2. Part 2_Directional Drilling

7/25/2019 2. Part 2_Directional Drilling

1/18

DIRECTIONAL WELL DRILLI

PART 2

By: Titus N. Ofei

Petroleum Engineering Department

Universiti Teknologi PETRONAS, Malaysia

2015


2/18

DEFLECTION TOOLS FOR KICK


3/18

LEARNING OBJECTIVES (CO1)

At the end of the lecture, students should be able to:

List the main deflection tools for kick-off.

Describe how controlled deflection is achieved for each deflection tool.

State the advantages and limitations of each deflection tool.


4/18

WELL KICK-OFF

In kicking off a well, or making a controlled trajectory chang

deflection tool or method must be used to force the bit in the d

direction.

All deflection methods depend on manipulating the drillpipe

and downward motion) to cause a departure of the bit in eith

direction plane (azimuth), or the inclination plane, or both.


5/18

1. WHIPSTOCK (DOWNHOL

A whipstock is a wedge-shaped casting,

generally of steel with a slightly tapered

concave groove on one side that holds and

guides the whipstock drilling assembly.

A whipstock is used to drill past an

obstruction or deflect the bit out of the main

hole where the casing has been milled.

Open Hole

Whipstock


6/18

KICK-OFF PROCEDURE: WH

1. Run liner hanger packer.

2. Determine the orientation using a gyro

or MWD run.

3. Run retrievable whipstock and mill

window (1 trip system)

4. Drill lateral and retrieve whipstock


7/18

ADVANTAGES/LIMITATIONS OF W

1. Angle and orientation is built-in

for correct kick-off where there

is no angle

2. Start a deviated hole to

sidetrack in conditions unsuitable

for running a downhole drive

(mud motor or turbine)

1. Possible slipping of

whipstock when ge

with the pipe

2. Requires multi trips

retrieve

3. More hardwares in

Advantages Limitations


8/18

2. JETTING

A jetting tool consists of two or three cone

bit with three jet nozzles, two small andone large.

The large nozzle is oriented to the desired

direction where mud is pumped to wash

the formation without drillstring rotation.

They are used to deviate a wellbore in

soft, highly drillable and homogeneous

formations.


9/18

KICK-OFF PROCEDURE: J

1. Orient the large bit nozzle to the

desired formation.

2. Jet to wash a pocket of the formation.

3. Reciprocate the drillstring up and down

to wash out a large jet eye.

4. Continue building the angle with rotary

BHA


10/18

ADVANTAGES/LIMITATIONS OF

1. Simple and cheap

2. Sometimes, its the only way to

build angle in soft formations

3. Orientation is fairly easy

4. Same assembly can be used to

build and rotate

1. Severe doglegs can o

short sections of the h

2. Below 2000-ft TVD, th

normally becomes too

efficient jetting

3. Can only be used at s



11/18

3. PDM WITH BENT SUB - PR

A PDM with bent sub is driven by drilling fluid

pumped down the drillstring to produce rotarypower in the downhole motor.

The drilling fluid is transmitted to the drillbit,

thus eliminating the need to rotate the drillstring.

The bent sub is used to impart a constant

deflection to the tool.


12/18

ADVANTAGES/LIMITATIONS OF PDM WITH

1. They drill smooth curves2. They can be used in most formations

3. Dogleg severity is more predictable

4. Compatible with steering tools and

mud pulse guidance system

1. Motors are expensiv2. Cannot rotate the dr

3. Hole cleaning proble

4. Must be tripped to a



13/18

4. STEERABLE PDM

The most common type of steerable

motor is the single bent-housing design.It permits drilling of a full gauge hole at

the kick-off point, thus eliminating costly

follow-up trips to ream the hole to full

gauge.

Orientation is also more accurate since

the motor penetrates along a smooth

gradual curve in build-up and drop-off

portions.


14/18

Advantages/limitations of steerable PDM

1. They drill smooth curves2. They can be used in most formations

3. Dogleg severity is more predictable

4. Drills faster and compatible with

steering tools and mud pulseguidance system

5. Same configuration can build curves

and rotate the drillstring in tangents

and laterals

1. Motors are expens

2. Temperature limite

3. Chemicals and gas

adverse effects on

stator



15/18

5. ROTARY STEERABLE SYS

This allows for continuous steering while

rotating the drillstring.

Two main types exist:

a) Push-the-bit: applies side force to increase

side cutting action of the bit.b) Point-the-bit: offsets the drilling trajectory

similar to bent sub housing but allowing

continuous rotation.


16/18

ADVANTAGES/LIMITATIONS

1. Steadier deviation control2. Smoother in-gauge hole

3. Better hole cleaning, minimizing

wiper trips

4. Long reach drilling5. Higher overall ROP

6. Continuous acquisition of

azimuthal formation data

1. Expensive



17/18

SUMMARY

Now, you should be able to:

List the main deflection tools for kick-off.

Describe how controlled deflection is achieved for each deflect

State the advantages and limitations of each deflection tool.


18/18

END OF PRESENTATION

Documents

2. Part 2_Directional Drilling