E - Fixed Constructions – 21 – B
Patent
E - Fixed Constructions
21
B
E21B 49/00 (2006.01) G01V 5/10 (2006.01) E21B 41/00 (2006.01)
Patent
CA 2074594
A borehole logging tool is lowered into a borehole traversing a subsurface formation and a neutron detector measures the die-away of nuclear radiation in the formation. A model of the die-away of nuclear radiation is produced using exponential terms varying as the sum of borehole, formation and thermal neutron background components. Exponentially weighted moments of both the die-away measurements and die-away model are determined and equated. The equated moments are solved for the ratio of the borehole to formation amplitude components of the measurements. The formation decay constant is determined from at least the formation and thermal neutron background terms of the weighted measurement aril model moments. An epithermal neutron lifetime is determined from the formation decay constant. This epithermal neutron lifetime and the amplitude ratio are used by a trained neural network to determine a lifetime correction and an apparent standoff. A standoff corrected lifetime is determined from the epithermal neutron lifetime and the lifetime correction. A porosity log of the formation is produced which is corrected for detector standoff from the borehole wall as a function of the standoff corrected epithermal neutron lifetime calibrated in borehole models of known porosities.
Allen Linus Scott
Leland Frank Paynter
Lyle W. D. Jr.
Stromswold David Charles
Exxonmobil Oil Corporation
Gowling Lafleur Henderson Llp
Mobil Oil Corporation
LandOfFree
Method and apparatus for producing a porosity log of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for producing a porosity log of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for producing a porosity log of a... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1753030