Dipmeter displacement qualifying technique

A method of mapping the attitudes of earth formation features in the vicinity of a borehole comprising the steps of:

• (a) passing a tool having at least four transducers through a borehole to obtain a respective depthvarying signal from each transducer, each of said transducers being urged in the direction of the borehole wall to achieve satisfactory transducer-wall contact;
• (b) detecting which, if any, of the transducers fail to achieve satisfactory transducer-wall contact;
• and
• (c) combining at least three of said depth-varying signals, less the signal from any transducer failing to achieve said satisfactory transducer-wall contact, to generate a tangible representation of the attitudes of said earth formation features.

A method of mapping the attitudes of earth formation features in the vicinity of a borehole comprising the steps of:

• (a) passing a group of at least four transducers through a borehole to obtain a respective depth-varying signal from each transducer, each of said transducers being urged toward a selected position relative to the borehole;
• (b) detecting which, if any, of the transducers fail to achieve their respective selected positions relative to the borehole;
• and
• (c) combining the depth-varying signals, less the signal from any transducer failing to achieve its respective selected position relative to the borehole, to generate tangible representations of the attitudes of said earth formation features.

A method of mapping the attitudes of earth formation features in the vicinity of a borehole comprising the steps of:

• (a) passing a group of at least four transducers through a borehole to obtain a respective depth-varying signal from each transducer, each of said transducers being urged toward a selected position relative to the borehole, and combining respective pairs of said depthvarying signals to find probable displacements therebetween corresponding to a probable match of signal features thereof;
• (b) filtering the probable displacements to retain as the most valid ones those which indicate that the transducers from which the depth-varying signals resulting in the displacements were obtained were substantially in contact with the borehole wall;
• and
• (c) producing, from the displacements selected as the most valid ones through said filtering, tangible representations of the attitudes of earth formation features in the vicinity of the borehole.

A system comprising:

• (a) means for obtaining a respective depthvarying signal from each of at least four transducers passed through a borehole in an earth formation while urging each transducer toward a selected position relative to the borehole;
• and
• (b) means for detecting which, if any, of the transducers failed to achieve their respective selected positions relative to the borehole while passing therethrough, and for combining the depth-varying signals,
• less the signal from any transducer failing to achieve its respective selected position relative to the borehole, to generate tangible representations of the attitudes of earth formation features in the vicinity of the borehole.