CA2349763A1 - Standoff compensation for nuclear measurements - Google Patents
Standoff compensation for nuclear measurements Download PDFInfo
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- CA2349763A1 CA2349763A1 CA002349763A CA2349763A CA2349763A1 CA 2349763 A1 CA2349763 A1 CA 2349763A1 CA 002349763 A CA002349763 A CA 002349763A CA 2349763 A CA2349763 A CA 2349763A CA 2349763 A1 CA2349763 A1 CA 2349763A1
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- Prior art keywords
- segment
- azimuthal
- formation
- detector
- apparent
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V5/00—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity
- G01V5/04—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
- G01V5/08—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
- G01V5/12—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using gamma or X-ray sources
- G01V5/125—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using gamma or X-ray sources and detecting the secondary gamma- or X-rays in different places along the bore hole
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- Physics & Mathematics (AREA)
- High Energy & Nuclear Physics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Geophysics And Detection Of Objects (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
Abstract
A nuclear logging-while-drilling measuring systems, and the correction of the formation property measurements for adverse effects of instrument standoff from the borehole wall, is disclosed. Detector responses for one or more downhole detectors are sampled and recorded over a time segment. The response samples are then sorted by magnitude, and a running integral of the sorted samples as a function of time is performed over the time segment. Linear segments are then fitted to the running integral, wherein each straight line segment is a function of one or more formation properties, and also a function of the standoff distance of the detector from the borehole wall. Segments are then combined to obtain a measure of one or more formation properties of interest, where the adverse effects of borehole standoff are minimized. Standoff magnitude is also obtained. No independent caliper of the borehole is required to perform the standoff correction.
Claims (33)
1. A method for determining a property of earth formation penetrated by a borehole, comprising the steps of:
(a) positioning at least one detector within said borehole;
(b) measuring a plurality of detector responses over a time segment;
(c) sorting said detector responses by magnitude into sorted detector responses;
(d) fitting at least one linear segment to said sorted detector responses as a function of time; and (e) determining said formation property from said at least one linear segment.
(a) positioning at least one detector within said borehole;
(b) measuring a plurality of detector responses over a time segment;
(c) sorting said detector responses by magnitude into sorted detector responses;
(d) fitting at least one linear segment to said sorted detector responses as a function of time; and (e) determining said formation property from said at least one linear segment.
2. The method according to claim 1, further comprising:
computing running integral sums from said sorted detector responses;
computing running integral sums from said sorted detector responses;
3. The method of claim 1 further comprising the steps of:
(a) obtaining at least two linear segments;
(b) determining an apparent formation property from each of said linear segments; and (c) combining a weighted average of each said apparent formation property to determine said formation property.
(a) obtaining at least two linear segments;
(b) determining an apparent formation property from each of said linear segments; and (c) combining a weighted average of each said apparent formation property to determine said formation property.
4 The method of claim 3 further comprising the steps of:
(a) computing a statistical weight of each said apparent formation property;
(b) weighting each said apparent formation property with said statistical weight thereby forming a corresponding weighted apparent formation property; and (c) combining said weighted apparent formation properties to form said weighted average.
(a) computing a statistical weight of each said apparent formation property;
(b) weighting each said apparent formation property with said statistical weight thereby forming a corresponding weighted apparent formation property; and (c) combining said weighted apparent formation properties to form said weighted average.
5. The method of claim 1, wherein:
step (a) comprises positioning a source of radiation and two of said detectors spaced axially from said source;
step (b) comprises measuring said detector responses from each of said detectors over said time segment;
step (c) comprises sorting said detector responses from each said detector by magnitude into said sorted detector responses;
step (d) comprises computing running integral sums from said sorted detector responses for each said detector;
step (e) comprises for each said detector, fitting said at least one linear segment to said sorted detector responses as a function of time;
step (f) comprises determining an apparent formation property from each of said at least one linear segment for each said detector; and step (g) comprises combining said apparent formation properties to obtain a measure of said formation property compensated for standoff of said two detectors from a wall of said borehole.
step (a) comprises positioning a source of radiation and two of said detectors spaced axially from said source;
step (b) comprises measuring said detector responses from each of said detectors over said time segment;
step (c) comprises sorting said detector responses from each said detector by magnitude into said sorted detector responses;
step (d) comprises computing running integral sums from said sorted detector responses for each said detector;
step (e) comprises for each said detector, fitting said at least one linear segment to said sorted detector responses as a function of time;
step (f) comprises determining an apparent formation property from each of said at least one linear segment for each said detector; and step (g) comprises combining said apparent formation properties to obtain a measure of said formation property compensated for standoff of said two detectors from a wall of said borehole.
6. The method of claim 5 further comprising the additional step of combining slopes of said linear segments to obtain a magnitude of said standoff.
7. The method of claim 5 further comprising the steps of (a) fitting at least two said linear segments for each said detector;
(b) grouping said linear segments in pairs, where each pair represents measurements from a specific azimuthal segment of said borehole;
(c) determining apparent formation properties from each linear segment in each said pair thereby obtaining a pair of azimuthal apparent formation properties;
and (d) combining said pair of azimuthal apparent formation properties to obtain a measure of an azimuthal formation property which is compensated for said standoff.
(b) grouping said linear segments in pairs, where each pair represents measurements from a specific azimuthal segment of said borehole;
(c) determining apparent formation properties from each linear segment in each said pair thereby obtaining a pair of azimuthal apparent formation properties;
and (d) combining said pair of azimuthal apparent formation properties to obtain a measure of an azimuthal formation property which is compensated for said standoff.
8. The method of claim 7 comprising the additional step of determining a magnitude of said standoff from each said azimuthal segment.
9. A method for measuring density of a formation penetrated by a borehole, the method comprising the steps of:
(a) providing a tool which is conveyable along said borehole by a drill string;
(b) positioning within said tool a source of radiation and two radiation detectors spaced axially from said source;
(b) measuring a plurality of detector responses from each of said detectors over a time segment;
(c) sorting said detector responses y magnitude from each said detector into sorted detector responses;
(d) for each said detector fitting at least one linear segment to said sorted detector responses as a function of time;
(e) determining an apparent formation density from said at least one linear segment for each said detector; and (f) combining said apparent formation densities to obtain a measure of said formation density compensated for standoff of said two detectors from a wall of said borehole.
(a) providing a tool which is conveyable along said borehole by a drill string;
(b) positioning within said tool a source of radiation and two radiation detectors spaced axially from said source;
(b) measuring a plurality of detector responses from each of said detectors over a time segment;
(c) sorting said detector responses y magnitude from each said detector into sorted detector responses;
(d) for each said detector fitting at least one linear segment to said sorted detector responses as a function of time;
(e) determining an apparent formation density from said at least one linear segment for each said detector; and (f) combining said apparent formation densities to obtain a measure of said formation density compensated for standoff of said two detectors from a wall of said borehole.
10. The method according to claim 9, further comprising:
computing running integral sums from said sorted detector responses for each said detector;
computing running integral sums from said sorted detector responses for each said detector;
11. The method of claim 9 wherein said radiation source emits gamma radiation and said detectors are responsive to gamma radiation.
12. The method of claim 9 wherein said apparent formation densities are combined using a spine and rib method.
13. The method of claim 9 further comprising combining slopes of said linear segments to obtain a magnitude of said standoff.
14. The method of claim 9 further comprising the steps of:
(a) fitting at least two said linear segments for each said detector;
(b) grouping said linear segments in pairs, wherein each pair represents measurements from a specific azimuthal segment of said borehole;
(c) determining apparent formation density from each linear segment in each said pair thereby obtaining a pair of azimuthal apparent formation densities; and (d) combining said pair of azimuthal apparent formation densities to obtain a measure of an azimuthal formation density which is compensated for said standoff.
(a) fitting at least two said linear segments for each said detector;
(b) grouping said linear segments in pairs, wherein each pair represents measurements from a specific azimuthal segment of said borehole;
(c) determining apparent formation density from each linear segment in each said pair thereby obtaining a pair of azimuthal apparent formation densities; and (d) combining said pair of azimuthal apparent formation densities to obtain a measure of an azimuthal formation density which is compensated for said standoff.
15. The method of claim 14 further comprising the steps of:
(a) computing a statistical weight of each said azimuthal apparent formation density;
(b) weighting each said azimuthal apparent formation density with said statistical weight thereby forming a weighted azimuthal apparent formation density; and (c) combining said weighted azimuthal apparent formation densities to form said formation density compensated for standoff.
(a) computing a statistical weight of each said azimuthal apparent formation density;
(b) weighting each said azimuthal apparent formation density with said statistical weight thereby forming a weighted azimuthal apparent formation density; and (c) combining said weighted azimuthal apparent formation densities to form said formation density compensated for standoff.
16. The method of claim 14 comprising the additional step of determining a magnitude of said standoff for each said azimuthal segment.
17. The method of claim 16 comprising the additional step of mapping a shape of said borehole using said standoff measurement for each segment.
18. An apparatus for determining a property of earth formation penetrated by a borehole, comprising:
(a) at least one detector within said borehole; and (b) computing means for (i) sorting by magnitude a plurality of detector responses from said at least one detector which are measured over a time segment, (ii) fitting at least one linear segment to said running integral sums as a function of time, and (iii) determining said formation property from at least one linear segment.
(a) at least one detector within said borehole; and (b) computing means for (i) sorting by magnitude a plurality of detector responses from said at least one detector which are measured over a time segment, (ii) fitting at least one linear segment to said running integral sums as a function of time, and (iii) determining said formation property from at least one linear segment.
19. The apparatus of claim 18, further comprising computing means for computing running integral sums from said sorted detector responses.
20. The apparatus of claim 18 further comprising computing means for:
(a) obtaining at least two linear segments;
(b) determining an apparent formation property from each of said linear segments; and (c) forming a weighted average of said apparent properties to determine said formation property.
(a) obtaining at least two linear segments;
(b) determining an apparent formation property from each of said linear segments; and (c) forming a weighted average of said apparent properties to determine said formation property.
21. The apparatus of claim 20 further comprising computing means for:
(a) determining a statistical weight of each said apparent formation property;
(b) weighting each said apparent formation property with said statistical weight thereby forming a weighted apparent formation parameter; and (c) combining said weighted apparent formation property to form said weighted average.
(a) determining a statistical weight of each said apparent formation property;
(b) weighting each said apparent formation property with said statistical weight thereby forming a weighted apparent formation parameter; and (c) combining said weighted apparent formation property to form said weighted average.
22. The apparatus of claim 18 further comprising:
(a) a tool which is conveyable within said borehole and which comprises a source of radiation and two of said detectors spaced axially from said source; and (b) computing means for:
(i) collecting said detector responses from each of said detectors over said time segment and sorting said detector responses from each said detector by magnitude;
(ii) computing a running integral sum from said sorted detector responses for each said detector, (iii) fitting for each said detector said at least one linear segment to said sorted detector responses as a function of time, (iv) determining an apparent formation property from each said at least one linear segment for each said detector; and (v) combining said apparent formation properties to obtain a measure of said formation property compensated for standoff of said two detectors from a wall of said borehole.
(a) a tool which is conveyable within said borehole and which comprises a source of radiation and two of said detectors spaced axially from said source; and (b) computing means for:
(i) collecting said detector responses from each of said detectors over said time segment and sorting said detector responses from each said detector by magnitude;
(ii) computing a running integral sum from said sorted detector responses for each said detector, (iii) fitting for each said detector said at least one linear segment to said sorted detector responses as a function of time, (iv) determining an apparent formation property from each said at least one linear segment for each said detector; and (v) combining said apparent formation properties to obtain a measure of said formation property compensated for standoff of said two detectors from a wall of said borehole.
23. The apparatus of claim 22 comprising computing means for combining slopes of said linear segments to obtain a magnitude of said standoff.
24. The apparatus of claim 22 further comprising computing means for:
(a) fitting at least two said linear segments for each said detector;
(b) grouping said linear segments in pairs, wherein each pair represents measurements from a specific azimuthal segment of said borehole;
(c) determining apparent formation properties from each said linear segment in each said pair thereby obtaining a pair of azimuthal apparent formation properties; and (d) combining said pair of azimuthal apparent formation properties to obtain a measure of an azimuthal formation property which is compensated for said standoff.
(a) fitting at least two said linear segments for each said detector;
(b) grouping said linear segments in pairs, wherein each pair represents measurements from a specific azimuthal segment of said borehole;
(c) determining apparent formation properties from each said linear segment in each said pair thereby obtaining a pair of azimuthal apparent formation properties; and (d) combining said pair of azimuthal apparent formation properties to obtain a measure of an azimuthal formation property which is compensated for said standoff.
25. The apparatus of claim 22 further comprising computing means for determining a magnitude of said standoff corresponding to each said azimuthal formation property.
26. A method for measuring formation density of a plurality of azimuthal segments of a formation penetrated by a borehole, the method comprising the steps of:
(a) defining said plurality of azimuthal segments;
(b) providing a tool which is conveyable along a borehole;
(c) positioning within said tool a source of radiation and two radiation detectors spaced axially from said source;
(d) measuring a plurality of detector responses from each of said detectors over a time segment;
(e) sorting said detector responses from each of said detectors according to azimuthal segment in which they are measured thereby forming segment bins of data;
(f) sorting said detector responses from each of said detectors and from each said segment bin by magnitude;
(g) computing running integral sums from said sorted detector responses for each said detector and each said segment bin;
(h) for each said segment bin and for each said detector, fitting said at least one linear segment to said running integral sums as a function of time;
(i) determining an apparent segment formation density from said at least one linear segment for each said detector and each said azimuthal segment; and (j) combining said apparent segment formation densities for each said azimuthal segment to obtain a measure of segment formation density for each said azimuthal segment, wherein said measures of segment formation density are compensated for standoff of said two detectors from a wall of said borehole.
(a) defining said plurality of azimuthal segments;
(b) providing a tool which is conveyable along a borehole;
(c) positioning within said tool a source of radiation and two radiation detectors spaced axially from said source;
(d) measuring a plurality of detector responses from each of said detectors over a time segment;
(e) sorting said detector responses from each of said detectors according to azimuthal segment in which they are measured thereby forming segment bins of data;
(f) sorting said detector responses from each of said detectors and from each said segment bin by magnitude;
(g) computing running integral sums from said sorted detector responses for each said detector and each said segment bin;
(h) for each said segment bin and for each said detector, fitting said at least one linear segment to said running integral sums as a function of time;
(i) determining an apparent segment formation density from said at least one linear segment for each said detector and each said azimuthal segment; and (j) combining said apparent segment formation densities for each said azimuthal segment to obtain a measure of segment formation density for each said azimuthal segment, wherein said measures of segment formation density are compensated for standoff of said two detectors from a wall of said borehole.
27. The method of claim 26 wherein said radiation source emits gamma radiation and said detectors are responsive to gamma radiation.
28. The method of claim 26 wherein said apparent segment formation densities are combined using a spine and rib method.
29. The method of claim 26 wherein said slopes of said linear segments are combined to obtain a magnitude of said standoff for that azimuthal segment.
30. The method of claim 26 further comprising the steps of:
(a) fitting at least two said linear segments for each said detector and each said azimuthal segment;
(b) grouping said at least two linear segments in pairs, where each said pair represents measurements from a specific azimuthal subsegment within each said azimuthal segment;
(c) determining at least two apparent azimuthal subsegment formation densities from each linear segment in each said pair thereby obtaining at least two pairs of apparent azimuthal subsegment apparent formation densities for each said azimuthal segment;
(d) combining each said pair of apparent azimuthal subsegment formation densities to obtain at least two standoff compensated measures of said azimuthal subsegment formation density within each said azimuthal segment; and (e) combining said at least two azimuthal subsegment formation densities within said azimuthal segment to obtain said formation density for that azimuthal segment.
(a) fitting at least two said linear segments for each said detector and each said azimuthal segment;
(b) grouping said at least two linear segments in pairs, where each said pair represents measurements from a specific azimuthal subsegment within each said azimuthal segment;
(c) determining at least two apparent azimuthal subsegment formation densities from each linear segment in each said pair thereby obtaining at least two pairs of apparent azimuthal subsegment apparent formation densities for each said azimuthal segment;
(d) combining each said pair of apparent azimuthal subsegment formation densities to obtain at least two standoff compensated measures of said azimuthal subsegment formation density within each said azimuthal segment; and (e) combining said at least two azimuthal subsegment formation densities within said azimuthal segment to obtain said formation density for that azimuthal segment.
31. The method of claim 30 further comprising the steps of:
(a) computing a statistical weight of each said apparent azimuthal subsegment apparent formation density;
(b) weighting each said apparent azimuthal subsegment formation density with said statistical weight thereby forming a weighted azimuthal subsegment apparent formation density; and (c) combining said weighted azimuthal subsegment apparent formation densities to form said formation density for each said azimuthal segment.
(a) computing a statistical weight of each said apparent azimuthal subsegment apparent formation density;
(b) weighting each said apparent azimuthal subsegment formation density with said statistical weight thereby forming a weighted azimuthal subsegment apparent formation density; and (c) combining said weighted azimuthal subsegment apparent formation densities to form said formation density for each said azimuthal segment.
32. The method of claim 31 comprising the additional step of determining an average magnitude of said standoff for each said azimuthal segment.
33. The method of claim 32 comprising the additional step of mapping the shape of said borehole using said average magnitude for each said azimuthal segment.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/579,971 US6566649B1 (en) | 2000-05-26 | 2000-05-26 | Standoff compensation for nuclear measurements |
| GB0111643A GB2369429B (en) | 2000-05-26 | 2001-05-14 | Standoff compensation for nuclear measurements |
| NO20012574A NO333890B1 (en) | 2000-05-26 | 2001-05-25 | Distance compensation for core tools when logging boreholes |
| CA002349763A CA2349763C (en) | 2000-05-26 | 2001-06-06 | Standoff compensation for nuclear measurements |
| CA2381107A CA2381107C (en) | 2001-05-08 | 2002-04-09 | Standoff compensation for nuclear measurements |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/579,971 US6566649B1 (en) | 2000-05-26 | 2000-05-26 | Standoff compensation for nuclear measurements |
| CA002349763A CA2349763C (en) | 2000-05-26 | 2001-06-06 | Standoff compensation for nuclear measurements |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2349763A1 true CA2349763A1 (en) | 2002-12-06 |
| CA2349763C CA2349763C (en) | 2009-12-29 |
Family
ID=25682606
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002349763A Expired - Lifetime CA2349763C (en) | 2000-05-26 | 2001-06-06 | Standoff compensation for nuclear measurements |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US6566649B1 (en) |
| CA (1) | CA2349763C (en) |
| GB (1) | GB2369429B (en) |
| NO (1) | NO333890B1 (en) |
Families Citing this family (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6662870B1 (en) * | 2001-01-30 | 2003-12-16 | Cdx Gas, L.L.C. | Method and system for accessing subterranean deposits from a limited surface area |
| US8376052B2 (en) | 1998-11-20 | 2013-02-19 | Vitruvian Exploration, Llc | Method and system for surface production of gas from a subterranean zone |
| US8297377B2 (en) | 1998-11-20 | 2012-10-30 | Vitruvian Exploration, Llc | Method and system for accessing subterranean deposits from the surface and tools therefor |
| US6708764B2 (en) * | 2002-07-12 | 2004-03-23 | Cdx Gas, L.L.C. | Undulating well bore |
| US6280000B1 (en) | 1998-11-20 | 2001-08-28 | Joseph A. Zupanick | Method for production of gas from a coal seam using intersecting well bores |
| US7025154B2 (en) | 1998-11-20 | 2006-04-11 | Cdx Gas, Llc | Method and system for circulating fluid in a well system |
| US7048049B2 (en) * | 2001-10-30 | 2006-05-23 | Cdx Gas, Llc | Slant entry well system and method |
| US6590202B2 (en) * | 2000-05-26 | 2003-07-08 | Precision Drilling Technology Services Group Inc. | Standoff compensation for nuclear measurements |
| US6619395B2 (en) * | 2001-10-02 | 2003-09-16 | Halliburton Energy Services, Inc. | Methods for determining characteristics of earth formations |
| US6907944B2 (en) * | 2002-05-22 | 2005-06-21 | Baker Hughes Incorporated | Apparatus and method for minimizing wear and wear related measurement error in a logging-while-drilling tool |
| US6991048B2 (en) * | 2002-07-12 | 2006-01-31 | Cdx Gas, Llc | Wellbore plug system and method |
| US6725922B2 (en) * | 2002-07-12 | 2004-04-27 | Cdx Gas, Llc | Ramping well bores |
| US6991047B2 (en) * | 2002-07-12 | 2006-01-31 | Cdx Gas, Llc | Wellbore sealing system and method |
| US8333245B2 (en) * | 2002-09-17 | 2012-12-18 | Vitruvian Exploration, Llc | Accelerated production of gas from a subterranean zone |
| US7253402B2 (en) * | 2003-09-30 | 2007-08-07 | Baker Hughes Incorporated | Apparatus and method for determining thermal neutron capture cross section of a subsurface formation from a borehole using multiple detectors |
| US20050075730A1 (en) | 2003-10-06 | 2005-04-07 | Myers Keith E. | Minimally invasive valve replacement system |
| US20070005251A1 (en) * | 2005-06-22 | 2007-01-04 | Baker Hughes Incorporated | Density log without a nuclear source |
| WO2008123853A1 (en) * | 2007-04-10 | 2008-10-16 | Halliburton Energy Services, Inc. | Combining lwd measurements from different azimuths |
| US10302811B2 (en) * | 2008-08-21 | 2019-05-28 | Weatherford Technology Holdings, Llc | Data reduction of images measured in a borehole |
| US9031790B2 (en) * | 2010-03-23 | 2015-05-12 | Schlumberger Technology Corporation | System and method for correction of borehole effects in a neutron porosity measurement |
| US9012836B2 (en) * | 2011-10-27 | 2015-04-21 | Weatherford Technology Holdings, Llc | Neutron logging tool with multiple detectors |
| US9753177B2 (en) * | 2013-11-12 | 2017-09-05 | Baker Hughes Incorporated | Standoff specific corrections for density logging |
| CN108756855A (en) * | 2018-04-26 | 2018-11-06 | 中国石油天然气集团有限公司 | One kind is with brill gamma instrument environments bearing calibration placed in the middle |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4423323A (en) * | 1981-09-09 | 1983-12-27 | Schlumberger Technology Corporation | Neutron logging method and apparatus for determining a formation characteristic free of environmental effects |
| US4972082A (en) | 1989-03-16 | 1990-11-20 | Schlumberger Technology Corporation | Methods and apparatus for epithermal neutron logging |
| US5196698A (en) | 1991-11-01 | 1993-03-23 | Baker Hughes Corporation | Method and apparatus for nuclear logging using lithium detector assemblies |
| US6350986B1 (en) | 1999-02-23 | 2002-02-26 | Schlumberger Technology Corporation | Analysis of downhole OBM-contaminated formation fluid |
-
2000
- 2000-05-26 US US09/579,971 patent/US6566649B1/en not_active Expired - Lifetime
-
2001
- 2001-05-14 GB GB0111643A patent/GB2369429B/en not_active Expired - Lifetime
- 2001-05-25 NO NO20012574A patent/NO333890B1/en not_active IP Right Cessation
- 2001-06-06 CA CA002349763A patent/CA2349763C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US6566649B1 (en) | 2003-05-20 |
| NO20012574D0 (en) | 2001-05-25 |
| NO333890B1 (en) | 2013-10-14 |
| NO20012574L (en) | 2001-11-27 |
| GB2369429A (en) | 2002-05-29 |
| CA2349763C (en) | 2009-12-29 |
| GB0111643D0 (en) | 2001-07-04 |
| GB2369429B (en) | 2004-06-30 |
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| EEER | Examination request | ||
| MKEX | Expiry |
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| MKEX | Expiry |
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