Chapter 4 Flashcards
Define drilling
The operation to drill a hole in the earth in order to produce
oil, gas, water or to dispose liquid wastes or greenhouse gases
safely and economically is called drilling.
What are the 11 steps to follow before drilling a well?
- Gather seismic, log, and geological data,
- Conduct reserve estimation,
- Determine and highlight the well location on the map,
- Start the drilling if reserve estimates show payout,
- Obtain permits from conservation/ national authorities and
environmental regulatory bodies, - Prepare drilling and completion program,
- Based on the drilling program, ask for bids on footage, day
work, or combination from selected drilling contractors. If
required, modify program to fit the selected contractor equipment - Prepare the required infrastructure such as constructing road,
platforms and other marine equipment necessary for access
to site. - Gather all personnel for meeting prior to starting drilling.
- Final decisions on drilling plan and if necessary, further
modify program. - Drill the well.
What are the 6 types of wells
Wildcat wells, Exploration wells, appraisal wells, production wells, abandoned wells, injection wells
What are wildcat wells
drilled outside of and not in the
vicinity of known oil or gas fields.
What are exploration wells
drilled purely for exploratory
(information gathering) purposes in a new area
What are appraisal wells
used to assess characteristics (such as
flow rate) of a proven hydrocarbon accumulation
What are production wells
drilled primarily for producing oil or
gas, once the producing structure and characteristics are
determined
what are abandoned wells
wells permanently plugged in the
drilling phase for technical reasons.
What are injection wells
wells used to inject water or gas to
maintain the pressure or to dispose the produced water for
the case of water injectors and dispose greenhouse gases for
the case of gas injectors
Where and when was the earliest well drilled
China in 347AD. Th40 meters
Where and when was the first commercial land well drilled and shore well drilled in north America
oil springs Ontario in 1858
Summerland oil field on the California coast in 1896
What are the two types of conventional rotary drilling rigs
rotary table and top drive
Define rotary table
The source of the rotation is provided by a
square or hexagonal pipe, named Kelly, at the floor level.
The rotation from Kelly will provide clockwise rotation
for the rotary table and the drill string.
Define top drive
The source of rotation is provided with a
powerful motor at the top of the drill string that moves in a
track along the drill string. Top drives are capable of
tripping drill stands, which will result in faster drilling
operation. However, these rigs are more expensive
compared to rotary tables.
Two types of mobile rigs for land
Portable mast and Jack knife
4 types of floating drilling rigs (marine)
Drill ships, semisubmersible, jack up, fixed platform
4 types of drilling rigs based on the depth if drilling
Light duty rigs - 3000-5000 feet
medium duty rigs - 4000-10000 feet
heavy duty rigs - 12000-16000 feet
ultra hevy duty rigs - 18000-25000 feet
How many people are directly or indirectly involved in a drilling operation
75
Who are the main 8 people involved in the drilling crew
Company man, tool pusher, roughneck, roustabout, driller, motorman, derrickman
What does the company man do
Is the representative of the operating company and he/she is sometimes called
drill site supervisor or well site manager.
What does the tool pusher do
For the drilling rigs on land, tool pusher is responsible for all the drilling
operations, but on offshore drilling rigs tool pushers are department heads for
different departments
What does the roughneck do
Their main duty on the drill floor is to connecting drill pipes. They might be
involved other work around the rig.
What does the roustabout do
They are in charge of duties on the rig which require little training like cleaning
and painting. After gaining experience roustabouts may become roughneck.
What does the driller do
He is responsible for the drilling machinery during drilling.
What does the motorman do
His responsibility is to maintain of various engines, water
pumps, water lines, steam lines, boilers and various other
machinery on the rig on a daily basis.
What does the derrickman do
He is responsible to check on the drilling mud in the drilling
pits. He is also responsible to help during the tripping
What are the 5 major drilling components of a drilling rig
Power system, Hoisting system Rotary system, Circulating system, Well control and monitoring system
Components of the hoisting system
Derrick(steel tower)
Monkey board(platform on the derrick which the derrick man works on during the tripping)
Crown block(assembly at the top of the derrick which includes sheaves and pulleys)
travelling block(assembly of sheaves and pulleys which move up and down the derrick. lifts things in and out of the well)
Drawworks(power system to a hoisting capability to carry out the drilling
Equation for compressive load the Derrick can handle
Wd = (n+2/n)W
Wd - compressive load, lb
n = number of lines through the travelling block
W - hook load, lb
Equation for the drawworks
HP = (Wvh / 33000) (1/e)
W - hook load, lb
vh - hoisting velocity of travelling block, ft/min
e - hook to drawback efficiency
Components of the rotating system
Swivel(supports the drill strings weight and allows it to rotate)
Kelly(square hexagonal shape pipe attached to the swivel from top and fits at bottom in the rotary table)
Rotary table(provides
a clockwise rotational force to the drill string to carry out the drilling operation.)
Components of the circulating system
Mud tanks(square open-top
containers made of steel to store
the drilling fluid during the
drilling operation.)
Shale shaker (remove
the coarse cuttings from the
drilling fluid by means of
vibration and screening.)
Desander-Desilter (separate sand-size
particles from the drilling mud)
Mud pump (reciprocating pump that is
responsible for creating the
circulation in the entire system.)
Stand pump ( metal pipe is used to conduct
the drilling mud from the mud
tanks to the kelly hose)
What is the well control and monitoring system
BOP
They are specialized valves which
control the excess pressure and flow
from the bottomhole formation. If
the excess flow from the formation
is not controlled, a dangerous
condition called blowout may
happen.
List the type of rams in the BOP
Pipe Rams, Blind rams, Blind shear rams
What do pipe rams do
close around a drill pipe, restricting flow in the annulus
(ring-shaped space between concentric objects) between the outside of
the drill pipe and the wellbore, but do not obstruct flow within the drill
pipe.
What do the blind rams do
which have no openings for tubing, can close off the well
when the well does not contain a drill string or other tubing, and seal it.
What do the blind shear rams do
cut through the drill string as the rams close
off the well and shut the well. Using these rams should be the last
option as it will cut through the whole drill string to shut the well.
What are the major applications of well completion
- Provides the path for the injection or production of fluid
by connecting the reservoir to the surface. - Protect the integrity of the wellbore, especially in
unconsolidated formations - Provide the space and structure for well stimulation
treatments - Isolate the producing zone from other zones
- Provide a conduit to carry out the well testing
What are the three different types of well completion
open hole completion
Linear completion
Perforated casing completion
What is the difference between single completion and multiple completion for wells
single completion is perforated in one area of rock
Multiple completion is perforated in multiple layers of rocks, with different structures of tubing
Define wat casing is
Hollow steel pipes with different diameters which are installed in
the well with following major applications
List the reasons casing is important to use
To prevent the hole from caving in
* To prevent contamination of underground fresh water zones
* To prevent water migration to producing formation
* To limit production to the wellbore
* To control pressures during drilling
* To provide an acceptable environment for subsurface equipment
in producing wells
What are the 6 types of casing and the order they go in from widest to skinniest
Structural casing
conductor string
surface pipe
intermediate string
production liner
Describe the usefulness of Conductor casing
- Prevents the corrosion of subsequent casings.
- Used for installing director system on it.
- Prevent eroding surface sediments and rig foundation by
circulating the drilling fluid to the shale shaker.
Describe the usefulness of surface casing
- Controls caving and washing out of poorly consolidated or
unconsolidated shallow beds. - Used for installing BOP on it.
- Prevents the contamination of underground fresh water zone
which might be caused by drilling fluid mud, oil or gas and
or salt water from lower zone
Describe the usefulness of intermediate casing
The number of intermediated casings to be used depends on well
depth and geology in specific area.
Main application: To isolate troublesome zones which:
- Contain abnormal pressure fluids, protect formation below
the surface casing from higher pressure which might be
inserted by mud.
- Contaminate drilling fluid.
- Might result in pipe sticking and excessive hole enlargement
during drilling operation.
Describe the usefulness of production casing
It is set through productive interval to the surface in order to:
1. Isolate the pay zone.
2. Can be used to produce fluid instead of producing from
tubing.
Describe the usefulness of the production liner
It is set to the productive zone but it is not connected to the
surface. It functions like production casing but compared to the
production casing it is lower in cost
What are the useful applications of cementing
- Support and protect the casing in the wellbore.
- Prevent the movement of fluid through the annular space
outside the casing - Prevent the movement of fluid into vugular or fractured
formations - Sidetracking
- Plug and shut down an abandoned well or a portion of a well
Define perforation
It is a process of connecting the wellbore to the adjacent
reservoir by initiating holes through the casing and cementing
into the producing zone.
What are approaches for conducting perforations
✓ laser
✓ hydraulic punches
✓ mechanical punches
✓ water jet
✓ combination bullet/jet guns
✓ electric arc perforating
Define formation damage
the reduction in production from reservoir
caused by invasion of wellbore fluids used during drilling,
completion and workover operations. The damaged zone
which is in the vicinity of the wellbore has a reduced
permeability.
How to measure the formation damage?
With the Skin factor and is represented with S.
The factor is positive for the damaged zones
Causes of formation damage
✓Drilling
✓Workover
✓Completion
✓Production
✓Stimulation
✓Secondary oil recovery
✓Enhanced oil recovery (EOR)
What is stimulation
Opening the new channels in the reservoir rock for the better
flow of hydrocarbons into the well is called stimulation.
What are the 3 main approaches for conducting stimulation
✓ Using explosives
✓ Acidizing
✓Hydraulic fracturing
What does it mean to use acidizing when conducting stimulation?
Acidizing is normally carried out at the final stage of
production when the rate of production is not economical any
more. Highly diluted hydrochloric or hydrofluoric acids
(concentrations of 1 to 15%) are injected into the formation.
These acids are corrosive to casing, therefore the used acid
and other possible sediments will be pumped out from the
wellbore in a process called backflush after acidizing job.
