16.Gas trap assembly
Th
e
mud trap assembly comprises an electric motor, impeller and trap
chamber. 110 volt power is supplied to the motor from the unit and
the wattage used is monitored to indicate the status of the trap in
the mud. For example, a reduced wattage may indicated that the mud
level has fallen below the trap housing requiring adjustment. The mud
enters the trap through an opening in the base of the chamber where
it is agitated into a vortex by the impeller. The vortex throws the
mud upward on the inside wall of the chamber and liberates entrained
gases. Air is drawn in though an opening in the trap body., mixes
with any liberated gases and is carried via the hose at 6 cubic feet
per hour to the unit. After passing a series of moisture and dust
filters the air/gas mixture is distributed to gas detector,
chromatograph and other ambient detectors ( CO2, H2S etc).
17. Hydrogen sulphide gas detector - h2s
The Crowcon gas detection system is used to select and monitor H2S gas levels at various sensing points at the rigsite. Sensors are usually installed at the bell nipple shale shaker, mud room and rig floor.
A ten channel Gas Warden is used with from 1 to 10 sensors available as needed. The electrochemical sensor contains a sensing electrode, electrolyte, counter electrode and reference electrode. Hydrogen sulphide gas diffusing to the sensing electrode is electrochemical oxidised and at the counter electrode, oxygen supplied from ambient air is reduced. The overall effect of these two reactions is a current that flows through the sensor and into the head amplifier via electrical leads. This current is directly proportional to the concentration of hydrogen sulphide being monitored. To measure H2S which may be dissolved in the drilling fluid a Delphian “Mud Duck” can be made available. This instrument measures the total soluble sulphides, pH and H2S hazard potential. The Mud Duck operates in water base muds with a pH of between 8 and 12. Nevertheless in areas where H2S is known to be a hazard the mud Duck can give the earliest indication of acidic contaminants in the mud.
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Sperry-Sun Drilling Services Basic Mud Logging
Basic Mud Logging
Middle East Training Center 29/06/2014 (Ver. 1.0)