Mangala Field Tracer Data Acquisition and Residence Time Distribution Analysis: Results on the Pattern Water Flood and EOR Pilot Area

Abstract

Abstract The Mangala field in the Rajasthan state of western India was the first major oil discovery in Barmer Basin. The heterogeneous upper Fatehgarh (FM-1 and FM-2 sand) is developed with pattern water flooding. The well fluid are produced through Jet Pump (artificial lift) and processed in a plant (Mangala Processing Terminal, MPT). The separated produced water is mixed with Thumbli aquifer water for injection and as power fluid water for Jet Pump. The injection water is heated above reservoir temperature as to prevent any insitu wax deposition. To qualify the support of injector for its pattern producers in heterogeneous multi stacked FM-1 sand, conservative tracers were strategically injected in three crestal patterns of FM-1. The paper discusses the results of inter well tracer test conducted in FM-1 sand of Mangala. The paper focuses on the Residence Time Distribution Analysis of Tracer output signal. To meet the actual field condition of tracer reinjection via processed produced water and tracer addition via powerfluid water circulation, some modification in theoretical assumptions of Residence Time Distribution (RTD) analysis are also suggested. The RTD technique is used to estimate the sweep efficiency/ swept pore volume, and to estimate Lorentz coefficient (Lc). The estimated Lc from tracer analysis matches with the Lc being used in the simulation models. For assessment of EOR potential in Fatehgarh formation, chemical EOR pilot consisting of four injectors and single central producer was conducted in FM-1. Tracers were added in water/polymer/ASP phases of the pilot. The paper compares the sweep efficiency/swept pore volume in three phases of water/polymer/ASP injection with the help of RTD analysis. Better sweep efficiency and more swept volume are observed in polymer phase injection in comparison to the water flooding phase. The paper also focuses on use of qualitative signature of Tracer output for Reservoir Management and Production Optimization.