Method for extracting gravity anomaly by marine gravity survey

Abstract

The invention relates to a method for extracting gravity anomaly by a marine gravity survey, which comprises the following steps: computing transient course and navigational speed, adopting right-angle coordinate data within 4 seconds to compute the course and the navigational speed at an intermediate time point, and filtering out high-frequency interference; reading a gravity meter, the navigational speed, the course, water depth and tide, firstly performing 9-point smoothing to filtering out partial high-frequency interference, and then performing correcting computation on items; extracting gravity anomaly values at 10 seconds intervals for first 9-point smoothing; extracting 10-second integral multiple of gravity anomaly values for secondary 9-point smoothing; obtaining a final result of the effective and reasonable gravity anomaly value, thus eliminating high-frequency interference and the gravity anomaly in close relationship with density distribution of earthcrust. The method provided by the invention is applied to studies such as lithosphere, earthcrust structure, oil gas accumulation, and density anomalous body.

Description

technical field [0001] The invention provides a method for extracting gravity anomalies in marine gravity investigation, which belongs to the technical field of marine gravity exploration. Background technique [0002] Gravity exploration is to observe the gravity anomaly caused by the density change of the earth's lithosphere, and study the distribution and shape of density anomalies in the lithosphere accordingly. [0003] Marine gravity exploration uses ship-borne marine gravimeters to observe gravity anomalies. It is a continuous observation method of gravity anomalies under navigation, and it is carried out under dynamic conditions. [0004] In marine gravity exploration, due to the continuous change of the attitude of the ship, the position of the gravimeter in space changes accordingly, causing the change of the recorded value of the gravimeter. This change has nothing to do with the change of lithosphere density. It is an interference error and needs to be corrected ...

AI Technical Summary

Problems solved by technology

[0011] Among them, item (1) comes with the instrument and can only be eliminated within the allowable error range stipulated when the gravimeter leaves the factory.

Items (2) to (5) all have normative calculation methods. Since the parameters involved in the correction have errors, the calculation method is not completely consistent with the actual situation, resulting in imperfect corrections and errors.

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