Calculate Bottles Required for Koomey Unit (Accumulator Unit)

This topic will demonstrate you how to determine accumulator bottles required for Koomey Unit (Accumulator Unit) in order to close the surface BOP stack.

This is a specification of Accumulator (Koomey) Unit.

Accumulator 3,000 psi system

Volume each bottle is 10 gallon.

Pre charge pressure is 1,000 psi.

Minimum operating pressure is 1,200 psi (200 psi over pre charge pressure)

Usable fluid per gallon is 5 gallon.

Safety factor require is 50 %. This safety factor may be different depending on each company’s requirement.

BOP Stack and HCR’s as listed below:

 Equipment  Gallon to open  Gallon to close
 Annular Preventor  4.0  4.5
 Upper Pipe Rams  3.0  3.5
 Blind Shear Rams  3.5  4.0
 Lower Pipe Rams  3.0  3.5
 Choke HCR  0.5  0.5
 Kill HCR  0.5  0.5

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Well Control Kill Sheet Free Download

I got several people asking about well control kill sheets and Jeff Crawford share me the good kill sheets created by worldwide trusted well control company, Wild Well Control.


Their kill sheets are Excel files and they support several applications (surface stack, subsea stack, volumetric, lubricate and bleed, bullheading). There are several advantages from these well control kill sheets such as

• Solve problem either simple or complex wells

• Available for multiple casing, liner and tubular sizes

• Semi-automatically draw charts and graphs

• Calculate and display critical well control parameters

• Calculate how many bleed cycles required for volumetric well control

• Estimate maximum surface and pit gain for Volumetric

• Injection fluid vs pressure bleed down for Lube and Bleed

• Safety and working margins are established

It would be benefit you everybody to check out the well control sheets from Wild Well Control company.

Note: The new download links are updated in March 2017.

wild well control

Ultimate Killsheets  by Wild Well Control

Ps, Thanks for wild well control company ( for creating the good kill sheets. I wish these kill sheets would be advantage for your work. Have a nice day.

Drilling Formula Excel Sheet Version 1.2 Free Download

This is the second up date of drilling formula spread sheet, Drilling Formula Excel Sheet Version 1.2. 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 !!!.

Click here to get the drilling formulas spread sheet.

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.


Drill Pipe Pressure Schedule Calculation for Wait and Weight Well Control Method

This example demonstrates how to determine drill pipe pressure schedule for wait and weight method.


Well Information

Current mud weight = 9.5 ppg

Pump output = 0.1 bbl/stroke

Well depth = 9000’MD/9000’TVD

Drill string capacity = 0.0178 bbl/ft

Surface line volume = 15 bbl.

Shut in casing pressure = 700 psi

Shut in drill pipe pressure = 500 psi

ICP = 1600 psi at 30 spm as kill rate

Please follow steps below to determine the drill pipe pressure schedule (step down chart).

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Formulas for Wait and Weight Well Control Method

There are some well control formulas that you need to know for wait and weight method.


1. Kill Weight Mud

KWM = OMW + [SIDPP ÷ (0.052 x TVD)]


KWM is kill weight mud in ppg.

OMW is original mud weight in ppg.

SIDPP is shut in drill pipe pressure in psi.

TVD is true vertical depth of the well in ft.

Note: Read more about it>> Kill Weight Mud

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