Your Score: 14/20
Not bad. Your score means you're slightly better than the average at reading expressions. And research suggests that people can improve their emotion recognition skills with practice. So keep an eye out for our forthcoming empathy training tool, designed to boost your emotional intelligence. Sign upfor our e-newsletter for updates on it.
Drilling Engineering
Class 8
1
Casing
• What is casing?
• Pipe that is API certified for its specific application
• Why is casing set?
• Zonal Isolation when cemented in place
• Casing point selection
• Regulations
• Area Geology
• Formation Pressures
• As the operator, who decides on casing points?
2
Casing
• API casing is available in standard sizes from 4-1/2” to 20” OD
• Usually steel but can be aluminum, fiberglass, stainless steel,
plastic, titanium etc.
• One piece of casing pipe is referred to as a “joint” of casing
• Casing length is dependent on the “range” of pipe
• Range-1: 18-22ft
• Range-2: 27-30ft
• Range-3: 38-45ft
• Casing Threads are defined by the coupling type
• API Threads
• LTC: Long thread coupling
• STC: Short thread coupling
• BTC: Buttress thread coupling
• Semi & Premium Threads
• See VAM Presentation
3
Casing
• Casing Components
• Casing
• Size, Weight, Grade, Threads
• 9-5/8" 53.5# P-110 LTC Rg 3
• See Casing Data Chart
• What is Drift Diameter?
• Pup Joints
• Float Collars
• Float Shoe
• Guide Shoe
• Centralizers
• Baskets
• Scratchers/Scrapers
4
Casing
• Running Casing
• Bales/Elevators
• Power Tongs
• Torque Turn
• Calculate weight and Hookload HL
• Calculate collapse, how often should you fill the pipe?
• Is the pipe taking the proper amount of fluid to fill? CSGcap
• Is the proper amount of fluid coming back to the pits as the
casing is run in the hole? CSGcap & CSGdisp
• Once casing is landed, circulated mud. Calculate B/U
5
Casing
• Centralization
• Vertical Wells
• Never truly vertical, usually spiral
• Typically use bow spring type centralizers
• There are state regulations on centralizer placement
• The shoe is very important to be centralized
• Horizontal Wells
• Balance between too many and not enough centralizers
• Many types: rigid, floating, bow spring, bladed, spiral bladed, etc.
• Centralizer design software can model the well as drilled and suggest
centralizer placement
• High dogleg areas need more frequent centralizers to obtain
sufficient standoff
6
Casing
• Stand-off
• Pipe Stand-off is a major contributor to hole cleaning, mud
removal, and cement quality.
• % 𝑆𝑡𝑎𝑛𝑑𝑜𝑓𝑓 = ൗ𝑊𝑛 𝑅2−𝑅1 ∗ 100%
7
Casing
• Stand-off
• The Stand-off formula results a percentage, where 0% represents
the pipe in contact with the wellbore wall. 100% represents the
pipe is perfectly centered in the well.
• When the pipe is not centered, the wider portions will promote
flow due to less resistance. There can be pockets of cuttings or
mud in the tighter areas causing
Your Score 1420Not bad. Your score means youre slightly bette.docx
1. Your Score: 14/20
Not bad. Your score means you're slightly better than the
average at reading expressions. And research suggests that
people can improve their emotion recognition skills with
practice. So keep an eye out for our forthcoming empathy
training tool, designed to boost your emotional
intelligence. Sign upfor our e-newsletter for updates on it.
Drilling Engineering
Class 8
1
Casing
• What is casing?
• Pipe that is API certified for its specific application
• Why is casing set?
• Zonal Isolation when cemented in place
• Casing point selection
• Regulations
• Area Geology
2. • Formation Pressures
• As the operator, who decides on casing points?
2
Casing
• API casing is available in standard sizes from 4-1/2” to 20”
OD
• Usually steel but can be aluminum, fiberglass, stainless steel,
plastic, titanium etc.
• One piece of casing pipe is referred to as a “joint” of casing
• Casing length is dependent on the “range” of pipe
• Range-1: 18-22ft
• Range-2: 27-30ft
• Range-3: 38-45ft
• Casing Threads are defined by the coupling type
• API Threads
• LTC: Long thread coupling
• STC: Short thread coupling
• BTC: Buttress thread coupling
• Semi & Premium Threads
4. Casing
• Running Casing
• Bales/Elevators
• Power Tongs
• Torque Turn
• Calculate weight and Hookload HL
• Calculate collapse, how often should you fill the pipe?
• Is the pipe taking the proper amount of fluid to fill? CSGcap
• Is the proper amount of fluid coming back to the pits as the
casing is run in the hole? CSGcap & CSGdisp
• Once casing is landed, circulated mud. Calculate B/U
5
Casing
• Centralization
• Vertical Wells
• Never truly vertical, usually spiral
• Typically use bow spring type centralizers
• There are state regulations on centralizer placement
5. • The shoe is very important to be centralized
• Horizontal Wells
• Balance between too many and not enough centralizers
• Many types: rigid, floating, bow spring, bladed, spiral bladed,
etc.
• Centralizer design software can model the well as drilled and
suggest
centralizer placement
• High dogleg areas need more frequent centralizers to obtain
sufficient standoff
6
Casing
• Stand-off
• Pipe Stand-off is a major contributor to hole cleaning, mud
removal, and cement quality.
• % �������� = ��� �2−�1 ∗ 100%
7
Casing
• Stand-off
6. • The Stand-off formula results a percentage, where 0%
represents
the pipe in contact with the wellbore wall. 100% represents the
pipe is perfectly centered in the well.
• When the pipe is not centered, the wider portions will promote
flow due to less resistance. There can be pockets of cuttings or
mud in the tighter areas causing contamination to cement.
• Modeling software can analyze the As Drilled deviation
surveys
and generate a casing centralization plan with the casing’s
properties.
• 100% standoff is desirable but not realistic
• Industry minimum standard is 67% over the entire well
8
Casing
• Casing Centralizers
• Casing Baskets
• For lost circ zones
• Scratchers
• For mud cake removal
• Float/Guide Shoe
7. • Float Shoe will guide and has a one way valve
• Guide Shoe will guide the casing string down
the well
9
Running Casing
• Manual Tongs were commonly used, but few are used today.
• Power Tongs are used to make up (torque) casing joints
10
Running Casing
11
Running Casing
• Casing Running/Rotating Tool (CRT)
• Commonly used in ERD wells
• Used to rotate the casing string to achieve further
depths in the lateral section
• Allows the rig to pump fluid and circulate the
8. casing
• The combination of rotating and circulating
greatly reduces friction
• Static friction is overcome- Kinetic friction is lower
• The fluid gel strengths are broken down due to
movement
• Show Tesco video 12
Casing Connections
• API Connections
• First developed thread connections
• Cheap, easy to machine, designed to seal liquids
• LTC, STC, & BTC
• Weakest point in the casing string
• Premium Connections
• Developed after years of API thread failures
• Connections are stronger than pipe body
• Designed to seal liquid & gas
• Very expensive
• Semi-Premium Connections
• Developed most recently bc ‘Premium’ is so expensive
• Much stronger and more reliable than API connections
• Much cheaper than Premium
• Designed for liquids and limited gas
• See Vallourec & VAM Presentation
13
9. Cement
• Why cement?
• Zonal Isolation
• Isolation for completions frac stages
• Goals
• Protect ground water
• Prevent gas migration
• Stimulate more reservoir
• Protect casing from corrosion
• Increase life of well
• Two Types of Cementing Techniques
• Grouting- Utilizing gravity to pour cement from surface down
the
annulus
• Displacement- Pumping cement down the inside of casing and
using
a plug to push cement into the annulus from the bottom of the
well
to surface
14
10. Cement
• What is considered a good cement
job?
• Poor isolation is contributed by:
• Channeling
• Micro annulus
• Mud contaminated cement
• In horizontal and deviated wells:
• Mud removal is the most difficult
factor to overcome to achieve a
good cement bond
15
Cement
• How to improve the quality of the cement job
• Casing movement
• Casing centralization
• Hole and mud conditioning
• Mud properties
11. • Effective spacers
• Fluid velocity while pumping
• Wiper plugs
• Quality of shoe- single or double floats
• Circulating after casing is landed
• Lowers the viscosity, PV, the fluids resistance to flow
• Lower MW if at all possible
• Clean wellbore
• Calculate B/U
16
Cement
• Casing Movement
• Requires special equipment
• CRT with rotating cement head
• Pipe reciprocation/rotation
• At least one should be practiced if possible
• Energy is needed to break-up the gelled mud
12. • Mechanical interaction between the pipe and wellbore
• Changes the flow paths
• Monitor Torque and Drag while moving pipe
• Casing Centralization
• Enhances mud removal thus better cement bonds
• Wider annulus promotes flow 17
Cement
• Cement Blend and Requirements
• State regulations specify the type and properties of cement to
be
used
• Typically require Class A or H cement to be used
• Compressive strength of 500psi before any disturbance of the
casing, commonly 8-12hrs: time is crucial in operations
• Compressive strength of 1250psi in 72hrs
• Limited use of Calcium (CaCl or KCl) in blends (Disturb
surface
water)
• Thickening time of gels
• Little to zero free water
13. 18
Cement
• All cement blends are lab tested and come with quality reports
• Cement should be tested in the lab to mimic field conditions
• Water temperature- how does this effect cement?
• Formation temperature
• Quality of water used; take samples from location
• How do Chlorides effect cement? (brine, saltwater)
• Pumps times should be calculated based on volumes and pump
truck output
• We want the cement to thicken quickly to minimize waiting
time,
but we need it to remain “pump-able” until the job is complete
plus
a safety factor (70 bc time)
• Two stage cement jobs (lead & tail) can help reduce ECD and
lower
costs
• See example Lab Test Results & Cement Additives on
ecampus
19
14. Cement Procedures
1. Once the casing is landed, the driller will begin circulating
the
well with mud while monitoring TQ/Drag. Pump highest flow
rate possible through the shoe, with at least several B/U.
a) The mud engineer will monitor mud properties. Attempt to
lower PV and MW if at all possible. Why?
b) Derrickman will monitor the shakers for cuttings/debris
return
and notify driller of anything abnormal.
c) Floor hands/Motorman will rig down the power tongs and
clean
the rig floor.
2. While circulating, the cement crew will stage their trucks and
equipment, plumb into water tanks and cement silos, then
begin to batch mix the spacer.
20
Cement Procedures
3. Next step is to hold a cement job safety meeting
a) Communicate the plan/procedure to everyone on location
b) Define each persons roles/responsibilities
c) Talk through pump schedule going over calculations with
cement supervisor
15. 4. Stop circulating, rig up cement head equipment, and plumb
well into cement
pump truck
5. Cement crew will fill lines with water and pressure test
equipment
6. Begin pumping following a pump schedule
c) Spacer with Chemical Wash
d) Lead Cement Slurry
e) Tail Cement Slurry (if two stage)
f) Drop wiper plug and displace with water
g) Slow down the pump rate as plug approaches shoe
h) Land the plug with landing pressure
i) “Bump” the plug with ~500psi over landing pressure
j) Check that the floats hold: release pressure and measure
water returns. Should
get no more than a few bbls back
k) Bleed pressure to zero and wait on cement, WOC 21
Cement
• Spacer- A liquid (typically water &
Barite), weighted heavier & more
viscous then the circulating mud, that
pushes the mud out of the well ahead
of the cement. In OBM systems it will
help water wet the casing & formation
and enhance the cement bond.
Recommended to have 10min contact
time or 1,000ft of coverage.
16. • Wash- A low dense liquid chemical
pumped to break up mud cake off the
wellbore and treat the formation for a
better cement bond. 22
Cement Calculations
• Converting cement slurry volume to sacks of cement
• Cement blends will have a slurry yield (given)
#������ =
����(����) ∗ 5.6146(
��3
���
)
������ ����� (
��3
����
)
• Cylindrical Volume
� ���� =
�2 ��
1029.4
∗ �(��)
23
17. Cement Calculations
• Annular Cylindrical Volume
� ���� =
��2 �� − ��2(��)
1029.4
∗ �(��)
• Lifting force on the casing
�� = ���� ∗ � ∗ �� − (�� ∗ �)
Where, �� is the net lifting force in lbs: denote downward as
positive
���� is the air weight of casing in lbs/ft, D is the casing set
depth in
ft, BF is buoyancy factor, �� is the pressure required to land
the wiper
plug at the shoe in psi, A is the cross sectional area of the shoe
in
inches. 24
Cement Calculations
• Example: A. Calculate how many sacks of cement is required
for
the single stage cement job below. Assume perfect hole (no
18. excess), and cement to surface
20” 94ppf J-55 STC Rg2 casing is previously set at 800’
12-1/4” hole TD= 3500’
9-5/8”, 36#/ft, J-55 Casing run to 3450’
Yield: 1.2 cu.ft/sk; 8.5gal H2O per sack for 14ppg slurry
25
Cement Calculations
• Example cont’d
B. How many sacks of cement are needed if we pumped 30%
excess in the open hole section?
C. How many bbls of water is needed to mix the slurry (with
30%
excess OH) and to displace the wiper plug to the shoe?
D. What will be the pressure needed to land the wiper plug,
ignoring friction?
E. How much pressure is needed to hold the cement in place if
the float shoe happened to fail?
F. Given the floats hold, what is the lifting force on the casing?
26
19. Cement Plugs
• Plugs can be “spotted” for several reasons
• Abandon a well
• Artificial KOP
• Lost tools downhole
• Directional driller is off plan and can’t achieve doglegs to
recover
• Pilot well was vertically logged deep beyond producing zone
• Class H cement is designed for plugs
• High compressive strength
• Plugs can be set in air or fluid filled hole
27
PNGE 310: Drilling Engineering; Project #2 - Summer 2019
Due Date: 7/25/19
In groups of 2, you will design a casing and cementing plan for
a horizontal shale gas well. The proposed well
is located just outside of Morgantown, WV and has a planned
TD of 18,500ft MD (7,420ft TVD) in the Lower
20. Marcellus Shale. Utilize the provided geologic prognosis and
the WV DEP regulations on “Casing and
Cementing Standards” on eCampus to justify the setting depths
of each string of casing. The regulations will
also provide guidance on cementing standards such as top of
cement for each string. All casing should be
new, steel, and API certified. You are allowed to combine the
coal casing string and the freshwater casing
string in this area.
Casing:
Your design should include the following casing strings for the
proposed well: conductor, surface,
intermediate, and production. Specify the hole size that will be
drilled and to what depth. There should be at
least 1.5 inches of cement around the casing in the annular on
all sides (per regulations) and sufficient rat hole
below the casing (30-50ft). Provide the size & type of casing
you chose and to what depth it should be set.
The drift diameter must be larger than the next section bit size.
Provide any details of auxiliary equipment
utilized such as a float shoe or centralizers and their placement.
Be sure to check for casing failure against
21. burst & collapse during cementing, and consider the lifting
force on the casing after the cement is pumped.
The production casing will be perforated in the lateral and the
Lower Marcellus formation will be stimulated
(frac’d). The pressure gradient of the Marcellus is estimated at
0.86psi/ft. The fracture gradient is measured
to be 1.12psi/ft on an offset well. The burst rating of the
production casing must support at least 20% above
the anticipated fracture pressure.
Cement:
You should provide a plan for cementing each string of casing.
The plan should include the slurry volumes,
displacement volumes, total water required on site, the number
of sacks of cement, and how many hours you
will wait on the cement to cure (WOC) for each string of casing.
The conductor may be grouted, but all other
strings must utilize the displacement method.
Well Construction Diagram
23. Shallow oil/gas & saltwater
Geologic Prognosis
WELL: WVU#1 COUNTY & STATE: Monongalia County
LOCATION: Pad Elevation: 1085
Top Depth from
Ground Elevation
(TVD)
Formation Possible Show Coal Seam
Thickness (FEET)
Minable Coal
Seam
General Rock Type
0- 80
Zones of fill and shallow water
FRESH
WATER
399 Waynesburg #2 Seam
24. 0.95 NO Coal
404 Waynesburg #1 Seam
FRESH
WATER
3.24 YES Coal
665 Sewickley Coal Seam
FRESH
WATER
6.18 YES Coal
753 Roof Coal Zone Seam
FRESH
WATER
4.20 YES Coal
758 Pittsburgh Coal Seam
FRESH
WATER
7.34 YES Coal
1598 Clarion
Sandstone
2320 Big Lime
Limestone
25. 2411 Big Injun Top
SALT WATER Sandstone
2651 Big Injun Base
Grey Shale
3097 50 Foot
OIL & GAS Sandstone
3120 Nineveh Sand
OIL & GAS Sandstone
3233 Gordon
GAS / WATER Sandstone
3362 Fourth
GAS / WATER Sandstone
3407 Fifth
SALT WATER Sandstone
4861 Elk
Siltstone
6837 Rhinestreet
Grey Shale
7197 Burkett
Black Shale
7222 Tully
Limestone
7261 Hamilton
Grey Shale
26. 7364 Upper Marcellus
GAS Black Shale
7400 Purcell
Limestone
7404 Middle Marcellus
GAS Black Shale
7416 Cherry Valley
Limestone
7418 Lower Marcellus
GAS Black Shale
7435 Onondaga
Limestone
O.D. Nominal Grade Collapse Body Wall I.D. Drift Diameter
(inch) Weight Pressure Yield (inch) (inch)
T & C (psi) 1000 lbs
lbs/ft PE STC LTC BTC STC LTC BTC API LSS
4.500 9.50 J-55 3310 4380 4380 101 152 0.205 4.090 3.965
4.500 9.50 K-55 3310 4380 4380 112 152 0.205 4.090 3.965
4.500 9.50 LS-65 3600 5180 5180 135 180 0.205 4.090 3.965
4.500 10.50 J-55 4010 4790 4790 4790 132 203 166 0.224 4.052