Composite Ceramic Centralizers--An Innovative Solution for Geothermal Well Construction in Highly Corrosive Environments: Case History

Abstract

Hot and highly corrosive environments encountered in geothermal- well construction are just some of the complications operators are facing regularly. The selection of super-duplex, stainless-steel casing for these demanding environments provides exceptional strength and corrosion resistance. This alloy has excellent resistance to chloride stress corrosion cracking, high thermal conductivity, and a low coefficient of thermal expansion. In addition, unusual slimhole-drilling applications and the need for versatile and robust casing attachments are essential to help ensure a successful primary cementing operation. The limited clearance in slimhole applications could cause problems while running casing, especially in rough boreholes. In these scenarios, proper standoff is required to achieve optimum cement distribution as well as to allow the option of circulation when running in the hole, and for proper hole cleanout. This paper presents a case history of the application of an innovative, composite-ceramic-centralizer technology that is mechanically formed and chemically bonded directly to the casing surface. This technology provides a reliable centralization option for close-tolerance wellbores, uninterrupted flow during circulation, extreme abrasion and impact resistance, and CO2 and H2S resistance. Enabling a homogeneous cementslurry distribution that prevents the casing from expanding or buckling when heated and helping prevent corrosion is critical for the life of a geothermal well.