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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During Miocene The depocenters continued to subside resulting in the deposition of enormous thickness of Miocene sediments as the Babaguru, Kand and Jhagadia formations. Different Tectonic Zones with in the Basin The Cambay rift valley is bounded by well demarcated basin margin step faults.
Petroleum geology of the Cambay Basin, Gujarat., India in SearchWorks catalog
This site is best viewed using current versions of Firefox v. 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 of hydrocarbons.
Subsidence of the basin resulted cabay the accumulation of a thick sequence of euxinic black shales with subordinate coarser clastics. The associated unconformity also helped in the development of secondary porosity. Gradually, the rift valley expanded with time. In the northern part of the Geplogy 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.
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 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.
Cambay Basin | NDR – National Data Repository India
cwmbay 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 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.
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. Similarly, the Proto—Narmada river system was active in the basij, supplying sediments from provenance, lying to the east.
The Middle Eocene witnessed a regressive phase with oscillating conditions of deposition and development of deltaic sequences in the entire basin. Besides this, localized sandstone reservoirs within the Cambay Shale as in the Unawa, Linch, Mandhali, Mehsana, Sobhasan, fields, etc are also present.
A total of more than 30, LKM of conventional data baisn been acquired. This turned out to be caambay discovery well, which produced oil and gas.
Seismic and drilled well data indicate a thickness of about 8 km of Tertiary sediments resting over the Deccan volcanics. At places a gradational contact with the overlying Cambay Shale has also cambayy noticed. 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.
The magnetic anomaly map also depicts the broad structural configuration of the basin. Geographic Location of cmabay 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. 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 Bouguer anomaly basiin has helped in identification of the major structural highs and lows in the basin. These consist of sand size basalt fragments. In the north, the basin narrows, but tectonically continues beyond Sanchor to pass into the Barmer Basin of Rajasthan. From north to south, the blocks are:. The same is true for the Tarapur Shale.
Based on the cross trends the basin has been divided into five tectonic blocks. Reservoir Rock There are a number of the reservoirs within the trapwacke sequence of the Olpad Formation. Shales within the Miocene section in the Broach depression might have also acted as source rocks.
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.
This shale sequence has been divided into Older and Younger Cambay Shale with an unconformity in between. Subsequently, there was a strong tectonic activity that resulted in the development of the Mehsana Horst and other structural highs associated with basement faults. Out of prospects drilled, 97 are oil and gas bearing.