地熱・CCUS用途におけるケーシング設計の進化：デジタル・自動化ワークフロー時代における従来の包絡線を超えて

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🔬研究者:坑井工学とデジタルデータ基盤（OSDU）の統合が、長期炭素貯留・地熱の信頼性評価にどう効くかを示す枠組みとして参照できる。

🏢実務担当者:CCS・地熱プロジェクトの設計・調達担当は、環状圧管理と自動化ワークフローを長期健全性・監査対応の観点で設計要件に組み込む判断材料にできる。

🏛政策担当者:CCS規制（Class VI相当）の枠組みが既存API基準で捉えきれない設計課題を認識し、坑井健全性要件の整備に反映すべき点を示す。

Casing design has historically evolved in response to increasingly complex well environments, advances in modelling capability, and lessons learned from field failures. This paper examines the next phase of that evolution, where Geothermal and Carbon Capture, Utilisation and Storage (CCUS) applications introduce load scenarios, regulatory requirements, and integrity challenges beyond the scope of conventional oil and gas practice. In parallel, the industry is undergoing a broader transition toward digitalisation and automation of design workflows, impacting existing casing design practices. The objective of this paper is to assess how geothermal conditions, CO2 containment requirements, and the increasing adoption of automated methodologies for annular pressure variation and management in challenging wells, including subsea developments, together with Open Subsurface Data Universe (OSDU)-based data integration, are reshaping casing design methodology and challenging established approaches. The paper reviews emerging casing design challenges across geothermal and CCUS applications and evaluates their compatibility with traditional design frameworks. For hot and superhot geothermal wells, the analysis focuses on environments where plastic deformation, post-yield tubular behaviour, thermal cycling, connection fatigue, and time-dependent material effects become significant. For CCUS wells, the study considers API and Class VI regulatory requirements, together with subsea operating conditions, including trapped annuli, annular pressure reduction, and potential annular vacuum conditions associated with cold CO2 injection. In parallel, the role of automated design workflows to address modern well architectures is assessed, particularly for subsea developments where annular pressure behaviour has long been a critical design driver. These workflows include annular pressure variation (APV) and annular pressure envelope (APE) methodologies and are evaluated as part of a broader shift towards scalable, repeatable, and auditable casing design processes, supported by OSDU-based data integration and data sharing. The analysis indicates that some next-generation wells introduce conditions that extend beyond the assumptions of conventional elastic, deterministic casing design approaches. Superhot geothermal wells may require intentional design into the post-yield regime, while CCUS wells introduce long-term integrity requirements, complex thermodynamic behaviour, and annular pressure responses not fully captured by traditional load cases. At the same time, automated annular pressure methodologies enable more systematic evaluation of multi-scenario loading conditions across a wide range of well types, extending beyond CCUS-specific applications. Existing API standards and regulatory frameworks, including Class VI, provide an essential foundation but do not fully address all of the emerging design considerations associated with these applications. Digital workflows and integrated data platforms improve the ability to manage complexity but introduce new challenges related to model transparency and preservation of engineering judgement. This paper positions geothermal and CCUS applications as part of the next stage in the evolution of casing design, while also identifying automation and digital integration as independent drivers of change across the industry. It integrates post-yield geothermal design, CCUS annular behaviour including pressure reduction and vacuum conditions, regulatory considerations, and automated annular pressure methodologies within a unified framework. The work highlights a transition toward system-level, lifecycle-based casing design, supported by digital data environments such as OSDU, providing a forward-looking perspective on well integrity in increasingly complex and long-duration operating conditions.

• semanticscholar https://doi.org/10.2118/236451-msfirst seen 2026-11-05 05:58:47 · last seen 2026-11-06 05:30:53