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Earthquake stratum fracture crack density retrieval method and system

A fracture density and fissure technology, which is applied in the field of seismic stratigraphic fissure and fracture density inversion methods and systems, can solve problems such as the quantitative evaluation of fractured oil and gas reservoirs that cannot meet the requirements for calculating oil and gas reserves in fractured oil and gas reservoirs.

Active Publication Date: 2014-01-15
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, neither the travel time difference of the split shear wave nor the ratio of the major and minor axes of the longitudinal wave ellipse can only give the relative size of the fracture density in the formation (that is, the degree of development), which cannot meet the quantitative evaluation of the formation permeability and the oil and gas reserves of fractured reservoirs. computing requirements

Method used

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  • Earthquake stratum fracture crack density retrieval method and system
  • Earthquake stratum fracture crack density retrieval method and system
  • Earthquake stratum fracture crack density retrieval method and system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0060] This example is a three-layer geological model with faults, the model size is 1000m×800m; the grid size is: DX=DZ=10m, the fault drop is 10m, the upper and lower layers are the same, the middle layer has developed cracks, and the thickness of the cracked layer Is 30m, the crack direction and x 1 The axes are parallel, and the model parameters are shown in Table 1:

[0061] Layer number

λ(GPa)

μ(GPa)

ρ(g / cm 3 )

e

Vp(m / s)

Tier 1

13.087

11.454

2.4

0.0

3870

[0062] Layer 2

10.116

5.734

2.3

0.08

3060

Layer 3

13.087

11.454

2.4

0.0

3870

[0063] Table 1

[0064] The corresponding model diagram is as Figure 1a , Figure 1b as well as Figure 1c Shown. The depth direction of the fracture density rock changes as figure 2 As shown by the solid line, fissures are developed near the fault, and the density of fissures on both sides gradually decreases, such as image 3 Shown by the solid line.

[0065] Such as Figure 4 As shown, this embodiment is a flow chart of a me...

Embodiment 2

[0161] It is a five-layer geological model, and the model size and grid size are the same as in the first embodiment. The third layer and the fourth layer are developed with cracks. The crack density of the third layer is 0.12, and the crack direction is the same as x 1 The axis angle is -350, the crack density of the fourth layer is 0.06, and the crack direction is x 1 The shaft angle is -750, the model of Example 2 is as Figure 7 As shown, the corresponding parameters are shown in Table 2.

[0162] Layer number

Thickness(m)

ρ(g / cm 3 )

V p(m / s)

Vs(m / s)

e

θ (degree)

1

400

2400

3640

1750

0

0

2

70

2300

3157

1579

0

0

3

50

2450

3513

1887

0.12

-35

4

80

2500

3726

2053

0.06

-75

5

600

2400

3640

1750

0

0

[0163] Table 2

[0164] Three-component seismic data of 30 shots were collected on the model, Figure 8 Perform inversion for the data of a certain shot, and the specific implementation steps are basically the same as those in the first embodiment. The differences ar...

Embodiment 3

[0170] Such as Picture 10 Shown is a structural diagram of a seismic formation crack density inversion system of the present invention, including the following units:

[0171] The preprocessing unit 1001 is configured to collect three-component seismic data and preprocess the three-component seismic data to obtain measured three-component shot set data;

[0172] The pre-processing of the three-component seismic data includes: two horizontal component rotation, three-component static correction, surface consistent amplitude compensation and pre-stack noise removal.

[0173] The depth domain longitudinal wave velocity and formation mass density calculation unit 1002 is used to extract common center point gather data from the vertical component shot collection data in the three-component shot collection data, and perform longitudinal wave velocity analysis, time domain longitudinal wave velocity calculation and longitudinal wave Time-depth conversion to obtain the longitudinal wave vel...

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Abstract

The invention provides an earthquake stratum fracture crack density retrieval method and system. Collected earthquake wave information is fully used through full-waveform retrieval, the propagation behavior of earthquake waves underground is automatically considered, and high-accuracy earthquake retrieval results can be given. Through the elastic full-waveform retrieval theory in HTI media, the full-waveform fracture crack density retrieval method is provided, and quantitative forecast of earthquake underground stratum fracture crack density is achieved.

Description

Technical field [0001] The invention relates to the field of seismic exploration, in particular to a method and system for inverting the density of fractures in seismic formations. Background technique [0002] Fissures are the storage space and percolation channel for oil and gas, as well as the places where water and coalbed methane are enriched, stored and migrated. Proving the distribution and development of underground fissures is essential for oil and gas prediction, improvement of oil and gas productivity, prevention of gas explosion, roof / floor water inrush, and coalbed methane development. [0003] The parameters describing the distribution and development of fissure fractures mainly include the direction of fissures and the density of fissures. At present, seismic methods mainly include transverse wave splitting method and polarization map method, longitudinal wave azimuth AVOA method and azimuth travel time method. In theory, shear waves are more sensitive to the exist...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V1/28G01V1/30
Inventor 石玉梅
Owner PETROCHINA CO LTD
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