The operator’s goal

A gas injector well was to be converted into a producer well. A workover program was planned to cut and change the existing tubular, including setting a standard plug to isolate the lower zone.

The wellbore had a 75° deviation at 4,283-m [14,052-ft] MD with a minimum restriction of 4.313 in at the nipple. The lower-profile sealbore provided an insufficient barrier and limited the deep-set plug development for the lower zone. And additional risks involving a severing operation, which had blocked the retrieving process, were identified.

The operator needed to create a gas-tight seal in a 5½-in, 320-kg/m3 [20-lbm/ft3] liner in a challenging HPHT environment with pressures up to 35 MPa [5,076 psi] and temperatures up to 152 degC [306 degF]. To minimize workover time and cost, alternative e-line rigless intervention options were pursued.

What was tried first

Traditional deep-set plugs did not meet the expansion requirement for the current working envelope, and a cementing operation was not a viable option to provide a consistent and homogenous barrier at such deviation and temperature.

What Schlumberger recommended

The SIMultra retrievable bridge plug was deployed using the TuffTRAC cased hole services tractor. Certified to ISO 14310:2008 grade V0 and quality grade Q1, the SIMultra retrievable bridge plug incorporates a proprietary hybrid metal-elastomer seal to create a well barrier with both exceptional reliability and retrievability. Suited for HPHT operations, it is performance rated to 177 degC [350 degF], 69 MPa [10,000 psi], and extreme CO2 sour service capability.

Using metallic support plasticity to close the extrusion gap during the setting process, the elastomeric compound of the historically high shearing stress is freed—unlocking sealing performance to a completely new stage.

What was achieved

The successful gas-tight isolation using the SIMultra plug enabled cutting the tubing properly, and the rigless intervention saved 4 rig days, reducing workover costs.