The Dow Chemical Company

Wayne F Nelson

Derrel G Gurley

Paul A Weiss

Onazip J Fournier

Charles H McLaurin

A tool is disclosed for shifting the sleeve of a port collar in a well casing, to open and close the ports in the collar. The basic tool is made up of a housing having a double piston assembly mounted slideably in a transverse bore in the housing. The transverse bore is intersected by a lengthwise bore in the housing. Fluid is carried into the housing from a tubing string connected into the lengthwise bore. The double piston assembly has an outside face in contact with fluid in the well casing, and an inside face in contact with fluid inside the housing bore. In addition, the outside face has a larger surface area than the inside face. This differential in the piston surface area allows the piston assembly to be held in a 'retract' position by applying fluid pressure to the outside face. Alternatively, the piston assembly can be moved laterally to engage the port collar sleeve by applying fluid pressure to the inside face. Pulling the tubing string upwardly shifts the sleeve to a position which opens the collar ports. Setting weight on the tubing string moves the sleeve downwardly to close the collar ports.

Device and method for shifting a port collar sleeve

The cementing collar described herein is designed primarily for cementing operations in oil or gas wells. The basic assembly includes a collar, an outer sleeve slidable in the collar, and an inner sleeve slidable in the outer sleeve. The collar and outer sleeve each have cementing ports therein. When the assembly is being run into the well casing, the collar and both sleeves are secured by shear pins in a position such that the cementing ports are closed. To open the cementing ports a trip bomb is dropped into the casing to engage a seat inside the outer sleeve. This causes the pins to shear and permits the outer sleeve to move down to a position in which the sleeve ports line up with the collar port. After cementing has been completed, a plug is flowed down the casing to engage the inner sleeve. Fluid pressure is applied behind the plug to shear the pins a second time. This moves the outer sleeve further down to a position in which the cementing ports are again closed.

Cementing collar and method of operation

A tool is disclosed for controlling flow of treating fluid from a tubing string into an earth formation, in which the bottom hole pressure is less than the hydrostatic pressure of the fluid in the string. In another application, the tool is used in conjunction with a wash tool to wash sediment out of casing perforations and slotted liners. Before the downhole operation is commenced, a slidable piston in this tool closes off fluid outlet ports, to prevent the fluid from 'gravity flowing' out of the tubing string. The piston is held in the closed position by the co-action of an adjusting bolt and a compression spring. The fluid is released from the tubing string by applying sufficient fluid pressure against the piston to overcome the spring load and thus move the piston downwardly past the fluid outlet port.

Method and tool for controlling fluid flow from a tubing string into a

The tool of this invention is designed primarily for removing unconsolidated sand and other debris from the well casing perforations and adjacent earth formation in an oil or gas recovery operation. The basic tool includes an upper valve unit and lower valve unit, which are coupled together by a surge chamber. In a typical cleaning operation the tool is lowered into the well casing on a tubing string, which includes a by-pass and a retrievable packer. When the tool is at the desired position in the casing, the packer is set and the by-pass is closed. Fluid under pressure is pumped down the casing annulus to trip a mandrel in the lower valve and open a flapper disk. Bottom hole pressure causes fluid in the formation to fill the surge chamber and the sand and debris falls to the bottom of the hole. The packer is then unset and fluid pressure down the tubing string trips a piston in the upper valve and allows a stationary mandrel to open another flapper disk. The tubing string is then lowered to wash out the sand and debris in the hole by reverse circulation. After the formation has been cleaned the packer can be released and re-set to perform a further treatment, such as gravel packing, to achieve sand control.

Tool for removing fluids and loose material from an earth formation

The invention is an elongated valved device adapted to be coupled between a string of tubing and a well bore packer. An outer sleeve is coupled at one end to the tubing and has a movable hollow mandrel into the other end of the outer sleeve. Advancing or retracting of the mandrel is afforded by rotating the mandrel to engage grooves in the periphery of the mandrel with lugs at the end of the outer sleeve, then moving the mandrel axially with respect to the outer sleeve. An inner sleeve is locked in position within the outer sleeve and has a spring loaded flapper valve assembly at its end facing the end of the mandrel. Advancement of the mandrel forces its end (curved) through the valve assembly.

Tubing tester

The invention is a differential fill valve apparatus principally for use in treating earth wells, usually in connection with cementing a string of casing into the well bore. The apparatus, at or near the low end of the casing, has a pressure actuated slidable piston which rises as liquid is encountered in the well bore opening parts for admitting liquid into the casing until the pressure from liquid in the casing reaches a predetermined ratio with respect to the pressure in the well bore annulus. Means are provided for locking the piston in its closed position after the casing string is in place in the well, permitting the use of the apparatus as conventional cementing valve apparatus.

Growing community of inventors

Wichita Falls, TX, United States of America

Wayne F Nelson