A wellbore inspection device includes a radiation generation source operable to emit neutrons, and a radiation detector fixed relative to the radiation generation source and operable to detect backscattered neutron radiation from a surrounding environment. The radiation detector includes a plurality of individually addressable detector elements arranged in one or more concentric rings. Respective amounts of backscattered neutron radiation detected by the individually addressable detector elements within a ring is indicative of the azimuthal direction of the detected backscattered neutron radiation, and the respective amount of backscattered neutron radiation detected by the individually addressable detector elements of two or more concentric rings is indicative of an energy level of the backscattered neutron radiation. The inspection device determines whether a potential anomaly is present in or around the wellbore, based at least in part on the respective amounts of backscattered radiation detected by the individually addressable detector elements.

A downhole multi-modality inspection system includes a first imaging device operable to generate first imaging data and a second imaging device operable to generate second imaging data. The first imaging device includes a first source operable to emit energy of a first modality, and a first detector operable to detect returning energy induced by the emitted energy of the first modality. The second imaging device includes a second source operable to emit energy of a second modality, and a second detector operable to detect returning energy induced by the emitted energy of the second modality. The system further includes a processor configured to receive the first imaging data and the second imaging data, and integrate the first imaging data with the second imaging data into an enhanced data stream. The processor correlates the first imaging data and the second imaging data to provide enhanced data for detecting potential wellbore anomalies.

A position determination system and a method for position detection within a wellbore are disclosed. A radioactive tag may be disposed within the wellbore. One or more scintillating optical fibers may be longitudinally disposed along a drill string, wireline, or the like, and run into the wellbore. A detector system is coupled to the optical fiber(s). A scintillating optical fiber emits short, bright flashes of visible light whenever exposed to the gamma radiation. When a scintillating flash is measured, it may be determined that the optical fiber is located within proximity to the radioactive tag. The amplitude of received pulses may be used to estimate where in the optical fiber scintillating events are occurring. By providing a second optical fiber coupled to a scintillating optical fiber, a time delay between received pulses may be used to indicate where along the scintillating optical fiber scintillation events are occurring.

A combining mechanism for borehole logging tool data that employs modality merging to combine the output data of various borehole logging tools to provide a combined result and automated interpretation is provided, said mechanism comprising: at least one mechanism for assigning interpretive values to individual processed data types; at least one mechanism for combining the interpretive value data sets; and, at least one mechanism for providing an interpretation. A method of combining borehole logging tool data that employs modality merging to combine the output data of various borehole logging tools to provide a combined result and automated interpretation is also provided, said method comprising: assigning interpretive values to individual processed data types; combining the interpretive value data sets; and, providing an interpretation.

Methods, systems, and computer program products for correcting cased hole neutron porosity logs provide a residual correction that substantially accounts for potential coupling between casing thickness and other environmental parameters. The residual correction may be used to derive a casing thickness response function that is customized for the particular well under consideration. The customized casing thickness response function may then be used to adjust cased hole neutron porosity logs for the well in a manner that more accurately counts for potential coupling of the effects of casing thickness and other environmental parameters, in contrast to existing solutions that tend to ignore such potential coupling.

Systems, methods, and devices for determining a neutron-gamma density (NGD) measurement of a subterranean formation that is accurate in both liquid- and gas-filled formations are provided. For example, a downhole tool for obtaining such an NGD measurement may include a neutron generator, a neutron detector, two gamma-ray detectors, and data processing circuitry. The neutron generator may emit neutrons into a formation, causing a fast neutron cloud to form. The neutron detector may detect a count of neutrons representing the extent of the neutron cloud. The gamma-ray detectors may detect counts of inelastic gamma-rays caused by neutrons that inelastically scatter off the formation. Since the extent of the fast neutron cloud may vary depending on whether the formation is liquid- or gas-filled, the data processing circuitry may determine the density of the formation based at least in part on the counts of inelastic gamma-rays normalized to the count of neutrons.

Systems and methods for downhole component monitoring including a monitored component doped with a pre-selected neutron absorbent, the monitored component being part of a downhole tool and a neutron monitoring system positioned relative to the monitored component. The neutron monitoring system includes a neutron source positioned at a first location relative to the monitored component and a neutron detector positioned at a second location relative to the monitored component, the neutron detector configured to detect neutrons from the neutron source and count said detected neutrons. A control unit is in communication with the neutron detector and configured to determine a status of the monitored component from the neutron count received from the neutron detector.

A tool can include an X-ray tomography device to evaluate cement in a downhole environment. The X-ray tomography device includes an X-ray beam source configured to transmit an X-ray beam at a first predetermined angle. The beam angle may be set by a capillary device coupled to the X-ray beam source. An energy dispersive, multi-pixel photon detector is configured to count detected backscatter photons received at a second predetermined angle and determine an energy spectrum for the detected photons. A density map of the cement may be generated in response to the number of detected photons. Additional apparatus, systems, and methods are disclosed.

Devices and methods for a rugged semiconductor radiation detector are provided. The semiconductor detector may include a hermetically sealed housing and a semiconductor disposed within the housing that has a first surface and a second surface opposite one another. A first metallization layer may at least partially cover the first surface of the semiconductor and a second metallization layer may at least partially cover the second surface of the semiconductor. The first metallization layer or the second metallization layer, or both, do not extend completely to an edge of the semiconductor, thereby providing a nonconductive buffer zone. This reduces electrical field stresses that occur when a voltage potential is applied between the first metallization layer and the second metallization layer and reduces a likelihood of electrical failure (e.g., due to arcing).

A neutron generator includes a gas control interface and a vacuum chamber coupled to the gas control interface. The neutron generator also includes a target rod disposed within the vacuum chamber and having a longitudinal axis aligned with a central axis of the vacuum chamber, and further including a target disposed on a surface of the target rod facing the getter. The neutron generator also includes a planar ion source adjacent to the gas control interface and disposed between the target and the gas control interface. The planar ion source includes an array grid that is offset from the target and generally perpendicular to the longitudinal axis of the target rod.