The present disclosure provides a gamma-ray attenuator and a gamma-ray shield for use in gamma-ray spectroscopy. The gamma-ray attenuator is a sleeve comprising a wall, a distal end, and a proximal end. The distal end of the sleeve is closed, and the proximal end of the sleeve forms an opening. A copper insert, a tin insert and a tungsten insert are installed in the sleeve such that the copper insert is adjacent to the distal end and the tungsten insert is closest to the proximal end. The sleeve is comprised of one or more materials that do not substantially attenuate gamma-rays. The open end of the sleeve fits over a tungsten safe that is operable to hold a radionuclide sample. When fitted together, a gamma-ray attenuator and a safe comprise a gamma-ray shield.

An apparatus and method for downhole measurement during operation of a drilling system is disclosed. The apparatus (30) comprises: a first sensor (302) configured to detect a property of a subsurface formation (200); a radiation source (304) configured to, when triggered, emit radiation to excite a part (220) of the formation; a processing unit (308) configured to trigger the radiation source if a change of the property of the formation is detected; a second sensor (306) positioned at a known distance from the radiation source and operably connected to the processing unit, the second sensor is configured to detect said excited part of the formation and is more distant from a drill bit (104) of the drilling system than the radiation source is; the processing unit is further configured to, after the excited part of the formation is detected, calculate a rate of penetration of the drill bit based on the following: a time duration between the radiation source is triggered and the excited part of formation is detected, and the distance between the radiation source and the second sensor.

An apparatus and method for downhole measurement during operation of a drilling system is disclosed. The apparatus (30) comprises: a first sensor (302) configured to detect a property of a subsurface formation (200); a radiation source (304) configured to, when triggered, emit radiation to excite a part (220) of the formation; a processing unit (308) configured to trigger the radiation source if a change of the property of the formation is detected; a second sensor (306) positioned at a known distance from the radiation source and operably connected to the processing unit, the second sensor is configured to detect said excited part of the formation and is more distant from a drill bit (104) of the drilling system than the radiation source is; the processing unit is further configured to, after the excited part of the formation is detected, calculate a rate of penetration of the drill bit based on the following: a time duration between the radiation source is triggered and the excited part of formation is detected, and the distance between the radiation source and the second sensor.

A neutron imaging device employs a neutron source including a sealed enclosure, gamma ray detector(s) spaced from the neutron source, and particle detector(s) disposed in the sealed enclosure of the neutron source. The output of the particle detector(s) can be used to obtain a direction of particles generated by the neutron source and corresponding directions of neutrons generated by the neutron source. Such information can be processed to determine locations in the surrounding borehole environment where the secondary gamma rays are generated and determine data representing formation density at such locations. In one aspect, the gamma ray detector(s) of the neutron imaging device can include at least one scintillation crystal with shielding disposed proximate opposite ends of the scintillation crystal. In another aspect, the particle detector(s) of the neutron imaging device can include a resistive anode encoder having a ceramic substrate and resistive glaze.

The current disclosure is related to a downhole tool that comprises an electronic photon generator and at least one detector. The electronic photon generator comprises a cathode configured to emit electrons, a first target configured to generate photons when struck by the electrons, a second target configured to generate photons when struck by the electrons, and a beam steering device that directs the electrons to a first or second target. The at least one detector is configured to detect at least some of the photons emitted by the first target and at least some of the photons emitted by the second target.

The current disclosure is related to a downhole tool that comprises an electronic photon generator and at least one detector. The electronic photon generator comprises a cathode configured to emit electrons, a first target configured to generate photons when struck by the electrons, a second target configured to generate photons when struck by the electrons, and a beam steering device that directs the electrons to a first or second target. The at least one detector is configured to detect at least some of the photons emitted by the first target and at least some of the photons emitted by the second target.

The present disclosure describes a downhole tool including an electrically operated radiation generator that selectively output radiation to a surrounding environment based at least in part on supply of electrical power; and a control system that determines likelihood of exposing living beings in the surrounding environment to output radiation by determining whether one or more check conditions is met; determine that each of the one or more check conditions is met before instructing the electrically operated radiation generator to output radiation; and instruct the electrically operated radiation generator to cease output of radiation when at least one of the one or more check conditions is no longer met.

The present disclosure describes a downhole tool including an electrically operated radiation generator that selectively output radiation to a surrounding environment based at least in part on supply of electrical power; and a control system that determines likelihood of exposing living beings in the surrounding environment to output radiation by determining whether one or more check conditions is met; determine that each of the one or more check conditions is met before instructing the electrically operated radiation generator to output radiation; and instruct the electrically operated radiation generator to cease output of radiation when at least one of the one or more check conditions is no longer met.

Embodiments provide a method for surveying a hydrocarbon reservoir utilizing a reservoir model. The method includes the step of establishing an ensemble of models reflecting attributes of the hydrocarbon reservoir based on the reservoir model in its present state. The method includes the step of updating the reservoir model by utilizing a volumetric density image of the hydrocarbon reservoir. The volumetric density image can be constructed via muon tomography.

A downhole tool may include a voltage multiplier within a housing. The voltage multiplier may transform input power to the downhole tool from a first voltage to a second voltage higher than the first. The downhole tool may also include multiple shielding rings surrounding at least the voltage multiplier to reduce electric field stresses within the downhole tool. Additionally, the downhole tool may include an insulator located between the shielding rings and the housing.