Expandable steel packers navigate wellbore restrictions to isolate openhole sections for acidizing

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Middle East, Iraq, Onshore

Annular zonal isolation packers (AZIPs), using proprietary expandable steel technology, enabled isolating two segments of a carbonate well for acid stimulation. High dogleg severity (DLS) and wellbore restrictions precluded use of conventional swell packers.

Wellbore constraints prevented use of swell packers

An oil well drilled into the Bekhme Formation of Iraq's Tawke Field was stimulated with a limited coiled tubing acid wash in the openhole section. Production results were disappointing, and the operator decided to recomplete the well.

The new completion was designed to compartmentalize two key segments of the well and use sliding sleeves for more precise targeting of the acid to ensure thorough treatment in each segment. However, with DLS up to 28°/100 ft and wellbore restrictions limiting access, the operator's usual practice of using swell packers for isolation in open hole was not feasible.

Robust expandable metal packers provided a solution

SLB recommended its expandable AZIP 0-0, with an element length of 4 ft and slim run-in-hole OD of 5.5 in. The robust packer enables navigating tight spots and high DLS with controlled and limited pushing, pulling, and rotation.

Rapid expansion delivered required isolation for acid stimulation

The packers were run to depth and expanded rapidly in place, eliminating time spent waiting for elastomers to swell. Each segment was then acid stimulated at pressures up to 3,000 psi, with pressure curves demonstrating that the packers provided complete and robust isolation between the two zones.

Schematic of 3 AZIPs isolating 2 openhole sections undergoing acid stimulation through sliding sleeves.
Three annular zonal isolation packers were run into the well past restrictions and tight curves. They were subsequently expanded in place to deliver the isolation required for a multistage acid stimulation operation.
Products Used