First salt well plugged with PWC

Key facts
• Location: The Netherlands
• Well type: Salt well, onshore
• Rig Type: Hydraulic workover unit
• Key benefits: Well plugged in 5.5 days, no swarf cuttings brought to the surface
• Key capabilities: Proving that PWC® is effective for salt producing wells too

The customer’s challenge
The well in question had been drilled in 1995 as a brine producer. In August 2016, annular pressure increased due to a probable top-down cement leakage. In November 2016, pressure decreased again back to its original 33 bar, likely to have been caused by a top-down cement block cured by salt precipitation.

The operator needed to plug and abandon the well, and wanted to investigate an alternative method to section milling. As a result, they contracted HydraWell to use the PWC® method at a salt well for the first time.

The HydraWell solution
Although the well design at a salt well is quite similar to that of an oil and gas well, the biggest difference is that the work had to be done from a 20-metre tall hydraulic work-over unit, meaning less space and significantly higher number of connections. The job was conducted with the PWC® method, using a single-trip HydraHemeraTM system.

HydraWell first perforated the 50-metre interval with 7″ TCP guns from 2,115-2,165 metres in the well. ICF was then sat as a fundament for cement plug at 2,171 metres. Using the HydraHemeraTM tool, the annulus was washed and cleaned behind the perforations, and a place spacer was positioned in the entire cross section from base to above the top perforation. The cement plug was then placed across the perforated interval using the HydraHemeraTM cementing valve and HydraArchimedesTM cementing insurance tool to jet and force cement through the perforations into the 10-3/4″ x 13-3/8″ annulus. Excess cement was then circulated out at 2,000 metres, before the plug was tagged and pressure tested to verify the in-well barrier.

The result
The salt producing well was safely plugged and abandoned in 5.5 days. Given that this was the first time the PWC® method was utilised to plug a salt well, HydraWell took a very conservative approach to execution speed, for example without the use of night shifts. Trip time was longer than normal due to the use of a hydraulic work-over unit, but the entire job was executed safely and effectively. No swarf cuttings had to be brought to the surface, reducing the customer’s recycling costs.

For more information about this type of job, please contact:
Eivind A. Knudsen, sales & operations engineer, tel: +47 41 63 13 42, email: eak@hydrawell.no

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