Petroleum and Middle Indus Basin Essay Example

Oil and Middle Indus Basin Essay Example Oil and Middle Indus Basin Essay Oil and Middle Indus Basin Essay Kohat-Potwar Oil and Gas Exploration and Production The main oil all around bored in present-day Pakistan was at Kundal on the Potwar Plateau in 1866. The primary business oil revelation was made in the Greater Indus Basin in 1914 when the Attock Oil Company finished a 214 ft well on a push blamed anticline close Khaur on the Potwar Plateau (Khan and others, 1986). Early accomplishment in the Kohat-Potwar geologic region served to concentrate a great part of the early investigation movement around there. The Sui field in the Sulaiman-Kirthar Foreland geologic region was the principal revelation outside of the Kohat-Potwar geologic area and is the biggest gas disclosure in Pakistan, with in excess of 5 trillion cubic feet (TCF) of gas holds. Found in 1952, the Sui field is a vault molded reef structure with an anticlinal surface articulation. The biggest stores were found in the 625 m thick Eocene Sui Formation Sui Main Limestone Member. The Sui Upper Limestone Member and upper Eocene Habib Rahi Limestone were additionally beneficial. In 1999, Upper Cretaceous Pab Sandstone Formation gas creation started at Sui field. Albeit exploratory wells had been recently bored in the Middle and Lower Indus Basins, the revelation of the Sui field quickened investigation endeavors during the 1950s. More revelations followed around there with the Zin gas field in 1954, the Uch gas field in 1955, and the Mari gas field in 1957. Investigation action expanded again during the 1980s, when distinguishing proof of a tilted deficiency hinder in the Lower Indus Basin prompted the revelation of a progression of oil fields. Despite the fact that there have been huge oil disclosures in the Lower Indus Basin, it stays a gas-inclined area. Gas revelations that are ascribed to the Sembar-Goru/Ghazij TPS have been made in Eocene, Paleocene, and Lower Cretaceous shakes on the Mari-Kandhot High in the Rajasthan Province of India. The Cambrian oil revelations in Rajasthan, notwithstanding, are past the degree of Sembar statement and are either sourced by updip hydrocarbon movement from the Sembar or almost certain by proximal more seasoned Mesozoic and early Paleozoic rocks. Sembar-Goru/Ghazij Composite Total Petroleum System The Sembar-Goru/Ghazij Composite Total Petroleum System (TPS) as characterized for this evaluation, is a north-south stretched zone reaching out from the Potwar-Kohat geologic region in the north to the 2,000 m bathymetric form in the Arabian Sea . The west limit agrees with the hub belt and western edge of the Indian plate and the eastern limit reaches out into India on the Indian Shield . Geochemical examinations of potential source shakes and delivered oil and gas have shown that the Lower Cretaceous Sembar Formation is the most probable wellspring of oil and gas for a large portion of the creating fields in the Indus Basin. Source Rocks While the Sembar has been distinguished as the essential source rock for a great part of the Greater Indus Basin, there are other known and potential source rocks. Rock units containing known or potential source rocks incorporate the Salt Range Formation Eocambrian shales, Permian Dandot and Tredian Formations, Triassic Wulgai Formation, Jurassic Datta Formation, Paleocene Patala Formation, Eocene Ghazij Formation, and lower Miocene shales. Of all the conceivable source shakes in the Indus Basin, be that as it may, the Sembar is the most probable hotspot for the biggest bit of the delivered oil and gas in the Indus foreland. In the Kohat-Potwar geologic region the Paleocene Patala Shale is the essential source rock for most, if not the entirety of the area. In the seaward territories of the Indus geologic territory, Miocene rocks are proposed to be acceptable hydrocarbon sources, with the Sembar contributing in the rack zone. The Lower Cretaceous Sembar Formation comprises primarily of shale with subordinate measures of siltstone and sandstone. The Sembar was kept over a large portion of the Greater Indus Basin in marine situations and ranges in thickness from 0 to in excess of 260 m (Iqbal and Shah, 1980). Rock-eval pyrolysis examinations of 10 examples from the Jandran-1 well in the Sulaiman Range of the foldbelt, show anâ in all probability end up being gas inclined. verage all out natural carbon content (TOC) of 1. 10 percent. The TOC esteems from the Sembar in two Badin territory wells in the foreland part of the Lower Indus Basin have TOC’s running from 0. 5 to 3. 5 percent and averaging around 1. 4 percent. A cross-plot of pyrolysis information on an altered van-Kreveln outline study shows that the natural issue in the S embar is primarily type-III kerogen, equipped for creating gas; be that as it may, extra restrictive information demonstrate the nearness of type-II kerogen just as type-III kerogen. As for the oil window (0. 6 1. 3 percent vitrinite reflectance), the Sembar ranges from thermally juvenile to over develop . The Sembar is all the more thermally develop in the western, all the more profoundly covered piece of the rack and gets shallower and less develop toward the eastern edge of the Indus Basinâ Conclusive geochemical information supporting a Sembar hotspot for the majority of the created oil and gas in the Indus Basin are missing; be that as it may, restricted accessible geochemical and warm information favor a Sembar source. Until this point in time, the main oil-beneficial districts in the Greater Indus Basin are the Potwar Plateau in the north and the Badin region in the Lower Indus Basin. Cross-plots of the carbon isotope proportions and the isoprenoid proportions of delivered oils in these two districts are unmistakably unique , demonstrating two diverse source rocks. Gas content changes all through the bowl with CO2 extending from lt; 1 percent to gt;70 percent, nitrogen lt; 1 percent to gt; 80 percent, and H2S lt; 0. percent to gt; 13 percent (IHS Energy Group, 2001). Supplies Productive stores in the Sembar-Goru/Ghazij Composite TPS incorporate the Cambrian Jodhpur Formation; Jurassic Chiltan, Samana Suk, and Shinawari Formations; Cretaceous Sembar, Goru, Lumshiwal, Moghal Kot, Parh, and Pab Formations; Paleocene Dungan Formation and Ranikot Group; and the Eocene Sui, Kirthar, Sakesar, Bandah, Khuiala, Nammal, and Ghazij Formations . The foremost stores are deltaic and shallow-marine sandstones in the lower some portion of the Goru in the Lower Indus Basin and the Lumshiwal Formation in the Middle Indus Basin and limestones in the Eocene Ghazij and identical stratigraphic units . Potential supplies are as thick as 400 m. Sandstone porosities are as high as 30 percent, however more generally run from around 12 to 16 percent; and limestone porosities run from 9 to 16 percent. The penetrability of these supplies ranges from 1 to gt; 2,000 milidarcies (md). Repository quality for the most part decreases a westbound way however store thickness increments. Due to the dynamic eastbound disintegration and truncation of Cretaceous shakes, the Cretaceous supplies all have erosional updip limits, while Tertiary stores expand more distant east overlying continuously more established rocks. Traps All creation in the Indus Basin is from auxiliary snares. No stratigraphic collections have been recognized, in spite of the fact that the monster Sui gas field is a vault molded reef structure (perhaps an algal hill) communicated on a superficial level as an anticline. The assortment of auxiliary snares incorporates anticlines, push blamed anticlines, and tilted deficiency squares. The anticlines and pushed anticlines happen in the foreland parts of the Greater Indus Basin as an outcome of pressure identified with crash of the Indian and Eurasian plates. The tilted shortcoming traps in the Lower Indus Basin are a result of augmentation identified with breaking and the development of horst and graben structures. The fleeting connections among trap development and hydrocarbon age, removal, relocation, and capture are variable all through the Greater Indus Basin. In the foreland divide, development of basic snares pre-date hydrocarbon age, particularly in the Lower Indus Basin. In the Middle and Upper Indus Basins, traps may likewise have framed preceding hydrocarbon age, despite the fact that the transient connections between trap arrangement and hydrocarbon age are not as unmistakable as in the Lower Indus Basin. The auxiliary twisting in the foldbelt locale is commonly contemporaneous with hydrocarbon age, recommending that a portion of the hydrocarbons created from the Sembar likely spilled to the surface before trap development. Internment history recreations dependent on information from the Sakhi-Sarwar no. 1 well , situated in the foreland part of the Middle Indus Basin, and the Shahdapur no. 1 well, situated in the foreland part of Lower Indus Basin, demonstrate that hydrocarbon age started 40 and 65 Ma, separately . The primary contrasts in the hydrocarbon age times between these wells are because of enormous contrasts in the warm slopes; the present-day warm inclination in the Sakhi-Sarwar well is 2. 6Â °C/km instead of 3. 3Â °C/km in the Shahdapur well. We decipher the crucial points in time for these wells at around 15 and 50 Ma, separately. In view of these recreations, trap arrangement may have postdated the beginning of hydrocarbon age in the foreland segment of the Indus Basin. Seals The known seals in the framework are made out of shales that are interbedded with and overlying the repositories. In delivering fields, slight shale beds of variable thickness are compelling seals. Extra seals that might be viable incorporate impermeable seals above truncation traps, flaws, and updip facies changes. Overburden Rock The stones overlying the Sembar are made out of sandstone, siltstone, shale, limestone, and aggregate. The most extreme thickness of these overlying rocks is evaluated to be as much as 8,500 m in the Sulaiman foredeep region . In the foredeep territories quickly contiguous the front of the foldbelt parts of the Indus Basin, the overburden thickness ranges from 2,500 m to 6,0