Primary Well Controlis the hydrostatic pressure in the wellbore thatprevents reservoir influx while performing drilling.

When primary well control is failed, then, this situation needs specialequipment which is called Blow Out Preventer or BOPto control kick.

We can call thatBlow Out Preventer or BOP is Secondary Well Control.Please also remember that BOP must be used with specific procedures tocontrol kick such as Driller's, Wait and weight, Concurrent, Volumetric,Lubricate & bleed and Bull heading methods.

Without well control practices for using BOPs,it will just be only heavy equipment on the rig.There are several types of Blow Out Preventer (BOP)which have different applications.

Well control training is the training required to prevent situations where lossof control of a primary and/or secondary well barrier will result in blow-out orother catastrophic events. Well control training therefore covers all aspects ofwell engineering and operations from well designers, through thedrilling crew, well service crew and service personnel.

Why do we lose Primary Control? Main reason is human error

1. Failure to follow procedures2. Lack of knowledge3. Lack of skills4. Failure to communicateWhy do we lose Secondary Control? Main reasons are equipment failureand humanerror

1. Failure to follow procedures2. Lack of knowledge3. Lack of skills