Fault removal in geological models
First Claim
1. A computer-implemented method for fault removal of a plurality faults in a subsurface geological model to populate the model with desired information, comprising:
- (a) ordering the plurality of faults in reverse chronological order, and selecting a fault of the plurality of faults based on the reverse chronological order;
(b) removing the selected fault by iteratively solving, using a computer, an optimal control problem wherein Laplace'"'"'s equation is solved for an optimal set of rigid body transformations and boundary displacement vectors on the fault'"'"'s surface;
(c) repeating (b) as necessary to remove any remaining faults in the plurality of faults, one at a time, in reverse chronological order, resulting in a transformation of the geological model from faulted space to continuous space;
(d) populating said geological model with faults removed with selected grids or surfaces or physical property values;
(e) computing a mapping of the populated geological model back to the faulted space;
(f) storing the mapping and the populated geological model in the memory of the computer; and
(g) causing a well to be drilled based on the mapping for the production of hydrocarbons.
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Abstract
Method for transforming a discontinuous, faulted subsurface reservoir into a continuous, fault-free space where a complete geological model based on selected geological concepts can be built and updated efficiently. Faults are removed in reverse chronological order (62) to generate a pseudo-physical continuous layered model, which is populated with information according to the selected geological concept (68). The fault removal is posed as an optimal control problem where unknown rigid body transformations and relative displacements on fault surfaces are found such that deformation of the bounding horizons and within the volume near the fault surface are minimized (63). A boundary-element-method discretization in an infinite domain is used, with boundary data imposed only on fault surfaces. The data populated model may then be mapped back to the original faulted domain such that a one-to-one mapping between continuous and faulted spaces may be found to a desired tolerance (72).
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Citations
13 Claims
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1. A computer-implemented method for fault removal of a plurality faults in a subsurface geological model to populate the model with desired information, comprising:
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(a) ordering the plurality of faults in reverse chronological order, and selecting a fault of the plurality of faults based on the reverse chronological order; (b) removing the selected fault by iteratively solving, using a computer, an optimal control problem wherein Laplace'"'"'s equation is solved for an optimal set of rigid body transformations and boundary displacement vectors on the fault'"'"'s surface; (c) repeating (b) as necessary to remove any remaining faults in the plurality of faults, one at a time, in reverse chronological order, resulting in a transformation of the geological model from faulted space to continuous space; (d) populating said geological model with faults removed with selected grids or surfaces or physical property values; (e) computing a mapping of the populated geological model back to the faulted space; (f) storing the mapping and the populated geological model in the memory of the computer; and (g) causing a well to be drilled based on the mapping for the production of hydrocarbons. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13)
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10. A method for producing hydrocarbons from a subsurface region, comprising:
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obtaining a seismic survey of the subsurface region; using processed and interpreted data from the seismic survey to develop a geological model of the subsurface region, said geological model containing one or more faults; using a method to populate the model with geophysical information, wherein the method comprises; (a) ordering the plurality of faults in reverse chronological order, and selecting a fault of the plurality of faults based on the reverse chronological order; (b) removing the selected fault by iteratively solving, using a computer, an optimal control problem wherein Laplace'"'"'s equation is solved for an optimal set of rigid body transformations and boundary displacement vectors on the fault'"'"'s surface; (c) repeating (b) as necessary to remove any remaining faults in the plurality of faults, one at a time, in reverse chronological order, resulting in a transformation of the geological model from faulted space to continuous space; (d) populating said geological model with faults removed with selected grids or surfaces or physical property values; (e) computing a mapping of the populated geological model back to the faulted space; and (f) storing the mapping and the populated geological model in the memory of the computer; using the populated model in planning production of hydrocarbons from the subsurface region; and producing hydrocarbons from the subsurface region in accordance with the plan.
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Specification