Standard logging tools have only one z-oriented transmitter coil and one z-oriented receiver coil, allowing only vertical-vertical transmitter-receiver configurations (that we write as "Z-Z"). This configuration minimizes problems with a borehole response, tool misalignment, and interpretation. Unfortunately, many formation features give little or no response to such a configuration - for example, anisotropy is not resolvable using the conventional array. A feasible solution to this difficulty is to develop "triaxial" tools, which generate or measure fields, which are not traditional and constitute a major advance in the industry, but there is a great deal that needs to be learned about the data quality control and interpretation. These logging tools are equipped with x-y-z oriented coils that have the ability of measuring magnetic field using different transmitter-receiver configurations, and these are: "Z-Z", "Z-H", and "H-H" (H, meaning horizontal in x or y directions).

Numerical experiments demonstrate that horizontal sources give fields, which are exquisitely sensitive to near borehole effects. This means that eccentering and tool flexure can lead to significant data noise. Array focusing is one means of correcting for these effects provided that the prior information concerning the borehole environment is available.

Vertical sources with horizontal field measurements are a modality, which has been used. This arrangement does minimize the effects of a borehole, and thus it can be numerically modeled without including the computationally expensive borehole.

Using "Z-H" transmitter-receiver configurations can gives us some information about non-axial symmetry responses, but what this really means?.

Different scenarios can gives similar non-axial symmetry responses and we look into some of them.

The use of horizontal transmitters or receivers, rise the question of how accurately we need to have the transmitter-receiver orientations in the field to be able to account for repeatability of the measurements. We also look into this problem. We started to develop a modeling effort as the only way to use data obtained form horizontal transmitters or receivers in an induction-logging tool.

Unfortunately, retaining the vertical source only leaves many formations unresolved. For example, uniaxial anisotropies are unresolved. Also, flexure of a long tool will introduce horizontal source components, whose horizontal field response can be large. Also geometric effects can be particularly pronounced in cross-well surveys.

A large amount of information in the data suggests a large number of interpretation parameters and a great deal of work in computing the response of even simple models. There are situations when the investment in interpretational infrastructure is just not cost-effective and conventional logs provide perfectly

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