Stop Applying the Wrong Rule
A common well control mistake starts with a rule that is correct in the wrong situation.
During steady circulation, you may hold drillpipe pressure constant. That helps maintain the required bottomhole pressure while the pump runs at a stable speed.
But changing pump speed is not steady circulation.
Any time you move the pumps faster or slower while circulating a kick, hold casing pressure constant through the change.
That is the number you hold.
The drillpipe pressure will move. It is expected to move because friction changes with pump speed. The casing pressure is the direct reference during the rate change because the annular friction contribution is negligible for this control decision.
Miss this distinction, and you can apply a familiar rule at exactly the wrong moment.
Know Which Pressure Moves
Pump speed changes affect the pressure you see at the drillpipe.
Increase pump speed, and drillpipe pressure rises.
Decrease pump speed, and drillpipe pressure falls.
That movement does not automatically mean the well is becoming more or less controlled. It reflects the change in rate-dependent friction.
During the transition, casing pressure is the pressure you keep constant. Adjust the choke as needed to maintain that casing pressure while the pump speed changes.
The purpose is to maintain correct bottomhole pressure through the rate change.
The key relationship is simple:
- Pump speed changes.
- Friction changes.
- Drillpipe pressure responds.
- Casing pressure stays constant.
- Bottomhole pressure is maintained through the transition.
This is the point many learners miss when they memorize pressure rules without separating a rate change from stable circulation.
Why Bottomhole Pressure Matters
Bottomhole pressure is influenced by the pressure in the wellbore, including hydrostatic pressure, surface pressure, and circulating friction.
When the pump rate changes, the friction component changes too. That affects the pressure relationship in the system.
If you try to hold drillpipe pressure flat while the pump speed is changing, you are trying to keep constant a pressure that is expected to respond to friction. That can lead you away from the correct control reference.
Holding casing pressure constant gives you the direct surface reference needed during the rate transition.
The goal is not to make every gauge stay flat.
The goal is to maintain the correct pressure at the bottom of the well.
That difference matters. A pressure gauge may move because the system is responding normally. A flat reading may not always mean the correct pressure relationship is being maintained.
Use the correct gauge for the phase of the operation.
The Steady-Circulation Rule Has a Boundary
The steady-circulation rule is useful when the pump is already running at a stable rate.
At that point, the new drillpipe pressure becomes the working reference. Depending on the approved plan, you may:
- Hold the new drillpipe pressure constant during continued circulation
- Follow a stepdown chart as you weight up
Which method applies comes from the approved plan and the circulation method being followed.
Do not combine the two phases.
During the rate change:
Hold casing pressure constant.
After the rate is established:
Use the new drillpipe pressure or approved stepdown schedule as directed.
This boundary is the entire issue.
The mistake is not knowing that drillpipe pressure matters. The mistake is holding drillpipe pressure during the transition instead of recognizing that the number must move as pump speed changes.
Do Not Memorize a Choke Direction
Avoid reducing the rule to a phrase such as “pump up, choke out” or “pump down, choke in.”
That framing is not the rule for a pump speed change.
It only makes sense when casing pressure is the number being held and the required choke response is determined by the actual pressure trend, operating conditions, equipment, and approved procedure.
The reliable rule is more useful:
Change pump speed while holding casing pressure constant.
Do not memorize a choke movement without understanding which pressure must remain flat. A directional phrase can be misapplied, especially when conditions differ from the example used in training.
Focus first on the pressure target.
Then follow the approved procedure for maintaining it.
What Happens When the Rule Is Missed?
If drillpipe pressure is treated as the number to hold during a rate change, the casing pressure may move away from its required value.
That can change bottomhole pressure when the operation is intended to keep it controlled.
The consequences can include:
- Incorrect pressure control during the transition
- Unnecessary changes to surface pressure
- Confusion about whether the pressure response is normal
- Poorer interpretation of the kick response
- Loss of confidence in the working pressure reference
- A mismatch between the live operation and the approved plan
The issue is not simply that one gauge moves.
The issue is that the wrong pressure may be used to judge whether the well is being controlled.
This is why the casing pressure gauge deserves attention during the rate change. It is not background information. It is the number that confirms the pressure target is being maintained through the transition.
Build the Right Mental Model
Use this simple sequence when reviewing the concept:
Pump Speed Moves
The pump is moved faster or slower.
Drillpipe Pressure Responds
Drillpipe pressure rises with increased speed and falls with decreased speed because friction changes with rate.
Casing Pressure Stays Constant
The choke is adjusted as needed to keep casing pressure constant through the change.
The New Rate Becomes Stable
Once the new pump rate is established, the new drillpipe pressure becomes the working reference.
The Approved Plan Takes Over
Continue by holding drillpipe pressure constant or following the required stepdown chart as you weight up. Use the method specified in the approved plan.
This model gives you a clear separation between the transition and the circulation that follows.
It also supports stronger well control principles for drillers because you are connecting pressure behavior to the operating condition instead of relying on a single memorized phrase.
Connect It to Your Kill Sheet
A kill sheet is not just a collection of numbers. It is a plan for how pressure should behave during the operation.
That means every pressure reference needs to be understood in context.
When you review kill sheet calculation steps, ask:
- Is the pump rate changing or stable?
- Which pressure should remain constant at this stage?
- Which pressure is expected to move?
- What pressure becomes the working reference after the new rate is established?
- Does the approved plan call for constant drillpipe pressure or a stepdown schedule?
These questions help you avoid applying a steady-circulation rule to a changing-rate condition.
They also make your well control formulas and pressure calculations easier to interpret. The formula may be correct, but the operational reference can still be wrong if you apply it at the wrong time.
This is where focused well control calculations practice helps. Practice should not only test whether you can produce a number. It should help you recognize which number matters during each phase of the operation.
Continue the Learning Path
The previous post in this weekly series focused on how one bad pressure input can affect the entire kill-weight mud calculation. That same theme continues here.
Reliable well control depends on using the right input, the right reference, and the right rule for the situation.
A correct rule used at the wrong time can still create a poor decision.
Read more from the Well Control Blog and keep building your understanding one pressure relationship at a time.
For broader drilling well control training, use guided explanations and practice questions to test whether you can identify the correct pressure reference before you work through the calculation.
Get the Full Procedure
This post explains the control principle without replacing the approved operating procedure.
Do not use it as a standalone choke manipulation walkthrough. Follow your approved program, company procedures, and qualified instruction for field operations.
If you want to study the full topic, the paid Pro lesson Increase / Decrease Pumps While Circulating a Kick is available through the Well Control Coach study tools and subscription access.
The lesson is designed to help you connect the pressure behavior to the correct procedure, reinforce the decision points, and practice the concept in a structured learning environment.
Explore Well Control Coach subscription options and find the access level that fits your study needs.
Need more advanced support for calculations, kill sheet review, and deeper concept practice? The Pro membership includes expanded study support, image uploads, and kill sheet assistance.
Remember the Rule
When circulating a kick and changing pump speed:
- Hold casing pressure constant during the change.
- Expect drillpipe pressure to rise when pump speed increases.
- Expect drillpipe pressure to fall when pump speed decreases.
- Do not hold drillpipe pressure constant while the rate is changing.
- After the new rate is stable, follow the approved plan.
- Use the new drillpipe pressure or stepdown chart as directed.
Keep the phases separate.
Hold casing pressure through the rate change. Then use the approved working reference for continued circulation.
Log in, review the Pro lesson, and keep building confidence in the pressure decisions that matter.