Publications

Most of Mahakam fields in East Kalimantan, Indonesia, are in mature phase, including Main Zone in Handil Field. Handil Main Zone consists of multiple layers and is characterized by friable to unconsolidated sands with permeability values spanning from hundreds to over 10,000 mD, and highly associated with the presence of coal deposits. This zone is already undergoing Water Injection, where post-water flooding evaluation has revealed substantial remaining oil saturation (ROS), highlighting the potential for tertiary recovery to further maximize production potential.

After thorough analysis, Chemical Enhanced Oil Recovery (CEOR) has been identified as the most feasible tertiary recovery technique for the Handil Main Zone. A critical component in evaluating CEOR is the Capillary Desaturation Curve (CDC), which determines the capillary number at which oil recovery initiates and the threshold at which surfactant efficiency diminishes. The CDC provides essential input for dynamic simulation modeling, enabling optimized design and implementation of CEOR strategies.

However, traditional CDC testing method in laboratory settings which only plays with injection rate has not yielded satisfactory results in Handil case. The high affinity between the reservoir rock and surfactant resulted in an abrupt transition from remaining oil saturation to maximum oil recovery, preventing a gradual CDC formation. To overcome this, an alternative testing approach has been developed, involving adjustments in surfactant concentration and injection rates to more effectively control interfacial tension, hence the capillary number. This modified method resulted in a more defined CDC curve, allowing for precise identification of critical endpoints needed for accurate CEOR modeling and enhanced field application in the Handil Main Zone.