Abstract

The Mangala Field, located in India's Barmer Basin, is a mature, polymer-flooded oil field that requires regular re-evaluation of reservoir performance and sweep efficiency to maintain production levels. Time lapse Pulsed Neutron Saturation log (Carbon Oxygen ratio) has been extensively used for monitoring hydrocarbon saturation variations in the field. Accordingly, perforations or zone changes were optimized to maximize recovery (SPE-211347). This paper proposes a methodology for integrating pulsed neutron saturation data primarily with temperature logs, along with PLT & well correlation, before making a final decision on perforation optimization so that the well starts with low water cut w.r.t. field average water cut. This also serves as an indirect quality check (QC) step for the saturation log (PNL). As the field is under polymer injection, high temperatures indicate injection support from nearby injectors, which correlate with high water saturation from the C/O log. While several papers suggest the use of PNL log for reservoir monitoring, our experience is that cased hole saturation log overestimate water saturations against the perforated zones. This methodology of integrating temperature log with the cased hole saturation log improves interpretation for reservoir surveillance activity. Case studies from the Mangala field show us how this method can be used in many situations, like later completions, better perforation strategies, and converting injectors to producers. These changes can lead to significant increases in production with less water cut profiles. The integrated technique in Mangala field has made recovery more efficient by finding unswept intervals and improving the perforation strategy.