Paper: Wellhead Isolation Improves Safety and Protects Equipment

Wellhead isolation tools can help operators control the high pressures often associated with well stimulation techniques. Fracturing requires the use of very corrosive and abrasive fluids under high pressure which can result in wellhead and tubing erosion. For safe well operation and other safety reasons, operators were usually forced to either change wellhead equipment for a fracturing job or to limit fracturing job design to the capabilities of their wellhead equipment. A wellhead isolation tool provides a means of isolating wellhead equipment from the high pressures and harmful fluids used in fracturing. This paper reviews the different wellhead isolation tools available and the advantages and disadvantages of each design. Suggestions to help ensure good fracturing job design are presented, and fluid flow through a wellhead isolation tool is reviewed and discussed. A discussion of the effects of fluid type on the wellhead isolation tool and tubing follows, and finally, some case histories help illustrate the use of this tool.