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XI-5
ous accumulation called afield. The pool name is made up of two pans:
1) the field name, usually derived from a geographic location (e.g. Bueno);
2) the stratigraphic name, derived from the stratigraphic unit that acts as
the reservoir for the oil and/or gas (e.g. San Andres).
In this hypothetical example, the field name is Bueno and the pool name is Bueno
San Andres. Other pools in this field are Bueno Abo, Bueno Upper Silurian,
Bueno Montoya, and Bueno Ellenburger. This definition of pool is consistent with
regulatory and legal usage in New Mexico.
Reservoir: A layer or stratum of.porous and permeable rock in which crude oil,
natural gas; or natural gas condC"nsate are found and can be produced in economic
quantities. This definition is consistent with regulatory and legal usage in New
Mexico.
Methodology of resource estimation - primary recovery
Numerical estimates of crude oil, natural gas, and natural gas condensate resources
recoverable through primary production techniques were made by geologically
delineating areas of probable production. Historical production data from producing wells
were used to calculate the volume of oil, gas, and gas condensate recoverable per unit
area of reservoir. The area within the boundaries of potential production was calculated
and multiplied by recoverable resource per unit area to give ultimate recovery. Probable
resources of a pool are obtained by subtracting cumulative production from ultimate
recovery.
Basic information for all wells drilled for oil and gas in a nine-township study
area centered on the WIPP site (Fig. 2) was compiled from well records on file at the
Subsurface Library of the New Mexico Bureau of Mines & Mineral Resources. Geophysical
borehole logs were analyzed and correlated throughout the nine-township study area.
Log correlations were used to produce structure contour maps of appropriate mapping
datums and to isopach the primary pay zones in pools adjacent to the WIPP land
withdrawal area. Structure contour maps were made of four stratigraphic surfaces, the
structure of which may govern hydrocarbon entrapment in major producing reservoirs.
These four surfaces are: 1) a prominent resistive log marker at the top of the lower
Brushy Canyon Formation; 2) the top of the Wolfcamp; 3) the top of the Strawn Group;
and 4) the top of the Morrow clastic section. Because of inaccuracies inherent in stratigraphic
data obtained from scout cards and the omission of stratigraphic tops from many
scout cards, log correlations made during the coUrse of this study were used to calculate
subsea levels necessary for contouring. Other maps unique to the analysis of each pool
were also produced and are discussed at appropriate places below. These other maps, in
conjunction with the appropriate structure contour maps, were then utilized to project the
boundaries of known (i.e. discovered) hydrocarbon traps into undrilledlnonproductive
areas beneath the WIPP land withdrawal area and the surrounding one-mile wide study
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