Directional Drilling B 01 Jan 2011 Report

7/30/2019 Directional Drilling B 01 Jan 2011 Report

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DIRECTIONAL DRILLING

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DIRECTIONAL DRILLING

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Directional drilling is defined as an art and

science involving deflection of a well bore in a

specified direction in order to reach a

predetermined object below the surface of the

earth.

NON PETROLEUM APPLICATIONS

Mining industry. Construction industry.

Geo thermal engineering.

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APPLICATIONS OF DIRECTIONAL DRILLING

1. Multiple wells from single location.2. Inaccessible locations.

3. Drilling to avoid geological problems.

Fault drilling.

Salt dome drilling.

4. Side tracking and straightening.

5. Relief well drilling.

6. Controlling straight holes.7. Horizontal well.

8. ERD well.

9. Multilateral drilling.

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MULTIPLE WELLS FROM SINGLE LOCATION

Optimum number of wells can be drilled from a single

platform or artificial island. This greatly simplifies

gathering systems and production techniques .

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INACCESSIBLE

LOCATIONS

If reservoir located

under river beds,

mountains, cities etc,this technique of

directional drilling is

used .

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DRILLING TO AVOID GEOLOGICAL PROBLEMS

A. FAULT DRILLING:

This eliminates the hazard of drilling a vertical well

through steeply inclined fault plane which could slipand shear the casing.

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B. SALT DOME

DRILLING

To reach the producing

formation which often lieunderneath the over

hanging cap of the dome,

the well is first drilled at

one side of the dome andis then deviated to

producing zone to avoid

drilling problems such as

large washouts, lost

circulation and corrosion .

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SIDE TRACKING & STRAIGHTENING

It is used as remedial operation either to side track

obstruction by deviating well bore away from obstruction

by deviating the well bore back to vertical by

straightening out crooked holes.

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RELIEF WELL DRILLING

The technique is applied to the drilling of relief wells so

that mud may be pumped into the reservoir of the

uncontrolled well.

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ERD WELL

Advantages:1.Increased horizontal displacement from

central platform.

2. Increased penetration length of reservoir.3. Require less number of wells to develop a

field.

4. Require less number of platforms to

develop a field in offshore.

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ERD WELL

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HORIZONTAL WELLAdvantages:

1.Increasing the drainage area.2.Prevention of gas coning or water coning

problems.

3.Increased penetration of the producingformation.

4.Increasing the efficiency of enhanced oil

recovery ( EOR ).5.Improving productivity in fractured

reservoirs by intersecting a numbers of

vertical fractures.15


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HORIZONTAL WELL

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MUTILATERAL DRILLING

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Mutilateral. Drilling

Multilateral well has been defined as a wellthat has more than one horizontal or near

horizontal laterals drilled from single site and

connected back to a single well bore.Applications

. Greater reservoir exposure.

Drain more than one reservoir.

Exploit irregular reservoirs efficiently.

Speed up reservoir drainage.

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Mutilateral. Drilling

Reduction in drilling cost per unit length

of the well bore contacting, the reservoir

rock.

Ability to obtain a given length ofhorizontal well bore in reservoir where

drag would perhaps limit the length of

single horizontal well bore. Reduction in number of slots and thus

the number of production platforms.

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Reentering existing wells

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A. MINING INDUSTRY

- Directional wells are used to producemethane gas that is contained in coal seams.

- Methane presents a safety hazard and must

be drained off before mining operations canbegin.

-In deep coal seams that are beyond the reach

of conventional mining techniques, directional

wells can be drilled for in situ gasification

projects.

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A. MINING INDUSTRY

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B. CONSTRUCTION INDUSTRY

A small diameter pilot hole is drilled in a

smooth arc beneath the river until it

immerges on the other side. This acts as a

guide for the large diameter pipe forming

the conduit.

The hole is drilled through soft sediments

about 40 below the river bed. This

techniques has been used to cross rivers

up to 200 wide.

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B. CONSTRUCTION INDUSTRY

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C.GEO THERMAL ENGINEERING

High geothermal gradient found in some

rocks( e.g. granite) can be harnessed toprovide energy.

Extracting the heat from this rocks requires

the drilling of injection and productionwells.

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C.GEO THERMAL ENGINEERING

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AZIMUTH

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AZIMUTH

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QUADRANTS

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QUADRANTS

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A radius of 100ft is commonly

used as target zone depending

on particular requirements e.g

a relief well requires much

smaller target in order to be

effective. Smaller the target,

greater number of correction

runs. So longer drilling time ,

high drilling costs. So the

target zone should be as large

as the geologist/reservoirengineer can allow. DDs job is

then to place the wellbore

within the target zone at

minimum cost

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TYPES OF WELL PROFILESa. L- TYPE

b. S- TYPE

c. J- TYPE

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TYPE I (BUILD AND HOLD OR L TYPE)

This is the most common and simplest

profile for a directional well. The well is drilled down vertically to KOP,

where the well is deviated to required

inclination and further maintained to target.

Shallow KOP selected to reduce inclination.

This profile can be applied where large

displacements are required at relatively

shallow target depths. Under normal condition inclination should be

15 to 55.

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TYPE II (BUILD HOLD AND DROP OR S

TYPE)

This profile is similar to type-I up to tangentialsection. Here the profile enters a drop of section

where inclination is reduced and in some cases

becomes vertical as it reaches the target.

More torque and drag can be expected due to theadditional bend.

Used where target is deep but horizontal

displacement is relatively small.

It has also application when completing a well thatintersect multiple producing zones.

Drilling of relief well where it is necessary to run

parallel to wild well

Lease or target limitations. 40


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TYPE III (DEEP KICK OFF AND BUILD J

TYPE) Initial deflection is started well below the surfaceand angle is built up to bottom.

It is used in particular situations like salt dome

drilling, fault drilling and side- tracking or

repositioning of target.

Disadvantages:

Formation may be harder & less responsive

to deflection. More tripping time to change BHA while

deflecting.

BUR is more difficult to control.42


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HORIZONTAL WELL PROFILES

HORIZONTAL WELLS ARE CATEGORIZEDBY THE RADIUS OF CURVATURE ADOPTED

TO MAKE THE WELL HORIZONTAL. THEY

ARE ALSO CLASSIFIED BY BUILD UP RATES

WHICH IS INVERSELY PROPORTIONAL TOTHE RADIUS OF CURVATURE:

LONG RADIUS

MEDIUM RADIUS SHORT RADIUS

ULTRA SHORT RADIUS

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HORIZONTAL WELL TYPES

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BUILDUP SECTION BETWEEN 1- 6/100 OR RADIUS LENGTH BETWEEN1000-5000

ADVANTAGES:-

EASIER AS CONVENTIONAL DOWNHOLE HARDWARE IS USED

PDM MAY NOT BE REQUIRED

LOWER DOG - LEG SEVERITY GIVES LESS TORQUE AND DRAG

LONGER LATERAL SECTIONS(3500 TO 5000) (1000M TO 1500M)

EXTENDED REACH FROM SURFACE LOCATIONS

ACCOMMODATES FULL LOGGING ALL COMPLETION METHODS

STIMULATION WORKOVER AND GASLIFT EQUIPMENT.

DISADVANTAGES:-

LONG RADIUS NECESSITATES BIGGER RIG, TOP DRIVE, LARGERPUMPS AND GREATER MUD MANAGEMENT CAPABILITIES

LONGER OPEN HOLE SECTIONS INCREASE RISK OF PIPE STICKING

,KICKS AND BOREHOLE DAMAGE

LESS PRECISE CONTROL OVER T.V.D

LITTLE USE IN SMALL LEASES BECAUSE OF LONG

DISPLACEMENTS.

Long Radius

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BUILDUP SECTION BETWEEN 8-20/100 OR RADIUS LENGTH

BETWEEN 716 TO 286(218M TO 87M)

ADVANTAGES:-

SUPERIOR IN PRECISION COMPARED TO LONG RADIUS

ACCOMMODATION OF NORMAL/SMALL SIZE M.W.D TOOLS

ABLE TO DRILL LONG HORIZONTAL SECTION UPTO 5000

DISADVANTAGES:- TORQUE AND DRAG HIGHER THAN LONG RADIUS

LIMITATION IN COMPLETION AND WORKOVER

OPERATIONS

Medium Radius

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Short Radius


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Buildup section between 1-3.5/1 and radius

length between 57 to 16

Advantages:-

Precise vertical placement of horizontal drain

KOP below fluid contacts results less risk of

poor isolation

Disadvantages:-

Requires customized drilling equipment

No control over bore hole azimuth (within 20) Limited to open hole completion

No coring and logging services52


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Directional Drilling B 01 Jan 2011 Report