Methods and Means for Simultaneous Casing Integrity Evaluation and Cement Inspection in a Multiple-Casing Wellbore Environment
An x-ray based cement evaluation tool for measurement of the density of material volumes within single, dual and multiple-casing wellbore environments is provided, wherein the tool uses x-rays to illuminate the formation surrounding a borehole, and a plurality of detectors are used to directly measure the density of the cement annuli and any variations in density within The tool uses x-rays to illuminate the casing surrounding a borehole and a plurality of multi-pixel imaging detectors directly measure the thickness of the casing The tool includes an internal length having a sonde section, wherein the sonde section further includes an x-ray source; a radiation shield for radiation measuring detectors; sonde-dependent electronics; and a plurality of tool logic electronics and PSUs. Other systems and subsystems appropriate for carrying out the foregoing are also disclosed, as are a plurality of example methods of use therefor.
1 . An x-ray based cement evaluation tool for measurement of the density of material volumes, wherein the tool uses x-rays to illuminate a formation surrounding a borehole and a plurality of detectors are used to measure the density of the cement annuli and variations in density within, said tool further comprising:
an internal length comprising a sonde section, wherein said sonde section further comprises an x-ray source;
a radiation shield for radiation measuring detectors;
sonde-dependent electronics;
and a plurality of tool logic electronics and PSUs.
2 . The tool of claim 1 , further comprising a detector that is used to measure casing standoff such that other detector responses are compensated for tool stand-off and centralization.
3 . The tool of claim 1 , wherein said shield further comprises tungsten.
4 . The tool of claim 1 , wherein the tool is configured so as to permit through-wiring.
5 . The tool of claim 1 , wherein a plurality of reference detectors is used to monitor the azimuthal output of the x-ray source.
6 . The tool of claim 1 , wherein the shortest-axial offset imaging detector array is configured to distribute incoming photons into energy classifications such that photoelectric measurements may be made.
7 . The tool of claim 1 , wherein the x-ray source energy is capable of being modulated to modify the optimum-detector axial offset in order to assist with the creation of response sensitivity functions.
8 . The tool of claim 1 , wherein the tool is combinable with other measurement tools comprising one or more of neutron-porosity, natural gamma and array induction tools.
9 . The tool of claim 1 , wherein an azimuthally segmented acoustic measurement is integrated into the tool.
10 . The tool of claim 1 , wherein the tool determines the position, distribution and volume of fractures, either natural or artificial, within the formation surrounding the cased wellbore.
11 . The tool of claim 1 , wherein the tool is integrated into a logging-while-drilling assembly.
12 . The tool of claim 1 , wherein the tool is powered by mud-turbine generators.
13 . The tool of claim 1 , wherein the tool is powered by batteries.
14 . The tool of claim 1 , wherein the tool is configured so as to permit through-wiring.
15 . The tool of claim 1 , wherein a plurality of reference detectors is used to monitor the output of the x-ray source.
16 . The tool of claim 1 , wherein the shortest-axial offset detector is configured to distribute incoming photons into energy classifications such that photoelectric measurements may be made.
17 . The tool of claim 1 , wherein the x-ray source energies are modulated to modify the optimum-detector axial offset in order to assist with the creation of response sensitivity functions.
18 . The tool of claim 1 , wherein the tool is combinable with other measurement tools comprising one or more of neutron-porosity, natural gamma and array induction tools.
19 . The tool of claim 1 , wherein azimuthally segmented acoustic measurements are integrated into the tool.
20 . The tool of claim 1 , wherein the tool determines the position, distribution and volume of fractures, either natural or artificial, within the formation surrounding the cased wellbore.
21 . The method of x-ray based cement evaluation for measuring the density of material volumes within single, dual and multiple-casing wellbore environment, wherein said method comprises:
illuminating the formation surrounding a borehole using x-rays;
using a plurality of detectors to measure the density of the cement annuli and any variations in density within; and
illuminating the casing surrounding a borehole using x-rays and then using a plurality of multi-pixel imaging detectors to measure the thickness of the casing.
22 . The method of claim 21 , further comprising: measuring casing standoff such that other detector responses can be compensated for tool stand-off and centralization.
23 . The method of claim 21 , further comprising using a plurality of reference detectors to monitor the azimuthal output of the x-ray source.
24 . The method of claim 21 , further comprising: configuring the shortest-axial offset imaging detector array to distribute incoming photons into energy classifications such that photoelectric measurements may be made.
25 . The method of claim 21 , further comprising modulating the x-ray source energy source to modify the optimum-detector axial offset to aid the creation of response sensitivity functions.
26 . The method of claim 21 , further comprising combining the tool with other measurement tools comprising one or more of neutron-porosity, natural gamma and array induction tools.
27 . The method of claim 21 , further comprising integrating an azimuthally segmented acoustic measurement into the tool.
28 . The method of claim 21 , further comprising determining the position, distribution and volume of fractures, either natural or artificial, within the formation surrounding the cased wellbore.
29 . The method of claim 21 , further comprising using a plurality of reference detectors to monitor the output of the x-ray source.
30 . The method of claim 21 , further comprising configuring the shortest-axial offset detector to distribute incoming photons into energy classifications such that photoelectric measurements may be made.
31 . The method of claim 21 , further comprising modulating the x-ray source energies so as to modify the optimum-detector axial offset in order to aid the creation of response sensitivity functions.
32 . The method of claim 21 , further comprising determining the position, distribution and volume of fractures, either natural or artificial, within the formation surrounding the cased wellbore.