The methods of finding and producing oil and gas have come a long way from the “boom town” days when wells were drilled for the most part on pure hunches and hopes. The exploration and exploitation of petroleum are now highly specialized technologies. All branches of the geologic and geophysical sciences are brought into play to piece together a comprehensive picture of all the factors which may have made a certain area favorable for the accumulation of oil or gas. These factors include such things as the age, thickness, and permeability of the sedimentary rocks, the structure, old shorelines, and buried reefs. Once a target is selected, a drilling rig is moved onto the location to prove or disprove the theory. This is the costly step of finding oil. A single 10,000-foot hole may cost $350,000, and some individual wells in New Mexico have cost more than $1 million to drill. If the well is in a completely untested area, it is called a “wildcat.” Once a discovery is made, then the land around the wildcat is explored by “offset” wells until the complete extent of the new field is proved. During 1962, 1666 wells were drilled to an average depth of 5153 feet. The average drilling cost was $71,000 a well, representing a total investment of almost $120 million in a single year! Most of these wells were of the development (offset) type, but even then, 27 per cent were dry. During 1962, 295 true wildcats were drilled; of these, only 46 found oil or gas—about two out of every thirteen. The story of oil just begins with the discovery of a well. Various special “completion” operations are applied to the oil-producing horizon so as to increase the flow into the well. The most common techniques are either by “acidizing,” pumping acid into the formation to increase flow by enlarging the pores in the rock, or by “hydrafracing,” whereby actual cracks are induced in the formation by pumping oil from the surface back into the well under very high pressure. After the well is “completed,” it may be a natural-flowing well if sufficient gas is associated with the oil. If sufficient gas is not present, then the well is pumped. In recent years, considerable success has been achieved in revitalizing old fields where production had dropped below the point of economic operation. These fields are reactivated by forcing either water or gas down selected wells within the field, thereby forcing stagnated oil within the producing zone toward the other wells. This technique is called _secondary recovery_. Many fields will produce more oil under the secondary recovery program than they did during their primary life. [Illustration: Here’s a wildcat for you!]