CN105974385A - Horizontal well logging while drilling and ranging radar echo signal processing method - Google Patents

Abstract

The invention discloses a horizontal well logging while drilling and ranging radar echo signal processing method. The method includes the following steps that: 1, moving average filtering is performed on radar echo signals, wherein the radar echo signals include a direct wave signal component and a reflected wave signal component; step 2, Fourier transformation is performed on the signals obtained in the step 1, so that the signals can be transformed to the frequency domain from the time domain; step 3, band-pass filtering is performed on the signals; step 4, inverse Fourier transformation is performed on the signals obtained in the step 3, so that the signals can be transformed to the time domain from the frequency domain; step 5, the reflected wave signal component obtained in the step 4 is amplified; and 6, the peak time difference of the direct wave signal component and the reflection wave signal component in the signals obtained the step 5 is obtained, and the peak time difference can be applied to logging and ranging.

Description

Horizontal well is with probing layer range radar echo signal processing method

Technical field

The present invention, about oil, gas drilling field, returns with probing layer range radar especially with regard to for horizontal well Ripple signal processing method, is primarily adapted for use in drilling course, in real time with probing layer range radar, horizontal well is received reservoir The echo-signal on border processes, and obtains the key feature letter of the weak reflection ripple signal produced at reservoir separating surface in echo Breath, finally realizes the frontier probe of oil reservoir, coal seam and other reservoir, and this technology is the horizontal well core with probing layer range radar One of heart technology.

Background technology

Along with development and the continuous increase of oil-gas exploration and development difficulty of petroleum industry, petroleum exploration and development industry is It is increasingly turned to the oil-gas reservoir that exploitation scale is little, oil-gas Layer is thin, poor properties, anisotropism are strong, the special process such as directional well, horizontal well The application of well increases year by year.In the work progress of these special wells, need to grasp the rock stratum spy that drill bit is drilled in time Property, quick and precisely find reservoir, thus guiding construction personnel control drill bit runs in the guide in reservoir all the time, in order to greatest extent Improve recovery ratio.

For ensureing that drill bit creeps into all the time in reservoir, just need the up-and-down boundary face of measurement while drilling reservoir, it is ensured that drill bit is in Optimum position in reservoir.But, in actual creeping into, due to the limitation of existing detection instrument, often occur that drill bit drills Reservoir, or the optimum position in reservoir can not be maintained at, the recovery ratio of the resource such as Drilling ratio and oil gas of have impact on reservoir.

When propagating in underground medium due to frequency electromagnetic waves, there is violent relaxation phenomenon, and when reservoir and cap rock When difference between the dielectric constant of medium is little, the echo at separating surface will be the faintest.Simultaneously as stratum medium Not homogeneous property, cause the communication process of radar wave also to become sufficiently complex, the most serious to the interference of radar wave, cause play Strong decay and distortion, make useful reflection wave signal be submerged in noise, and be difficult to.If only by hardware circuit pair Faint radar return signal detects and identifies, then be far not by far up to the mark.

Summary of the invention

Horizontal well then can solve the problems referred to above well with probing layer range radar, and the present invention is horizontal exploratory shaft sinking layer range finding thunder One of core technology reached.

In order to extract faint radar return from noise and clutter, the present invention have devised corresponding numeral letter Number processing method.

The invention provides a kind of for horizontal well with probing layer range radar electromagnetic pulse reflected signal digital processing Method.When drilling tool pierces after reservoir starts horizontal drilling, and high-frequency electromagnetic pulse sequence launched by the transmitting antenna visiting layer range radar Row, owing to the relative dielectric constant of reservoir with cap rock there are differences, electromagnetic wave can occur anti-with the edge surface of cap rock at reservoir Penetrating, the reception antenna of range radar can receive this electromagnetic pulse reflected signal.The main object of the present invention is exactly to receiving sky The signal that line receives carries out Digital Signal Processing, the time difference that the most i.e. can get reflected signal with launch signal, in conjunction with Electromagnetic wave spread speed in each rock stratum, can calculate the up-and-down boundary face of reservoir even cap rock.

To achieve these goals, the present invention proposes a kind of horizontal well with probing layer range radar echo signal processing side Method: first, carries out moving average filter and bandpass filtering treatment to reading the Wave data obtained of sampling, filters out background noise Etc. random noise, improve signal to noise ratio；Secondly, auto gain control method, Gpr Signal communication process in the earth formation are used In, electromagnetic wave energy is decayed rapidly, and the amplitude being embodied in amplitude diminishes, and is unfavorable for the identification of radar data waveshape signal, permissible By automatic gain method, improve the amplitude of faint echo-signal, i.e. do not do at any amplification in the interval that signal is stronger Reason, only the interval to weak output signal carries out linear or index processing and amplifying, improves the gain amplifier to weak reflection signals, reaches To making the purpose of radar signal balancing energy, contribute to the tracking to weak reflection ripple signal and identification；Finally, complex value is used Morlet wavelet method, carries out detection and the identification of characteristic parameter to direct wave or reflection wave signal, obtain direct-path signal with The time difference of reflection wave signal, then substitute in patent of invention 201310128287.1, patent of invention 201310139143.6 and mention Velocity of EM-waves and visit layer distance-finding method, i.e. can get border, reservoir and the interplanar distance of drilling tool.

According to embodiments of the invention, it is provided that horizontal well with probing layer range radar echo signal processing method, including Following steps: step 1, radar echo signal carries out moving average filter, wherein, described radar echo signal includes direct wave Signal component and reflection wave signal composition；Step 2, the signal obtaining step 1 carry out Fourier transformation, it are changed from time domain For frequency domain；Step 3, described signal is carried out bandpass filtering；Step 4, the signal obtaining step 3 carry out inverse Fourier transform, It is converted to time domain from frequency domain；Reflection wave signal composition in step 5, the signal obtaining step 4 is amplified；Step 6, The signal obtained for step 5, the time to peak obtaining direct-path signal composition therein and reflection wave signal composition is poor, is used for Spy layer is found range.

The invention provides a kind of for horizontal well with probing layer range radar echo signal processing method.By this it is System, it is possible to achieve be filtered the weak reflection ripple signal in the echo-signal received, amplification etc. processes, obtain time domain and The relevant information of frequency domain, completes to transmit electromagnetic wave in reservoir the measurement work of time, in conjunction with electromagnetic wave in reservoir Velocity of wave information, i.e. can get the up-and-down boundary face of reservoir, thus realizes visiting layer, range finding effect, can control drill bit in real time and exist Reservoir creeps into, it is ensured that good reservoir Drilling ratio.

The beneficial effects of the present invention is:

1. significantly reduce the design difficulty of circuit, it is possible to achieve the complex process function that hardware circuit is difficult to. Such as, temporal scalable gain function, just there is bigger difficulty according to special hardware circuit, and compiled by common hardware+software Journey just can realize easily.Meanwhile, it is easy to change the parameter of whole system by programming, thus adapts to different reservoir and cap rock Environment, it is achieved various different process functions, has higher motility.

The most reliable and the most stable, processing accuracy is high, is not affected by factors such as circuit devcie internal noise and temperature drifts.

3. down-hole realizes the process to data.Use the present invention, it is not necessary to it is aboveground that the data gathered by receiving terminal transmit, Data just can be processed by down-hole in real time, solves a difficult problem for high-frequency signal real-time Transmission.

Accompanying drawing explanation

Fig. 1 for the embodiment of the present invention provide a kind of for horizontal well with probing layer range radar echo signal processing side Method flow chart；

Echo-signal after one group of sampling that Fig. 2 a-2d provides for the embodiment of the present invention is after signal processing method processes The exemplary plot of result.

Detailed description of the invention

Below, in conjunction with accompanying drawing, the enforcement of technical scheme is described in further detail.

Although it will be appreciated by those of skill in the art that the following description relates to a lot of of embodiment for the present invention Ins and outs, but be only for the example of the principle for the present invention is described and do not mean that any restriction.The present invention can be suitable for Occasion outside being different from ins and outs exemplified below, without departing from principle and the spirit of the present invention.

It addition, miscellaneous in order to avoid making the description of this specification be limited to, in description in this manual, may be to can be The portion of techniques details obtained in prior art data has carried out omission, simplification, accommodation etc. and has processed, and this is for the technology of this area Will be understood by for personnel, and this does not interferes with the open adequacy of this specification.

With detailed description of the invention, the present invention is described in further detail below in conjunction with the accompanying drawings.

Fig. 1 for the embodiment of the present invention provide for horizontal well with probing layer range radar echo signal processing method stream Cheng Tu.As it is shown in figure 1, described method includes:

The data gathered are carried out the random noises such as moving average filter, wiping out background noise by step S101；

Step S102, uses Fourier transformation (such as, DIT-FFT butterfly fast Fourier transform), further to data Process, discrete time domain data is transformed into frequency domain；

Step S103, uses band-pass filtering method, filters out other circuit of down-hole of below 200MHz and more than 500MHz The harmonic signal that the Electromagnetic Interference signal produced and signal source produce, it is ensured that receive is that reservoir produces with cap interface The direct-path signal that raw electromagnetic impulse reflection wave signal and transmitting antenna produce；

Step S104, uses inverse Fourier transform IFT method, the frequency-region signal processed is then converted to time-domain signal；

Step S105, uses time domain gain control method, i.e. controls signal time to be amplified in time domain interval, only Interval beyond direct-path signal is carried out linear or index processing and amplifying, only amplifies faint reflection wave signal, make reception Signal (direct wave and the echo) balancing energy arrived, is conducive to the detection to weak reflection ripple signal.It is right that time domain gain relies on Radar echo signal is multiplied by the gain weight function of time change and realizes, i.e.

$\tilde{y}\left(n\right)=\hat{y}\left(n\right)\·P\left(n\right),n=1,2,...,N---\left(1\right)$

In formula:For the digital waveform signal after moving average filter and bandpass filtering noise reduction, P (n) is automatically to increase Benefit weight function,For the digital waveform signal after automatic gain.

For the waveshape signal that energy is big, the weight factor taken advantage of should be little；For the waveshape signal that energy is little, the power taken advantage of The factor should be big.In order to make faint reflection wave signal that distortion, the weight function factor will not be occurred should to compare over time Slowly.

Asking for by the realization of signal added-time window, specifically, signal being divided into N number of of gain weight function P (n) Time window, and the overlap of window when window has half time each, make yield value that violent jump will not occur, then ask for window time each On mean amplitude of tide A_i, and by window mean amplitude of tide A time each_iWeighter factor P corresponding to window center point when calculating each_i。

Therefore, the mean amplitude of tide computing formula of i-th time window is

$A_i=\frac{\underset{n=T_{i-1}}{\overset{n=T_{i+1}}{\Σ}}\left|\hat{y}\left(n\right)\right|}{N}---\left(2\right)$

In formula: T_i-1For the initial time of i-th time window, T_i+1The termination time for i-th time window.

Gain weight function is

$P_i=\frac{1}{A_i}---\left(3\right)$

So can calculate to the gain weight P corresponding to i-th time window central point_i, window center when remaining is not Point gain weight, can by each adjacent time window linear interpolation obtain, so obtained each time delay point correspondence gain weight, from And each point is calculated gain P (n).

Step S106, uses complex value Morlet wavelet method, obtains envelope signal, carry out direct wave or reflection wave signal The detection of characteristic parameter and identification.

Morlet small echo is the cosine multiple modulation of Gaussian function, is given by:

$\mathrm{\ψ}\left(t\right)=(e^{{\mathrm{i\ω}}_{0}t}-e^{-\frac{{{\mathrm{\ω}}_0}^2}{2}})e^{-\frac{t^2}{2\mathrm{\σ}}},\mathrm{\σ}>0---\left(4\right)$

Corresponding Fourier is transformed to:

$\widehat{\mathrm{\ψ}}\left(\mathrm{\ω}\right)=\sqrt{2\mathrm{\π}\mathrm{\σ}}\[e^{-{(\mathrm{\ω}-{\mathrm{\ω}}_0)}^2/2\mathrm{\σ}}-e^{-\frac{{{\mathrm{\ω}}_0}^2}{2}}{e}^{-\frac{{\mathrm{\ω}}^2}{2\mathrm{\σ}}}\]---\left(5\right)$

Work as ω₀When=0, σ >=1,Namely

Work as ω₀When >=5,Then formula (5.14) can approximate and be rewritten as:

$\mathrm{\ψ}\left(t\right)=e^{{\mathrm{i\ω}}_{0}t}\·e^{-\frac{t^2}{2\mathrm{\σ}}},{\mathrm{\ω}}_0\≥5,\mathrm{\σ}\≥1---\left(6\right)$

Corresponding Fourier transformation is:

$\widehat{\mathrm{\ψ}}\left(\mathrm{\ω}\right)=\sqrt{2\mathrm{\π}\mathrm{\σ}}{e}^{-{(\mathrm{\ω}-{\mathrm{\ω}}_0)}^2/2\mathrm{\σ}},\mathrm{\σ}\≥1---\left(7\right)$

Because Morlet small echo is to be generated through cosine multiple modulation by Gaussian function, have good in time domain and frequency domain Localization property, the present embodiment Morlet small echo is carried out as the characteristic parameter of the mother wavelet function echo-signal to receiving Extract.

Step S107, by judging the method such as monotonicity or derivation, to the envelope signal after step S106 signal processing Process, draw the time parameter corresponding to envelope signal peak value, i.e. can get the time difference of direct wave and echo.

Step S108, substitutes in following velocity of EM-waves and spy layer distance-finding method according to this time difference, can realize visiting layer Distance measurement function, wherein, transmitting radar antenna and two reception antennas are mounted side by side on measurement drilling tool:

According to below equation, distance d of computation and measurement drilling tool to boundary face:

l₁=v₀t₁,

l₂=v₀t₂

L₁=v₁(t₁+Δt₁),

L₂=v₁(t₂+Δt₂),

$d=\sqrt{{L_1}^2-{l_1}^2}/2=\sqrt{{L_2}^2-{l_2}^2}/2,$

Wherein, l₁、l₂It is to launch antenna respectively to each distance in two reception antennas, L₁、L₂It is radar letter respectively From launching antenna to boundary face again to each propagation distance two reception antennas, t number in reservoir₁、t₂It is straight respectively Each time in arrived wave signal to two reception antenna, Δ t₁、Δt₂It is each reception in two reception antennas respectively Described time to peak in signal is poor, v₀It is electromagnetic wave spread speed in annular space, v₁It it is electromagnetic wave propagation in oil-gas Layer Speed.

The echo-signal after one group of sampling that Fig. 2 provides for embodiment of the present invention result after signal processing method processes Exemplary plot.Fig. 2 a show employing horizontal exploratory shaft sinking layer range radar system and is visiting in layer Range finding experiments, and receiving terminal sample circuit is adopted The initial data time domain beamformer that collection arrives；It is the initial data collected to be carried out moving average filter and carries logical shown in Fig. 2 b Oscillogram after filtering noise reduction, by comparing with Fig. 2 a, after moving average and bandpass filtering, significantly reduces and is The random noise of system inside and out, and unnecessary high and low frequency signal, the waveform after noise reduction is more smooth, and noise is subject to Certain compacting, signal to noise ratio is higher；Fig. 2 c show the waveform after automatic gain, by comparison diagram 2b, through automatically After gain method, direct wave can reduce with the contrast of reflection wave signal, and the most original reflection wave signal magnification level is through The degree that ripple amplifies is bigger, and reflection wave signal feature is the most obvious.Meanwhile, through after a period of time, after reflection wave signal After the weak electromagnetic ripple signal amplitude of a section is multiplied by bigger yield value, occur in that again the envelope letter of a similar reflection wave signal Number；The oscillogram that Fig. 2 d obtains after showing complex value Morlet wavelet transformation, by observing Fig. 2 d, the envelope of echo-signal Feature has been efficiently extracted out, meanwhile, except the direct wave of initial acquisition to data by complex value Morlet wavelet transformation With the feature of echo substantially outside, the doubtful reflection wave signal that obtains after automatic gain method processes is (i.e. in figure the 2 of mark Number echo) also clearly extracted.In a word, from Fig. 2 .d, we can clearly extract direct wave and echo Time value corresponding to signal peak, i.e. can get the time difference of direct wave and reflection wave signal, and this time difference is substituted into range finding Method, can realize visiting layer distance measurement function.

Finally, it will be appreciated by those of skill in the art that the above embodiment of the present invention can be made various amendment, change Type and replacement, it each falls within such as protection scope of the present invention defined in the appended claims.

Claims (6)

1. horizontal well is with a probing layer range radar echo signal processing method, comprises the following steps:

Step 1, radar echo signal carrying out moving average filter, wherein, described radar echo signal includes direct-path signal Composition and reflection wave signal composition；

Step 2, the signal obtaining step 1 carry out Fourier transformation, and from time domain, it is converted to frequency domain；

Step 3, described signal is carried out bandpass filtering；

Step 4, the signal obtaining step 3 carry out inverse Fourier transform, and from frequency domain, it is converted to time domain；

Reflection wave signal composition in step 5, the signal obtaining step 4 is amplified；

Step 6, the signal obtained for step 5, obtain direct-path signal composition therein and the peak value of reflection wave signal composition Time difference, is used for visiting layer range finding.

Horizontal well the most according to claim 1 is with probing layer range radar echo signal processing method, wherein, in step 3 In, filter Electromagnetic Interference signal and the radar signal of down-hole other circuit generation of below 200MHz and more than 500MHz The harmonic signal that source produces.

Horizontal well the most according to claim 1 is with probing layer range radar echo signal processing method, wherein, in step 2 In, described Fourier transformation is DIT-FFT butterfly fast Fourier transform.

Horizontal well the most according to claim 1 is with probing layer range radar echo signal processing method, wherein, in step 5 In, according to below equation, the signal obtaining step 4 processes:

$\tilde{y}\left(n\right)=\hat{y}\left(n\right)\·P\left(n\right),n=1,2,...,N---\left(1\right)$

In formula:The signal obtained for step 4, P (n) is automatic gain weight function,For the signal after processing, N is letter Number being averaged the sum of the time window being divided into, wherein, each time window has the overlap of half time window；

Wherein,

Wherein, A (n) is signal average in each time window.

Horizontal well the most according to claim 1 is with probing layer range radar echo signal processing method, wherein, in step 6 In, use complex value Morlet wavelet method, obtain the envelope of the signal obtained in step 5, and obtain direct-path signal therein The time to peak of the envelope of composition and reflection wave signal composition is poor, is used for visiting layer range finding.

Horizontal well the most according to claim 5 is with probing layer range radar echo signal processing method, wherein, radar emission Antenna and two reception antennas are mounted side by side on measurement drilling tool, and described method also includes:

Step 7, according to below equation, distance d of computation and measurement drilling tool to boundary face:

l₁=v₀t₁,

l₂=v₀t₂

L₁=v₁(t₁+Δt₁),

L₂=v₁(t₂+Δt₂),

$d=\sqrt{{L_1}^2-{l_2}^2}/2=\sqrt{{L_2}^2-{l_2}^2}/2,$

Wherein, l₁、l₂It is to launch antenna respectively to each distance in two reception antennas, L₁、L₂It is that radar signal exists respectively From launching antenna to boundary face again to each propagation distance two reception antennas, t in reservoir₁、t₂It is direct wave respectively Each time in signal to two reception antenna, Δ t₁、Δt₂It is each reception signal in two reception antennas respectively In described time to peak poor, v₀It is electromagnetic wave spread speed in annular space, v₁It is electromagnetic wave propagation speed in oil-gas Layer Degree.