1. Gas migration
What if we delay the kill operation
E.Abdullah Mahmoud YouTube: Petroleum Capsules
Email: PE.abdullah36@gmail.com FB: www.FB.com/abdullah.amar
Presented by “Petroleum Capsules” Channel on You tube
2. • Gas is lighter than the mud and will try to
migrate up the hole.
• The speed of migration will depend on;
– mud properties- weight and viscosity
– hole angle
• The gas cannot expand so will carry Formation
Pressure upwards causing ;
SICP to increase
BHP to increase
SIDPP to increase (if no Float)
Gas migration
E.Abdullah Mahmoud YouTube: Petroleum Capsules
Email: PE.abdullah36@gmail.com FB: www.FB.com/abdullah.amar
3. How Can You See Gas migration
0
200
400
600
800
1000
Time
pressure
Shut In Pressure
E.Abdullah Mahmoud YouTube: Petroleum Capsules
Email: PE.abdullah36@gmail.com FB: www.FB.com/abdullah.amar
8. Gas migration - how to deal with it
500 500
Well shut in - stabilised Bleed mud through choke,
allowing gas to expand, keeping
SIDPP at original value
600
Gas migrates - SIDPP increases
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Thanks for your interest
E.Abdullah Mahmoud YouTube: Petroleum Capsules
Email: PE.abdullah36@gmail.com FB: www.FB.com/abdullah.amar
Editor's Notes
A lighter fluid will naturally tend to float upwards (migrate) through a heavier (more dense) fluid. This is true of gas in a water based mud.
The rate at which this gas migrates appears to depend mainly on the type of mud and the angle of the hole.
A gas migrates, it will cause all the pressures in the wellbore to increase.
A gas migrates, it will cause all the pressures in the wellbore to increase.
A gas migrates, it will cause all the pressures in the wellbore to increase.
A gas migrates, it will cause all the pressures in the wellbore to increase.
A gas migrates, it will cause all the pressures in the wellbore to increase.
A gas migrates, remaining at constant pressure, all other pressures increase. To control this we must bleed mud off to allow the gas to expand.
But how much?
If the formation pressure was balanced initially by a SIDPP of 500 psi, which has now risen to 600 psi due to gas migration, then in theory we should bleed enough mud to take this SIDPP back to 500 psi.
In practice we would always leave ourselves a safety factor of 100 psi or so.
