![Chemistry and Classification of Oilwell Cements](/wp-content/uploads/2022/07/Chemistry-and-Classification-of-Oil-well-Cements-780x470.webp)
Assignment
Basic Cement Slurry Formulation
Using the data provided, calculate the quantity of cement slurry and post-flush fluid required to cement the intermediate string of casing in the Assignment Well. Include a 25% cement contingency.
Casing String | Hole Diameter Dhole (in) | Hole Depth* (feet) | Casing Shoe Depth* L (feet) | Depth to Float Collar* (feet) | Casing OD (in) | Casing ID (in) |
---|---|---|---|---|---|---|
Conductor [c] | 30 | 80 | L4=80 | N/A | 20 | 19 |
Surface [s] | 17.5 | 1510 | L3=1505 | 1465 | 13.375 | 12.615 |
Intermediate [i] | 12.25 | 4015 | 4008 | 3968 | 9.625 | 8.835 |
Summary Table
* All depths measured from Rotary Kelly Busing (RKB)
![Cement Slurry and Post-flush Fluid Volumes](/wp-content/uploads/2022/07/Cement-Slurry-and-Post-flush-Fluid-Volumes.webp)
The fluid volume required to cement the intermediate string of casing of the Assignment well is 692 ft3 without contingency. Class H cement and water is being used for this job.
Part A:
Calculate the number of cement sacks needed, including a 25% contingency.
Part B:
Calculate the volume of mix water needed.
Solution
Part A Solution:
According to API Cement Slurry Specifications the yield for a Class H cement =
The cement needed for the intermediate string plus 25% of contingency =
Part B Solution:
According to API Cement Slurry Specifications the water/cement ratio for a Class H cement =
The amount of mix water needed =Â
Assessment
1. API cements are classified according to what oilwell conditions? (Select all that apply.)
A .Mix water
B .Additives
C .Pressure ✔
D .Depth ✔
E .Temperature ✔
Oilwell cements set and develop compressive strength as a result of ________.
A .pressure
B .aeration
C .dehydration
D .hydration ✔
How is a cement slurry mixture categorized if it contains no additives?
A .Common
B .Neat ✔
C .Portland
D .Ordinary
Water in excess of that required for cement to set is necessary for the formation of __________ that can be pumped.
A .a cement slurry ✔
B .aluminosilicates
C .interlocking crystalline structures
What is the recommended ratio of water to cement for mixing oilwell cement?
A .About 5.0 to 6.3 gallons per 94 lbm sack of dry cement, depending on the API Class ✔
B .About 2.8 to 7.3 gallons per 94 lbm sack of cement, depending on the API Class
C .About 4.0 to 5.3 gallons per 94 lbm sack of dry cement, depending on the API Class
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