CN101581214A - Transient electromagnetic logging device in through-casing well - Google Patents
Transient electromagnetic logging device in through-casing well Download PDFInfo
- Publication number
- CN101581214A CN101581214A CNA2009100216541A CN200910021654A CN101581214A CN 101581214 A CN101581214 A CN 101581214A CN A2009100216541 A CNA2009100216541 A CN A2009100216541A CN 200910021654 A CN200910021654 A CN 200910021654A CN 101581214 A CN101581214 A CN 101581214A
- Authority
- CN
- China
- Prior art keywords
- coil
- transient electromagnetic
- links
- magnetizing
- sleeve pipe
- 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.)
- Granted
Links
Images
Abstract
The invention discloses a transient electromagnetic logging device in a through-casing well, which comprises ground monitoring equipment 1, wherein the ground monitoring equipment 1 is connected with a downhole logging instrument 3 through a cable 2, and the downhole logging instrument 3 consists of a transmitting control unit 4, a receiving control unit 5, a magnetized power supply 6, a magnetizer 7, a transmitting coil 12 and a receiving coil 13. The device utilizes transient electromagnetic technology to transmit low-frequency high-power electromagnetic signals; according to Faraday law of electromagnetic induction, a variable magnetic field produces a variable electric field; the characteristics of an electromagnetic field are determined by the characteristics of medium; and the magnetic field which embodies the characteristics of the detected medium is received by the downhole logging instrument 3, so that the aim of identifying stratum characteristics through the signals detected by the receiving coil is achieved. The device has the characteristics of high efficiency, quickness and non-contact.
Description
Technical field
The invention belongs to a kind of well logging apparatus of resource environment development field, particularly a kind of application of sleeve magnetization technology and transient electromagnetic technology combine the transient electromagnetic well logging apparatus in the cased well of crossing of realizing the producing well stratum detecting.
Background technology
Along with constantly carrying out of production of hydrocarbons process, a large amount of producing wells enter the middle and later periods in succession, moisture content constantly raises, output descends gradually, in order to improve the production capacity in oil field, prolongs oilfield life, increase recoverable reserves, in Oilfield developing, need to determine the dead oil gas area, follow the tracks of the variation of reservoir fluid saturation ratio and the situation of movement of oil reservoir liquid surface, and the variation of following the tracks of fluid saturation in the old oil reservoir need be carried out in producing well.The production well log technology has become deposit dynamic monitoring, remaining oil distribution monitoring, has determined the important technical of the exhausted index of oil gas, has been the focus that the exploitation of petroleum resources middle and later periods is paid close attention to.
Different with open hole well, metal sleeve has been installed in the producing well, because metal sleeve has good electrical conductivity and higher magnetic conductivity, the high-frequency electromagnetic signal of emission is most of in communication process in the sleeve pipe is shielded by metal sleeve, fail to form effective secondary field in the stratum outside the sleeve pipe, so the receiving coil induction is less than the signal that has formation information.The existence of metal sleeve has strengthened the difficulty of electrical log, and the conventional application of induction logging technology in production well log has been subjected to restriction.
Both at home and abroad TCR being measured mainly is by making up a kind of and sleeve pipe electrode in contact system, on each electrode of electrode system, apply certain voltage, and constitute the loop with ground electrodes, solve the electric current that flows into the stratum by the voltage drop of measuring different point-to-point transmissions on the sleeve pipe, and then obtain the resistivity on stratum according to the relation of electric current and voltage, cross sleeve pipe formation resistivity logging instrument, the through casing resistivity logging instrument of the double-channel cased hole formation resistivity logging instrument of Schlumberger company exploitation and the development of Atlas, Bake etc. as the common exploitation of Atlas, west company and natural gas academy.
The subject matter that these through casing resistivity logging methods exist is: in electrode and process that sleeve pipe contacts, can produce thermoelectrical potential, also can make simultaneously electrode system and casing wall produce friction because of the lifting of logger, and generation friction electromotive force, because measured signal mostly is nV level signal, and friction electromotive force and thermoelectrical potential are generally μ V level or higher.In addition, because the electrical conductivity of sleeve pipe itself is than big several orders of magnitude of electrical conductivity on stratum, therefore when the stratum being applied emission electrode with the sleeve pipe electrode in contact, overwhelming majority current drain is on sleeve pipe, have only very little one part of current to flow into the stratum, the corrosion of sleeve pipe in addition, the bonding quality of the outer cement of sleeve pipe, the influence of various factors such as natural potential on stratum itself, make signal to noise ratio very low, useful signal is actually and is submerged in the noise, the well logging difficulty is big, technical sophistication, and the instrument cost is very high, be unfavorable for popularizing, restricted the promotion and application of technology.
Summary of the invention
The objective of the invention is to overcome above-mentioned the deficiencies in the prior art, a kind of transient electromagnetic well logging apparatus in the cased well of crossing is provided, can realize that the identification of the outer stratum of sleeve pipe characteristic is had efficient, quick, non-contacting characteristics.
Technical scheme of the present invention was achieved in that transient electromagnetic well logging apparatus in the cased well, comprised surface-monitoring equipment 1, and surface-monitoring equipment 1 links to each other with downhole logging instrument 3 by cable 2.
Described downhole logging instrument 3 comprises emission controlling unit 4, receive control module 5, excitation supply 6, magnetizing assembly 7, transmitting coil 12 and receiving coil 13, emission controlling unit 4 and transmitting coil 12 link to each other by holding wire, receiving control module 5 and receiving coil 13 links to each other by data wire, excitation supply 6 links to each other with the magnetizing coil 14 of magnetizing assembly 7, magnetizing coil 14 outer wrap cylindrical nonmetal megohmite insulant 15, megohmite insulant 15 all has coil groove 18 up and down, transmitting coil 12 and receiving coil 13 are wrapped on the megohmite insulant 15 by the track of coil groove 18, magnetization iron core 11 is positioned at sleeve pipe 16 centers, vertically is inserted in magnetizing coil 14 inside.
The upper/lower terminal of magnetization iron core 11 is connected with upper magnet yoke 8, lower yoke 10 respectively, constitute the coil rack of whole magnetizing assembly 7, iron brush 9 is positioned at upper magnet yoke 8, lower yoke 10 both sides, one end of iron brush 9 links to each other with upper magnet yoke 8, lower yoke 10 by rotating shaft 17, and the other end of iron brush 9 launches the back and contacts with sleeve pipe 16.
What emission controlling unit 4 was injected in transmitting coil 12 is bipolarity transient electromagnetic pumping signal.
The present invention is magnetized processing near the sleeve pipe the borehole measurement zone 16, make it reach magnetic saturation, reduce its magnetic conductivity, reduce the influence of sleeve pipe to electromagnetic signal, utilize the transient electromagnetic technology, the low-frequency high-power electromagnetic signal of emission passed sleeve pipe 16, according to Faraday's electromagnetic induction law, pass the electric field that the variation magnetic field 16 of sleeve pipe can change, and the characteristic of sleeve pipe 16 external electromagnetic fields is by the decision of the characteristic of medium, the magnetic field of this embodiment measured medium characteristic can be received by downhole logging instrument 3 by sleeve pipe 16 equally, thereby reaches the purpose by the detected signal identification of receiving coil formation characteristics.
Description of drawings
Fig. 1 is a well logging apparatus structural representation of the present invention.
Fig. 2 is the partial structurtes schematic diagram of well logging apparatus of the present invention.
The specific embodiment
Below in conjunction with accompanying drawing structural principle of the present invention and operating principle are described in detail.
With reference to Fig. 1, cross transient electromagnetic well logging apparatus in the cased well, comprise surface-monitoring equipment 1, surface-monitoring equipment 1 links to each other with downhole logging instrument 3 by cable 2, downhole logging instrument 3 comprises emission controlling unit 4, receive control module 5, excitation supply 6, magnetizing assembly 7, transmitting coil 12 and receiving coil 13, emission controlling unit 4 and transmitting coil 12 link to each other by holding wire, receiving control module 5 and receiving coil 13 links to each other by data wire, excitation supply 6 links to each other with the magnetizing coil 14 of magnetizing assembly 7, magnetizing coil 14 outer wrap cylindrical nonmetal megohmite insulant 15, megohmite insulant 15 all has coil groove 18 up and down, transmitting coil 12 and receiving coil 13 are wrapped on the megohmite insulant 15 by the track of coil groove 18, magnetization iron core 11 is positioned at sleeve pipe 16 centers, vertically be inserted in magnetizing coil 14 inside, on the magnetization iron core 11, following two ends by screw thread respectively with upper magnet yoke 8, lower yoke 10 connects, constitute the coil rack of whole magnetizing assembly 7, iron brush 9 is positioned at upper magnet yoke 8, lower yoke 10 both sides, one end of iron brush 9 is by rotating shaft 17 and upper magnet yoke 8, lower yoke 10 links to each other, and the other end of iron brush 9 launches the back and contacts with sleeve pipe 16.
Referring to Fig. 2, magnetizing assembly 7 comprises upper magnet yoke 8, iron brush 9, lower yoke 10, magnetization iron core 11, magnetizing coil 14, rotating shaft 17, magnetization iron core 11 vertically is inserted in magnetizing coil 14 inside, magnetizing coil 14 links to each other with excitation supply 6, the upper/lower terminal of magnetization iron core 11 is connected with upper magnet yoke 8, lower yoke 10 respectively by screw thread, constitute the coil rack of whole magnetizing assembly 7, iron brush 9 is positioned at upper magnet yoke 8, lower yoke 10 both sides, one end of iron brush 9 links to each other with upper magnet yoke 8, lower yoke 10 by rotating shaft 17, and the other end of iron brush 9 launches the back and contacts with sleeve pipe 16.
Operating principle of the present invention is:
(1) magnetizing assembly 7 of startup logging instrument 3, regulating rotating shaft 17 makes iron brush 9 contact with sleeve pipe 16 in the producing well, together with iron core 11, upper magnet yoke 8, lower yoke 10 constitutes closed magnetic loop, in magnetizing coil 14, inject direct current by excitation supply 6, in producing well, produce stabilizing magnetic field, realize near the magnetization of the sleeve pipe search coverage is handled;
(2) start emission controlling unit 4, in transmitting coil 12, inject bipolarity transient electromagnetic pumping signal;
(3) extract by the secondary field response characteristic signal in 13 pairs of investigative ranges of receiving coil;
(4) to the signal that collects on the receiving coil 13 amplify, filtering, sampling, finish processing by dsp system to information extraction.
(5) will handle the back result and upload ground monitoring system 1, draw log, the earth formation of wellbore will be judged by software.
Claims (3)
1, cross transient electromagnetic well logging apparatus in the cased well, comprise surface-monitoring equipment (1), surface-monitoring equipment (1) links to each other with downhole logging instrument (3) by cable (2), it is characterized in that, described downhole logging instrument (3) comprises emission controlling unit (4), receive control module (5), excitation supply (6), magnetizing assembly (7), transmitting coil (12) and receiving coil (13), emission controlling unit (4) links to each other by holding wire with transmitting coil (12), receiving control module (5) links to each other by data wire with receiving coil (13), excitation supply (6) links to each other with the magnetizing coil (14) of magnetizing assembly (7), magnetizing coil (14) outer wrap cylindrical nonmetal megohmite insulant (15), megohmite insulant (15) all has coil groove (18) up and down, transmitting coil (12) and receiving coil (13) are wrapped on the megohmite insulant (15) by the track of coil groove (18), magnetization iron core (11) is positioned at sleeve pipe (16) center, vertically is inserted in magnetizing coil (14) inside.
2, transient electromagnetic well logging apparatus in the cased well excessively according to claim 1, it is characterized in that, the upper/lower terminal of magnetization iron core (11) is connected with upper magnet yoke (8), lower yoke (10) respectively, constitute the coil rack of whole magnetizing assembly (7), iron brush (9) is positioned at upper magnet yoke (8), lower yoke (10) both sides, one end of iron brush (9) links to each other with upper magnet yoke (8), lower yoke (10) by rotating shaft (17), and the other end of iron brush (9) launches the back and contacts with sleeve pipe (16).
3, transient electromagnetic well logging apparatus in the cased well excessively according to claim 1 and 2 is characterized in that what emission controlling unit (4) was injected is bipolarity transient electromagnetic pumping signal in transmitting coil (12).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100216541A CN101581214B (en) | 2009-03-23 | 2009-03-23 | Transient electromagnetic logging device in through-casing well |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100216541A CN101581214B (en) | 2009-03-23 | 2009-03-23 | Transient electromagnetic logging device in through-casing well |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101581214A true CN101581214A (en) | 2009-11-18 |
| CN101581214B CN101581214B (en) | 2012-07-11 |
Family
ID=41363517
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009100216541A Expired - Fee Related CN101581214B (en) | 2009-03-23 | 2009-03-23 | Transient electromagnetic logging device in through-casing well |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101581214B (en) |
Cited By (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102375024A (en) * | 2011-09-14 | 2012-03-14 | 西安石油大学 | Device and method for measuring phase fraction of two-phase fraction |
| WO2012109845A1 (en) * | 2011-02-17 | 2012-08-23 | 长江大学 | Downhole high-power electromagnetic pulse emission apparatus |
| CN102882562A (en) * | 2012-08-22 | 2013-01-16 | 西安交通大学 | Directional-magnetic-path-based high-signal-to-noise-ratio non-contact signal transmitting system |
| CN102966349A (en) * | 2012-11-28 | 2013-03-13 | 褚万泉 | System and method for monitoring cross-hole electromagnetic transient |
| CN103195416A (en) * | 2013-03-29 | 2013-07-10 | 西安石油大学 | Production well resistivity logging device |
| CN103352690A (en) * | 2013-06-25 | 2013-10-16 | 天津大学 | Transient electromagnetic logging transmitting probe |
| CN103352694A (en) * | 2013-06-25 | 2013-10-16 | 天津大学 | Logging instrument with acoustoelectric combination |
| CN103472490A (en) * | 2013-09-05 | 2013-12-25 | 中煤科工集团西安研究院 | Mining intrinsic safety type transient electromagnetic instrument receiving antenna |
| CN103590809A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic well logging excitation method |
| CN103590820A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic emission probe |
| CN103590825A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic well-logging probe detection system |
| CN103603650A (en) * | 2013-10-27 | 2014-02-26 | 中国石油化工集团公司 | Transient electromagnetic logging instrument |
| CN103867183A (en) * | 2012-12-18 | 2014-06-18 | 中国石油化工股份有限公司 | Transient electromagnetic method through casing water exploration tester |
| CN105626059A (en) * | 2015-12-30 | 2016-06-01 | 天津大学 | System and method for carrying out well logging by utilizing transient electromagnetic simulation signal |
| CN108594313A (en) * | 2018-06-05 | 2018-09-28 | 中煤科工集团西安研究院有限公司 | Hand propelled time domain electromagnetic well logging apparatus and method in a kind of coal mine down-hole drilling |
| CN109424358A (en) * | 2017-08-24 | 2019-03-05 | 中国石油化工股份有限公司 | High-power resistivity logging while drilling sender unit |
| CN110593867A (en) * | 2019-10-08 | 2019-12-20 | 西安石油大学 | Method and system for monitoring displacement front of cased reservoir based on transient electromagnetic method and computer storage medium |
| CN112112624A (en) * | 2020-08-21 | 2020-12-22 | 中煤科工集团西安研究院有限公司 | Coal mine underground multi-parameter drilling geophysical prospecting fine remote detection device and method |
| CN113006782A (en) * | 2021-03-31 | 2021-06-22 | 西安石油大学 | Half-coil array induction logging device |
| CN113818818A (en) * | 2021-09-22 | 2021-12-21 | 成都多贝石油工程技术有限公司 | Drilling tool wire passing assembly and application thereof |
| CN114396258A (en) * | 2022-01-18 | 2022-04-26 | 中海油田服务股份有限公司 | Logging-while-drilling instrument |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107575220B (en) * | 2017-09-23 | 2020-11-27 | 天津大学 | Through-casing formation differential resistivity logging method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4849699A (en) * | 1987-06-08 | 1989-07-18 | Mpi, Inc. | Extended range, pulsed induction logging tool and method of use |
| CN2779064Y (en) * | 2005-04-28 | 2006-05-10 | 大庆油田有限责任公司 | Impulse mutual inductance type coupling detector |
| CN101315027B (en) * | 2008-06-25 | 2011-11-16 | 中国海洋石油总公司 | Apparatus for detecting transmitted signal of electromagnetic wave logging instrument |
| CN101349151B (en) * | 2008-08-13 | 2012-04-18 | 中国海洋石油总公司 | Three-stage graduation apparatus of electromagnetic wave logger |
-
2009
- 2009-03-23 CN CN2009100216541A patent/CN101581214B/en not_active Expired - Fee Related
Cited By (30)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012109845A1 (en) * | 2011-02-17 | 2012-08-23 | 长江大学 | Downhole high-power electromagnetic pulse emission apparatus |
| CN102375024A (en) * | 2011-09-14 | 2012-03-14 | 西安石油大学 | Device and method for measuring phase fraction of two-phase fraction |
| CN102882562A (en) * | 2012-08-22 | 2013-01-16 | 西安交通大学 | Directional-magnetic-path-based high-signal-to-noise-ratio non-contact signal transmitting system |
| CN102966349A (en) * | 2012-11-28 | 2013-03-13 | 褚万泉 | System and method for monitoring cross-hole electromagnetic transient |
| CN103867183A (en) * | 2012-12-18 | 2014-06-18 | 中国石油化工股份有限公司 | Transient electromagnetic method through casing water exploration tester |
| CN103195416A (en) * | 2013-03-29 | 2013-07-10 | 西安石油大学 | Production well resistivity logging device |
| CN103195416B (en) * | 2013-03-29 | 2016-03-02 | 西安石油大学 | A kind of producing well resistivity logging device |
| CN103352690A (en) * | 2013-06-25 | 2013-10-16 | 天津大学 | Transient electromagnetic logging transmitting probe |
| CN103352694A (en) * | 2013-06-25 | 2013-10-16 | 天津大学 | Logging instrument with acoustoelectric combination |
| CN103352694B (en) * | 2013-06-25 | 2016-06-08 | 天津大学 | A kind of acoustic-electric combination well detecting Instrument |
| CN103352690B (en) * | 2013-06-25 | 2016-04-06 | 天津大学 | A kind of transient electromagnetic well logging transmitting probe |
| CN103472490A (en) * | 2013-09-05 | 2013-12-25 | 中煤科工集团西安研究院 | Mining intrinsic safety type transient electromagnetic instrument receiving antenna |
| CN103590825A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic well-logging probe detection system |
| CN103590820A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic emission probe |
| CN103590809A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic well logging excitation method |
| CN103603650A (en) * | 2013-10-27 | 2014-02-26 | 中国石油化工集团公司 | Transient electromagnetic logging instrument |
| CN105626059A (en) * | 2015-12-30 | 2016-06-01 | 天津大学 | System and method for carrying out well logging by utilizing transient electromagnetic simulation signal |
| CN105626059B (en) * | 2015-12-30 | 2019-05-03 | 天津大学 | A kind of system and method logged well using transient electromagnetic analog signal |
| CN109424358A (en) * | 2017-08-24 | 2019-03-05 | 中国石油化工股份有限公司 | High-power resistivity logging while drilling sender unit |
| CN108594313A (en) * | 2018-06-05 | 2018-09-28 | 中煤科工集团西安研究院有限公司 | Hand propelled time domain electromagnetic well logging apparatus and method in a kind of coal mine down-hole drilling |
| CN110593867A (en) * | 2019-10-08 | 2019-12-20 | 西安石油大学 | Method and system for monitoring displacement front of cased reservoir based on transient electromagnetic method and computer storage medium |
| CN110593867B (en) * | 2019-10-08 | 2022-10-14 | 西安石油大学 | Method and system for monitoring displacement front of cased reservoir based on transient electromagnetic method and computer storage medium |
| CN112112624A (en) * | 2020-08-21 | 2020-12-22 | 中煤科工集团西安研究院有限公司 | Coal mine underground multi-parameter drilling geophysical prospecting fine remote detection device and method |
| CN112112624B (en) * | 2020-08-21 | 2023-08-25 | 中煤科工集团西安研究院有限公司 | Fine and remote detection device and method for multi-parameter drilling geophysical prospecting under coal mine |
| CN113006782A (en) * | 2021-03-31 | 2021-06-22 | 西安石油大学 | Half-coil array induction logging device |
| CN113006782B (en) * | 2021-03-31 | 2024-02-02 | 西安石油大学 | Half-coil array induction logging device |
| CN113818818A (en) * | 2021-09-22 | 2021-12-21 | 成都多贝石油工程技术有限公司 | Drilling tool wire passing assembly and application thereof |
| CN113818818B (en) * | 2021-09-22 | 2024-03-26 | 北京六合伟业科技股份有限公司 | Drilling tool wire passing assembly and application thereof |
| CN114396258A (en) * | 2022-01-18 | 2022-04-26 | 中海油田服务股份有限公司 | Logging-while-drilling instrument |
| CN114396258B (en) * | 2022-01-18 | 2023-06-23 | 中海油田服务股份有限公司 | Logging while drilling instrument |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101581214B (en) | 2012-07-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101581214B (en) | Transient electromagnetic logging device in through-casing well | |
| CN106246167B (en) | The wireless short pass method and device of nearly drill bit invariable power | |
| CN102147484B (en) | High-power downhole electromagnetic pulse transmission device | |
| US6445307B1 (en) | Drill string telemetry | |
| CN103603650A (en) | Transient electromagnetic logging instrument | |
| AU2009341600B2 (en) | Gasket for inductive coupling between wired drill pipe | |
| CN203640727U (en) | Transient electromagnetic well-logging instrument | |
| CN102767363B (en) | Electric communication drill rod and method for increasing transmission distance of electromagnetic wave measurement while drilling signal | |
| CN102536204A (en) | Method for increasing transmitting efficiency of electromagnetic wave wireless measurement-while-drilling system by aid of multiple insulation short pieces | |
| CN103590809A (en) | Transient electromagnetic well logging excitation method | |
| CN102937022A (en) | System, device and method for transmitting near-bit drilling signals | |
| US10648324B2 (en) | Auxiliary system for use in drilling | |
| CN201448107U (en) | Downhole device of sensing logging instrument | |
| CN103498667A (en) | Downhole parameter transmitting system for shaft producing well | |
| CN204552733U (en) | The circumferential array sensor drive driving circuit of the dynamic full water gaging of a kind of horizontal well | |
| CN107605475A (en) | Equipment, system and method for formation testing | |
| CN201539248U (en) | Electromagnetic logging instrument for oilfield production well | |
| CN115680632B (en) | Underground micro-current signal wireless uploading method and device | |
| CN102094645A (en) | Small-bore microspherically-focused logging instrument | |
| CN103775076B (en) | Magnetic susceptibility checkout gear | |
| CN102865069B (en) | Micro-column type focused logging instrument and micro-column type focused logging method thereof | |
| CN203640726U (en) | Transient electromagnetic emission probe | |
| CN103195416B (en) | A kind of producing well resistivity logging device | |
| CN202755968U (en) | Electromagnetic induction signal coupler | |
| CN114216840B (en) | Distributed casing corrosion real-time monitoring system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120711 Termination date: 20180323 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |