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.
[Illustration: (_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.
[Illustration: 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.