Oil and gas are usually far beneath the ground, perhaps even several kilometres down. Finding oil is a difficult task. It's like a treasure hunt, oil companies must hunt for clues that suggest where oil might be found. The people hired are geologists and geophysicists. Geologists study the earth's crust and its history.
Geophysicists make pictures of the rock formations beneath the surface of the earth.
Luckily for us, most of Alberta is mostly covered with sedimentary rocks. This is why Alberta has most of Canada's oil and gas. Geologists look at aerial photographs of the land's surface to look for areas that might have oil. Geologists chip pieces of rock from the ground and study them. Geophysicists use very sensitive instruments called magnetometers and gravitometers to make maps of the rocks below the ground.