While many of the world's natural wonders are buckling under various pressures, the Great Barrier Reef has remained one of the most well-preserved coral systems on the planet.

Oil occurs in certain geologic formations at varying depths in the earth's crust, and in many cases elaborate, expensive equipment is required to get it from there. Read below all you need to know about the oil industry in the world.

How much oil is there in the world?

At the end of 2005, world proven crude oil reserves stood at 1,153,962 million barrels, of which 904,255 million barrels, or 78.4 per cent, was in OPEC Member Countries.

How long does it take to discover oil and bring it to market?

There is no standard answer to this question, but as a rule of thumb, it can take 3-10 years from the decision to explore, through to discovery, testing, development and the delivery of oil from a new field.

The time required depends on where the oil is and thus how difficult it is to discover, test and develop.

For instance, an offshore oil field in deep water can take much longer to discover and test, due to the challenging technical requirements. Drilling in deep water is also difficult and can be very expensive, so the explorers need time to raise the necessary money as well as meet the new technical challenges.

Will we ever see a repeat of the 1970s oil crisis?

No. The 1970s oil crisis was a complex affair reflecting issues particular to that time and it is unlikely to be repeated.

Indeed, we all learned a lot from that experience. We know that if oil prices go too high or too low it will be harmful both to oil producers and oil consumers, both in the short- and long-term.

OPEC is dedicated to providing a stable oil market, with reasonable prices and steady supplies to consumers.

Consider the example of the Gulf Crisis in 1990, when production of several million barrels per day of oil from Iraq and Kuwait was suddenly halted, leading to a rapid rise in world oil prices. Those Member Countries not involved decided to increase their oil supplies in order to make up for the shortfall. As a result, oil prices stabilised and came down again to reasonable levels. However, there is always potential for instability in the oil market.

OPEC continues to seek co-operation among all oil producers and consumers. Such co-operation is necessary to ensure stability

What causes low oil prices?

Low prices of crude oil can be caused by a number of factors. Basically, it could be due to an imbalance between supply and demand -- too much supply or too little demand.

OPEC member countries have always tried to adjust their crude oil supplies to improve the balance between supply and demand. OPEC's aim at all times is to maintain steady supplies of oil to consumers, while securing a reasonable return for its Member Countries. However, OPEC cannot be expected to achieve this on its own.

Most non-OPEC oil producers supply as much oil as they can. This makes it difficult for OPEC to maintain stability in the oil market and results in losing market share and potential revenue for the organization.

If oil production rises faster than demand, then prices can fall and all oil producers will suffer. In the long run, consumers will also suffer if the oil industry is unprofitable and unattractive to investors.

What causes high oil prices?

High crude oil prices could be due to a shortage of oil supplies. High prices for oil products -- as purchased by end consumers such as motorists -- are more likely to reflect other factors, such as taxation.

Crude oil prices react to the balance of demand and supply in the short term, and the rate of investment in the longer term. If investment is not made far enough in advance, oil supplies could be limited in the longer term, thus raising prices. Sentiment is also an important factor: if traders in the oil market believe there will be a shortage of oil supplies, they may raise prices before a shortage actually occurs. Other factors influencing the price of crude oil include accidents, bad weather, increasing demand, halting transport of oil from producers, labour disputes (strikes) as well as other disruptions to production including war and natural disasters.

Crude oil now represents less than a quarter of the price of oil products in many countries. Therefore, taxes have more influence over the price of oil products. When oil taxes are raised, end consumers often mistakenly blame the oil producers, but it is really their own governments that are responsible.

OPEC seeks a stable oil market, without sudden price changes or excessively high or low prices. OPEC regularly meets with other oil producers and with consumers in an effort to improve understanding and trust in the oil industry and to seek policies and measures that do not create unnecessary economic hardship for oil producers or consumers.

What happens if oil prices go up or down?

The world lives on oil. Oil is the foundation for the plastics and petrochemical industries. Oil is fundamental to the welfare of the industrialised world and it is a major component of the farming industry.

The price of oil is reflected in most of the things we do. It impacts on the price of transport, the cost of goods and services, and the availability of many products, including food, water and shelter.

If oil prices are too high, then these goods and services become more expensive and economies experience inflation. Alternative forms of energy would also become more cost-competitive, but oil producers would eventually increase their supplies and prices would come back down.

If oil prices are too low, consumers would waste this non-renewable resource, investors would not be attracted to the industry and oil producers would suffer - especially the developing countries that produce oil, such as the OPEC Member Countries. If prices were too low, supplies would eventually fall until there was a price shock -- leading back to inflation.

Oil prices that are too high or too low are clearly unhelpful for oil producers, oil consumers and the world at large. That is why OPEC makes quite sure that the market is not under-supplied with oil, forcing prices to go excessively high, and also that the market is not over-supplied so that prices go too low. It also speaks to other oil producers to encourage them to avoid over-supplying the market. It is also why OPEC talks to oil consumers to encourage them to adopt fair and equitable policies that do not discriminate against oil.

We would all suffer without steady supplies of oil at stable, reasonable prices.

How much oil does the world consume each day?

According to the reference case of OPEC's World Energy Model, total world oil demand in 2000 is put at 76 million barrels per day, As world economic growth continues, crude oil demand will also rise to 90.6m b/d in 2010 and 103.2m b/d by 2020, according to the OWEM reference case figures.