Patent ID: 8831923

Claim:
A method for structural modeling formation stresses, comprising: selecting an interval of the formation having stress induced anisotropy within a borehole; computing model parameters m 1 and m 3 by linear regression of radial profiles of shear moduli C 44 and C 55 using a computer wherein the model parameters m 1 and m 3 are obtained using a model; computing and outputting a maximum horizontal stress σ H and minimum horizontal stress σ h using the computer wherein the maximum horizontal stress σ H and minimum horizontal stress σ h are determined from a series of equations: σ H - σ h + C 55 ∞ - C 44 ∞ A E - 1 , ⁢ σ h ≈ σ v - C 55 ∞ - C 66 ∞ A E - 1 , ⁢ A E = - A 2 + A 2 2 - 4 ⁢ A 1 ⁢ A 3 2 ⁢ A 1 , ⁢ where , ⁢ A 1 - 2 ⁢ ( - P w + σ v ) ⁢ ⁢ A 2 = - ( C 44 ∞ + C 55 ∞ - 2 ⁢ C 66 ∞ - m 1 - m 3 - 2 ⁢ P w + 2 ⁢ σ v ) , ⁢ A 3 = C 44 ∞ + C 55 ∞ - 2 ⁢ C 66 ∞ . ( 3 ) P W =(P mud −P p ) P mud represents mud pressure in the borehole, P p represents pore pressure in the borehole, σ v represents vertical stress of the formation, A E represents an acoustical parameter, C 44 ∞ represents a far field slow shear modulus defined as r/a=7, where r represents a distance to the center of the borehole, a represents a radius of the borehole C 55 ∞ represents a far field fast shear modulus defined as r/a=7, and C 66 ∞ represents a far field Stonely shear modulus.