Well Control Calculations

Kick Classification

• Kick while Drilling
• Kick after Pump Shutdown
• Swab Kick

Kill Methods

• Driller’s Method
• Wait and Weight Method (Engineer’s Method)
• Concurrent Method
• 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