Persian gulf basin

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Intro

The Persian Gulf Basin, also known as the Arabian Gulf Basin, is located between the Eurasian and the Arabian Tectonic plates. The basin boarders most of the gulf coast countries including, Saudi Arabia, Kuwait, Qatar, Iraq, Oman, The United Arab Emirates, Iran, and Bahrain. The Persian Gulf Basin exists within the Persian Sea, also known as the Persian Gulf. The Persian Gulf Basin is a foreland basin that was created by a collision between the Arabian and Eurasian tectonic plates.

Oil and Gas Proved Reserves in Iran

History of the Basin

The Persian Gulf Basin was formed during the most recent glaciation of the earth, otherwise known as the most recent ice age, which ended 12,000 years ago.[1] During the Glacial period, the Basin sat above the maximum height of the glaciation. It was very likely that this was a swampy-like region where a lot of organic activity could occur.

The Persian Gulf Basin is the remains of a once much larger basin of deposition aligned northwest to southeast that existed throughout much of geologic history. In this basin vast quantities of sediments accumulated as mostly limestone, together with evaporites and organic matter, which is mostly from the Jurassic period, ultimately produced the area’s extensive oil resources.[2] Most of these sediments were produced from the Tigris and Euphrates rivers, which run through much of Asia and though Iraq, and lastly into the Persian Gulf.

The sea has an area of about 93,000 square miles (241,000 square km). Its length is some 615 miles (990 km), and its width varies from a maximum of about 210 miles (340 km) to a minimum of 35 miles (55 km) in the Strait of Hormuz. The Basin accounts for a large amount of petroleum reserves in the world, holding nearly fifty-five percent of global oil reserves.

Primary Risks and Uncertainties

Military Location during Gulf War

In the Persian Gulf Basin more than 51% of recoverable liquid hydrocarbons are located in Cretaceous reservoir rocks whereas up to 50% of the gaseous hydrocarbons were discovered in Triassic rock. A large majority of the basin consists of carbonate rock with more than 80% of petroleum reserves being contained within said carbonate rocks, only 20% are confined to sandstones.[3] This is a fairly safe basin to drill into, as it is one of the largest basins in the entire world. Below is a map of proved drilling from Iran.

Due to the fact that much of the basin consists of conventional plays, this makes it a fairly source of long term drilling. This also means that much of the basin will be around for a long time, without the majority of its reserves being depleted.

The main risks that reside in this basin come from political risks in the region. The Persian Gulf Region has been under much conflict in the last thirty years, with several wars occurring in the region. One of the main reasons for this conflict is common in the region is due to the large amount of oil reserves. One example of the political risk and uncertainties is the gulf war, much conflict in the region surrounded the control of this particular basin.

Petroleum Geology

Trap

The Traps found in the Persian Gulf Basin are mainly structural traps. Most of the structural traps in the region are anticlinal traps and salt domes, which trap the oil and gas at the top of the dome. The Basin also contains many faults, which are another form of structural traps within the region.

Seal

The Seal in the Persian Gulf Basin is largely limestone from deposited sediments which were brought to the basin from the Tigris and Euphrates rivers. This limestone mostly has carbonate composition, and helps create a reservoir for the hydrocarbons to remain in place.

Source Rock

Source rock in the Persian Gulf Basin consist mainly of Proterozoic sediments, some 4 km thick, yield oil in eastern Arabia (Oman), which emanates from salt-related kerogenous source rocks. Most Paleozoic and Mesozoic reservors in this area contain Proterozoic oil which has migrated both laterally and upwards along fractures.[4]

Reservoir

The Persian Gulf Basin reservoir consists of mainly Jurassic period limestone. Roughly 80 percent of the reservoir is limestone, while the other 20 consists of shales and mudstones. Most of the carbonate limestone came from deposition into the Persian Gulf, which mainly was sourced from the Tigris and Euphrates rivers.[5]

Future/Current Assessment of the Persian Gulf Basin

Persian Gulf Basin Reserves

Currently, the Persian Gulf Basin has strong conventional reserves. As the reservoir continues to be depleted over the next century, likely methods that can be used to are hydraulic fracturing, or fracking. Once the conventional reserves get depleted, producers in the region will have to shift to unconventional reservoirs. These Unconventional reservoirs will likely be in the shales and mudstones below the current basin.

By using unconventional recovery methods this will allow for producers to increase the longevity of the current plays within the reservoir. Likely, this will be a reliable and heavily produced basin for a long time going forward.

Unconventional plays are still fairly new to the Persian Gulf Basin, so there is a lot of future potential for E&P going forward.

Engineering Aspects

This basin has huge potential, both onshore and offshore. The most promising plays in the basin are on the Saudi Arabian Side of the basin in the Ghawar Shale. The Iranian side of the basin has very promising cites for drilling as well. Historically the Persian Gulf Basin has been one of the most plentiful basins in terms of oil and gas potential; this means that there is currently few operations occurring where much recovery methods are required. The Persian Gulf Basin is one of the best performing basins in the world at producing oil and gas. Much of the crude produced in the Persian Gulf Basin comes from the Ghawar basin and produces mostly Arabian Light and Arabian Super Light crude[6].

References

  1. Persian Gulf. (n.d.). Retrieved May 11, 2021, from https://www.newworldencyclopedia.org/entry/Persian_Gulf#History
  2. Persian Gulf. (n.d.). Retrieved May 11, 2021, from https://www.britannica.com/place/Persian-Gulf
  3. Rabbani, A. R. (n.d.). Petroleum Geology and Geochemistry of the Persian Gulf. Retrieved May 11, 2021, from https://www.researchgate.net/publication/259527721_Petroleum_Geology_and_Geochemistry_of_the_Persian_Gulf
  4. Edgell, H. (2003, April 22). Proterozoic salt basins of the Persian Gulf area and their role in Hydrocarbon generation. Retrieved May 11, 2021, from https://www.sciencedirect.com/science/article/abs/pii/030192689190065I
  5. Masters thesis on Arabian Basin petroleum - SEPM Strata. (n.d.). Retrieved May 11, 2021, from http://www.sepmstrata.org/page.aspx?&pageid=135&4
  6. Oil production. (n.d.). Retrieved May 11, 2021, from https://www.aramco.com/en/creating-value/products/oil