System and method for seismic imaging
A method is described for seismic imaging that will produce a seismic image with correctly focused and positioned reflectors. This is accomplished by adding physical geological information to a beam tomography process to generate an updated earth model for the seismic imaging. The method may be executed by a computer system.
1. A computer-implemented method of seismic imaging for identification of and production from hydrocarbon reservoirs, comprising:
a. receiving, at a computer processor, a seismic dataset representative of a subsurface volume of interest;
b. receiving, at the computer processor, geological information for the subsurface volume of interest;
c. transforming, via the computer processor, the seismic dataset into a data beam set;
d. receiving, at the computer processor, an earth model;
e. computing, via the computer processor, traveltime variations from the data beam set based on the geological information and the earth model;
f. deriving, via the computer processor, an updated earth model based on the traveltime variations;
g. performing, via the computer processor, seismic imaging of the seismic dataset using the updated earth model to generate a seismic image with correctly focused and positioned reflectors; and
h. identifying geologic features based on the seismic image.
2. The method of claim 1 wherein the transforming the seismic dataset into the data beam set uses ray-tracing from surface locations to subsurface locations or subsurface locations to surface locations.
3. The method of claim 1 wherein the transforming the seismic dataset into the data beam set uses time shifts derived from ray-tracing in the earth model.
4. The method of claim 1 wherein the computing traveltime variations from the data beam set is based on physical data including at least one of well data and petrophysics data.
5. The method of claim 1 wherein the computing the traveltime variations from the data beam set is based on geological constraints and interpretations that conform to a structural evolution of the subsurface volume of interest.
6. The method of claim 1 wherein the computing the traveltime variations includes a similarity measurement between individual traces in the seismic dataset and a representative trace derived based on traces from the seismic dataset or a modeled dataset.
7. The method of claim 6 wherein the similarity measurement is one of cross-correlation, semblance, or dynamic warping.
8. The method of claim 1 wherein the computing the traveltime variations includes using a Monte Carlo approach to select the traveltime variations.
9. The method of claim 1 further comprising iterative repetitions of the transforming the seismic dataset, the computing the traveltime variation wherein the earth model received at the computer processor is the updated earth model from a previous iteration, the deriving the updated earth model, and the seismic imaging, until a maximum number of iterations is reached or similarity of traces is maximized.
10. The method of claim 1 wherein the computing the traveltime variations includes a measurement of traveltime difference, wherein the traveltime difference is the traveltime along ray-paths between initial image positions and desired image positions.
11. The method of claim 1 wherein the deriving the updated earth model comprises updating earth model parameters by distributing traveltime residuals along ray-paths.
12. The method of claim 1 further comprising updating the beam data set based on the updated earth model.
13. The method of claim 1 further comprising drilling at least one well based on the geologic features.
14. A computer system, comprising:
one or more processors;
memory; and
one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions that when executed by the one or more processors cause the system to:
a. receive, at a computer processor, a seismic dataset representative of a subsurface volume of interest;
b. receive, at the computer processor, geological information for the subsurface volume of interest;
c. transform, via the computer processor, the seismic dataset into a data beam set;
d. receive, at the computer processor, an earth model;
e. compute, via the computer processor, traveltime variations from the data beam set based on the geological information and the earth model;
f. derive, via the computer processor, an updated earth model based on the traveltime variations; and
g. perform, via the computer processor, seismic imaging of the seismic dataset using the updated earth model to generate a seismic image with correctly focused and positioned reflectors.
15. A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by an electronic device with one or more processors and memory, cause the device to
a. receive, at a computer processor, a seismic dataset representative of a subsurface volume of interest;
b. receive, at the computer processor, geological information for the subsurface volume of interest;
c. transform, via the computer processor, the seismic dataset into a data beam set;
d. receive, at the computer processor, an earth model;
e. compute, via the computer processor, traveltime variations from the data beam set based on the geological information and the earth model;
f. derive, via the computer processor, an updated earth model based on the traveltime variations; and
g. perform, via the computer processor, seismic imaging of the seismic dataset using the updated earth model to generate a seismic image with correctly focused and positioned reflectors.