Drilling and Completions
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Transcript of Drilling and Completions
Drilling and Completions
Faculty of Chemical Engineering
CGE 416Introduction to
Petroleum Technology
Faculty of Chemical Engineering
Drilling and Completions
Fundamental of drilling engineeringDrilling preliminaries & overview of drilling systemsDrilling problems & drilling techniquesTesting a well and well completion
Faculty of Chemical Engineering
Drilling and Completions
Once geologist and geophysicist have found a promising geological structure and location to drill for commercial oil and gas it is time to go ahead with drilling
The objective of drilling to bore a hole (the well bore)• Until penetrate a target rock formation – that has been
identified by the geologists and geophysicists as having the potential to contain commercial hydrocarbons
The formations through which will be drilling may be porous and permeable, and may contain fluids (oil ,water or natural gas) at very high pressures
Faculty of Chemical Engineering
Drilling and Completions
Appropriate precautions should be taken to avoid blowout – when the fluid spew violently out of the hole which is extremely dangerous as well as damaging to the environment
These blowout frequently:• Caught fire• Destroyed the rig
Technology of today’s drilling industry is focused on drilling safely and economically into the pressurized underground formations without allowing any uncontrolled flow of fluids out of the well
CLASIFICATION OF WELL TYPES
WHY DO WE DRILL WELL
Rig Establishment & Reporting Lines
Service Companies
SHORE BASED
RIG BASED
Operating Company
MudEngineer
MudLoggers
Cementer
ElectricLoggers
WellheadSpecialist
DirectionalEngineer
CoringEngineers
SeniorGeologist
WellsiteGeologist
DrillingSuperintendent
DrillingEngineer
Senior DrillingSupervisor
Mechanics (2)Motormen (2)Electrician (1)
SubseaEngineers (2)
C.Room Ops (2)Crane Ops (2)Deck Crew (6)
RadioOps (2)
Day & Night Rig CrewDriller (2)
Ass driller (2)Derrickmen (2)Roughnecks (6)
ChiefEngineer Medic Night
ToolpusherBarge
Captain
SeniorToolpusher
DrillingSuperintendent
Drilling Contractor
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection The type of rig which will be selected depends upon a number
of parameters:• Water depth of location (offshore)• Mobility/transportability (onshore)• Depth of target zone and expected formation pressures• Prevailing weather conditions in the area of operation• Safety – drilling crew
Onshore operations – various types of land rigs are available, ranging from truck mounted light rigs up to heavy land rigs
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Types of rig can be contracted for offshore drilling
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Jack-up
Jack-up rigs are towed over the drilling location 3@4 legs of the rig are lowered onto the sea-bed After some penetration rig will lift itself to a determined
operating height above sea level Jack-up rigs are operational in water depths up to about
650ft and as shallow as 15ft Most common rig type
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Jack-up
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Semi-submersible
Floating type of rig Structure is supported by large pontoons which are
ballasted with water to provide the required stability and height
During rig moves, only pontoons are submerged At drillsite, the pontoons are partially flooded so that the
rig rides deep in the water providing a stable drilling platform
Rig is held in position by anchors and mooring lines or dynamically positioning system (DPS) by thrusters
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Semi-submersible
Large diameter steel pipe (riser) is connected to the sea-bed & serves as a conduit for the drill string
Often used in water depths too deep for jack-up Anchor handling and the length of the riser eventually
impose a limit on the operating depth Their stability makes them suitable vessel for hostile
offshore environments
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Semi-submersible
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Drillship
Drill ships are used in deep water and remote areas Vessels are equipped with a drilling unit positioned in the
middle of the ship Positioning is achieved dynamically by computer unit
positioned in the middle of the ship Positioning is achieved dynamically by computer controlled
thrusters Mobility – can easily move off to other location under
short notice, such as in areas with a high iceberg population
Faculty of Chemical Engineering
Drilling and Completions
Rig types and rig selection Drillship
Faculty of Chemical Engineering
Drilling and Completions
Drilling system and equipment Basic drilling system for
both onshore and offshore will be the rotary rig
Faculty of Chemical Engineering
Drilling and Completions
Drill bit Most frequently used bit types are the roller cone @ rock bit
and polycrystalline diamond cutter (PDC) bit On the rock bit, the three cones are rotated and the attached
teeth break the rock underneath into small chips – cuttings Cutting action is supported by powerful jets of drilling fluid
which are discharged under high pressure through nozzle located at the side of the bit
Faculty of Chemical Engineering
Drilling and Completions
Drill bit After some hours of drilling (between 5 and 25 hours
depending on the formation and bit type) – teeth become dull and the bearing wear out
PDC bit is fitted with industrial diamond cutters Being used widely due to better rate of penetration, longer life
and suitability for drilling with high revolutions per minute (rpm)
Bit type selection depends on the composition and hardness of the formation to be drilled and the planned drilling parameters
Exercise
• A drilling contractor wants to drill a well 2000 m underground offshore Pasir Puteh. The rig will stay 30 days at the site, and will start drilling at day 3 until day 27. 10 PDC bits are reserved for this operation, each 1 cost 20 k USD. The operating cost is 200k USD per day. Calculate the overall cost per foot for this drilling program.