CN101598804B - Three-dimensional method for determining structure of underground oil-gas reservoir - Google Patents

Abstract

The invention relates to a three-dimensional method for determining the structure of an underground oil-gas reservoir. The method comprises the following concrete steps: obtaining a velocity field and a density field of transverse waves and longitudinal waves conforming to underground geologic structure by processing; carrying out linear encryption interpolation on a dispersion field renewedly according to observation system parameters and the dispersion field so as to adapt the requirement for rebuilding a wave field; rebuilding wave field values on each net point at each moment on the basis of the dispersion field; outputting a pure P wave field and a pure S wave field at a position where a demodulator probe is located at each moment to be used as a wave field rebuilding record of the moment; and comparing stacking and excursion sections obtained from wave field rebuilding and stacking and excursion sections obtained by processing field collected data to determine the configuration and the position of the structure of the underground oil-gas reservoir. In the invention, the recoded longitudinal wave and the recorded transverse wave obtained from wave field rebuilding are completely separated so that the separation of the longitudinal wave field and the transverse wave field is not needed in the subsequent wave field research.

Description

Confirm the three-dimensional method of subterranean oil gas reservoir structure

Technical field

The present invention relates to petroleum prospecting and development technique; Specifically be a kind of under staggered-mesh, realize have the wave-field reconstruction precision high, rebuild the efficient height and frequency dispersion low, and definite underground oil and gas of separating of the p ripple s wavelength-division of can large-scale promotion using is hidden the three-dimensional method of structure.

Background technology

In the reflection wave seismic prospecting; Through what adopt focus (explosive source, vibroseis or weight focus) to excite to obtain on ground is the reflective information (like seismologic record) that comes from underground geologic bodies; Need handle imaging section (comprising stacked section and migrated section) and the velocity field (comprising stacking velocity field and interval velocity field) that (comprising static correction, NMO correction, stack and skew or the like) obtains to be used for geologic interpretation through a series of seismic data for the reflective information that has obtained; Imitate the reflective information (process of this reconstruction underground geologic bodies reflective information also is referred to as the wave-field reconstruction process) that open-air earthquake data acquisition process is rebuild geologic body according to the interval velocity field that obtained, then with wave-field reconstruction to the reflective information of reflective information and open-air actual acquisition compare and analyze definite underground hydrocarbon reservoir structure.

Process that it should be noted that underground geologic bodies reflective information wave-field reconstruction and definite subterranean oil gas reservoir structure plays a very important role for geologic interpretation, hydrocarbon reservoir structure description and hydrocarbon-bearing pool exploitation.The process ability true reappearance seismic event of wave-field reconstruction has very important meaning in the overall process of underground propagation to architectonic understanding.The input of wave-field reconstruction is the interval velocity field that early stage, the seismic data data processing obtained, and this interval velocity field meets this area's geologic feature.Obtain being similar to the seismologic record of open-air earthquake data acquisition through wave-field reconstruction.Usual condition is marched off into political wilderness, and to adopt simple component to accept seismologic record be that vertical component is accepted (be also referred to as Z component and accept promptly to accept the vibrations with the surface level vertical direction) for outer earthquake data acquisition.Present many component is accepted also more and more, also accepts two components (component of directions X and Y direction) of horizontal direction except the component of accepting to come from vertical direction, and horizontal direction has an X and two components of Y under three-dimensional situation.In each component, not only comprise compressional wave (also claiming the P ripple) information but also comprise shear wave (also claiming the S ripple) information (being referred to as to mix wave field).In indoor wave-field reconstruction process, also can draw the record of each component.

Ripple can transform each other in length and breadth in the propagation of seismic wave process, and promptly compressional wave can convert shear wave into, and same shear wave also can convert compressional wave into, and ripple is coupled in length and breadth.

At present; Three-dimensional perfect elasticity wave equation numerical value wave-field reconstruction in homogeneous isotropic medium can only obtain the mixing wave field (not only comprising the P ripple but also comprise the S ripple in X component, Y component and the Z component) of each component; What at first will do when handling is exactly wave field separation in follow-up many ripples data (promptly comprise compressional wave in the record and comprise shear wave and converted shear wave again with the conversion compressional wave); Isolate pure P ripple and pure S ripple, but general being difficult to separated it fully.If rebuild the P ripple separately with the compressional wave equation; The shear wave equation is rebuild the S ripple separately; P ripple and conversion S ripple then can not appear in the wave field changing; Thereby with the non-equivalence as a result of complete wave-field reconstruction, also can not get any reconstructed results of transformed wave, this is for the result who confirms subterranean oil gas reservoir structure effect of can misleading.

Therefore; To guarantee at present under the prerequisite that the all-wave field information is rebuild; Realize the wave-field reconstruction of decomposition fully of pure compressional wave and pure shear wave; Be that the P ripple that is comprised in X component among the wave-field reconstruction result, Y component and the Z component separates with the S ripple fully, so in follow-up many ripples Data Processing, need not carry out wave field separation.This all has important practical sense for research propagation of seismic wave mechanism and to structure and the reservoir description of studying underground geologic bodies.

Ma Detang has proposed to use the second-order partial differential coefficient equations for elastic waves and has realized the elasticity wave-field reconstruction that wavelength-division is in length and breadth left in 2003, efficient is low, the numerical value frequency dispersion seriously is not suitable for large-scale promotion and uses but this method is rebuild.The single order partial derivative equations for elastic waves numerical value wave-field reconstruction of at present epidemic rate-stress; In this method process of reconstruction, find the solution through employing staggered-mesh method (in the process of wave field numerical reconstruction, adopting half grid computing); Its major advantage is to carry out the space differentiate to the elastic constant of medium (known speed and density field), thereby the efficient of numerical value wave-field reconstruction and precision are all good than second-order partial differential coefficient equations for elastic waves.

Patented claim CN101173988 discloses the elasticity wave field method for reconstructing of having realized under the two-dimentional single order staggered-mesh that wavelength-division is in length and breadth left, but can not realize under the three-dimensional single order staggered-mesh situation complete wave field being decomposed reconstruction.

Summary of the invention

The purpose of this invention is to provide a kind of have the wave-field reconstruction precision high, rebuild the efficient height and frequency dispersion low, and definite underground oil and gas of separating of the p ripple s wavelength-division of can large-scale promotion using is hidden the three-dimensional method of structure.

Practical implementation step of the present invention comprises:

1) open-air actual observation system acquisition data are confirmed the reconstruction parameter in the wave-field reconstruction process;

The reconstruction parameter of the described reconstruction parameter of step 1) comprises shot interval, distance between centers of tracks, track pitch, big gun number, road number, SI, road length, cautious X, Y coordinate and the corresponding elevation of big gun.

2) adopt usual way that geological data is carried out handling early stage interval velocity field of ripple in length and breadth and the density field that obtains conforming to subsurface geologic structures;

Step 2) described usual method comprises that the single shot record to collecting carries out static correction, NMO correction, velocity analysis, stack and migration processing.

3) carry out the linear encryption interpolation to adapt to the needs of wave-field reconstruction to discrete again according to recording geometry parameter and discrete field;

Described discrete of step 3) is p-and s-wave velocity field and density field.

4) rebuilding each wave field value on each net point constantly on discrete the basis according to following formula, and with each pure P wave-wave field and output of pure S wave-wave field at place, geophone station position constantly as this wave-field reconstruction record constantly;

In the formula: m=4 λ μ+4 μ ²N=λ+2 μ k=m ²-(2 λ μ) ², λ and μ are Lame's constant, just can obtain through p-and s-wave velocity and density conversion,

v _Xp, v _Xs, v _Yp, v _Ys, v _Zp, v _ZsBe speed component, obtain through solving an equation,

τ _Xx, τ _Yyτ _Zz, τ _Xy, τ _Xz, τ _YzBe the components of stress, obtain through solving an equation;

Wave field value on the described net point of step 4) comprises pure P wave-wave field and pure S wave-wave field.

5) will go up the record that obtains of step and do the processing identical, obtain stack and skew wave-field reconstruction section with real data;

6) stack that wave-field reconstruction is obtained and migrated section and field data collection are handled the stack and the migrated section that obtain and are compared, and confirm the form and the position of underground hydrocarbon reservoir structure.

The present invention is applicable to the wave-field reconstruction of any complex structure, and processing accuracy is high, efficient is high and frequency dispersion is low, is the method for very effective wave-field reconstruction and definite subterranean oil gas reservoir structure under the three-dimensional situation.

The record that the present invention obtains at wave-field reconstruction ripple in length and breadth separates fully, in follow-up wave field research, does not need to carry out wave field separation in length and breadth again.

Description of drawings

Fig. 1 is the wave-field reconstruction figure along the directions X Z component that P ripple that the present invention obtains is crossed focal point;

Fig. 2 is the wave-field reconstruction figure along the directions X Z component that S ripple that the present invention obtains is crossed focal point;

Fig. 3 is the real data stacked section;

Fig. 4 is the velocity field of real data;

Fig. 5 is that the present invention handles the stacked section that obtains.

Embodiment

The present invention proposes under the single order staggered-mesh three-dimensional in length and breadth wavelength-division separate wave-field reconstruction formula (shown in (1) formula), through to the finding the solution of (1) formula, can obtain the record v of pure compressional wave _p=v _Xp+ v _Yp+ v _ZpRecord v with pure shear wave _s=v _Xs+ v _Ys+ v _ZsIn the process of wave-field reconstruction, adopt the staggered-mesh method to find the solution, promptly find the solution six velocity of displacement (v earlier _Xp, v _Xs, v _Yp, v _Ys, v _Zp, v _Zs) to the partial derivative equation of time, use stress field in finding the solution; Then find the solution six stress (τ _Xx, τ _Yy, τ _Zz, τ _Xy, τ _Xz, τ _Yz) to the partial derivative equation of time, use the velocity of displacement field in finding the solution.Two the step solution procedure be interdependence.

Contain transformed wave in the pure wave record that obtains, it is different from the pure wave record (not containing the transformed wave composition) of pure compressional wave equation and pure shear wave equation wave-field reconstruction.Therefore, in follow-up wave field is handled, need not separate wave field, directly application of pure compressional wave and pure shear wave record is handled just passable.

The embodiment of the invention:

(1) the open-air actual recording geometry acquisition parameter of foundation is confirmed the reconstruction parameter in (actual acquisition parameter is consistent basically with field acquisition) wave-field reconstruction process, (comprising shot interval, distance between centers of tracks, track pitch, big gun number, road number, SI, road length, cautious X, Y coordinate and the corresponding elevation of big gun).

(2) read through early stage the seismic data data processing (comprising that the single shot record to collecting carries out a series of processing such as static correction, NMO correction, velocity analysis, stack and skew, is illustrated in figure 3 as the stack result that early stage, Data Processing obtained in somewhere, Xinjiang) obtain the interval velocity field of ripple in length and breadth and the density field that conform to this area's subsurface geologic structures.

(3) carry out interpolation to adapt to the needs of wave-field reconstruction to discrete again according to recording geometry parameter and discrete (p-and s-wave velocity field and density field are illustrated in figure 4 as the velocity of longitudinal wave field in area, Xinjiang).

(4) rebuild each wave field value on each net point (like Fig. 1-shown in Figure 2, the wave field of each Z component of directions X during for 500ms) constantly, velocity of displacement field: v according to formula (1) and discrete _Xp, v _Xs, v _Yp, v _Ys, v _ZpAnd v _ZsAnd to X component (v _x=v _Xp+ v _Xs), Y component (v _y=v _Yp+ v _Ys) and Z component (v _z=v _Zp+ v _Zs) wave field merge.Rebuild the normal stress τ on the every bit again _Xx, τ _Yy, τ _ZzWith shearing stress τ _Xy, τ _Xz, τ _YzSpeed component (v with each place, moment geophone station position _p=v _Xp+ v _Yp+ v _Zp, v _s=v _Xs+ v _Ys+ v _Zs) and the components of stress (τ _Xx, τ _Yy, τ _Zz, τ _Xy, τ _Xz, τ _Yz) as the wave-field reconstruction record of this each component constantly.

(5) will go up the wave-field reconstruction record that a step obtains and do the processing identical (comprising a series of processing such as static correction, NMO correction, velocity analysis, stack and skew) with real data; Obtain corresponding section (comprise stack and migrated section, be illustrated in figure 5 as the stack result that obtains after the wave-field reconstruction recording processing).

(6) section that wave-field reconstruction is obtained (stack and migrated section) is handled the section (stack and migrated section) that obtains with field data collection and is compared (like Fig. 3 and Fig. 5); Both consistance are high more good more, can well confirm underground hydrocarbon reservoir structure thus.

Fig. 1 is the wave-field reconstruction figure along the directions X Z component that P ripple that the present invention obtains is crossed focal point, and the time is 500ms.

Fig. 2 is the wave-field reconstruction figure along the directions X Z component that S ripple that the present invention obtains is crossed focal point, and the time is 500ms.

P ripple among Fig. 1 and Fig. 2 and the field addition of S wave-wave can be obtained all-wave field reconstruction figure, and this has just in time embodied unique distinction of the present invention.

Fig. 3 is the real data stacked section in somewhere, for the structural feature of confirming certain several the unknown in the section has designed velocity field as shown in Figure 4, has obtained stacked section shown in Figure 5 through a series of processing after wave-field reconstruction and the reconstruction.Through the relatively discovery of Fig. 3 and Fig. 5, it is very good that both coincide, and confirmed the subterranean oil gas reservoir structural feature of this area.

Claims (1)

1. the three-dimensional method of a definite subterranean oil gas reservoir structure is characterized in that the practical implementation step comprises:

1) open-air actual observation system acquisition data are confirmed the reconstruction parameter in the wave-field reconstruction process;

The described reconstruction parameter of step 1) comprises shot interval, distance between centers of tracks, track pitch, big gun number, road number, SI, road length, cautious X, Y coordinate and the corresponding elevation of big gun;

2) adopt usual way that geological data is carried out handling early stage interval velocity field of ripple in length and breadth and the density field that obtains conforming to subsurface geologic structures;

Step 2) described usual method comprises that the single shot record to collecting carries out static correction, NMO correction, velocity analysis, stack and migration processing;

3) carry out the linear encryption interpolation to adapt to the needs of wave-field reconstruction to discrete again according to recording geometry parameter and discrete field;

Described discrete of step 3) is p-and s-wave velocity field and density field;

4) rebuilding each wave field value on each net point constantly on discrete the basis according to following formula, and with each pure P wave-wave field and output of pure S wave-wave field at place, geophone station position constantly as this wave-field reconstruction record constantly;

$\left\{\begin{array}{c}{v}_x=v_{\mathrm{xp}}+v_{\mathrm{xs}}\\ v_y=v_{\mathrm{yp}}+v_{\mathrm{ys}}\\ v_z=v_{\mathrm{zp}}+v_{\mathrm{zs}}\\ \frac{{\∂v}_{\mathrm{xp}}}{\∂t}=\frac{\mathrm{mn}-4\mathrm{\λ\μn}}{k}{v}_p^2(\frac{{\∂\mathrm{\τ}}_{\mathrm{xx}}}{x}+\frac{{\∂\mathrm{\τ}}_{\mathrm{yy}}}{x}+\frac{{\∂\mathrm{\τ}}_{\mathrm{zz}}}{x})\\ \frac{{\∂v}_{\mathrm{yp}}}{\∂t}=\frac{\mathrm{mn}-4\mathrm{\λ\μn}}{k}{v}_p^2(\frac{{\∂\mathrm{\τ}}_{\mathrm{xx}}}{y}+\frac{{\∂\mathrm{\τ}}_{\mathrm{yy}}}{y}+\frac{{\∂\mathrm{\τ}}_{\mathrm{zz}}}{y})\\ \frac{{\∂v}_{\mathrm{zp}}}{\∂t}=\frac{\mathrm{mn}-4\mathrm{\λ\μn}}{k}{v}_p^2(\frac{{\∂\mathrm{\τ}}_{\mathrm{xx}}}{z}+\frac{{\∂\mathrm{\τ}}_{\mathrm{yy}}}{z}+\frac{{\∂\mathrm{\τ}}_{\mathrm{zz}}}{z})\\ \frac{{\∂v}_{\mathrm{xs}}}{\∂t}=v_s^2[\frac{1}{\mathrm{\μ}}(\frac{\∂{\mathrm{\τ}}_{\mathrm{xy}}}{y}+\frac{{\∂\mathrm{\τ}}_{\mathrm{xz}}}{z})+\frac{8\mathrm{\λ\μn}}{k}\frac{{\∂\mathrm{\τ}}_{\mathrm{xx}}}{x}-\frac{2n}{m+2\mathrm{\λ\μ}}\frac{{\∂\mathrm{\τ}}_{\mathrm{zz}}}{x}-\frac{2n}{m+2\mathrm{\λ\μ}}\frac{\∂{\mathrm{\τ}}_{\mathrm{yy}}}{x}]\\ \frac{{\∂v}_{\mathrm{ys}}}{\∂t}=v_s^2[\frac{1}{\mathrm{\μ}}(\frac{\∂{\mathrm{\τ}}_{\mathrm{xy}}}{x}+\frac{{\∂\mathrm{\τ}}_{\mathrm{yz}}}{z})+\frac{8\mathrm{\λ\μn}}{k}\frac{{\∂\mathrm{\τ}}_{\mathrm{yy}}}{y}-\frac{2n}{m+2\mathrm{\λ\μ}}\frac{{\∂\mathrm{\τ}}_{\mathrm{xx}}}{y}-\frac{2n}{m+2\mathrm{\λ\μ}}\frac{\∂{\mathrm{\τ}}_{\mathrm{zz}}}{y}]\\ \frac{{\∂v}_{\mathrm{zs}}}{\∂t}=v_s^2[\frac{1}{\mathrm{\μ}}(\frac{\∂{\mathrm{\τ}}_{\mathrm{xz}}}{x}+\frac{{\∂\mathrm{\τ}}_{\mathrm{yz}}}{y})+\frac{8\mathrm{\λ\μn}}{k}\frac{{\∂\mathrm{\τ}}_{\mathrm{zz}}}{z}-\frac{2n}{m+2\mathrm{\λ\μ}}\frac{{\∂\mathrm{\τ}}_{\mathrm{xx}}}{z}-\frac{2n}{m+2\mathrm{\λ\μ}}\frac{\∂{\mathrm{\τ}}_{\mathrm{yy}}}{z}]\\ \frac{{\∂\mathrm{\τ}}_{\mathrm{xx}}}{\∂t}=\mathrm{\λ}(\frac{{\∂v}_x}{\∂x}+\frac{\∂v_y}{y}+\frac{\∂v_z}{z})+2\mathrm{\μ}\frac{\∂v_x}{x}\\ \frac{{\∂\mathrm{\τ}}_{\mathrm{yy}}}{\∂t}=\mathrm{\λ}(\frac{{\∂v}_x}{\∂x}+\frac{\∂v_y}{y}+\frac{\∂v_z}{z})+2\mathrm{\μ}\frac{\∂v_y}{y}\\ \frac{{\∂\mathrm{\τ}}_{\mathrm{zz}}}{\∂t}=\mathrm{\λ}(\frac{{\∂v}_x}{\∂x}+\frac{\∂v_y}{y}+\frac{\∂v_z}{z})+2\mathrm{\μ}\frac{\∂v_z}{z}\\ \frac{{\∂\mathrm{\τ}}_{\mathrm{xy}}}{\∂t}=\mathrm{\μ}(\frac{\∂v_x}{\∂z}+\frac{\∂v_y}{x})\\ \frac{{\∂\mathrm{\τ}}_{\mathrm{xz}}}{\∂t}=\mathrm{\μ}(\frac{\∂v_x}{\∂z}+\frac{\∂v_z}{x})\\ \frac{{\∂\mathrm{\τ}}_{\mathrm{yz}}}{\∂t}=\mathrm{\μ}(\frac{\∂v_y}{\∂z}+\frac{\∂v_z}{y})\end{array}\right.---\left(1\right)$

In the formula: m=4 λ μ+4 μ ²N=λ+2 μ k=m ²-(2 λ μ) ², λ and μ are Lame's constant, just can obtain through p-and s-wave velocity and density conversion,

v _Xp, v _Xs, v _Yp, v _Ys, v _Zp, v _ZsBe speed component, obtain through solving an equation,

τ _Xx, τ _Yy, τ _Zz, τ _Xy, τ _Xz, τ _YzBe the components of stress, obtain through solving an equation;

Wave field value on the described net point of step 4) comprises pure P wave-wave field and pure S wave-wave field;

5) will go up the record that obtains of step and do the processing identical, obtain stack and skew wave-field reconstruction section with real data;

6) stack that wave-field reconstruction is obtained and migrated section and field data collection are handled the stack and the migrated section that obtain and are compared, and confirm the form and the position of underground hydrocarbon reservoir structure.

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