acted as source rocks.