CN1136668A - Hydrocarbon detecting method for seismic prospection - Google Patents

Abstract

The hydrocarbon detecting method for seismic prospection is a method directly seeking out oil and gas by using field seismogram. Said invention uses the different bandpass filters to make filtering for various traces passed through basic treatment, and on the same sampling point, for weighting coefficients of the different filtered values said invented method makes some calculation and comparison, and all the traces are passed through such treatment in the selected time window, so that the underground oil/gas accumulation band position can be seeked out and displayed, and formed into a hydrocarbon detecting diagram. Said diagram can display the whole morphology of oil/gas accumulation zone on the related stacked profile.

Description

Detecting method for seismic prospecting hydrocarbons

Detecting method for seismic prospecting hydrocarbons is a kind of digital seismogram that utilizes, and comes the method for direct oil prospecting gas finding by suitable digital processing.

About this method, Geophysics Prospecting Co., Daqing Petroleum Administrative Bureau has obtained the binomial patent, and the patent No. is respectively 87107616 and 89105573.8.This binomial patent substance and formula are: with digital tape recording, on the earthquake processor, do base conditioning, road, the superposition road that the seismologic record road is become did static and dynamic correction, select inclined to one side road.On with the bar survey line, to above-mentioned three kinds of roads choose any one kind of them or sorting after near the shot point road, by the patent No. 87107616 formula manipulation.

At i sampled point, establish Wherein, k=0,1,2 ..., n.N is the positive integer less than the sampled point number in road.

By the patent No. 89105573.8 formula manipulation:, establish at i sampled point Wherein, k=0,1,2 ..., n.N is the positive integer less than the sampled point number in road.

Sought the time window in, each sampled point is all calculated λ ' (t).All λ ' value (t) 〉=1 is divided into grade, and each level forms the symbol road with a machine symbol representative, and it is exactly hydrocarbon detection map that the symbol road is exported out.

By the patent No. another formula manipulation of 89105573.8: do i sampling With

Symbol relatively, might as well establish: Wherein, K=0,1,2 ..., n.N is the positive integer less than the sampled point number in road.

Get λ " (t _i) symbol.If λ " (t _i)＜0 is with arbitrary symbolic representation on the earthquake machine; λ " (t _i) 〉=0 usefulness blank is represented.Each sampled point is all done like this, formed the symbol road, the symbol road is exported out, also form hydrocarbon detection map.

The present invention is the theoretical foundation of 87107616,89105573.8 " detecting method for seismic prospecting hydrocarbons " according to the patent No. still, proposes the application of another " detecting method for seismic prospecting hydrocarbons ".

According to the theoretical foundation of method, can draw as the synoptic diagram of accompanying drawing 1,2,3,4.If underground have a horizontal individual layer of an of reservoir hydrocarbon, its reflection model is shown in 1.(ray [1], [2], [3] all are perpendicular slices and coincide together, for convenience of explanation, and they separately drawn.)

Incident wave direction [1], wave function b (t); Layer top reflection direction [2], wave function b ₁(t); Layer end reflection wave direction [3], wave function b ₂(t).B (t), b ₁(t), b ₂(t) frequency spectrum is B (f); B ₁(f); B ₂(f).

Fig. 2 is horizontal individual layer top, the reflection configuration at the end.[5] be b ₂(t) shape, [7] are b ₁(t) shape, [6] are sampled point t _iThe position.

If this layer reflection record road mainly is b ₁(t), b ₂(t) Zu He compound vibration.Reflection record is their algebraic sum.Then: d (t)=b ₁(t)+b ₂(t).

Suppose, when doing the earthquake processing, at bandpass filtering B (f ₁, f ₂, f ₃, f ₄) in, select f ₁=5, f ₃=7, f ₃=12, f ₄=15 o'clock, d (t) became d ' after the such low frequency bandpass filter filtering of seismic trace quilt _Low(t), b ₁(t) become b ' after filtered ₁(t), b ₂(t) become b ' after filtered ₂(t).Among Fig. 3 [8], [10] are respectively b ' ₂(t), b ' ₁(t) waveform.[9] be sampled point t _iThe position.At bandpass filtering B (f ₁, f ₂, f ₃, f ₄) in, f ₁=12, f ₂=15, f ₃=55, f ₄=60, d (t) became d ' after seismic trace was avoided near the wide band filter filtering of the low frequency the 10HZ like this _High(t).At bandpass filtering B (f ₁, f ₂, f ₃, f ₄) in, choosing is as f ₁=5, f ₂=7, f ₃=55, f ₄=60, d (t) becomes d ' after the such wide-band filter filtering of seismic trace quilt _Entirely(t).

The theoretical analysis of new method.Can find out from synoptic diagram 3 and Fig. 4: at t _iNear, d ' _Low(t) with d ' _High(t) Zhi opposite in sign.At t _iNear, establish

λ _-(t)=| d ' _Low(t)-d ' _High(t) |=| d ' _Low(t) |+| d ' _High(t) | λ is then arranged _-(t)＞| d ' _Low(t) |, λ _-(t)＞| d ' _High(t) |, λ _-(t)＞| d ' _Entirely(t) |.

At t _iNear, establish λ ₊(t)=| d ' _Low(t)+d ' _High(t) | λ+(t) is then arranged less than | d ' _Low(t) |, | d ' _High(t) | at least one value.If,

λ ₊(t)＞| d ' _High(t) | λ again ₊(t)＞| d ' _Low(t) |, then at t _iNear layer is hydrocarbon zone certainly not.

Equally, at t _iNear, establish

λ _-(t)=| a ₁D ' _Low(t)-a ₂D ' _High(t) |

λ ₊(t)=| a ₃D ' _Low(t)+a ₄D ' is (t) | a ₁, a ₂, a ₃, a ₄It is real number.Get a earlier _i(1≤i≤4) are certain real number, then to other three coefficients according to a _iAdjust definitely, make λ _-(t) and λ _-(t), λ ₊(t) and λ ₊(t) has same property.At t _iNear, use λ _-(t) and λ ₊(t) compare, can find out hydrocarbon zone as abnormal belt.

The way that adds coefficient in formula can make method have more ubiquity, fully reflects the thought of method.In addition, not so good to the demonstration of minority hydrocarbon zone, adjustable integral coefficient a ₁, a ₂, a ₃, a ₄, make the more obvious of hydrocarbon zone demonstration, be convenient to use.

D ' _High(t _I-j) be the value that near filtered i-j the sampled point of wide-band filter of the low frequency 10HZ avoided in all roads of choosing.

D ' _Entirely(t _I-j) be all roads of choosing, the value of i-j sampled point behind the full range filter filtering of the whole effective frequencies of involved seismologic record.

D ' _Low(t _I-j) be the choosing all roads by the value of filtered i-j the sampled point of low frequency bandpass filter.

D ' (t _I-j) be all roads of choosing, by the value of i-j sampled point after the another kind of band-pass filter.This bandpass filter is divided two kinds of situations, makes d ' (t _I-j) also in two kinds of situation: work as λ ₊(t) a in the formula ₃=0 o'clock, d ' (t _I-j) be to use the value of the bandpass filter of whole effective frequencies of being sought to filtered i-j the sampled point of seek, equal d ' _Entirely(t _I-j); Work as a ₃≠ 0 o'clock, d ' (t _I-j) be not influence the low-frequency band of being sought and comprise the value of the bandpass filter of all the other whole significant wave frequencies of seeking to filtered i-j the sampled point of seek with not comprising hydrocarbon zone, equal d ' _High(t _I-j).

The top several wave filter B (f that speak of ₁, f ₂, f ₃, f ₄) in the selection of frequency parameter, only need can include main frequency band as requested, just can calculate hydrocarbon detection map preferably.Therefore, the range of choice of concrete frequency parameter is bigger.It is main relevant with the field acquisition receive frequency with the lithology of oil bearing reservoir.With reference to fixed well, on processor, do experiment and can choose the frequency band parameter preferably.

According to above analysis, this method can be described like this.The content of this method is:

With the field tape record, in the earthquake processor, do base conditioning, make the seismologic record road become the road of doing static and dynamic correction, the superposition road, inclined to one side road changes.On the same line, to above-mentioned three kinds of roads choose any one kind of them or sorting after near the shot point road, do following processing, handle formula and be:

At i sampled point, establish

λ ' _-(t _I-j)=a ₁D ' _Low(t _I-j)-a ₂D ' _High(t _I-j)

λ ' ₊(t _I-j)=a ₃D ' _Low(t _I-j)+a ₄D ' (t _I-j) ${\stackrel{-}{\mathrm{\λ}}}_1\left(t_i\right)=\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}\left|{\stackrel{-}{\mathrm{\λ}}}_{-}^{\′}\left(t_{i-j}\right)\right|{---\stackrel{-}{\mathrm{\λ}}}_2\left(t_i\right)=\left|\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}{\stackrel{-}{\mathrm{\λ}}}_{-}^{\′}\left(t_{i-j}\right)\right|$ ${\stackrel{-}{\mathrm{\λ}}}_3\left(t_i\right)=\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}\left|{\stackrel{-}{\mathrm{\λ}}}_{+}^{\′}\left(t_{i-j}\right)\right|{---\stackrel{-}{\mathrm{\λ}}}_4\left(t_i\right)=\left|\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}{\stackrel{-}{\mathrm{\λ}}}_{+}^{\′}\left(t_{i-j}\right)\right|$ ${\mathrm{\λ}}_1\left(t_i\right)=\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}\left|{\stackrel{-}{\mathrm{\λ}}}_{-}^{\′}\left(t_{i-j}\right)\right|/\left|{\stackrel{-}{\mathrm{\λ}}}_{+}^{\′}\left(t_{i-j}\right)\right|$

λ ₂(t _i)＝ λ ₁(t _i)/ λ ₃(t _i) λ ₃(t _i)＝ λ ₁(t _i)/ λ ₄(t _i)

λ ₄(t _i)=λ ₂(t _i)/λ ₃(t _i) λ ₃(t _i)=λ ₂(t _i)/λ ₄(t _i) wherein, K=0,1,2 ..., n.N is the positive integer less than the sampled point number in road.

(1) if λ _j(t _i) 〉=b sets up (b is a constant for 1≤j≤5, b＞0), then at t _iSampled point keep former amplitude (with other nonzero values also can).Otherwise, t _iThe value of sampled point replaces with zero.Equally, on the contrary also can substitute t _iThe value of sampled point.The selection of b is according to coefficient a ₁, a ₂, a ₃, a ₄Show matching degree with the hydro carbons of fixed well and decide.

When selected, in the window, the per pass sampled point is all done like this.Then, add the area way with waveform or waveform and show, form hydrocarbon detection map.Also can when selected, in the window, all calculate λ to per pass to each sampled point _i(t) (1≤i≤5).At a certain sampled point λ _i(t)＜and b, this sampled point replaces with null value; To λ _i(t) 〉=λ of b _i(t) value is divided into grade, and each grade substitutes the value of sampled point with a machine symbol.Per pass is all done like this in the window when selected, forms the symbol road, and the symbol road is exported out, also forms hydrocarbon detection map.

(2) to described in (1), effect is best when n=0, at this moment

λ _j(t _i)=| λ ' _-(t _i) |/| λ ' ₊(t _i) | (1≤j≤5) other processing and demonstration way are with identical described in (1).

(3) to formula λ _j(t _i) (1≤j≤5) desirable inverse, the formula of getting behind the inverse is easily found out condition and the demonstration way of judging hydrocarbon zone from (1) and (2), no longer discuss here.

Predicting oil band how.On hydrocarbon detection map, except hydrocarbon zone is shown, also reservoir bed is shown by net thickness.With the way of frequency sweeping, different because of oil gas with the frequency adaptability of water, the pool is separated.All very successful experiences of Daqing oil field the 9th oil recovery factory's geology in this respect.

How to see detection figure.Be that directions X CDP counts shown in the top of figure.Vertically be t ₀Time.According to fixed well, the known oil storage band of gas, reservoir formation shown in hydro carbons detects, the best that meets, the demonstration of figure is the strongest, and what the symbol demonstration was the most intensive is best.

Claims (3)

1. one kind is utilized seismologic record, comes the method for direct oil prospecting gas finding by suitable digital processing.With the field tape record, on the earthquake processor, do base conditioning, road, the superposition road that the seismologic record road is become did static and dynamic correction, select inclined to one side road.

It is characterized in that: on the bar survey line, to above-mentioned three kinds of roads choose any one kind of them or sorting after near the shot point road, do following processing, handle formula and be:

At i sampled point, establish

λ ' _-(t _I-j)=a ₁D ' _Low(t _I-j)-a ₂D ' _High(t _I-j)

λ ' ₊(t _I-j)=a ₃D ' _Low(t _I-j)+a ₄D ' (t _I-j) ${\stackrel{-}{\mathrm{\λ}}}_1\left(t_i\right)=\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}\left|{\stackrel{-}{\mathrm{\λ}}}_{-}^{\′}\left(t_{i-j}\right)\right|{---\stackrel{-}{\mathrm{\λ}}}_2\left(t_i\right)=\left|\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}{\stackrel{-}{\mathrm{\λ}}}_{-}^{\′}\left(t_{i-j}\right)\right|$ ${\stackrel{-}{\mathrm{\λ}}}_3\left(t_i\right)=\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}\left|{\stackrel{-}{\mathrm{\λ}}}_{+}^{\′}\left(t_{i-j}\right)\right|{---\stackrel{-}{\mathrm{\λ}}}_4\mathrm{\λ}\left(t_i\right)=\left|\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}{\stackrel{-}{\mathrm{\λ}}}_{+}^{\′}\left(t_{i-j}\right)\right|$ ${\mathrm{\λ}}_1\left(t_i\right)=\underset{j=0}{\overset{\±K}{\mathrm{\Σ}}}\left|{\stackrel{-}{\mathrm{\λ}}}_{-}^{\′}\left(t_{i-j}\right)\right|/\left|{\stackrel{-}{\mathrm{\λ}}}_{+}^{\′}\left(t_{i-j}\right)\right|$

λ ₂(t _i)＝ λ ₁(t _i)/ λ ₃(t _i) λ ₃(t _i)＝ λ ₁(t _i)/ λ ₄(t _i)

λ ₄(t _i)=λ ₂(t _i)/λ ₃(t _i) λ ₃(t _i)=λ ₂(t _i)/λ ₄(t _i) wherein, K=0,1,2 ..., n.n is the positive integer less than the sampled point number in road.a ₁, a ₂, a ₃, a ₄It is real number.Get a earlier _i(1≤i≤4) are certain real number, then to other three coefficients according to a _iAdjust definitely, make | λ ' _-(t _I-j) | with | d ' _Low(t _I-j)-d ' _High(t _I-j) |, | λ ' ₊(t _I-j) | with | d ' _Low(t _I-j)+d ' _High(t _I-j) | have same property.

D ' _High(t _I-j) be the value that near filtered i-j the sampled point of wide-band filter of the low frequency 10HZ avoided in all roads of choosing.

D ' _Entirely(t _I-j) be all roads of choosing, the value of i-j sampled point behind the full range filter filtering of the whole effective frequencies of involved seismologic record.

D ' _Low(t _I-j) be the choosing all roads by the value of filtered i-j the sampled point of low frequency bandpass filter.

D ' (t _I-j) be all roads of choosing, by the value of i-j sampled point after the another kind of band-pass filter.This bandpass filter is divided two kinds of situations, makes d ' (t _I-j) also in two kinds of situation: work as λ ₄(t) a in the formula ₃=0 o'clock, d ' (t _I-j) be to use the value of the bandpass filter of whole effective frequencies of being sought to filtered i-j the sampled point of seek, equal d ' _Entirely(t _I-j); Work as a ₃≠ 0 o'clock, d ' (t _I-j) be not influence the low-frequency band of being sought and comprise the value of the bandpass filter of all the other whole significant wave frequencies of seeking to filtered i-j the sampled point of seek with not comprising hydrocarbon zone, equal d ' _High(t _I-j).

The top several wave filter B (f that speak of ₁, f ₂, f ₃, f ₄) in the selection of frequency parameter, only need can include main frequency band as requested, just can calculate hydrocarbon detection map preferably.Therefore, the range of choice of concrete frequency parameter is bigger.It is main relevant with the field acquisition receive frequency with the lithology of oil bearing reservoir.With reference to fixed well, on processor, do experiment and can choose the frequency band parameter preferably.

If λ _j(t _i) 〉=b sets up (b is a constant for 1≤j≤5, b＞0), then at t _iSampled point keep former amplitude (with other nonzero values also can).Otherwise, t _iThe value of sampled point replaces with zero.Equally, on the contrary also can substitute t _iThe value of sampled point.The selection of b is according to coefficient a ₁, a ₂, a ₃, a ₄Show matching degree with the hydro carbons of fixed well and decide.

When selected, in the window, the per pass sampled point is all done like this.Then, add the area way with waveform or waveform and show, form hydrocarbon detection map.Also can when selected, in the window, all calculate λ to per pass to each sampled point _i(t) (1≤i≤5).At a certain sampled point λ _i(t)＜and b, this sampled point replaces with null value; To λ _i(t) 〉=λ of b _i(t) value is divided into grade, and each grade substitutes the value of sampled point with a machine symbol.Per pass is all done like this in the window when selected, forms the symbol road, and the symbol road is exported out, also forms hydrocarbon detection map.

2. according to the described detecting method for seismic prospecting hydrocarbons of claim 1, it is characterized in that: effect is best when n=0, at this moment

λ _j(t _i)=| λ ' _-(t _i) |/| λ ' ₊(t _i) | (1≤j≤5) other processing and demonstration way are with identical described in 1..

3. to formula λ _j(t _i) (1≤j≤5) desirable inverse, get condition and demonstration way that formula behind the inverse is judged hydrocarbon zone, easily from 1. and 2., find out.

Predicting oil band how.On hydrocarbon detection map, except hydrocarbon zone is shown, also reservoir bed is shown by net thickness.With the way of frequency sweeping, different because of oil gas with the frequency adaptability of water, the pool is separated.All very successful experiences of Daqing oil field the 9th oil recovery factory's geology in this respect.

How to see detection figure.Be that directions X CDP counts shown in the top of figure.Vertically be t ₀Time.According to fixed well, the known oil storage band of gas, reservoir formation shown in hydro carbons detects, the best that meets, the demonstration of figure is the strongest, and what the symbol demonstration was the most intensive is best.

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