In order to investigate the phenomenon of gas⁃liquid bias in parallel separators in oil⁃gas gathering and transportation system, an experiment facility for gas⁃liquid two⁃phase splitting was designed, constructed and instrumented. Flow rates, pressure, pressure drop，liquid level and liquid holdup were measured and recorded by data⁃acquisition system. Gas⁃liquid splitting pipelines of two geometries (horizontal pipeline⁃T junction⁃ horizontal pipeline and horizontal pipeline⁃T junction⁃vertical pipeline) were constructed. Experiments on splitting of slug flow were carried out and splitting characteristics of gas⁃liquid were studied with symmetrical and asymmetrical pipeline conditions. When the pipeline conditions are symmetrical, the two phases of slug flow splitting into two separators are even for pipelines of two geometries. When the pipeline conditions at the outlets of separators are asymmetrical, mal⁃distribution of both two phases occurs and liquid tends to split more evenly than gas. Based on the calculation of pressure drop, a splitting model was established and the influence of gas⁃liquid velocity on the flow characteristics was explained simply.

The offshore natural gas condensate wellhead platform has the characteristics of limited space, far from land, no permanent staff and high maintenance cost, which poses a higher challenge to the desanding equipment and technology. In order to solve this problem, a compact tubular sand removal equipment with small volume is proposed.The performance of the sand removal device is evaluated with pressure drop, mass separation efficiency and particle separation efficiency as evaluation indicators. The results show that the mass separation efficiency increases rapidly in the process of the separation chamber diameter changing from D1 to 2D1. Continuing to expand the diameter of separation chamber, the increasing trend of mass separation efficiency decreases and the pressure drop of sand remover increases rapidly; The desander with two⁃stage separation structure has obvious improvement in separation performance, and the mass separation efficiency has been increased by more than 20%. Comparing the particle size of separated gravel with the critical particle size of pipeline carrying sand and the critical particle size of wellhead safe operation, it can be concluded that the separation efficiency of large grain gravel can reach more than 80%, and the tubular desander can complete the pre⁃separation task of offshore wellhead platform gravel.