Abstract
This case history describes a procedure in which a polymer sealant and a bridge plug were used to shut off water production from upper zones to enable gas production from productive lower zones. Offshore gas fields operated in East Kalimantan were producing gas and water. When water production increased, gas production was greatly reduced. This paper presents a case history of water-shutoff work performed in the Peciko field, offshore East Kalimantan, Indonesia.
Typically, the production of these wells is commingled with multiple perforations inside the production casing and the water breakthrough could happen at any layer; therefore, a selective shutoff is required. A production-logging tool (PLT) was run to identify the source of the water influx, and the uppermost set of perforations was identified to be the main contributor to the water production.
The objective was to completely shut off the uppermost zones with sealant, without a cement tail-in. The chosen sealant was an organically crosslinked polymer system and tail-in with a particle-gel system (PGS) to increase near-wellbore shutoff integrity. Because the target shutoff zone was the uppermost set of perforations, a retrievable bridge plug was used to provide isolation from all the lower zones while pumping the sealant.
The operation sequence consists of (1) setting the retrievable bridge plug, (2) performing an injectivity test, (3) pumping the sealants, (4) shutting-in to allow the polymer to develop strength, (5) cleaning out excess particle gel inside the wellbore (without milling), (6) retrieving the bridge plug in an underbalanced condition, and then (7) flowing the well.
The job was initially evaluated by flowing the well and observing the well performance. Later, a PLT was run to confirm the amount of influx from the shutoff zone. Results from both were very satisfactory, as is detailed in the paper.
