There has been a substantial decline in production of wells drilled in Libya over the last 30 years. This sharp, early decline suggests that significantly increased drilling will be necessary in the near future to sustain the country's oil and gas production. With the increasing cost of drilling and completing new wells, attention was focused on the depletion rates and the reasons behind them.

Through offset well data and extensive field knowledge, the producer concluded that the most likely scenario was scale buildup. Data indicated that the scale was barium sulfate (BaSO4), which accumulated in the perforation tunnels, impeding the flow of the hydrocarbons to the production string and, in essence, to the surface facilities.

A cost-effective intervention method to restore the production to the previous producing rates was requested. The intervention would have to be done without suspending the well as well as have the ability to bring back samples of the scale for further testing.

This paper presents a case history of the successful removal of barium sulfate (BaSO4) without killing the well or costly chemical intervention. The method harnesses the effects of dynamic underbalance, sound engineering interpolation, and the versatility of the SurgePro™ software to optimize the job design.

Keywords:
adjacent perforation interval, perforation interval, scale removal, tunnel, upstream oil & gas, intervention, barium sulfate, perforation, dynamic underbalance, information
Subjects:
Perforating, Completion Installation and Operations, Completion Operations
Copyright 2011, Society of Petroleum Engineers
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