Water requirements

a) Weight of materials, lb/sk:

Weight, lb/sk = 94 + (8.33 x vol of water, gal) + (% of additive x 94)

b) Volume of slurry, gal/sk:

94 lb/sk wt of additive, lb/sk

c) Water requirement using material balance equation: D,V, = D2V2

Example: Class H cement plus 6% bentonite to be mixed at 14.01b/gal. Specific gravity of bentonite = 2.65.

Determine the following:

Bentonite requirement, lb/sk Water requirement, gal/sk Slurry yield, ft3/sk Check slurry weight, lb/gal

1) Weight of materials, lb/sk:

Weight, lb/sk = 94 + (0.06 x 94) + (8.33 x "y") Weight, lb/sk = 94 + 5.64 + 8.33"y" Weight = 99.64 + 8.33"y"

2) Volume of slurry, gal/sk:

94 5 64

Vol, gal/sk = 3.86 + "y"

  1. Water requirement using material balance equation:
  2. 64 + 8.33"y" = (3.86 + "y") x 14.0 99.64 + 8.33"y" = 54.04 + 14.0"y" 99.64 - 54.04 = 14.0"y" - 8.33"y" 45.6 = 5.67"y" 45.6 - 5.67 = "y"
  3. 0 = "y" Thus, water requirement = 8.0gal/sk of cement
  4. Slurry yield, ft3/sk: 3.6 + 0.26 + 8.0

7.48

11.86

7.48

Yield = 1.59ft3/sk

5) Check slurry density, lb/gal:

Density, lb/gal = Density, lb/gal

11.86

166.28

11.86

Density = 14.01b/gal Field cement additive calculations

When bentonite is to be pre-hydrated, the amount of bentonite added is calculated based on the total amount of mixing water used.

Cement program: 240sk cement; slurry density = 13.8ppg;

  1. 6gal/sk mixing water; 1.5% bentonite to be pre-hydrated:
  2. Volume of mixing water, gal:

Volume = 240 sk x 8.6gal/sk Volume = 2064 gal b) Total weight, lb, of mixing water:

Weight = 2064gal x 8.33 lb/gal Weight = 17,1931b c) Bentonite requirement, lb:

Bentonite = 17,1931b x 0.015% Bentonite = 257.891b

Other additives are calculated based on the weight of the cement: Cement program: 240sk cement; 0.5% Halad; 0.40% CFR-2:

a) Weight of cement:

Weight = 240 sk x 941b/sk Weight = 22,5601b b) Halad = 0.5%

Halad = 22,5601b x 0.005 Halad = 112.81b c) CFR-2 = 0.40%

Table 2-1

Water Requirements and Specific Gravity of Common Cement Additives

Material

Water Requirement gal/94 lb/sk

Specific Gravity

API Class Cement Class A & B Class C Class D & E Class G Class H

  1. 3 4.3 5.0
  2. 3-5.2 6.3
  3. 14 3.14 3.14 3.14 3.14 3.14

Chem Comp Cement

Table 2-1 (continued)

Water Requirement Specific

Material gal/94 lb/sk Gravity

Water Requirement Specific

Material gal/94 lb/sk Gravity

Table 2-1 (continued)

Attapulgite

1.3/2% in cement

2.89

Cement Fondu

4.5

3.23

Lumnite Cement

4.5

3.20

Trinity Lite-weight Cement

9.7

2.80

Bentonite

1.3/2% in cement

2.65

Calcium Carbonate Powder

0

1.96

Calcium Chloride

0

1.96

Cal-Seal (Gypsum Cement)

4.5

2.70

CFR-1

0

1.63

CFR-2

0

1.30

D-Air-1

0

1.35

D-Air-2

0

1.005

Diacel A

0

2.62

Diacel D

3.3-7.4/10% in cement

2.10

Diacel LWL

0 (up to 0.7%)

1.36

0.8:1/1% in cement

Gilsonite

2/50-lb/ft3

1.07

Halad-9

0 (up to 5%) 0.4-0.5

1.22

over 5%

Halad 14

0

1.31

HR-4

0

1.56

HR-5

0

1.41

HR-7

0

1.30

HR-12

0

1.22

HR-15

0

1.57

Hydrated Lime

14.4

2.20

Hydromite

2.82

2.15

Iron Carbonate

0

3.70

LA-2 Latex

0.8

1.10

NF-D

0

1.30

Perlite regular

4/8 lb/ft3

2.20

Perlite 6

6/38 lb/ft3

-

Pozmix A

4.6-5.0

2.46

Salt (NaCl)

0

2.17

Sand Ottawa

0

2.63

Silica flour

1.6/35% in cement

2.63

Coarse silica

0

2.63

Spacer sperse

0

1.32

Spacer mix (liquid)

0

0.932

Tuf Additive No. 1

0

1.23

Tuf Additive No. 2

0

0.88

Tuf Plug

0

1.28

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Responses

  • reiss kelly
    What is the specific gravity of bentonite?
    8 years ago
  • nicola
    What is the water requirement for a typical 15.8ppg cement slurry?
    11 months ago
  • Kiros Kiros
    What is the calculations for water requirements?
    8 months ago

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