Title

Designing wellbore plugging and abandonment materials based on nature's hydraulic barrier materials: A solution to prevent hydrocarbon leakage over time

Document Type

Conference Proceeding

Publication Date

1-1-2020

Abstract

In the oil and gas industry, drilling and completions of wellbores have undergone major technological improvements, that ultimately enabled safer exploration and production of fossil fuels. However, the plugging and abandonment (P&A) of wellbores had not attracted the same level of technological advancements. Wellbore plugging in offshore environments is challenging as the consequence of potential hydrocarbon leakage can cause cumulative damage to the fragile ecosystems for a long time before detection. Gas leakages are especially hard to detect and evaluate for appropriate wellbore intervention and mitigation. Preventing wellbore leakage requires a robust sealing material capable of reducing the permeability through wellbore infrastructure and surrounding formation to zero. One proposed way is to use zeolites as additives. Zeolites could act as scaffoldings for cement hydration reactions to take place and since they have crystal and pore structures similar to Calcium Silicate Hydrate (CSH), they have compatibility. This could act as a bridge between the natural formation and cement. Due to the non-hydraulic nature of zeolites, they could retain some pore water which could be released in an event of fracture providing water for secondary hydration of cement resulting in self-healing properties. Also, zeolites show a very strong skeletal structure despite their large reactive areas and pore sites. Hence, one of the ideas to be explored in this paper is to gain a deep understanding of the zeolite properties before adding it to cement in order to create an ideal hydraulic barrier material. By doing so, ultimately the aim is to achieve a barrier material which could mimic shale which is a natural cap rock and find application in wellbore plugging operation. This paper is focused on evaluation of a natural zeolite ferrierite, primarily microstructural characterization and its chemical stability in contact with fluids that resemble potential subsurface formation fluids. The data suggests that there is no major microstructural change in contact with: low pH aqueous solution, high salinity brine, synthetic oil and water, and some change in contact with high pH Calcium Hydroxide (Ca(OH) ) solution, after 7days exposure at 95°C. 2

Publication Source (Journal or Book title)

Society of Petroleum Engineers - SPE International Conference and Exhibition on Health, Safety, Environment, and Sustainability 2020, HSE and Sustainability 2020

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