Patent ID: 9494704
Filing Date: 2016-11-15
CPC Classification: G01V

Claim Text:
1. A method for estimating maximum and minimum horizontal stresses in a formation in which a deviated borehole is present, the method comprising: determining radial profiles of Stoneley, fast dipole shear, and slow dipole shear slownesses using first orthogonal axes defined by an azimuth of the deviated borehole from a North direction and a deviation of a longitudinal axis of the deviated borehole from a vertical direction; calculating dipole shear moduli C44″ and C55″ defined in the first orthogonal axes using the fast dipole shear slowness and the slow dipole shear slowness; calculating modulus C66″ defined in the first orthogonal axes using the Stoneley slowness; estimating a set of stresses defined in the first orthogonal axes by performing an inversion that uses far-field shear moduli C44″, C55″, and C66″ and radial profiles of dipole shear moduli C44″ and C55″ at two or more different radial positions; and transforming the set of stresses defined in the first orthogonal axes to maximum and minimum horizontal stresses defined in second orthogonal axes that are aligned with the North direction and the vertical direction.