FIT News

Pressure Gauge Test

11 April 2007,

Last Wednesday (11/Apr) two assistants from our lab- Wei and Han, visited the drill site in Dakeng. The case was about the pressure gauge in wellhead A, which cause little problems during first part of mian FIT .

Namely, after 10 days of injection, pressure value on digitizer became very unstable (pic. below).

 

There was a suspicion of short circuits in the gauge plugs caused by humidity in a drill site area. It was confirmed, when dried out plugs worked well without any noise. However after connection the gauge to the wellhead with super-dry plugs, problem appeared again. The gauge was taken to the lab at NCU and sent to Taipei with a complaint. But there again were no any problems with pressure value. Very stable and smooth.

We realized, that the problem occurs only when the gauge is connected to the wellhead. We pointed two possibilies: 1.Chemistry in well-water can make some disturbances for membranes in pressure gauge or; 2.There is some electricity in wellhead making high frequency noise.

Therefore Wei with Han went to Dakeng to our boreholes and plugged the pressure gauge to check again this noise. They confirmed that the noise is caused by electricity in wellhead A. Somewhere, somehow there is little current in pipes (pic. below).

 

To avoid this problem Wei and Han isolated the pressure gauge and wellhead by a rubber hose (pic. below).

 

This idea succeeded (pic. below). Pressure became again stable, so we can continue our project.


Pic.1 High frequency noise (??).
Pic.2 Pressure still unstable.
Pic.3 Isolation by a rubber hose.
Pic.4 Pressure agian stable.