Importance of Downhole Measurements, Visualization and Analysis in Producing Unconventional Wells

Abstract

Production from unconventional shale and heavy oil reservoirs involves dynamic flow environments that can best be managed by use of continuous real-time optimization. Production from shale wells is characterized by rapid decline of rates and slugging phenomena characterized by significant rate and phase fluctuations. Often times, the underlying reservoir inflow contribution along the lateral is not well understood. Fiber-optics-based Distributed Temperature Sensing (DTS) and Distributed Acoustic Sensing (DAS) have been deployed to understand fracture contributions and micro-seismic activities; however, downhole sensing techniques are not widely used to understand production behavior and to control artificial lift systems. Similarly, production from thermally produced heavy oil reservoirs is characterized by fluctuations in temperature distribution and fluid properties. Several operators have installed fiberoptics-based downhole sensing technologies including DTS and Array-Temperature Sensing (ATS) to understand and control steam chamber properties and related sub-cool distribution. Again, use of downhole sensing to manage and control production and production equipment has been somewhat limited and at best qualitative. Both unconventional shale and heavy oil production require artificial lift early in the production cycle; however, approaches to proper selection and management of artificial lift systems are often the result of trial-and-error rather than based on production data. This paper discusses downhole monitoring technologies that can be deployed to provide real-time continuous measurements of downhole conditions in shale and heavy oil reservoirs to help manage production. Unconventional production requires unconventional downhole measurement like DTS, ATS, pressure and temperature sensing in real-time. More important is efficient and effective visualization and analysis techniques to monitor and manage equipment and production. Several case studies are presented that discuss application of real-time downhole measurements coupled with visualization and analysis techniques to achieve improved artificial lift performance, reduced operating costs, and well-managed production behavior leading to improved estimated ultimate recovery (EUR).