Exploring for Natural Gas
Natural gas can occur alone, or with crude oil. Exploration for natural gas and crude oil are similar activities. Before exploring for natural gas or crude oil in Saskatchewan, permission to do so must be obtained from the provincial government, from the mineral rights owner and from the surface land owner.
Before drilling for natural gas can begin, geologists, geophysicists and geochemists study the proposed drilling site from the air, on the ground and under the ground with drills and other instruments. The searching takes place in sedimentary basins where it is known that marine life lived millions of years ago.
When the scientists find an area that probably contains crude oil and/or natural gas, the region is further investigated using seismic surveys. Seismic surveying in Saskatchewan is relatively easy and inexpensive because of the lack of trees and flat terrain. You often see seismic crews charting the types of rock formations found beneath the ground in order to help determine if it is economically feasible to drill there.
Producing Natural Gas
After the preliminary searching for natural gas, the only way to know for sure if petroleum reservoirs exist beneath the surface of the earth is to drill a well. Statistics show that there is a less than 20% chance that the well will be economically worth the investment.
Drilling is very expensive. Drill bits cut through the rock. Pumps circulate drilling fluid, called mud, down the centre of the drill to cool the drill bit and carry the bits of rock to the surface. During the drilling process, core samples are constantly being taken to determine the type of rock through which the drill bit is moving.
If natural gas is found, a well casing called a Christmas tree are installed. (A Christmas tree is an arrangement of pipes and valves that regulate the flow of natural gas.) Normally, once a well has been drilled and natural gas has been found, natural gas flows to the surface without the aid of pumps. The Christmas tree controls this natural flow.
Natural gas produced at the wellhead contains methane, ethane, propane, butane, and other hydrocarbons. It is odourless and colourless. The industry refers to it as "raw gas".
In order to produce "pipeline quality gas", that is natural gas that can be used by consumers, the "raw gas" must be processed to remove unwanted components, leaving primarily methane.