David Sysyn, age 12, of Ambridge, Penna.his `question:
How is natural gas formed?
Natural gas is given tiff during the formation of petroleum deep in the earth's crust. The process takes millions of years and no one is exactly certain how it occurs. A few chemists suggest that petroleum might, just might, be caused by the break down of certain minerals. But most scientists think that our supplies of petroleum and natural gas were formed from living things.
These life forms, plant and animal, existed in the ancient seas which often slopped over onto what is now dry land. They still teem in the waters. An acre of off shore water may field a ton of protein material which makes it a richer food source than the richest soil. Ooze from the bottom of these shallot sea waters may contain 7% organic matter from these plants and animals.
This organic matter is thought to be the raw material for making oil and natural. gas. When the rocky formation is suitable, pockets of this ooze undergo chemical changes. The process takes millions of years. The result may be an underground sandwich of salt water, petroleum and natural gas. The salt water, being heaviest, is at the bottom. The gas., being lightest, rests on top of the precious petroleum.
A so called pool of oil is nothing like a swimming pool, or even a puddle. The oil is held in porous rocks as in a sponge. The oil pool which survives the ages exists in a rocky trap. There are dense, non¬porous rocks which act as walls to prevent the oil from escaping sideways. There is a dense rocky cap on top of the oil pool which prevents the oil from escaping into the air.
Imprisoned in this rocky trap through countless ages, the oil goes through chemical changes. Petroleum, like any organic matter, is a highly complex mixture of hydrocarbon chemicals. Through the ages, the heavier and lighter substances tend t o sort themselves out. The lighter, gaseous substances rise to the top and free themselves from the oily ooze. They form what we call natural gas, which is always a mixture of gases. The most common is methane or marsh gas, which also escapes from decaying marshes. Thereare varying quantities of ethane, propane, butane, hydrogen, nitrogen, helium and oxides of carbon.
Some of these gases are more valuable to us than others. Helium, for instance, is the only safe lifting gas for balloons. Others are valuable fuel gages. The one separated t o run the kitchen range is methane the same gas which makes the willyo the wisp dace over the swamp. It is often piped hundreds of miles and because it is the most widely used of the petroleum gases, we call it natural gas. The geologists tell us that there are reservoirs of natural gas in 30 of our states. As a fuel, it yields twice as much heat as the best coal.