OIL AND GAS
Most of New Mexico’s oil and gas are produced in the southeastern part, south and east of Roswell. The bustling towns of Hobbs, Artesia, and Lovington, as well as Roswell, are headquarters for the many oil companies and the associated service and supply organizations operating in the area. Oil and gas are produced from numerous reservoirs, called fields or pools, in Paleozoic sediments ranging from Ordovician to Permian in age. From the standpoint of production, the Eunice-Monument field (lying between these two towns) is the largest, having produced more than 250 million barrels of oil. Other important fields are Hobbs, Vacuum, Langlie Mattix, Denton, and Jalmat. All these fields produce a considerable amount of gas associated directly with the oil.
When driving an automobile through southeast New Mexico, a layman finds it difficult to comprehend the immensity of the petroleum industry of that region. This is due to the scattering of wells over a large area. Seldom are wells spaced closer than one to every ten acres, even in the most productive fields. There are, in fact, some 16,000 wells in this part of New Mexico, ranging in depth from less than 1000 feet to 17,555 feet.
The other oil- and gas-producing area of the state is in the northwest, in the San Juan Basin. Farmington serves as the base of operations for most of this activity. In 1962, there were 7378 wells in the area, 1770 of which were producing oil and gas and 5608 producing gas only. Most of the San Juan Basin production is from Cretaceous sandstones, in contrast to the southeast where the oil and gas are derived from Paleozoic sediments. The development of the San Juan Basin production is relatively new; most of the wells have been drilled since World War II. The petroleum industry can be proud of the great help it has given to the development of this once-almost-forgotten part of the state.
(Courtesy El Paso Natural Gas Co.)
There’s the way to refine oil! Look at those mesas, near Gallup
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.
Here’s a wildcat for you!
Once the oil is on the surface, it passes through separators to remove any admixed gas from the oil. The gas is sent into pipelines while the oil is sent to storage tanks called tank batteries. Periodically, the oil is drawn from the tank batteries where it is transported by pipeline or rail to refineries. The great bulk of the crude oil leaves New Mexico for refining via a major pipeline network extending through Texas to both the Gulf and East coasts. Some oil is refined in New Mexico, however. Oil refineries in Artesia, Bloomfield, Ciniza, Farmington, and Monument have a combined capacity to treat some 30,000 barrels (42 gallons a barrel) of crude oil a day. On the other hand, practically all the natural gas is treated in New Mexico so as to recover its liquid petroleum constituents before sending it out of the state by pipeline.