CAUSES OF KICKS
PRIMARY CONTROL
NORMALLY:
MUD HYDROSTATIC = FORMATION PRESSURE
WHAT CAUSES MUD HYDROSTATIC TO DROP?
PRESSURE = 0.052 X MUD WT X TVD
HOW CAN HYDROSTATIC PRESSURE CHANGE?
CAUSES OF KICKS (REDUCTION IN MUD WEIGHT)
RUNNING INTO A BUBBLE
CIRCULATING HOLE CLEAN
ADDITIONAL CAUSES OF KICKS (SUBSEA)
Accidental Riser Disconnect (Riser Margin)
- Riser can be accidentally disconnected due to vessel drive off’s, hydraulic control problem, riser failure, etc.
- Bottomhole pressure will be reduced due to net loss of hydrostatic pressure.
- In this example, BHP would be reduced by:
Mud Loss = 1770 x 10.8 x .052 = 994 psi
Seawater HP = 1710 x 0.445 psi/ft = 761 psi
Net Loss = 994 – 761 = 233 psi
GAS IN THE WELLBORE
Effect Of Gas Expansion in Open Well
Gas in Subsea Riser
