Southeastern New Mexico Water Quality
Groundwater (GW) and produced water (PW) databases were used to create maps of the
groundwater chemistry of geologic formations. Although trends are present, water
quality in both databases is highly variable within formations and short sampling
The groundwater database contains samples from formations at or near the surface,
and most of the samples are relatively fresh (less than 3000 TDS.) The produced
water database samples are from the deep basin, and have higher salinity, with TDS
up to 400,000 mg/L.
The purpose of this mapping is to find the geochemical distributions and trends
of solutes, and to discover where, and in which formations, groundwater flushing
(in which relatively fresh water moves through a formation, eventually replacing
the original saline brine) is taking place in the Permian Basin of southeastern
The work of previous investigators, together with hydrogeological data gathered
in the course of this project, have indicated that several patterns of water movement
should be expected. These include:
Although there is a large amount of variability between samples, these trends are
born out in general. A major exception is the presence of brines within the Ordovician
despite its carbonate composition; this is because the Ordovician is cut off from
the recharge zone by a major fault zone (the Central Basin Platform) and is not
vertically connected with the upper formations.
- eastward regional flow;
- relatively high flow through highly fractured carbonates such as the reef zones
in the Capitan and Abo, and regionally extensive carbonates such as the Mississippian
- more intermediate flow rates through carbonates with interbedded shales such
as the Pennslyvanian and Wolfcamp;
- low flow rates through formations with variable lithology including carbonates,
evaporites, redbeds, and shales, including the Artesia Group and Upper Leonardian
- The Delaware Mountain Group and Ochoan formations, composed of low permeability
fine-grained sandstone, and evaporites respectively, are expected to have very low
flow rates and briney waters.
The Permian Basin in southeast New Mexico is complex both geologically and hydrologically.
The basin lithology and history, combined with the interaction of groundwater as
it moved through the deep basin aquifer through geologic time, has greatly influenced
the chemical characteristics of waters within the basin in a reasonably consistent
and predictable fashion. The uplift and eastward tilting of the area in the late
Tertiary and Quaternary is likely the cause of much of the chemical distribution
of the waters that we see today, although it is impossible to tell the timing of
groundwater flushing without more detailed chemical analyses and modelling.