Velocity tomography using property scans
AssigneeExxonMobil Upstream Research Company
InventorJonathan Liu
Life of this patent
Estimating the term…
Abstract
Method for building a subsurface model of velocity or other elastic property from seismic reflection data using tomography. The method uses velocity scans to pick a focusing velocity model at each image point (40). The focusing velocities are used to pick depth errors from tables (60) generated using a tomographic inversion matrix (30) and a suite of different velocity models (10). The depth errors are then reconstructed at each image point from the velocity scans based on the difference between the base velocity model and the most coherent velocity from the scan (70). The reconstructed depth errors are used to compute the velocity model update (80).
Claims15
A scientific method for transforming seismic data into a subsurface physical property model, comprising:
- constructing the subsurface physical property model by performing tomographic inversion of the seismic data, using a computer, with residual depth errors reconstructed using property scanning;
- wherein the residual depth errors are reconstructed using the following relationship at each imaging point
- DA(vm−vf)
- where A is a matrix built from ray tracing, vm is a base migration model of the property, vf is a model of the property as picked from a property scan of migrated seismic data, and deviation operator D is defined by its operation on an arbitrary n-dimensional vector a={aj}:
- (
- Da
- )
- j
- =
- a
- j
- -
- ∑
- i
-
-
- a
- i
- n
- where indices i and j denote different source-receiver offsets among a total of n offsets present in the migrated seismic data.
A non-transitory computer usable medium having a computer readable program code embodied therein, said computer readable program code adapted to be executed to implement a scientific method for transforming seismic data into a subsurface physical property model, comprising:
- constructing the subsurface physical property model by performing tomographic inversion of the seismic data, with residual depth errors reconstructed using property scanning;
- wherein the residual depth errors are reconstructed using the following relationship at each imaging point
- DA(vm−vf)
- where A is a matrix built from ray tracing, vm is a base migration model of the property, vf is a model of the property as picked from a property scan of migrated seismic data, and deviation operator D is defined by its operation on an arbitrary n-dimensional vector a={aj}:
- (
- Da
- )
- j
- =
- a
- j
- -
- ∑
- i
-
-
- a
- i
- n
- where indices i and j denote different source-receiver offsets among a total of n offsets present in the migrated seismic data.
Dependencies are inferred from the claim text.