On possibility of remote detection of gas leaks from underwater pipelines using specific slick signatures

Abstract

One of the urgent problems of gas pipeline transport today is the detection of gas leaks in underwater sections of gas pipelines and reducing their negative impact on the environment. This paper is devoted to the development of remote detection methods of gas leaks from underwater gas pipelines by images of slicks above them. A series of laboratory experiments was carried out, in which the structure of average flows in the water column created by flows with different gas flow rates was obtained. The simulation of surfactant removal to the water surface by bubbles was performed by adding sodium dodecyl sulfate (SDS) to the laboratory cuvette at the concentration of 0.5 mg/l. For the surfactant film on the water surface, experimental dependences of its characteristics on the operation time of the bubble pump, such as the surface tension coefficient, elasticity and the relative damping coefficient of small- scale waves under the film, were obtained. It was shown that there are flow convergence zones at some distance from the gas outlet area, which vary depending on the intensity of the gas flow. Surfactant film samples taken in these areas confirmed that over time, the accumulation of surfactants occurs on the water surface. Field experiment conducted in one of the backwaters of the Oka river in the city of Nizhny Novgorod allowed to spot and evaluate the size and shape of the film slick formed around the gas outlet area. The conducted experiments confirmed the formation of a surfactant film spot near the removal area, which indicates the possibility of its remote detection in full-scale conditions, provided the wind near water surface is not more than 2-10 m/s. The obtained data made it possible to get a general idea of the morphology and characteristics of the surfactant spot around the gas outlet from the water.