Assignment
Cement Job Design: Thickening Time Tests
You are continuing with the design of the Assignment well, and the initial formulation for the cement slurry has been sent to a lab for testing.
You have determined the following about this cement operation:
- Requires 145 bbl of cement and 300 bbl of displacement fluid
- Will be pumped at 2.5 barrels per minute
- Will use Class H cement, and D13R retarder (if any)
The total depth is 8000 ft and the BHST is 125 °F.
The consistometer results have returned with the following graph:
Assume it will take 1 hour to pump the job and you want a 1 hour contingency time to ensure the cement has plenty of time to be pumped into position.
Using the data in the table provided, what recommendations do you think are necessary to continue the job?
Solution
Total pump volume is 
At 2.5 
pump rate, pump time is 
.
Assuming 1 hour safety factor, and 1 hour contingency time, the total setting time required is 5 hours. Based on data provided in the table, this means you will need to add 0.3% D13 R to the slurry.
Assessment
1. How is API fluid loss value determined?
A .By measuring how much water collects at the top of a cylinder of slurry after 10 minutes
B .Through collected filtrate volume multiplied by a factor of 2 ✔
C .Through the measurement of cement slurry density before it is heated
2. Thickening time tests are used to determine the time that cement slurry will remain pumpable under what conditions? (Select all that apply.)
A .Downhole conditions ✔
B .Dynamic wellbore conditions ✔
C .Over-retardation conditions
3. Thickening time is measured using a __________.
A .pressurized density balance
B .rotational viscometer
C .triaxial gel strength analyzer
D .consistometer ✔
4. The API and ISO cement testing recommended practices are designed to__________.
A .precisely simulate actual downhole conditions in a well
B .occur only in laboratories
C .allow comparison of results among different cement formulations ✔
D .occur only on location
5. If the slurry is going to be mixed in a batch mixer, the slurry sample should be transferred to a _________ for continuous stirring in a manner consistent with expected field conditions.
A .consistometer ✔
B .sedimentation tube
C .viscometer
D .filter press
6. A crush test for determining compressive strength is carried out on cement cubes of what size?
A .1 inch cubes
B .4 inch cubes
C .2 inch cubes ✔
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