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 primary 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 achievement in the Kohat-Potwar geologic region served to concentrate a significant part of the early investigation action here. The Sui field in the Sulaiman-Kirthar Foreland geologic region was the main disclosure outside of the Kohat-Potwar geologic area and is the biggest gas revelation in Pakistan, with in excess of 5 trillion cubic feet (TCF) of gas holds. Found in 1952, the Sui field is an arch 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 likewise profitable. In 1999, Upper Cretaceous Pab Sandstone Formation gas creation started at Sui field. Albeit exploratory wells had been recently penetrated 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 recognizable proof of a tilted issue hinder in the Lower Indus Basin prompted the revelation of a progression of oil fields. In spite of the fact that there have been noteworthy oil disclosures in the Lower Indus Basin, it stays a gas-inclined region. Gas disclosures that are credited 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 disclosures in Rajasthan, in any case, are past the degree of Sembar testimony and are either sourced by updip hydrocarbon relocation from the Sembar or almost certain by proximal more established 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 appraisal, is a north-south prolonged territory stretching out from the Potwar-Kohat geologic region in the north to the 2,000 m bathymetric shape in the Arabian Sea . The west limit concurs with the hub belt and western edge of the Indian plate and the eastern limit stretches out into India on the Indian Shield . Geochemical investigations 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 the majority of the creating fields in the Indus Basin. Source Rocks While the Sembar has been recognized as the essential source rock for a significant 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, in any case, the Sembar is the most probable hotspot for the biggest segment of the created 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 region. In the seaward regions of the Indus geologic territory, Miocene rocks are hypothesized to be acceptable hydrocarbon sources, with the Sembar contributing in the rack region. The Lower Cretaceous Sembar Formation comprises for the most part of shale with subordinate measures of siltstone and sandstone. The Sembar was stored over the vast majority 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 likelihood 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 zone wells in the foreland bit 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 a changed van-Kreveln chart study demonstrates that the natural iss ue in the Sembar is essentially type-III kerogen, equipped for creating gas; in any case, extra restrictive information show the nearness of type-II kerogen just as type-III kerogen. Regarding the oil window (0. 6 1. 3 percent vitrinite reflectance), the Sembar ranges from thermally youthful 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 greater part of the delivered oil and gas in the Indus Basin are missing; in any case, restricted accessible geochemical and warm information favor a Sembar source. Until this point, the main oil-beneficial locales in the Greater Indus Basin are the Potwar Plateau in the north and the Badin territory in the Lower Indus Basin. Cross-plots of the carbon isotope proportions and the isoprenoid proportions of delivered oils in these two locales are unmistakably unique , demonstrating two distinctive 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). Repositories Productive supplies 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 central supplies 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 ordinarily go from around 12 to 16 percent; and limestone porosities go from 9 to 16 percent. The penetrability of these repositories ranges from 1 to gt; 2,000 milidarcies (md). Repository quality for the most part reduces a westbound way yet store thickness increments. As a result of the dynamic eastbound disintegration and truncation of Cretaceous shakes, the Cretaceous stores all have erosional updip limits, though Tertiary repositories expand more remote east overlying dynamically more seasoned rocks. Traps All creation in the Indus Basin is from basic snares. No stratigraphic gatherings have been recognized, in spite of the fact that the monster Sui gas field is a vault molded reef structure (conceivably an algal hill) communicated on a superficial level as an anticline. The assortment of basic snares incorporates anticlines, push blamed anticlines, and tilted shortcoming squares. The anticlines and pushed anticlines happen in the foreland parts of the Greater Indus Basin as a result of pressure identified with impact of the Indian and Eurasian plates. The tilted issue traps in the Lower Indus Basin are a result of augmentation identified with breaking and the arrangement of horst and graben structures. The transient connections among trap development and hydrocarbon age, ejection, movement, and capture are variable all through the Greater Indus Basin. In the foreland partition, 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 shaped preceding hydrocarbon age, despite the fact that the fleeting connections between trap arrangement and hydrocarbon age are not as particular as in the Lower Indus Basin. The basic misshapening in the foldbelt district is commonly contemporaneous with hydrocarbon age, recommending that a portion of the hydrocarbons produced from the Sembar presumably spilled to the surface before trap development. Internment history reproductions 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, show that hydrocarbon age started 40 and 65 Ma, individually . The fundamental contrasts in the hydrocarbon age times between these wells are because of huge contrasts in the warm slopes; the present-day warm inclination in the Sakhi-Sarwar well is 2. 6Â °C/km rather than 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 reproductions, trap arrangement may have postdated the beginning of hydrocarbon age in the foreland part of the Indus Basin. Seals The known seals in the framework are made out of shales that are interbedded with and overlying the supplies. In creating fields, meager shale beds of variable thickness are compelling seals. Extra seals that might be compelling incorporate impermeable seals above truncation traps, deficiencies, and updip facies changes. Overburden Rock The stones overlying the Sembar are made out of sandstone, siltstone, shale, limestone, and combination. 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 zones promptly contiguous the front of the foldbelt parts of the Indus Basin, the overburden thickness ranges from 2,500 m to 6,0