STM Article Repository

A gas-water system slug velocity was modelled with slug flow like a train of slug units streaming through a steel flowline riser of roughness 0.025 was modelled, the flowline was 2700 m, and the riser was 100 m with a diameter of 0.254 m, with each slug unit having a liquid slug of 100 m and its gas bubble of 200 m. Presumptuously the liquid phase was not compressible; that is, no gas was entrapped in the liquid; there is also no liquid was trapped within the gas. Unsteady state flow was modelled as a mass-spring system with damping. Liquid phase represented the mass, whereas the gas represented the spring and damping as the force of friction that acts on the fluids in motion by the wall. A quasi-steady-state model having a slug velocity of 4 ms-1 was used to simplify the numerical correlations and algorithm and to relate with outcomes of the unsteady state model. Outputs from both models show that pressure and rate vary sinusoidally at fixed points in the system. Both models are unconcealed that the velocity of every slug unit was most at the end of flowline to the separator. The result from the transient state model is complex for weighing up with other results from the literature. This procedure was as a product of over-simplification owing to some assumptions made. Also, simultaneous solutions to the differential equations were solved with hand. It is determined that quasi-steady-state outputs are more reliable than the unsteady state model for flowlines that are not situated on heaving surfaces because the model is less complicated and follows the predictable trend.