Schlumberger Technology Corporation

Halliburton Energy Services, Inc.

Schlumberger Technology Corpoation

Zilu Zhou

Bradley Albert Roscoe

Markus Berheide

Christian Stoller

Weijun Guo

Kenneth Edward Stephenson

James A Grau

Olivier G Philip

Joyce Wong

Felix K Chen

Frederic Gicquel

Lesley Allison Fessler

James Martin Price

Christopher Harrison

Joel Lee Groves

Martin G Luling

Douglas W Grant

Richard G Saenger

Gary W Corris

Joshua Wayne Gibson

Jimmy W Anders

Chloe Coleou

James G Haug

Stephen C Balkunas

Ali E Abdou

A downhole neutron generator includes a housing, a gas reservoir positionable within the housing, a target rod positionable within the housing and having a longitudinal axis aligned with a central axis of the housing, an ion source positionable adjacent to the gas reservoir and between the target rod and the gas reservoir, and a target positionable on a surface of the target rod facing the ion source. The target includes a first metal layer on the surface of the target rod and a second metal layer positionable adjacent to the first metal layer facing the ion source. The second metal layer is a scandium layer.

Scandium target for a neutron generator for wellbore logging

Systems and methods are provided for operating and constructing a neutron generator. In some examples, an ion source within a neutron generator may include a hot cathode; at least one cylindrical sleeve coupled to an exterior surface of the hot cathode; at least one electrode coupled to an interior surface of the neutron generator; and at least one mounting flange, wherein a proximal end of the at least one mounting flange is coupled to the at least one cylindrical sleeve and a distal end of the at least one mounting flange is coupled to the at least one electrode.

Hot cathode for an ion source of a neutron generator

Systems and techniques are provided for optimizing the performance of a target for a downhole neutron generator. An example method can include disposing a first source material and a first substrate in a vacuum chamber at an initial temperature, evaporating the first source material to be deposited onto a surface of the first substrate, monitoring a temperature of the first substrate during the evaporation of the first source material, and determining a thermal equilibrium process temperature at which the temperature of the first substrate is stabilized. The example method can further include disposing a second source material and a second substrate in the vacuum chamber at the thermal equilibrium process temperature, evaporating the second source material to be deposited onto a surface of the second substrate, and obtaining the second substrate deposited with the second source material for a target of a downhole neutron generator.

Optimization of a target of a downhole neutron generator

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).

Rugged semiconductor radiation detector

Methods and related systems are described for gamma-ray detection. A gamma-ray detector is made depending on its properties and how those properties are affected by the data analysis. Desirable properties for a downhole detector include; high temperature operation, reliable/robust packaging, good resolution, high countrate capability, high density, high Z, low radioactive background, low neutron cross-section, high light output, single decay time, efficiency, linearity, size availability, etc. Since no single detector has the optimum of all these properties, a downhole tool design preferably picks the best combination of these in existing detectors, which will optimize the performance of the measurement in the required environment and live with the remaining non-optimum properties. A preferable detector choice is one where the required measurement precision (logging speed) is obtained for all of the required inelastic elements and/or minimization of unwanted background signals that complicate the data analysis.

Gamma-ray detectors for downhole applications

Illustrative embodiments of the present invention are directed to devices and methods for ion generation. One such device includes a substrate. The substrate is disposed within a housing that is configured to contain a gas. The substrate includes an interior surface that at least partially defines an interior volume. The substrate also includes a number of channels with walls. Nano-tips are disposed on the walls of the channels.

Device and method for ion generation

Apparatus and method for detecting radiation-of-interest, such as neutron radiation, employs a gas chamber, a gas that responds to ionizing particles by producing electrons and ions, a cathode that attracts ions, and a supporting layer with a conductive pathway. The conductive pathway collects electrons and responds to electrons that drift towards the conductive pathway by inducing production of further electrons and ions within the gas. The electrons that are collected at the conductive pathway and/or the ions that drift away from the conductive pathway will induce an electrical signal, which can be used to detect the radiation-of-interest.

Apparatus and method for detecting radiation

Illustrative embodiments of the present disclosure are directed to devices and methods for X-ray monitoring. Various embodiments of the present disclosure use a target that incorporates a monitor layer. The monitor layer is disposed adjacent to a target layer so that electrons that pass through the target layer enter the monitor layer. As electrons enter the monitor layer, electrical charge is generated within the monitor layer. This electrical charge is measured and used to determine a characteristic of the X-ray generation within the target layer.

Device and method for monitoring X-ray generation

A nuclear tool includes a tool housing; a neutron generator disposed in the tool housing; and a solid-state neutron monitor disposed proximate the neutron generator for monitoring the output of the neutron generator. A method for constructing a nuclear tool includes disposing a neutron generator in a tool housing; and disposing a solid-state neutron monitor proximate the neutron generator for monitoring the output of the neutron generator. A method for logging a formation includes disposing a nuclear tool in a wellbore penetrating the formation, wherein the nuclear tool comprises a neutron generator and a solid-state neutron monitor disposed proximate the neutron generator; generating neutrons from the neutron generator; monitoring neutrons generated by the neutron generator using the solid-state neutron monitor; detecting signals generated from the neutrons traveling in the formation; and correcting the detected signals, based on signal strength detected by the solid-state neutron monitor, to produce corrected signals.

Downhole tools with solid-state neutron monitors

Devices, methods, and related systems are described for measuring a property of a fluid, including density, in a subterranean environment. A device includes a pressure housing having one or more windows formed in the pressure housing and a flow device arranged in the pressure housing for the fluid to flow through the flow device. Further, a radiation source is mounted within the pressure housing approximate a first source window configured to generate particles into the fluid. The device includes a detector supported by the pressure housing and positioned approximate a first detector window of the one or more windows. The first detector window is located between the detector and the flow device. The detector can be a solid state beta particle detector with a wide band gap, such as the diamond detector, and the radiation source can be a beta particle source, such as a strontium 90 source.

Fluidic density measurements based on beta particles detection

Methods and devices relating to a radiation detector comprising of a gas chamber having a cathode plate and a substrate separated by a gap. An array of nano-tips deposited on the substrate that forms an anode structure for electron charge collection. An external power source in communication with the cathode plate and the substrate, wherein the external power source is capable of generating a plurality of regions and each region includes an electric field near each nano-tip of the array of the nano-tips that results in initiating a radiation induced controlled discharge of electrons and ions from at least one gas or at least one gas mixture. Finally, the plurality of regions include multiple generated electric fields near tips of the array of nano-tips such as CNTs, that communicatively create a conductive path between the cathode plate and the substrate, the radiation detector is capable of determining at least one radiation property.

Nano-tips based gas ionization chamber for neutron detection

A betatron structure having a donut-shaped vacuum chamber, wherein the vacuum chamber is made up of two or more pieces bonded together; an injector positioned within the vacuum chamber; and two or more magnets positioned to the outside of the vacuum chamber. A method of manufacturing a betatron structure, including: (a) fabricating two or more pieces; (b) positioning an injector on one of the two or more pieces; and (c) bonding the two or more pieces such that when bonded, the substrates form a hollow donut-shaped chamber.

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Needham, MA, United States of America

Zilu Zhou