EVOLUTION OF OIL AND GAS JET FLOWING THROUGH RUPTURE OF MAIN OIL PIPELINE (GAS PIPELINE) LOCATED ON BOTTOM OF WATER RESERVOIR

• Main Authors: Svetlana R. Kildibaeva, Iljas K. Gimaltdinov
• Format: Article
• Language: Russian
• Published: Tomsk Polytechnic University 2020-05-01
• Series: Известия Томского политехнического университета: Инжиниринг георесурсов
• Subjects: submerged jet; multiphase jet; hydrate; methane; oil; hydrocarbon spill; control volume method; gas state equation
• Online Access: http://izvestiya.tpu.ru/archive/article/view/2651/2233
• ISSN: 2500-1019; 2413-1830

The relevance of the research is associated with increasing interest in production of hydrocarbons at the bottom of the world ocean. The risk of accidental spills of oil products into the water increases many times. Oil spills on the Ixtoc-1 platform and Deepwater Horizon in the Gulf of Mexico demonstrated the unavailability of modern methods to eliminate emergency underwater leaks. In this regard, there is a need to study the submerged jets consisting of hydrocarbons mixture (oil and gas). In addition, deep-sea spills of a multiphase mixture of oil and associated gases can produce hydrates, which can affect the dynamics of these emissions. Therefore, the study of the multiphase jets dynamics in ocean water accompanied by hydrate formation is an urgent and multifaceted task. This study will reduce the time of elimination of possible leaks. In this work we study a submerged multiphase jet formation taking into account hydrate formation under different initial conditions. The main aim of the research is to investigate the formation of a submerged jet depending on the initial conditions. Objects: multiphase jet of hydrocarbons; components of the jet: oil, gas, water; composite bubbles, covered with a hydrate shell; nature of jet flow spread, hydrate formation. Methods. The integral Lagrangian method of the control volume is used to describe the submerged jet propagation. According to this method, the jet is represented as a sequence of elementary volumes, each of which is characterized by linear dimensions and thermophysical characteristics. Submerged jet distribution is considered for deep-sea spills, which corresponds to the case when hydrate shells begin to form on the surface of the bubbles and the gas bubble turns into a hydrate. The paper adopts a limit scheme, according to which hydrate formation is limited by the diffusion of gas through the hydrate shell. Result. The authors have supplemented the mathematical model of multiphase submerged jet flow taking into account the formation of hydrate on the surface of bubbles. The dependences of the submerged jet thermophysical characteristics on vertical coordinate and the trajectory of jet propagation are obtained. The equation of state for real gases is applied for methane bubbles, which are covered with a hydrate shell. As a result of calculations, the dependences of the radius of the gas and hydrate component of the composite bubble and its density on vertical coordinate are obtained. It is found that the radius of the bubble hydrate component decreases for the case when the gas is described by the ideal gas state equation and grows for the case of applying the equation of state for real gas.