Patent 7168495 was granted and assigned to Oil States Energy Services L.L.C. on January, 2007 by the United States Patent and Trademark Office.
A casing-engaging wellhead isolation and method of the tool protects wellheads from lifting pressures induced by high fluid pressures and high flow rates used to stimulate low pressure wells. A releasable packer assembly mounted to a bottom end of a mandrel of the tool grips the casing and transfers the lifting pressures directly to the casing. Well treatment safety is thereby significantly enhanced.