Abstract: Method and apparatus for cementing a casing in a borehole in two distinct stages by connecting the tool of the invention in series relationship respective to the casing and running the entire tool string downhole into the borehole. The tool which connects the upper and lower casing strings together includes a coupling member actuated by relative movement between the upper and lower strings. The tool always captures the upper and lower casing strings to one another and when the tool is unlatched and the upper casing string lifted, a lateral flow passageway is opened which enables cement to be pumped downhole to the tool and laterally directly into the borehole annulus.

Abstract: Apparatus for completing a wellbore which has a hydrocarbon containing formation located downhole therein and wherein the well is perforated and filled with mud. A special plug, made in accordance with the invention, is placed in the end of a tubing string, and the string run dry into the borehole with the lower end of the string terminating in proximity of the perforations. The annulus is packed off and a weight dropped down through the string. The weight impacts against a special valve contained within the plug, thereby upsetting a valve element. This action communicates the interior of the string with the borehole, whereupon the lower borehole or bottomhole pressure is equalized across the plug, and the plug and weight fall from the end of the string and to the bottom of the borehole. The string is opened to ambient which allows flow to occur in order to clean out the well, and thereafter the string is connected to a gathering system.

Abstract: A cementing staging tool for use downhole in a borehole which is interposed in a casing string and manipulated by longitudinal and rotational movement of the upper casing string. The tool enables cement to be pumped down through the string of casing to form a lower plug. The upper casing string is then rotated and thereafter lowered to thereby open a lateral flow passageway through which cement can be pumped. The cement flows through the tool and fills the borehole annulus, thereby cementing the casing string to the borehole wall. The tool is closed by lowering the upper marginal length of the casing string.The tool maintains the ends of the casing string in captured relationship respective to one another at all times, and is left downhole as a permanent part of the casing string after the cementing operation has been completed.