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Petroleum Engineering Seminars

Rui Francisco 36344

Directional Drilling

Index


Introduction

History

Aplications

Profile

Equipment

Conclusion

Introduction


Directional drilling is the art and science involving the intentional deflection of a

wellbore in a specific direction in order to reach a predetermined objective below

the surface of the earth.

(The practice for drilling non-vertical wells)

Rate of Build / Drop _ DLS – Dog leg severity is a measure of the amount of

change in the inclination, and/or azimuth of a borehole, usually expressed in

degrees per 100 feet (30 meters) of course length.

DLS > 4º a 6º / 30 meters Drag and Torque; Keyseat

Well Path Data Record Deviat. Survey Geological Data

History


Industry Driven vs Technology Driven (How – Where – Why)

Many prerequisites enabled this suite of technologies to become productive.

Probably, the first requirement was the realization that oil wells are not

necessarily vertical – 1920s.

The first controlled directionally drilled well was drilled in

the Huntington Beach Field in 1930 to tap offshore

reserves from land locations.

The first multilateral well was drilled in the Soviet Union

in 1953

Directional drilling became more widely accepted after a

relief well was drilled near Conroe, Texas in 1934.

In the erlys 1940s the wells were drilled with horizontal

displacements from 30 m to 150 m.

History


The 1990s upsurge in exploration activity saw a sustainable interest in

directional drilling, and the technique emerged as the prefered option for

production wells in several countries.

During the 1980s, directional drilling was difficult and comparatively costly. As a

result, it failed to achieve broad acceptance wthin the industry.

Oil and Gas companies spend around USD 20 billion on drilling each year, from

which 15% are attributed to losses

Measurement While Drilling – 1978

Steerable Motors – 1986

Acceptable Surveys – 1992

Rotary Steerable Systems – 1997

Today, directional wells have been drilled in every oil and gas basin, and the

technology is so efficient that has become a standard industry tool.

Applications


Side track well, to go

around a stuck BHA

Multiple sidetrack for

well logging or

reservoir better

positioning

Multiple wells from a

single structure

Applications


Inaccessible surface

location

Drilling around salt

domes

Steeply dipping sands

can be drilled with a

single wellbore

Applications


Fault drilling at higher

incident angle

Relief well drilling

HDD. Increasing

exposure of the

reservoir to increase

productivity

Applications


Optmize Reservoir Exploitation

Vertical Wells Directional Wells

57 2

2.000 m3/d – 19 years 5.000 m3/d – 7,6 years

Disavantages

Drag and Torque

Rate of perfuration

Adjustment and repair works

Sand influx

Costs

Profile


Trigonometry

Software

Equipment


Rate of Penetration

Direction

Efficiency

Safety

Measurement

While Drilling

Accurate

Deviation

Surveys

Rotary Steerable

Systems

Telemetry

Systems

Electronic

Compass

Ob

jective

E

qu

ipm

en

ts

Data

Transmission

Measurement

Instruments

Drilling / Steering

Tools

Te

ch

no

log

y

Equipment


Whipstock: A long wedge dropped or placed in a petroleum well in

order to deflect the drill

Equipment


Rotary Bottom Hole Assembly: Consists of a bit, drill collars,

stabilizers, reamers that affects the trajectory of the bit and,

consequently, of the wellbore.

Equipment


Limitations in slide mode:

Difficulty to slide and to maintain orientation;

Poor hole cleaning; Lower penetration rate;

Higher wellbore tortuosity; Differential pressure

sticking

Steerable Positive Displacement Motor: Converts the hydraulic power

of the fluid into mechanical power to cause the bit to rotate. Uses bent

subs or bent housing.

Equipment


Rotary Steerable System: A tool designed to drill directionally with

continuos rotation from the surface, eliminating the need to slide a

steerable motor.

Equipment


Gyroscopic Sensors: Is composed of a spinning wheel mounted on a

shaft and powered by an electric. The spinning wheel direction is

maintained by its own inertia; therefore, it can be used as a reference for

measuring azimuth

Gravity Accelerometers: Measure the Earth’s gravitational field in the

x, y, and z planes

Pendulum: This method relied on the period of a pendulum's oscillation

adjusted by variations in gravity due to changes in altitude and latitude

INCLINATION AND AZIMUTH

Magnetic Sensors: Measure components of the Earth’s magnetic field.

Must take into account the variations in the Earth magnetic field and any

external interference

Equipment


Wired Drill Pipe Telemetry: These systems use electrical wires built

into every component of the drillstring, which carry electrical signals

directly to the surface

Electromagnetic Telemetry: To transmit data, the tool generates an

altered voltage, wich is transmited to the surface and decoded by a

computer

Mud Pulse Telemetry: A valve is operated creating pressure

fluctuations representing the information. The pressure fluctuations

propagate whithin the driiling fluid and is processed to reconstruct the

information

Telemetry Systems Conversion and transmission to surface of a logging tool measurement

Conclusion


No Drilling Surprises: Real time

comunications with the headquarters and

computer processing, creating a real time

cycle, which promotes continues review

and refinement of drilling operations

Uncertainty: Rather than specifyng a

point in space, surveying engineers

consider wellbore position to be within an

elipsoid of uncertainty (EOU)

Conclusion


Acronyms Glossary:

TVD True Vertical Depth

ROP Rate of Penetration

BHA Bottom Hole Assembly

WOB Weigth on Bit

LWD Logging While Drilling

MWD Measurement While Drilling

RSS Rotary Steerable System

DLS Dog Leg Severity

RKB Rig Kelly Bushing

Thank You

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