Perforation is a key component in a reservoir inflow to recover the most oil production from a reservoir. In Field S, perforating is typically conducted using the principle of overbalanced technique, which is commonly used in the oil and gas industry and is known to result in higher total skin. This paper discusses the first application of a thru-tubing stand-alone dynamic underbalance technique to clean up perforation tunnels in Field S, Malaysia. The dynamic underbalance(DUB) concept creates a rapid drawdown in front of existing perforation intervals to effectively clean up plugged perforation tunnels, thereby reducing perforation skin and increasing the productivity of the wellbore.

The plunge in the oil price in 2014 has led to a focus on cost reduction and opex optimizationin production enhancement initiativesin Field S from existing well stock inventory. Through this initiative, two strings (Well XS and XS) have been selectedto increase perforation efficiency via thru-tubing DUB application, as part of the cost optimization in our production enhancement portfolio. The project scope covers a full-cycle production enhancement initiative, starting from candidate selection to job design and preparation, job execution and post-job analysis.