Chemistry

Question 1

what is the grain size of portland cement?

Answer 1

From 1 to 100 microns

Question 2

How much gypsum is added to portland cement during the manufacturing process?

Answer 2

3% to 5%

Question 3

Identify the component of the clinker that corresponds to the description Affect the long term and final compressive strenght of cement

Answer 3

C2S

Question 4

What is HSR cement?

Answer 4

High Sulphate Resistant

Question 5

API Class G and Class H cements are extensively used in the oil fields over a wide range of depth, temperature and pressures, the main difference between these API cmenet is?

Answer 5

Class H contains more silicate than the Class G

Question 6

What are the reasons for using double (or multi) stage cementing job?

Answer 6

Reduce risk of breaking down a weak formation, reduce the quantity of cement to be used

Question 7

In a two stage job, when should we wait on the first stage cement to set before pumping the second stage cement slurry?

Answer 7

When the hydrostatic of the second stage may fracture the formation

Question 8

What are the steps for a two stage cementing job

Answer 8

Mud circulation
Pressure test
Pump 1st stage spacer and slurry
Drop 1st stage plug and start displacement
Bump 1st stage plug, bleed off, check returns
Drop opening bomp
Presure up, open stage collar
Stablish circulation
Pump 2nd stage spacer and slurry
Drop closing plug and start displacement
Bump closing plug
Close stage collar

Question 9

Select the possible casing hardware elements that could be found in a liner cementing job?

Answer 9

Wiper plug, Dart, Landing collar, Float shoe, Liner Hanger

Question 10

Why would we use a liner?

Answer 10

In deep wells, where the rig might not stand the weight of a casing string.
Economics
Cover corroed/Damaged casing

Question 11

Why would we use two stage cementing?

Answer 11

Selective cementing of annulus ( Parts of annulus can be left uncemented)
Separation and isolation of special zones- Salt, weak formations… etc
Hydrostatic limitations

Question 12

Surface area of cement grains have influence on the following properties:

Answer 12

Compressive strenght
Slurry rheology
Thickeninig time

Question 13

you are mixing a cement with 38% BWOC water/cement ratio, wich API class is this cement?

Answer 13

Class H

Question 14

what are the main hydratation products for C3S and C2S

Answer 14

CSH gel

Portlandite

Question 15

Which of the statements below describes what happens when the cement is exposed to sulphates?

Answer 15

Sulphates react with unreacted ettringite forming gypsum

Question 16

What mineral is added to the clinker during the final grinding phase of the cement manufacturing process?

Answer 16

Gypsum

Question 17

What is the major component of clinker?

Answer 17

C3S

Question 18

What are the main 2 families of raw materials used to manufacture cement?

Answer 18

Calcareous & Agrillaceous

Question 19

Concerning the chemical composition of cements, what is the component and concentration of it that makes the cement HSR?

Answer 19

less than 3% of C3A

Question 20

Component of the clinker that once hydrated, it is increasing the risk of set cement attecked by shlphate

Answer 20

C3A

Question 21

Component of clinker that contributes to all stages of strenght development?

Answer 21

C3S

Question 22

Portland cement is a hydraulic cement, such cements set and develop compressive strength as a result of a dehytratation

Answer 22

False

Question 23

You need to protect yourself very carefully with PPE against any contact with cement slurry because?

Answer 23

It is strongly basic and it will burn the skin

Question 24

Identify the component of the clinker that corresponds to has the highest heat of hydratation?

Answer 24

C3A

Question 25

Why is gypsum added to the cement?

Answer 25

Give SR properties to the cement

Question 26

The average specific gravity (SG) of a grain of cement is?

Answer 26

3.15 - 3.20

Question 27

What will happen with cement slurry if you have too much gypsum dehydratation in the cement blend?

Answer 27

False Set

Question 28

Portland cement will react at different rate depending on grain size, Based on that wich of the following type of API cmeent will react faster during the hydration process?

Answer 28

Class C