Introduction-to-Petroleum-Eng-Part-2.pdf

Introduction to Petroleum Engineering
Drilling Rig types, main components

 Extraction of oil and gas from a subsurface formation requires access to the
resource. Drilling is one step in that direction. So, Reservoir fluids are
accessed by drilling a well and then preparing the well for the production
or injection of fluids.
 Expenditure for drilling represents a large fraction of the total project’s
capital expenditure (CAPEX) (typically 20–60%), therefore an understanding
of the techniques, equipment and cost of drilling is important.
 Rig: the derrick, drawworks, rotary table and all associated equipment
required to drill a well.

 Usually, wells are drilled with one, or a combination, of the following
objectives:
 to gather information
 to produce hydrocarbons
 to inject gas or water to maintain reservoir pressure or sweep out oil
 to dispose of water, drill cuttings or CO2 (sequestration)

 First commercial oil well
 The first commercial oil well in Titusville, Pennsylvania, was drilled with
a cable tool rig.
 Cable tool rigs lift and lower a bit to pound a hole in rock formations.
 As needed, pounding would be stopped so water and debris could be
bailed from the hole with a “bailer” on a cable.
 And then the pounding resumed.
 Cable tool rigs could routinely drill from 25 ft per day up to 60 ft per
day.
 Cable tool drilling, which is also known as percussion drilling, was used
for all US fields in the 1800s.
but this method is slow
 It does not prevent unstable rock from collapsing into the wellbore.
 It does not effectively control subsurface pressure.
 Consequently, the uncontrolled production of fluids, known as a blowout, was
common.

1. Onshore rigs can either be
 moved in pieces and assembled
on location.
 or mounted on a truck.
 Rotary drilling was introduced in the
late nineteenth century and became
the primary drilling method by the
early twentieth century.

 Rotary drilling was introduced in the late nineteenth century and became
the primary drilling method by the early twentieth century.
Jack-up rig
Semi-submersible rig Drill ship
2. Offshore rigs

 Rotary drilling was introduced in the late nineteenth century and became
the primary drilling method by the early twentieth century.
Offshore rig types

 Offshore rig types

 The size of a rotary rig depends on
 The weight.
 And power requirements associated with the depth of the well. A
larger rig is used for a deeper well.
 Offshore rigs come in different forms depending on water depth, for
example.
 Barges can be used for shallow water or swamps.
 Jack-ups can be used in water that is relatively shallow to a few
hundred feet of water.
 Semisubmersibles are used in a couple thousand feet of water.
 Drillships are used in several thousand feet of water.

 Rig Selection: The type of rig which will be selected depends upon a
number of parameters, in particular:
 Cost and availability.
 Water depth of location (offshore).
 Mobility/transportability (onshore).
 Depth of target zone and expected formation pressures.
 Prevailing weather/metocean conditions in the area of operation.
 Experience of the drilling crew (in particular the safety record!).

 A rotary rig has several systems:
1. A power system.
2. A hoisting system to raise and
lower the drill pipe.
3. A circulation system to circulate
drilling fluid or “mud”.
4. A rotation system to rotate the
drill pipe.
5. In addition, a rotary rig has a
system for controlling the well
during emergencies.

Drill String, main components

Illustration of the
hoisting system
 A hoisting system
The hoisting system is used
mostly to move the strings of
drill pipe or casing up and down
in the wellbore.

Derrick with pipe
in rack
 A hoisting system
To repair or replace parts of the
drill string, the crew must hoist,
or “trip,” it out of
the hole. During a trip, stands of
pipe are stored between the
derrick floor and the monkey
board. The monkey board is
where the derrickhand
is stationed to guide the pipe. A
stand of pipe is two or three pipe
joints that are screwed together.

The
drill
string
(schematic)
 The drill string consists of:
 Drill pipes
 Drill collars
 Drill bit
 And optional attachments
 Drill stem: used in place of drillstring in some
locations. Describes all the drilling components
from the swivel down to the bit.

 Drill pipe: is the major component of the drill string, which
forms the upper part of the drill string. It is a seamless pipe
which is used to rotate the bit and circulate the drilling fluid.
 Drill collars: are heavy-walled drill pipes that
 place weight on the drill bit during actual drilling.
 keep the drill pipe in tension to prevent bending
and buckling of the drill pipe.
Drill pipe and collars are rated by
 Size (outer diameter).
 Weight per unit of length.
 Grade (steel material and manufacturing process).
 Connections.

 Drill bit:
the cutting element at the
bottom of the drillstring, used
to grind, break, or shear the
rock at the bottom of the well.
Rotary bits are either
 Roller‐cone.
 Or drag bits.
Drag
(PDC)
bit
Roller
cone
bit

 Drill bit:
Materials used for cutting surfaces
of bits depend on what type of
formation the drill bit will
encounter. 1. Roller‐cone bits can
have
 Steel teeth
(softer formations).
 Tungsten carbide buttons
(harder formations).
Roller cone (tricone) bit

Polycrystalline Diamond Compact
(PDC) bit
 Drill bit:
Materials used for cutting surfaces of
bits depend on what type of formation
the drill bit will encounter. 2. drag bits
can have
 PDC discs bonded to tungsten
carbide posts mounted on the
surface of a bit. PDC bits are good
for drilling hard formations.
 Diamond-impregnated bits have
whole diamonds bonded to the
surface of a bit. These bits can be
used for the hardest formations.

Stabilizers Jars
 And optional attachments: may include
Shock subs, etc.

Introduction-to-Petroleum-Eng-Part-2.pdf

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