Collapse Challenges in High-Temperature Geothermal Wells

Monday, March 25, 2024 | 09:30AM – 11:00AM CT High-temperature geothermal wells (temperature above 250°C) result in specific load cases induced by the temperature or by the well design itself. Several high-temperature geothermal well failures have been observed and reported in the literature in different parts of the globe due to collapse loads. The consequences for the operator are very severe, as in most cases, the well needs to be abandoned, resulting in both a huge financial impact due to the loss of the well and an immediate and unpredictable drop in energy supply. The purpose of this webinar is to review and analyze the possible root causes of casing collapse based on well design approach and lessons learned from the literature and to propose possible technical solutions to mitigate and avoid casing collapse failures in high temperature geothermal wells. In most geothermal wells, casing design has historically been based on classical API standard or low standards pipe sizes in material grades such as K55 or L80 fitted with buttress or semi-premium connections. The usage of these grades provides limited resistance to collapse, which can, in some cases, be insufficient to sustain the collapse loads induced by the temperature or related to the well environment and life cycle. The paper mentioned in this webinar includes a literature review of casing failures and well design evaluations to understand and quantify the main load cases that can generate collapse, such as cementing phase or “annulus” fluid pocket expansion due to high temperature changes during well production. It also explores the possibility to use pipes with increased collapse performance to prevent this type of failure. The higher collapse performances are achieved thanks to a tighter control of the manufacturing processes and the key geometrical and mechanical parameters of the pipe such as wall thickness, ovality, eccentricity, yield strength and residual stress. The control and the consistency of these parameters are the key drivers to achieve these enhanced collapse performances. Pipe collapse resistance can be increased up to 50% without adding extra weight to the pipe string. A comprehensive range of High Collapse and Extreme Collapse grades have been developed to provide enhanced resistance compared to classical OCTG grades. High Collapse and Extreme Collapse grades have already been successfully used in oil and gas applications such as drilling through salt domes or to cope with annulus pressure buildup in some High Pressure and High Temperature and deep-water wells. A thorough well design in partnership with the OCTG pipe manufacturer and the use of High Collapse grades in High Temperature geothermal wells can be a solution to prevent casing collapse and therefore ensure well reliability, longer-lasting wells, and a steady energy supply. All content contained within this webinar is copyrighted by François Penven and its use and/or reproduction outside the portal requires express permission from François Penven. This webinar is FREE for SPE Members. Webinar recordings will be available on-demand within 1 business day of the webinar completion. For those who attended the live webinar, your certificate will be available in your “Learner Profile” within 1 business day of the webinar completion