Corrode the device and method of on-line real time monitoring for down-hole string
Technical field
It is more particularly to a kind of for the online of tube and casing in downhole corrosion the invention belongs to oil gas field corrosion monitoring technology field
The probe that monitors in real time, device and method, it is adaptable to which any blending agent of Oil, Water, Gas is high-precision in Temperature Deep hyperbaric environment
Spend the assessment of on-line corrosion monitoring and anticorrosive measure.
Background technology
With oil gas field CO2The large-scale promotion of the tertiary oil recovery technologies such as displacement, by CO2The deep-well oil jacket that the displacement of reservoir oil is brought
Pipe etching problem is on the rise, therefore underground on-line corrosion monitoring has drawn as an important process of oil gas field safe working
The great attention of numerous oil and gas production enterprises is played.
At present, conventional tube and casing in downhole corrosion monitoring carries out corrosion prison by the way of corrosion coupon based on weight-loss method
Survey.A kind of downhole well corrosion monitoring scheme is disclosed in such as Chinese patent literature of Application No. 201220476848.8, it includes
Multiple interior link groups on step in annular in inner body wall, the interior step, it is by an interior insulation shading ring and one
Link composition is monitored, the whole link device can monitor oil pipe simultaneously and corrode with oil sets annular space.But, this common weightlessness
Corrosion evaluation method time and effort consuming, and lacing film must be taken out from underground and could evaluate etch state, it is impossible to it is real-time to reflect
The change of downhole corrosion state.
In order to overcome the defect of said apparatus, in the prior art occur in that and a kind of to be monitored in real time using resistance probe
Scheme.Corroded online using resistance probe technology progress oil-gas pipeline for example, patent document CN 101846644B disclose one kind
The scheme of monitoring, it includes Resistance probe, is provided with the Resistance probe as the built-in sensing element of reference resistance and conduct
Measured resistance is simultaneously directly exposed to the exposed sensing element in pipeline corrosion environment, wherein built-in sensing element and exposed sensitivity
Element is made using identical material.During measurement, by synchronizing differential voltage to built-in sensing element and exposed sensing element
Sampling, calculates the resistance ratio for obtaining two elements.The program is increased using the sectional area of wire or piece because corrosion reduces resistance value
Big characteristic, the change of sectional area is calculated by measuring its resistance delta, and then obtains metal corrosion and corrosion rate, can
With suitable for including various working environments such as gas phase, liquid phase, solid phase and flow particles.
But, because the realization principle of resistance probe is to be based on Ohm's law, it corrodes, and resolution ratio is relatively low, and the program is more suitable
Together in the monitoring of long-term corrosion, and fast erosion monitoring is not suitable for it, particularly underground hot environment can cause microresistivity survey
Precision is reduced.
The content of the invention
For the defect or Improvement requirement of prior art, it is used for down-hole string on-line corrosion monitoring the invention provides one kind
Apparatus and method, it is by resistance probe and AC impedance probe, and the matching of both optimization designs and integrated, so as to realize
The quick on-line monitoring of the corrosion rate of underground oil-gas casing or tubing string, may be used on Oil, Water, Gas in the high temperature and high pressure environment of underground
In the environment of any blending agent.
According to one aspect of the present invention there is provided a kind of combined probe for down-hole string on-line corrosion monitoring, it is special
Levy and be, including:
Probe body, it is sleeved in barrel-type casing, and in sealing contact with the inner walls face, and housing exterior walls are rotten with underground
Lose environment contact;
Resistance probe, it includes being sealingly disposed in reference element in probe body and outside probe body and is exposed to
Primary element in downhole corrosion environment, the reference element and the primary element positioned at probe body are serially connected and and downhole tubular
Post material is identical;And
AC impedance probe, it includes reference electrode, working electrode and auxiliary electrode, and forms the electrode body of electrochemistry three
System, three electrodes are both exposed to corrosive environment, and the material of wherein working electrode is identical with down-hole string;
By gathering the reference element of the resistance probe and the terminal voltage of the primary element, the primary element is obtained
With the resistance ratio of reference element, and then the corrosion allowance of down-hole string is calculated;By being loaded not on the working electrode
With the sine wave signal of frequency, and the polarization current and the polarization potential of reference electrode of synchronous acquisition auxiliary electrode, calculate accordingly
Go out the impedance value of corresponding frequency, obtain the polarization resistance of working electrode, and then corrosion rate can be measured.
As the improvement of the present invention, the sine wave signals of the different frequent points of the loading include high frequency (100Hz~
1000Hz) sine wave signal and low frequency (0.001Hz~0.01Hz) sine wave signal.
As the improvement of the present invention, it is provided with the outer peripheral face that the probe body is contacted with barrel-type casing inwall multiple recessed
Groove, for housing sealing ring, will pop one's head in the one end contacted with corrosive environment with the other end and seals isolation.
As the improvement of the present invention, one end end contacted in barrel-type casing with corrosive environment is connected with a taper sheath,
The taper jacket surface is provided with multiple apertures, for ensure corrosive medium be freely accessible in barrel-type casing and with resistance probe and friendship
Flow impedance probe is contacted.
As the improvement of the present invention, the relative other end of the barrel-type casing is provided with the nut of central opening, for sealing
Close the barrel-type casing upper end and so that cable may pass through.
As the improvement of the present invention, pcb board is provided with the probe body, is integrated with is gone forward side by side for gathering signal thereon
The circuit of row processing.
It is another aspect of this invention to provide that providing a kind of device for down-hole string on-line corrosion monitoring, it includes
The combined probe stated, and bottom are arranged on the pcb board in the probe body of the combined probe, it is characterised in that the PCB plates
On be provided with waveform generator, potentiostatic circuit, single-chip microcomputer, multi-channel a/d converter and bidirectional constant source, wherein,
The single-chip microcomputer is connected with the potentiostatic circuit and multi-channel a/d converter respectively, and the bidirectional constant source leads to
Cross reference element and primary element head and end that wire is connected to series connection, for maintain flow through resistance probe primary element and
The electric current of reference element is constant, the reference electrode and work electricity of the potentiostatic circuit two ends respectively with the AC impedance probe
Pole is connected, the AC signal of the different frequency of waveform generator output by the potentiostatic circuit be loaded onto reference electrode and
Between working electrode,
The multi-channel a/d converter is respectively connecting to primary element two ends and the reference of resistance probe by four ports
The two ends of element, sampling is synchronized for flowing through the terminal voltage difference after both to constant current, and by wire with exchanging resistance
Reference electrode, working electrode and the auxiliary electrode connection of anti-probe, exchanging between working electrode (WE) and reference electrode (RE)
Voltage (UAC) and auxiliary electrode (CE) output ac current signal (IAC) analog-to-digital conversion is carried out by multi-channel a/d converter,
Data input after the above-mentioned synchronous voltage difference used and analog-to-digital conversion is handled to the single-chip microcomputer, obtains described respectively
The resistance ratio of primary element and reference element, and alternating voltage UACWith ac current signal IACBetween Amplitude Ration and phase
Potential difference, etching extent is obtained from there through the resistance ratio, and the impedance of WE under different frequency is obtained by the Amplitude Ration and phase difference
Compose and obtain corrosion rate.
As the improvement of the present invention, the device also includes power regulator and well head power supply, wherein the power regulator
Built-in DC-DC conversion chips and linear voltage stabilization chip, the voltage step-down that well head power supply can be provided to corresponding DC voltage, and
Powered by all circuits after linear voltage stabilization chip voltage stabilizing for pcb board.
As the improvement of the present invention, the device also includes the data collector installed in well head, is provided with transceiver in it,
And electrically connected with the PCB of underground, the corrosion Surveillance center for the data of measurement to be sent to distal end, realize prison in real time
Control.
The above-mentioned device for down-hole string on-line corrosion monitoring is utilized to well there is provided a kind of according to another aspect of the invention
The method that lower tubular column carries out etching extent and corrosion rate real time on-line monitoring, comprises the following steps:
The combined probe is fixed on the outside of tubing string to be monitored and sent into downhole corrosion environment, and is caused therein
Three electrodes of primary element and AC impedance probe in resistance probe are exposed in corrosive environment;
Constant current is passed to the resistance probe, and then gathers the reference element and the voltage at primary element two ends
Difference, obtains the resistance ratio of the primary element and reference element, and then obtain down-hole string etching extent according to Ohm's law;
Sine wave signal to loading different frequent points on the working electrode, and the polarization current of synchronous acquisition auxiliary electrode
With the polarization potential of reference electrode, the impedance value of corresponding frequency is calculated accordingly, and then obtain the polarization resistance Zp of working electrode
And instantaneous corrosion rate.
The present invention can be used for carrying out on-line corrosion monitoring, base to the metal tubing string in the Oil, Water, Gas medium of HTHP underground
In well head data collector and monitoring center software, the remote on-line monitoring of downhole corrosion is realized.Due to the high temperature under Oil/gas Well
Hyperbaric environment, downhole well corrosion monitoring sensor needs to be operated in 130 DEG C of temperature highest, pressure 50MPa corrosive atmosphere.Well
Lower corrosion monitoring sensor is installed in oil pipe, and the data that sensor is gathered pass through the armour that is fixed on oil jacket pipe outer wall clip
Dress cable uploads to the data collector on ground, then by wirelessly or non-wirelessly communication modes, uploads to central monitoring system, makes
User is home-confined can to understand downhole corrosion state at any time, and anticorrosive measure is regulated and controled in time, it is ensured that the safety of Oil/gas Well production
Property and economy.
The present invention uses the integrated corrosion monitoring scheme of resistance probe and AC impedance, wherein, the corruption based on AC impedance
Erosion monitoring method can quickly reflect tubing string in conducting medium instantaneous corrosion rate change, and resistance probe can then reflect gas,
Corrode the change of cumulant in liquid two-phase environment.By instantaneous corrosion rate and corrode cumulant combination, can reflect due to
Corrosion rate quickly changes caused by fluid media (medium) condition changes, and can also reflect the overall corrosion of metal material in a long time
Trend.
The total etching extent and corrosion rate of down-hole string in device energy sensitive detection gas phase or liquid phase environment in the present invention
Change, its etching extent measurement accuracy is up to the 1/5000 of the resistance probe primary element life-span, and AC impedance probe is using sinusoidal
Wave excitation and correlation analysis algorithm, with stronger antijamming capability, and measurement process is rapid, and data reappearance is good, its wink
When corrosion rate Measurement Resolution up to 0.01 μm/a, can quickly reflect the change of downhole corrosion environment.Available for monitoring on-line
The corrosion rate of oil gas casing or tubing string in producing well, the production without interrupting the well.Specifically, the present invention is compared to existing
There is technology to have the following advantages that:
(1) sensitivity of corrosion rate measurement and the reappearance of measurement result are significantly improved based on ac impedance technology,
Than the change that existing method can more quickly reflect etch state;
(2) integrated based on resistance probe and AC impedance probe, the present invention can monitor HTHP air-liquid Holes of Complicated Wells
The etching extent and instantaneous corrosion rate of tubing string in lower environment, compared with prior art can more rapidly accurate evaluation underground anti-corrosion erosion measure
Validity;
(3) the real-time monitoring of down-hole string etch state can be achieved, underground can be understood at any time by manager is stayed indoors
Etch state;
Brief description of the drawings
Fig. 1 is the circuit theory schematic diagram according to the downhole well corrosion monitoring device constructed by the embodiment of the present invention;
Fig. 2 is the combined probe structural representation according to the downhole well corrosion monitoring device constructed by the embodiment of the present invention;
Fig. 3 is according to the downhole well corrosion monitoring apparatus structure schematic diagram constructed by the embodiment of the present invention;
Fig. 4 is according to the downhole well corrosion monitoring device scheme of installation constructed by the embodiment of the present invention;
Fig. 5 is the resistance probe primary element etching extent according to the downhole well corrosion monitoring device constructed by the embodiment of the present invention
Versus time curve figure, wherein, transverse axis is the testing time, and the longitudinal axis is the corrosion allowance of primary element;
Fig. 6 is the AC impedance probe face electrode wink according to the downhole well corrosion monitoring device constructed by the embodiment of the present invention
When corrosion rate versus time curve figure, wherein, transverse axis is the testing time, and the longitudinal axis is instantaneous corrosion rate;
In all of the figs, identical reference is used for representing identical element or structure, wherein:1:Waveform occurs
Device, 2:Real-time clock, 3:Flash storage chip, 4:Potentiostat circuit, 5:Single-chip microcomputer, 6:Communication interface, 7:Multichannel A/
D converters, 8:Bidirectional constant source, 9:Power regulator, 10:Well head power supply, 11:Corrosion monitoring combined probe, 20:8~10 cores
Wire harness, 21:Polytetrafluoroethylene (PTFE) annular groove and sealing ring, 22:Polyether-ether-ketone or polytetrafluoroethylene (PTFE) casting probe body, 23,27:Point
Not Wei resistance probe reference element and primary element, 24,25,26:Respectively the reference electrode of AC impedance probe, work are electric
Pole and auxiliary electrode, 30:High strength stainless steel seal head, 31:High strength stainless steel circular cylindrical shell, 32:PCB, 33:Corrosion is situated between
Mass transter through hole, 34:Stainless steel taper sheath, 40:Well head data collector, 41:Stainless steel armored cable, 42:Downhole corrosion
Monitoring device, 43:Oil pipe, 44:Sleeve pipe, 45:Oil pipe clip.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
Referring to Fig. 1, the downhole well corrosion monitoring device constructed by the embodiment of the present invention includes underground on-line corrosion monitoring device,
Such as accompanying drawing 1, including waveform generator 1, real-time clock 2, data storage 3, potentiostatic circuit 4, single-chip microcomputer 5, communication interface 6,
Multi-channel a/d converter 7, bidirectional constant source 8, power regulator 9, well head power supply 10 and combined monitoring probe 11.
Wherein, waveform generator 1, real-time clock 2, data storage 3, potentiostatic circuit 4, single-chip microcomputer 5, communication interface 6,
Multi-channel a/d converter 7, bidirectional constant source 8, power regulator 9 are arranged in PCB 32.
Such as Fig. 2, combined probe includes probe body 22, resistance probe and AC impedance probe.Wherein, probe body is set with
In barrel-type casing 31, and it is in sealing contact with the internal face of housing 31, and the one end of housing 31 is contacted with corrosive environment.Resistance probe bag
Include the reference element 23 that is sealingly disposed in probe body 22 and outer and in downhole corrosion environment positioned at probe body 22
Primary element 27, the reference element 23 and the primary element 27 in probe body 22n are serially connected and primary element 27
It is identical with down-hole string material.AC impedance probe includes reference electrode 24, working electrode 25 and auxiliary electrode 26, and forms electricity
Chemical three-electrode system, three electrodes are both exposed to corrosive environment, and wherein working electrode WE 25 material is identical with down-hole string;
Such as Fig. 3, pcb board 32 and combined monitoring probe 11 are arranged on the high strength stainless steel in pressure-resistant 50MPa, 150 DEG C of heatproof
In cylindrical shell 31, the two is realized by 8~10 cored wire beams 20 (referring to Fig. 2) and electrically connected.
There are a high temperature modification C8051F single-chip microcomputers 5, preferably 8 or 32 high temperature modification single-chip microcomputers 5 on pcb board 32.The monolithic
Machine 5 connects waveform generator 1, real-time clock 2,64k~512k bytes data storages 3, potentiostatic circuit 4, RS485 respectively
Communication interface 6, multichannel 16bit~24bit A/D converters 7 (such as 16 or 24 100k Hz A/D converters of multichannel
Chip) and power regulator 9.Above-mentioned all chips are powered by 3.3V~5V power regulators 9, and all chips are welded on
On above-mentioned PCB, pcb board is connected on corrosion monitoring combined probe 11 by 8 wires, such as accompanying drawing 2.
Waveform generator 1 is preferably built by 16bit D/A converters and operational amplifier, can be exported and be prestored in single-chip microcomputer 5
The sine wave table of storage.Under clock pulses control, the sine wave signal of specific frequency is inputted into potentiostatic circuit 4, and be loaded into
It is then auxiliary by the two-way A/D Channel Synchronous collection in multi-channel a/d converter 7 on working electrode 25 in AC impedance probe
The polarization current of electrode 26 and the polarization potential of reference electrode 24 are helped, finally alternating voltage and current signal are carried out by single-chip microcomputer
Correlation analysis, and calculate the impedance value of corresponding frequency.Single-chip microcomputer measures high frequency (100~1000Hz) and low frequency (0.001 respectively
~0.01Hz) AC impedance Z under two frequency binshAnd Zl, and then calculate polarization resistance the Zp (=Z of working electrode 25l-Zh)。
Then according to Stern formula, corrosion electric current density Icorr, Icorr=B/Zp (mA/cm are calculated2), and instantaneous corrosion speed
Rate Vcorr, Vcorr=Icorr × 11.74mm/a.Wherein B is Stern coefficients, and value is 26mV~52mV.
Real-time clock 2 is preferred to use PCA8565 clock chips, exportable pulse signal, for by single-chip microcomputer 5 from low-power consumption
It is middle to wake up.
Data storage 6 is preferred to use 32k~256k bytes flash storages, for storing time of measuring, polarization
Resistance ZpAnd etch rate data.
Communication interface 8 is preferred to use the chip of isolated form 485, for instructing and measurement data transmission.
Combined probe includes 8 cores and draws wire harness (A, B, C, D, E, F, G, H) 20, is connected respectively to resistance probe and exchanges resistance
On anti-probe.The sensing element of resistance probe has identical by being made with down-hole string identical material with down-hole string
Etching characteristic, its outward appearance can be thread or laminar or cylindrical shape.Resistance probe (is designated as R by reference elementf) 23 and impression
Element (is designated as Rx) 27 two parts composition, wherein reference element 23 is sealed in probe inside, not corroded, and primary element 27 is then
Exposed to downhole corrosion environment, occurs same corrosion behavior with down-hole string.AC impedance probe (is designated as by reference electrode
RE) 24, working electrode (being designated as WE) 25 and auxiliary electrode (being designated as CE) 26 are constituted, and constitute electrochemistry three-electrode system.Three electrodes
Outward appearance can be cylindric or annular shape, and be both exposed to corrosive environment.WE 25 material and down-hole string phase in three electrodes
Together, and RE 24 can be high purity zinc or MnO2Or Ag/AgCl powder die mould electrodes, CE 26 can be then stainless steel or titanium alloy
Material.Probe body 22 is cylinder, using polyether-ether-ketone (PEEK) or polytetrafluoroethylene (PTFE) (PTFE) integral cast, and probe is originally
Body 22 is installed in high-strength stainless steel circular cylindrical shell 31.There are 2~3 annular grooves on the outside of probe body, for installing
PTFE seal circle 21, to improve the sealability between probe body 22 and high strength stainless steel circular cylindrical shell 31.
The other two-way A/D of multi-channel a/d converter 7 in Fig. 1 is respectively connecting to the electricity of combined probe 11 by wire harness
Hinder the two ends of tip reference element 23 and primary element 27 (referring to Fig. 2).Reference element 23 be embedded in fire resistant resin and with
External environment is isolated;Primary element 27 is exposed in corrosive environment, and the two is made by U-shaped wire or thin plate;And resistance value
It is preferred that 5 between 50m Ω.Bidirectional constant source 8 is connected with two terminal As of resistance probe, F inputs, the constant-current source
0.1A~the 0.5A for exporting alternate change direction is controlled to encourage constant current using high-precision power managing chip, and by single-chip microcomputer 5,
Voltage drop is formed when electric current is by reference to element 23 and primary element 27, by multi-channel a/d converter 7 and its preposition 64 times
~128 times of gain amplifiers measure the voltage drop on reference element 23 and primary element 27 simultaneously, finally calculate it by single-chip microcomputer 5
Voltage drop ratio, and be converted into according to Ohm's law total etching extent of primary element.Corrosion monitoring combined probe 11 also leads to
Cross wire and be connected to reference electrode 24, working electrode 25 and auxiliary electrode 26 exposed to corrosive environment, these electrodes can be justified
Column or annular shape, wherein reference electrode 24 preferably can be by high purity zinc or MnO2Or Ag/AgCl powder die mould electrodes are made, work
Electrode 25 with down-hole string identical material then preferably by being made, and auxiliary electrode 26 is then preferably made by stainless steel or titanium alloy.
Resistance probe is connected to bidirectional constant source 8 by two lead terminals (A, H) drawn in wire harness 20, for maintaining
Constant current flows through the primary element 27 and reference element 23 of resistance probe, power amplifier and relay built in constant current supply 8
Device, exportable 100~500mA constant current, the sense of current is then by Control, and power amplifier and relay are by single-chip microcomputer
5 instruction control.Multi-channel a/d converter 7 is the A/D of 16~24, sigma-delta type, using 4 passage Differential Inputs, by drawing
B, F and F, G lead terminals in wire harness 20 are connected to the primary element 27 of resistance probe and the two ends of reference element 23, and to two
Terminal voltage difference on individual element synchronizes sampling.To improve precision, measurement process employs 128~1024 times of over-sampling skill
Art.Voltage measurements are sent to single-chip microcomputer 5, and then calculate primary element 27 and reference member by the radiometer of two wire-end voltages
The resistance ratio of part 23, corrosion allowance is converted to using Ohm's law.
The sine waveform table of 16~64k bytes is had in single-chip microcomputer 5, by the D/A converter in waveform generator 1 according to
Waveform table exports the AC signal of different frequency, and is loaded into by potentiostatic circuit 4 WE 25 and RE of AC impedance probe
Between 24.Alternating voltage (U between WE and REAC) and auxiliary electrode (CE) 26 export ac current signal (IAC) by many
Passage A/D converter 7 is digitized, and finally by means of correlation intergal algorithm, calculates UACWith IACBetween Amplitude Ration and phase
Potential difference, is derived from the impedance spectrum of WE 25 under different frequency.Impedance measurements are saved in flash storage storage 3, may be used also
Geoceiver is sent to by communication interface 6.
The overall structure of downhole well corrosion monitoring device such as accompanying drawing 3.Wherein corrosion monitoring sensor 11 is fixed on stainless steel circle
In cylinder shell 31, the preferred external diameter of the cylinder is 25~35mm, and internal diameter is 20~30mm.The lead-out wire of probe 11 is connected to PCB
All electronic devices in including but not limited to accompanying drawing 1 are welded with plate 32, the pcb board.At the top of stainless steel cylinder 31,
A 1/4 " stainless steel sealing nut 30 has been connected through a screw thread it, the sealing nut central aperture, available for passing through armored cable.
Between the inwall of circular cylindrical shell 31 and the outer wall of combined probe 11 sealing is realized using 2~4 grades of PTFE seal circles.In cylinder 31
Bottom, is connected with a taper sheath 34, and the taper jacket surface is provided with many apertures 33, it is ensured that corrosive medium flows freely over spy
First 11, downhole corrosion medium is fully contacted the resistance probe in combined probe 11 and AC impedance probe, it is ensured that corrosion
Monitoring combined probe can truly reflect downhole corrosion state.Seal 30 and the corruption of bottom of the stainless steel cylinder 31 by top
Sealing ring 21 on the outside of erosion monitoring probe 11 and probe, forms a highly closed space, is that pcb board 32 provides good
Protection, it is ensured that corrosion monitor reliably working in the high temperature and high pressure environment of underground.
The main power source of downhole well corrosion monitoring device is provided by power regulator 9, and DC-DC built in power regulator 9 changes core
Piece and linear voltage stabilization chip, the 24~48V voltage step-downs that can provide well head power supply 10 are to 4~6V DC voltages, then pass through line
Property voltage stabilizing chip by its voltage stabilizing be 3.3V, be all analog/digital chip power supplies on pcb board 32.Downhole well corrosion monitoring device
Circuit in using real-time clock 2 realize self-timing wake up measurement, the Voltagre regulator that use can be turned off, in non-measured period
Power supply circuit is closed, to reduce power consumption.
Mounting means of the downhole well corrosion monitoring device in oil well is referring to Fig. 4.Data collector 40 is installed in well head, should
Transceiver is powered by well head power supply 10, has wireless transmitter module in transceiver 40, and measurement data can be sent to the corrosion of distal end
Surveillance center.Well head transceiver 40 is connected and realized with downhole well corrosion monitoring device 42 of the present invention by armored cable 41
Data communication, while also being powered by armored cable 41 to downhole well corrosion monitoring device 42.Armored cable 41 is then under oil pipe 43
The outside of oil pipe 43 is fixed on by clip 45 during well operations.Described downhole well corrosion monitoring device 42 be installed on oil well casing 44 with
In annular space between oil pipe 43, it can also be fixed in the tail pipe of oil pipe.Downhole well corrosion monitoring device 42 is fixed on annular
The a certain key position in space, measured resistance probe and AC impedance corrosion data are then transmitted in real time by armored cable 41
Corrosion Surveillance center is sent to well head transceiver 40, and by wirelessly or non-wirelessly network, facilitates administrative staff to look into whenever and wherever possible
See live corrosion condition.
Downhole well corrosion monitoring device 42 is removed to shaft bottom with during 43 operation of oil pipe one, and is fixed on apart from ground most deep 4000
In the oil well of rice.The device is communicated by the stainless steel cable 41 of the cores of RS485 tetra- with well head data collector 40, and by the latter
Power supply.Stainless steel cable 41 is fixed on the outer wall of oil pipe 43 by clip 45.The data collector 40 of well head is by wirelessly or non-wirelessly
Signal transmits data to central monitoring system, manager is checked downhole corrosion situation whenever and wherever possible.
This downhole well corrosion monitoring device is immersed in simulating oil field produced water, member is experienced in the compound corrosion monitoring sensor 11 of measurement
The corrosion allowance versus time curve of part 27, referring to Fig. 5.It can be seen that extension over time, in corrosive environment
Primary element corrosion allowance linear decline with the time.And Fig. 6 is then shown while the electricity that worked in the AC impedance probe of measurement
The curve that the instantaneous corrosion rate of pole 25 is stepped up with the time, shows the heap in working electrode surface with corrosion product
Product, makes the instantaneous corrosion rate of electrode progressively decline.The instantaneous corrosion rate and corrosion allowance measured respectively with reference to two methods,
It can will more fully characterize the general corrosion state with down-hole string same material sample in air-liquid complex environment.
As it will be easily appreciated by one skilled in the art that the foregoing is only presently preferred embodiments of the present invention, it is not used to
The limitation present invention, any modification, equivalent and the improvement made within the spirit and principles of the invention etc., it all should include
Within protection scope of the present invention.