Apparatus and method for positioning a tool in a deviated section of a borehole

Abstract

Apparatus and method for positioning a tool, such as a surveying instrument, in the deviated section of a borehole includes a flexible rod and a positioning assembly. The flexible rod extends from the vertical section into the deviated section of the borehole with the tool being connected to the downhole end of the rod. The positioning assembly is connected to the uphole end of the rod for positioning the downhole end of the rod in the deviated section of the borehole when the positioning assembly and the uphole end of the rod are in the vertical section of the borehole. In one embodiment, the positioning assembly is a biasing assembly, such as a weight, for urging the downhole end of the rod and tool into the deviated section. In another embodiment, the positioning assembly is an orienting assembly for rotationally orienting the rod and tool in the borehole as the rod is lowered into the borehole. The orienting assembly also provides for fixing the rotational orientation of the rod and tool with respect to a predetermined point on the circumference of the drillstring and limiting the downhole travel of the rod and tool as the rod is lowered into the drillstring.

Dependencies are inferred from the claim text.