Introduction to Drilling for non-technical personnel

Introduction

This presentation is intended to give a general overview of the drilling industry

—Oil/Gas Reservoirs & Where to drill—Drilling—Different kinds of rigs—Who owns what at the rig site—Roles of personnel

Oil / gas (hydrocarbon) reservoirs

“Source rock”— organic rich

Covered over time Heat & pressure “rots”

the organic matter. “Fossil Fuel”

Oil, gas & water permeate upwards through the small gaps in between the rocks

“Cap rock or Trap” –impervious layer

Reservoir rock – Porous— Sandstone — Carbonates

Where to drill?

Historically – Wells drilled in the vicinity of oil seeps.

Today potential locations are identified using a combination of data:

- Surface outcrops of the same formation.

Where to drill?

Today potential locations are identified using a combination of data :- Seismic surveys carried out provide “underground

map” of where the oil / gas could be trapped.

- Sea- Air Gun- Hydrophone

- Land- Thumper Truck- Geophone

Where to drill?

Today potential locations are identified using a combination of data :

- Offset (nearby) well data

A

B

C

Drilling

Drill bit on the end of drill pipe is turned and drills the hole

As the hole is drilled deeper more drill pipe is screwed on at surface

At a certain depth the drill pipe is pulled out of the hole to run ‘casing’

Casing is pipe used to line and isolate the wellbore

Cement is pumped between the outside of the casing and the formation

A smaller drill bit (has to fit inside the casing) is then run and a smaller hole is drilled…

… and more casing run

Drilling - Mud

While drilling mud is pumped down the inside of the drill pipe

It comes out of nozzles in the drill bit and travels up around the outside of the drill pipe and back to the surface

The mud serves 3 main purposes— Keeps the drill bit cool— Lifts all of the rock that the drill bit has cut back to the

surface – “cleaning the hole”— Applies hydrostatic pressure on the rock to stop the hole

from falling in and preventing oil / gas coming into the hole

Directional Drilling

Not all wells are vertical - It is possible to drill wells directionally

Special tools are run that curve the wellbore The drill pipe is flexible enough so that it can

bend around the curve Why?

— Done in a controlled fashion to hit geological targets— Drill from different surface location— Increase production

Directional Drilling

Specialised types of drilling

Coil tubing drilling

Different types of rigs

Land rig Offshore platform MODU – mobile offshore

drilling unit— Submersible rig— Barge— Tender— Jack up— Semi-submersible (semi)— Drill ship

Land rig

Varying is size depending on the depth of hole that needs to be drilled

— Normally moved on trucks before being re-assembled at a new location

— Some are designed for remote locations and can be transported by helicopter

Offshore platform

Where there are enough reserves to justify the cost a large platform can be installed offshore.

A rig is built on the platform and used for drilling

Submersible rig / Barge

Used close to shore and in very shallow water Rig placed on a barge that is floated in and then

the barge is sunk so that it rests on the bed of the river or sea

Jack up

Similar to a barge Has long legs that are

extended down to seafloor and jack the rig out of the water

Allow it operate in deeper water than a barge

To move, the legs are raised and it’s towed to the next location

Semi-submersible (semi)

Used for drilling in water depths that are too deep for the legs of a jack-up

Floating vessel – held on location by large anchors or in really deep water by using large thrusters controlled by GPS

Drill-ship

Also used in deep water depths

Positioned in same way as SemiSub Can be a converted cargo ship Can carry large loads – good for remote locations

Who owns what at the rig site

Operator – the oil company – has the rights to drill at that location

Drilling contractor – the company who owns and runs the drilling rig

Third party contractors – specialist companies contracted by the operator to supply tools and personnel to carry out specific tasks

— Directional drilling tools— Mud chemicals— Run casing etc

Roles of personnel

Drilling manager - Office— Overall responsibility for the drilling project— Liaison between management and drilling project staff

Drilling superintendent - Office— Responsible for the operation of the project— Liaison between rig and office

Drilling engineer - Office— Responsible for design and planning of the well— Preparing operational plans and budgets

Drilling supervisor (Company Man) – Rig Site— Responsible for the daily operations at the rig site— Ensuring that the operation is carried out in a safe and

efficient manor

Roles of personnel

Completions engineer – Office / Rig Site— Responsible for the design and planning of the completion

Well test engineer - Office / Rig Site— If oil and gas are found the well maybe tested, to determine the

production rates. — The well test engineer plans and runs the well testing operation

Geo-physicist / geologist - Office— Interpret data from seismic surveys and offset wells etc to locate

location of potential reserves

Operations geologist - Office— Works in the office – interprets geological information coming from the

wellsite while drilling is progressing

Wellsite geologist – Rig Site— Works at the wellsite – analyses rock that has been drilled in order to

determine the geology that is being drilled

Roles of personnel

Drilling contractor personnel Tool pusher / Rig Manager

— Senior member of drilling contractor personnel on the rig – manages the daily operation

— Reports to Drilling Supervisor Driller

— Operates the machinery used to drill the hole.— Reports to the Tool pusher

Third party contractor personnel – all third party personnel on the rig report to the drilling supervisor

Mud engineer (can be third party or operator employee) Directional driller Mud loggers

Questions?