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
when is fluid in a dynamic condition?
when fluid and the drill string are in motion at the same time
where are the 4 points pressure losses occur?
surface, drill string, bit, annulus
name 3 companies with drilling software
Haliburton, Peloton, and Schlumberger
what does proper nozzle selection increase?
penetration rate (ROP)
what must be defined in order to optimize hydraulics?
- Penetration Rate
- Operating Cost
- Bit Wear
- Potential Hole Problems
- Fluid Transport Velocity/Carrying Capacity
what factors affect bit performance?
over balanced pressure, drill fluid properties, formation characteristics, WOB, rotary speed, bit design, hydraulic efficiency
4 factors involved in bit design?
teeth protrusion, tooth shape, number of teeth, and skew
what are the 3 most important bit optimization parameters?
flow rate (Q), pressure drop (P), and hydraulic horsepower (HIS)
what are 2 reasons for pulling a bit
cost rises, drop in ROP, excessive surface torque, and planned formation change
what are the 3 common hydraulic design parameters?
- Bit Nozzle Velocity
- Bit Hydraulic Horsepower
- Jet Impact Force
what does the symbol “Vn” stand for?
nozzle velocity
what is the imperial constant?
0.052
what are 5 of the 8 practical rig hydraulics?
Pressure Losses
Hydraulic Fundamentals (gel strength, mud weight, YP, viscosity, shear stress, PV, friction factor, Reynolds number)
Flow Regimes (turbulent, laminar, transitional)
Fluid Types (Newtonian, Non-Newtonian)
Rheological Models (Bingham Plastic (YP, PV), Power Law (n, K), Hershel Buckley (τ=τ_α+κ ∙ γ^n))
Practical Hydraulic Equations
Optimization of Bit Hydraulics
Mud Carrying Capacity
name 6 different types of electronic logs (17 different choices)
SP (Spontaneous Potential), Caliper, Cement Bond Log, Gamma Ray, Sonic, Neutron, Density, LWD (Logging While Drilling), MWD (Measurements While Drilling), VSD (Variable Speed Drive), FIT (Formation Integrity Test), RFIT (Repeated Formation Integrity Test), Porosity, DST (Drill Stem Test), IP (Initial Potential (done in cased hole before production)
what 2 times are involved in mud logging?
lag time and downhole circulation time
what is a kick?
an influx of unwanted fluids (gas) into the wellbore
where is formation pressure in regards to hydrostatic pressure
deeper
what makes up foam?
lamallea + gas bubbles
what are the 3 causes of a kick?
weight is less than the formation pressure, weight is significantly higher than the formation pressure (can fracture the formation), and mud loss
what does IFT stand for?
Interfail Tension
what is the critical mistake a driller can make?
not keeping the hole full while tripping in/out, swabbing the well while drilling
what is swabbing?
when the drill string is pulled out very fast and a vacuum is created, pulling formation fluids in the well bore
what are the 2 cases of abnormal pressure?
too high or too low
what is surge?
opposite of swabbing, mud is packed below the bit and causes a pressure increase
what is rotary torque?
the torque required to turn to drill string
what could indicate a possible kick?
abnormal pressure, increase in rotary toque, gas-cut mud, connection and trip gas, change in mud properties, increased flow rate, increased mud tank volume, reduction in pressure with an increase in pump speed, well flow with pumps off, and tripping
what is the BOP
blow out precentor, and SHOCKER!!!! it prevents blow outs
name the 3 types of rams on a BOP
blind rams (seal off hole when no pipe is in the hole), pipe rams (close on the pipe), shear rams (cut the pipe)
what do annular preventers do?
close around the pipe and seal off the annulus
what are the 2 drill string control methods
drill stem valves and floats
what is the purpose of the choke manifold and how does it control a kick
when a kick is encountered, flow is directed to the choke manifold by opening the HCR (Hydraulic Control Relief) valve. The choke manifold then controls the flow and pressure through a series of chokes and valves. Flow then goes through the degaser and desilter, then returning to the mud tanks.
what is the purpose of the mud gas seperator
to sperate gas from the mud after passing through the choke manifold
what is the purpose of the trip tank?
small tank used while tripping to accurately measure any mud loss or gains.
what are the 3 methods of killing a well?
Drillers method, Weight and Wait/Engineers, and Concurrent Method
describe Drillers Method and how many circulations are involved
2 complete circulations. First circulation flow is directed to the choke manifold, kick is pumped out of the well, and the second circulation pumps down kill weight mud to increase the hydrostatic pressure.
how does Weight and Wait/Engineers method work and how many circulations?
1 circulation. Kill weight mud is pumped into the hole at the same time as the kick is circulated out the annulus
how does concurrent method work?
well is shut in and kill weight mud is pumped downhole in increases of 10 ppt until the well is killed.
what do SICP, SIDPP, and MACP all stand for?
Shut-In Casing Pressure, Shut-In Drill Pipe Pressure, and Max Allowable Casing Pressure
what is critical to conventional drilling?
physical properties (viscosity etc). fluid is used as a medium to transport cuttings.
what is under balanced drillings most important parameter?
velocity
how do under balanced rigs work?
they use a very low mud weight drilling fluid, staying at or below formation pressure, which prevents formation damage.
what are 3 advantages of under balanced drilling?
- increased ROP
- better for environment
- improved hole cleaning
what are 2 disadvantages of under balanced drilling?
- no experts
- extreme lack of personnel
what do under balanced rigs look for?
they intentionally look for kicks
at what temperature will the compressive strength of all neat cured cements under pressure decrease?
93 degrees Celsius
what is the specific gravity of Portland cement?
3.10-3.25
why must a safety factor be added to cementing?
any slight miscalculation in the thickening time could lead to cement setting and drying inside the casing. Therefore you musty add a safety factor to the thickening time
what prevents cement from going back into the casing once passing through the float shoe?
the float collar
name the 3 ways of well evaluation
mud logging, coring, and wireline logging
why is it necessary to evaluate a well?
to prove hydrocarbons are there, to see if drilling was a success, and to see if the reserve is economical
name 2 reasons for running a LWD tool.
- to have real time data to make decisions
- un-invaded data is required of the formation fluids
what are 2 uses of the casing string?
prevent the hole from caving in and to isolate production to the well bore
when are collapse conditions most likely to occur?
during a cement squeeze job
when are burst conditions most present?
when cement is present above a below a lost circulation zone
