Related topics

Beyond Well Control School

The KickDrill app covers the topics taught in the WellControl school. In addition, other topics are also covered but is not part of the exams. An example of this is Kick Tolerance where a case scenario is calculated through. The below shows a method that can be used to find how much gas you can take in without fracturing the weak spot in the well.

IADC & IWCF ALIGNED
“Precision in calculations is the first line of defense in pressure control.”

Example: We have the following input:
  • TVD TD 3800 m
  • TVD Shoe 2950 m
  • MW 1.50 sg
  • LOT@shoe 1.76 sg
  • Max Pore Pressure 1.65 sg
  • Kick density 0.22 sg
  • Cap BHA/OH 43.6 l/m
  • Cap DP/OH 63,4 l/m
  • Length of BHA 190 m
We for simplicity we assume a vertical well
Estimating Kick Intensity

Decide what is your maximum expected pore-pressure for the section (ie.. in ppg or g/cc) and subtract the mud-weight (expected to be) in use at that point. This is referred to as the “Kick intensity”. For added safety a safety factor can also be added to the estimated max expected PP. Using the input from above: We estimated max PP to be 1.65 sg and Mud Weight in use while entering the zone to be 1.50 sg: Intensity:

1.65 − 1.50 = 0.15 sg
Find MAASP

Find the MAASP using the Mudweight from above and the current LOT, expressed in pressure (Psi or BAR):

1.76 – 1.50 x 2950 x 0.0981= 75.3 Bar
Find max INFLUX Height

Find the Influx height by subtracting the Kick Intensity at TD expressed as pressure from the MAASP, and divide this with the MW minus the Gas Gradient, expressed in pressure per depth (eg. Bar/m). Note: Remember to use Vertical depth.

Height = Pit Gain / Annular Capacity
This is the maximum height of mudcolumn we can loose and replace with Gas with the assumptions made above.
Find Kick Volume 1 @ TD

Take the result from (3), and find how much volume this height of influx represents at TD. Remember to compensate for MD versus TD if the well is deviated (TVD=cosine to the well inclination x Measured depth).

At TD, the volume between the Open hole and BHA is 43.3 l/m in volume; since we have 190 m of BHA with this volume-displacement and the height found in (3) was 153.9 m, we can use the full length with this volume (not overshooting to also needing to use DP displacement). We assume a vertical well.

153.9m x 43.3 l/m= 6664 l

This is KICK VOLUME 1 @ TD.

Volume at shoe w maximum height:

Decide what is your maximum expected pore-pressure for the section (ie.. in ppg or g/cc) and subtract the mud-weight (expected to be) in use at that point. This is referred to as the “Kick intensity”. For added safety a safety factor can also be added to the estimated max expected PP. Using the input from above: We estimated max PP to be 1.65 sg and Mud Weight in use while entering the zone to be 1.50 sg: Intensity:

153.9m x 63.4 l/m= 9757 l
What was this volume when entering the well?

Decide what is your maximum expected pore-pressure for the section (ie.. in ppg or g/cc) and subtract the mud-weight (expected to be) in use at that point. This is referred to as the “Kick intensity”. For added safety a safety factor can also be added to the estimated max expected PP. Using the input from above: We estimated max PP to be 1.65 sg and Mud Weight in use while entering the zone to be 1.50 sg: Intensity:

1.76x2950x0.0981) (P1) x 9757 (V1) / (1.65x3800x0.0981) (P2) = 8079 l = V2

This 8079 liter of gas will increase to 9757 when at the shoe. However, the volume found in (4) 6664 liter will be the designing volume as this is the maximum volume we can have at TD without exceeding our maximum vertical column of gas in the well. If we had taken in a gascolumn of 8079 liter, it would have occupied more than 159 meter of vertical height when at TD and around the BHA.

Note: This assuming out input data is according to our estimates.

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