地質学的炭素回収貯留（CCS）坑井におけるセメント劣化と完全性喪失
Cement Degradation and Integrity Loss in Geological Carbon Capture and Storage (CCS) Wells (原題)
Mohamed Fayez. Elnagar, Structural Consultant & Certified Forensic Engineering Expert MSc, PMP, MCIArb, MASCE, MACI, M.AISC, M.ASTM, M.FIDIC, PhD
🤖 gxceed AI 要約
日本語
本論文は、CCS坑井のセメントシースが超臨界CO2と塩水の反応で生じる炭酸環境により化学的に劣化し、さらに注入に伴う圧力・温度サイクルで機械的損傷が生じる複合メカニズムを整理する。炭酸化から溶脱への移行、C-S-H相の分解、セメント-鋼管・岩盤界面の剥離が漏洩経路を形成する。既存の設計基準では千年単位の貯留期間を予測できず、規制・環境リスクが未解決だと指摘する。
English
This paper reviews the coupled thermo-hydro-chemical degradation of wellbore cement in geological CCS, where carbonic acid attacks Portlandite and C-S-H phases, transitioning from carbonation to leaching and forming porous silica gel. Cyclic pressure and thermal loads from CO2 injection also cause debonding at cement-casing and cement-rock interfaces, creating leakage pathways. Existing standards lack predictive models for thousand-year storage integrity, leaving regulatory and environmental risks unresolved.
Unofficial AI-generated summary based on the public title and abstract. Not an official translation.
📝 gxceed 編集解説 — Why this matters
日本のGX文脈において
日本はCCSをGX推進の重要技術と位置づけ、北海道・苫小牧などで実証が進む。本論文は長期貯留のモニタリングや坑井閉鎖基準の整備に資する知見を提供し、国内CCS規制や事業リスク評価に示唆を与える。
In the global GX context
Globally, CCS is central to net-zero pathways and transition finance, yet long-term well integrity remains a key risk for carbon credit integrity and regulatory approval. This paper highlights the need for predictive degradation models to support MRV frameworks and ISSB-aligned climate risk disclosure for CCS projects.
👥 読者別の含意
🔬研究者:CCS坑井の長期完全性評価における化学-力学連成モデルの必要性と未解決課題を理解できる。
🏢実務担当者:CCS事業者は坑井設計・モニタリング・閉鎖計画においてセメント劣化リスクを考慮する必要がある。
🏛政策担当者:千年単位の貯留を想定した規制・基準策定において、予測モデルと長期モニタリング義務の重要性を示唆。
📄 Abstract（原文）
Geological Carbon Capture and Storage (CCS) represents a vital environmental engineering strategy to mitigate global greenhouse gas emissions by injecting supercritical carbon dioxide (sCO2) deep into depleted oil reservoirs or saline aquifers. However, this long-term carbon isolation strategy introduces a severe structural and chemical dilemma regarding the structural integrity of the cementitious barriers used to seal the injection wellbores. The core engineering dilemma is the continuous chemical degradation of the wellbore cement sheath when exposed to a highly aggressive, carbonic acid environment formed by the interaction of injected CO2 and native brine solution under extreme downhole pressures and temperatures. Mechanistically, the carbonic acid reacts with the calcium hydroxide (Portlandite) and calcium-silicate-hydrate (C-S-H) phases within the hardened cement paste. This carbonation process initially increases density but subsequently transitions into an aggressive leaching phase, dissolving the calcium carbonate and converting the structural cement matrix into a highly porous, mechanically weak silica gel. Concurrently, the cyclic pressure and thermal variations from the CO2 injection process induce alternating mechanical expansions and contractions of the steel casing, generating high tensile and shear stresses that cause debonding at the cement-casing and cement-rock interfaces. This chemical dissolution combined with mechanical micro-annulus formation creates preferential leakage pathways for the trapped gas to escape back to the surface. Traditional concrete and oilfield cement design standards fail to provide predictive models for this coupled thermo-hydro-chemical degradation over the mandated thousand-year storage horizon, creating an unresolved regulatory and environmental risk.
🔗 Provenance — このレコードを発見したソース
- openalex https://doi.org/10.5281/zenodo.23032909first seen 2026-10-01 04:54:58 · last seen 2026-10-01 04:55:06
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