I have a question asked regarding what the differences between True Vertical Depth (TVD) and Measured Depth (MD). Today, I will describe both definitions and their importance for calculation in a drilling field.
True Vertical Depth (TVD) is measured vertically from the surface down to a certain target down hole.
Measured Depth (MD) is the total length of the wellbore measured along the actual well path.
See the following illustration for more understanding.
If you would like to learn about drilling engineering, this book, Applied Drilling Engineering – Spe Textbook Series, is my recommendation. The book contains various topics regarding drilling engineering.
What will you learn from this book?
Rotary drilling – basic of drilling rigs, rig power system, hoisting system, circulating system, etc.
Drilling fluids – Mud test, pilot test, water based mud and oil based mud.
Cements – composition of cement, cement testing, cement additives, and cement placement techniques used in the drilling field.
Drilling hydraulics – Hydrostatic pressure, annular pressure during well control operation, buoyancy factor, non static well condition, flow through jet bits, rheology models, laminar and turbulent flow, surge/swab pressure and particle slip velocity.
I have posted several stuck pipe articles and I would like to summarize all articles in one page so you can use it for future reference.
Stuck pipe categories
There are 3 categories of stuck pipes as follows:
1. Packing off and bridging: There are seven cases in this category.
• Cutting settling in near well bore wells and cutting setting in deviated wells
• Junk
This is the second up date of drilling formula spread sheet, Drilling Formula Excel Sheet Version 1.2.
Drillingformulas.com distributed the first version of drilling formula spread sheet on 28 March 2011 and another update on 18 May 2011. The calculation sheet has been downloaded over 8,300 times around the world since the fist distribution.
Today, the lasted up date of drilling formula spread sheet, Drilling Formula Excel Sheet Version 1.2 is available for you to download. It is still totally FREE !!!.
What new drilling formulas are added into this version?
Cutting Slip Velocity Method#1
Cutting Slip Velocity Method#2
Surge and Swab Pressure Method#1
Surge and Swab Pressure Method#2
Hydrostatic Pressure Loss Due to Gas Cut Mud
Maximum pit gain from gas kick in water based mud
Maximum Surface Pressure from Gas Influx in Water Based Mud
How many total useful drilling formulas in this version?
There are a total of 75 formulas which are divided into 7 categories (Applied Drilling Formulas, Basic Drilling Formulas, Directional Drilling Calculation, Drilling Fluid Formulas, Engineering Formulas, Hydraulic Formulas and Well Control Formulas).
How much will it cost?
Nothing. The spread sheet is totally FREE for everybody.
This section will show to how to use the formula from the previous topic, surge and swab pressure calculation 2nd method , to determine surge and swab pressure. I still use the same parameters as I used for the first method of surge and swab pressure calculation so you can compare the result between method#1 and method#2.
The well information is listed below:
θ300 = 85
θ600 = 130
Hole diameter = 9 inch
Drill Collar = 6.25 inch
ID of drill collar = 2.5 inch
Drillpipe diameter = 5 inch
ID of drill pipe = 3.5 inch
Average pipe running or pulling speed = 250 ft/min
Drill Pipe Length = 12000 ft
Drill Collar Length = 800 ft
Current Mud Weight = 12.5 ppg
Well TVD = 9000 ft
