Patent Number: 7,712,530

Title: Pre-stressed annular sealant and method of creating a durable seal in a well bore annulus

Abstract: A pre-stressed annular sealant and method of creating a durable seal in a well bore annulus which is based on hydraulic cement that is designed to be easily pumped and placed into a casing-wellbore annulus, to set into a hardened mass, and to then undergo post-set crystal growth and phase changes in the crystalline matrix to combat inherent volumetric shrinkage and to create internally-generated compressive stress in the cement matrix. This internally-generated compressive pre-stressing compensates for tensile stress induced by well operations. The tensile stress must be greater in magnitude than the magnitude of the compressive pre-stress plus the magnitude of the cement's tensile strength before the cement sheath will fail in tension. This expansion and pre-stressing also creates significantly higher shear bond strengths than those developed with ordinary hydraulic cement.

Inventors: Edgley; Kevin (Duncan, OK), Watters; Larry (Spring, TX), Sabins; Fred (Montgomery, TX), Sonnier; Paul (Kingwood, TX)

Assignee: Superior Energy Services, L.L.C.

International Classification: E21B 33/13 (20060101); C04B 9/12 (20060101)

Expiration Date: 5/11/12018