Drilling Formulas and Drilling Calculations

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 weigth 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 drill, production and workover by Norton J. Lapeyrouse

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 drill, production and workover by Norton J. Lapeyrouse

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You have learn how to weight up with Barite and Calcium 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, calcium carbonate 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 drill, production and workover by Norton J. Lapeyrouse

Note: If you don’t want to miss any post from drillingformulas.com, please consider subscribing to our mail list. So you will not miss our posts.

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)

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.

Ref book: Formulas and Calculations for drill, production and workover by Norton J. Lapeyrouse

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.

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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

W2 = new mud weight

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 drill, production and workover by Norton J. Lapeyrouse

Note: If you don’t want to miss any post from drillingformulas.com, please consider subscribing to our mail list. So you will not miss our posts.

Carbonate is weighing agent mostly used in horizontal well because it does not plug up formation. We can use the same weight up concept with barite to calculate how to weight up with carbonate. Follow a topic below to learn how to weight up with calcium carbonate.

NOTE: The maximum practical mud weight attainable with calcium carbonate is 14.0 ppg.

This formula below is used for calculating how many sacks of calcium carbonate required per 100 bbl of drilling fluid (Mud weight increase with calcium carbonate (SG – 2.7))

Sacks of calcium carbonate per 100 bbl of mud = 945 x (W2 – W1) ÷ (22.5 – W2)

Where; W1 = current mud weight

W2 = new mud weight

Example: Determine the number of sacks of calcium carbonate per l00 bbl required to increase the density from 10.0 ppg (W1) to 13.0 ppg (W2):
Sacks of calcium carbonate per 100 bbl of mud = 945 x(13.0 – 10.0) ÷ (22.5 – 13.0)

Sacks of calcium carbonate per 100 bbl of mud = 298.4 sacks
If you have total volume of 500 bbl of mud, calcium carbonate required to increase mud weight from 10.0 ppg to 13.0 ppg is 1,492 sacks (298.4×500/100).

Please find the Excel sheet for calculating how many sacks of calcium carbonate required per 100 bbl of drilling fluid.

Ref book: Formulas and Calculations for drill, production and workover by Norton J. Lapeyrouse

Note: If you don’t want to miss any post from drillingformulas.com, please consider subscribing to our mail list. So you will not miss our posts.

You know how much volume will be increased due to adding barite 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 star volume of mud in case of weighting up with Barite.

Starting volume in bbl = VF x (35 – W2) ÷ (35 – W1)

Where; W1 = current mud weigth in ppg

W2 = new mud weight in ppg

VF = final volume in bbl

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

Starting volume in bbl = 100 x (35 – 13.0) ÷ (35 – 10.0)

Starting volume in bbl= 88.0 bbl

In order to achieve 100 bbl of 13.0 ppg mud weight up with barite, you must have 88.0 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 barite.

Ref book: Formulas and Calculations for drill, production and workover by Norton J. Lapeyrouse

Note: If you don’t want to miss any post from drillingformulas.com, please consider subscribing to our mail list. So you will not miss our posts.

After adding barite to increase mud weight in the system, total mud volume will increase due to volume of dry barite. This formula below shows you how to determine volume of mud increase in bbl per 100 bbl of original mud.

Volume increase per 100 bbl of mud = 100 x (W2 – W1) ÷ (35 – W2)

Where;

W1 = current mud weight
W2 = new mud weight

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

Volume increase per 100 bbl of mud = 100 x (13.0 – 10.0) ÷ (35 – 13.0)
Volume increase per 100 bbl of mud = 13.64 bbl

If you have total volume of 500 bbl of mud, the volume increase due to adding barite will be equal to 68.2 bbl (13.64 x 500 ÷ 100).

Please find the Excel sheet for calculating volume of mud in bbl increase due to adding Barite.

Ref book: Formulas and Calculations for drill, production and workover by Norton J. Lapeyrouse

Note: If you don’t want to miss any post from drillingformulas.com, please consider subscribing to our mail list. So you will not miss our posts.

Weight up is the critical operation while drilling so we need to know how to weight up with weighting agent such as barite, calcium carbonate, hematite, etc. I have separate about mud calculation into several sub topic so you can follow each topic easily. This time I will demonstrate how to calculate how many sacks of barite needed to increase mud weight in ppg with barite. (average specific gravity of barite – 4.2)

The formula for weight up with barite is listed below:
Sacks of Barite per 100 bbl of mud = 1470 x (W2 – W1) ÷ (35 – W2)

Where; W1 = current mud weight

W2 = new mud weight

Example: Determine the number of sacks of barite required to increase the density of

100 bbl of 10.0 ppg (W1) mud to 13.0 ppg (W2):

Sacks of Barite per 100 bbl of mud = 1470 x (13.0 – 10.0) ÷ (35 – 13.0)

Sacks of Barite per 100 bbl of mud = 200.5 sacks
If you have total volume of 500 bbl of mud, the barite required to increase mud weight from 10.0 ppg to 13.0 ppg is 1,002.5 sacks (200.5×500/100).

Please find the Excel sheet used for weighting up with barite.

Ref book: Formulas and Calculations for drill, production and workover by Norton J. Lapeyrouse

Note: If you don’t want to miss any post from drillingformulas.com, please consider subscribing to our mail list. So you will not miss our posts.