Logging-While-Drilling Resistivity-at-the-Bit...
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Description Applications Schematic illustration of the Resistivity- at-the-Bit tool (LWD-RAB). Specifications ODP Logging Services, Lamont-Doherty Earth Observatory, Rt. 9W, Palisades, NY 10964 Logging-While-Drilling Resistivity-at-the-Bit Tool ♦ Detection of resistivity heterogeneity via azimuthal resistivity images ♦ Lithology estimation ♦ Instantaneous detection of casing and coring points ♦ Accurate resistivity when mud is salty or formation resistivity is high ♦ Detection of early invasion of borehole fluids into the formation The Resistivity-at-the-Bit tool (LWD-RAB) makes azimuthal resistivity and gamma ray measurements while drilling. Using an azimuthal positioning system, measurements are acquired around the borehole to create a high resolution, 360-degree resistivity image of the drilled hole. The RAB tool may be connected directly behind the bit or further back in the bottom hole assembly. It may be run with other LWD tools such as the ADN, ISONIC or NMR. Typically, the RAB data are stored in memory within the tool and retrieved at the end of the bit run. As an option, the data may be transmitted to a surface acquisition system if a Measurement-While-Drilling (MWD) power pulse tool is run in conjunction with the RAB. Assembly of the RAB tool aboard the JOIDES Resolution. Optional uphole connector Batteries Upper sensor Middle sensor, containing focused ring electrode Azimuthal gamma ray Field-replaceable stabilizer Lower sensor Float valve bore Rbit electrode : t h g i e w l o o T m b l 0 0 2 1 : h t g n e l l o o T ) m 8 0 . 3 ( t f 1 . 0 1 : e g n a r e r u t a r e p m e T ) C ° 0 5 1 o t ° 5 2 - ( F ° 0 0 3 o t ° 3 1 - : r e t e m a i d e d i s t u o l a n i m o n r a l l o c l l i r D . n i 5 7 . 6 : ) l a h t u m i z a ( r e t e m a i d e d i s t u o . x a m r a l l o c l l i r D . n i 5 2 1 . 8 : r e w o P ) s r h + 0 0 2 ( k c a p y r e t t a b m u i h t i L : e u q r o t m u m i x a m d e d n e m m o c e R f b l - t f 0 0 0 , 6 1 : y c a r u c c a t n e m e r u s a e m y t i v i t s i s e R e g n a R e d o r t c e l e d e s u c o f & t i B l a h t u m i z A 1 - 2 . 0 % 0 2 - / + % 0 2 - / + 0 0 0 1 - 2 % 5 - / + % 5 - / + 0 0 0 2 - 0 0 0 1 % 0 1 - / + % 0 2 - / + 0 0 0 , 0 2 - 0 0 0 2 % 0 2 - / + - - - : s n o i t a c i f i c e p s y a r a m m a G : e g n a R s t i n u I P A 0 5 2 - 0 : y t i l i b a t a e p e r l a c i t s i t a t s a m g i s e n O r h / t f 0 0 1 t a % 3 < ) g n i g a r e v a l e v e l - 3 , n o i t a m r o f I P A - 0 1 ( r h / t f 0 5 t a % 2 < : e t a r w o l f m u m i x a M n i m / l a g 0 0 8 : e r u s s e r p g n i t a r e p o m u m i x a M i s p 0 0 0 , 8 1 : t i b n o t h g i e w m u m i x a M L / 0 0 0 , 0 0 0 , 4 7 = F 2 s i L e r e h w ( f b l ) t e e f n i s r e z i l i b a t s n e e w t e b e c n a t s i d : d a o l g n i r r a j m u m i x a M f b l 0 0 0 , 0 3 3
Transcript of Logging-While-Drilling Resistivity-at-the-Bit...
Description
Applications
Schematic illustration of the Resistivity-at-the-Bit tool (LWD-RAB).
Specifications
ODP Logging Services, Lamont-Doherty Earth Observatory, Rt. 9W, Palisades, NY 10964
Logging-While-DrillingResistivity-at-the-Bit Tool
♦ Detection of resistivity heterogeneity viaazimuthal resistivity images
♦ Lithology estimation♦ Instantaneous detection of casing and coring
points♦ Accurate resistivity when mud is salty or
formation resistivity is high♦ Detection of early invasion of borehole fluids
into the formation
The Resistivity-at-the-Bit tool (LWD-RAB) makesazimuthal resistivity and gamma ray measurements whiledrilling. Using an azimuthal positioning system,measurements are acquired around the borehole to create ahigh resolution, 360-degree resistivity image of the drilledhole. The RAB tool may be connected directly behind thebit or further back in the bottom hole assembly. It may berun with other LWD tools such as the ADN, ISONIC orNMR. Typically, the RAB data are stored in memory withinthe tool and retrieved at the end of the bit run. As an option,the data may be transmitted to a surface acquisition systemif a Measurement-While-Drilling (MWD) power pulse toolis run in conjunction with the RAB.
Assembly of the RAB tool aboardthe JOIDES Resolution.
Optional uphole connector
Batteries
Upper sensor
Middle sensor, containing focused ring electrode
Azimuthal gamma ray
Field-replaceable stabilizer
Lower sensor
Float valve boreRbit electrode
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