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

I. Special "Down Hole" Swvcys
special "Down Hole" surveys must be approved in advance by mc in Austin. for a speclfic
wellbore unless they are expressly required by the injection/disposal authority.
A. Radioactive Tracer SUI'VC}': fluid Is pumped into well at the maximum pennltted .
injection pressure. Radioactive Iodine Is ejected into the flow at various depths, from the
ground surface through the injectlon perforations. and is measured as It flows down the
wellbore. If any radioactive material leaves the wellbore, the measuring tool w1lllose
contact with it. or record a not spot" where the radioactive mater1alls leaking from the
wellbore.
B. Spinner or Flow Meter Surrey: fluid is pumped into the wen at a fixed rate. A flow
measuring tool is used to measure the volume' of fluid flow across the welIbore. A'
decrease of flow volume usually indicates a casing leak or perforations. This method Is
usually'used in conjunction with other tools due to a lack. of sensitivity.
C. Differential Temperature Log: After normal injection activity, a water injection
well is shut-in for twelve (12) to efghteen (IS) hours, a gas Injection wen is shut-in for
one (1) to four (4) hours. DuriDg the logging process. the geothermal gradient. and the
rate at which that gradient Is cbangtng (differential),arerecordedfromgroundsurface
through the injection perforations. Abrupt shifts in temperature readings indicate
possible wellbore integrity problems and will need further testing to prove Integrity and
allow continued injection activity.
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