Abstract

Formation damage caused by organic and inorganic deposition particularly near and around wellbore, can substantially reduce the hydrocarbon production. In depleted oil reservoirs, when reservoir-driving forces are low and in declining stage, even small resistance can restrict the fluid flow resulting in loss of well productivity. Single stage chemical system was designed to restore the oil production of Malaysian oil producers that suffers with complex deposition problems. Extensive well selection activities and laboratory analysis were conducted prior to the well treatment.

This paper presents five case studies of treated wells that have been revived or boosted using the single stage chemical system. The well treatment consist of bull-heading a pill of pre-flush to facilitate the action of the main chemical system, followed by the main chemical, soaking for 24 hours and flow back the well. The well treatment job was completed successfully and safely with chemical cost saving of 40%. Post well treatment showed mixed results by instantaneous average production improvement of more than 400% for Well BK1, BK2 and BK3 and 26% production gain for Well BT2. The improved production sustained up to five months before a drop in production back to the old trend. Well BT3 wellbore damage was partially removed with less incremental in terms of gross production post treatment.

Primary hypothesis of short sustainability of the post well treatment is likely due to re-deposition of wax within the subsurface environment. Confirmation on this hypothesis is planned through slick line intervention. The instantaneous production gain highlighted the opportunity to replicate the technology with improved method by incorporating the inhibition chemical component to other potential wells that face similar deposition problem through proactive and preventive approach to ensure production sustainability and minimize the number of idle wells.

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