(GP/GT) for Additional Water Supply in the Lower Rio Grande

ill-24
III. B-2
BRINE DISPOSAL VIA INJECTION INTO
APPLICABLE UNDERGROUND FORMATIONS
In a major oil and gas producing State such as Texas, the framework and procedures for proper
underground disposal of brines are inherent in hydrocarbon production regimes.
Thousands of disposal permits have been issued by the Texas Railroad Commission (TRC), which has
principal jurisdiction over this alternative for brine disposal. There are four major parameters for
allowable underground disposal that are key to the acquisition of an appropriate disposal permit, namely:
A. Proper analyses of existing well logs to select receiving formations
B. Porosity, permeability and reservoir capacity data in selected formations
C. Proper design of injection well(s) and surface systems
D. Pressure and flow constraints for intended pumping rates into receiving formations
Certain other constraints may also be relevant but, in general, satisfaction of the above four parameters
is generally tantamount to permit approval.
Certain factors unique to GP/GT brines are also significant in reservoir evaluation prior to selection of
the proper receiving formations. These are the temperatures and flow rates of the brines in question and
the necessity to plan for adequate reservoir capacity in a given formation, such that disposal may proceed
over a reasonably long period of time, at least ten years.
A good preliminary idea of the capacity of some South Texas receiving formations may be derived from
referring back to the introduction to this Section ill B, on page 16, wherein a professional, independent
organization active in brine disposal has stated that: "injection of 20,000 BBLlDay into five 6,000 foot
wells of reasonable cost is possible.... If operated for 15 years, the receiving reservoir will need to store
2.2 x Hf BBL". In TWOB terms, that quantity equals 285,000 acre-feet over 15 years, or roughly a
little less than 2,000 acre-feet per year.
The qualifying procedures and other relevant details are herein excerpted and reproduced from the TRC
Manual entitled: "Underground Injection Control Reference Manual", April 1992 Revision. (please refer
to Appendix B).
In summary, Underground Disposal of Brines in Texas is a well formulated and highly standardized
technique that represents a particularly cost-effective and environmentally safe method of brine disposal.