Oil and Gas Basin
An oil and gas basin serves as the very beginning of the many petroleum products we use today, including gas in our cars. Basin is actually a geographical term, but it’s also a common term in the oil and gas industry.
Did you know that there are 600 sedimentary basins in the world? But, interestingly, only a fraction of them account for the most oil and gas production. That’s because oil and gas reserves are distributed quite unevenly around the world. So it would come as no surprise that the Middle East has the most reserves, and of course, the most basins.
What is a Basin?
In the oil and gas industry, a basin is a depression in the Earth’s crust that contains sediment. These basins have formed over thousands of years due to tectonic plate movements and accumulated sediment over time. Erosion can also contribute to basin formation below ground.
Sediment is the remains of plants and animals (microorganisms mainly) that have been pushed into the Earth’s crust and covered by soil and silt. After significantly long periods of burial, this sediment can develop into hydrocarbons. Therefore, the basins contain reserves of oil or gas.
However, not all basins have ample minerals, but most do contain shale to some extent.
Basins typically have a round bowl-like shape or elongated troughs.
These basins are also called sedimentary basins in the oil and gas industry.
Types of Basins
There are essentially three types of basins from a geographical point:
River Drainage Basin
A river drainage basin is an area where water through precipitation goes into the river or its tributaries. There’s continuous input and output of water in this drainage basin. In simpler words, this basin takes surface water and groundwater and drains it into the nearby water bodies.
River drainage basins may be connected to other basins at lower elevations.
Structural basins are formed on land, typically in dry regions. These basins form as a result of erosion on the surface or earthquakes. These are the basins where hydrocarbons form and may be extracted from. Most oil and gas basins around the world are structural basins.
Ocean basins are admittedly the largest. Basically, whole oceans are covered with basins, with the edges of the contents, called continental shelves, forming the sides of different ocean basins. With hundreds to thousands of meters of depth, the ocean basins are also constantly changing because of tectonic activity.
Ocean basins can also have oil and gas formations below the sea bed.
Basins and Reserves
There are many sedimentary basins around the world, but not all are the same. While the basins with proven oil and natural gas reserves number in the hundreds, not all are actively producing.
There are a number of factors that affect a basin’s ability to produce oil and natural gas fields. An oil or gas field is represented by one or more reservoirs where the minerals can be extracted from. Since basins can be very large, they can have multiple fields too.
Even if a region has the most number of sedimentary basins, and consequently, the most proven reserves of oil and gas, it does not mean that it will also be the largest producer. As a lot of factors impact the extraction and production of these minerals, proven reserves do not always mean higher production.
The best example is the Middle Eastern region which is home to almost half of the world’s proven oil and gas reserves. However, the countries in the region account for around 16 to 30 percent of the world’s oil production. Interestingly, the Middle East only has 2 percent of the world’s producing wells.
The reason why they have such large production, even with only 2 percent of the world’s producing wells, is that the region has some of the biggest basins and fields in the world. The Ghawar Oil Field is the largest in the world, located in the Saudi basin. It can produce a whopping 3.8 billion barrels per day.
Despite having the most proven reserves and some of the biggest oil fields, it only accounts for less than a third of the oil used in the world. This is because the production is not as high as it potentially can be for a variety of reasons. Plus, many countries are investing in exploration and production to find more reserves.
The US is the best example of that which has made a breakthrough with its shale oil production.
There’s a new term related to oil and gas basins now, the Super Basin.
Bob Fryklund and Pete Stark from IHS Markit came up with the term, which is defined as a producing basin that produces at least 5 billion barrels per day and has the same or more volume of reserves left. The definition also says that it has two or more petroleum systems, stacked reservoirs, paired with extraction and production infrastructure, and access to the oil market.
By this definition, there are various conditions that an oil and gas basin must meet to qualify as a super basin.
The Permian Basin in West Texas and New Mexico can be considered a Super basin because of its growing production, remaining proven reserves, and geological conditions like stacked reservoirs. Even though production declined after its peak in the 70s, it has started ramping up once again. It’s comparable with the Ghawar oil field in Saudi Arabia.
Oil and gas basins typically are surface or ocean basins with sediment containing hydrocarbons in them. There are hundreds of basins on land with crude oil, shale oil, and natural gas, some of which are truly gigantic and supply a significant amount of oil and gas for the world.
Basins are basically where geography, geology, and petroleum engineering merge, as all these fields involve the study of basins containing minerals. Normally, we don’t hear about basins as much as we do about individual oil fields because basins are typically quite large and may have several oil fields.