Method of determining formation anisotropy in deviated wells using separation of induction mode
AssigneeBaker Hughes Incorporated
InventorsLeonty A. Tabarovsky, Mikhail Epov, Michael B. Rabinovich
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Abstract
Measurements are made with a multicomponent induction logging tool in earth formations in a borehole inclined to earth formations. A combination of principal component measurements is used to determine the horizontal resistivity of the earth formations. The determined horizontal resistivities are used in a model for inversion of other components of the data to obtain the vertical formations resistivities. When multifrequency measurements are available, frequency focusing is used.
Claims14
A method of lagging a subsurface formation comprising a plurality a layers each having a horizontal conductivity and a vertical conductivity, the method comprising:
- (a) conveying an electromagnetic logging tool into a borehole in the subsurface formation, said logging tool including a plurality of transmitters and a plurality of receivers, at least one of said transmitters and at least one of said receivers inclined to an axis of the tool, said borehole having an axis inclined at a nonzero angle to a normal to said layers;
- (b) using said electromagnetic logging tool for obtaining a plurality of measurements with a plurality of pairs of said transmitters and receivers;
- (c) using a first subset of said plurality of measurements for determining a horizontal conductivity associated with each of said layers;
- and
- (d) using determined horizontal conductivities and a second subset of said plurality of measurements for determining a vertical conductivity associated with each of said layers.
Dependencies are inferred from the claim text.