US 8,265,913 B2 · Electromagnetic surveying

Abstract

A method of analysing results from a controlled source electromagnetic survey of a region of interest containing a previously identified geological structure suitable for bearing hydrocarbons is described. The method comprises providing a first survey data set obtained outside the region of interest, i.e. off-target, for a range of source-receiver orientations and offsets, and providing a second survey data set obtained inside the region of interest, i.e. on target, for a range of source-receiver offsets. The method further comprises performing a mathematical inversion of the first survey data set to provide a model of the subterranean strata outside the region of interest, and processing the second survey data set to provide a model of the subterranean strata inside the region of interest, wherein the processing of the second survey data set takes account of the results of the inversion of the first survey data set.

Claims28

Dependent claims

A computer-implemented method of analysing results from a controlled source electromagnetic survey of a region of interest, the region of interest containing a previously identified geological structure suitable for bearing hydrocarbons, the method comprising:

providing a first controlled source electromagnetic survey data set obtained outside and away from the region of interest for a range of source-receiver orientations and offsets;
providing a second controlled source electromagnetic survey data set obtained inside the region of interest for a range of source-receiver offsets;
performing in a processor of a computer a mathematical inversion of the first controlled source electromagnetic survey data set to provide a model of the subterranean strata outside and away from the region of interest;
and
processing the second controlled source electromagnetic survey data set to provide a model of the subterranean strata inside the region of interest, wherein the processing takes account of the model of the subterranean strata outside and away from the region of interest.

2 more elements

A computer-implemented method of planning a controlled source electromagnetic survey of a region of interest, the region of interest containing a previously identified geological structure suitable for bearing hydrocarbons, the method comprising:

creating a model of a region outside and away from the region of interest, including a rock formation and a body of water above it;
creating a model of the region of interest which corresponds to the model outside of and away from the region of interest, but further including a hydrocarbon reservoir;
performing a simulation of an electromagnetic survey outside and away from the region of interest to provide a first simulated controlled source electromagnetic survey data set for a range of source-receiver orientations and offsets;
performing a simulation of an electromagnetic survey inside the region of interest to provide a second simulated controlled source electromagnetic survey data set for a range of source-receiver offsets;
performing in a processor of a computer a mathematical inversion of the first simulated controlled source electromagnetic survey data set to provide a simulated recovered model of the subterranean strata outside and displaced away from the region of interest;
and
processing the second simulated controlled source electromagnetic survey data set to provide a simulated recovered model of the subterranean strata inside the region of interest, wherein processing the second simulated controlled source electromagnetic survey data set takes account of the simulated recovered model of the subterranean strata outside and away from the region of interest.

4 more elements

Dependencies are inferred from the claim text.

Electromagnetic surveying

Life of this patent

Electromagnetic surveying

Life of this patent

Abstract

Claims28