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.
Cambay Basin | NDR – National Data Repository 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. More than exploratory wells have been drilled in Geollgy Basin. Cambay Basin Basin Introduction: 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. Different Tectonic Zones with in the Basin The Cambay rift valley is bounded by well demarcated basin margin step faults. 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. 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.
Petroleum geology of the Cambay Basin, Gujarat., India in SearchWorks catalog
The Middle Eocene witnessed a regressive phase with oscillating conditions of deposition and development of deltaic sequences in the entire basin.
Reservoir Rock There are a number of the geoloyg within the trapwacke sequence of the Olpad Formation. The Bouguer anomaly map has helped in identification of the major structural highs and lows in the basin.
Based on the cross trends the basin has been divided into five tectonic blocks.
This site basib best viewed using current versions of Firefox v. This turned out to be a discovery well, which produced oil and gas.
These sediments are vasin by an assortment of illsorted, high energy trap derived materials. The associated unconformity also helped in the development of secondary porosity. Subsequently, there was a strong tectonic activity that resulted in the development of the Mehsana Horst and other structural highs associated with basement faults. The end of deposition of the Olpad Formation is marked by a prominent unconformity.
This shale sequence has been baein into Older and Younger Cambay Shale with an unconformity in between. A total of more than 30, LKM of conventional data has been acquired. The magnetic anomaly map also depicts the broad structural configuration czmbay the basin. 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.
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. The total volume of seismic reflection data acquired from the Baasin Basin is of the order of LKM 2D and sq. 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.
During Miocene The depocenters continued to subside resulting in the deposition of enormous thickness of Miocene sediments as the Babaguru, Kand and Jhagadia formations. From north to south, the blocks are:. During Pleistocene to Recent, the sedimentation was mainly of fluvial type represented cajbay characteristic deposits of coarse sands, gravel, clays and kankar followed by finer sands and clays, comprising Gujarat Alluvium.
Shales within the Miocene section in the Broach depression might have also acted as source rocks. Trap Rock The most significant factor that controlled the accumulation of hydrocarbons in czmbay Olpad Formation is the favorable lithological change csmbay structural support geopogy short distance migration.
Pliocene was a period of both low and high strands of the sea level, allowing the deposition of sand and shale.
Out of prospects drilled, 97 are oil and gas bearing. 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 cambya.
Oligocene — Lower Miocene marks another phase of tectonic activity with extensive deposition of coarser clastic sediments in the central and southern blocks. The lithological heterogeneity gave rise to permeability barriers, which facilitated entrapment egology hydrocarbons. In the north, the basin narrows, but tectonically continues beyond Sanchor to pass into the Barmer Basin of Rajasthan. Similarly, the Proto—Narmada river system was active in the south, supplying sediments from provenance, lying to the east.
The end of the Paleogene witnessed a major tectonic activity in the basin resulting in the development of a widespread unconformity.
The end of Cambay Shale deposition is again marked by the development of a widespread unconformity that is present throughout the basin.
Subsidence of the basin resulted in the accumulation of a thick sequence of euxinic black shales with subordinate coarser clastics.