Research On Design Method Of Oil And Gas Pipe Type Slug Flow Trap

With the development of two-phase transportation technology, multiphase pipeline have been more and more widely used in the ocean, polar, desert, offshore gas field, which makes slug flow pattern more and more common. Slug flow may affect the normal pipeline transport or makes downstream equipment’s malfunction, so brings slug catcher to separate slugs, store the huge amount liquid and ensure the continuous gas supply of downstream. Slug catchers usually can be broadly classified into two following categories:vessel type and finger type. Some proprietary design methods of finger-type slug catcher are already get in China, but uneven incoming slug flows distribution still exist and conservative conventional design methods may leads low efficiency working of the equipment and sometimes unnecessary cost. So it is very important to improve the work efficiency and at the same time reduce the investment. Main works as following:(1) In this paper, the structure and the working principle of the equipment have been analyzed at first, and then the gas-liquid separation mechanism has been discussed, thus clarify the key parameters.(2) Compared the three typical existing design methods by design finger-type slug catchers at the end of PY30-1 to ZHUHAI submarine pipeline and evaluated the working and economic performance of the structure, then get the main problems of the design methods: incoming flow uneven distribution between fingers, conservative exsiting calculation methods of separation section.(3) Based on multiphase flow field analysis method, combine the distribution coefficient and separation length calculation method with specification of finger-type slug catcher in China, thus updated the design method of the equipment. The flow condition has been modified use OLGA, refine the distribution coefficient of different structure; Use RSM model and DPM model of FLUENT modify the movement and settlement of droplets, which based on two-phase flow theory and computational fluid dynamics. Find out the regulation between droplets travel distances and pipeline diameter, gas density, gas velocity etc. and then get a new calculation of the length of separation section.(4) Evaluated the new method, the result shows that the structure can get the requirement of separation efficiency. Get the conclusion based on the above theoretical achievements:it is possible that slug catcher could performe good at oil and gas separation and reduces the cost at the same time.Through the above research, updated the design method of finger-type slug catcher, expecting to improve design level of finger-type slug catcher and the separation efficiency, reduce the economic investment, to accelerate the realization of finger-type slug catcher design and production localization.