Methods and systems for estimating stress using seismic data

A system comprising:

• 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,
• wherein the minimum horizontal stress is determined by a relation
• σ
• x
• =
• σ
• z
• ⁢
• v
• ⁡
• (
• 1
• +
• v
• )
• 1
• +
• EZ
• N
• -
• v
• 2
• between the vertical stress σhd z, Young's modulus E, Poisson's ratio ν, and normal compliance ZN.

A method for estimating principal stresses of a subterranean formation using a computer system comprising:

• determining, using the computer system, rock strength parameters from seismic data of the formation;
• calculating, using the computer system, anisotropic elastic properties of the formation using at least said determined rock strength parameters;
• and
• determining, using the computer system, 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,
• wherein the maximum horizontal stress is determined by a relation
• σ
• y
• =
• σ
• z
• ⁢
• v
• ⁡
• (
• 1
• +
• EZ
• N
• +
• v
• 1
• +
• EZ
• N
• -
• v
• 2
• )
• between the vertical stress σZ, Young's modulus E, Poisson's ratio ν, and normal compliance ZN.

A system comprising:

• 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,
• wherein the maximum horizontal stress is determined by a relation
• σ
• y
• =
• σ
• z
• ⁢
• v
• ⁡
• [
• 1
• +
• EZ
• N
• +
• v
• 1
• +
• EZ
• N
• -
• v
• 2
• ]
• between the vertical stress σz, Young's modulus E, Poisson's ratio ν, and normal compliance ZN.