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degasser
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DEGASSER TECHNOLOGY:
The key for good data
Gas Line
SpareGas Line
DryingAgent
Total GasDetector
Chromato-graph
CompressedAir Supply
Vent
Vent
CalibrationSystem
RecordingEquipment
Degasser
LoggingUnit
Return Mud FlowFrom Well
In-lineH S Sensor2
Pump
Pump
Surface gas detection processThere are 3 main parts to any gas detection service today and Geoservices have focused on all of them.
Gas Extraction
Gas Transport
Gas Analysis We measure the amount of extracted gas in the gas air mixture , at the trap suction: It is a gas in Air measurement
Variables in measurement: Losses of gas along flow lineVariables in measurement: Losses of gas along flow line
Misrepresentation of gas composition far from well head
OUT
IN
Flow line not full.Turbulences -Mixing with air
Losses at bell nipple. Degassing depends on molecular weight
Open flow lineSpontaneous degassing
Flow line data104
103
102
10
1
Shales shaker data104
103
102
10
1
Time (A.U.)
Time (A.U.)
Spontaneous degassing of mud decreases gas quantity far from well head
Change gas composition: heavier remains longer in mud than lighter
Gas
qua
ntity
(ppm
)G
as q
uant
ity (p
pm)
C1C2C3iC4nC4iC5nC5
Impact of degasser position
Rotor CouplingPlate
ConnectionBox
Gas/airOutlet
CylindricalTank
Decanting Tube
CheckValve
Float
Motor
Air Inlet
Mud Outlet
RecommendedMud Level
Degassing Chamber
Rotor Blade
Tubular Mounting Arms
Rubber Hose,12mm I.D.
Rubber Hose,8mm I.D. To Mud Logging Unit
Installed at Shaker header boxNo volume or flow control
Conventional gas extractor
Constant VolumePump
Motor driving both Agitator and pump - Constant ratio
Gas Outlet
Self cleaning mud intake probe
Sealed extraction chamber
Installed in the flow line
Constant mud and air flow rate
Increased extraction efficiency
Qualitative gas extraction
Constant volume gas extractor
The benefits of a constant volume trapThe benefits of a constant volume trap
106
105
104
103
102
10
106
105
104
103
102
10
Conventional degasser
Constant volume degasser
Time (A.U.)
Time (A.U.)
Gas
qua
ntity
(ppm
)G
as q
uant
ity (p
pm)
TGC1C2C3iC4 and nC4 (dashed)iC5 and nC5 (dashed)
Conventional degasser: spurious peak due to mud level fluctuations
Constant volume degasser: no spurious peak, consistent with fluid reservoir composition
106
105
104
103
102
10
105
104
103
102
10
1Time (A.U.)
Time (A.U.)
Gas
qua
ntity
(ppm
)G
as q
uant
ity (p
pm)
TGC1C2C3iC4 and nC4 (dashed)iC5 and nC5 (dashed)
Conventional degasser
Constant volume degasser
Conventional degasser: decrease of gas detected due to inadequate supply of mud(Trap Starvation)
Constant volume degasser: no decrease of gas quantity, consistent with fluid reservoir composition
The benefits of a constant volume trapThe benefits of a constant volume trap
Constant volume/temperature fluid extractor (Flex)
Repeatable gas extraction
Gas In correction
On site extraction calibrationSealed Extraction Chamber
Heater
Mud Level Sensor
Self Cleaning Mud Intake Probe
Pump
Temperature sensors
Constant volume
Constant Temperature
Constant Air/Mud Factor
Specially designed mud outlet
RPM sensorsConstant Agitation speed
1st difference: volumetric/flow rate ratio difference
0.670.5 l/min0.3 l/minFlex
30.5 l/min1.5 l/minGZG
Ratio of Mud Flow/Gas FlowAir flow rateMud Flow
rateDegasser
Assuming any other parameters constant, concentrations of extracted gas expected to be 4.5 times less with Flex compared to GZG
For light components, GZG can have higher readings than Flex …
÷ 4.5
Improved gas extraction: air and mud flow rate
2800 rpmFlex
1300 rpmGZG
StirringDegasser
2nd difference: stirring 3rd difference: temperature
70°C(WBM)/90°C(OBM)Flex
No control/regulationGZG
Mud temperatureDegasser
Higher mud/gas contact area with Flex
Higher and constant stirring rpm thus increases exchange kinetics
Shift equilibrium to higher gas concentration
Increase exchange kineticsReproducible gas extraction conditions
Improved gas extraction: agitation and temperature
GAS OUT
GAS IN
Positioning Flex Out and In probes
Extractor designed for Deep Water condition
FLAIR Deep Water DataStandard Deep Water Data
High light components readingsNo C3+ readings
Fluid data up to C5 and more
Standard measurements overestimate light HC components
C3+~0
Good heavies
Coherent ratios
C1-C8 boiling points
liquid80.1 °C6H6Benzene
liquid126 C8H18octane
liquid98.4 C7H16heptane liquid68.7 C6H14hexane liquid36.1 C5H12pentane
gas-0.5 C4H10butane
gas-42.1 C3H8propane
gas-88.6 C2H6ethane
gas-162 CH4methane
State (25oC, 101.3kPas
Boiling Point (oC) Molecular Formula Name
Deep Off-shore Mud temperature 15 °C
Extractor designed for Deep Water condition
Standard Deep Water Data FLAIR Deep Water Data
Conclusion: Degasser evolution from Gas Trap to Fluid Extractor
Repeatable gas extraction
Gas In correction
On site extraction calibrationConstant mud and air flow rateIncreased extraction efficiencyQualitative gas extraction
No volume or flow control