Causes & Warnings of a Kick in the Wellbore

Even on a strictly monitored oil drill site, there’s always the potential for something to go wrong. Most people think about safety procedures in the event of a blowout. However, as with many disasters, it’s possible to stop a blowout before it becomes uncontrollable. You can prevent blowouts from happening by monitoring your oil wells for signs of the first stage of a blowout: a kick.

A kick occurs in an oil well when the pressure exerted by the rock surrounding the bore is stronger than the pressure in the wellbore itself. This eventually results in fluid rushing into the wellbore to attempt to stabilize the pressure. This influx of fluid is called a kick, and unless properly controlled, this can lead to a blowout. Let’s take a closer look at a few common causes of oil well kicks and how to prevent them from resulting in disaster.

It’s possible to catch a blowout before it starts by watching for signs of a kick in the wellbore. Learn what a kick is, what causes it, and how to control it here. #BOPproducts #oilfieldsafety #drilling #oilfield Click To Tweet

What Causes a Kick in the Wellbore?

As stated earlier, a kick is the result of unbalanced pressure in the wellbore. The pressure of the mud column may be less than the formation pore pressure, or gas entering the wellbore can exert high pressure on the mud column. Drilling fluid flowing too quickly can also spread into surrounding formations and compress the mud column beyond safe levels.

Kicks can also be caused by a mistake on the operator’s part during certain procedures. For example, when a pipe is being removed from the wellbore, there must be enough mud pumped into the wellbore to replace the pipe. This ensures that the wellbore is still supported against the pressure exerted by the surrounding rock. However, if not enough mud is pumped in or it enters the well too slowly, removing the pipe results in suction in the wellbore. This can definitely cause a kick.

Warning Signs of a Kick

Any oilfield operator knows the importance of balancing the amount of fluid in the wellbore at all times. If the amount of fluid suddenly increases for no apparent reason, that’s a sign that something is very wrong and a kick is occurring. Examples of this scenario could include:

  • Drilling fluid return rates increase while the pumps continue operating at their normal speed
  • Drilling fluid continues returning even when the pumps are turned off
  • Drilling fluid stops flowing into the wellbore, but mud levels in the well continue to climb
  • The pipe is removed from the wellbore, but the amount of mud present in the well increases in volume to exceed the volume of the pipe.
  • The pump stroke increases while the pump pressure decreases
  • The density of the mud in the well decreases as additional fluid flows in
  • The weight-on-bit indicator shows levels not consistent with the visible drilling conditions
  • The drill suddenly moves much faster than before or drops to a surprising depth, indicating a pocket of fluid or gas that could lead to a kick

To summarize, any unexpected change in pressure or fluid present in the wellbore is a strong indicator of a kick.

Pro Tip: If you can learn to recognize the signs of a kick in the oil well, you’ll be able to take action in time to prevent a blowout. Make sure you know the warning signs!

How to Keep a Kick Under Control

No one-size-fits-all method for containing a kick exists. Since each oil well uses slightly different equipment and may be drilling through different types of stone, every drill site has to modify the standard procedure for their own needs. However, every plan should contain a few standard steps that most locations can comply with:

  • Stop drilling and/or rotating the drill pipe
  • Raise the drill bit from the rig floor
  • Deactivate the mud pumps and monitor mud levels for unexpected rises
  • If mud continues to enter the wellbore, close the annular BOP

From there, the next steps depend on your well site’s capabilities. It’s best to become familiar with the equipment you have on hand to contain a kick. Make your plans ahead of time.

Keep Blowouts from Happening

Learning to recognize the warning signs of a kick is an invaluable skill in the oil and gas industry. By catching a problem in its early stages, you can prevent a blowout from occurring and prevent catastrophic damage to your surroundings.

Connect with us to see how our BOPs can help you manage kicks in your oilfield.