drilling and completions

Drilling and Completions

Faculty of Chemical Engineering

CGE 416Introduction to

Petroleum Technology



Fundamental of drilling engineeringDrilling preliminaries & overview of drilling systemsDrilling problems & drilling techniquesTesting a well and well completion



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



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



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



Rig types and rig selection Types of rig can be contracted for offshore drilling



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



Rig types and rig selection Jack-up



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




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



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



Rig types and rig selection Drillship



Drilling system and equipment Basic drilling system for

both onshore and offshore will be the rotary rig



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



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.

drilling and completions

Documents

rig selectiontypes of

completions rig types

rig selectionthe type

penetration rig

drilling location3

objective of drilling

rig selectionjackupjack

day night rig crewdriller