Published on 26 April 2022
Three patches repair casing corrosion over cement squeeze in a shale gas producer well, featuring the longest patch without connections (155ft) installed ever worldwide.
Oilfield well tubular must cope with corrosive liquids and salted water. Metal oxidation can appear within six months due to casing exposure to corrosive fluids. If not treated, a corroded casing or tubing might be a real danger to the environment. Casing corrosion causes leaks and migrations into the formation that present severe risks of groundwater contamination. It also means drastic drops in production.
High losses or tight injectivity can jeopardize the quality of cement squeeze jobs. In numerous cases, remedial cementing operations are insufficient to guarantee reliable and sustainable
restoration of the casing integrity.
The patch would restore integrity inside the casing for the bottom section of the well where the corrosive fluids were produced, to repair corrosion without cement in the shallower depth. In this case, the client capitalized on Saltel expandable steel patch versatility to work in synergy with previous remedial cementing operations. This combination would thus restore integrity inside and outside the casing, ensuring a reliable well casing repair.
Schlumberger deployed the longest patch without connection ever installed.
The patch, 5.5in slimline, 155ft-long [47m], covered up to three corroded casing joints. The
previous record was a 118ft-long [36m] patch in the Democratic Republic of Congo.