US20210132252A1 - Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole - Google Patents
Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole Download PDFInfo
- Publication number
- US20210132252A1 US20210132252A1 US17/150,894 US202117150894A US2021132252A1 US 20210132252 A1 US20210132252 A1 US 20210132252A1 US 202117150894 A US202117150894 A US 202117150894A US 2021132252 A1 US2021132252 A1 US 2021132252A1
- Authority
- US
- United States
- Prior art keywords
- deuterium
- neutron
- target
- tritium
- tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 11
- 238000005259 measurement Methods 0.000 title description 19
- 239000004568 cement Substances 0.000 title description 8
- 230000035945 sensitivity Effects 0.000 title description 6
- 238000006243 chemical reaction Methods 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 24
- 230000004044 response Effects 0.000 claims abstract description 12
- 230000007246 mechanism Effects 0.000 claims abstract description 8
- 229910052805 deuterium Inorganic materials 0.000 claims description 26
- 229910052722 tritium Inorganic materials 0.000 claims description 21
- 230000001133 acceleration Effects 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 3
- WHXSMMKQMYFTQS-BJUDXGSMSA-N (6Li)Lithium Chemical compound [6Li] WHXSMMKQMYFTQS-BJUDXGSMSA-N 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- SWQJXJOGLNCZEY-BJUDXGSMSA-N helium-3 atom Chemical compound [3He] SWQJXJOGLNCZEY-BJUDXGSMSA-N 0.000 claims description 2
- 239000000376 reactant Substances 0.000 claims 8
- 150000002500 ions Chemical class 0.000 description 23
- YZCKVEUIGOORGS-OUBTZVSYSA-N Deuterium Chemical compound [2H] YZCKVEUIGOORGS-OUBTZVSYSA-N 0.000 description 11
- 230000001965 increasing effect Effects 0.000 description 10
- YZCKVEUIGOORGS-NJFSPNSNSA-N Tritium Chemical compound [3H] YZCKVEUIGOORGS-NJFSPNSNSA-N 0.000 description 9
- 239000007789 gas Substances 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 230000005291 magnetic effect Effects 0.000 description 6
- 238000000605 extraction Methods 0.000 description 5
- 230000004907 flux Effects 0.000 description 5
- 230000004927 fusion Effects 0.000 description 5
- 238000010884 ion-beam technique Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 238000011835 investigation Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- -1 deuterium ions Chemical class 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 230000003628 erosive effect Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000010849 ion bombardment Methods 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 229910001507 metal halide Inorganic materials 0.000 description 2
- 150000005309 metal halides Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- GSOLWAFGMNOBSY-UHFFFAOYSA-N cobalt Chemical compound [Co][Co][Co][Co][Co][Co][Co][Co] GSOLWAFGMNOBSY-UHFFFAOYSA-N 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000004320 controlled atmosphere Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- 150000004678 hydrides Chemical class 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- KZUNJOHGWZRPMI-UHFFFAOYSA-N samarium atom Chemical compound [Sm] KZUNJOHGWZRPMI-UHFFFAOYSA-N 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
- G01V5/04—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
- G01V5/08—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
- G01V5/10—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources
- G01V5/101—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources and detecting the secondary Y-rays produced in the surrounding layers of the bore hole
- G01V5/102—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources and detecting the secondary Y-rays produced in the surrounding layers of the bore hole the neutron source being of the pulsed type
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H3/00—Production or acceleration of neutral particle beams, e.g. molecular or atomic beams
- H05H3/06—Generating neutron beams
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
- G01V5/04—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
- G01V5/08—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
- G01V5/10—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
- G01V5/04—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
- G01V5/08—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
- G01V5/10—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources
- G01V5/107—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources and detecting reflected or back-scattered neutrons
- G01V5/108—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources and detecting reflected or back-scattered neutrons the neutron source being of the pulsed type
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H5/00—Direct voltage accelerators; Accelerators using single pulses
- H05H5/02—Details
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H6/00—Targets for producing nuclear reactions
Definitions
- the present invention relates generally to near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole, and in a particular though non-limiting embodiment to methods and means of substantially increasing the output of a deuterium-tritium pulsed neutron generator for use in neutron porosity borehole logging without dramatically increasing the length or diameter of the tool, or thereby increasing power consumption to unsustainable levels or reducing the lifetime of the generator tube.
- the ion source type most widely used is the Penning type which has the advantage that it is robust, has a cold cathode and a long operating life as a consequence, yields considerable discharge currents at low pressures, in the order of 10 A/torr, has a high extraction efficiency of 20 to 40% and has small physical dimensions.
- This type of source requires a magnetic field on the order of a thousand-gauss parallel to the axis of the ionization chamber, which introduces a considerable transverse inhomogeneity of the ion flow density in the interior of the discharge and at the level of extraction occurring along the common axis of the field and of the source.
- Neutron generator tubes are generally constructed as sealed tubes containing a gas mixture of deuterium and tritium under low pressure, from which the ion source forms a confined ionized gas.
- the emission (or extraction) port is provided in the cathode, while the acceleration (and extraction) electrode renders it possible to project the ion beam axially onto a target electrode.
- the fusion deuterium-tritium reaction, 3 H+ 2 H ⁇ 4 He+n, which supplies neutrons of 14 MeV is most widely used because of its great effective sectional surface at comparatively low ion energy levels. Whatever reaction is used, however, the number of neutrons obtained per unit charge going through the beam always increases proportionally as the energy of the ions directed towards a dense target itself increases, to well beyond the ion energies obtained in presently available sealed tubes which are fed by a high voltage potential which seldom exceeds 250 kV. In almost all borehole neutron porosity logging operations, the reaction is limited to a maximum of 90 kV due to the issues with creating and controlling larger potentials within the confines of a small 33 ⁇ 8′′ or 1 11/16′′ diameter pressure housings as typically required.
- Erosion of the target by the ion bombardment is one of the most determining factors among the principal constraints governing the operating life of a neutron generator tube.
- the erosion is a function of the chemical composition and the structure of the target on the one hand, and of the energy of the incident ions and their density distribution profile on the impact surface on the other hand.
- the target is formed from a material capable of forming a hydride (titanium, scandium, zirconium, erbium, etc.) and of binding and releasing considerable quantities of hydrogen without an inadmissible disturbance of its mechanical strength, and the total quantity bound is a function of the temperature of the target and of the hydrogen pressure in the tube.
- the target materials used are deposited in the form of thin layers whose thickness is limited by adhesion problems of the layer on its support.
- a means of slowing down the erosion of the target consists, for example, in forming the active absorbing layer from a superimposition of identical layers insulated from one another by diffusion barriers.
- the thickness of each of the active layers is of the order of the penetration depth of the deuterium ions which are to strike the target.
- One method of protecting the target, and thus of increasing the operating life of the tube, is to influence the ion beam in such a way as to improve its density distribution profile on the impact surface.
- None of the prior art teaches of practical methods or means that can be employed to double the effective output of the tube without increasing the high voltage potential without reducing the lifetime of the tube, nor teaches of a method or means to measure near-field and far-field physics, such that distinct radial components to the measurement's resolution can be determined (i.e., radial resolution of more than “1”). Further, none of the known art teaches a method or means to selectively switch between various fusion physics types during operation. Moreover, none of the known art teaches a method or means to alternate between various fusion physics types during operation.
- U.S. Pat. No. 3,546,512 to Frentrop discloses a permanent magnet that is outgassed for use in a controlled atmosphere by heating a ferromagnetic material to a temperature at which an irreversible loss of remanence takes place, but below the temperature at which material effects substantially reduce or remove all remanence without further special heat treatment. Gases emitted from the heated surfaces of the magnet then are evacuated. Permanent magnetic properties are not destroyed by this heat treatment, and a magnetic field of substantial strength subsequently is produced by magnetizing the outgassed material.
- a specific embodiment of the disclosure enables a hollow cylindrical ion source magnet to be placed within the envelope of a small neutron generator to provide both a magnetic field and an ion source electrode. The assembled generator then is outgassed and sealed. Subsequent magnetization enables the electrode to produce the high intensity magnetic field needed for ion generation.
- U.S. Pat. No. 4,996,017 to Etheridge discloses a neutron generating system comprising a hermetically sealed housing containing an ionizable gas and a ring anode and target cathode of a Penning ion source.
- the housing is provided with a recess axially oriented relative to the ring anode and target cathode and adapted to accept a removable samarium/cobalt magnet such that degassing and sealing of the housing can be performed in the absence of the permanent magnet.
- U.S. Pat. No. 5,215,703 to Bernardet discloses a neutron generator tube including an ion source having at least one anode, at least one cathode having at least one extraction port, and an accelerator electrode arranged so as to project at least one ion beam from the ion source onto a target to produce thereat a reaction resulting in emission of neutrons.
- the ion source is arranged on at least a portion of a first surface of revolution and is constructed so as to produce emission of ions radially outwardly from such surface.
- the accelerator electrode is arranged on at least a portion of a second surface of revolution the surrounds the aforesaid first surface, the target being positioned on at least a portion of a third surface of revolution which surrounds the aforesaid second surface.
- Increased neutron flux is thereby achieved for a given size generator tube, and for a given neutron flux a significantly reduced ion bombardment density is produced at the target and so achieves extended target life.
- U.S. Pat. No. 9,575,206 to Guo et al. discloses a neutron activation measurement technique that can be used to evaluate various properties of a subterranean well structure.
- a logging tool can be positioned within a wellbore, such that neutrons generated by a neutron source are directed towards well structure.
- the well structure In response to the neutrons, the well structure emits gamma rays. A portion of the gamma rays can be detected by a gamma detector.
- the well structure can be constructed of materials that include one or more doping materials.
- a method of controlling a neutron porosity tool having an electronic neutron generator arrangement and a control mechanism that provides voltage and pulses to an electronic neutron tube thereby enabling the production of two distinct neutron energies to provide radial discrimination of porosity is also provided, the method including at least: controlling a bipolar neutron tube to produce two distinct neutron reactions; using a control circuit to modify the output of a pulser circuit; and using a plurality of neutron detectors to determine formation response offsets.
- FIG. 1 illustrates a downhole tool housing located within a cased borehole, where the casings are cemented to each other and to the formation; in this example, two spheres illustrate the difference in depth of investigation of high and low neutron energies.
- FIG. 2 illustrates a schematic layout of a typical pulsed neutron tube.
- FIG. 4 illustrates one embodiment of a unipolar pulsed neutron tube, illustrating the ability to combine two tubes into a single package with a common target electrode. Further illustrating the ability to effectively double the output of a single target-plane while using a single generator.
- FIG. 6 illustrates one embodiment of a bipolar pulsed neutron tube, illustrating the ability to combine two tubes into a single package with a common target electrode, with each tube capable of developing differing tube voltages. Further illustrating the ability to select which tube and, therefore, which energy neutron would be emitted by the common linked targets, through use of two pulser and radio-frequency cavities.
- FIG. 1 illustrates an electronic neutron source located within a downhole tool pressure housing [ 101 ], which is located within a well casing [ 103 ] filled with well or drilling fluid [ 102 ].
- the first well casing [ 103 ] is cemented [ 104 ] to a further casing [ 105 ] that is again cemented [ 106 ] to the well formation [ 107 ].
- the energy of produced neutrons [ 108 , 109 ] determines the depth of investigation of the measurement and, therefore, the offset of the detectors of optimum sensitivity.
- the lower energy neutrons produced through a deuterium-deuterium (DD) reaction would produce a measurement that is more sensitive to porosity changes within a near-field region [ 108 ], such as the cement immediately surrounding a borehole [ 104 ].
- a deuterium-tritium (DT) reaction would be sensitive to a near-and-outer-field zone [ 109 ], such as the formation [ 107 ] and outer cemented casing annuli [ 106 ] of a well.
- the bias between the DD measurement and the DT measurement can be used to indicate whether increased porosity (as could be expected by a fluid channel in the cement) is in the near-field zone [ 108 ] or outer-field zone [ 109 ].
- the target is typically a metal halide that is doped with tritium, such that the bombardment of the tritium atoms with deuterons produces helium ions and 14.1 MeV neutrons.
- the pulsing technique means that pulses of neutrons are produced and the near [ 201 ] and far [ 202 ] space detectors operate during the time when the generator is not pulsing to collect signals coming back from the surrounding formation without being swamped by primary neutrons arriving directly from the source. To achieve this effect, the pulser signal is typically used to gate the response of the detectors.
- FIG. 4 illustrates one embodiment where the neutron generation tube [ 403 , 404 ] is mirrored around the target, such that a single high voltage generator [ 405 ] is required to operate two halves of a tube with a common target electrode (even if the two physical targets are distinct and separate).
- the effective pulse rate would double, thereby doubling output neutron flux from a pair of co-located targets. This effect ensures that the target region for the conjoined tubes is collocated. Power-wise, the beam current delivery of the high voltage generator would effectively double, but with a half-contribution interlaced from each tube-half [ 403 , 404 ].
- FIG. 5 illustrates an example embodiment of the conjoined common target region scheme illustrated in FIG. 4 .
- a single pulsing regime [ 501 ] is illustrated as a function of voltage between ground [ 504 ] and high-voltage output [ 505 ] versus time [ 503 ].
- Two pulser circuits with a common ground [ 504 ] would operate at a set frequency and duty-cycle but with the each side of the pulser operating [ ⁇ /2] out of phase with the other [ 502 ], such that the positive high-voltage [ 506 ] output is out of phase with the negative high-voltage [ 507 ] output.
- the pulsers operate in phase with each other.
- FIG. 6 illustrates an example embodiment wherein an additional high voltage generator [ 607 ] is included on one side of the conjoined tube [ 604 , 605 ], and the associated target doped with both tritium and deuterium, and an interleaved pulser scheme used as illustrated in FIG. 5 , such that every pulse of neutrons out of the target alternates between 14 MeV neutrons and 2 MeV neutrons.
- the response of the mid-space [ 602 ] and far-space [ 603 ] detectors is individually gated to the separate timing signals of the pulsers [ 609 , 610 ] controlled by a control circuit, such that a separate profile for near-field and far-field porosity response is determined during the same logging run.
- a near space, mid space and far space neutron detector are located upon the axis within a tool housing, along with a neutron generator.
- a radio-frequency cavity within the chamber is driven by a pulser circuit (operating at 1 kHz and 10% duty cycle, for example) which acts to ionize the deuterium gas into positively charged deuterons that are accelerated toward a negative grid (powered by a voltage multiplier) and onto a target.
- the target is typically a metal halide that is doped with tritium, such that the bombardment of the tritium atoms with deuterons produces helium ions and 14.1 MeV neutrons.
- the pulsing technique means that pulses of neutrons are produced, as it permits the near and far space detectors to operate during the time when the generator is not pulsing, to collect signals coming back from the surrounding formation without being swamped by primary neutrons directly from the source. To achieve this, the pulser signal is typically used to gate the response of the detectors.
- the target is doped with both tritium and deuterium, such that either the DT or DD-DT output is selected by simply enabling or disabling the non-target multiplier.
- the neutron generation tube is mirrored around the target, such that a single multiplier is required to operate two halves of a tube with a common target electrode (even if the two physical targets are distinct and separate).
- the effective pulse rate is doubled, thereby doubling the output neutron flux from a pair of co-located targets. This effect ensures that the target region for the conjoined tubes is collocated.
- the beam current delivery of the multiplier effectively doubles, but with a half-contribution interlaced from each tube-half.
- two pulser circuits with a common ground operate at a set frequency and duty-cycle, but with the each side of the pulser operating [ ⁇ /2] out of phase with each other.
- an additional multiplier is included on one side of the conjoined tube, and the associated target doped with both tritium and deuterium, and an interleaved pulser scheme used, so that every pulse of neutrons out of the target alternates between 14.1 MeV neutrons and 2.5 MeV neutrons.
- the response of the mid-space and far-space detectors is individually gated to the separate timing signals of the pulsers, such that a separate profile for near-field and far-field porosity response could be determined during the same logging run.
- the lower energy neutrons produced through a D-D reaction will produce a measurement more sensitive to porosity changes within a near-field region, such as the cement immediately surrounding a borehole, whereas higher energy neutrons produced by a D-T reaction are sensitive to a near-and-outer-field zone such as the formation and outer cemented casing annuli of a well.
- the bias between the DD measurement and the DT measurement is used to indicate whether increased porosity (as could be expected by a fluid channel in the cement) is in the near-field zone or outer-field zone.
- the neutron detectors are helium-3-filled detectors.
- the neutron detectors are lithium-6 glass detectors.
- the source tube is shielded in all but one direction and is manipulated such that it rotates around the tool major axis, such that azimuthal porosity information may be determined through directional bias of the source and/or detectors using neutron moderating or shielding materials.
- the source tubes and detectors are shielded in all but one direction and are manipulated such that they rotate around the tool major axis, such that azimuthal porosity information may be determined through directional bias of the source and/or detectors using neutron moderating or shielding materials.
- technique is combined with ultrasound or x-ray density techniques.
- Radially resolved porosity could be highly advantageous when combined with x-ray, ultrasonic and azimuthal neutron techniques, to map-out (in 3D) the porosity associated with channels or fluid defects in cement surrounding a borehole.
Landscapes
- Physics & Mathematics (AREA)
- High Energy & Nuclear Physics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Plasma & Fusion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Optics & Photonics (AREA)
- Particle Accelerators (AREA)
- Measurement Of Radiation (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
A neutron porosity tool having an electronic neutron generator arrangement and a control mechanism used to provide voltage and pulses to an electronic neutron tube is provided, the neutron generator arrangement including: at least one vacuum tube; at least one ion target; at least one radio-frequency cavity; at least one high-voltage generator; at least two neutron detectors; at least one pulser circuit; and at least one control circuit. A method of controlling a neutron porosity tool having an electronic neutron generator arrangement and a control mechanism that provides voltage and pulses to an electronic neutron tube, the method including at least: controlling a bipolar neutron tube to produce two distinct neutron reactions; using a control circuit to modify the output of a pulser circuit; and using a plurality of neutron detectors to determine formation response offsets.
Description
- The present invention relates generally to near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole, and in a particular though non-limiting embodiment to methods and means of substantially increasing the output of a deuterium-tritium pulsed neutron generator for use in neutron porosity borehole logging without dramatically increasing the length or diameter of the tool, or thereby increasing power consumption to unsustainable levels or reducing the lifetime of the generator tube.
- Since F. M. Penning disclosed a neutron generator in U.S. Pat. No. 2,211,668 consisting of a low-pressure deuterium-filled envelope containing a cathode and an anode disposed in electromagnetic communication with an axially oriented magnetic field ion source, a nuclear reaction producing target, and one or more acceleration electrodes, various other references have been published disclosing additional control mechanisms and improvements. However, the majority of known art relies upon the use of the “Penning” ion source and has been employed extensively in various neutron generator tubes for downhole oil and gas well neutron logging.
- The ion source type most widely used is the Penning type which has the advantage that it is robust, has a cold cathode and a long operating life as a consequence, yields considerable discharge currents at low pressures, in the order of 10 A/torr, has a high extraction efficiency of 20 to 40% and has small physical dimensions. This type of source requires a magnetic field on the order of a thousand-gauss parallel to the axis of the ionization chamber, which introduces a considerable transverse inhomogeneity of the ion flow density in the interior of the discharge and at the level of extraction occurring along the common axis of the field and of the source.
- Neutron generator tubes are generally constructed as sealed tubes containing a gas mixture of deuterium and tritium under low pressure, from which the ion source forms a confined ionized gas. The emission (or extraction) port is provided in the cathode, while the acceleration (and extraction) electrode renders it possible to project the ion beam axially onto a target electrode.
- The fusion deuterium-tritium reaction, 3H+2H→4He+n, which supplies neutrons of 14 MeV is most widely used because of its great effective sectional surface at comparatively low ion energy levels. Whatever reaction is used, however, the number of neutrons obtained per unit charge going through the beam always increases proportionally as the energy of the ions directed towards a dense target itself increases, to well beyond the ion energies obtained in presently available sealed tubes which are fed by a high voltage potential which seldom exceeds 250 kV. In almost all borehole neutron porosity logging operations, the reaction is limited to a maximum of 90 kV due to the issues with creating and controlling larger potentials within the confines of a small 3⅜″ or 1 11/16″ diameter pressure housings as typically required. Deuterium-deuterium reactions, which supply neutrons of 2 MeV would be of use for near-field measurements, where the depth of investigation is required to be significantly smaller, such as the neutron-porosity measurement of cement structures surrounding a borehole, for the benefit of well integrity evaluation during drilling and plug and abandonment operations. However, deuterium-deuterium reactions typically rely upon a tube potential in excess of 160 kV, which is an issue with the aforementioned geometrical constraints of the tool housing, when considering electrical dielectric breakdown strengths of suitable insulators.
- Erosion of the target by the ion bombardment is one of the most determining factors among the principal constraints governing the operating life of a neutron generator tube. The erosion is a function of the chemical composition and the structure of the target on the one hand, and of the energy of the incident ions and their density distribution profile on the impact surface on the other hand. In most cases the target is formed from a material capable of forming a hydride (titanium, scandium, zirconium, erbium, etc.) and of binding and releasing considerable quantities of hydrogen without an inadmissible disturbance of its mechanical strength, and the total quantity bound is a function of the temperature of the target and of the hydrogen pressure in the tube. The target materials used are deposited in the form of thin layers whose thickness is limited by adhesion problems of the layer on its support. A means of slowing down the erosion of the target consists, for example, in forming the active absorbing layer from a superimposition of identical layers insulated from one another by diffusion barriers. The thickness of each of the active layers is of the order of the penetration depth of the deuterium ions which are to strike the target. One method of protecting the target, and thus of increasing the operating life of the tube, is to influence the ion beam in such a way as to improve its density distribution profile on the impact surface. At an overall ion flow on the target which is constant, which leads to a constant neutron emission, this improvement results in a flow density distribution over the entire surface of the target exposed to the ion bombardment which is as uniform as possible. However, the problem that continues to limit the contemporary neutron generator tube is the removal of thermal energy from the target surface of the tube. It is known that the energy of the ion beam striking the target and inducing the desired nuclear reaction will, if too intense, result in high temperature sputtering and thermal failure of the target and thus failure of the neutron generator tube. As a result, most contemporary neutron generator tubes are limited to a tube potential of 80-100 keV and 30-50 uA beam current. The resultant number of output neutrons (14 MeV) is in the region of 5×107 to 1×108 neutrons per second.
- A typical neutron porosity measurement will operate in the range of 0 to 60 porosity units (p.u.), where 100% p.u. would be regarded as a simple infinite volume of water surrounding the tool. Typical accuracies required for the measurement would be +/−0.5% for measurements less than 10 p.u., +/−7% for measurements in the 10 p.u. to 30 p.u. range, and +/−10% in the 30 to 60 p.u. measurement range. As a result of the statistical requirements to match or improve upon these accuracies is highly dependent upon the detected signal, which, again is highly dependent upon the output neutron rate of the generator, most logging speeds are limited to 1800 feet per hour. Logging speeds of 3600 feet per hour are achievable, but at the deficit of accuracy of the measurement.
- None of the prior art teaches of practical methods or means that can be employed to double the effective output of the tube without increasing the high voltage potential without reducing the lifetime of the tube, nor teaches of a method or means to measure near-field and far-field physics, such that distinct radial components to the measurement's resolution can be determined (i.e., radial resolution of more than “1”). Further, none of the known art teaches a method or means to selectively switch between various fusion physics types during operation. Moreover, none of the known art teaches a method or means to alternate between various fusion physics types during operation.
- U.S. Pat. No. 2,211,668 to Penning discloses an electric discharge tube having a plurality of interconnected portions in which the pressure is the same. The ions are produced in a glow discharge taking place in one portion and are accelerated in another portion, and finally strike a disc of impact, which contains a definitive compound to produce the nucleus reaction.
- U.S. Pat. No. 3,546,512 to Frentrop discloses a permanent magnet that is outgassed for use in a controlled atmosphere by heating a ferromagnetic material to a temperature at which an irreversible loss of remanence takes place, but below the temperature at which material effects substantially reduce or remove all remanence without further special heat treatment. Gases emitted from the heated surfaces of the magnet then are evacuated. Permanent magnetic properties are not destroyed by this heat treatment, and a magnetic field of substantial strength subsequently is produced by magnetizing the outgassed material. A specific embodiment of the disclosure enables a hollow cylindrical ion source magnet to be placed within the envelope of a small neutron generator to provide both a magnetic field and an ion source electrode. The assembled generator then is outgassed and sealed. Subsequent magnetization enables the electrode to produce the high intensity magnetic field needed for ion generation.
- U.S. Pat. No. 4,996,017 to Etheridge discloses a neutron generating system comprising a hermetically sealed housing containing an ionizable gas and a ring anode and target cathode of a Penning ion source. The housing is provided with a recess axially oriented relative to the ring anode and target cathode and adapted to accept a removable samarium/cobalt magnet such that degassing and sealing of the housing can be performed in the absence of the permanent magnet.
- U.S. Pat. No. 5,215,703 to Bernardet discloses a neutron generator tube including an ion source having at least one anode, at least one cathode having at least one extraction port, and an accelerator electrode arranged so as to project at least one ion beam from the ion source onto a target to produce thereat a reaction resulting in emission of neutrons. The ion source is arranged on at least a portion of a first surface of revolution and is constructed so as to produce emission of ions radially outwardly from such surface. The accelerator electrode is arranged on at least a portion of a second surface of revolution the surrounds the aforesaid first surface, the target being positioned on at least a portion of a third surface of revolution which surrounds the aforesaid second surface. Increased neutron flux is thereby achieved for a given size generator tube, and for a given neutron flux a significantly reduced ion bombardment density is produced at the target and so achieves extended target life.
- U.S. Pat. No. 8,481,919 to Teague teaches a method and means of creating and controlling the electrical power necessary by serially stepping up the DC reference and creating high potential field control surfaces in order to control either a bipolar or unipolar x-ray tube for the purposes of replacing chemical sources in reservoir logging. Teague also teaches of moveable/manipulatable beam hardening filters and rotating light-house collimation on the source, and the use of gaseous insulators including SF6 as an electrical insulator in a downhole x-ray generator.
- U.S. Pat. No. 9,575,206 to Guo et al. discloses a neutron activation measurement technique that can be used to evaluate various properties of a subterranean well structure. In an example implementation, a logging tool can be positioned within a wellbore, such that neutrons generated by a neutron source are directed towards well structure. In response to the neutrons, the well structure emits gamma rays. A portion of the gamma rays can be detected by a gamma detector. To enhance the well structure's response to neutron activation, the well structure can be constructed of materials that include one or more doping materials.
- Finally, U.S. Pat. No. 9,472,370 to Perkins discloses a neutron radiation generator that includes at least three extractor electrodes, with an ion source upstream of the at least three extractor electrodes to emit ions in a downstream direction toward the at least three extractor electrodes. There is a target downstream of the at least three extractor electrodes. The at least three extractor electrodes have independently selectable potentials so as to allow direction of an ion beam, formed from the ions, by the independently selectable potentials, toward different longitudinal and lateral regions of the target.
- A neutron porosity tool having an electronic neutron generator arrangement and a control mechanism used to provide voltage and pulses to an electronic neutron tube so that the output of two neutron reaction planes from collocated target planes in a wellbore environment is provided, the neutron generator arrangement including: at least one vacuum tube; at least one ion target; at least one radio-frequency cavity; at least one high-voltage generator; at least two neutron detectors; at least one pulser circuit; and at least one control circuit.
- A method of controlling a neutron porosity tool having an electronic neutron generator arrangement and a control mechanism that provides voltage and pulses to an electronic neutron tube thereby enabling the production of two distinct neutron energies to provide radial discrimination of porosity is also provided, the method including at least: controlling a bipolar neutron tube to produce two distinct neutron reactions; using a control circuit to modify the output of a pulser circuit; and using a plurality of neutron detectors to determine formation response offsets.
-
FIG. 1 illustrates a downhole tool housing located within a cased borehole, where the casings are cemented to each other and to the formation; in this example, two spheres illustrate the difference in depth of investigation of high and low neutron energies. -
FIG. 2 illustrates a schematic layout of a typical pulsed neutron tube. -
FIG. 3 illustrates one embodiment of a bipolar pulsed neutron tube, illustrating the ability to combine two high-voltage generators to produce a higher tube voltage without changing the outer diameter of the downhole tool housing. -
FIG. 4 illustrates one embodiment of a unipolar pulsed neutron tube, illustrating the ability to combine two tubes into a single package with a common target electrode. Further illustrating the ability to effectively double the output of a single target-plane while using a single generator. -
FIG. 5 illustrates two embodiments of pulsing schemes that may be used to control either a single-polar tube or a pair of tubes with a common target. Further illustrating the ability to select neutron-burst energies through the selection of pulse-schemes to a common target. -
FIG. 6 illustrates one embodiment of a bipolar pulsed neutron tube, illustrating the ability to combine two tubes into a single package with a common target electrode, with each tube capable of developing differing tube voltages. Further illustrating the ability to select which tube and, therefore, which energy neutron would be emitted by the common linked targets, through use of two pulser and radio-frequency cavities. - The methods and means described herein enable pulsed neutron generators to substantially increase their output and rapidly switch between output neutron energies while maintaining a single reactance plane, within the environment of a borehole. Control mechanisms for various neutron tube geometries and high-voltage generators that power said neutron tubes are provided, the tool including at least a pulsed neutron tube, a radio-frequency cavity, a high-voltage generator, and an electronic pulsing scheme to selectively switch said radio-frequency cavity.
- With reference now to the attached Figures,
FIG. 1 illustrates an electronic neutron source located within a downhole tool pressure housing [101], which is located within a well casing [103] filled with well or drilling fluid [102]. The first well casing [103] is cemented [104] to a further casing [105] that is again cemented [106] to the well formation [107]. The energy of produced neutrons [108, 109] determines the depth of investigation of the measurement and, therefore, the offset of the detectors of optimum sensitivity. In this example, the lower energy neutrons produced through a deuterium-deuterium (DD) reaction would produce a measurement that is more sensitive to porosity changes within a near-field region [108], such as the cement immediately surrounding a borehole [104]. Whereas higher energy neutrons produced by a deuterium-tritium (DT) reaction would be sensitive to a near-and-outer-field zone [109], such as the formation [107] and outer cemented casing annuli [106] of a well. The bias between the DD measurement and the DT measurement can be used to indicate whether increased porosity (as could be expected by a fluid channel in the cement) is in the near-field zone [108] or outer-field zone [109]. -
FIG. 2 illustrates a typical example of a contemporary neutron porosity logging tool, wherein a near space [201] and far space [202] neutron detector are located upon the axis within a tool housing, along with a neutron tube [203]. A ‘replenisher’ current [206] causes the production of deuterium gas within a vacuum chamber within the tube [203]. A radio-frequency (RF) cavity within the chamber is driven by a pulser circuit [205] (operating at 1 kHz and 10% duty cycle, for example) which acts to ionize the deuterium gas into positively charged deuterons that are accelerated toward a negative grid, powered by a high voltage generator [204], and onto a target. The target is typically a metal halide that is doped with tritium, such that the bombardment of the tritium atoms with deuterons produces helium ions and 14.1 MeV neutrons. The pulsing technique means that pulses of neutrons are produced and the near [201] and far [202] space detectors operate during the time when the generator is not pulsing to collect signals coming back from the surrounding formation without being swamped by primary neutrons arriving directly from the source. To achieve this effect, the pulser signal is typically used to gate the response of the detectors. -
FIG. 3 illustrates one embodiment, wherein a cathode (filament) within a source tube [304] is held at a high direct current potential (such as 85 kV, for example) by a positive high-voltage generator [305], in addition to the target [extractor] electrode being held at −85 kV, by a negative high-voltage generator [306]. The result would be a potential difference across the tube [304] cavity of 190 kV, enough to enable a DD reaction (2 MeV), if the target is doped with deuterium. A mid-space detector [302] can be added between the near [301] and far [303] space detectors, such that sensitivity to the 2 MeV neutron physics is optimized. In another embodiment, the pulser's DC level is elevated to a high positive potential, such that the potential difference between the RF cavity and the target electrode is at a sufficient potential to accelerate the deuterons to fusion energies. In another embodiment, the target is doped with both tritium and deuterium, such that the either DT or DD-DT output can be selected by simply enabling or disabling the non-target multiplier [305], by a control circuit. -
FIG. 4 illustrates one embodiment where the neutron generation tube [403, 404] is mirrored around the target, such that a single high voltage generator [405] is required to operate two halves of a tube with a common target electrode (even if the two physical targets are distinct and separate). By using two pulsers [406, 407] that are out of phase with each other, the effective pulse rate would double, thereby doubling output neutron flux from a pair of co-located targets. This effect ensures that the target region for the conjoined tubes is collocated. Power-wise, the beam current delivery of the high voltage generator would effectively double, but with a half-contribution interlaced from each tube-half [403,404]. -
FIG. 5 illustrates an example embodiment of the conjoined common target region scheme illustrated inFIG. 4 . A single pulsing regime [501] is illustrated as a function of voltage between ground [504] and high-voltage output [505] versus time [503]. Two pulser circuits with a common ground [504] would operate at a set frequency and duty-cycle but with the each side of the pulser operating [π/2] out of phase with the other [502], such that the positive high-voltage [506] output is out of phase with the negative high-voltage [507] output. In another embodiment, the pulsers operate in phase with each other. -
FIG. 6 illustrates an example embodiment wherein an additional high voltage generator [607] is included on one side of the conjoined tube [604, 605], and the associated target doped with both tritium and deuterium, and an interleaved pulser scheme used as illustrated inFIG. 5 , such that every pulse of neutrons out of the target alternates between 14 MeV neutrons and 2 MeV neutrons. In this manner, the response of the mid-space [602] and far-space [603] detectors is individually gated to the separate timing signals of the pulsers [609, 610] controlled by a control circuit, such that a separate profile for near-field and far-field porosity response is determined during the same logging run. - In one example embodiment, a near space, mid space and far space neutron detector are located upon the axis within a tool housing, along with a neutron generator. A radio-frequency cavity within the chamber is driven by a pulser circuit (operating at 1 kHz and 10% duty cycle, for example) which acts to ionize the deuterium gas into positively charged deuterons that are accelerated toward a negative grid (powered by a voltage multiplier) and onto a target. The target is typically a metal halide that is doped with tritium, such that the bombardment of the tritium atoms with deuterons produces helium ions and 14.1 MeV neutrons. The pulsing technique means that pulses of neutrons are produced, as it permits the near and far space detectors to operate during the time when the generator is not pulsing, to collect signals coming back from the surrounding formation without being swamped by primary neutrons directly from the source. To achieve this, the pulser signal is typically used to gate the response of the detectors.
- In one embodiment the cathode circuit's DC level is held at a high potential (such as 85 kV), in addition to the target [extractor] electrode being held at −85 kV. The result is a potential difference across the RF cavity of 190 kV, enough to enable a DD reaction (2.5 Mev), if the target is doped with deuterium. A mid-space detector is located between the near and far space, such that sensitivity to the 2.5 MeV neutron physics is optimized. In another embodiment, the pulser's DC level is elevated to a high positive potential, such that the potential difference between the RF cavity and the target electrode is at a sufficient potential to accelerate the deuterons to fusion energies.
- In another example embodiment, the target is doped with both tritium and deuterium, such that either the DT or DD-DT output is selected by simply enabling or disabling the non-target multiplier.
- In another embodiment, the neutron generation tube is mirrored around the target, such that a single multiplier is required to operate two halves of a tube with a common target electrode (even if the two physical targets are distinct and separate). By using two pulsers disposed out of phase with each other, the effective pulse rate is doubled, thereby doubling the output neutron flux from a pair of co-located targets. This effect ensures that the target region for the conjoined tubes is collocated. Power-wise, the beam current delivery of the multiplier effectively doubles, but with a half-contribution interlaced from each tube-half. In the conjoined common target region scheme, two pulser circuits with a common ground operate at a set frequency and duty-cycle, but with the each side of the pulser operating [π/2] out of phase with each other.
- In another example embodiment, the pulsers operate in phase with each other, the benefit being to double the output of the tube without increasing the thermal dissipation load on the individual target faces. A doubling of neutron output flux permits a doubling of possible logging speeds (up to 7,200 ft/hr., for example) without reducing the statistical quality (accuracy) of the measured porosity response.
- In another example embodiment, an additional multiplier is included on one side of the conjoined tube, and the associated target doped with both tritium and deuterium, and an interleaved pulser scheme used, so that every pulse of neutrons out of the target alternates between 14.1 MeV neutrons and 2.5 MeV neutrons. In this way, the response of the mid-space and far-space detectors is individually gated to the separate timing signals of the pulsers, such that a separate profile for near-field and far-field porosity response could be determined during the same logging run.
- Those of ordinary skill in the art will understand that in this context, D+T→n+4He (En=14.1 MeV).
- Ordinarily skilled artisans will also appreciate that in this context, D+D→n+3He (En=2.5 MeV).
- As the energy of produced neutrons determines the depth of investigation of the measurement, and therefore the offset of the detectors of optimum sensitivity, the lower energy neutrons produced through a D-D reaction will produce a measurement more sensitive to porosity changes within a near-field region, such as the cement immediately surrounding a borehole, whereas higher energy neutrons produced by a D-T reaction are sensitive to a near-and-outer-field zone such as the formation and outer cemented casing annuli of a well. The bias between the DD measurement and the DT measurement is used to indicate whether increased porosity (as could be expected by a fluid channel in the cement) is in the near-field zone or outer-field zone.
- In another embodiment, multiple detector positions are used to further increase the dimensionality of the received data (alternating between 2 MeV and 14 MeV) such that radial resolving ability can be increased.
- In another embodiment, the neutron detectors are helium-3-filled detectors.
- In another embodiment, the neutron detectors are lithium-6 glass detectors.
- In another embodiment, the source tube is shielded in all but one direction and is manipulated such that it rotates around the tool major axis, such that azimuthal porosity information may be determined through directional bias of the source and/or detectors using neutron moderating or shielding materials.
- In another embodiment, the source tubes and detectors are shielded in all but one direction and are manipulated such that they rotate around the tool major axis, such that azimuthal porosity information may be determined through directional bias of the source and/or detectors using neutron moderating or shielding materials.
- In another embodiment, technique is combined with ultrasound or x-ray density techniques. Radially resolved porosity could be highly advantageous when combined with x-ray, ultrasonic and azimuthal neutron techniques, to map-out (in 3D) the porosity associated with channels or fluid defects in cement surrounding a borehole.
- The foregoing specification is provided only for illustrative purposes, and is not intended to describe all possible aspects of the present invention. While the invention has herein been shown and described in detail with respect to several exemplary embodiments, those of ordinary skill in the art will appreciate that minor changes to the description, and various other modifications, omissions and additions may also be made without departing from the spirit or scope thereof.
Claims (16)
1. A neutron porosity tool having an electronic neutron generator arrangement and a control mechanism used to provide voltage and pulses to an electronic neutron tube so that the output of two neutron reaction planes from collocated target planes in a wellbore environment, said neutron generator arrangement comprising:
at least one vacuum tube;
at least one ion target;
at least one radio-frequency cavity;
at least one high-voltage generator;
at least two neutron detectors;
at least one pulser circuit; and
at least one control circuit.
2. The neutron generator arrangement of claim 1 , wherein the arrangement is configured as to provide two differing ion accelerating voltages by two high voltage generators, such that deuterium-deuterium and deuterium-tritium reactions may be generated within the same reactants plane.
3. The neutron generator arrangement of claim 1 , wherein the arrangement is configured as to provide the same ion accelerating voltages by two high voltage generators, such that deuterium-deuterium reactions are generated on both sides of the target within the same reactants plane.
4. The neutron generator arrangement of claim 1 , wherein the arrangement is configured as to provide the same ion accelerating voltages by two high voltage generators, such that deuterium-tritium reactions are generated on both sides of the target within the same reactants plane.
5. The neutron generator arrangement of claim 1 , wherein the arrangement is configured as to provide two cathode sources and two co-located targets, such that deuterium-deuterium and deuterium-tritium reactions are generated within the same reactants plane.
6. The neutron generator arrangement of claim 1 , wherein two high voltage generators are used to provide differing acceleration voltages on either side of the target, such that deuterium-deuterium and deuterium-tritium reactions are generated within the same reactants plane.
7. The neutron generator arrangement of claim 1 , wherein the pulser circuits are configured to provide pulses to either side of the target concurrently so that deuterium-deuterium and deuterium-tritium reaction outputs are distinct and individual.
8. The neutron generator arrangement of claim 1 , wherein the pulser circuits are configured to provide pulses to either side of the target alternately, such that deuterium-deuterium and deuterium-tritium reaction outputs are distinct and individual.
9. The tool of claim 1 , where the detectors comprise helium-3 gas.
10. The tool of claim 1 , where the detectors comprise Lithium-6 glass.
11. A method of controlling a neutron porosity tool having an electronic neutron generator arrangement and a control mechanism that provides voltage and pulses to an electronic neutron tube thereby enabling the production of two distinct neutron energies to provide radial discrimination of porosity, said method comprising:
controlling a bipolar neutron tube to produce two distinct neutron reactions;
using a control circuit to modify the output of a pulser circuit; and
using a plurality of neutron detectors to determine formation response offsets.
12. The method of claim 11 , further comprising configuring the neutron generator arrangement to provide two differing ion accelerating voltages by two high voltage generators such that deuterium-deuterium and deuterium-tritium reactions may be generated within the same reactants plane.
13. The method of claim 11 , further comprising configuring the arrangement is to provide two cathode sources and two co-located targets such that deuterium-deuterium and deuterium-tritium reactions are generated within the same reactants plane.
14. The method of claim 11 , further comprising controlling two high voltage generators to provide differing acceleration voltages on either side of the target, such that deuterium-deuterium and deuterium-tritium reactions are generated within the same reactants plane.
15. The method of claim 11 , further comprising controlling the pulser circuits so as to provide pulses to either side of the target concurrently, such that deuterium-deuterium and deuterium-tritium reaction outputs are distinct and individual.
16. The method of claim 11 , further comprising configuring the pulser circuits so as to provide pulses to either side of the target alternately, such that deuterium-deuterium and deuterium-tritium reaction outputs are distinct and individual.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17/150,894 US20210132252A1 (en) | 2017-04-20 | 2021-01-15 | Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole |
US18/225,235 US20230375742A1 (en) | 2017-04-20 | 2023-07-24 | Near-Field Sensitivity of Formation and Cement Porosity Measurements With Radial Resolution in a Borehole |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201762487530P | 2017-04-20 | 2017-04-20 | |
US15/958,536 US20180239053A1 (en) | 2017-04-20 | 2018-04-20 | Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole |
US17/150,894 US20210132252A1 (en) | 2017-04-20 | 2021-01-15 | Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/958,536 Continuation US20180239053A1 (en) | 2017-04-20 | 2018-04-20 | Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US18/225,235 Continuation US20230375742A1 (en) | 2017-04-20 | 2023-07-24 | Near-Field Sensitivity of Formation and Cement Porosity Measurements With Radial Resolution in a Borehole |
Publications (1)
Publication Number | Publication Date |
---|---|
US20210132252A1 true US20210132252A1 (en) | 2021-05-06 |
Family
ID=63166526
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/958,536 Abandoned US20180239053A1 (en) | 2017-04-20 | 2018-04-20 | Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole |
US17/150,894 Abandoned US20210132252A1 (en) | 2017-04-20 | 2021-01-15 | Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole |
US18/225,235 Pending US20230375742A1 (en) | 2017-04-20 | 2023-07-24 | Near-Field Sensitivity of Formation and Cement Porosity Measurements With Radial Resolution in a Borehole |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/958,536 Abandoned US20180239053A1 (en) | 2017-04-20 | 2018-04-20 | Near-field sensitivity of formation and cement porosity measurements with radial resolution in a borehole |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US18/225,235 Pending US20230375742A1 (en) | 2017-04-20 | 2023-07-24 | Near-Field Sensitivity of Formation and Cement Porosity Measurements With Radial Resolution in a Borehole |
Country Status (9)
Country | Link |
---|---|
US (3) | US20180239053A1 (en) |
EP (1) | EP3612865A1 (en) |
JP (1) | JP2020517930A (en) |
CN (1) | CN110832357A (en) |
AU (1) | AU2018255410A1 (en) |
BR (1) | BR112019021870A2 (en) |
CA (1) | CA3061020A1 (en) |
MX (1) | MX2019012551A (en) |
WO (1) | WO2018195436A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190187325A1 (en) | 2018-02-14 | 2019-06-20 | Philip Teague | Methods and means for neutron imaging within a borehole |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090045329A1 (en) * | 2007-08-16 | 2009-02-19 | Schlumberger Technology Corporation | Downhole Tools Having Combined D-D and D-T Neutron Generators |
US20100314536A1 (en) * | 2009-06-12 | 2010-12-16 | Baker Hughes Incorporated | Nuclear detectors built directly into shielding or modulating material |
US20120273342A1 (en) * | 2011-04-21 | 2012-11-01 | Regents Of The University Of California | Compact ion accelerator source |
US9472370B2 (en) * | 2013-12-16 | 2016-10-18 | Schlumberger Technology Corporation | Neutron generator having multiple extractors with independently selectable potentials |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL50089C (en) | 1937-01-23 | |||
US3546512A (en) | 1967-02-13 | 1970-12-08 | Schlumberger Technology Corp | Neutron generator including an ion source with a massive ferromagnetic probe electrode and a permanent magnet-electrode |
CA1062813A (en) * | 1975-05-22 | 1979-09-18 | Ronald E. Turcotte | Well logging method and apparatus |
US4996017A (en) | 1982-03-01 | 1991-02-26 | Halliburton Logging Services Inc. | Neutron generator tube |
FR2666477A1 (en) | 1990-08-31 | 1992-03-06 | Sodern | HIGH FLOW NEUTRONIC TUBE. |
NO330708B1 (en) | 2009-10-23 | 2011-06-20 | Latent As | Apparatus and method for controlled downhole production of ionizing radiation without the use of radioactive chemical isotopes |
CN202954810U (en) * | 2012-05-25 | 2013-05-29 | 中国石油天然气集团公司 | Deuterium tritium controllable source neutron porosity logging instrument |
CN202788798U (en) * | 2012-08-20 | 2013-03-13 | 中国石油天然气集团公司 | Underground pulse neutron generator |
MX360670B (en) | 2014-04-28 | 2018-11-13 | Halliburton Energy Services Inc | Downhole evaluation with neutron activation measurement. |
-
2018
- 2018-04-20 US US15/958,536 patent/US20180239053A1/en not_active Abandoned
- 2018-04-20 AU AU2018255410A patent/AU2018255410A1/en not_active Abandoned
- 2018-04-20 CA CA3061020A patent/CA3061020A1/en not_active Abandoned
- 2018-04-20 WO PCT/US2018/028589 patent/WO2018195436A1/en unknown
- 2018-04-20 CN CN201880041476.6A patent/CN110832357A/en active Pending
- 2018-04-20 MX MX2019012551A patent/MX2019012551A/en unknown
- 2018-04-20 EP EP18724030.4A patent/EP3612865A1/en active Pending
- 2018-04-20 BR BR112019021870-0A patent/BR112019021870A2/en not_active IP Right Cessation
- 2018-04-20 JP JP2019556954A patent/JP2020517930A/en active Pending
-
2021
- 2021-01-15 US US17/150,894 patent/US20210132252A1/en not_active Abandoned
-
2023
- 2023-07-24 US US18/225,235 patent/US20230375742A1/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090045329A1 (en) * | 2007-08-16 | 2009-02-19 | Schlumberger Technology Corporation | Downhole Tools Having Combined D-D and D-T Neutron Generators |
US20100314536A1 (en) * | 2009-06-12 | 2010-12-16 | Baker Hughes Incorporated | Nuclear detectors built directly into shielding or modulating material |
US20120273342A1 (en) * | 2011-04-21 | 2012-11-01 | Regents Of The University Of California | Compact ion accelerator source |
US9472370B2 (en) * | 2013-12-16 | 2016-10-18 | Schlumberger Technology Corporation | Neutron generator having multiple extractors with independently selectable potentials |
Also Published As
Publication number | Publication date |
---|---|
CA3061020A1 (en) | 2018-10-25 |
US20230375742A1 (en) | 2023-11-23 |
AU2018255410A1 (en) | 2019-12-05 |
MX2019012551A (en) | 2020-02-12 |
CN110832357A (en) | 2020-02-21 |
WO2018195436A1 (en) | 2018-10-25 |
BR112019021870A2 (en) | 2020-05-26 |
JP2020517930A (en) | 2020-06-18 |
US20180239053A1 (en) | 2018-08-23 |
EP3612865A1 (en) | 2020-02-26 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Akahane et al. | Stretching of slow positron pulses generated with an electron linac | |
US9560734B2 (en) | Dense plasma focus (DPF) accelerated non radio isotopic radiological source | |
US20030223528A1 (en) | Electrostatic accelerated-recirculating-ion fusion neutron/proton source | |
RU2010126076A (en) | NEUTRON GENERATOR | |
US20230375742A1 (en) | Near-Field Sensitivity of Formation and Cement Porosity Measurements With Radial Resolution in a Borehole | |
JP2009210585A (en) | Neutron generator for controlling ion beam and target voltage in neutron generator for improving performance | |
GB2429832A (en) | Neutron generator tube having a high voltage insulator extending in a non-bounding relationship with an accelerating gap | |
US9448327B2 (en) | X-ray generator having multiple extractors with independently selectable potentials | |
US10182491B2 (en) | Deuterium-deuterium neutron generators | |
US4126806A (en) | Intense ion beam producing reflex triode | |
US9472370B2 (en) | Neutron generator having multiple extractors with independently selectable potentials | |
US10455684B2 (en) | Field-ionization neutron generator | |
US8971473B2 (en) | Plasma driven neutron/gamma generator | |
US8279993B2 (en) | Gamma source for active interrogation | |
US2907884A (en) | Compact neutron source | |
Bures et al. | Relationship between neutron yield and macroscale pinch dynamics of a 1.4-kJ plasma focus over hundreds of pulses | |
US20160143123A1 (en) | Method and Apparatus to Identify Functional Issues of a Neutron Radiation Generator | |
WO2014158474A1 (en) | Ion source having negatively biased extractor | |
Yoshikawa et al. | Research and development of landmine detection system by a compact fusion neutron source | |
US5104610A (en) | Device for perfecting an ion source in a neutron tube | |
Kozyrev et al. | Optimal Conditions for the Generation of Runaway Electrons in High-Pressure Gases | |
Lomer et al. | A pulsed neutron source for reactor measurements | |
USRE26254E (en) | Gale ion accelerator | |
Leung et al. | Plasma driven neutron/gamma generator | |
Benker et al. | Pulsed, Intense Electron Beams From Pseudo-Spark Discharges |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STPP | Information on status: patent application and granting procedure in general |
Free format text: APPLICATION DISPATCHED FROM PREEXAM, NOT YET DOCKETED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
AS | Assignment |
Owner name: VISURAY INTECH LTD (BVI), VIRGIN ISLANDS, BRITISH Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TEAGUE, PHILIP;REEL/FRAME:057581/0896 Effective date: 20180525 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |