CN1158539C - Optimizing design method of 3D seismic observation system based on geologic geophysical model - Google Patents

Abstract

The present invention relates to a method of optimization design of a three-dimensional earthquake observing method based on a geologic geophysical model. The method comprises the steps that (A) a priori geologic geophysical model is established; (B) two or more types of observation systems of three-dimensional earthquake data acquisition are designed; (C) data acquisition is completed by the combined forward modeling of three-dimensional wave equation numerical simulation of a virtual spectral method and three-dimensional earthquake geophysical model simulation of a method; (D) depth migration before stacking is carried out on acquired data on the basis of a common reflective point, and some imaging results of earthquake treatment are obtained; (E) the imaging qualities of the imaging results of the earthquake treatment are comprehensively compared and evaluated, and one optimal earthquake imaging result is determined through comparison. The method has the advantages of wide range of application, and good applied effect, and the method has operation significance of guiding earthquake prospecting actual production of oil and natural gas, and enhancing oil-gas prospecting successful rate.

Description

Optimizing design method of 3 D seismic observation system based on geologic geophysical model

Technical field

The present invention relates to a kind of technical design optimization method of 3-d seismic exploration in petroleum gas and other mineral resources and the Geological Engineering, particularly a kind of optimizing design method of 3 D seismic observation system based on geologic geophysical model.

Background technology

Seismic prospecting three big links are to gather, handle and explain.Collection is the basis; The receiving system that activating system that epicenter excitation point position is formed on the ground and wave detector acceptance point position are formed must be by correct geometric distributions, and promptly the seismic observation system of You Huaing just can collect effectively complete subsurface geological structure information.Therefore, recording geometry plays an important role in seismic prospecting, and its design quality is directly connected to the success or failure of exploration task.Because the 3-D seismics workload is big, investment is high, three-dimensional work area often is arranged in the complex structure area again, so the stereo observing system optimal design is important doubly just.

So far, both at home and abroad mostly the stereo observing system design software that widely adopts is based on horizontal layer geologic model and common midpoint (CMP) superposition principle, and they are not suitable for the 3-D seismics technical design on complex structure, high spud angle stratum.Under the complex structure situation, use this class design proposal, not only can not obtain high-quality seismic imaging, even the seismic imaging result that may make mistake.

Summary of the invention

Therefore, purpose of the present invention makes provides a kind of optimizing design method of 3 D seismic observation system based on geologic geophysical model.

This method is based on the three-dimensional geological and the geophysical model of exploratory area priori, adopt numerical simulation and physical simulation to unite positive artistic skills art, according to common reflection point (CRP) principle, be imaged as evaluation criterion with the earthquake of geologic objective high-quality, the image quality of three-dimensional seismic acquisition techniques design proposal and geological data processing is contacted directly, realized optimizing stereo observing system with this and design this acquisition technique target.

Optimizing design method of 3 D seismic observation system based on geologic geophysical model provided by the invention may further comprise the steps:

A) according to the existing exploration achievement in exploratory area, promptly complex geological structure and complicated geological volume morphing and geophysical parameters thereof are set up the geologic geophysical model of priori; B) be exploration targets with above-mentioned geologic geophysical model, design the recording geometry that two or more 3D seismic datas are gathered; C) with this model as the 3-D seismics object of observation, design desired technical parameter and construction figure in the open-air earthquake data acquisition process of laboratory simulation according to recording geometry, obtain the open-air original seismic data of simulation, the concrete practice is to adopt the simulation of the three-dimensional fluctuation of empty spectrometry equation number value just drilling with two kinds of method associatings of 3-D seismics physical model simulation to finish this data collection task; D) data of gathering are carried out 3D seismic data and handle,,, obtain earthquake and handle several imaging results the data preceding depth shift processing that change wherein based on common reflection point; E) with the geologic geophysical model of priori as estimating and contrast standard, with signal to noise ratio (S/N ratio), resolution and structural feature feature as the technical Analysis main contents, the comprehensive comparative evaluation that several imaging results are carried out image quality is handled in earthquake, through contrast, determine one of them best earthquake imaging results.

Step e wherein) also comprise:

E1) if imaging results does not also reach the target call of seismic prospecting, then revise original stereo observing system parameter, again carry out the work of 3D seismic data acquisition process subsequently, described stereo observing system parameter comprises 3-D seismics observation width degree, bin size, covering or illumination number of times, illuminance, seismic trace sum, maximum offset, wherein observes width degree N be defined as:

$N=\frac{\mathrm{\θ}}{2\mathrm{\π}}(C_1\frac{L_c}{L_i}+C_2\frac{n_c}{n_i})$

Wherein: L _c/ L _iThe horizontal vertical ratio of-arrangement sheet,

n _c/ n _iThe horizontal vertical ratio of-degree of covering,

C ₁-with arrange the relevant coefficient of the horizontal vertical ratio of sheet,

C ₂-with the relevant coefficient of the horizontal vertical ratio of degree of covering, and C ₂=1-C ₁, generally get C ₁=C ₂=0.5,

θ-center, subarea bin azimuthal distribution scope (radian);

E2), then export 3 D seismic observation system optimal design process flow diagram if imaging results has reached the target call of seismic prospecting.

The present invention is described in detail below in conjunction with accompanying drawing, so that the advantage of further understanding above-mentioned purpose of the present invention, characteristics and bringing thus.

Description of drawings

Fig. 1 is the process flow diagram of the optimizing design method of 3 D seismic observation system based on geologic geophysical model of the present invention;

Fig. 2 (a) is the Qianmiqiao buried hill structural physical model according to the priori data make;

Fig. 2 (b) is the two dimension 337 survey line log sheets that North and South direction is passed the top, buried hill;

Fig. 3 adopts the three-dimensional Wave equation forward modeling of empty spectrometry respectively and adopts the resulting seismologic record of three-dimensional seismic physical simulation on 337 surveys line;

Fig. 4 is the horizontal superposition imaging results of geological data (337 line) that three kinds of recording geometrys are gathered, and wherein Fig. 4 (a) is vertical 1 recording geometry of 24 horizontal strokes of 8 lines, 2 big guns; Fig. 4 (b) is vertical 2 recording geometrys of 24 horizontal strokes of 8 lines, 4 big guns; Fig. 4 (c) is vertical 2 recording geometrys of 24 horizontal strokes of 8 lines, 8 big guns;

Fig. 5 is the earthquake data offset imaging results (the dropping cut slice figure of cima top imaging) of different width degree three-dimensional acquisitions, and wherein, Fig. 5 (a) is the earthquake data offset of narrow three-dimensional acquisition, and Fig. 5 (b) is the earthquake data offset of wide three-dimensional acquisition.

Embodiment

It is target since 1996 at exploratory area concrete complex geological structure that physical prospecting key lab of China National Petroleum Corporation (CNPC) explored a kind of, based on the CRP seismic imaging, new three-dimensional acquisition technical design method, this method workflow as shown in Figure 1.

At first set up the geologic geophysical model of priori, set up the seismic velocity model of underground medium usually according to the existing exploration achievement in exploratory area (complex geological structure and complicated geological volume morphing and geophysical parameters thereof); Second step was an exploration targets with above-mentioned geologic geophysical model, designed the recording geometry that two or more 3D seismic datas are gathered; The 3rd goes on foot with this model as the 3-D seismics object of observation, design desired technical parameter and construction figure in the open-air earthquake data acquisition process of laboratory simulation according to recording geometry, this method characteristics are to adopt mathematical computations and two kinds of methods of Physical Experiment to simulate open-air earthquake construction, obtaining the open-air original seismic data (referring to Fig. 3) of simulation, specifically is to adopt the simulation of the three-dimensional fluctuation of empty spectrometry equation number value just drilling with two kinds of method associatings of 3-D seismics physical model simulation to finish this data collection task; The 4th step was the data of gathering to be carried out 3D seismic data handle, and handling principle is based on common reflection point (CRP), and core technology is repeatedly preceding depth shift processing, i.e. a kind of seismic imaging technology of current popular, thus obtaining earthquake handles several imaging results; The 5th step with the geologic geophysical model of priori as estimating and contrast standard, with signal to noise ratio (S/N ratio), resolution and structural feature feature as the technical Analysis main contents, the comprehensive comparative evaluation that several imaging results are carried out image quality is handled in earthquake, through contrast, determine one of them best earthquake imaging results; If this imaging results does not also reach the target call of seismic prospecting, then to revise original stereo observing system parameter (design proposal), carry out the work of 3D seismic data acquisition process subsequently again; If this imaging results has reached the target call of seismic prospecting, then its pairing stereo observing system is exactly the end product of this area's 3-d seismic exploration optimal design, exports 3 D seismic observation system optimal design workflow diagram subsequently.At this moment, whole optimal design work also declares to be finished simultaneously.

The 3 D seismic observation system main design contents is that three-dimensional observation template (several lines, a few process of preparing Chinese medicine) is selected and the stereo observing system parameter designing.The stereo observing system parameter mainly contains 3-D seismics observation width degree, bin size, covering or illumination number of times, illuminance, seismic trace sum, maximum offset etc.When definite 3-D seismics is observed width degree N, the following formula that utilizes the applicant to propose:

$N=\frac{\mathrm{\θ}}{2\mathrm{\π}}(C_1\frac{L_c}{L_i}+C_2\frac{n_c}{n_i})$

Wherein: L _c/ L _IThe horizontal vertical ratio of-arrangement sheet,

n _c/ n _IThe horizontal vertical ratio of-degree of covering,

C ₁-with arrange the relevant coefficient of the horizontal vertical ratio of sheet,

C ₂-with the relevant coefficient of the horizontal vertical ratio of degree of covering, and C ₂=1-C ₁, generally get C ₁=C ₂=0.5,

θ-center, subarea bin azimuthal distribution scope (radian).

When: N＜0.5 is narrow orientation recording geometry;

N 〉=0.5 o'clock is the wide-azimuth recording geometry;

N 〉=0.85 o'clock is the omnibearing observation system;

Oil-gas exploration task in conjunction with China the western and eastern complex area, physical prospecting key lab of China National Petroleum Corporation (CNPC) (CNPC) repeatedly is applied to this method in the actual 3-D seismics technical design, huge port Qianmiqiao buried hill model for example, the contrary zone of fracture model of covering in car row area, Xinjiang, Xinjiang Yi Qikelike fold thrust belts model, the complex fault block models of Jurong, Jiangsu and Hongze etc. have all been obtained good effect.Be example with huge port Qianmiqiao buried hill structure 3 D seismic observation system optimal design below, this method is done simple the introduction.

Fig. 2 (a) is the Qianmiqiao buried hill structural physical model according to the priori data make, and Fig. 2 (b) passes the two dimension 337 survey line log sheets at top, buried hill for North and South direction.Fig. 3 adopts the three-dimensional Wave equation forward modeling of empty spectrometry respectively and adopts the resulting seismologic record of three-dimensional seismic physical simulation on 337 surveys line, relatively these two records can think that both are similar.Adopted several different recording geometrys to carry out the 3D seismic data collecting work to this area,, obtained different seismic imaging result (seeing Fig. 4 and Fig. 5) by handling.Subsequently with geologic objective as standard, various imaging results are estimated, optimize the recording geometry design.For example the signal noise ratio (snr) of image of Fig. 4 (c) should think then that than the height of Fig. 4 (b) and Fig. 4 (a) the corresponding recording geometry of Fig. 4 (c) is wherein best; For example the top imaging of Fig. 5 (b) cima is relatively good again, and focusing quality is than Fig. 5 (b) height, and explanation should select the wide-azimuth stereo observing system to carry out the earthquake construction.Some above-mentioned practical applications show: this method scope of application is extensive, and effect is good, has realistic meaning to instructing petroleum gas seismic prospecting actual production, raising oil-gas exploration success ratio.

Claims (1)

1, a kind of optimizing design method of 3 D seismic observation system based on geologic geophysical model may further comprise the steps:

A) according to the existing exploration achievement in exploratory area, i.e. complex geological structure and complicated geological volume morphing and geophysical parameters thereof are set up the geologic geophysical model of priori;

B) be exploration targets with above-mentioned geologic geophysical model, design the recording geometry that two or more 3D seismic datas are gathered;

C) with this model as the 3-D seismics object of observation, design desired technical parameter and construction figure in the open-air earthquake data acquisition process of laboratory simulation according to recording geometry, obtain the open-air original seismic data of simulation, the concrete practice is to adopt the simulation of the three-dimensional fluctuation of empty spectrometry equation number value just drilling with two kinds of method associatings of 3-D seismics physical model simulation to finish this data collection task;

D) data of above-mentioned collection are carried out 3D seismic data and handle,,, obtain earthquake and handle several imaging results the data of the gathering preceding depth shift processing that change wherein based on common reflection point;

E) with the geologic geophysical model of priori as estimating and contrast standard, with signal to noise ratio (S/N ratio), resolution and structural feature feature as the technical Analysis main contents, the comprehensive comparative evaluation that several imaging results are carried out image quality is handled in described earthquake, through contrast, determine one of them best earthquake imaging results; Step e wherein) also comprise:

E1) if imaging results does not also reach the target call of seismic prospecting, then revise original stereo observing system parameter, again carry out the work of 3D seismic data acquisition process subsequently, described stereo observing system parameter comprises 3-D seismics observation width degree, bin size, covering or illumination number of times, illuminance, seismic trace sum, maximum offset, wherein observes width degree N be defined as:

$N=\frac{\mathrm{\θ}}{2\mathrm{\π}}(C_1\frac{L_c}{L_i}+C_2\frac{n_c}{n_i})$

Wherein: Lc/Li-arranges the horizontal vertical ratio of sheet,

The horizontal vertical ratio of nc/ni-degree of covering,

C1-and the relevant coefficient of the arrangement horizontal vertical ratio of sheet,

C2-and the relevant coefficient of the horizontal vertical ratio of degree of covering, and C2=1-C1 generally get C1=C2=0.5,

θ-center, subarea bin azimuthal distribution scope (radian);

E2), then export 3 D seismic observation system optimal design process flow diagram if imaging results has reached the target call of seismic prospecting.

Images