I study engineering geology and often work on geological projects for the Changqing Oilfield. I was curious about the term “ultra-low permeability oilfield” often mentioned on the commissioning orders, so I did some research. The concept isn’t too broad, and I’ll try to answer it.

Petroleum actually exists within rocks! Essentially like this

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There is still no consensus on how petroleum is formed, as it cannot be reproduced. In other words, there is no way to generate petroleum through experiments, so a definitive conclusion cannot be reached.

In general, there are two main hypotheses

First of all, petroleum is primarily composed of carbon-hydrogen organic compounds. This is a relatively mainstream viewpoint, and the comprehensive explanation of whether petroleum is formed due to organic or inorganic reasons is challenging. The formation process of petroleum is even more controversial.

Back when humans had not yet begun large-scale petroleum extraction, scientists speculated that petroleum was formed from the remnants of plants. Later, the Russian chemist Mendeleev proposed the carbide theory, which roughly suggests that petroleum originates from deep within the Earth’s carbide iron. It is believed that under the influence of geothermal heat and water, carbon-hydrogen compounds were formed, and due to their lighter nature, they rose to form petroleum. However, this theory is not very reliable because the carbide iron mentioned in Mendeleev’s hypothesis does not exist in large quantities.

Subsequently, discussions about petroleum shifted to the era of organic substances. Some believed that petroleum was formed from the deposition and burial of ancient marine organisms, primarily plants. The current mainstream hypothesis is based on the development of petroleum through the deposition of marine biological remains.

The organic origin theory suggests that in the early stages of life evolution, a large number of marine plant or animal remains accumulated on the seafloor. These remains were buried by sediment before they could be fully decomposed by microorganisms and subsequently sank under the influence of gravity. These organic materials then underwent a series of chemical changes under conditions such as high temperature and pressure, losing oxygen atoms to form simple carbon-hydrogen compounds. Different conditions give rise to different substances, with petroleum being just one of them. Similar substances include natural gas and coal, all of which result from the deposition of these organic materials.

The current debate also revolves around whether petroleum is renewable. According to the mainstream organic origin theory, petroleum regeneration is slow and challenging, and at our current rate of extraction, it may deplete in the short term. In contrast, the inorganic origin theory suggests that petroleum can regenerate rapidly, and there have been instances of certain depleted oil fields recovering their reserves. However, for the future of humanity, it may be prudent to be conservative, and the development of new energy sources is undoubtedly advantageous.

Ancient plants and animals, after death, undergo decomposition and transformation. The impurities resulting from decomposition are washed into rivers, marshes, and lakes by rainwater, river currents, and flash floods. In stable water bodies such as lakes, river mouths, and swamps, they gradually settle and become sediment— even today, the bottoms of rivers, lakes, and river deltas remain dark and foul-smelling with decaying sediment, necessitating periodic and timely dredging.

Rich in organic matter, the underwater sediment

In ancient times, there was no dredging, and sediment continued to accumulate for millions of years. Even if only 1 mm of sediment accumulated on average each year, it would be sufficient to accumulate a thickness of 1000 meters in a million years (a geological basic unit). However, the lifespans of terrestrial rivers, lakes, and swamps are generally not that long, typically lasting tens of thousands to hundreds of thousands of years.

As the Earth evolved, the landscape changed dramatically, and what were once river deltas, lakes, and swamps turned into land. The accumulated sediment was buried underground, and as the overlying layers became thicker and heavier, the sediment gradually compacted into rocks.

If the underwater substrate was originally sandy, organic material would compact with the sand to form sandstone; if it was gravelly, it would become conglomerate; and if it was mud, it could potentially compact into shale.

Organic matter within sandstone, shale, and conglomerate gradually transforms into petroleum under high temperature and pressure.

If geological conditions are suitable, and a trap is formed, petroleum can be stored until it is extracted by humans. However, most terrestrial oil and gas resources are lost due to geological changes as they fail to form traps.

The above describes the formation of petroleum in continental sedimentary strata.

As for marine sedimentary strata, the conditions are even more favorable than those on land. The sedimentation time on the seabed is generally longer than on land, resulting in thicker oil reservoirs.

In China’s southwestern region, 250 million years ago it was a sea (the ancient Tethys Ocean), 200 million years ago it became a landlocked lake, and 70 million years ago it turned into dry land. There are both oil and gas resources formed by ancient marine sedimentation and those formed on land.

Petroleum’s origin, without a doubt, cannot be animal corpses.

The most plausible explanation is the evolution of ancient algae corpses.

Here are the reasons:

1. Algae were one of the earliest types of aquatic plants to evolve. They have a simple structure, thrive in aquatic environments, reproduce rapidly, and can accumulate layer upon layer of algae corpses underwater.

   The accumulation of this “organic matter” in depths of dozens to hundreds of meters is common, and in some places, it can even reach thicknesses of over a thousand meters.

   Organic matter accumulation not only leads to the formation of petroleum but can also become soil, and in certain areas, it can transform into incredibly fertile “black soil.”

   Therefore, in terms of the scale of organic matter, algae align with the burial conditions of the vast majority of petroleum deposits, making them the primary suspect in petroleum production.

2. Algae from hundreds of millions of years ago had relatively few species and similar structures.

   Algae align with the relatively uniform composition of petroleum.

3. Although algae may seem inconspicuous, they are the only type of plant capable of significantly altering the composition of Earth’s atmosphere and climate temperature on a large scale.

   The influence of algae fully matches the power of petroleum.

   Algae, with their rapid life cycles, efficient photosynthesis, carbon fixation, nitrogen fixation, and oxygen production, have repeatedly brought the Earth into ice ages.

   Imagine this,
   In the ancient times when bacteria had not yet evolved the ability to “decompose leaves,” how could this plant not leave behind some “souvenirs” for the Earth?

   Therefore, petroleum undoubtedly cannot be formed from animal corpses; this goes against common sense.

   Bacteria may evolve faster than plants, but they did not evolve earlier.
   Bacteria coexist with plants; plants adapt to nature, bacteria adapt to plants, and animals need to adapt to both plants and bacteria.
   The evolutionary capacity of animals lags far behind that of plants and even further behind that of bacteria.
   The quantity and concentration of animal corpses simply do not meet the stringent conditions required for petroleum burial.

   So, I can confidently assert that petroleum is the result of ancient algae corpses undergoing geological processes.

I have studied petroleum engineering at the undergraduate, master’s, and doctoral levels. Regarding the origin of petroleum, most people support the organic origin theory, with very few supporting the inorganic origin theory.

The mainstream belief is still the organic origin theory. It primarily involves the deposition of algae, plankton, and the remains of plants and animals at the seabed, deltas, or lake bottoms. These organic materials are compressed by overlying layers, and in oxygen-deprived, high-temperature, high-pressure environments, chemical reactions occur, leading to the formation of hydrocarbons. These hydrocarbons migrate into impermeable rocks (commonly referred to as cap rocks) and accumulate to form oil and gas reservoirs. This viewpoint has been confirmed through experiments and practical evidence.

Of course, there is also the inorganic origin theory, although very few scientists subscribe to it. According to this theory, petroleum is formed through chemical reactions of Earth’s minerals under high-temperature and high-pressure conditions, which can be considered a hypothesis at best.

Coal, on the other hand, is believed to be formed through chemical reactions when forests are buried underground.

I personally support the organic origin theory.

No authoritative journal has ever published statements claiming that petroleum originates from animal corpses.

Just think about it logically; how many animals would have to die in one place, remain dead for hundreds of years, to form an oil field?

Petroleum is derived from ancient plants or algae undergoing transformations.

Ancient deceased organisms can give rise to two types of mineral resources: coal and petroleum.

The primary distinction between the two lies in the fact that coal has an extremely high carbon content and a low hydrogen-oxygen content.

On the other hand, petroleum preserves a relatively balanced proportion of carbon, hydrogen, and oxygen elements from the remains of deceased life.

The reason for this difference is that coal forms on land, while petroleum forms at the bottom of water bodies, primarily in the ocean.

It is widely known that there are no plants in the ocean.

If we classify life forms into two categories, excluding plants, as either animals or non-animals, then it could be argued that petroleum indeed originates from animal remains.

However, it is possible for petroleum to form at the bottom of large terrestrial lakes, where freshwater environments support plant life.

Therefore, the statement that all petroleum originates from animal remains is not entirely accurate.

No, it’s not animal corpses, but the organic remains left behind by countless marine phytoplankton, algae, and other microorganisms over hundreds of millions of years. These organic materials accumulated through deposition, burial, and underwent slow, complex chemical changes at the appropriate temperature and pressure, experiencing an incredibly long period of time to eventually become what we now call petroleum.

Furthermore, I’d like to point out that the debate between organic and inorganic origins rages on online but is largely disregarded within the petroleum industry. There are very few proponents of the inorganic origin theory, and they are mostly confined to the former Soviet Union and, to some extent, within certain circles in China. Having spent over a decade in the oil and gas sector, I’ve never heard of any Chief Geologist or Chief Scientist of a major international oil company (IOC) who subscribes to the inorganic origin theory. This is because this theory simply doesn’t lead to oil discoveries.

I believe the key point lies in which theory can guide oil and gas exploration, and currently, the vast majority of oil and gas fields can be explained by organic origins.

Suppose, one day, the inorganic origin theory can guide oil and gas exploration and achieve significant discoveries. In that case, I believe the industry will also support it. But the reality is that this theory doesn’t lead to oil discoveries, so very few people in the industry pay attention to it.

The United States Northwest Pacific National Laboratory successfully replicated the process of algae turning into petroleum in 2013. By simulating the production environment of crude oil, algae were placed in a sealed reactor and subjected to high temperature and pressure. In just one hour, they were able to produce bio-crude oil that closely resembled conventional crude oil. Other companies like the American Sapphire Energy and the Dutch Royal Dutch Shell have also successfully replicated the process of algae conversion into petroleum. They have identified algae species with high oil production potential, paving the way for commercialization of the oil production process.

Source: Wikipedia

Where Does Underground Oil Come From?

How Do Humans Discover Where Oil Is?
It’s All Related to Fossils

In the process of geological exploration and oil prospecting, we unearth many “priceless treasures” from underground. These are the “living archives” left behind from billions of years ago. Fossils allow us to understand the rich and diverse life and environments of that time and have become the “roadmap” for humans in search of oil.

Studying these fossils can help us determine which geological layers contain oil, guiding drilling operations and the extraction of oil and natural gas to supply countless households in our country.

Today, Little Stone takes you to the Paleontology Exhibition Hall of the Northwest Oilfield for a journey through hundreds of millions of years. Here, more than 200 fossils are preserved, collected by generations of oil exploration and research personnel during field investigations and core drilling. They serve as “signposts” for researchers in search of oil, as the layers that contain oil often have stories to tell through fossils.

After viewing these fossils, which one left the most profound impression on you? Feel free to share your thoughts in the comments section.

Source: [Original Article](Please provide the link to the original article)

In 2022, many countries and regions worldwide discovered “oil.” Is the Earth’s oil really the result of the evolution of animal remains?

Indeed, this question has puzzled many people. Some wonder why, if oil is the result of the evolution of animal remains, there seems to be an ever-increasing amount of oil on Earth.

Even in 2022, we’ve discovered a significant amount of oil. Given the Earth’s history and the abundance of life, it seems improbable that so much oil could have formed naturally. So, what’s the explanation behind this? Let’s delve into these questions one by one.

Oil Discoveries in Multiple Locations in 2022

Let’s start close to home with China’s Jiangsu province, which recently discovered 1.1 billion tons of shale oil. Although it’s called shale oil, it shares fundamental similarities with conventional oil.

Moreover, countries like Russia have also made new discoveries, such as 820 million tons of oil. These findings indicate that oil is quite abundant on our planet.

Oil is often referred to as the “lifeblood of industry,” and its value is indeed significant. However, when oil is first discovered, it’s not ready for use.

Crude oil, natural gas, natural gas liquids, and bitumen are all forms of oil. In everyday language, we often refer to oil and natural gas together, but they exist separately. The primary components of oil are various mixtures of alkanes, cycloalkanes, and aromatic hydrocarbons.

China has a substantial oil reserve, primarily concentrated in basins such as the Bohai Bay, Songliao, Tarim, and Ordos.

In terms of resource distribution, approximately 80% of China’s oil resources are concentrated in shallow (<2000 meters) and middle-depth (2000 meters to 3500 meters) reservoirs, while deep (3500 meters to 4500 meters) and ultra-deep (<4500 meters) reservoirs are less common.

Despite the apparent ease of distribution, China’s oil quality is relatively high. Approximately 63% of the recoverable resources are of excellent quality, 28% are low permeability resources, and 9% are heavy oil. These are rough estimates based on publicly available data.

So, Is Oil Really the Result of Organic Evolution?

This question brings us to the topic of oil depletion. Despite concerns, it’s evident that we continue to discover more oil, and there’s no sign of oil running out.

However, oil prices fluctuate significantly. In scientific terms, there are two main theories regarding the formation of oil: biogenic and abiogenic.

Biogenic Oil Formation

• This theory is widely accepted in the scientific community. Studies of oil suggest that it takes at least 2 million years for oil to form on Earth.

The oldest known oil, dating back around 500 million years, likely formed when a significant amount of plant and animal matter decomposed, mixing with other substances inside the Earth. Over time, under the influence of high temperatures and pressure, oil was eventually produced. This theory is similar to the process of coal formation. Earth has experienced five major mass extinctions, and the remains of these organisms could be a part of what formed oil.

Abiogenic Oil Formation Theory

• This theory proposes that oil is naturally present in significant quantities within the Earth’s crust and forms independently of organic matter. According to its proponent, Thomas Gold, the Earth’s crust contains abundant carbon, which naturally exists in the form of hydrocarbons. Under certain conditions, these hydrocarbons transform into oil. This theory does not rely on organic materials. These two oil theories are still under debate, and there’s no definitive answer in the scientific community.

Will Oil Deplete Eventually?

For oil, we don’t know the total global reserves, nor can we predict whether it will ever run out. What we do observe is an increasing trend in oil discoveries, rather than a decline. So, the question of how long oil will last remains uncertain.

One significant issue associated with oil is pollution, which poses a significant threat to the Earth’s ecosystem. While concerns about oil depletion and scarcity have been raised, pollution is a key reason to reduce oil usage. However, many industries rely on oil, making its usage unavoidable. Unless humanity develops a viable alternative to oil, the likelihood of reducing oil consumption remains minimal.

Let me provide you with an answer that everyone can understand.

You’ve probably seen stagnant water bodies before, which are essentially environments where organic matter is preserved under anaerobic conditions. Petroleum is the result of the transformation of ancient biological materials, not an entire organism but rather the remnants of organic materials that have undergone sedimentation.

Without human intervention, rivers and lakes naturally accumulate organic matter. The water acts as a barrier to oxygen, and over time, layers of sedimentation form geological strata. Through millions of years of geological processes, deep-seated high-temperature and high-pressure conditions cause organic materials to transform into small molecules, which make up the components of petroleum and natural gas.

Within geological strata, there’s water, and similar to how rocks can absorb water, there are nanoscale fissures. Oil and gas within these geological strata tend to rise. When they encounter exceptionally dense geological formations, they cease to rise and accumulate, forming oil reservoirs. This process is quite lengthy, taking tens of millions to hundreds of millions of years.

Relatively recent layers of sediment are what we call shale oil deposits. These sediment layers are compacted over time, resembling the pages of a book, hence the term “shale oil.”

Consider the span of human civilization, which is just a few thousand years. Now, imagine the Earth’s age, which is billions of years. From the emergence of life to the present, hundreds of millions of years have passed, allowing for the accumulation of substantial organic materials.

In domestic oil exploration, the process follows a similar theory. Seismic surveys initially provide geological profiles, and researchers examine whether there are source rocks (ancient mud layers), reservoir rocks (rocks with gaps), and cap rocks (dense rocks that prevent oil and gas from rising). All three components are essential for oil reserves to exist. There are numerous exploration methods, including physical, chemical, and biological approaches.

When petroleum volatile compounds reach the Earth’s surface, we observe phenomena like the “Flaming Mountains” mentioned in the classic Chinese tale “Journey to the West.” In ancient times, people who didn’t understand the process believed that these fires were caused by Taoist alchemists, but they are, in fact, natural occurrences.

Have you heard of water hyacinths?

Without interference, these plants, known as water hyacinths, can proliferate on the water surface, spreading until they cover entire bodies of water.

Consequences①: Lakes covered completely (regardless of size)

Consequences②: Depletion of oxygen underwater, blocking sunlight, turning the whole sealed lake into a dead zone

Consequences③: After the water hyacinths die, they sink to the oxygen-depleted lake bottom, where they cannot fully decompose and begin to accumulate.

Throughout Earth’s history, similar plants like water hyacinths have obscured lakes for tens of millions of years, accumulating layers several hundred meters thick. This efficiency surpasses the aggregation of animal remains.

They are likely a primary source of petroleum.

Among the various explanations for the origin of petroleum, I find this one the most reasonable because the phenomenon of water hyacinths can be observed firsthand.

In my hometown, the riverbeds are covered with these plants. The original aquatic plants on the riverbed have died due to being shaded from sunlight by the water hyacinths. If the river’s surface were completely sealed, no vegetation could grow beneath the water hyacinths, and the fish in the water would slowly suffocate (currently, the river’s surface cannot be entirely sealed, so there are still some fish, but the absence of aquatic plants in shaded areas is a fact).

Imagine ancient Earth, where similar surface-dwelling plants occupying large lakes for tens of millions of years. How much petroleum raw material could accumulate?

The size of petroleum reserves likely depends on the initial size of the lakes, with the decay of surface-dwelling plants over the years, gradually being buried underground and transformed into petroleum…

Of course not. The most abundant self-synthesized organic material in the region is algae, and while there may be animal remains, their proportion is far smaller compared to algae and plants. It’s reasonable to say that ancient algae left behind a significant number of remains in the absence of decomposers and transformed into the majority of the Earth’s petroleum during geological processes. However, the contribution of animals to petroleum is definitely negligible.

I’m not a geologist or a petroleum expert. I just want to ask, why did ancient animals collectively die in the Middle East?

The Origin of Petroleum: A Debate

Petroleum is the most widely used source of energy and a crucial raw material in today’s world. However, the debate over the origin of petroleum has persisted for over a century, with two prominent theories proposed by Russian scientists in the 19th century - the organic and inorganic theories. These theories have divided scholars into distinct camps, and the debate remains unresolved.

The Organic Theory

The first attempt to explore the origin of petroleum was made by the Russian scientist Mikhail Lomonosov in 1763. He believed that petroleum and related substances, such as oil shale, carbon, bitumen, and amber, originated from ancient plants. According to him, oil shale was essentially decomposed grass and leaves washed down by rainwater from forests, forming black soil that settled at the bottom of lakes. Lomonosov argued that the lightweight and combustible nature of resin and petroleum indicated a common origin.

Over the years, variations of the organic theory emerged, suggesting that petroleum could form from the remains of marine and terrestrial organisms. It was later proposed that a combination of land and aquatic biota, particularly plankton, played a vital role in petroleum formation. These organic materials, along with sediments and minerals, accumulated in shallow seas, bays, or lakes, creating an oxygen-depleted environment conducive to the transformation of organic matter into petroleum and natural gas through various geological processes.

The Inorganic Theory

In contrast, the inorganic theory, first proposed by Dmitry Mendeleev in 1876, suggests a different origin for petroleum. According to this theory, the Earth contains abundant iron and carbon, which, during the early stages of Earth’s formation, could have synthesized into hydrocarbons through reactions with superheated underground water. These hydrocarbons, similar to petroleum, might have migrated to suitable reservoirs and condensed to form petroleum deposits.

Additionally, there was a belief that some petroleum-like compounds could be produced within the Earth’s mantle through chemical reactions, a theory referred to as the “magmatic theory.” This theory proposes that hydrocarbons could be generated during the cooling and crystallization of molten rocks in the Earth’s interior.

Controversy Persists

Despite the ongoing debate, it’s important to note that the mainstream view in the petroleum industry still leans toward the organic theory. This perspective suggests that petroleum primarily originates from the remains of ancient life forms, with significant contributions from marine plankton. However, the inorganic theory has not been entirely dismissed, and proponents argue that it may account for certain petroleum reservoirs' unique characteristics.

In conclusion, the origin of petroleum remains a subject of scientific debate, with both organic and inorganic theories offering their own explanations. The distribution of oil reserves around the world further complicates this puzzle, with the Middle East, Central and South America, and North America being major contributors to global petroleum resources.

Table 1: Petroleum Reserves by Country

Rank	Country	Proven Reserves (Billions of Barrels)	Percentage of Global Reserves
1	Venezuela	300.9	17.63%
2	Saudi Arabia	266.5	15.61%
3	Canada	171.5	10.05%
4	Iran	158.4	9.28%
5	Iraq	153.0	8.96%
6	Russia	109.5	6.41%
7	Kuwait	101.5	5.95%
8	UAE	97.8	5.73%
9	Libya	48.4	2.83%
10	USA	48.0	2.81%
11	Nigeria	37.1	2.17%
12	Kazakhstan	30.0	1.76%
13	China	25.7	1.50%
14	Qatar	25.2	1.48%
15	Brazil	12.6	0.74%
Total	Global	1586.1	92.9%

Distribution of Petroleum Reserves

• Approximately 75% of the world’s petroleum resources are concentrated in the Eastern Hemisphere, with the remaining 25% in the Western Hemisphere.
• Most petroleum resources are concentrated in the Northern Hemisphere.
• The latitude bands of 20°-40° and 50°-70° in the Northern Hemisphere hold a significant portion of the world’s petroleum reserves.

Regional Breakdown

• Africa has witnessed substantial growth in oil reserves and production in recent years, with countries like Libya, Nigeria, Algeria, Angola, and Sudan being significant contributors.
• North America is rich in oil reserves, particularly in Canada and the United States. However, the United States remains a major oil importer due to high consumption.
• Central and South America, led by Venezuela and Brazil, also have significant petroleum reserves.
• The Asia-Pacific region, including China and India, is experiencing growth in both oil reserves and consumption. China, in particular, has become a major player in the global petroleum industry.
• The Middle East, especially the Persian Gulf region, boasts the largest proven petroleum reserves globally, with countries like Saudi Arabia, Iran, Iraq, Kuwait, and the UAE holding the majority.

Conclusion

While the debate over the origin of petroleum continues, the global distribution of proven reserves highlights the strategic importance of the Middle East in the world’s oil supply. Other regions, such as Central and South America, North America, and Africa, also play vital roles in meeting the world’s energy needs. Despite the ongoing scientific discourse, petroleum remains an indispensable resource for the global economy.

The Origin of Petroleum: A Debate

Petroleum is the most widely used source of energy and a crucial raw material in today’s world. However, the debate over the origin of petroleum has persisted for over a century, with two prominent theories proposed by Russian scientists in the 19th century - the organic and inorganic theories. These theories have divided scholars into distinct camps, and the debate remains unresolved.

The Organic Theory

The first attempt to explore the origin of petroleum was made by the Russian scientist Mikhail Lomonosov in 1763. He believed that petroleum and related substances, such as oil shale, carbon, bitumen, and amber, originated from ancient plants. According to him, oil shale was essentially decomposed grass and leaves washed down by rainwater from forests, forming black soil that settled at the bottom of lakes. Lomonosov argued that the lightweight and combustible nature of resin and petroleum indicated a common origin.

Over the years, variations of the organic theory emerged, suggesting that petroleum could form from the remains of marine and terrestrial organisms. It was later proposed that a combination of land and aquatic biota, particularly plankton, played a vital role in petroleum formation. These organic materials, along with sediments and minerals, accumulated in shallow seas, bays, or lakes, creating an oxygen-depleted environment conducive to the transformation of organic matter into petroleum and natural gas through various geological processes.

The Inorganic Theory

In contrast, the inorganic theory, first proposed by Dmitry Mendeleev in 1876, suggests a different origin for petroleum. According to this theory, the Earth contains abundant iron and carbon, which, during the early stages of Earth’s formation, could have synthesized into hydrocarbons through reactions with superheated underground water. These hydrocarbons, similar to petroleum, might have migrated to suitable reservoirs and condensed to form petroleum deposits.

Additionally, there was a belief that some petroleum-like compounds could be produced within the Earth’s mantle through chemical reactions, a theory referred to as the “magmatic theory.” This theory proposes that hydrocarbons could be generated during the cooling and crystallization of molten rocks in the Earth’s interior.

Controversy Persists

Despite the ongoing debate, it’s important to note that the mainstream view in the petroleum industry still leans toward the organic theory. This perspective suggests that petroleum primarily originates from the remains of ancient life forms, with significant contributions from marine plankton. However, the inorganic theory has not been entirely dismissed, and proponents argue that it may account for certain petroleum reservoirs' unique characteristics.

In conclusion, the origin of petroleum remains a subject of scientific debate, with both organic and inorganic theories offering their own explanations. The distribution of oil reserves around the world further complicates this puzzle, with the Middle East, Central and South America, and North America being major contributors to global petroleum resources.

Table 1: Petroleum Reserves by Country

Rank	Country	Proven Reserves (Billions of Barrels)	Percentage of Global Reserves
1	Venezuela	300.9	17.63%
2	Saudi Arabia	266.5	15.61%
3	Canada	171.5	10.05%
4	Iran	158.4	9.28%
5	Iraq	153.0	8.96%
6	Russia	109.5	6.41%
7	Kuwait	101.5	5.95%
8	UAE	97.8	5.73%
9	Libya	48.4	2.83%
10	USA	48.0	2.81%
11	Nigeria	37.1	2.17%
12	Kazakhstan	30.0	1.76%
13	China	25.7	1.50%
14	Qatar	25.2	1.48%
15	Brazil	12.6	0.74%
Total	Global	1586.1	92.9%

Distribution of Petroleum Reserves

• Approximately 75% of the world’s petroleum resources are concentrated in the Eastern Hemisphere, with the remaining 25% in the Western Hemisphere.
• Most petroleum resources are concentrated in the Northern Hemisphere.
• The latitude bands of 20°-40° and 50°-70° in the Northern Hemisphere hold a significant portion of the world’s petroleum reserves.

Regional Breakdown

• Africa has witnessed substantial growth in oil reserves and production in recent years, with countries like Libya, Nigeria, Algeria, Angola, and Sudan being significant contributors.
• North America is rich in oil reserves, particularly in Canada and the United States. However, the United States remains a major oil importer due to high consumption.
• Central and South America, led by Venezuela and Brazil, also have significant petroleum reserves.
• The Asia-Pacific region, including China and India, is experiencing growth in both oil reserves and consumption. China, in particular, has become a major player in the global petroleum industry.
• The Middle East, especially the Persian Gulf region, boasts the largest proven petroleum reserves globally, with countries like Saudi Arabia, Iran, Iraq, Kuwait, and the UAE holding the majority.

Conclusion

While the debate over the origin of petroleum continues, the global distribution of proven reserves highlights the strategic importance of the Middle East in the world’s oil supply. Other regions, such as Central and South America, North America, and Africa, also play vital roles in meeting the world’s energy needs. Despite the ongoing scientific discourse, petroleum remains an indispensable resource for the global economy.

** Title

A friend of mine graduated from the Petroleum Institute, and he mentioned that their textbooks have been updated. The definition of petroleum has changed, and it’s no longer described as the evolution of animal remains; it’s now referred to as XXX within the Earth’s crust.

XXX, because I’ve forgotten the exact wording~~