Abstract

MOL Pakistan planned to perforate Lockhart Limestone using TCP shoot and pull technique. The lower section of casing was previously perforated for squeeze cementing during remedial job. The conventional hydraulic firing system requires comparatively high surface applied pressures that might jeopardize integrity of squeeze perforations. This could have potentially caused extra cost, time loss and further squeeze jobs. In addition, using high pressure in an already tested well could have resulted in well damage and associated operational risks. Due to this hazard, applied pressure for successful TCP perforation system was limited to less than 1000 psi.

Schlumberger experts collaborated with MOL Pakistan team and considered the unique challenges of the well before recommending an optimized method of perforating. To ensure maximum safety during the operation, the eFire*, electronic pressure pulse operated firing head system with 4-pulse command, was selected as the primary firing head to provide effective low-pressure perforation while saving costs by eliminating the need for a Slickline intervention.

The proposed system provided the flexibility to ensure job execution with a pressure of less than 1000 psi. The job was performed successfully with eFire* playing the key role in safe and accurate manner, by providing the option of low pressure activation.

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