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Shipboard Acoustic Observations of Flow Rate From a Seafloor‐Sourced Oil Spill
Author(s) -
Loranger Scott,
Weber Thomas C.
Publication year - 2020
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2020jc016274
Subject(s) - petroleum seep , canyon , geology , volumetric flow rate , seafloor spreading , echo sounding , environmental science , flow (mathematics) , current (fluid) , methane , geomorphology , remote sensing , oceanography , mechanics , ecology , physics , biology
Abstract In 2004 a debris flow generated by Hurricane Ivan toppled an oil production platform in Mississippi Canyon lease block 20 (MC20). Between 2004 and the installation of a containment system in 2019 MC20 became an in situ laboratory for a wide range of hydrocarbon in the sea‐related research, including different methods of assessing the volumetric flow rate of hydrocarbons spanning different temporal scales. In 2017 a shipboard acoustic Doppler current profiler (ADCP) and high‐frequency (90 to 154 kHz) broadband echosounder were deployed to assess the flow rate of liquid and gas phase hydrocarbons. Measurements of horizontal currents were combined with acoustic mapping to determine the rise velocity of the seep as it moved downstream. Models of the rise velocity for fluid particles were used to predict the size of oil droplets and gas bubbles in the seep. The amplitude and shape of the broadband acoustic backscatter were then used to differentiate between, and determine the flow rate of, hydrocarbons. Oil flow rate in the seep was estimated to be 56 to 86 barrels/day (mean = 71 barrels/day) while the flow rate of gaseous hydrocarbons was estimated to be 98 to 359 m 3 /day (mean = 229 m 3 /day).