Fiber Optic Based Reservoir Surveillance for Injection Conformance Monitoring and Production Profiling in EOR Fields

Abstract

Petroleum Development Oman (PDO) is increasingly relying on Enhanced Oil Recovery Technologies to optimize production. Successful implementation and operation of polymer flood field developments in Oman involves dealing with a variety of risks that can impact injection conformance, sweep efficiency, production, and surface facilities. The subsurface risks predominantly relate to Fracture propagation, Vertical Conformance and Areal Conformance. Mitigation of these risks is key to enabling economical field developments and requires implementation of adequate surveillance and control measures.Conventional technologies that may be able to acquire the required surveillance data, like production logging, can be costly and/or give unreliable results. In addition, the extreme high well density makes well entries difficult and complicates conventional surveillance. Fiber Optic Surveillance Technologies are most favorable as an alternative because of their potential applicability in water and polymer injectors as well as oil producers; their non-intrusive nature reduces HSSE exposure; and their low cost and automated on-demand time-lapse surveillance potential.Shell and PDO have collaborated on the development of robust interpretation workflows for Distributed Temperature Sensing (DTS) warm back surveys in mature injector wells, and Distributed Acoustic Sensing (DAS) for injection profiling in polymer injector wells and production profiling in oil producers. Data were gathered during various field campaigns as well as in controlled polymer flow loop experiments.This paper presents one successful and one less successful DTS warmback survey conducted in a water and a polymer injector well, and also the recommendations to improve the quality of warmback surveys. Three other datasets are presented, the first two relate to DAS injection conformance monitoring where DAS was acquired in a polymer injector well and used, together with a PLT survey during the water injection periods, to assess the change in injection conformance. The last test relates to a DAS acquisition in an oil producer well equipped with a Progressive Cavity Pump.