Processing of multi-component induction data in the presence of borehole abnormalities

摘要

Measurements made by a multi-component induction logging tool may be corrected for tool eccentricity or the presence of a fracture in the earth formation. The corrected measurements may then be used in conjunction with a multi-array measurement to determine horizontal and vertical formation resistivity.

主权项

1. A method of evaluating an earth formation, the method comprising:
making a plurality of multi-component measurements using a logging tool in a borehole in the earth formation, the multi-component measurements indicative of a resistivity property of the earth formation, the multi-component measurements being affected by a disturbance in the azimuthal direction caused by an eccentering of the logging tool; estimating from the plurality of the multi-component measurements at least one principal component in a plane transverse to a longitudinal axis of the logging tool that is substantially unaffected by the disturbance, wherein estimating the at least one principal component further comprises performing a rotation of coordinates; and using the at least one principal component and a single frequency additional measurement indicative of a horizontal resistivity for estimating a horizontal resistivity (Rh) and a vertical resistivity (Rv).