an introduction to drilling (1)

8/7/2019 An Introduction To Drilling (1)

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1 4/13/2011 Confidential Information 2010 M-I SWACO

An Introduction To Drilling

Ron Evett

Specialized Tools UK Sales Manager


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Oil Where it Comes From !

Petroleum, the general name for all carbon

byproducts like oil and natural gas, is formed from

organic material. This material, coming from land or

from dead plankton and other marine organisms,

reaches the floors of bodies of water and becomes

part of the many layers of sedimentary rock that formthere. As these layers form and more layers arrive on

top of them the organic material turns into petroleum

that is contained in the rock, called source rock. This

petroleum becomes oil if the amount of heating and

pressure on the source rock is sufficient but not too

much. To put it simply oil is considered mature

petroleum, whereas source rocks that were heatedless or more than is required to reach the mature

level yield less oil and more natural gas. This occurs

in a time frame of 10 to more than 300 million years


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Types of Wells

Exploration Wells Drilling a well into a prospect to test and appraise the levels of oil and gasthat are present.

Development Wells Drilling a well into a know prospect with the intention to complete and

produce/inject from the reservoir.

Work-Overs Maintenance work carried out existing wells to improve production or correct adeficiency.


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Drilling Solutions Drilling Fluids

Functions of a drilling fluid are:

1. Control Formation Pressure

2. Remove Cuttings

3. Suspend and release cuttings

4. Seal permeable formations

5. Maintain Wellbore Stability6. Minimize reservoir damage

7. Cool and lubricate the drill bit

8. Transmit hydraulic energy to

tools and the bit


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Well Construction Casing and Liners

Marine Riser The section of pipe that

connects the rig floor to the sea bed.

BOP Blow Out Preventers

Casing The section of pipe that is cemented

from the wellhead/seabed down into the well

Liner Sections of pipe that are suspended

from casing by means of a hanger system


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Production Casing

Large-diameter pipe lowered into an

open hole and cemented in place. The

well designer must design casing to

withstand a variety of forces, such as

collapse, burst, and tensile failure, as

well as chemically aggressive brines.

Basic Characteristics

Size 9.5/8

Weight 53.5#

Wall Thickness 0.545

I.D. 8.535 Drift 8.379


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Production Liners

A casing string that does not extend to the top

of the wellbore, but instead is anchored or

suspended from inside the bottom of the

previous casing string. There is no difference

between the casing joints themselves. The

advantage to the well designer of a liner is a

substantial savings in steel, and therefore

capital costs.

Basic Characteristics

Size 7

Weight 29.0#

Wall Thickness 0.408I.D. 6.184

Drift 6.059


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Well Construction - Completions

Completion Types:

Tubing Conveyed Perforation

Open Hole Gravel Pack

Pre-Packed Screens

Multi-Lateral

ESP


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Gravel Pack

A type of sand-control completion in which

the gravel pack screen is packed off in an

open-hole section with no casing or liner to

support the producing formation.


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Submersible Pumps

An artificial-lift system that utilizes a

downhole pumping system that is

electrically driven. The pump typically

comprises several staged centrifugal pump

sections that can be specifically configured

to suit the production and wellborecharacteristics of a given application.

Electrical submersible pump systems are a

common artificial-lift method, providing

flexibility over a range of sizes and output

flow capacities.


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Wellbore Clean-up

Typically between drilling and completion phases the fluid in the well is changed out ordisplaced in order to prepare for running the completion.

During the displacement the host tubulars (casing and liners etc) are cleaned to prevent

the completion being damaged during running or to prevent debris that may have been

left in the well from causing damage to either the formation or the completion itself

during production. Such damage could shorten the life of the well and or bring on the

need for early work-over.

Typically there are two side to any wellbore clean-up:

1. Fluid/Chemical Clean-up

2. Mechanical Clean-up


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Wellbore Clean-up - Fluids

In order to displace the drilling fluid and

prepare the tubulars for the introduction of

brine/completion fluid, a pill train is

typically pumped downhole.

This is designed in order to fully displace

the drilling fluid and then typically turn thetubulars from an oil wet to a water wet

condition


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Wellbore Clean-up Mechanical

Mechanical Wellbore Clean-up Systems have been designed to effectively clean all typesof casings and liners and assist with debris extraction from the wellbore duringdisplacement to completion fluids.

Theses tools can be categorised as: -

Liner Top Test Tools

Casing Cleaning ToolsCirculating Tools

Debris Recovery Tools

Riser Cleaning Tools

BOP Cleaning Tools

Wellhead Cleaning Tools

Ancillary Tools

Customized Tools


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Wellbore Productivity Completion Fluids

A solids-free liquid used to "complete" an oil or gas well. This fluid is placed in the well to facilitate finaloperations prior to initiation of production, such as setting screens production liners, packers, downhole valves

or shooting perforations into the producing zone. The fluid is meant to control a well should downhole hardware

fail, without damaging the producing formation or completion components.

Functions of a completion fluid are:

1. Maintain Hydrostatic in the well2. Provide a clean environment for the completion

3. Be non-formation damaging

Inhibitors added:

1. Corrosion Inhibitor

2. Oxygen Scavenger3. Biocide


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Wellbore Productivity Filtration

Basic Filtration Systems:

1. Bag Filter

2. Cartridge Unit

3. Filter Press and Cartridge Unit


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Wellbore Productivity Filtration

Filtration is required to provide the

cleanest possible environment for

the completion to exist in and to

protect the formation from invasion

of unwanted particulate.

The removal of debris from

completion fluids is required toprotect the completion components

and avoid the necessity for the well

to be worked over prematurely.


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Wellbore Productivity Pit Cleaning

Fluid is held within the rigs pit system before being pumped downhole.Therefore if the pits are not cleaned thoroughly before brine is transferred then

contamination will occur and well clean-up will be extremely time consuming.

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an introduction to drilling (1)

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