(19) |
 |
|
(11) |
EP 0 387 055 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
|
10.06.1992 Bulletin 1992/24 |
(43) |
Date of publication A2: |
|
12.09.1990 Bulletin 1990/37 |
(22) |
Date of filing: 08.03.1990 |
|
|
(84) |
Designated Contracting States: |
|
DE FR GB IT NL |
(30) |
Priority: |
10.03.1989 US 321307
|
(71) |
Applicant: HALLIBURTON LOGGING SERVICES, INC. |
|
Houston,
Texas 77042 (US) |
|
(72) |
Inventors: |
|
- Gadeken, Larry L.
Houston,
Texas 77079 (US)
- Smith, Harry D., Jr.
Houston,
Texas 77079 (US)
|
(74) |
Representative: Wain, Christopher Paul |
|
A.A. THORNTON & CO.
Northumberland House
303-306 High Holborn London WC1V 7LE London WC1V 7LE (GB) |
|
|
|
(54) |
Gamma ray well logging for radial tracer distances |
(57) Gamma ray well logging to obtain relative distance indications of tracers from the
well bore comprises separating a measured gamma ray spectrum into component parts
attributable to individual tracers, using standard spectra, and then obtaining the
relative distance indicators from those parts of the spectrum. For cased borehole,
using standard spectra as a guide, the proportions of the borehole component and the
formation component can be determined and a composite spectrum obtained for each individual
tracer by adding the borehole and formation components together. A Compton ratio R
c of gamma ray counts in an energy region of the spectrum which is sensitive to Compton
scattering to gamma ray counts in an energy region of the spectrum which is not sensitive
to Compton scattering is then obtained. By a linear transformation which parameterizes
the Compton ratio R
c with the inverse square of the annulus diameter of a distributed region of tracer
surrounding the well bore, a relative distance indication of the distribution of each
tracer with respect to the well bore is obtainable for each tracer.
