Nonlinear inversion method and system for quality factor q based on simulated annealing

A technology of simulated annealing method and quality factor, which is used in seismology, instruments, measuring devices, etc., can solve problems such as large errors, and achieve the effect of reducing difficulty, improving accuracy and stability, and improving reliability.

Active Publication Date: 2021-02-19
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
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Problems solved by technology

In this case, the attenuation curve is no longer a linear function of frequency, but presents a nonlinear attenuation trend, so the conventional method for calculating Q value will have a large error and is no longer suitable for frequency-dependent Q Finding the value

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  • Nonlinear inversion method and system for quality factor q based on simulated annealing
  • Nonlinear inversion method and system for quality factor q based on simulated annealing
  • Nonlinear inversion method and system for quality factor q based on simulated annealing

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Effect test

Embodiment 1

[0079] Embodiment 1: model test

[0080] In order to prove the correctness and effectiveness of the method, and to show that the method has higher accuracy, a model experiment is used to illustrate below.

[0081] Such as figure 1 As shown, a two-well micro-logging observation system with one shot excitation and two reception channels is designed. Assume a near-surface depth of 4 meters. The depth of the excitation well is 20 meters, and the bottom of the well is used for excitation, and the excitation depth is 20 meters. The depth of the receiving well is 4 meters, and a geophone of the same type is installed at the wellhead and the bottom of the well. The well spacing is 4 meters.

[0082] Such as figure 2 As shown, the design model is that the velocities of the low-velocity layer and the deceleration layer are respectively v 1 =450m / s,v 2 =1300m / s; the quality factors of the low-velocity layer and the decelerating layer are respectively (i.e. Q -1 (f 0 )=0.2, f ...

Embodiment 2

[0086] Example 2: Actual Data

[0087] Such as Figure 6 As shown, this embodiment is an application example of block A of an oil field. The terrain in this area is flat, and the near-surface structure is relatively simple. It is divided into two sets of strata, the low-velocity layer and the velocity-reducing layer. The thickness of the low-velocity layer is about 4 meters, and the thickness of the velocity-reducing layer is more than 40 meters. In the stimulation well, the minimum depth of the stimulation well is 2 meters, the maximum depth of the stimulation well is 16 meters, the depth of the shot point is 2 meters apart, and a total of 8 shots are fired. In the receiving well, a geophone of the same type is arranged at the wellhead and the bottom of the well respectively. Well spacing is 4m. The invention extracts 16 meters from the bottom of the well for excitation, and the two channels received by the well head and the bottom of the well carry out nonlinear inversion...

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Abstract

The present invention proposes a quality factor Q nonlinear inversion method and system based on simulated annealing. The method includes: using a double-well micro-logging observation system to obtain micro-logging data; extracting the same shot from the micro-logging data Calculate the attenuation curve of the excited direct wave; by introducing the prior information that the quality factor Q changes with frequency, establish a nonlinear objective function based on the attenuation curve; use the simulated annealing method to nonlinearly invert the parameters in the objective function, and then Find the quality factor Q value that varies with frequency. Compared with the existing technology, the constant Q assumption is avoided, and the frequency-varying Q value is directly calculated, which is conducive to accurately compensating the energy lost by formation absorption, and provides a data basis for high-precision imaging. This method eliminates the error introduced by the inversion method based on the constant Q assumption in the traditional method, and improves the accuracy of Q value calculation. The method utilizes micro-logging data to improve the accuracy and stability of the results.

Description

technical field [0001] The invention relates to the technical field of geophysical exploration, and specifically designs a near-surface Q value modeling technology using simulated annealing nonlinear inversion, which can be applied to seismic data processing in petroleum geophysical exploration. Background technique [0002] Due to the viscoelastic effect of the formation, seismic waves will experience frequency absorption and phase distortion during propagation, which seriously reduces the resolution of seismic data. The quality factor Q can quantitatively describe the attenuation. The resolution and energy of seismic data can be restored by calculating the Q value accurately and using inverse Q filtering. Therefore, how to obtain the Q value accurately is the key. [0003] At present, the calculation method of Q value is based on the assumption of constant Q, that is, it is assumed that Q does not change with frequency, and the spectral ratio method is the most commonly ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01V1/30
CPCG01V1/306G01V2210/6169G01V2210/624G01V2210/66
Inventor 郑浩蔡杰雄郭恺王守进
Owner CHINA PETROLEUM & CHEM CORP
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