RE: Well logging/Tracer Operations

["Spell, Bill" <bills@deq.state.la.us>]

Good summary, Wes.  Our e-mail has been down since August 29 until today, 
and I've not received RADSAFE for that period of time.  So, I did not see 
the original post, I think.  About the only  thing you did not cover is what 
happens when sealed sources get stuck downhole and can't be retrieved.  This 
is probably the forerunner of the WIPP facility in the case of Pu-Be and 
Am-Be sources, and it certainly is a form of LLW disposal we don't talk 
about in polite society.  <GRIN>

Not trying to open a can of worms, but whatcha' think?

CULater......

Bill Spell
bills@deq.state.la.us
 ----------
From: radsafe
To: Multiple recipients of list
Subject: RE: Well logging/Tracer Operations
Date: Thursday, September 05, 1996 8:00AM

Actual logging is done with sealed sources (Cs-137 for gamma logs, Am-
241(Be) for neutron logs).  However, they also use various isotopes
for tracer operations to determine oil field flow characteristics.  I-
131 is a very commonly used tracer isotope.  You can put it down this
hole, and monitor another hole to see how the oil moves.

If you have poor flow, you can do a "fracture" job, whereby you push
a lot of Ir-192 tagged sand into the zone, hoping to crack it for
better oil flow.  By monitoring the Ir-192, you can see whether it is
working or not.

If you really want to get complex, you pour different isotopes down
different holes.  This can give you a very good diagram of the field
characteristics.

(Disclaimer: I haven't much effort in this area for some time, so my
descriptions are necessarily general - and I can't find my best
reference book at the moment)

Wes

> Date sent:      Wed, 4 Sep 96 19:08:39 -0500
> Send reply to:  radsafe@romulus.ehs.uiuc.edu
> From:           Slaback@micf.nist.gov
> To:             Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject:        RE: crosspost: OEM: Carcinoid tumour of thymus /
radioisotope exposure

> My first impression is that there is a major
> misunderstanding by this individual.  These
> sources are usually sealed sources so the description
> of 'spilling on clothing...' etc would seem
> erroneous.
>
> Is anyone aware of unsealed usage of these long-
> lived radionuclides in well logging?
> I believe some (tritium?) have been used in
> injection/dilution studies.  Would appreciate
> comments from well logging experts.
>
> A little risk adds spice to life.
> slaback@MICF.NIST.gov
>
*********************************************************************
Wesley M. Dunn, CHP                        512-834-6688
Deputy Director, Licensing                 512-834-6690 (fax)
(Texas) Bureau of Radiation Control        wdunn@brc1.tdh.state.tx.us
*********************************************************************