Cement Head Theory and operations. Flashcards
What are the two types of cement head?
- Conventional cement heads
* Schlumberger EXPRES* cementing heads.
To release a top plug in a double plug conventional cement head put the steps in the correct order:
-After 40 to 50 bbl of displacement open the middle and bottom hammer valves to allow the displacement fluid to clear any cement residue from all internal lines in the cement head
-Unscrew the top pull pin to release the plug
-Open the top hammer valve to equalize pressure between top and middle hammer valve.
-Close the middle hammer valve.
Resume pumping with displacement fluid and the top plug is forced down the well bore.
-Open the top hammer valve to equalize pressure between top and middle hammer valve.
-Unscrew the top pull pin to release the plug
-Close the middle hammer valve.
Resume pumping with displacement fluid and the top plug is forced down the well bore.
-After 40 to 50 bbl of displacement open the middle and bottom hammer valves to allow the displacement fluid to clear any cement residue from all internal lines in the cement head
What are the currently brands used in conventional cement heads? • Schlumberger OCT • Gray Tool Group • UIE • Industrial Rubber (IRI)
Industrial Rubber (IRI) the only supplier UIE cement heads (still in use in some locations)
What are the two models of conventional cement heads?
- single-plug cement head
* double-plug cement head.
why does the single-plug conventional cement head represent higher risk to the operator than the double-plug one.
- The top cover has to be removed to load the top plug.
- Loading the top plug may occur high above the rig floor.
After the top plug is in the wellbore which valves are opened i the cement head to allow the displacement fluid to clear the cement residue?
Bottom valve and middle valve
Pressure rating of a cement head should always be checked after pressuring up the system?
false
To release a bottom plug in a double plug conventional cement head put the following steps in correct order:
- Unscrew the bottom pull pin to release the bottom plug.
- Resume pumping. The force of the cement slurry forces the bottom plug down the wellbore
- Close the bottom hammer valve.
- Open the middle hammer valve to equalize the pressure between the middle and lower valves.
- Open the middle hammer valve to equalize the pressure between the middle and lower valves.
- Unscrew the bottom pull pin to release the bottom plug
- Close the bottom hammer valve.
- Resume pumping. The force of the cement slurry forces the bottom plug down the wellbore
Conventional heads are safer than EXPRES* Heads?
False
why are EXPRES heads safer than conventional heads?
- they are smaller and lighter
- Remotely controlled
- Easier to install on the casing
- Use a quick-connect to the plug launcher
What is the maximum working pressure of an EXPRES head?
7500 psi
what is the max BHCT the plugs used with the EXPRES head can handle?
300 degrees F
A pump rate of 3 bpm should not be exceeded when dropping a plug on the fly?
true
what is the meaning of the acronym EXPRES?
EXtrusion Plug RElease System
Name the components of an EXPRES head?
Plug departure detector Plug basket handling tool Power pack Air hose Hydraulic Launcher
Name the features of the EXPRES head?
High-performance plug Plug container Safety Modular system Remote control
what is EXPRES latch coupler
manually operated device that seals the EXPRES head on the top of any casing coupling
Name a not benefit for EXPRES latch coupling
Higher pressure ratings.
Which of the following is highly pressure-energized by a wave spring? -Piston Safety Pin Coupling Seal Casing Collar
Coupling seal
Which of the foll latches the ELC underneath the collar? External handles Set of dogs Rotating cams Safety pins
Set of dogs
What represent force applied to the seal?
(Couper seal OD area - Casing colar ID area)x Pressure
The express latch coupler is an automatic device that seals the EXPRES head on top any caising.
False is manually operated device
name benefits of deep sea Express:
Remote control release of darts
Fluids are not pumped through the inside of the plugs
Plugs qualified at high combined pressure and temperature.
No contamination of fluids
Surface pressure provides positive indication of each plug release
Pumping is stopped for a few seconds during darts release
Remote control release of darts
Fluids are not pumped through the inside of the plugs
Plugs qualified at high combined pressure and temperature.
No contamination of fluids
Surface pressure provides positive indication of each plug release
cement slurry
is placed in the annulus in one stage. This
technique uses two plugs to prevent the
intermixing of cement with other fluids used in
the operation.
Single-stage cementing
Two-stage cementing refers to the placement of
slurry around a lower and an upper portion of a
casing string
Two-stage cementing
what is the main purpose of a two stage cementing?
The main pupose of two-stage cementing is to
isolate two problem zones within one open hole
section
is the placement of a relatively
small volume of slurry anywhere in the
wellbore
plug cementing
is the process of forcing
slurry under pressure through holes or splits in
the casing or wellbore annular space
remedial cementing
The objectives of remedial cementing include
- Repair improper zonal isolation.
- Raise the top of the cement.
- Plug perforations.
- Repair corroded casing.
Plug functions
• separate fluids and prevent contamination
• clean inner casing wall
• provide surface indication when
displacement is complete
what is the pressure to rupture the bottom plug diaphragm?
The pressure to rupture a diaphragm is approximately 150-500 psi
what does the bottom plug?
- cleans the casing wall
* provides a seat for the top plugs.
what does the top plug?
- cleans the casing wall
- indicates end of displacement
- follows the slurry to prevent contamination.
What is the working pressure of the fabricated cement head?
5,000 psi
What is the working pressure of the integral cement head?
10,000 psi
some characteristics of the integral cement head?
approved welded construction
manifold has an approved threaded design.
machined out of one piece of stock
with female ACME
Arrange the steps in a cement job in order:
___ A. Prepare the casing.
___ B. Drop the top plug.
___ C. Drop the bottom plug.
___ A. Prepare the casing.
___ C. Drop the bottom plug.
___ B. Drop the top plug.
- What are the two types of cement heads
currently used in Schlumberger?
A. fabricated
B. integral
- What is the pressure rating for a single
plug fabricated 9-5/8-in cement head?
5000 psi
- What is the definition of the tattletale?
C. A physical indicator. It shows the operator that the plug has left the cement head
- If the tattle-tail of the twin path slings does
not extend past the black line, which of the
following actions should be taken?
B. Remove the sling from service
What three factors must be taken into
account when choosing the cement head
and adapter for the job?
A. casing size
C. casing thread
D. bail size
What distinguishes a top plug from the
bottom plug?
the top plug is solid; the bottom plug is
hollow
When leaving the district, the plug valves
should be in which position?
top valves shut, bottom valves in open
position
The primary function of the _________
is to enable the casing to be tripped in
with relative ease, preventing jamming in
washed-out zones or deviated wells.
guide shoe
