Laboratory and Field Validation of a Sealant System for Critical Plug and Abandon Situations

Review of integrity of existing wells in relation to CO2 geological storage: What do we know?

“…In addition to mud conditioning, casing centralization is regarded as an important preparation for a cement job. Chemical washes/spacers are often pumped ahead of the cement slurry and act as a buffer between the mud and cement slurry, helping to thin and remove the mud (Nelson and Guillot, 2006). It is preferred for spacer and cement slurry to be in turbulent flow, if possible, to enhance mud removal and to minimize fluid channeling.…”

“…Thermal casing expansion causes a longitudinal shearing stress at the cement/casing interface or radial fracturing in the cement sheath. The failure mechanism is more complex owing to heat diffusion and differences in thermal properties between cement and casing steel (Nelson and Guillot, 2006). The complexity also lies in the fact that the thermally-induced expansion is cubical, so stress cracks induced in the cement are tensional rather than compressional (Goodwin and Crook, 1992).…”

“…Following drilling, all wells are completed by running a steel casing pipe in the borehole and cementing the casing in place by circulating a cement slurry down the casing and up the annular space between the casing and the surrounding rock (Nelson and Guillot, 2006). This cement should shield the steel casing from contact with subsurface fluids and should prevent these fluids from migrating vertically through the wellbore annular space to reach other zones.…”

“…These tests emphasize the important effects of mechanical defects on well integrity. Nagelhout et al (2005) tested the sealing ability of two different cement systems for use in plug-and-abandon operations. The flow of gas was measured across the cement plug at various differential pressures.…”

Posicionamento De Tampões Em Poços De Petróleo: Uma Investigação De Escoamentos De Inversão Por Gravidade

“…Afirmam que o uso de pastas de cimento flexíveis e expansíveis têm apresentado bons resultados no isolamento do poço. Nagelhout et al (132) 2 Força gel ou gel strength é a tensão de cisalhamento medida a baixas taxas de cisalhamento após o fluido repousar por um determinado período de tempo (procedimento API recomenda 10 s e 10 min). Esta é uma análise amplamente empregada pela indústria do petróleo para avaliar efeitos de tixotropia.…”