Method to complement lost stratum under shaft

Abstract

Provided is a method to complement a lost stratum under a shaft. The method improves inversion efficiency and the accuracy rate. The method includes the steps of confirming mutually linked and sealed geological blocks according to reflection characteristics of earthquake reflection waves and geological data, allocating shaft data to the geological blocks according to tracks of the measured shaft, confirming the position of a crossed contact point formed when the shaft penetrates through a section of a normal fault according to all the tracks of the shaft in a work area, calculating thicknesses of an upper stratum and a lower stratum and the position and the thickness of the lost stratum at the crossed contact point, confirming structure characteristics of the lost stratum, rebuilding a stratum sequence section close to the lost stratum to complement the lost stratum, and carrying out earthquake inversion with a result as an original value and a restraint condition of the inversion. The geological characteristics of the upper stratum and the lower stratum are effectively used, the lost stratum is built, on the basis that known data with various sources are fully made use of, lost data are predicted, the result conforms to the geological characteristics, and precise description for change conditions of internal physical properties of a target stratum is benefited in the earthquake inversion.

Description

technical field [0001] The invention belongs to the field of petroleum and natural gas exploration and development, aims to use computer technology to invert and estimate the spatial distribution and internal physical property change characteristics of the target layer based on seismic data and stratum geological data, and provides a supplementary underground missing stratum to constrain the seismic response Deduce the method of accurately predicting the change law of formation wave impedance, and serve for reservoir prediction and oilfield development. Background technique [0002] Geophysical inversion is a method of using observed data to infer the spatial distribution of strata and the change of physical properties inside the stratum. If only ground-observed seismic data are used for inversion, the prediction results will have large errors and low computational efficiency. In order to solve this problem, combined with the structural interpretation results of the target ...

AI Technical Summary

Problems solved by technology

If an oil reservoir is found near a normal fault and a well site is arranged to drill the normal fault, there will be missing formation information on both sides of the section during logging data collection and lithology data collection. Distortion will appear on the established attribute control points, such as figure 1 As shown, this leads to the failure of the inversion method to predict the physical property change of the target layer

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