SIAM SUDOS-mini 2, Руководство по эксплуатации, Страница: 43 / 64

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2. In the well annulus there is great interference
caused by too strong vibration of the tubing
and casing string, vibration of an electrical
submersible pump (EPS), leaks from valves
and other reasons.
The returning acoustic signal
has a lower amplitude than that
of the noise level.
3. There is much foam in the annulus. The foam absorbs the acoustic
transient signal, and, therefore,
it arrives at the wellhead
significantly alleviated/ at a
significantly lower level.
4.
Either the valve is not open completely, or
the space between the tubing string and the
casing string is too narrow because of hydrate
and paraffin plugs The response acoustic transient
signal is scattered in multiple
changes of gaps.
5. There is a very low (less than 0.5
kilogauss/cm
2
) or a zero excessive pressure in
the annulus whereas the fluid level is at a
great depth (deeper than 1000 m)
The acoustic transient signal
that is generated and returns is
of very low amplitude.
A low fluid level. It is recommended to generate an acoustic pulse
of a shorter duration.
Strong interference, much foam, significant necking of an annulus
gap, low gas pressure in the annulus. It is recommended to generate an
acoustic pulse of a
longer duration.
Very often, especially on wells equipped with an electrical
submersible pump (ESP), the source of very strong interference is acoustic
noise from a delivery line. In this case it is recommended to turn off the
valve on the delivery side of the Christmas tree, if it does not conflict with
safety requirements and the technological process of oil production.
Furthermore it is necessary to place a note warning that the valve is turned
off.
After measurements have been made, the valve should be turned on.
It is necessary to turn on the valve in several stages in order to smooth the
pressure gradually and to prevent breakdown of the pump delivery. When
the valve is opened completely, take the warning note away.