Patent ID: 8223586

Claim:
A method for analyzing in-situ stress of a formation interval, comprising: receiving a first log data and a second log data using an A/D card of a computer; computing the anisotropic shear moduli C 44 , C 55 and C 66 by using the first log data using the computer; determining in-situ stress type based on the anisotropic shear moduli C 44 , C 55 , and C 66 and selecting an in-situ stress expression corresponding to the in-situ stress type using the computer; computing Vertical stress σ v and Minimum horizontal stress σ h by using the second log data using the computer; computing stress regime factor Q of the formation interval based on the in-situ stress type using the computer; and computing and outputting the maximum stress σ H by using the stress regime factor Q, Vertical stress σ v , and Minimum horizontal stress σ h using the computer.