Publications

Ujung Pangkah is a carbonate field located in Indonesia and being operated by SAKA Indonesia Pangkah Limited (SIPL). Several technical challenges were identified in this field including: 1) Multilayer zone wells with high permeability variations and possible presence of natural fractures in a complex geological environment. We can see a very tight, poor and good permeability in each production well. 2) Highly deviated to horizontal trajectory wells. 3) There are no mechanical barrier between tight and high permeability gas zone. All the factors above present a challenge to achieve uniform stimulation throughout the interval. Conventional matrix stimulation treatment such as acid bull heading had been applied, however, optimum result was not achieved due to the acid placement issues. Moreover, the situation becomes more challenging in depleted heterogeneous reservoirs with high permeability variations, the presence of natural fractures in a complex geological environment, the absent of mechanical barrier between tight and high permeability gas zones, and the completion schematic uniqueness. The completion type of producing wells is also challenging for acid stimulation. Multi zones behind Sliding Sleeve Door (SSD), multi zones with different SSD, multi zones with long gap interval, and multi zones with communication behind the tubing production are such the examples of completion type in Ujung Pangkah field. In this paper, we present the combinations of various fit purpose technology to achieve effective diversion and effective stimulation to unlock production potential in Ujung Pangkah field. Coiled tubing technology application, viscoelastic surfactant (VES) based diverting system, and modified pumping schedule based on each well completion type are combined for matrix treatment of carbonate formations. The new methodology improved the acid placement and treatment coverage to all producer interval and minimizing risk of liquid unloading problem post treatments. This approach has successfully unlocked the production potential in tight gas zone and increased the productivity of high permeability zone. The effectiveness of this system was confirmed in more than 20 production and injection wells in Ujung Pangkah field. In fact, gas production in one of the wells was successfully improved by 200% following the treatment.