Chapter 3 Cementing Equipment & Accessories Flashcards
Function of Cement Silos?
To handle homogeneity
Basic Bulk Cementing Equipments
Silo - Surge Tank - Mix bowl - Mixing Tank
Silo -> Surge Tank (small silo/bulk tank. act as buffer. Ensure continuous cmt job. Monitor transfer rate 60-80%. Usually situated next to cmt unit) -> mix tub
Function of Liquid Additive System?
What is the sequence in Liquid Additive Storage & Mixing?
- To set how much volume/concentration of additive needed to enter the mixing tub
-Have centrifugal
Sequence: SAPB
Storage
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Additive metering system
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Parallel water flushed
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Both mixed in mixing tanks
Cement Mixing Units & Recirculation
Cement Mixer - equipment where Water meets Cement and formed Cement Slurry
Recirculation
SurgeTank -> Add Water+Cement -> mixing tub -> pump into hole -> small portion recirculate back into tub (to have uniform rheology of slurry)
Describe Cementing HP Pump:
-a Triplex Pump
- Surge Tank
- small capacity - Holding Tank (mixing tub)
-where G cmt + water + additives are mixed
-mixed at 4bbls/min
-pump downhole while continuously mixing - Recirculating Centrifugal Pump
-to circulate slurry in the holding tank to improve homogeneity
-to feed the slurry to the down hole pump - Intelligent Instrumentation
-to set exact vol/concentration of additives
Function of a Cementing Unit?
To mix and inject the cement slurry into the well
What are the variables required during job -
Mixing, pumping & displacement?
Slurry density
FR
Pressure
Stage & Cumulative volume pumped
What is the optimum rate for Cement Pump?
3-5 bbls/min
If need to pump 500bbls - need 100mins - 1 hr 40m
If 2bbls/min
If need to pump 500bbls - need 250mins - >4hrs
What is a Batch mixer?
-a tank that can hold <100bbls / 200bbls
-capable to mix slurry
-advantages: slurry can be brought up to weight with all the additives, homogenized & tested before pump
Main use in:
(A) Liner setting
- want to ensure no failure. Since it is a small cement job, so deploy Batch Mixer to eliminate on the job problem & can get good slurry
What is High Pressure Discharge Lines/Cementing Iron?
-usually connected to the Cement Head -> HP Cement Manifold -> Down to csg
-got vibration effect in pipe - HSE concerns
-treating lines should be chained down to prevent flying ard
What is Sweges & Cement Head?
Sweges
-allow connection of smaller diameter pipe to casing threads
-pressure rating should be greater than the casing attached (usually larger csg sizes)
Cement Head
-hold hoses from cmt unit
-can hold bottom & top plug
-allow cmt to pass through cmt head
What are the 5 categories of the Cementing Downhole Accessories/Tools?
- Float equipment
- Centralization & flow enhancement tools
- Stage tools
- T & D reduction tools
- Elastomers - casing & liner wiper tools & inflatables
Functions of Float Shoe & Guide Shoe
-tapered
-has a U bullet nose to allow the downhole of casing from hitting rock ledges or washout
-outer made of steel
-internal made of concrete or thermoplastic
-got flow path (valve-one way flow) for cmt to come out from FS & into annulus
Differences of Guide Shoe with Float Shoe?
- internal profile do not have valve check
-to be used only for Conductor/Surface casing
A brief description of the Downhole Accessories.
-The lower end of the casing is protected by a guide shoe or float shoe.
Float Collar:
- is placed one or two joints above the Float Shoe to provide a seat to land cement plugs and to halt cement displacement.
- the short section of casing between the shoe and float collar is called the shoe joint and is provided as a buffer within the casing to contain potential fluid contamination ahead of the top plug.
Plugs
- act as physical barriers
- Barriers to separate the cement slurry from the drilling mud and displacement fluids.
Centralizers
- placed in critical sections to prevent sticking while the casing is lowered into the well
What are the 3 most common types of Check Valves used in casing hardware?
The ball
-does not work well in ERD due to gravity
Flapper
-good for all wells/conditions
Poppet
-spring loaded
-unaffected by hole deviation
-tricky to be used in high solids fluid - may plug the poppet
Material used in valves vary depending on?
-drillability
-compatibility with bits
-temperature stability
What are the 3 major valve materials?
-phenolic resin
-composites
-alloys
What is Float Collar?
-is placed 2 or 3 joints above Float Shoe
-allow the 2 plugs to seat on it & halt cement displacement
What is Cement Plugs?
-to separate cement slurry from
spacer & drilling fluids
-to wipe out the mud film from the interior of the casing string
-to prevent over-displacement of the cement slurry
-to indicate when cement placement is complete thus allowing casing pressure test after cement slurry displacement.
What are the differences of Bottom & Top Plug?
Bottom plugs were developed to precede the cement slurry, requiring an internal bypass or flow- through feature like a thin membrane that is designed to rupture and permit flow once the bottom plug has seated on the float collar further providing a seat for landing top plugs and sealing off displacement.
What is Casing Centralizers?
- centralize casing to give uniform annuli
-to be installed when running casing at surface
Function of Stop Collars
-to hold centralizers in place by fastening it with bolts/scews
What are the 3 types of Centralizers?
Rigid centralizers
Semi-rigid centralizers
Spring bow centralizers
Rigid centralizers
-non flexible bands (cannot adjust to any hole restriction/enlargement)
Semi-rigid centralizers
-good for high angle well/ERD
Spring bow centralizers
-commonly used
-used in low angle well
-bow able to flex easily
