India had 38 trillion cubic feet (Tcf) of proven natural gas reserves as of January 2007.The total gas production in India was about 31,400 mcm in 2002-03 compared with 2,358 mcm in 1980-81. At this production level, India's reserves are likely to last for around 29 years; that is significantly longer than the 19 years estimated for oil reserves. Almost 70% of India�s natural gas reserves are found in the Bombay High basin and in Gujarat.
Offshore gas reserves are also located in Andhra Pradesh coast (Krishna Godavari Basin) and Tamil Nadu coast (Cauvery Basin).
Onshore reserves are located in Gujarat and the North Eastern states (Assam and Tripura).
India is currently implementing about 14,000 km of natural gas pipelines projects, which is in addition to over 11,000 km of existing cross-country pipelines. Another 14,000 km of pipelines infrastructure is under various stages of implementation,.
The development of pipeline infrastructure is an on going process which will progress with increase in demand of natural gas. The government has initiated multi-pronged measures to increase availability of natural gas in the country including intensifying domestic exploration and expeditious production of coal bed methane (CBM).
What is Natural Gas?
Natural gas is a vital component of the world's supply of energy. It is one of the cleanest, safest, and most useful of all energy sources. Despite its importance, however, there are many misconceptions about natural gas. For instance, the word 'gas' itself has a variety of different uses, and meanings. When we fuel our car, we put 'gas' in it. However, the gasoline that goes into your vehicle, while a fossil fuel itself, is very different from natural gas. The 'gas' in the common barbecue is actually propane, which, while closely associated and commonly found in natural gas, is not really natural gas itself. While commonly grouped in with other fossil fuels and sources of energy, there are many characteristics of natural gas that make it unique. Below is a bit of background information about natural gas, what it is exactly, how it is formed, and how it is found in nature.
Natural gas is a combustible mixture of hydrocarbon gases. While natural gas is formed primarily of methane, it can also include ethane, propane, butane and pentane. The composition of natural gas can vary widely, but below is a chart outlining the typical makeup of natural gas before it is refined.
Typical Composition of Natural Gas
| Methane | CH4 | 70-90% |
| Ethane | C2H6 | 0-20% |
| Propane | C3H8 | |
| Butane | C4H10 | |
| Carbon Dioxide | CO2 | 0-8% |
| Oxygen | O2 | 0-0.2% |
| Nitrogen | N2 | 0-5% |
| Hydrogen sulphide | H2S | 0-5% |
| Rare gases | A, He, Ne, Xe | trace |
In its purest form, such as the natural gas that is delivered to your home, it is almost pure methane. Methane is a molecule made up of one carbon atom and four hydrogen atoms, and is referred to as CH4. The distinctive “rotten egg” smell that we often associate with natural gas is actually an odorant called mercaptan that is added to the gas before it is delivered to the end-user. Mercaptan aids in detecting any leaks.
Natural gas is considered 'dry' when it is almost pure methane, having had most of the other commonly associated hydrocarbons removed. When other hydrocarbons are present, the natural gas is 'wet'.
Found in reservoirs underneath the earth, natural gas is often associated with oil deposits. Production companies search for evidence of these reservoirs by using sophisticated technology that helps to find the location of the natural gas, and drill wells in the earth where it is likely to be found.
Once brought from underground, the natural gas is refined to remove impurities such as water, other gases, sand, and other compounds. Some hydrocarbons are removed and sold separately, including propane and butane. Other impurities are also removed, such as hydrogen sulphide (the refining of which can produce sulphur, which is then also sold separately). After refining, the clean natural gas is transmitted through a network of pipelines, thousands of miles of which exist in the India alone. From these pipelines, natural gas is delivered to its point of use.
The Formation of Natural Gas
Natural gas is a fossil fuel. Like oil and coal, this means that it is, essentially, the remains of plants and animals and microorganisms that lived millions and millions of years ago. But how do these once living organisms become an inanimate mixture of gases?
There are many different theories as to the origins of fossil fuels. The most widely accepted theory says that fossil fuels are formed when organic matter (such as the remains of a plant or animal) is compressed under the earth, at very high pressure for a very long time. This is referred to as thermo genic methane. Similar to the formation of oil, thermo genic methane is formed from organic particles that are covered in mud and other sediment. Over time, more and more sediment and mud and other debris are piled on top of the organic matter. This sediment and debris puts a great deal of pressure on the organic matter, which compresses it. This compression, combined with high temperatures found deep underneath the earth, breaks down the carbon bonds in the organic matter. As one gets deeper and deeper under the earth’s crust, the temperature gets higher and higher. At low temperatures (shallower deposits), more oil is produced relative to natural gas. At higher temperatures, however, more natural gas is created, as opposed to oil. That is why natural gas is usually associated with oil in deposits that are 1 to 2 miles below the earth's crust. Deeper deposits, very far underground, usually contain primarily natural gas, and in many cases, pure methane
How Natural Gas is Measured?
Natural gas can be measured in a number of different ways. As a gas, it can be measured by the volume it takes up at normal temperatures and pressures, commonly expressed in cubic feet. Production and distribution companies commonly measure natural gas in thousands of cubic feet (Mcf), millions of cubic feet (MMcf), or trillions of cubic feet (Tcf). While measuring by volume is useful, natural gas can also be measured as a source of energy. Like other forms of energy, natural gas is commonly measured and expressed in British thermal units (Btu).
What is British thermal units (Btu)?
One Btu is the amount of natural gas that will produce enough energy to heat one pound of water by one degree at normal pressure. To give an idea, one cubic foot of natural gas contains about 1,027 Btus. When natural gas is delivered to a residence, it is measured by the gas utility in 'therms' for billing purposes. A therm is equivalent to 100,000 Btu, or just over 97 cubic feet, of natural gas.
Problems with Natural Gas
- Not a renewable source of energy.
- India has only limited reserves of natural gas, though further discoveries are being made from recent explorations
- Owing to the high percentage of methane in natural gas, it is highly combustible
- The process of extraction of natural gas involves making large cavities in the ground. Natural gas requires highly complex treatment plants and pipelines for its delivery.
- Natural gas occupies four times the space of a gasoline-equivalent energy
Unconventional Natural Gas Resources
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