Category Archives: Drilling Fluid Calculations

Starting volume of original mud (weight up with Hematite)

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You know how much volume will be increased due to adding  Hematite into the system; however, you sometimes are limited to total volume due to limit pit volume on the rig so you need to calculate starting volume to achieve the predetermined final volume of desired mud weight. This formula below is used to determine the staring volume of mud with Hematite.

Starting volume in bbl = VF x (40 – W2) ÷ (40 – W1)

Where; W1 = current mud weight in ppg

W2 = new mud weight in ppg

VF = final volume in bbl

Example: Determine the barrel of starting volume of 10.0 ppg (W1) mud required to achieve 100 bbl (VF) of 13.0 ppg (W2) mud with Hematite:

 

Starting volume in bbl = VF x (40 – W2) ÷ (40 – W1)

Starting volume in bbl = 100 x (40 -13.0) ÷ (40 – 10.0)

Starting volume = 90 bbl

In order to achieve 100 bbl of 13.0 ppg mud weight up with Hematite, you must have 90.0 bbl starting volume of 10.0 ppg mud.

Please find the Excel Sheet for calculating starting volume of original mud weight up with Hematite.

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

Volume of Mud Increases due to Adding Hematite

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The concept of mud volume increase due to adding Hematite is as same as the mud volume increase by adding barite and calcium carbonate. The formula for calculating volume increment is just different only one factor which is 40 for hematite but 22.5 is usedfor calcium carbonate and 35 is used for barite. Please follow the formula below for determining volume increase because of adding Hematite.

Volume increase per 100 bbl of mud = 100 x (W2 – W1) ÷ (40 – W2)

Where; W1 = current mud weight

W2 = new mud weight

Please read and follow the example below for more understanding.

Example: Determine the volume increase when increasing the density with hematite from 10.0 ppg (W1) to 13.0 ppg (W2):

Volume increase per 100 bbl of mud =100 x (13.0 – 10.0) ÷ (40 – 13.0)

Volume increase per 100 bbl of mud = 11.11 bbl

If you have total volume of 500 bbl of mud, the volume increase due to adding calcium carbonate will be equal to 55.56 bbl (11.11 x 500 ÷ 100).

Please find the Excel sheet used to calculate how much volume increased due to adding Hematite.

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

Increase Mud Weight by Adding Hematite

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You have learn how to weight up with Barite andCalcium Carbonate from previous posts. Sometimes, you may need to weight up to extremely high weight therefore you may consider using Hematite , its average specific gravity +/- 4.8, to weight up your mud system. If you are interested in Hematite information, please take a look at Wiki.

The concept of weighting up calculation with Hematite is as same as the concept of weighting up with Barite and Calcium Carbonate. The only one thing change is weight factor used in the equation. Please follow the equation below for calculating how many sacks required to weight up per 100 bbl of original mud.
Sacks of Hematite per 100 bbl of mud = 1680 x (W2 – W1) ÷ (40 – W2)

Where; W1 = current mud weight in ppg

W2 = new mud weight in ppg

Example: Determine the number of sacks of Hematite per l00 bbl required to increase the density from 10.0 ppg (W1) to 13.0 ppg (W2):

Sacks of hematite per 100 bbl of mud = 1680 x (13.0 – 10.0) ÷ (40 – 13.0)

Sacks of hematite per 100 bbl of mud = 186.7 sacks

If you have total volume of 500 bbl of mud, hematite required to increase mud weight from 10.0 ppg to 13.0 ppg is 933.3 sacks (186.7×500/100).

Please find the Excel used for calculating how many sacks required in case of weighting up with Hematite.

 

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

Starting volume of original mud (weight up with Calcium Carbonate)

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You know how much volume will be increased due to adding calcium carbonate into the system; however, you sometimes are limited to total volume due to limit pit volume on the rig so you need to calculate starting volume to achieve the predetermined final volume of desired mud weight.
This formula below is used to determine the staring volume of mud (for calcium carbonate system).

Starting volume in bbl  = VF x (22.5 – W2) ÷ (22.5 – W1)

Note: 22.5 is density of calcium carbonate in ppg.

Where; W1 = current mud weight in ppg

W2 = new mud weight in ppg

VF = final volume of mud needed in bbl

Example: Determine the barrel of starting volume of 10.0 ppg (W1) mud required to achieve final volume of 100 bbl (VF) of 13.0 ppg (W2) mud with calcium carbonate:

Starting volume in bbl = VF x (22.5 – W2) ÷ (22.5 – W1)

Starting volume in bbl = 100 x (22.5 – 13.0) ÷ (22.5 – 10.0)

Starting volume = 76 bbl

In order to achieve  final mud volume of 100 bbl of 13.0 ppg mud weight up with calcium carbonate, you must have 76.0 bbl starting volume of 10.0 ppg mud.


Please find the Excel sheet for calculating Barrel of starting volume of original mud weight required to give a predetermined final volume of desired mud weight with CALCIUM CARBONATE.

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

Volume of Mud Increases due to Adding Calcium Carbonate

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The concept of mud volume increase due to adding calcium carbonate is as same as the mud volume increase by adding barite. The formula for calculating volume increment is just different only one factor which is 22.5 for calcium carbonate but 35 is used for barite case. Please follow the formula below for determining volume increase because of adding calcium carbonate.

Volume increase per 100 bbl of mud due to adding Calcium Carbonate = 100 x (W2 – W1) ÷ (22.5 – W2)

Where; W1 = current mud weight in ppg

W2 = new mud weight in ppg

Example: Determine the volume increase when increasing the density with calcium carbonate from 10.0 ppg (W1) to 13.0 ppg (W2):

Volume increase per 100 bbl of mud =100 x (13.0 – 10.0) ÷ (22.5 – 13.0)

Volume increase per 100 bbl of mud = 31.58 bbl

If you have total volume of 500 bbl of mud, the volume increase due to adding calcium carbonate will be equal to 157.9 bbl (31.58 x 500 ÷ 100).

Please find the Excel sheet for determine mud volume increase due to adding calcium carbonate.

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