METHODS AND SYSTEMS FOR ESTIMATING STRESS USING SEISMIC DATA
First Claim
1. A method for estimating principal stresses of a subterranean formation comprising:
- determining rock strength parameters from seismic data of the formation;
calculating anisotropic elastic properties of the formation using at least said determined rock strength parameters; and
determining principal stresses of the formation using at least the calculated anisotropic elastic properties and the rock strength parameters of the formation, wherein the principal stresses comprise a vertical stress, a minimum horizontal stress, and a maximum horizontal stress.
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Abstract
A method for estimating principal stresses of a subterranean formation from seismic data. In one embodiment, rock strength parameters from seismic data of the formation is first determined to calculate the anisotropic elastic properties of the formation. The three principal stresses of the formation: vertical stress, minimum horizontal stress, and maximum horizontal stress, is determined using at least the calculated anisotropic elastic properties and the rock strength parameters of the formation. From the estimated principal stresses, the differential ratio of the maximum and minimum horizontal stresses can be determined to indicate optimal zones for hydraulic fracturing. In another embodiment, a tectonic strain term is introduced to calibrate the estimated principal estimated stress to a known reference point. In yet another embodiment, hoop stress is incorporated to estimate the fracture initiation pressures.
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Citations
16 Claims
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1. A method for estimating principal stresses of a subterranean formation comprising:
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determining rock strength parameters from seismic data of the formation; calculating anisotropic elastic properties of the formation using at least said determined rock strength parameters; and determining principal stresses of the formation using at least the calculated anisotropic elastic properties and the rock strength parameters of the formation, wherein the principal stresses comprise a vertical stress, a minimum horizontal stress, and a maximum horizontal stress. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system comprising:
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a first calculation logic that is operable to determine rock strength parameters from seismic data of a subterranean formation; a second calculation logic that is operable to calculate anisotropic elastic properties of the formation using at least said determined rock strength parameters; and a third calculation logic to determine principal stresses of the formation using at least the calculated anisotropic elastic properties and the rock strength parameters of the formation, wherein the principal stresses comprise a vertical stress, a minimum horizontal stress, and a maximum horizontal stress. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification