Induction logging sonde including a folded array apparatus having a plurality of receiver cowound coils and bucking coils

A logging sonde adapted to be disposed in a wellbore, comprising:

• an array section having an end, said array section including,
• a transmitter coil located at said end of said array section, and
• a plurality of cowound bucking coils and receiver coils located adjacent to one end of said transmitter coil within said array section, each of said plurality of cowound bucking coils and receiver coils including,
• a bobbin, and
• a receiver coil (N-1) and a bucking coil (N) cowound together about said bobbin, said bucking coil (N) being associated with another receiver coil (N),
• said bucking coil (N) being designed to balance a mutual coupling between the transmitter coil and said another receiver coil (N) and not between the transmitter coil and said receiver coil (N-1);
• and
• wherein said transmitter coil is not cowound.

A logging tool adapted to be disposed in a wellbore, comprising:

• a sensor array having an end;
• said sensor array including,
• a transmitter coil having an end and located adjacent to said end of said sensor array and adapted for inducing a current in a formation penetrated by the wellbore, and
• a cowound receiver coil and bucking coil located adjacent to said end of said transmitter coil, said cowound receiver coil and bucking coil including,
• a bobbin;
• a bucking coil (N) wound about said bobbin in one direction;
• and
• a receiver coil (N-1) wound about said bobbin in a direction opposite to said one direction,
• the receiver coil (N-1) adapted to conduct signals in response to said current in said formation, wherein said transmitter coil is not cowound.