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(11) | EP 0 250 162 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Displacement of free fluid accumulations in pipelines |
| (57) a method of removing at least a substantial proportion of fluid left in a generally
horizontal section of a pipeline, by injecting into the pipeline a pressurized, high
expansion foam and advancing the foam through the pipeline section in contact with
a layer of the fluid left therein to displace the layer towards a remote end of the
pipeline by frictional pick-up of the layer by the foam and to effect mass transfer
of a foaming agent from the foam to the fluid, followed by passing into the pipeline
a pressurized gas to create turbulence in fluid left in the pipeline causing foaming
of the fluid and to displace a substantial proportion of the foam left within the
pipeline. At least some of the bulk of the fluid in the pipeline may be displaced
by injecting the foam so as to establish a transverse foam/fluid interface which is
advanced through the pipeline at or above a minimum velocity required to maintain
said interface leaving a residual amount of fluid which is treated as aforesaid. The
method may include the further subsequent step of injecting into the pipeline a pressurized
foam containing a treatment agent to displace residual foam left in the pipeline,
and then allowing the foam to decompose in the pipeline to deposit the treatment agent
within the pipeline either on the pipewall or in solution with any liquids remaining
therein. |