Well-testing heavy oils

We have a client who is about to start a heavy oil drill stem
test in the UK sector of the North Sea.

Analysis of the oil sample recovered on wireline shows its viscosity
is strongly related to temperature.

We are confident that it will flow at reservoir conditions, but there
is a reasonable chance that flow to surface may be compromised by the
low temperature in the riser area.

Therefore we are asking everyone to put their thinking caps on and
see if we can come up with a flow assurance technique to improve
chances of the well flowing to surface.

Areas for thought:

Can we get any insulated test tubing?

Can we get any insulated riser?

Could we circulate hot mud or brine down the choke/kill/booster lines
and back up the riser? Are there any umbilicals or other issues on
the flow riser that would prevent this?

If the hot fluid cools going down the choke/kills, would it be better
to close diverter and pump heated fluid down the riser and back up
the lines?

When running the test string, should we fill the prodn tubing with
e.g. diesel/base oil to improve viscosity of the initially produced
oil when the riser is fully cold?

If we get a viscous plug of cold heavy oil, are there any chemicals
we can use to dissolve the plug?

Would appreciate any ideas and feedback to be posted on the Forum..
and/or onpass to anyone else who can help

Thanks

Dave Taylor

2 Answer(s)

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