Method for microearthquake positioning and anisotropic speed structure tomography

A technology of anisotropy and imaging method, applied in seismology, seismic signal processing, geophysical measurement, etc., can solve the problems of non-inversion, azimuth anisotropy, large error of underground medium model, etc.

Inactive Publication Date: 2018-07-06
HOHAI UNIV
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

This method does not invert the microseismic initiation time, which is also crucial to describe the fracture development process.
In addition, the cracks generated during the fracturing process will produce azimuth anisotropy, and the error of the underground medium model described by VTI medium is relatively large

Method used

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  • Method for microearthquake positioning and anisotropic speed structure tomography
  • Method for microearthquake positioning and anisotropic speed structure tomography
  • Method for microearthquake positioning and anisotropic speed structure tomography

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Embodiment 1

[0133] Embodiment 1 is a calculation example of a microseismic positioning and anisotropic velocity structure tomography method proposed by the present invention, and its specific calculation results are further disclosed as follows:

[0134] like Figure 4 As shown, the triangle and the dot represent the geophone and the seismic source respectively, and the black plane is the layer interface, which is the model established in Embodiment 1 of the present invention, which is a four-layer horizontally layered anisotropic TI medium. The anisotropic elastic modulus parameters of the four layers from top to bottom are C 11,1 =20.011,C 13,1 =7.505,C 33,1 =16.403,C 44,1 =5.588,C 66,1 =7.15; C 11,2 =22.821,C 13,2 =8.364,C 33,2 =18.404,C 44,2 =6.4,C 66,2 =7.937; C 11,3 =18.478,C 13,3 =6.145,C 33,3 =13.19,C 44,3 =5.198,C 66,1 =7.278; C 11,4 =23.800,C 13,4 =8.693,C 33,4 =19.193,C 44,4 =7.198,C 66,4 =8.35. The unit of elastic modulus parameter is km 2 ·s -2 . The an...

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Abstract

The invention discloses a method for microearthquake positioning and anisotropic speed structure tomography. The method comprises the following specific steps that 1, an initial model is read, and parameters are inversed; 2, theoretical travel time and a ray path of a microearthquake event are calculated in an anisotropic medium; 3, first-order partial derivatives about to-be-inversed parameters when the anisotropic speed structure and microearthquake event parameters of an underground medium are inversed at the same time are calculated; 4, a chromatography equation set for inversing the anisotropic speed structure and the microearthquake event parameters of the underground medium is established; 5, the chromatography equation set is solved through a sub-space method, and updating values of microearthquake source parameters and the anisotropic speed structure of the medium are obtained; 6, an anisotropic speed structure model and the earthquake source parameters are updated and restrained; 7, iteration judgement is stopped. According to the method, for a horizontal layered anisotropic TI medium, by using ground and in-well observation travel time data, the earthquake source parameters and the anisotropic speed structure of the medium can be inversed at the same time.

Description

technical field [0001] The invention belongs to the technical field of microseismic monitoring, in particular to a method for microseismic positioning and anisotropic velocity structure tomography. Background technique [0002] Hydraulic fracturing technology is one of the important measures to increase production in the development of unconventional oil and gas resources, such as tight sandstone gas, shale gas and coalbed methane. Microseismic detection technology mainly describes and characterizes the fracture network and estimates the reservoir volume of fracturing stimulation by locating and analyzing microseismic events, which plays an important role in hydraulic fracturing analysis. However, in addition to the error in first arrival time picking, the lack of accurate subsurface velocity model description is another key factor affecting the accuracy of microseismic positioning. In traditional microseismic location, velocity models are constructed from well logs and cal...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V1/28G01V1/30
CPCG01V1/282G01V1/288G01V1/30G01V1/303G01V1/306G01V2210/1232G01V2210/1234G01V2210/6222G01V2210/6242G01V2210/626G01V2210/65
Inventor 黄国娇巴晶曹青业何润发戚慧庞孟强钱卫
Owner HOHAI UNIV
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