The Optic Oil Field: Deployment and Application of Permanent In-well Fiber Optic Sensing Systems for Production and Reservoir Monitoring

Abstract

Abstract Development and exploitation of oil and gas resources in increasingly difficult operating environments such as deepwater raise many technical challenges. Among these is the ability to provide assurance on the completions and production from high-cost and complex wells. Real-time, permanent wellbore and reservoir monitoring is a critical technology for providing assurance and maximizing profitability of these fields. Recent developments in fiber optic sensing technology have resulted in reliable alternatives to conventional electronic systems for permanent, downhole production and reservoir monitoring. In-well fiber optic sensors are now being developed and deployed in the field for measuring temperature, pressure, flow rate, fluid phase fraction, and seismic response. Bragg grating-based fiber optic systems combine a high level of reliability, accuracy, resolution and stability with the ability to multiplex sensors on a single fiber, enabling complex and multilateral wells to be fully instrumented with a single wellhead penetration. These systems are being installed worldwide in a variety of operating environments for a variety of applications. This paper presents several recent deployments of in-well fiber optic monitoring systems, including descriptions of the downhole sensor assemblies, installations, and measured data. Installations of fiber optic pressure and temperature systems in a land well and in the Gulf of Mexico and an all-fiber flow and liquid fraction system in deepwater Gulf of Mexico are discussed. A general description of fiber optic sensing and Bragg grating-based sensing systems is also presented.