Methods for facilitating the descent of well tools through deviated well bores

Claim 1

A method for lowering a well tool suspended within a well bore from a cable having a laterally-stiffened lower portion coupled to the well tool and an upper portion extending therefrom through the well bore and operatively spooled on a powered winch at the surface comprising the steps of: unreeling said cable from said winch to lower said well tool into the well bore; measuring a characteristic representative of the descent of said well tool through the well bore; and, whenever said well slows its descent, powering said winch to unreel additional lengths of said cable into the well bore for reducing tensile forces therein and developing compressive forces in said laterally-stiffened lower portion thereof to urge said well tool on further through the well bore.

Claim 2

A method for logging a well bore having a nonvertical interval therein comprising the steps of: dependently coupling a logging instrument to an electrical logging cable having at least a lower portion thereof resistant to lateral bending and an upper portion thereof operatively spooled onto a powered winch adapted to be selectively driven forwardly and reversely for respectively lowering and raising said logging instrument into and out of a well bore to be logged; unspooling said cable from said winch to lower said logging instrument into a well bore to be logged; whenever the descent of said logging instrument is halted, driving said winch forwardly for reducing tensile forces in said upper cable portion and developing compressive forces in said lower cable portion to move said logging instrument through nonvertical intervals of the well bore to greater depths therein; and, after said logging instrument has reached a selected well bore depth, driving said winch reversely to respool said cable back onto said winch for logging the well bore as said logging instrument is returned toward the surface.

Claim 3

A method for logging a well bore having a nonvertical interval therein comprising the steps of: dependently coupling a logging instrument to an electrical logging cable having a lower portion thereof resistant to lateral bending and an upper portion thereof operatively spooled onto a powered winch adapted to be selectively driven forwardly and reversely for respectively lowering and raising said logging instrument into and out of a well bore to be logged; unreeling said cable from said winch to lower said logging instrument into a well bore to be logged; whenever the descent of said logging instrument is slowed, driving said winch forwardly fOr reducing tensile forces in said upper cable portion and developing compressive forces in said lower cable portion to increase the speed of said logging instrument through nonvertical intervals of the well bore; and, after said logging instrument has reached a selected well bore depth, driving said winch reversely to reel said cable back onto said winch fore returning said logging instrument toward the surface.

Claim 4

A method for advancing well tool disposed within a downwardly-inclined well bore interval and suspended therein from a cable having a lower portion coupled to the well tool and an upper portion extending therefrom through the well bore to the surface comprising the steps of: moving said upper cable portion downwardly into the well bore to reduce tensile forces therein and develop downwardly-acting compressive forces in said lower cable portion for producing corresponding downwardly-acting forces on said well tool; measuring a characteristic indicative that said downwardly-acting forces are acting on said well tool; and, so long as said characteristic indicates that said downwardly-acting forces are acting on said well tool, moving additional lengths of said cable from the surface into the well bore to produce additional downwardly-acting forces on said well tool for advancing said well tool further downwardly through the downwardly-inclined well bore interval.

Claim 5

A method for logging a well bore comprising the steps of: dependently coupling a logging instrument to the lower portion of an electrical logging cable adapted to resist lateral bending and having an upper portion thereof operatively spooled onto a powered winch adapted to be selectively driven forwardly and reversely for respectively lowering and raising said logging instrument into and out of a well bore to be logged; unreeling said cable from said winch to lower said logging instrument into a well bore to be logged; observing at the surface signals produced by said logging instrument for obtaining indications that said logging instrument is descending into the well bore; whenever said signals indicate that the descent of s aid logging instrument is slowed, driving said winch forwardly for reducing tensile forces in said upper cable portion and developing corresponding downwardly-acting compressive forces in said lower cable portion to move said logging instrument further downwardly in the well bore; and, after said logging instrument has reached a selected well bore depth, driving said winch reversely to respool said cable back onto said winch for returning said logging instrument toward the surface. 7. A method for logging a well bore comprising the steps of: dependently coupling a logging instrument to an electrical logging cable adapted to withstand axial compressive forces without being bent double within the spatial limits of the well bore, said cable being operatively spooled onto a powered winch adapted to be selectively driven forwardly and reversely for respectively lowering and raising said logging instrument into and out of a well bore to be logged; unreeling said cable from said winch to lower said logging instrument into a well bore to be logged; observing at the surface logging signals produced by said logging instrument for obtaining indications that said logging instrument is descending into the well bore; whenever said logging signals indicate that the descent of said logging instrument is slowed, driving said winch forwardly for reducing tensile forces in said cable and developing corresponding compressive forces in the lower portion thereof to facilitate the descent of said logging instrument through the well bore; measuring a characteristic indicative that said compressive forces are acting on said logging instrument; and, so long as said characteristic indicates that said compressive forces are acting on said logging instrument said logging signals indicate that said logging instrument is descending into the well bore, continue driving said winch forwardly to carry saiD logging instrument to a selected well bore depth.

Claim 8

A method for logging a well bore having a nonvertical interval therein comprising the steps of: dependently coupling a logging instrument to an electrical logging cable adapted to resist lateral flexing under compressive loading and operatively spooled onto a powered winch adapted to be selectively driven forwardly and reversely for respectively lowering and raising said logging instrument into and out of a well bore to be logged; unreeling said cable from said winch to lower said logging instrument into a well bore to be logged; whenever the descent of said logging instrument is retarded, driving said winch forwardly for reducing tensile forces in said cable; and forcing the upper portion of said cable downwardly for developing corresponding compressive forces in the lower portion thereof to urge said logging instrument toward greater depths in said well bore.