Category Archives: Basic Drilling Formulas

Drilling Formula Excel Sheet Version 1.2 Free Download

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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

Total Flow Area Table

Calculate Influx Height

Hydrostatic Pressure Loss Due to Gas Cut Mud

Kill Weight 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.

 

Water Kick and Oil Kick Indications

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All of well control articles in this website are based on gas kick assumption. Therefore, all the responses as bottom hole pressure, surface pressure, gas volume, maximum pit gain, etc are influenced by gas expansion and gas migration. In reality, you may face with water influx or oil influx which is quite different than gas influx.

 water-kick-oil-kick

The following indications showing water or oil kick are listed below:

• When the well is shut in, casing pressure will not increase because water and oil don’t migrate.

• When bumping the float, it is quite clear to see where the float is opened in order to obtain shut in drill pipe pressure.

• While circulating influx out of the wellbore, casing pressure will not increase too high because water and oil don’t expand like gas.

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Advantages and Disadvantages of Wait and Weight Method

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We’ve learned so many topics regarding wait and weight well control method and I would like to share what advantages and disadvantages of wait and weight method are.

 

Advantages of Wait and Weight Method

• When compared to driller’s method, the wait and weight will generate lower pressure at casing shoe while circulating.

• It will generate the lowest pressure on surface equipment.

• It requires less circulation than driller’s method therefore time of equipment exposed to pressure is less.

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Determine surge and swab pressure for close-ended pipe

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I would like to show more calculation about surge and swab pressure. In this article, I will show how to use the previous formulas (Surge and swab pressure method 1) to figure out surge and swab pressure for close-ended pipe (plug flow). The calculation concept is pretty much the same but I would like to show you how much difference between surge/swab if you have the close-ended pipe.

 

I still use the same data but this time so I can compare apple to apple with the previous calculation.

 

Example

 

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

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Hydraulicing Casing (pressure to lift the casing while cementing)

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During cementing operation, pumping cement and displacement fluid can lift the casing. Some people call “pump out of the well”. This situation can be occurred and there are some reasons as follows:

• Lightweight casing string

• Large casing diameter

• High density of cement

• Low density of displacement fluid

• High annular pressure loss

• High pressure trapped in the annulus due to bridging

How is the casing lifted during cementing?


Under A Static Condition

The casing can be hydraulic out of hole due to unbalance of hydrostatic pressure. See the figure below for more understanding.

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