Method for obtaining subsurface acoustic logging and synthetic seismogram by utilizing micro logging

Abstract

The invention discloses a method for obtaining subsurface acoustic logging and synthetic seismogram by utilizing micro logging. The method is characterized in that micro logging data in a time-depth domain are converted into acoustic logging records in a speed-depth domain by combining the characteristics of simplicity and fineness of micro logging subsurface construction and higher longitudinal resolution of acoustic logging, and utilizing the conversion relation between micro logging and acoustic logging data during seismic travel and stratum depths, and according to travel time informationof micro logging signals at different depths, so that the problem that a quaternary sedimentary loose soil layer medium cannot obtain acoustic logging record problems based on refracted wave first arrival under general conditions is solved; a superfacial reflection coefficient sequence is obtained by combining with density logging data; and the superfacial reflection coefficient sequence and selected high-frequency seismic wavelet are prepared into high-resolution superfacial synthetic seismogram for calibrating and constraining superfacial reflection seismic data.

Description

technical field [0001] The invention belongs to the field of geophysical seismic exploration, and relates to a method for obtaining shallow surface acoustic logging and synthetic seismic records by using seismic micro-logging, in particular, using micro-logging first-arrival time information to convert to obtain shallow surface fine velocity changes method. Background technique [0002] Seismic micro-logging technology was mainly used to investigate the near-surface geological structure in the past. It mainly uses a series of seismic sources with different depths to ground geophones with different first-arrival times of seismic waves to understand the thickness of the underground low-velocity zone and the depth of the water table. depth, but it is difficult to give fine surface velocity changes. [0003] Acoustic logging technology has a high vertical resolution and is widely used in oilfield exploration and development and engineering fields. However, in shallow surface ge...

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Problems solved by technology

[0002] Seismic micro-logging technology was mainly used to investigate the near-surface geological structure in the past. It mainly uses a series of seismic sources with different depths to ground geophones with different first-arrival times of seismic waves to understand the thickness of the underground low-velocity zone and the depth of the water table. depth, but difficult to give fine surface velocity variations

[0003] Acoustic logging technology has a high vertical resolution and is widely used in oilfield exploration and development and engineering fields. However, in shallow surface geophysical logging, the characteristics of the soft soil medium deposited in the Quaternary and its instrument response are the same as those of conventional rock medium. Significantly different logging characteristics, generally unavailable sonic logging based on refracted wave first arrivals

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