Quality Assurance in Flow Through Oil and Gas Pipelines

Oil and gas pipelines are extensively used in the energy industry. The optimal performance of these pipelines is essential to maintaining energy supply cost-effectively. In downstream operations, flow assurance is of paramount importance. Control valves are vital components of the oil and gas pipelines as they control and regulate the flow parameters. The valves have complex flow areas resulting in the generation of high shear forces which causes strong emulsification in the mixture. This emulsified mixture is difficult to separate and results in extra resources such as additional separation time and chemical additives resulting in a significant increase in the cost of the separation process. In the present work, the effect of the presence of a valve on enhanced mixing in oil and gas pipelines has been quantified. Novel indicators namely, Mixing Coefficient Mc, Modified Mixing Coefficient (MMc) and Velocity-involved Modified Mixing Coefficient (VMMc) based on the in-situ properties have been used for quantifying the mixing behaviour. The computational Fluid Dynamics based globe valve model has been simulated using different velocities and oil volume fractions. Various cross-sectional planes inside the valve and in the straight pipe are created and, Mc, MMc and VMMc are computed at those planes. The mixing behaviour of the valve has been quantified and a considerable increase in the mixing has been observed as compared to the straight pipe. Suggestions have been provided as to how to minimise the mixing effects through the design modifications.