Calculation of cementing operation on location From this oil well data below Casing 13 3/8” id 12.715”, 48 lb/ft weight Casing 9 5/8” id 8.9821”, 36 lb/ft weight Open hole 12 ¼” well fluid 8.6 ppg Calculate : Volume of cement per feet, Volume of cement, Cement for 1500 ft, Sak of cement, Mix water require, Displace fluid required, Hydrostatic pressure outside casing, Hydrostatic pressure inside casing, Buoyancy factor, Differential pressure, Area, Push up pressure, Push down pressure, Total push, Bump plug pressure
Target Depth 13 3/8” (48 lb/ft) casing 50 ft
Open hole 12 ¼” depth to 1510 ft 1460 ft Tatget Depth 9 5/8” (36 lb/ft) casing 1500 ft -
Calculation capacity casing 13 3/8” Capacity casing 13 3/8” = 𝑖𝑑 2 𝑥 0.0009714
Target Depth 13 3/8” (48 lb/ft) casing 50 ft
Open hole 12 ¼” depth to 1510 ft
Capacity casing 13 3/8” = 12.252 𝑥 0.00097141460 ft Capacity casing 13 3/8” = 0.1458 bbl/ft -
Calculation capacity casing 9 5/8” For internal use only
Tatget Depth 9 5/8” (36 lb/ft) casing 1500 ft
Capacity casing 9 5/8” = 𝑜𝑑 2 𝑥 0.0009714 Capacity casing 9 5/8” = 9.6252 𝑥 0.0009714 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 𝑐𝑎𝑠𝑖𝑛𝑔 9 5/8" = 0.0899 𝑏𝑏𝑙/𝑓𝑡 Capacity casing 9 5/8” = 𝑖𝑑 2 𝑥 0.0009714 Capacity casing 9 5/8” = 8.9212 𝑥 0.0009714 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 𝑐𝑎𝑠𝑖𝑛𝑔 9 5/8" = 0.0733 𝑏𝑏𝑙/𝑓𝑡 -
Calculation capacity open hole 12 ¼” Capacity open hole 12 1/4” = 𝑜𝑑 2 𝑥 0.0009714 Capacity open hole 12 1/4” = 12.252 𝑥 0.0009714 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 𝑜𝑝𝑒𝑛 𝑜𝑙𝑒 = 0.1458 𝑏𝑏𝑙/𝑓𝑡
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Volume of cement 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 = 𝑖𝑑 13 3/8" − 𝑜𝑑 9 5/8" 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 = 0.1571 − 0.0899 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 = 0.0671 𝑏𝑏𝑙/𝑓𝑡
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Cement for 500 ft 𝐶𝑒𝑚𝑒𝑛𝑡 𝑓𝑜𝑟 500 𝑓𝑡 = 500 𝑓𝑡 𝑥 0.0671 𝑏𝑏𝑙/𝑓𝑡 𝐶𝑒𝑚𝑒𝑛𝑡 𝑓𝑜𝑟 500 𝑓𝑡 = 33.55 𝑏𝑏𝑙
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Cement for 1500 ft 𝐶𝑒𝑚𝑒𝑛𝑡 𝑓𝑜𝑟 1500 𝑓𝑡 =
1500 − 500 𝑥 0.0559 + 20% 𝑥 𝑖𝑑 𝑂𝐻 12 1/4" − 𝑜𝑑 9 5/8"
𝐶𝑒𝑚𝑒𝑛𝑡 𝑓𝑜𝑟 1500 𝑓𝑡 =
1500 − 500 𝑥 0.0559 + 20% 𝑥 12.25 − 8.921
𝐶𝑒𝑚𝑒𝑛𝑡 𝑓𝑜𝑟 1500 𝑓𝑡 = 56.1 𝑏𝑏𝑙 -
Total cement require 𝑇𝑜𝑡𝑎𝑙 𝑐𝑒𝑚𝑒𝑛𝑡 𝑟𝑒𝑞𝑢𝑖𝑟𝑒 = 33.55 + 56.1 𝑇𝑜𝑡𝑎𝑙 𝑐𝑒𝑚𝑒𝑛𝑡 𝑟𝑒𝑞𝑢𝑖𝑟𝑒 = 89.65 𝑏𝑏𝑙
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Sak of cement 𝑆𝑎𝑘 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 = (89.65 𝑏𝑏𝑙 𝑥 5.6146)/1.162 𝑓𝑡 3 /𝑠𝑎𝑘 𝑆𝑎𝑘 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 = 433.1746 𝑠𝑎𝑘
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Mix water From halliburton red book for slurry without any other additive require 5.069 gal/sak, so mix water the requirement are: 𝑀𝑖𝑥 𝑤𝑎𝑡𝑒𝑟 = (5.069 𝑔𝑎𝑙/𝑠𝑎𝑘 𝑥 433 𝑠𝑎𝑘)/42 𝑔𝑎𝑙/𝑏𝑏𝑙 𝑀𝑖𝑥 𝑤𝑎𝑡𝑒𝑟 = (2194.877 𝑔𝑎𝑙)/42 𝑔𝑎𝑙/𝑏𝑏𝑙 𝑀𝑖𝑥 𝑤𝑎𝑡𝑒𝑟 = 52.259 𝑏𝑏𝑙 Excess tank estimated 10 bbl, so the water requirement are 52.259 bbl + 10 bbl = 62.259 bbl
For internal use only
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Displace fluid 𝐷𝑖𝑠𝑝𝑙𝑎𝑐𝑒 = 1500 𝑓𝑡 – 40 𝑓𝑡 𝑥 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 𝑐𝑎𝑠𝑖𝑛𝑔 𝐷𝑖𝑠𝑝𝑙𝑎𝑐𝑒 = 1500 𝑓𝑡 – 40 𝑓𝑡 𝑥 0.0773 𝑏𝑏𝑙/𝑓𝑡 𝐷𝑖𝑠𝑝𝑙𝑎𝑐𝑒 = 112.858 𝑏𝑏𝑙
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Hydrostatic outside casing for slurry with density 15.8 ppg inside casing 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑜𝑢𝑡𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = (𝑑𝑒𝑛𝑠𝑖𝑡𝑦/19.25 𝑙𝑏𝑠) 𝑥 𝑙𝑒𝑛𝑔𝑡 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑜𝑢𝑡𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = (15.8 𝑝𝑝𝑔/19.25 𝑙𝑏𝑠) 𝑥 1500 𝑓𝑡 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑜𝑢𝑡𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = 1231.2 𝑝𝑠𝑖
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Hydrostatic inside casing For water with density 8.33 ppg outside casing 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑖𝑛𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = (𝑑𝑒𝑛𝑠𝑖𝑡𝑦/0.052) 𝑥 𝑙𝑒𝑛𝑔𝑡 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑖𝑛𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = (8.33 𝑝𝑝𝑔/0.052) 𝑥 1460 𝑓𝑡 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑖𝑛𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = 632.5 𝑝𝑠𝑖 for slurry with density 15.8 ppg outside casing along 40 ft are: 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑖𝑛𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = 0.8208 𝑥 40 𝑓𝑡 𝐻𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑖𝑛𝑠𝑖𝑑𝑒 𝑐𝑎𝑠𝑖𝑛𝑔 = 32.8 𝑝𝑠𝑖 Total hydrostatic inside casing = 632.5 psi + 32.8 psi = 665.3 psi
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Buoyancy factor for well fluid with density of 8.6 ppg 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 65.445 8.6 𝐵𝑢𝑜𝑦𝑎𝑛𝑐𝑦 𝑓𝑎𝑐𝑡𝑜𝑟 = 1 − 65.445 𝐵𝑢𝑜𝑦𝑎𝑛𝑐𝑦 𝑓𝑎𝑐𝑡𝑜𝑟 = 1 −
𝐵𝑢𝑜𝑦𝑎𝑛𝑐𝑦 𝑓𝑎𝑐𝑡𝑜𝑟 = 0.8686 -
Differential pressure 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑜𝑢𝑡𝑠𝑖𝑑𝑒 – 𝑦𝑑𝑟𝑜𝑠𝑡𝑎𝑡𝑖𝑐 𝑖𝑛𝑠𝑖𝑑𝑒 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 1231.2 𝑝𝑠𝑖 − 665.3 𝑝𝑠𝑖 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 565.9 𝑝𝑠𝑖
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Area 𝑎𝑟𝑒𝑎 = 𝐼𝑑2 𝑥 0.7854 𝑎𝑟𝑒𝑎 = 9.6252 𝑥 0.7854 𝑎𝑟𝑒𝑎 = 72.76
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Push up 𝑃𝑢𝑠 𝑢𝑝 = 𝑑𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑥 𝑎𝑟𝑒𝑎
For internal use only
𝑃𝑢𝑠 𝑢𝑝 = 565.9 𝑥 72.76 𝑃𝑢𝑠 𝑢𝑝 = 41174.884 𝑙𝑏𝑠 -
Push down 𝑃𝑢𝑠 𝑑𝑜𝑤𝑛 = 𝑙𝑒𝑛𝑔𝑡 𝑥 𝑐𝑎𝑠𝑖𝑛𝑔 𝑤𝑒𝑖𝑔𝑡 𝑥 𝑏𝑜𝑢𝑦𝑎𝑛𝑐𝑦 𝑓𝑎𝑐𝑡𝑜𝑟 𝑖𝑛𝑠𝑖𝑑𝑒 + ( 𝑙𝑒𝑛𝑔𝑡 𝑥 0.76) 𝑃𝑢𝑠 𝑑𝑜𝑤𝑛 = 1460 𝑓𝑡 𝑥 36 𝑙𝑏/𝑓𝑡 𝑥
1−
8.6 + 40 𝑓𝑡 𝑥 0.76 65.45
𝑃𝑢𝑠 𝑑𝑜𝑤𝑛 = 45757.6 𝑙𝑏𝑠 -
Total push 𝑇𝑜𝑡𝑎𝑙 𝑝𝑢𝑠 = 𝑝𝑢𝑠 𝑢𝑝 – 𝑝𝑢𝑠 𝑑𝑜𝑤𝑛 𝑇𝑜𝑡𝑎𝑙 𝑝𝑢𝑠 = 41174.884 𝑙𝑏𝑠 – 45757.6 𝑙𝑏𝑠 𝑇𝑜𝑡𝑎𝑙 𝑝𝑢𝑠 = −4582.716 𝑙𝑏𝑠 Negative sign tell us that the force pressure downward higher than upward pressure, so in the cementing operation the cementing head need no changing.
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Bump plug 𝐵𝑢𝑚𝑝 𝑝𝑙𝑢𝑔 = 𝑑𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 + 500 𝑝𝑠𝑖 𝐵𝑢𝑚𝑝 𝑝𝑙𝑢𝑔 = 565.9 + 500 𝑝𝑠𝑖 𝐵𝑢𝑚𝑝 𝑝𝑙𝑢𝑔 = 1065.9 𝑝𝑠𝑖
After bump plug pressure acquired, we have to know the casing brush pressure for that grade, only to make sure that casing will not brush when the cementing operation carry out. After reading that cementing operation calculation we also need to know how to calculate slurry yield within the cement laboratory, which usually base on fluid from a future cementing location took place. Here the laboratory calculation Laboratory calculation What is the density in lb/gal, slurry yield in ft3/sack, water requirement in gal/sack, for slurry with G type cement 94 lb or 426.38 gram in a sack, bila if the cement use as a sample are 100 gram, and water percentage as shown on the table below ?
For internal use only
Cement
Water required
%
API class C API class A API class G API class H
6.3 gal/94-lb sak 5.2 gal/94-lb sak 5.0 gal/94-lb sak 4.3 gal/94-lb sak
56 46 44 38
API cement grade table Answer : -
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 = 𝑐𝑒𝑚𝑒𝑛𝑡 𝑤𝑒𝑖𝑔𝑡 𝑥 𝑤𝑎𝑡𝑒𝑟 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 = 100 𝑥 0.44 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 = 44 𝑐𝑚3
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𝑉𝑜𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 =
𝑐𝑒𝑚𝑒𝑛𝑡 𝑤𝑒𝑖𝑔 𝑡 3.14
𝑉𝑜𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 =
100 3.14
𝑉𝑜𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 = 31.85 𝑐𝑚3 -
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑙𝑢𝑟𝑟𝑦 = 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 + 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑙𝑢𝑟𝑟𝑦 = 44 + 31.85 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑙𝑢𝑟𝑟𝑦 = 75.85 𝑐𝑚3
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𝑇𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑠𝑙𝑢𝑟𝑟𝑦 = 𝑐𝑒𝑚𝑒𝑛𝑡 𝑤𝑒𝑖𝑔𝑡 + 𝑤𝑎𝑡𝑒𝑟 𝑤𝑒𝑖𝑔𝑡 𝑇𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑠𝑙𝑢𝑟𝑟𝑦 = 100 + 44 𝑇𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑠𝑙𝑢𝑟𝑟𝑦 = 144 𝑔𝑟𝑎𝑚
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𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 𝑡𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑠𝑙𝑢𝑟𝑟𝑦/𝑣𝑜𝑙𝑢𝑚𝑒 𝑠𝑙𝑢𝑟𝑟𝑦 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 144𝑔𝑟𝑎𝑚/75.85 𝑐𝑚3 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 1.89 𝑔𝑟𝑎𝑚/𝑐𝑚3 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 1.89 𝑔𝑟𝑎𝑚/𝑐𝑚3 𝑥 8.34134 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 15.76 𝑙𝑏/𝑔𝑎𝑙 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 15.8 𝑝𝑝𝑔
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𝑊𝑎𝑡𝑒𝑟 𝑟𝑒𝑞𝑢𝑖𝑟𝑒 𝑝𝑒𝑟 𝑠𝑎𝑐𝑘 𝑐𝑒𝑚𝑒𝑛𝑡 = 𝑣𝑜𝑙𝑢𝑚𝑒 𝑤𝑎𝑡𝑒𝑟 𝑥 𝑐𝑒𝑚𝑒𝑛𝑡 𝑖𝑛 𝑠𝑎𝑐𝑘 𝑊𝑎𝑡𝑒𝑟 𝑟𝑒𝑞𝑢𝑖𝑟𝑒 𝑝𝑒𝑟 𝑠𝑎𝑐𝑘 𝑐𝑒𝑚𝑒𝑛𝑡 = 44 𝑥 426.38 𝑊𝑎𝑡𝑒𝑟 𝑟𝑒𝑞𝑢𝑖𝑟𝑒 𝑝𝑒𝑟 𝑠𝑎𝑐𝑘 𝑐𝑒𝑚𝑒𝑛𝑡 = 18760.72 𝑐𝑚3 𝑊𝑎𝑡𝑒𝑟 𝑟𝑒𝑞𝑢𝑖𝑟𝑒 𝑝𝑒𝑟 𝑠𝑎𝑐𝑘 𝑐𝑒𝑚𝑒𝑛𝑡 = 18760.72 /3785.4 𝑊𝑎𝑡𝑒𝑟 𝑟𝑒𝑞𝑢𝑖𝑟𝑒 𝑝𝑒𝑟 𝑠𝑎𝑐𝑘 𝑐𝑒𝑚𝑒𝑛𝑡 = 4.96 𝑔𝑎𝑙/𝑠𝑎𝑘
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𝑠𝑙𝑢𝑟𝑟𝑦 𝑦𝑖𝑒𝑙𝑑 = 𝑤𝑒𝑖𝑔𝑡 𝑜𝑓 𝑎 𝑠𝑎𝑐𝑘/𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑒𝑚𝑒𝑛𝑡 𝑠𝑙𝑢𝑟𝑟𝑦 𝑦𝑖𝑒𝑙𝑑 = 75.85 𝑐𝑚3 /100 𝑔𝑟𝑎𝑚 𝑠𝑙𝑢𝑟𝑟𝑦 𝑦𝑖𝑒𝑙𝑑 = 0.76 𝑐𝑚3 /𝑔𝑟𝑎𝑚 𝑠𝑙𝑢𝑟𝑟𝑦 𝑦𝑖𝑒𝑙𝑑 = 0.76 𝑐𝑚3 𝑥 1.5032 𝑠𝑙𝑢𝑟𝑟𝑦 𝑦𝑖𝑒𝑙𝑑 = 1.14 𝑓𝑡 3 /𝑠𝑎𝑘
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