# US 11,906,692 B2 · Nuclear logging tools and applications thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,692 B2 - Document ID: US11906692B2 - Status: Granted - Kind: B2 - Application number: 17/333,834 - Filed: 2021-05-28 - Published: 2022-08-11 - Granted: 2024-02-20 - Earliest claimed: 2021-02-11 - Assignees: China Petroleum & Chemical Corporation - Applicants: China Petroleum & Chemical Corporation - Inventors: Jeremy Zhang; Sheng Zhan - Web page: https://patentgrep.com/patent/US11906692B2 ## CPC - G01V 5/102: {the neutron source being of the pulsed type} - E21B 47/017: Protecting measuring instruments - E21B 49/00: Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells - G01V 5/045: {Transmitting data to recording or processing apparatus; Recording data} - G01V 5/105: {the neutron source being of the pulsed type} - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A nuclear logging tool has a housing, one or more neutron sources, one or more shields, and two or more detectors disposed about the housing. Each of the one or more neutron sources is configured to generate neutrons in pulses or continuously and each of the two or more detectors is operable to detect neutrons and gamma rays. The two or more detectors include a first detector disposed at a first distance from a first neutron source and a second detector disposed at a second distance from the first neutron source. The first distance is shorter than the second distance. The first distance and the second distance is measured in the longitudinal direction of the housing. Each shield is operable to absorb neutrons and gamma rays and is disposed inside the housing between one of the one or more neutron source and one of the one or more detectors. ## Claims ### Claim 1 A nuclear logging tool, comprising: a housing, two or more neutron sources, one or more shields, and two or more detectors disposed about the housing, wherein the two or more neutron sources include a first neutron source and a second neutron source, each configured to generate neutrons in pulses or continuously and each of the two or more detectors is operable to detect neutrons and gamma rays, wherein the two or more detectors include a first detector disposed at a first distance from a first neutron source and a second detector disposed at a second distance from the first neutron source, wherein the first distance is shorter than the second distance, wherein each of the first distance and the second distance is in a longitudinal direction of the housing, and wherein each shield is operable to absorb neutrons and gamma rays and is disposed inside the housing between one of the two or more neutron sources and one of the two or more detectors, wherein the second neutron source is spaced away from the first neutron source in the longitudinal direction of the housing, and the two or more detectors are disposed between the first neutron source and the second neutron source. ### Claim 2 (depends on 1) The nuclear logging tool of claim 1, wherein each of the two or more neutron sources is independently a Deuterium-Tritium (D-T) neutron generator, a Deuterium-Deuterium (D-D) neutron generator, or a radioisotope neutron source. ### Claim 3 (depends on 1) The nuclear logging tool of claim 1, further comprises a third detector disposed at a third distance from the first neutron source in the longitudinal direction of the housing, and the third distance is larger than the second distance. ### Claim 4 (depends on 1) The nuclear logging tool of claim 1, wherein each of the two or more detectors comprises a scintillator made of Cs2LiYCl6 or Cs2LiLaBr6. ### Claim 5 (depends on 1) The nuclear logging tool of claim 1, wherein the two or more neutron sources include an isotope neutron source and a pulsed neutron generator. ### Claim 6 (depends on 1) The nuclear logging tool of claim 1, wherein at least two of the two or more detectors are installed at different radial directions about the housing and have different toolface angles when the nuclear logging tool is deployed in a subterranean formation. ### Claim 7 (depends on 6) The nuclear logging tool of claim 6, wherein at least one of the two or more detectors is located on an axis or off the axis of the logging tool. ### Claim 8 (depends on 1) The nuclear logging tool of claim 1, wherein the shield is made of a material selected from gadolinium (Gd), samarium (Sm), tungsten borides, an alloy containing Gd, an alloy containing Sm, Gd2O3, Sm2O3, B2O3, and mixtures thereof. ### Claim 9 (depends on 8) The nuclear logging tool of claim 8, wherein a portion of a casing of at least one among the two or more detectors is made of the shield material. ### Claim 10 (depends on 1) A method for measuring subterranean formation properties, comprising: deploying the nuclear logging tool of claim 1 into a subterranean formation; causing the two or more neutron sources to emit neutrons into the subterranean formation; converting neutrons and gamma rays from the subterranean formation received by the two or more detectors to electric signals; and analyzing electric signals to obtain a plurality of formation properties. ### Claim 11 (depends on 10) The method of claim 10, wherein the plurality of formation properties include formation density, formation porosity, gas and oil saturation, and/or formation element concentration. ### Claim 12 (depends on 1) A downhole drilling system, comprising: a drill string having a bottom hole assembly (BHA) disposed at a lower part thereof; a kelly drive configured to deliver the drill string into a borehole; a top drive configured to rotate the drill string; and a controller, wherein the BHA comprises a drill bit disposed at an end portion of the BHA, a downhole motor, and a measurement sub configured to measure subterranean formation properties and operational parameters, wherein the measurement sub comprises the nuclear logging tool of claim 1. ### Claim 13 (depends on 12) The drilling system of claim 12, wherein each of the two or more neutron sources in the nuclear logging tool is independently a Deuterium-Tritium (D-T) neutron generator, a Deuterium-Deuterium (D-D) neutron generator, or a radioisotope neutron source. ### Claim 14 (depends on 1) A wireline logging tool, comprising the nuclear logging tool of claim 1 connected to an electric cable.