There are different types exploration drilling for oil and gas. There are some areas of the world that you can find oil or gas seeping from the earth’s crust. It may be visible directly or there may be a “pockmark”, which is an indentation in the ocean’s floor that it is created from seeping gas. It is near the surface and has broken through the crust. This is unusual. Normally wells must be drilled to reach oil and gas. This can be an expensive and timely venture. Depending on the type of exploration, an exploration well may or may not be successful.
Technology has advanced in recent years and has made exploration for oil and gas much more efficient and productive. The different methods and types of oil and gas exploration include the following:
• GRAVITY SURVEY – measures the constant downward acceleration of gravity. It can measure the smallest changes. For gravity surveys, the instrument that is used is a gravimetor or a gravitometer.
• MAGNETIC SURVEY – measures the differences in the magnetic fields in the earth. The magnetmeter is used for magnetic surveys.
• PASSIVE SEISMIC SURVEY – it detects low frequency that occurs naturally. Passive seismic surveys are done with seismometers that “listen” over hours or days.
• REFLECTIVE SEISMIC SURVEY – it uses a controlled source of energy to reflect (bounce sound). An air gun or seismic vibrator is used for reflective seismic surveys.
These are exploration methods are known as geophysical explorations.
When a type of exploration results in a “lead” then further exploration is done before drilling begins. This is usually done with more sophisticated seismic exploration is done. Different oil drilling companies have different criteria when it comes to actually starting to drill. When there is a lead in remote areas or if the lead is offshore, smaller oil companies will not be able to finance the drill and larger oil companies will be the ones that will drill the well. Though independent oil companies are responsible for a majority of the oil drilled, they will not usually take on the more expensive drill. There are an abundant number of wells that have not proven productive enough for the larger company, but will still produce significant amounts of oil and/or gas if the well was developed.
Tags: acceleration of gravity, downward acceleration, gravity surveys, independent oil companies, oil drilling companies