Production Monitoring Using Next-Generation Distributed Sensing Systems

Abstract

Distributed ber-optic sensing, and speci cally the introduction of intelligent distributed acoustic sensing (DAS), has gained the attention of production engineers with the promise of a versatile and cost-effective decisionsupport tool. These systems can either be permanently installed, or temporarily deployed using diverse types of intervention systems. This article covers the principles of ow allocation using distributed sensing and show how these can be used and combined to identify uid-entry points, quantify production and identify uid phases. We will describe the methods used to improve quantitative interpretation from distributed sensing, especially the use of phase-coherent DAS for quantitative measurement of sound speed and its use in analyzis of ow velocity and uid phase. While early DAS systems were previously limited in their ow-detection thresholds we have recently introduced a new sensing system, bringing a 20dB (100×) improvement in signal-to-noise. This offers a signi cant improvement in measurement and associated interpretation capability.

A Review of Distributed Fiber–Optic Sensing in the Oil and Gas Industry

“…In the oil and gas industry, the single-point and quasi-distributed fiber-optic sensors have been deployed in many applications, primarily requiring discrete monitoring of acoustics, temperature, and/or pressure along pipelines or downhole, such as managing well drawdown, in-well pressure measurement to determine completion effectiveness, providing pressure build-up data, zonal production allocation, determination of productivity index, and monitoring during well ramp-up [20]- [22]. However, in terms of technology and cost, single-point and quasi-distributed fiber-optic sensors are not suitable for petroleum applications that require continuous spatial sensing, similar to downhole monitoring of hydrocarbon flow [23], fluid injection [24], wax buildup [23], and surveillance of leak detection along pipelines [25].…”

“…Besides the aforementioned advantages of optical fibers, distributed fiber-optic sensors have another major benefit of reducing the overall sensing cost by measuring sensing parameters continuously and in real-time over tens of kilometers. In the upstream sector, distributed fiber-optic sensors are used for a wide range of applications such as seismic profiling [27], hydraulic fracture analysis [28], flow monitoring [23], casing leak detection [29], gas lift optimization [24], diagnosis [23], among others (Fig. 2(a)).…”

Monitoring cold water injections for reservoir characterization using a permanent fiber optic installation in a geothermal production well in the Southern German Molasse Basin

“…Distributed acoustic sensing has been used in downhole applications for structural underground investigations and reservoir monitoring (Barberan et al 2012;Cox et al 2012). DAS has also been used to complement and substitute classical geophones in vertical seismic profiling (Daley et al 2013;Hartog et al 2014;Madsen et al 2016;Götz et al 2018) and has also potential in the field of monitoring production zones (Williams et al 2015;Naldrett et al 2018) and flow characteristics (Bukhamsin and Horne 2016). A broader review of DAS applications in wells is given by Lipus et al (2021).…”

Dynamic motion monitoring of a 3.6 km long steel rod in a borehole during cold-water injection with distributed fiber-optic sensing

“…Bruno et al, 2018 investigate the potential to use downhole DAS data for cross-hole monitoring between two adjacent wells by inducing low frequency pressure pulses to detect high conductivity zones by measuring characteristic vertical strain patterns. Naldrett et al, 2018 compare fiber-optic technology to traditional production logging tools and provides field data examples of flow monitoring based on both DTS and DAS with wireline-type installations. Ghahfarokhi et al, 2019 analyze an extensive data set including borehole geophone and DAS during hydraulic fracturing (cable behind casing) to study micro-seismicity and low frequency events in the borehole.…”