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Method for determining longitudinal wave speed and transverse wave speed of coalbed gas

A technology of shear wave velocity and longitudinal wave velocity, applied in the field of exploration data processing, can solve problems such as difficulty in determining the velocity of longitudinal wave and shear wave, failure of parameter regression, and complex relationship

Active Publication Date: 2015-04-15
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional multiple regression method needs to assume a functional relationship first, but for the longitudinal wave and shear wave propagating in coalbed methane, its velocity is affected by rock physical properties and gas saturation, etc., the relationship is very complicated, and it is difficult to pre-define this function relationship, which often leads to parameter regression failure, and cannot accurately determine the relationship between the longitudinal wave and shear wave velocity of coalbed methane, making it difficult to determine the longitudinal wave and shear wave velocity

Method used

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  • Method for determining longitudinal wave speed and transverse wave speed of coalbed gas
  • Method for determining longitudinal wave speed and transverse wave speed of coalbed gas
  • Method for determining longitudinal wave speed and transverse wave speed of coalbed gas

Examples

Experimental program
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specific Embodiment approach

[0039] 1) Collect seismic exploration and logging data, and obtain L group shear wave velocity y and shear wave velocity x after processing (the same below);

[0040] 2) According to the formula (1), the average value of y and x is zero;

[0041] 3) Normalize y and x according to formula (2);

[0042] 4) Calculate the initial value φ of the optimal transformation of x and y according to formula (3) respectively 0 (x) and θ 0 (y):

[0043] 5) Find the best transformation φ of x and y for the kth iteration according to formula (4) k (x) and θ k (y);

[0044] 6) Calculate the error of two adjacent iterations according to formula (5),

[0045] 7) Repeat steps 5) and 6) until the error of two adjacent iterations satisfies formula (6), then the best transformation function θ(y) of shear wave velocity y and the best transformation function φ(y) of longitudinal wave velocity x are obtained. x)

[0046] 8) Use the linear regression method to regress the function values ​​of the...

specific example

[0049] 1) Obtain pre-stack seismic records and logging records, and obtain shear wave velocity y and shear wave velocity x after processing;

[0050] figure 1 It is a scatter diagram of the shear wave velocity and the longitudinal wave velocity of the experimental well of the present invention, and the present invention is the most experimental example. The straight line in the figure represents the linear fitting relationship, and it can be seen that the correlation coefficient is 0.889.

[0051] 2) According to step (2) - step (3), preprocess y and x to obtain the shear wave and longitudinal wave velocity after the average value is zero and normalized;

[0052] 3) Obtain the optimal transformation of y and x according to step (4)-step (7);

[0053] figure 2 is the scatter diagram of the best transformation of the shear wave velocity and the shear wave velocity of the experimental well of the present invention, image 3 It is the scatter diagram of the optimum transformati...

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Abstract

The invention belongs to an exploration data processing process, and discloses a method for determining a longitudinal wave speed and a transverse wave speed of a coalbed gas. The longitudinal wave speed and the transverse wave speed are obtained after earthquake exploration and logging data is processed, processing is performed on the longitudinal wave speed and the transverse wave speed respectively, average values are enabled to be zero respectively, nominalization processing is performed on the longitudinal wave speed and the transverse wave speed of a certain group, optimum transformation of the longitudinal wave speed and the transverse wave speed are solved, optimum transformation function values are obtained through an iteration, a function relational expression is obtained through regression, and according to the function relational expression, the transverse wave speed or the longitudinal wave speed of other wells or other regions is obtained. According to the invention, the defect is overcome that a conventional multi-element regression method requires a function relation to be assumed in advance, the mutual relation between the longitudinal wave speed and the transverse wave speed of the coalbed gas after the regression can be effectively improved, and the transverse wave speed or the longitudinal wave speed of said other wells or said other regions can be obtained by use of the obtained relation between the transverse wave speed or the longitudinal wave speed and the transverse wave speed.

Description

technical field [0001] The invention relates to geophysical exploration technology, belongs to the exploration data processing process, and is a method for determining the longitudinal wave and shear wave velocity of coal bed gas by using the optimal transformation method. Background technique [0002] With the development of the energy industry, more and more attention has been paid to the exploration and development of coalbed methane, which poses new challenges for geophysical prospecting and well logging technology. Due to the huge difference between coalbed methane and conventional natural gas in terms of generation and storage, many formulas and research methods for natural gas reservoirs are no longer applicable in the description and research of coalbed methane reservoirs, which prompts people to adopt new methods to study coalbed methane . [0003] In recent years, research on coalbed methane reservoirs has gradually increased. When looking for an empirical formula...

Claims

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Application Information

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IPC IPC(8): G01V1/28
Inventor 马光凯孙鹏远钱忠平任晓乔黄燕
Owner BC P INC CHINA NAT PETROLEUM CORP
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