Oil and gas touches our life in different ways, it is the major source of energy. Crude oil is defined as a naturally occurring, hummable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds that are found in geologic formations beneath the surface.

FORMATION
All of the oil and gas we use today began as microscopic plants and animals living in the ocean millions of years ago. As these microscopic plants and animals lived, they absorbed energy from the sun, which was stored as carbon molecules in their bodies. When they died, they sank to the bottom of the sea. Over million of years, layer after layer of sediment and other plants and bacteria were formed. As they became burial ever deeper, heat and pressure began to rise. The amount of pressure and degree of heat, along with the type of biomass, determined if the material became oil or natural gas. More heat produced lighter oil. Other oil and natural gas deposits migrate until they were trapped. These trapped deposits are where we find oil and natural gas today.

THE PETROLEUM INDUSTRY
Petroleum Industry is divided into three sectors; the upstream sector, the midstream sector and the downstream sector. Midstream Operations are usually included in the downstream category.
The upstream oil sector is a team commonly used to refer to the searching for and the recovery and production of Crude oil and natural gas. The upstream oil sector is also known as the exploration and production (E&P) sector.

The main characteristics of Crude Oil are:

1. It density in the oil industry, this is usually measured by its API gravity
2. Its Sulphur Content

The downstream oil sector is a term commonly used to refer to the refining of Crude Oil, and the selling and distributing of natural gas and products derived from Crude Oil. Such products include liquefied petroleum gas (LPG), gasoline or petrol, jet fuel, diesel oil, other fuel oils, asphalt and petroleum coke.
The downstream sector includes oil refineries petroleum plants, petroleum product distribution, retail outlets and natural gas distribution companies.

THE UPSTREAM SECTOR
Extraction of Petroleum;
The extraction of petroleum is the process by which usable petroleum is extracted and removed from the earth.

LOCATING THE OIL
Geologists use Seismic Surveys to search for geological structures that may form oil reservoires. The classic method includes making an underground explosion nearby and observing the Seismic response that provides information about the geological structures under the ground. Extracting Crude Oil normally starts with drilling wells into the underground reservoir.

OIL WELL
An Oil Well is a general term for any boring through the earth’s surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A Well that is designed to produce mainly or only gas may be termed a gas well.

LIFE OF A WELL
A schematic of a typical oil well being produced by a pump jack which is used to produce the remaining recoverable oil after natural pressure is no longer sufficient to raise oil to the surface,
The creation and life of a well can be divided up into five segments:

1. Planning
2. Drilling
3. Completion
4. Production
5. Abandonment.

-       THE DOWNSTREAM SECTOR
The Downstream Industry is where petroleum meets you – the consumer. The downstream industry includes Crude Oil Refineries, gas processing plants, petrochemical plants, transportation networks (truck, rail, pipeline and marine), retail gas stations and natural gas distribution companies. Downstream also includes the sales and marketing of reined petroleum products to wholesalers, industrial and commercial customers.

PRODUCTS OF THE DOWNSTREAM SECTOR
The downstream sector provides the thousands of products we use in our everyday lives and there are about 3,000 products made from petroleum. From the moment your alarm wakes you up, you brush your teeth, slip on your runners and pump up the tires on your bike, you are using petroleum products. Here are just a few of the thousands of products you may use that are made from oil and gas;

• Transportation
• Household Items
• Leisure and Entertainment
• Apparel and Accessories
• Medical and Personal Hygiene.

FRACTIONAL DISTILLATION
 

USES OF LNG IN VARRIOUS SECTORS;

1. Residential Uses
2. Commercial Uses
3. Uses in Industry
4. Electric Generation Using Natural Gas

-       ECONOMIC BENEFITS OF CRUDE OIL AND GAS
Oil is a major source of energy in Nigeria and the world in general. Oil being the mainstay of Nigerian Economy plays a vital role in shaping the economic and political destiny of the country.
            Over the years the oil industry has made a variety of contributions to the Nigerian Economy. These have included the creation of employment opportunities.

CONTRIBUTIONS BY THE OIL INDUSTRY

• Employment Opportunities
• Contribution to Gross Domestic Product
• Local Expenditure on Goods and Services
• Contributions to Government Revenue
• Foreign Exchange Reserves
• Contribution to Energy Supply.