This document discusses cement manufacturing and composition, the objectives of cementing, and parameters for designing cement slurries. It notes that Portland cement is made from limestone and clay which react at high temperatures to form clinker. Cement consists mainly of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite. The key objectives of cementing are to restrict fluid movement, support the casing, protect from corrosion, and stop lost circulation. Successful cementing requires proper design considering well parameters, cement additives, and procedures. Slurry properties like density, thickening time, rheology, fluid loss, strength, and retrogression must be considered in

1. Presentation by
Amit Nitharwal
B.Tech 3rd year Petroleum engineering
University college of engineering, RTU, Kota

2. Cement Manufacturing & Composition
 Portland cement’s basic raw material:
limestone and clay.
 Oxides of Ca, Al, Fe, Si react at high
temperatures in the Kiln (1450– 1500 ⁰C ).
 When it cools, it becomes balls of cement
clinker.
 After aging in the storage, the seasoned
clinker is taken to the grinding mills where
gypsum is added to (CaSO4.2H2O) to retard
setting time and increase ultimate strength.

3. composition
Cement is thought to be made up of four
crystalline components in the clinker that
hydrate to form a rigid structure.
1. Tricalcium silicate (3 CaO.SiO2
or C3S)
2. Dicalcium silicate (2 CaO.SiO2
or C2S)
3.Tricalcium Aluminate (3
CaO.Al2O3 or C3A)
4.Tetracalcium aluminoferrite
(4CaO.Al2O3.Fe2O3C4AF)

4. Objective of cementing
 The most important factor in the well
completion operation is obtaining a
satisfactory primary cementing job.
 The principle functions of primary cementing
are:-
1)To restrict fluid movement between formati0n
2)To support the casing
3)To protect the casing from corrosion
4) Stop the movement of fluid into regular &
fractured formations(lost circulation)

5. Successful cementation
 Good cementation job design.
 Designer’s knowledge about fluids.
 Cement additives
 Procedures to be used in given well condition

6. Cement slurry design parameters
 Well depth, diameter and casing size.
 Bottom hole static temperature(BHST) .
 Bottom hole circulating temperature(BHCT).
 Bottom hole pressure(BHP).
 Mud density
 Samples of available cement lot.
 Cement additives.
 Water that will be used at the asset.

7. Cement slurry properties
 Slurry density
 Thickening time
 Rheology
 Fluid loss control
 Free water content
 Compressive strength
 Strength retrogression
All these properties should be taken care to
maintain well security & integrity

8. Slurry density
Density of cement slurry is adjusted to:-
 Balance the formation pressure
 Control the loss of slurry in weak zones
 The effective mud removal.
Note :-
 Normally slurry density is kept higher than
mud for facilitating the displacement of
drilling mud from annulus.
 The density difference of .2 to.5 gm/cc is
normally recommended b/w mud and cement
slurry.

9. Density determined by using
mud balance

10. Thickening time
Definition :-Thickening time tests are designed
to determine the length of time for which a
cement slurry remains in a pumpable state
under simulated wellbore conditions of
temperature and pressure.
 Total time required to pump the
cement slurry into the well bore safely.
 Normally TT = Job time + 1 hour.
 Excessive TT causes free water pocket
formation & settling of cement

11. HP-HT consistometer
 High pressure-High temperature consistometer.
 The pumpability, or consistency, is measured in
Bearden Consistency units (BC).
HP-HT consistometer

12. RHEOLOGY
 Flow behavior of fluids under applied stress.
 Applied force induces flow in liquids.
Types Of Flow
 Laminar
 Turbulent
 Plug
 Slurry is designed for turbulent flow or plug flow.
 In wells with low annular clearance turbulent flow
is desirable for good mud displacement.

13. Rheology of cement slurry
govern
 Mud displacement in the annulus
 Frictional pressure drop in annulus
 Hydraulic horse power required to place the
cement
Note :- By adding (dispersants), the physical
properties of fluid are modified in turn
controls the flow velocity, pumping rate &
pressure losses.

14. fann viscometer
 The slurry sample should be conditioned for 20
minutes in an atmospheric consistometer before
measurements are taken.
 Readings should be taken at ambient conditions and
at BHCT when possible.
 Readings should also be reported at 200, 100, 60, 30,
6 and 3 rpm.

15. fluid loss control
 Fluid-loss tests are designed to measure the
slurry dehydration during, and immediately
after cement placement.
 The slurry is tested for filtrate loss across a
standardized filter press at differential
pressures of 1000 psi.
 Poor F/L control may lead to
 Loss of water to formations.
 Change of W/C ratio
 Increase in slurry viscosity & unpumpability
 Lost circulation

16. HP-HT filter press
 The test duration is 30 minutes and results
are quoted as ml/30 min
 ml / 30 min = (ml*84.84) / Sq.root of t in
Sec.

17. free water content
Quantity of water separates out from
slurry in 2 hrs. under static conditions.
Permissible limit = 1.4% max.
Excessive free water causes:
water pockets
 settling
micro channeling
 % of free water= ml of free water*1.9
7.6

18. Compressive Strength
Strength developed by a cement depends on
 W/C ratio
 BHST
 Time
 Expressed in Psi
 Minimum strength to hold casing = 500
psi
 Low W/C ratio – high strength
 35-40% silica is added to prevent strength
retrogression.

19. compressive strength testing m/c
 The slurry samples are cured for 24, 48 and 72
hours at bottom-hole static temperatures
and pressures to form cement stone of 2 inch
.
 The above cement stone is then broken in the
strength testing m/c.
 Calculations :-
KN*3.92 = Kg/cm2
Kg/cm2 *14.225 = Psi

20. Strength Retrogression
 The Compressive Strength of the cement stone
above 110o c Start decreasing and as a result
permeability of the cement stone increases.
 Normally 30-35% Silica flour is added to the
cement slurry to combat the Strength
retrogression of cement stone.
 Fine Silica flour addition also reduces
Permeability of set cement.
 At this temp, Silica Combines with Free lime to
form durable cementations material and arrests
Strength retrogression.

21. Cement additives
 With the use of additives cement slurry design can
be modified according to the well requirements.
 At present the cement class G can be modified
easily through the use of additives .
Types of cement additives:
 Accelerators
 Retarders
 Extenders
 Dispersant
 Fluid loss additives
 Anti-gas migration additives
 Special materials:- Antifoam, silica, suspending,
weighting

22. Accelerators
 Accelerating a slurry means shortening the
ThickeningTime or reducing the time required
to gain Compressive Strength or both.
 To reduce the thickening time as well as
increase the rate of early strength .
 Used for shallow, low temp. & pressure
well.
 Examples :- 1) NaCl ( 3-10% BWOW )
2) CaCl2 ( 2-4% BWOC

23. Retarders
 A material that allows sufficient time for
slurry placement by delaying the set of the
cement is called a retarder.
 Retarders delay the hydration of cement to
provide sufficient time to pump slurry in the
well.
 Increase thickening time but also delay
strength development.
 Needed when
 Long pumping times are required.
 Temperatures are high.

24. Brand
Name
Manufacturer EffectiveTemp.
Range
Property
HR-4 Halliburton Up to 76 ºC Solid brown powder -Calcium
Lignosulphonate derived from
wood.
HR-5 Halliburton 52 ºC to 97 ºC Black, solid powder -chemically
modified lignosulphonate.
HR-12 Halliburton 104ºC to
171ºC
Yellowish-brown powder -is a
mixture of HR-4 retarder and an
organic acid.

25. EXTENDERS
 Extenders are the additives that reduce slurry
density and increase slurry yield.
Most allow the addition of extra water to
slurry
 Cement may be lightened to protect the weak
formations or slurry yield may be increased to
reduce the cost.
 Examples :-
 Bentonite, Sodium silicate
 Pozzolans (Diatomaceous earth, Fly ash, Fume
silica

26. Fluid Loss Additives
 Fluid loss material is added to the cement slurry to
help minimize the loss of water from the slurry into
the formations.
 Works by viscosifying the mix water or by plugging
the pore throat in the filtrate cake with long
polymer chains.
 Recommended and acceptable filtration loss for
various job are:-
 For casing cementation ----------- 100-200 ml/30min.
 For liner & squeeze job----------- 50-150mi/30min.
 For Gas wells ------------------------------50mi/30min.

27. Examples
 Organic polymers (Cellulose)
 Poly( ethyleneimine )
 Polyallylamine
 Halad-9 (15.5 ºC to 149ºC)
 Halad-413 (Up to 204º C)

28. DISPERSANTS
 Dispersants are also called friction reducers,
these materials make cement slurries easier
to mix and pump.
 Also called friction reducers, these materials
make cement slurries easier to mix and pump
by making them less viscous.
 Act on surface charges of the cement grains.
 Polyanions- polymelamine,
polynapthalene, polystyrene sulpfonates
 Examples :- CFR-3

29. Anti gas migration additives
 Gas migration control additives are used to
reduce the risk of gas invading the cement
and migrating into the wellbore.
 Examples :- 1) BA-10S
2) BA-10L

30. Heavy weighting additives
 Weighting material are cement additives that are
capable of increasing the density of the cement
slurry.
 These are required to counter high formation
pressures.
 Common high density materials are:-
 Hematite
 Barite (Barite is a barium sulfate material used to
weight drilling mud and cement slurries)

31. Thanks for your
attention