Schlumberger Technology Corporation

Services Petroliers Schlumberger

Markus Berheide

Bradley Albert Roscoe

James A Grau

Zilu Zhou

Christian Stoller

Jeffrey Miles

Kenneth Edward Stephenson

Peter D Wraight

Olivier G Philip

Timothy Spillane

Rod W Shampine

Matthieu Simon

Martin G Luling

Felix K Chen

Dominic Vincent Perroni

Wolfgang P Ziegler

Cornelis Huiszoon

Joyce Wong

James Leslie Thornton

Marie-Laure Mauborgne

Fabien Haranger

Joshua Wayne Gibson

Brad Roscoe

Ahmed Amine Mahjoub

Jim A Grau

Jing Qian

A system includes a neutron source that emits neutrons. The system also includes a vessel that holds a lithium-containing material including a lithium-sorbent material and a lithium-containing brine. Further, the system includes a neutron detector that receives a subset of the neutrons emitted from the neutron source that are transmitted through the lithium-sorbent material and the lithium-containing brine. The neutron detector also determines a concentration of lithium based on the received subset of neutrons.

Lithium detection apparatus systems and methods

A subsurface logging tool that is deployable in a wellbore that traverses a formation includes a gamma-ray scintillation detector with a thallium-based scintillator material. The scintillator material is suitable for high-temperature downhole environments (i.e., above 70&#xb0; C.). As such, the scintillator material improves the performance of oilfield measurement(s) at temperatures above 70&#xb0; C. and at least up to 175&#xb0; C., when compared with the use of the other materials. The scintillator material may have an effective atomic number of at least sixty. The scintillator material may have the chemical formula TlLiYCeCl, where x is 0 to 1. Lithium (Li) may be partially or completely replaced by another alkali metal or by indium (In). Yttrium (Y) is partially or completely replaced by another rare earth element. Chlorine (Cl) is partially or completely replaced by another halide.

Nuclear well logging tool with at least one gamma-ray scintillation detector employing a thallium-based scintillator material

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

Systems and methods for estimating absolute elemental concentrations of a subterranean formation from neutron-induced gamma-ray spectroscopy are provided. In one example, a system for estimating an absolute yield of an element in a subterranean formation may include a downhole tool and data processing circuitry. The downhole tool may include a neutron source to emit neutrons into the formation, a neutron monitor to detect a count rate of the emitted neutrons, and a gamma-ray detector to obtain gamma-ray spectra deriving at least in part from inelastic gamma-rays produced by inelastic scattering events and neutron capture gamma-rays produced by neutron capture events. The data processing circuitry may be configured to determine a relative elemental yield from the gamma-ray spectra and to determine an absolute elemental yield based at least in part on a normalization of the relative elemental yield to the count rate of the emitted neutrons.

Absolute elemental concentrations from nuclear spectroscopy

Devices may include a scintillation detection device including a scintillator, a photon detector at least partially enclosed by the scintillator, and at least one reflector at least partially enclosing the scintillator. In another aspect, an oilfield wellbore device may include an oilfield string with at least one scintillation detection device on the string and a pressure housing enclosing the one or more scintillation detection devices. In another aspect, a method of measuring radiation in an oil and gas well may include conveying at least one scintillation detection device to at least one zone of interest in the oil and gas well and recording data from at least one scintillation detection device as a function of location in the well.

Compact scintillation detector

Methods and downhole tools involving neutron-absorbing gamma ray windows are provided. One such method involves emitting neutrons from a neutron source in a downhole tool in a well into a surrounding geological formation. This may produce formation gamma rays through interactions between the neutrons and elements of the geological formation. The formation gamma rays may be detected by a gamma ray detector when the gamma rays pass via a gamma ray window that includes a neutron-absorbing material disposed in a substrate material of the downhole tool. The gamma ray window may be both more transmissive of gamma rays than the substrate material and less transmissive of neutrons than a window without the neutron-absorbing material. This may decrease a neutron flux that would otherwise reach the gamma ray detector and the tool materials surrounding it and thus would otherwise lead to a background signal contaminating a signal corresponding to the detected formation gamma rays.

Neutron-absorbing gamma ray window in a downhole tool

A method for estimating an aspect of a formation using a nuclear spectroscopy tool includes placing a nuclear spectroscopy tool into a borehole and emitting neutrons such that some of the neutrons generate gamma rays from a formation adjacent the nuclear spectroscopy tool and some of the neutrons generate gamma rays from elements within the nuclear spectroscopy tool. An energy spectrum of gamma rays induced by the emitted neutrons can be detected. The energy spectrum includes a background having a plurality of measured spectral components. A background ratio between at least one spectral component of the background and another measured spectral component can be determined or estimated in accordance with environmental measurements. The detected gamma ray spectra can be analyzed using a combination of standard spectra and subtracting at least one spectral component of the background in accordance with the background ratio.

Environmental corrections in nuclear spectroscopy using variable element ratio

Composition-matched downhole tools and methods for using such tools are provided. One such method includes emitting neutrons using a neutron source in the downhole tool to generate formation gamma rays in a surrounding formation. At the same time, however, some of the neutrons may interact with different parts of the downhole tool to form tool gamma rays. The gamma ray spectra of at least some of the formation gamma rays and the tool gamma rays may be detected using a gamma ray detector. The tool gamma rays from the different parts of the tool may have a substantially similar spectral shape. As such, a processor may be used to analyze the spectra of the tool gamma rays using a single tool background standard, thereby simplifying the analysis and improving the precision of the results.

Composition-matched inelastic or capture spectroscopy tool

Borehole logging tools and systems that include a scintillator positioned to interact with scattered source neutrons that are received from a target formation. The scintillator emits luminescence in response to interaction with the scattered neutrons. The scintillator includes an aluminofluoride host material (e.g., LiCAF). In a specific embodiment, the aluminofluoride host material is doped with europium. In a further specific embodiment, a processor distinguishes scattered neutrons from gamma rays based upon identifying a peak within an output signal from the scintillator. In yet another specific embodiment, a system includes a first scintillator and a second scintillator. The processor subtracts luminescence generated by the second scintillator from luminescence generated by the first scintillator to identify a neutron response of the first scintillator.

Scintillator-based neutron detector for oilfield applications

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

A method for estimating an aspect of a formation using a nuclear spectroscopy tool includes placing a nuclear spectroscopy tool including a neutron source and a gamma ray detector into a borehole and performing a plurality of environmental measurements. Neutrons are emitted from the nuclear spectroscopy tool such that some of the neutrons generate gamma rays from a formation adjacent the nuclear spectroscopy tool, some of the neutrons generate gamma rays from elements within the nuclear spectroscopy tool and some of the neutrons generate gamma rays from an element in the drilling mud. An energy spectrum of gamma rays induced by the emitted neutrons can be detected with the tool and analyzed using a combination of standard spectra including at least two sub-standards that represent a common element or group of elements and that are differentiated based on location of neutron interaction, such as where the neutrons thermalize.

Nuclear spectroscopy corrections using multiple standards and spatial regions

The invention provides a method for optimizing the spectroscopy performance of a spectroscopy scintillator by surrounding the scintillator by a reflector material, performing a scan measuring resolution and light output at three or more axial locations on the crystal, where at least one location is close to the PMT or below the crystal (near the PMT) at least one location is at the end away from the PMT of the scintillator), and adjusting the surface finish of the crystal and/or the reflector to obtain equal light output and optimal resolution over the length and different azimuth of the crystal.

Method for optimizing the spectral performance of scintillator crystals

Methods and related systems are described for the detection of nuclear radiation. The system can include a scintillator material that intrinsically generates radiation and a photodetection system coupled to the scintillator material and adapted to generate electrical signals based on light emitted from the scintillator material. A processing system adapted and programmed to receive the electrical signals, to generate a count rate reference value based at least in part on electrical signals generated in response to the light emitted from the scintillator material due to the intrinsically generated radiation.

Growing community of inventors

Medford, MA, United States of America

Markus Berheide