Application of orthogonal dipole shear wave in the research of formation stress

Abstract

In the formation stress research, the formation may be regarded as the transversely isotropic medium. The main research is horizontal direction two stresses, namely maximum and minimum stress. The orthogonal dipole shear wave logging was gained, which made it convenient to calculate the stress. This article quotes the elastic modulus and the stress relations, which derived the transversely isotropic formation stresses formula. The formation fracture pressure and the borehole stability expression were gained based on the fracture pressure elementary theory. At the same time it has also calculated many parameters such as the elastic modulus, anisotropy coefficient and so on. The orthogonal dipole shear wave logging was analyzed, which indicated that there is no need to consider formation tectonic factor. When calculating maximum and minimum stress was same based on fast and slow shear wave velocity was same, which reflected the formation assumed the isotropic. When they have the difference, it is showed that the formation assumes the anisotropy. Commonly-used the isotropic medium is one kind of the transversely isotropic medium.