CN1187584C - Casing stress detecting probe and instrument for oil and water well - Google Patents

Abstract

The present invention relates to a casing pipe stress detecting probe for an oil and water well, which is a probe combining an MBN probe or an MAE probe head or an MBN probe and the MAE probe. The probe is provided with an iron core provided with an exciting coil, and the probe can generate an alternating magnetic field so that the casing pipe is magnetized. The casing pipe generates a barkhausen effect and a magnetic-acoustic emission effect, the MBN probe receiving the barkhausen effect is an induction coil, and the MAE probe receiving the magnetic-acoustic emission effect is a piezoelectric crystal sensor. The probe is placed in the casing tube and is abutted to the inner wall of the casing pipe by an arm pushing and abutting mechanism. One or more probes are arranged in the casing pipe, and a plurality of probes are orthogonally distributed. The input end of the exciting coil of the probe and the output of a probe signal are connected with an interface of a detection control instrument. The present invention can detect a stress state of the casing pipe and can predict the part of the casing pipe where is to be damaged by analyzing a measured stress curve.

Description

Casing Failure stress detecting probe and detection instrument

Affiliated technical field

The present invention relates to a kind of oilfield engineering detection probe and detection instrument, the especially a kind of detection probe of Casing Failure stress damage and detection instrument of making based on this probe predicted.

Background technology

In oilfield development process, oil recovery and water filling change the stress on stratum, cause the stress abnormality of underground a certain position, the variation of stress is delivered on the sleeve pipe of oil-water well, cause the sleeve pipe of producing well and water injection well under the effect of ABNORMAL STRESS, to deform, break and bad break, influence the ordinary production in oil field, sleeve pipe damages needs a large amount of funds to repair, and has increased the field produces cost.The sleeve pipe of oil, well damages and can only judge position and the damaged condition that cover decreases by arm Caliper Log after sleeve pipe damages generation at present.

Summary of the invention

The object of the present invention is to provide a kind of Casing Failure stress detecting probe and detection instrument, it can be before cover decreases generation, stress to sleeve pipe detects, by the stress curve that records is analyzed, the prediction sleeve pipe damages the position that will take place, thus the generation that the prevention cover decreases.

The objective of the invention is to be achieved through the following technical solutions:

A kind of Casing Failure stress detecting probe which comprises at least an iron core that has drive coil that can produce alternating magnetic field, is provided with in the core field to detect inductive coil that Barkhausen's magnetic makes an uproar and constitute Barkhausen's magnetic probe of making an uproar; Comprise that also a piezoeletric quartz sensor that can detect the magnetosonic emission constitutes magnetosonic emission effect probe; Make an uproar probe and magnetosonic emission effect probe of Barkhausen's magnetic is wholely set on the pole plate of popping one's head in.

A kind of Casing Failure tension gauge device, by above-mentioned Casing Failure stress detecting probe with detect control instrument and forms, its probe promptly can be MBN probe or MAE probe or pops one's head in and the MAE probe incorporated for MBN.This probe is placed on and is arranged in the sleeve pipe on to be measured, and the output of the input of the drive coil of probe and probe induction connects the interface that detects control instrument.

Casing stress detecting probe is more than one, and employing positioning arm mechanism contacts the inwall at sleeve pipe, and probe can be omnidirectional distribution.

Detect control instrument and comprise probe coil exciting circuit, signals collecting analog amplify circuit, central control unit CPU, wherein the signals collecting analog amplify circuit connects the input end of CPU, CPU output control terminal wiring circle exciting circuit.The CPU output terminal is connected to display, input termination keyboard, and communication port connects remote system.The signals collecting analog amplify circuit is made of preposition amplification, multichannel filtering and analog to digital conversion circuit.The signal of the synthetic automatic gain feedback circuit of the output signal of CPU control end connects the probe drive coil again.

The automatic gain feedback circuit is made of the transducing signal feedback circuit and the adjusting control circuit of probe body.

The present invention can be by the detection to the suffered stress of sleeve pipe before sleeve pipe is damaged, find the concentrated position of subsurface anomaly stress, in the zone that will overlap damage, by timely adjustment water filling, oil recovery scheme, make unusual stress obtain discharging, thereby avoid overlapping the generation of damage, can save a large amount of well workovers and the fund of drilling well again.

Description of drawings

Fig. 1 is the magnetization curve and the magnetic hysteresis loop distribution schematic diagram of barkhausen.

Fig. 2 is a probe inner structure synoptic diagram of the present invention;

Fig. 3 is arranged on the interior structural representation of sleeve pipe for probe of the present invention;

Fig. 4 is that circuit of the present invention constitutes block diagram.

Embodiment

The present invention is described in further detail below in conjunction with the drawings and specific embodiments.

Ferromagnetic material has domain structure, and its direction of magnetization is an easy axis.According to minimum energy principle, the rock-steady structure of magnetic domain always tends to the state of energy minimum.When the effect of outside magnetic field was magnetized down, rotated on domain wall displacement or farmland, and the farmland of domain wall trend external magnetic field is enlarged, and reverse farmland dwindles.The domain wall displacement process need constantly overcome the potential energy barrier that factors such as non-homogeneous stress that material internal exists, impurity, air cause, thereby be discrete, the irreversible motion of great-jump-forward shows that magnetization curve and magnetic hysteresis loop steepest zone shown in Figure 1 changes for the staged jumping characteristic.As a conductor coils is placed material surface, add an alternating magnetic field, then the irreversible jump of neticdomain wall will be responded to a series of voltage pulse signals in coil, can hear the sound that rustles after the amplification, claim magnetic noise.This phenomenon is that roentgen Barkhausen finds, claims barkhausen, and the magnetic noise is called for short MBN.

Simultaneously, ferromagnetic material has magnetostrictive effect, and magnetostriction coefficient is anisotropic.When domain wall carries out Barkhausen when jumping, can produce bulk strain, the energy of accumulating will discharge with the form of elastic wave, if a piezoeletric quartz sensor is placed the sample surfaces of alternating magnetic field, can detect the signal that a series of sound pulse encourages, be called the magnetosonic emission, be called for short MAE.The MAE potential pulse amplitude that each Pasteur's jump is evoked can be expressed as: V=C Δ ε I Δ V/ τ, and C is a coefficient in the formula, Δ ε is the strain tensor that domain wall moves volume delta V, the time of τ for continuing.Theoretical analysis shows that the irreversible displacement of 180 ° of domain walls does not produce magnetic strain, thereby does not have MAE, and the irreversible jump of 90 ° of domain walls is the main sources that produce MAE.For MBN, the irreversible displacement of 180 ° of domain walls is main sources, and the irreversible displacement of 90 ° of domain walls and rotation produce more weak MBN signal.

The stress state of material directly influences the pinning on irreversible displacement of domain wall and the direction of easy axis, and stress and magnetic domain interact and produce additional magnetoelastic energy.Concerning the ferrous materials with positive magnetic hysteresis flex effect, tension is that 180 ° of farmlands increase, and the farmland of 90 ° of farmlands and other type dwindles, thereby tension causes the MBN signal to strengthen the MAE signal weakening on direction of magnetization.And the compressive stress effect is just in time opposite, and MBN increases with pressure and weakens, and MAE then strengthens.

Casing stress detecting probe of the present invention has utilized the relation of magnetosonic emission effect MAE and barkhausen MBN and stress just, by detecting the stress state that MAE and MBN signal obtain sleeve pipe.

Concrete structure shown in Fig. 2,3,4, the detecting instrument that the invention provides a kind of Casing Failure stress detecting probe and constitute according to this probe.Wherein probe can be MBN probe 11 or MAE probe 12, and perhaps MBN probe 11 and MAE 12 probes that combine 1 of popping one's head in can be independently or be installed in integratedly on the pole plate 2 of popping one's head in.Barkhausen MBN probe 11 produces magnetic field for having the iron core 13 of drive coil 14, and the variation of inductive coil 11 induction sleeve pipes 3 inboard wall stress produces the magnetic noise signal; Magnetosonic emission effect MAE probe 12 is a piezoeletric quartz sensor, can detect the magnetosonic emission.Probe 1 is placed in the sleeve pipe 3, the inwall that adopts positioning arm mechanism 4 to contact at sleeve pipe 3.Usually the probe 1 in the sleeve pipe 3 is one or more, and probe 1 can be omnidirectional distribution.The output of the input of the drive coil 14 of probe 1 and probe induction connects the interface that detects control instrument.

Like this, casing stress detects and adopts the backup metering system that is similar to four arm hole diameters, magnetoelastic sensor probe of the present invention all is housed on four positioning arms, as the orientation well logger is housed on instrument simultaneously, can obtain 2 CAL, 8 magnetoelasticity curves, 1 orientation curve simultaneously, by acquired signal is carried out the size and Orientation that corresponding Treatment Analysis can draw casing deformation form and major principal stress.

Therefore, the present invention is incorporated into one with barkhausen and magnetosonic emission effect, has fully used both following characteristics: the increase MBN with tension strengthens, and MAE then weakens, and therefore, MBN changes responsive to tension, and MAE is then to the compressive stress sensitivity; The detection signal of MBN is restricted by skin effect, and it detects the degree of depth by the decision of signal frequency range to given material, and the MAE signal is not subjected to the influence of skin effect, and it is bigger that it detects the degree of depth; The original signal of MAE is as elastic wave, and its propagation characteristic is relevant with the shape and size of material, and MBN is then irrelevant therewith.

Instrument of the present invention is used for the detection signal according to above-mentioned probe, calculates automatically, stores the measurement result of popping one's head in, and by curve or data the result is showed, and perhaps also can give tele-control system with data transfer by communication port.

Referring to Fig. 4, the constituting of instrument of the present invention: probe exciting circuit, analog amplify circuit, automatic gain feedback circuit, control system.

Exciting circuit: constitute by waveform generator and power amplifier, its function provides the electric current of the drive coil of sensor with certain frequency and intensity, so that when test material, produce suitable variation magnetic field, the magnetic field power has direct influence to signal, magnetic field can not be strong excessively, otherwise signal is tending towards saturated; Magnetic field levels is low excessively, then signal too a little less than, cause detection sensitivity to worsen.Therefore according to the magnetic characteristic of experiment material, selecting corresponding variation magnetic field, is to guarantee that instrument obtains the essential condition of optimum sensitivity.

Mimic channel: MBM and MAE are more weak by the signal that sensor receives, and are generally 10 μ V magnitudes, and signal needs to send CPU to handle again through prime amplifier, main amplifier and filtering.The MBN filtering system adopts the multichannel filtering mode of different frequency section, in the hope of obtaining several alternative detection thickness.Because according to the skin effect theory, effectively detect the degree of depth (d) and be by frequency (f) decision of conductivity of electrolyte materials (ρ), magnetic permeability (μ) and signal, its $d=\sqrt{\mathrm{\ρ}/\mathrm{\π\μf}},$ According to conductivity, the magnetic permeability of test material, the different frequency of design, then the relevant detection degree of depth can be from the superficial to the deep.

Because MAE is an elastic wave, its detection degree of depth and signal frequency relation are little, and be only relevant with the excitation low frequency, so it is big to detect the degree of depth, adopts the narrow-band filtering mode in circuit design.Two analog circuitry systems adopt multiple measure to suppress noise and raising antijamming capability, are intended to guarantee that system has good signal-to-noise.

Automatic gain feedback circuit: in order to eliminate of the influence of test material physical dimension, adopted closed loop voltage negative feedback control circuit, realized automatic adjusting to signal amplitude to magnetic field.Tickler obtains and magnetizes the magnetic induction voltage signal that magnetic leakage flux is directly proportional, through amplification, finishing, filtering etc., synthetic at the setting magnetic field voltage signal that control circuit and CPU send here, deliver to the excitatory waveform signal multiplication of exporting with waveform generator in the multiplier circuit again, after power amplifier flows to drive coil, thereby realize the automatic control of excitation field field intensity.

Control system: have two CPU to constitute, its function is that signal is sampled automatically, handles, shown and magnetizing field is regulated.The information of signal obtains by a plurality of peak values being got weighted-average method.Instrument can be stored the code test curve of multiple shell material, can show the absolute value that detects stress automatically by this.

The logging instrumentation that the present invention adopts the magnetoelasticity probe to make can detect oil, well casing stress state, and the prediction cover decreases happening part.Log well 500 mouthfuls per year, individual well is charged 2.5 ten thousand yuan, can obtain 1,250 ten thousand yuan economic benefit, and by reducing 500 mouthfuls of casing damaged wells, individual well is saved 100,000 yuan of workover costs, can be the oil field and saves 3,750 ten thousand yuan.

Claims (8)

1, a kind of Casing Failure stress detecting probe is characterized in that: which comprises at least an iron core that has drive coil that can produce alternating magnetic field, be provided with in the core field and detect Barkhausen's magnetic that inductive coil that Barkhausen's magnetic makes an uproar constitutes probe of making an uproar; Also comprise the magnetosonic emission effect probe that a piezoeletric quartz sensor that can detect the magnetosonic emission constitutes; Make an uproar probe and magnetosonic emission effect probe of Barkhausen's magnetic is wholely set on the pole plate of popping one's head in.

2, a kind of Casing Failure tension gauge device, which comprises at least probe as claimed in claim 1 and detect control instrument, it is characterized in that: described probe is inserted in the Casing Failure, and the input of probe drive coil and the output of probe signal connect the interface that detects control instrument.

3, Casing Failure tension gauge device according to claim 2 is characterized in that: the probe in the sleeve pipe is one or more, and employing positioning arm mechanism contacts the inwall at sleeve pipe, and a plurality of probe orthogonals distribute.

4, Casing Failure tension gauge device according to claim 3, it is characterized in that: detect control instrument and comprise probe coil exciting circuit, signals collecting analog amplify circuit, central control unit CPU, wherein the signals collecting analog amplify circuit connects the input end of CPU, CPU output control terminal wiring circle exciting circuit.

5, Casing Failure tension gauge device according to claim 4, it is characterized in that: the CPU output terminal is connected to display, input termination keyboard, communication port connects remote system.

6, Casing Failure tension gauge device according to claim 4, it is characterized in that: the signals collecting analog amplify circuit is made of preposition amplification, multichannel filtering and analog to digital conversion circuit.

7, Casing Failure tension gauge device according to claim 4 is characterized in that: the signal of the synthetic automatic gain feedback circuit of the output signal of CPU control end connects the probe drive coil again.

8, Casing Failure tension gauge device according to claim 4 is characterized in that: the automatic gain feedback circuit is made of the transducing signal feedback circuit and the adjusting control circuit of probe body.

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