A detector that detects properties of geological formation includes a first volume and a second volume each comprising Helium-3 gas. The detector includes a gas electron multiplier having a mesh plate disposed between the first volume and the second volume. The mesh plate creates an electric field that multiplies electrons of the second volume based on epithermal neutrons in the second volume. The detector includes at least one anode configured to receive electrons based on thermal neutrons in the first volume and epithermal neutrons in the second volume.

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 method for determining a petrophysical property of a formation includes detecting radiation events resulting from imparting neutrons into the formation at an energy level of at least 1 MeV. The petrophysical property is determined from an elastic scattering cross section of the formation. The elastic scattering cross section is related to a number of detected radiation events.

Methods and systems for measuring neutron sigma of downhole reservoir as a function of time for a predetermined testing volume are disclosed. The methods and systems of the present invention analyze the testing volume while maintaining the formation in the testing volume in an unchanged and undamaged state and while dynamically flowing fluids in and out of the testing volume. The systems and methods of the present invention are especially important in determining petrophysical information about the reservoir as well as the in-situ effect of substances on enhanced oil recovery.

A detector that detects properties of geological formation includes a first volume and a second volume each comprising Helium-3 gas. The detector includes a gas electron multiplier having a mesh plate disposed between the first volume and the second volume. The mesh plate creates an electric field that multiplies electrons of the second volume based on epithermal neutrons in the second volume. The detector includes at least one anode configured to receive electrons based on thermal neutrons in the first volume and epithermal neutrons in the second volume.

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.

Methods and devices for evaluating earth formations. Methods include making a plurality of radiation measurements with a GR detector disposed on a carrier in the borehole and a second GR detector disposed on the carrier by positioning the first GR detector and the second GR detector in the borehole at each borehole depth such that the first GR detector is radially offset from the second GR detector with respect to the longitudinal axis of the borehole; making an estimate of a concentration of at least one chemical element in the formation for each borehole depth for each of the first GR detector and the second GR detector from the plurality of measurements; and estimating an actual concentration of the at least one chemical element using the estimates of the concentration for the first GR detector and the estimates of the concentration for the second GR detector for each borehole depth.

A neutron detection apparatus, method, and system includes a scintillation device that emits photons in response to received neutron energy incident on the device. A gamma radiation source, coupled to the scintillation device and configured to emit a reference energy, is also detected by the scintillation device. The reference energy has a different energy than the neutron radiation. A light sensor is coupled to the scintillation device. The light sensor receives and converts the emitted photons into an electrical signal comprising an indication of both the reference energy and the received neutron energy.

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).

Systems, methods, and devices for determining 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, neutron detector, two gamma-ray detectors, and data processing circuitry. Neutron generator may emit neutrons into a formation, causing a fast neutron cloud to form. Neutron detector may detect a count of neutrons representing the extent of the neutron cloud. 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, 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.