Casing Connection Selection for Geothermal Applications Using New Input from HPHT and Thermal Wells Testing Protocols

Abstract

OCTG connection selection for Oil-Gas wells has evolved over the past 10 years switching from field proven technologies to fully qualified products. This change has been pushed by the O&G end users’ need for a more reliable and better sealing connections in challenging well conditions (HPHT) and thermal wells where plastic deformation occurs (SAGD – CSS). This paper contains a summary of the evolution of Premium Connections main design concepts; the applicable testing protocols used to validate premium connections performance within the elastic limit and in the plastic region due to thermal effect. Detail explanations of the characteristics of the testing methods currently in place, ISO 13679 and TWCCEP protocol, are included. The paper also contains additional study to correlate the geothermal casing needs in terms of thermal cycles/loads and newly available testing data to make designs more reliable. Finally, the paper concludes with recommendations on connection selection based on the existing testing data.