Wellbore integrity factors for CO₂ storage in oil and gas producing areas in the Midwest United States

Abstract

The condition of legacy oil and gas wells is an important issue for geologic CO 2 storage projects. Many regions with large CO 2 point sources coincide with historical oil and gas fields. This is especially apparent in the Midwestern United States, where over one million oil and gas wells are present dating back to the late 1800s. To investigate wellbore integrity factors in this region, the condition of oil and gas wells in Michigan and Ohio was summarized based on well status, depth, construction, age, and plugging specifications. To better understand the impact of well integrity on a local scale, six test study areas were also analyzed. These hypothetical test study areas were based on subsurface area necessary for an industrial scale CO 2 storage application. Detailed records were used to categorize well conditions, and corrective actions necessary to repair the wells were then assigned. The results of the test study area analysis provide a real representation of the level of effort necessary to prepare sites for CO 2 storage. Actions may involve relatively low-effort tasks to examine wellheads or more extensive well re-entry and plugging. The analysis indicated that many areas may have hundreds of wells, but no wells penetrating the deeper CO 2 storage zones. At sites where many wells require corrective action, it may be challenging to efficiently plug and abandon wells. Options such as testing wellhead pressures, surface monitoring of CO 2 leakage, and less extensive plugging requirements may help offset costs associated with remediating a large number of wells. C

Evaluation of CO2 attack in wellbore class G cement: influence of epoxy resins, composites and minerals as additives

“…Such failures can lead to significant environmental impacts such as gas leakage into the atmosphere as well as water and soil contamination. 7,10,13 To predict potential CO 2 leakage from wellbores, it is crucial to understand transfer phenomena and chemical reactions between CO 2 and well materials. 8,14 Chemical reactions are the most common concerns related with wellbore integrity due to the instability of Portland cement in CO 2 -rich aqueous environments and many geochemical reactions that occur continuously during the cement degradation process such as cement components dissolution (e.g., calcium and silicon oxides), reaction products precipitation (calcium carbonates), and casing corrosion.…”