Category Archives: Applied Drilling Calculations

Maximum surface pressure from kick tolerance factor

By | | , ,
1 Comment

You have learned about the kick tolerance factor from the previous blog posting and this article will demonstrate you how to use the kick tolerance factor to determine the maximum surface pressure from it.

The formula is listed below;

Maximum surface pressure = kick tolerance factor x 0.052 x TVD of well

Where;

Maximum surface pressure in psi

kick tolerance factor in ppg

TVD of well in ft

Determine the maximum surface pressure with this following data:

Kick tolerance factor = 1.8 ppg

Hole depth = 10,000’MD/9500’TVD

Based on these data, you can calculate the maximum surface pressure like this;

Maximum surface pressure = 1.8 x 0.052 x 9500 = 889 psi

Please find the Excel sheet for this calculation Maximum surface pressure from kick tolerance factor

Ref book: Formulas and Calculations for Drilling, Production and Workover, Second Edition

Kick Tolerance Factor Calculation

By | | , , ,
3 Comments

The following formula is the kick tolerance factor.

Kick Tolerance Factor Formula
Where;

Casing shoe TVD in ft

Well depth TVD in ft

Maximum Allowable MW in ppg

Current MW in ppg

For more understanding, let’s try to calculate the kick tolerance factor (KTF) using the following information:

Continue reading →

Maximum Initial Shut-In Casing Pressure (MISICP)

By | | , ,
7 Comments

Maximum Initial Shut-In Casing Pressure (MISICP) or Maximum allowable shut in casing pressure is the initial shut-in casing pressure that will exceed formation strength at the casing shoe resulting in broken formation at the shoe.

How can we know and calculate the MISICP?

Leak Off Test (LOT) will tell you the maximum pressure which the shoe can withstand before breaking formation at the shoe. The LOT is the combination of surface pressure and hydrostatic pressure therefore you can apply this principle to calculate the MISICP.

Continue reading →

What are the differences between Formation Integrity Test (FIT) and Leak Off Test (LOT).?

By | | , , ,
15 Comments

You may confuse between Formation Integrity Test (FIT) and Leak Off Test (LOT).

They are different in this following aspect.

Leak Off Test – you pressure test shoe and formation until formation break down.

Let’s I explain more about it: Leak off Test is conducted in order to find the fracture pressure (fracture gradient) of formation and shoe. When conducting the LOT, you will pump drilling fluid to until you see the fracture trend of formation. Once formation is fractured, the first pressure that deviated from a trend is typically called Leak Off Pressure. We use the leak off pressure to calculate LOT.

Continue reading →

Drilling Formulas and Calculation Summary Page

By | | , , , , , , , ,
17 Comments

I created summary page for drilling formulas and calculations (https://www.drillingformulas.com/drilling-formulas-and-calculation-sheets/). I wish these excel sheets would be helpful for you.

Amount of cuttings produced per foot of hole drilled
Annular Pressure Loss
Annular-Capacity
Annular-velocity
Bulk Density Calculation
Buoyancy Factor Oilfield
Convert Pressure to Equivalent Mud Weight
Convert-Specific-Gravity
Cost Per Foot Calculation
Critical RPM
D Exponent Calculation
D Exponent Corrected Calculation
Decrease Oil Water Ratio
Density of Oil Water Mixture
Depth of Washout
Continue reading →