It takes advanced physics, mathematics and extensive geological knowledge, as well as sophisticated seismographic technology to locate petroleum-rich formations. Today, petroleum geologists operate with incredible efficiency and accuracy. Once found, the formation’s precise location is marked using GPS coordinates.
Once the legal boundaries of a given tract of land have been determined, the landowner is contacted by a landman. Landmen are specifically trained representatives of oil and natural gas producers tasked with contacting landowners, negotiating and contracting the right to drill and produce minerals over a given term. Depending on the site, any environmental impact studies are conducted at this time.
State and federal land-use laws limit the number and location of wells. Landowners reach an agreement on sharing the drilling expenses, or leasing access and the right to drill and produce their property in exchange for a royalty interest (percentage) of the value of oil or natural gas produced. Water rights are also secured at this step. Once all parties have reached an agreement, permits are granted and legally approved.
The area where the well will be located – known as the drilling pad – is cleared and leveled and gravel roads are built to allow access for heavy equipment. It takes plenty of water to drill a well. A nearby source is located, or a water-well is drilled for use at the site. Then, a pit is dug adjacent to the drilling rig and lined with heavy plastic. This pit will be used to deposit drilling mud – a precise mixture of water, chemicals and weighting agents such as bentonite clay, which suspend rock cuttings while they are brought to the surface and screened out. Next, several holes are dug where the drilling rig will stand. Once the exact location of the wellbore is located, a rectangular space is carved out around it to allow space for workers and drilling tools.
Once all the equipment is set up on site the truly hard work begins. And every step of the way involves constant safety checks and inspections. In fact, there is no higher priority at the drilling site than worker safety. Several layers of protective steel casing and concrete are built around the wellbore and far below the water table beneath. The average depth of a well is 1.5 miles below the surface, and depending on the formation several horizontal wells can be drilled using the same wellbore – a huge savings in time and capital, not to mention land and natural resources.