# US 2024/0201415 A1 · Method and device for calibrating depth of optical fibre in well > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0201415 A1 - Document ID: US20240201415A1 - Status: Published application - Kind: A1 - Application number: 18/287,216 - Filed: 2022-06-30 - Published: 2024-06-20 - Earliest claimed: 2021-12-30 - Assignees: BGP Inc., China National Petroleum Corporation; China National Petroleum Corporation - Applicants: China National Petroleum Corporation; BGP Inc., China National Petroleum Corporation - Inventors: Yanpeng LI; Congwei LIU; Yanbin ZHANG - Web page: https://patentgrep.com/patent/US20240201415A1 ## CPC - G01V 13/00: Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00 - 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 - G01H 9/004: {using fibre optic sensors (light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125)} - G01V 1/226: {Optoseismic systems} - G01V 1/305: {Travel times} - G01V 1/50: Analysing data - G01V 2210/1429: Subsurface, e.g. in borehole or below weathering layer or mud line - G01V 2210/161: Vertical seismic profiling [VSP] - Y02A 90/30: Assessment of water resources - 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 - G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE ## Abstract Disclosed are an improved method and device for calibrating the depth of an optical fibre in a well. The method includes acquiring borehole seismic wave field data based on an optical fibre acoustic wave sensor; determining first arrival time information based on the borehole seismic wave field data; determining a downgoing wave first arrival amplitude based on the first arrival time information and the borehole seismic wave field data; determining an optical fibre amplitude feature point based on the downgoing wave first arrival amplitude; determining a wellhead initial position and a receiving point spacing of the optical fibre in the well based on the optical fibre amplitude feature point and logging curve feature points; and determining depth calibration information of the optical fibre in the well based on the wellhead initial position and the receiving point spacing. ## Claims ### Claim 1 A method for calibrating a depth of an optical fibre in a well, comprising: acquiring borehole seismic wave field data based on an optical fibre acoustic wave sensor; determining first arrival time information based on the borehole seismic wave field data; determining a downgoing wave first arrival amplitude based on the first arrival time information and the borehole seismic wave field data; determining an optical fibre amplitude feature point based on the downgoing wave first arrival amplitude; determining a wellhead initial position and a receiving point spacing of the optical fibre in the well based on the optical fibre amplitude feature point and logging curve feature points; and determining depth calibration information of the optical fibre in the well based on the wellhead initial position and the receiving point spacing. ### Claim 2 (depends on 1) The method according to claim 1, further comprising: before the determining the downgoing wave first arrival amplitude, optimising the borehole seismic wave field data based on a preset filtering algorithm to obtain an optimised downgoing wave field; and determining the downgoing wave first arrival amplitude based on the optimised downgoing wave field and the first arrival time information. ### Claim 3 (depends on 1) The method according to claim 1, wherein the determining the downgoing wave first arrival amplitude based on the first arrival time information and the borehole seismic wave field data comprises: determining a preset short time window based on the first arrival time information; determining specific seismic wave field data within the preset short time window; and determining the downgoing wave first arrival amplitude based on the specific seismic wave field data. ### Claim 4 (depends on 1) The method according to claim 1, wherein determining the optical fibre amplitude feature point based on the downgoing wave first arrival amplitude comprises: performing a spherical spreading amplitude compensation operation on the downgoing wave first arrival amplitude to obtain a compensated amplitude; generating a relative impedance curve based on the compensated amplitude; acquiring preset logging data; and determining the corresponding optical fibre amplitude feature point based on the preset logging data and the relative impedance curve. ### Claim 5 (depends on 1) The method according to claim 1, further comprising: determining a borehole sampling parameter of the optical fibre in the well based on the depth calibration information; performing a depth resampling operation based on the borehole sampling parameter to obtain resampled data; and generating updated depth calibration information based on the resampled data. ### Claim 6 A device for calibrating a depth of an optical fibre in a well, comprising: a seismic wave field data acquisition unit, used for acquiring borehole seismic wave field data based on an optical fibre acoustic wave sensor; a first arrival time determination unit, used for determining first arrival time information based on the borehole seismic wave field data; a downgoing wave first arrival amplitude determination unit, used for determining a downgoing wave first arrival amplitude based on the first arrival time information and the borehole seismic wave field data; a feature point determination unit, used for determining an optical fibre amplitude feature point based on the downgoing wave first arrival amplitude; an optical fibre parameter determination unit, used for determining a wellhead initial position and a receiving point spacing of the optical fibre in the well based on the optical fibre amplitude feature point and logging curve feature points; and a depth calibration unit, used for determining depth calibration information of the optical fibre in the well based on the wellhead initial position and the receiving point spacing. ### Claim 7 (depends on 6) The device according to claim 6, further comprising an optimisation unit, used for: optimising the borehole seismic wave field data based on a preset filtering algorithm to obtain an optimised downgoing wave field; the downgoing wave first arrival amplitude determination unit is further used for determining the downgoing wave first arrival amplitude based on the optimised downgoing wave field and the first arrival time information. ### Claim 8 (depends on 6) The device according to claim 6, wherein the downgoing wave first arrival amplitude determination unit comprises: a time window determination module, used for determining a preset short time window based on the first arrival time information; a data determination module, used for determining specific seismic wave field data within the preset short time window; and a first arrival amplitude determination module, used for determining a downgoing wave first arrival amplitude based on the specific seismic wave field data. ### Claim 9 (depends on 6) The device according to claim 6, wherein the feature point determination unit comprises: a compensation module, used for performing a spherical spreading amplitude compensation operation on the downgoing wave first arrival amplitude to obtain a compensated amplitude; an impedance information generation module, used for generating a relative impedance curve based on the compensated amplitude; a logging data acquisition module, used for acquiring preset logging data; and a feature point generation module, used for determining a corresponding optical fibre amplitude feature point based on the preset logging data and the relative impedance curve. ### Claim 10 (depends on 6) The device according to claim 6, further comprising a resampling unit, used for: determining a borehole sampling parameter of the optical fibre in the well based on the depth calibration information; performing a depth resampling operation based on the borehole sampling parameter to obtain resampled data; and generating updated depth calibration information based on the resampled data. ### Claim 11 (canceled) ### Claim 12 (depends on 1) A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the method for calibrating the depth of an optical fibre in a well according to claim 1.