Dynamic Reservoir Characterization of Naturally Fractured Reservoirs from an Inter-Well Tracer Test: A Case Study

摘要

After redevelopment of a field located in the Spraberry Trend Area, an inter-well tracer test was conducted in 2011 at the field scale in order to understand the fracture system which forms preferential flow paths, and for better management of waterflooding. The test consisted of 13 injection wells and 110 producing wells that were sampled, with each injector having its own unique water tracer. The test generated 598 tracer responses from 52 out of the 110 sampled wells. A wide range of tracer velocities from 14 ft/day to ultra-high velocities exceeding 10,000 ft/day with same-day breakthrough was observed. Re-injection of produced water has caused the tracers to be re-injected and added an additional challenge to diagnose tracer responses affected by water recycling. In this study, a comprehensive workflow is presented for dynamic reservoir characterization of naturally fractured reservoirs from an inter-well tracer test by incorporation of analytical interpretation and streamline simulation. Prior to numerical simulation phase, tracer responses were categorized and mapped in accordance to analytical interpretations. The dominating flow trends were detected in E-W and NE-SW directions, where only the NE-SW direction was observed from inter-well tracer test conducted in E.T. O'Daniel lease in 2000. Then, a dual-porosity streamline simulator was used to match both historical production and tracer responses. Historical production performance and tracer responses of an inverted nine-spot pattern were matched and taken as a case study to understand matrix-fracture transfer mechanism, matrix capillary pressure and fluid distribution in the field where no information exists other than dynamic data.