Logging-while-drilling tool incorporating electronic radiation generator and method of using same

Abstract

Logging-while-drilling tools incorporating an electronic radiation generator, such as an electronic X-ray generator, and a method for using the same are provided. One example of such a logging-while-drilling tool may include a circumferential drill collar, a chassis disposed radially interior to the drill collar, and an electronic X-ray generator and an X-ray detector disposed within the chassis. The electronic X-ray generator may emit X-rays out of the logging-while-drilling tool into a subterranean formation. The X-ray detector may detect X-rays that return to the logging-while-drilling tool after scattering in the subterranean formation, which may be used to determine a density and/or a lithology of the subterranean formation.

What is claimed is: 
     
         1 . A logging-while-drilling tool comprising:
 a circumferential drill collar having a space in the drill collar; and   a pressure housing disposed in the space, wherein the pressure housing includes an electronic X-ray generator configured to emit X-rays out of the logging-while-drilling tool and into a subterranean formation and an X-ray detector configured to detect X-rays that return to the logging-while-drilling tool after scattering in the subterranean formation.   
     
     
         2 . The logging-while-drilling tool of  claim 1 , wherein the space is drilled in the drill collar. 
     
     
         3 . The logging-while-drilling tool of  claim 1 , wherein the space is disposed in the drill collar at a non-zero angle to an axis of the logging-while-drilling tool. 
     
     
         4 . The logging-while-drilling tool of  claim 1 , wherein the space is disposed in the drill collar substantially in parallel to an axis of the logging-while-drilling tool. 
     
     
         5 . The logging-while-drilling tool of  claim 1 , further comprising an X-ray monitor configured to monitor the X-rays emitted by the electronic X-ray generator. 
     
     
         6 . The logging-while-drilling tool of  claim 1 , further comprising a plurality of X-ray detectors configured to detect X-rays that return to the logging-while-drilling tool after scattering in the subterranean formation at different azimuthal directions. 
     
     
         7 . The logging-while drilling tool of  claim 1 , wherein the electronic X-ray generator is collimated to emit X-rays out of the logging-while-drilling tool at an angle. 
     
     
         8 . The logging-while-drilling tool of  claim 1 , wherein the electronic X-ray generator comprises a grounded-target X-ray generator, a bipolar X-ray generator, or a grounded-electron-source X-ray generator. 
     
     
         9 . The logging-while-drilling tool of  claim 1 , wherein the drill collar comprises a first X-ray-permissive window configured to permit X-rays emitted by the X-ray generator to exit the drill collar and a second X-ray-permissive window configured to permit some X-rays to enter the drill collar to be detected by the X-ray detector. 
     
     
         10 . The logging-while-drilling tool of  claim 9 , wherein the first and second X-ray-permissive windows comprise titanium or beryllium, or a combination thereof. 
     
     
         11 . A logging-while-drilling tool comprising:
 a circumferential drill collar, wherein the drill collar comprises an integrated stabilizer disposed at a non-zero angle to an axis of the logging-while-drilling tool; and   a pressure housing disposed in the drill collar beneath the integrated stabilizer along the non-zero angle to the axis of the logging-while-drilling tool, wherein the pressure housing includes an electronic X-ray generator configured to emit X-rays out of the logging-while-drilling tool from at a first axial location at a first circumferential location aligned to the axis of the logging-while-drilling tool and into a subterranean formation and an X-ray detector configured to detect X-rays that return to a second axial location at the first circumferential location of the logging-while-drilling tool after scattering in the subterranean formation.   
     
     
         12 . The logging-while-drilling tool of  claim 11 , wherein the electronic X-ray generator and the X-ray detector are disposed substantially in parallel with the axis of the logging-while-drilling tool. 
     
     
         13 . The logging-while-drilling tool of  claim 11 , wherein the drill collar comprises a first X-ray-permissive window configured to permit X-rays emitted by the X-ray generator to exit the drill collar and a second X-ray-permissive window configured to permit some X-rays to enter the drill collar to be detected by the X-ray detector. 
     
     
         14 . The logging-while-drilling tool of  claim 13 , wherein the first X-ray-permissive window and the second X-ray-permissive window are substantially in parallel with the axis of the logging-while-drilling tool. 
     
     
         15 . The logging-while-drilling tool of  claim 11 , comprising a wear-protective covering disposed over the pressure housing configured to protect the pressure housing from wear. 
     
     
         16 . The logging-while-drilling tool of  claim 11 , further comprising a plurality of X-ray detectors configured to detect X-rays that return to the logging-while-drilling tool after scattering in the subterranean formation at different azimuthal directions. 
     
     
         17 . The logging-while drilling tool of  claim 11 , wherein the electronic X-ray generator is collimated to emit X-rays out of the logging-while-drilling tool at an angle. 
     
     
         18 . The logging-while-drilling tool of  claim 11 , wherein the electronic X-ray generator comprises a grounded-target X-ray generator, a bipolar X-ray generator, or a grounded-electron-source X-ray generator. 
     
     
         19 . A method comprising:
 drilling a borehole into a subterranean formation using a borehole assembly that includes a logging-while-drilling tool;   emitting X-rays using an electronic X-ray generator of the logging-while-drilling tool into the subterranean formation;   detecting X-rays that return to the logging-while-drilling tool after scattering off the subterranean formation using a plurality of X-ray detectors configured to detect X-rays arriving from a respective plurality of azimuthal angles; and   determining, using data processing circuitry, an azimuthal distribution of at least one property of the subterranean formation based at least in part on the detected X-rays.   
     
     
         20 . The method of  claim 19 , wherein the at least one property comprises a density or a lithology, or a combination thereof.