The objective of the proposed three-year effort will be to develop a fiber-optic sensing system capable of real-time simultaneous distributed measurement of multiple subsurface, drilling, and production parameters. A proven and breakthrough technology that enables the harmonic-free interrogation of thousands of grating-based distributed interferometers along an optical fiber will be leveraged for long distance, distributed acoustic measurements, and integrated with a novel optical sensing fiber to obtain distributed subsurface electromagnetic field measurements. A novel multi-material, measurand-specific, optical fiber will be fabricated and integrated with the sensing system to enable the distributed and real-time measurement of multiple parameters simultaneously with ultrahigh sensitivity, high frequency, and reliability at depths and temperatures beyond that of current monitoring technologies.
Virginia Polytechnic Institute and University, Blacksburg, VA 24061
Sentek Instrument LLC., Blacksburg, VA 24060
It has been estimated that the recovery efficiencies are on the order of 20% in gas-rich shale reservoirs and less than 10% in liquid-rich plays. Critical knowledge gaps in the understanding of subsurface hydraulic fracture geometry and optimal completion/stimulation strategies continue to limit the most efficient recovery of Unconventional Oil and Gas (UOG) resources. A major obstacle to understanding the in situ nature of hydrocarbon occurrence and the resultant flow properties of the stimulated reservoir and controlling stimulation and production is the limitations of the technologies currently available to clearly characterize and monitor the subsurface features.
Next-generation logging tools that can image radially from the borehole with high resolution, seismic sensor arrays to monitor stress near the wellbore, and methods to remotely characterize fluid flow are actively sought to assure efficient production. Although several schemes (such as wireless data telemetry, electronics-based technologies, and fiber optic sensors) have been investigated, insufficient performance has limited their efficacy in UOGs. Furthermore, the use of more than one of these technologies to obtain the necessary information further complicates the deployment and is often not feasible because of the stark difference in operating principles and integration procedures. There is a clear need for innovative and breakthrough technologies for improved subsurface characterization, visualization, and diagnostics to fill data gaps in big data analytics to inform decision making and improve ultimate recovery of UOG plays.
The project will demonstrate a ground-breaking technology to view the subsurface with unprecedented clarity, enable real-time facture diagnostics, and optimize drilling and production via the rapid, distributed, and simultaneous measurement of subterranean seismic and electromagnetic phenomena. A one-of-a-kind distributed fiber optic acoustic sensing system will be coupled with a transcendent magnetic fiber optic sensing fiber that will provide seismic and electromagnetic measurements with contrast, spatial resolution, and functionality not yet realized by other techniques. It is envisioned that the simple, minimally invasive, compact, and cost-effective approach will aid in the ultimate recovery from UOG resources and optimal use of the Nation’s subsurface resources, particularly for the small profit margins and fast turnaround time required for decision-making at these sites.
The project team’s efforts have been focused on the development of the project team, execution of the subaward to Sentek Instrument, performing a literature/market review, theoretical analyses and modeling of the magnetic sensing fiber, and the acquisition of raw materials for the fabrication of the special magnetic sensing fiber and components for the optical interrogation system.
Upon project commencement on October 1, 2019, the research team prepared and presented a technical and management overview to DOE at the Project Kickoff-Off on October 29, 2019. A graduate (Ph.D.) student was successfully recruited to join the project team and has begun a literature review and will lead the theoretical analysis and modeling efforts required for sensor performance optimization.
The subaward agreement to support the work to be performed by Sentek was fully executed on November 8, 2019, and Sentek has begun to identify and acquire the necessary components to construct the multi-parameter sensor interrogation system. The research team at Virginia Tech initiated a literature and market review to fully understand the technical sensing requirements for downhole applications. Work was initiated to develop the theoretical analysis and modeling techniques that will be utilized to optimize the fiber waveguide and sensor design.
The raw materials necessary for fiber fabrication — including the fused silica tubing and magnetostrictive precursor materials (nickel, Terfenol-D™, Metglas®) — were acquired, and initial experimentation has been performed to optimize the parameters for drawing of the magnetostrictive rods that will be inserted in the sensing fiber preform. Furthermore, the optical core rods have been acquired, and a process necessary for insertion in sensing fiber preform has been successfully developed.
Phase 1 – DOE Contribution: $466,512
Phase 2 – DOE Contribution: $518,593
Phase 3 – DOE Contribution: $514,895
Planned Total Funding – DOE Contribution: $1,500,000
Phase 1 – Performer Contribution: $125,000
Phase 2 – Performer Contribution: $124,999
Phase 3 – Performer Contribution: $125,001
Planned Total Funding – Performer Contribution: $375,000