Slick line casing and tubing joint locator apparatus and associated

Abstract

A detector structure is used to sense and log the joints in a downhole jointed tubular structure, such as a well bore casing or production tubing, in a subterranean well. The detector is moved through the jointed tubular structure on an elongated positioning member, representatively a slick line, through a series of joints to be logged. As the detector passes through each joint it electromagnetically senses the joint and responsively generates an electric output signal. The output signal is used to momentarily cause a drag structure portion of the detector, in cooperation with the interior side surface of the tubular structure, to momentarily create a detectable tension change in the elongated positioning member. Alternatively, a pyrotechnic or compressed gas device may be used to create the detectable changes in response to the generation of the electrical output signals. These tension changes, which may be either tension increases or tension decreases, serve as mechanical output signals transmitted upwardly through the positioning member, and may be plotted on a strip chart recorder at the surface to record the joint locations and correlate them to the lowered depth odometer readings of the detection system. Using this joint detection apparatus, correlative joint logging procedures may be carried out for tool setting purposes without the necessity of utilizing an electrical conductor line.