Induction dipmeter apparatus and method

Apparatus for determining the dip and/or dip azimuth of formations surrounding a borehole, comprising:

• first, second, and third transmitter coils having mutually orthogonal axes;
• means for individually energizing said transmitter coils;
• electronic transmitter steering means for controlling said energizing means to electronically steer the direction of the magnetic moment resulting from the magnetic field components generated by said transmitter coils;
• first, second, and third receiver coils having mutually orthogonal axes;
• and
• receiver processing means for processing the signals induced in said receiver coils.

A method for determining the dip and/or dip azimuth of a formation bedding plane surrounding a borehole, comprising the steps of:

• (a) transmitting electromagnetic energy into said formations from an electronically steerable transmitter within said borehole;
• (b) receiving, at an electronically steerable receiver within said borehole, induced electromagnetic signals;
• (c) rotating the receiver direction in a plane substantially perpendicular to the direction of said transmitter;
• (d) detecting the receiver output;
• (e) varying the transmitter direction as a function of the receiver output;
• and
• (f) repeating steps (c), (d), and (e) until the transmitter direction is substantially perpendicular to the formation bedding plane.

Apparatus for determining properties of subsurface formations surrounding a borehole, comprising:

• an array of transmitter coils;
• an array of receiver coils;
• means for individually energizing said transmitter coils;
• electronic transmitter steering means for controlling said energizing means to electronically steer, in three dimensions, the direction of the magnetic moment resulting from the magnetic field components generated by said transmitter coils;
• and
• receiver processing means for processing the signals induced in said receiver coils.

Apparatus for determining properties of subsurface formations surrounding a borehole, comprising:

• an array of transmitter coils;
• an array of receiver coils;
• means for individually energizing said transmitter coils;
• electronic transmitter steering means for controlling said energizing means to electronically steer the direction of the magnetic moment resulting from the magnetic field components generated by said transmitter coils;
• and
• receiver processing means for processing the signals induced in said receiver coils, said receiver processing means including electronic receiver steering means for electronically steering the direction of said receiver processing means in three dimensions.