Distributed Acoustic Sensing (DAS) Response of Rising Taylor Bubbles in Slug Flow

Abstract

Slug flow is one of the most common flow types encountered in surface facilities, pipelines, and wellbores. The intermittent gas phase, in the form of a Taylor bubble, followed by the liquid phase can be destructive to equipment. However, commonly used point flow sensors have significant limitations for flow analysis. Distributed acoustic sensing (DAS) can turn optical fibers into an array of distributed strain rate sensors and provide substantial insights into flow characterization. We built a 10 m vertical laboratory flow loop equipped with wrapped fiber optic cables to study the DAS response of rising Taylor bubbles. Low-passed DAS data allow for velocity tracking of Taylor bubbles of different sizes and water velocities. Moreover, we measured the velocity of the wake region following the Taylor bubble and explored the process of Taylor bubbles merging. The amplitude analysis of DAS data allows for the estimation of Taylor bubble size. We conclude that DAS is a promising tool for understanding Taylor bubble properties in a laboratory environment and monitoring destructive flow in facilities across different industries to ensure operations are safe and cost-effective.

Polar Decomposition of Jones Matrix and Mueller Matrix of Coherent Rayleigh Backscattering in Single-Mode Fibers

“…Eventually, the Jones matrix J RTS has been decomposed into a unitary matrix U in the form of Equation ( 14) and a Hermitian matrix H in the form of Equation ( 5). The matrix elements in U and H have been expressed in terms of the optical phase φ and the forward Muller matrix elements m j , j = 7, 8, 9 through Equations ( 2), ( 3), (10), and (12).…”

“…The matrix elements w 0 , w 1 , w 2 , and w 3 have already been defined in Equation (10). The rest of the matrix elements are [24]…”

“…φ-OTDR was proposed firstly for distributed intrusion sensing [ 1 , 2 ]. Since then, it has been used for structure health monitoring [ 3 ], partial discharge locating and detecting [ 4 ], railway monitoring [ 5 ], downhole measurement [ 6 ], traffic monitoring [ 7 ], pipeline leakage detection and localization [ 8 ], earthquake detection [ 9 ], rising bubble measurement [ 10 ], and many other applications [ 11 ]. In particular, by using submarine fiber-optic cables, φ-OTDR is used for hydroacoustic signal detection [ 12 ], submarine structural characterization [ 13 ], coastal safety [ 14 ], water column and sediment monitoring [ 15 ], near-field target localization in shallow water [ 16 ], etc.…”

Characterization of Gas–Liquid Two-Phase Slug Flow Using Distributed Acoustic Sensing in Horizontal Pipes

“…The method is used for oil producers with low producing rates where the DTS was utilized to measure steady-state borehole temperatures, and the DAS is used to measure transient borehole flow velocities by tracking the signals generated by thermal slugging. This research was further developed for liquid and gas two-phase flow, specifically for gas–oil two-phase slug flow [ 17 , 18 , 19 ]. The experiments’ findings using a vertical flow loop indicated that the acoustic and thermal signals measured by DAS are sensitive to low air injection.…”

Experimental and OLGA Modeling Investigation for Slugging in Underwater Compressed Gas Energy Storage Systems

“…Currently, Significant progress has been made in investigating the flow characteristics, motion laws, influencing factors, and other aspects of slug flow through numerical simulation [19][20][21], laboratory testing [22][23][24], and field observation [25][26][27]. Furthermore, some studies are dedicated to developing innovative technologies and devices for preventing and mitigating slug flow, which can enhance the effectiveness and safety of transport pipelines.…”