Abstract:
More
and more transient gas-liquid operations in pipes are being successfully applied in the oil
and gas industry. Pigging in two-phase pipelines, to remove liquid accumulation or for cleaning
purposes, is an important transient operation. Another important operation is the injection of (-)-as
to transport the accumulated liquid in the pipeline to process facilities. Analysis of such transient
two-phase flow in a pipeline is necessary not only for designing the liquid and (Yas handling
facilities, but also for safe operating procedure. In pipeline-fiser system such operations cause
even more severe changes in flow conditions.
A two-fluid model has been developed to determine the transient behaviour of fluids during these
operations.T he derived one-dimensionasl et of equationsf or each flow pattern describet he flow
of fluids in all regions. Semi-implicit finite difference schemes were used to solve the initial and
boundary value problem for each phase of the process- gas/pig injection, gas shut-in, slug
production and gas flow out of the system.
An extensive experimental program has been carried out to acquire two-phase transient flow and
pigging data on a 67 m long, 0.0525 m diameter, 9.9 m high pipeline-riser system. A computer
based data acquisition system has been utilised to obtain rapidly changing and detailed information
of the flow behaviour during the transient tests. The model results compare well with the
experimental data for characteristics such as inlet pressure, hold-up and pig velocity.
