Trip margin is an increment of drilling mud density to provide overbalance so as to compensate the swabbing effect while pulling out of hole.
You can quickly calculate how much trip margin required by this following simple equation.
Trip Margin = Mud Yield Point ÷ [11.7 x (Hole diameter – Drill pipe diameter)]
The unit of each parameter is as follows;
Trip Margin in ppg (pound per gallon)
Mud Yield Point in lb/100 sq ft
Hole diameter in inch
Drill pipe diameter in inch
Let’s try to determine the trip margin with the following information.
Mud Yield Point = 12 lb/100 sq ft
Hole diameter = 10 inch
Drill pipe diameter = 5 inch
Trip Margin = 12 ÷ [11.7 x (10 – 5)] = 0.2 ppg
Please find the Excel sheet to calculate Trip Margin – -> 
Trip Margin Calculation Sheet
Ref book: Formulas and Calculations for Drilling, Production and Workover, Second Edition
it is good but we need law to provide how much i can increase mud weight without reach to M A A S P
Hi Ramadan,
You need know your ECD and your LOT. The LOT will limit how much mud weight you can use in the well.
Regards,
Shyne
i did not recieve any post last month any new news i am used t get the new post day after day
abualham@aramco.com
I added you into the system.
Hello,
I have a question about trip margin. Is trip margin calculation necessary when TOOH ? A lot of companies standard procedure is to have 200-300 psi (0.5-0.8 ppg) of overbalance pressure (over the formation pressure) at all time. This means if 10 ppg mud is sufficient to control the formation pressure, 10+0.5= 10.5 or 10.8 ppg mud is used to drill over balance.
My question is this:
Is it still necessary to calculate the trip margin when TOOH if the hole is getting filled regularly ( every 75 psi of pressure drop) ?? So, even with mud weight that already considers overbalance pressure, do we still have to calculate “trip margin” and add it to the designed mud weight?
You need to know how much over balance of you mud weight is before POOH. If the overbalance is more than trip margin, it should be OK for pulling out. However, if you are so close to pore pressure, it is recommended to add more weight for a trip margin.
trip margin equal
= overbalance/0.052/TVD + mud weight