Final Review (Casing to Well Control) Flashcards
name the 4 types of casing and their respective sizes
conductor (20”), surface (13 3/8”), intermediate (9 5/8”), production (7”)
what is the purpose of a liner
reduces cost by hanging the production casing (doesn’t extend the full hole length)
what are the 4 main selection criteria for casing?
- Casing Grade
- Casing Size
- Setting Depth
- Pore Pressure and Fracture Gradient
what are the 3 types of threads?
short rounded, buttress, extreme line
if a casing is grade J-55, what minimum pressure is it rated for?
55,000 psi
name 2 tests that can be performed on casing
LOT (Leak Off Test) confirms the strength of the cement bond around the casing shoe, and FIT (Formation Integrity Test) tests the strength of the shoe and formation
what are the 3 main functions of casing?
isolation, support, prevention
what are collapse conditions?
external pressure greater than internal
what condition has internal pressure greater than external?
burst conditions
what are the secondary forces on casing?
torque, buckling, bending, axial compression
what are the 3 casing failure mechanisms?
shear, collapse and corrosion
what are the 3 forces casing needs to be able to withstand?
burst, collapse, tension
what all factors into casing setting depth?
geological information
offset well data
hole section summaries from other wells
pore pressure and fracture gradient prognoses
how do you calculate a pressure gradient?
pressure/depth
what are the 4 pipe collapse calculations?
yield strength pressure
plastic pressure
transition pressure
elastic pressure
2 reasons why cement is crucial to any well
zonal isolation
well integrity
what is a common hole problem that occurs during cementing
channeling
what is the most popular cement?
Portland
what are the 5 physical properties of cement
- Slurry Density
- Yield
- Thickening Time
- Compressive Strength
- Additives
what is the difference between primary cement and secondary cement?
primary is the initial cement job and secondary is repair cement
what is the metric constant?
0.00981
what does cement physically do to the casing?
bonds it to the formation
what class of cement is most common for surface casing?
Class A or G
when is Class J cement most effective?
HPHT
what is shoe track?
the distance between the float collar and float shoe
during a cement job, what is the most common amount of excess used in calculations?
100% (multiply by 2 in calculations)
what are the 2 slurry properties?
specific gravity and absolute volume
what is ECD and ESD
Equivalent Circulating Density and Equivalent Static Density
where is the highest pressure drop in a drilling system?
the bit
what is one important function of drilling fluid?
counter subsurface formation pressure
what are the 3 situations when subsurface fluid pressures become critical?
static, circulating, and tripping
what are abnormal conditions for a water gradient?
> 0.5 psi/ft OR 11 kpa/m
what water gradient condition is = 0.5 psi/ft or 11 kpa/m
normal condition
what are subnormal conditions in psi/ft?
< 0.435 psi/ft (9 kpa/m)
list 3 of the 5 times when fluid is static
connection, prior to running casing, flow check, rig problems causing shutdown, and wireline operations