Oil-drilling rigs and gas-drilling rigs are similar in that they both include equipment to create holes in the ground to access deposits of naturally occurring substances; they mainly differ in their extraction tools. An oil-drilling rig includes a series of pumps and pipes to draw the liquid up from the ground, whereas a gas-drilling rig has tools to capture the gas before it leaks out.
The basic concept for all types of drilling rigs is the same, in that they are machines that bore into the sub-surface of the ground to create wells, from which other devices and structures may extract substances. Drilling rigs can vary in size significantly, with some smaller rigs including functionality that allow them to move to different locations. These rigs typically focus on ground sampling and analysis to determine the presence of natural resources, whereas the larger stationary rigs focus on deep drilling to access the deposits.
Many drilling rigs often include special tools for implanting pipes into the wells to allow for the extraction of the material. In most cases, once a company locates a natural resource deposit, it installs a specialized drilling rig to handle the specific material. For example, oil drilling rigs contain special pumps that draw the oil up from the ground, or include devices to fill the well with acid or other materials to cause the oil to move upwards.