WELLCONTROL CALCULATIONS

Kick Classification

Kick while Drilling

Kick after Pump Shutdown

Swab Kick 

KILL METHODS

  • Driller’s Method

Two circulations:

Kick is circulated out using original mud weight

Kill mud is circulated

  • Wait and Weight Method (Engineer’s Method)

Once circulation:

Kill mud is circulated to circulate out the kick

  • Concurrent Method

Original mud is weighted incrementally in stages to the kill mud weight while the kick is circulated out.

  • Volumetric Method
  • Bullheading Method

Kill Mud Weight

Formation Pressure (psi) = 0.052 x original mud weight, ppg x vertical depth, ft + shut-in drillpipe pressure, psi

Kill mud weight (ppg) = original mud weight, ppg + (shut-in drillpipe pressure, psi /0.052 x vertical depth, ft) + overkill safety margin, ppg

 Initial Circulating Pressure

Initial Circulating Pressure (ICP) = shut-in drillpipe pressure, psi + slow circulating pump pressure, psi + overkill pressure, psi

 Final Circulating Pressure

Final Circulating Pressure (FCP) = slow circulating pump pressure, psi x (Kill mud weight (ppg)/ overkill safety margin, ppg) 

Length and Density of Kick

Length of the kick, ft = pit gain, bbl /( annulus capacity behind drillcollar, bbl/ft)

For pit gain, bbl < annulus volume against drillcollar, bbl

Length of the kick, ft = length of the drillcollar, ft + (pit gain, bbl – annulus volume against drillcollar, bbl)/ annulus capacity behind drillpipe, bbl/ft

For pit gain, bbl > annulus volume against drillcollar, bbl

Density of Kick

Density of the Kick, ppg = initial mud weight, ppg – (initial stabilized drillpipe pressure, psi – initial stabilized casing pressure, psi)/(0.052 x Length of the kick, ft)

Riser Margin

Riser margin is = (drilling fluid gradient to control the formation pressure with riser, psi/ft  x depth of the hole (TVD), ft  – seawater gradient, psi/ft

seawater gradient, psi/ft x water depth, ft )/ (depth of the hole (TVD), ft – water depth, ft

  • air gap, ft)Type of KickOil and gas mixture 0.25 < density of kick < 0.3 psi/ftWater Kick 0.4 < density of kick psi/ft
  • Oil or condensate 0.3 < density of kick < 0.4psi/ft
  • Gas Kick < 0.25 psi/ft