Seismic method of performing the time picking step
US6868038B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 2001 |
| Grant date | Mar 15, 2005 |
| Priority date | — |
| Expiry date | Jul 20, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V2210/161
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention provides a method of performing the time picking step in a VSP (vertical seismic profile) survey. In a preferred embodiment of the invention the time picking step is carried out on a combined three-component amplitude of the received seismic energy, which contains the amplitude of all the seismic energy received at the receiver. The amplitude of the direct pulse in the combined trace will not decrease to zero as the offset of the source is changed, as can be the case for the single-component amplitude of the direct pulse. In a particularly preferred embodiment of the invention, the combined three-component amplitude is calculated by summing the Hilbert instantaneous amplitudes of the x-, y- and components of the seismic data using the equation (I). The present invention also provides two new time picks. One time pick involves finding the maximum positive gradient of A(t). The other time pick entails extrapolating to A(t)=0 from the time at which A(t) has its greatest positive gradient, using the maximum positive gradient for the extrapolation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.