This paper is intended to describe the design and execution of the first through-tubing gravel pack (TTGP) performed in 2-7/8" tubing in an offshore field in Malaysia, the challenges faced as well as the lessons learned.

Petronas Carigali in Alliance with Schlumberger is currently operating this 25 years old brownfield. Most of its wells were drilled and completed in the mid 1980's and integrity issues are appearing more frequently. The production challenges encountered today range from maintaining stable and profitable rates as well as maximizing reserves and productivity. This must be achieved optimizing operating expenditures and finding solutions that minimize and reduce capital investments.

After close monitoring of production rates it was identified that the well in study was badly underperforming and after some surveys tubing integrity issues were detected in several sections of the production string. This well became a workover candidate and included in the work program and budget for intervention. During the stages of detailed design, an additional opportunity to develop a deeper layer was identified and added to the scope of the workover. Due to the low degree of consolidation of the shallow reservoir sands, this new layer required installation of sand control means.

The TTGP method was selected to access the oil of this prospective sand. This technique allows placement of a gravel pack below existing sandface completions at lower cost compared to a conventional workover intervention.

This paper details the solutions to the challenges faced as a consequence of existing well geometry, integrity and location of the new promising sand.

Despite of the technical and logistic challenges the job was performed below AFE and within technical limit estimates and with a packing factor above design. The TTGP is a low cost solution for sand control in wells with existing completion and behind casing opportunities. The presented well case has served as basis of design for two more wells on the same field and on another well on a neighboring field.

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