Experimental Study On The Flow Characteristics Of Oil-Gas Two-Phase Slug Flow In Horizontal Pipeline

Slug flow is one of the most typical and common regimes of oil-gas two-phase flow in transportation pipelines. This intermittent flow would induce the liquid hold-up and the pressure in the system to fluctuate. As the pipeline for oil-gas transportation is operated in this regime, an intense fluctuation of liquid level in oil-gas separators at downstream of the line would be caused when a liquid slug leaves the end of pipeline. In order to increase the safety and optimize the conditions and operation of pipeline and oil-gas separators, it's very important to analyze the characteritics of the regimes, especially the slug flow regime.By detailed analysis and using a methodology developed specifically for this study, the observed flow patterns were classified into stratified smooth, stratified wavy, bubbly, slug, and Pseudo-slug flow regimes. Based on the experimental data obtained in this study and on comparison with published flow regime maps, a flow regime map was presented to predict the prevailing flow regime for oil-gas flows in small diameter horizontal pipe at near-atmospheric conditions.The pressure and differential pressure characteristics of three types of flow regime were studied. They are stratified smooth flow, stratified wavy flow and slug flow. A method for the measurement of the characteristic parameter of slug flow was introduced according to the pressure and differential pressure characteristics of slug flow.By comparing slug flow with Pseudo-slug flow, both slug flow and Pseudo-slug flow can cause intermittent block in the pipeline. There are three different characteristics between them. On the gram of Pressure fluctuation in timing, slug flow has a maintain character what Pseudo-slug doesn't have. the pressure amplitude and slug velocity of Pseudo-slug are significantly lower than those of slug flow.Experimental study on the characteristics of oil-gas two-phase slug flow in the horizontal pipeline was done. By analyzing the experimental data, the value and the law of the characteristic parameters were derived. Based on linear regression and other data-processing methods, the expressions of the slip coefficient, slug length, slug frequency are derived.By simplifying the slug unit model, according to Taitel-Dukler two-fluid model, conservation of momentum and pressure drop between gas and liquid, a theoretical prediction was done to slug lenth and the product of slug length and slug frequency. The predicted values are substantiated to be acceptable.