.Blowout Examples and Pictures
.Surface Well Control Equipment
.Phases of Well Control
.Well Control Operations
.Well Control during Routine Drilling
.Kick detection & Reaction to a kick
.Kick detection & Flow check
.Performing a flow check
.Shut in.Soft shut in
.Hard shut in.
- This technology focus on maintaining pressure on open formations (that is, exposed to the wellbore) to prevent or direct the flow of formation fluids into the wellbore.
-It encompasses the estimation of formation fluid pressures, the strength of the subsurface formations and the use of casing and muddensity to offset those pressures in a predictable fashion.
-Also included are operational procedures to safely stop a well from flowing should an influx of formation fluid occur.
-To conduct well-control procedures, large valves are installed at the top of the well to enable wellsite personnel to close the well if necessary.
Well control and Blowout Prevention:
Development oftechnology focused on maintaining pressure on open formations that are exposed to the wellbore, to prevent the uncontrolled flow of formation fluids into the wellbore.
A flow of formation of fluids into the wellbore during operations
Surface Blow out:
Uncontrolled flow of fluid into the wellbore and to surface
Underground Blow out:
Uncontrolled flow of a kick into other formationsShut in:
Closing the well with blowout preventer stack after a kick is detected.
Shut in Drill Pipe Pressure (SIDPP):
SIDPP is the pressure recorded at the stand pipe pressure gauge at the time of shut in after the pressures are stabilized
Shut in Casing Pressure (SICP):
SICP is the pressure recorded at the choke pressure gauge at the time of shut in after the pressures are stabilized.Pit gain:
Pit gain is the difference in pit volume before and after shut in. It is considered as the volume of kick fluid in the well.
If a casing string or a drillstring is lowered into the well, the pressure at a given point in the well increases. A pressure increase due to downward pipe movement is called a surge pressure.
To reduce pressure in wellboreby moving pipe, wireline tools or rubber-cupped seals up the wellbore. If casing string or drillstring is pulled from the well, the pressure at given point in the well decreases. If the pressure is reduced sufficiently, reservoir fluids may flow into the wellbore. Swabbing is generally considered harmful in drilling operations, because it can lead to kick and wellbore stability problems.
Leakoff test (LOT):
Leak off test is a pressure test for determining the leak off pressure (Fracture pressure) of open hole. The objectives of LOT are:
.To determines maximum safe pressure to impose on casing shoe.
.To determines or verifies formation fracture pressure.
.To determines whether the cement job is adequate.
Leak of test are therefore typically used to evaluate both formationstrength, specifically fracture pressure, and cement integrity.
Definitions - Abnormal Pressure
Causes of abnormal pressure
.Compaction effects - Rapid sediment deposition restricts pore fluids from draining during burial
.Diagenetic effects - Rock chemistry changes with time, temperature, pressure and can create a pressure seal or cap
.Differential density effects - e.g. gascolumn
.Fluid migration effects - natural or man-made (injection of water or gas to maintain reservoir pressure)
Detection of Abnormal Pressure Zones
Detection of zone with higher pressure than the wellbore pressure
.Rate of penetration
.Shale Density Change
.Shale Cutting Size and Shape
.Change in Mud Chlorides
.Increase in any measure of gas in mud