Patent ID: 6834726
Filing Date: 2004-12-28
Classification: E21B

Abstract:
A method or reducing fluid surge in a tubular string, comprising:running the string into a wellbore the string having a surge reduction apparatus, the apparatus including: a body having a bore therethrough, the bore providing a fluid path from a lower end to an upper end of the body; at least one fluid bypass path permitting the wellbore fluid to pass from the lower end of the body to an annular area formed between an outer surface of the body and the walls of a wellbore therearound; and whereby the at least one fluid bypass path is selectively and redundantly closable to the flow of fluid; permitting the wellbore fluid that enters the lower end of the body during running of the string to flow through the at least one fluid bypass path; and closing the at least one fluid bypass path, whereby redundant closing includes the use of a breakable piston sleeve and at least one member of the group consisting of rupturing a disc at hydrostatic pressure and breaking a breakable plug.