Mechanical Scale Removal Saves USD 250,000 | Schlumberger
Case Study
Location
Middle East, Asia
Details

Al Khafji Joint Operations (KJO) efficiently broke hard calcite scale using the Torque-Action Debris Breaker wellbore cleanup and debris removal tool to save USD 250,000 in well intervention costs.

Products Used

Mechanical Scale Removal Saves USD 250,000

Using Torque-Action Debris Breaker tool instead of coiled tubing operation significantly reduces well intervention time

KJO's challenge: restore full wellbore accessibility

KJO encountered obstructions in 3.5-in tubing at 2,100 ft, 3,050 ft, and 3,500 ft during routine pressure and temperature surveys. The operation required an efficient mechanical tool to clean out extensive accumulated scale bridging a vertical production string and restore full wellbore accessibility. The well was previously shut down from operations for five years.

What was considered

The operator considered using a coiled tubing unit or workover rig to clear the scale and debris but sought a more cost-effective solution.

Schlumberger solution: break up sand and scale

The Torque-Action Debris Breaker tool from Peak Well Services with 1.9-in to 2.5-in subs breaks up concretions of sand and scale.

Image of Torque-Action Debris Breaker and close-up image of removed debris.
Post-op testing of the removed debris indicated it was calcite.
Image of Torque-Action Debris Breaker and close-up image of removed debris.
Image of the microscopic analysis of the scale.
Microscopic analysis of the scale determined to be calcite.
Image of the microscopic analysis of the scale.

What KJO achieved: reduce inventory and descaling time

KJO deployed a Torque-Action Debris Breaker tool on slickline to jar down in the well and apply a short-duration torque via the helically split torque sub. The tool enabled the team to clear the scale accumulations until 3,652 ft. The operator confirmed integrity of the tubing at the end of the slickline operation, allowing the slickline team to enter and run a memory pressure temperature survey to check the well deliverability. The implementation of the Torque-Action Debris Breaker tool enabled KJO to reduce inventory and overall descaling time.

Microscopic and Fourier transform infrared (FTIR) analysis of the scale determined it was calcite with some small hydrocarbon impurities from either oil or diesel.

The way forward: create a detailed reservoir characterization

The presence of calcite (CaCO3) as a scaling agent is due to the carbonate-rich saturated formation water and the loss of CO2 from this water to the hydrocarbon phase as pressure decreases.

Creating a detailed reservoir characterization that defines fracture orientation, relative aperture produced fluid analysis, and rock properties can help minimize the effect of scale at an early stage. Continuous well monitoring can lead to early identification of scale and determine the need for chemical treatment or further mechanical intervention. This study demonstrates the benefit of using the Peak Torque-Action Debris Breaker tool as the first method of descaling in cases requiring mechanical intervention.

Image of calcite (mid-infrared) chart.
Image of calcite (mid-infrared) chart.
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