Primary kick indicators

Kick is the influx of formation fluid into the borehole.It can be gas, oil, water or mixture of them.Kick can be detected by several drilling and mud parameters. Some are more sure and are called primary indicators, while some are less sure and can be due to other reasons and are called secondary indicators

Primary Kick indicators

  • Increase in mud flowout-Mud flowout values are always recorded in percentage . Its value is of less importance but the changes in its value are important. Decrease in its value shows losses (provided the pump flow rate is constant) while increase in its value shows gain or influx (kick).
  • Pit volume increase- Generally while drilling pit volume should decrease gradually (this volume will be required to fill the extra hole drilled).In case of kick, extra fluid have entered the hole and will be seen as increase in pit volume at surface.
  • Flowing hole with pumps shut off:- Mud pumps are required to circulate the mud into and out of the hole.When the pumps are shut off mud should also stop flowing and there should be no mud flow observed at the flow line.But in case of kick, even after shutting off the pumps mud will flow and it can be seen in the return line.
  • Improper hole fill up while tripping- It is a common practice to keep the hole full, whatever the operation may be, to avoid underbalance condition.While tripping out mud level in the hole should decrease due to pipe displacement, this pipe displacement should be calculated and same volume of mud should be required to keep the hole full. If less mud is required to keep the hole full it means formation fluid has entered into the hole.
    For e.g:-
    Operation- POOH (Pull out of hole) 3 1/2" drillpipe
               Calculated Displacement of 1 stand = 0.5 bbl
               Calculated Displacement of 5 stands=5×0.5=2.5 bbl
    So after pulling out 5 stands of 3 1/2" drillpipe we need to fill 2.5 barrels of mud into the hole.But if less than 2.5 barrel of mud is enough to keep the hole full that means some extra fluid has entered into the hole and the kick has taken place.

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