MWDMWDMWDMWDMWDMWDMWDMWDIntroductionIntroductionIntroductionIntroductionIntroductionIntroductionIntroductionIntroduction

Andrea NavajasAndrea NavajasMWDMWDDrilling & MeasurementsDrilling & Measurements

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Directional Drilling (DD)Directional Drilling (DD)Directional Drilling (DD)Directional Drilling (DD)Tools to optimize directional control from kickoff to target

PowerPak MotorsPowerDrive Rotary Steerable System

Measurements While Drilling (MWD)Measurements While Drilling (MWD)Measurements While Drilling (MWD)Measurements While Drilling (MWD)Mud Pulse Telemetry and Surveying ToolsPowerPulse, IMPulse, SlimPulse, E-Pulse, Gyro-Pulse

Logging While Drilling (LWD)Logging While Drilling (LWD)Logging While Drilling (LWD)Logging While Drilling (LWD)Provides formation evaluation measurements

Resistivity (arcVISION, geoVISION)Density Neutron (adnVISION)

D&M ServicesD&M ServicesD&M ServicesD&M ServicesD&M ServicesD&M ServicesD&M ServicesD&M Services

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1. Introduction1. Introduction

The MWD tools in use today are able to provide

data for a variety of measurements such as

real-time formation measurement (shown here)

data for correlation and pore pressure analysis,

including resistivity, density and porosity

measurements of the formation,

real-time surveys, including inclination, azimuth,

and toolface, allowing the driller to steer the

well for directional control, and

real-time drilling mechanics data for drilling

efficiency, including downhole weight-on-bit

and downhole torque-at-bit.

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While drilling is taking place, the drilling fluid, or "mud", is pumped

through drillpipe connecting the surface equipment to the bottomhole

assembly (BHA).

Data from some of the MWD tools is transmitted uphole to the surface

by mud pulse telemetry, while other tools transmit data to the surface

electronically via a wire and are referred to as wireline MWD systems.

The pulses are converted to electrical

voltages at the surface by a transducer

mounted in the mud pump discharge piping.

The surface equipment then decodes the

information, which represents

measurements by the tool.

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Both MWD and LWD data are

transmitted in real time to the

surface. However, LWD provides

better resolution than MWD

because the LWD measurements

are commonly stored in

downhole memory. The MWD

measurements have data

transmission limitations, which

hinder the resolution of the

measurement values.

Logging while drilling (LWD)Logging while drilling (LWD)Logging while drilling (LWD)Logging while drilling (LWD) is closely related to MWD. LWD provides

formation measurements, while MWD provides drilling mechanics and survey

measurements.

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2. MWD System components2. MWD System components2. MWD System components2. MWD System components2. MWD System components2. MWD System components2. MWD System components2. MWD System components

Anadrill manufactures a range of

MWD tools and systems to meet

the requirements of its customers.

All of the MWD tools are made up

of the same major surface and

downhole components even

though each type of tool is

designed to meet a specific need.

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The MWD surface system

components consist of:

surface sensors for measuring

surface drilling parameters, as

well as the wells depth,

a transducer at the surface to

receive the measurement signals

from the MWD tool,

a computer for decoding downhole

data at the surface, and

a computer for processing, storing,

and using all of the data.

2.1 MWD Surface System Components2.1 MWD Surface System Components2.1 MWD Surface System Components2.1 MWD Surface System Components

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2.2 MWD 2.2 MWD 2.2 MWD 2.2 MWD DownholeDownholeDownholeDownhole System ComponentsSystem ComponentsSystem ComponentsSystem Components

The MWD downhole tool

components consist of:

a component to supply the

power needed to make

downhole measurements,

one or more components for

making downhole

measurements, and

a component for producing and

transmitting the measurement

signals to the surface.

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3. MWD System Component Functions3. MWD System Component Functions3. MWD System Component Functions3. MWD System Component Functions3. MWD System Component Functions3. MWD System Component Functions3. MWD System Component Functions3. MWD System Component Functions

3.1 Power Supply3.1 Power Supply3.1 Power Supply3.1 Power Supply

Batteries, or downhole

alternators, supply power to the

tools. The batteries allow the

tools to operate without the flow

of mud, but the operating time

and sensor power output is

limited. The alternators need

mud flow to generate their power

and can work in a wide range of

flow rates

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3.2 Measurement3.2 Measurement3.2 Measurement3.2 Measurement

All MWD systems measure the

direction and inclination (D&I) of the

wellbore. The measurements are used

to accurately map the well so the driller

can guide the bit to its ultimate or

intermediate targets, as well as avoid

other wells. The well being drilled may

require specific turn and build rates.

The MWD tool may also have the ability

to make secondary measurements,

such as downhole weight on bit and

annular temperature.

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3.3 Signal Production3.3 Signal Production3.3 Signal Production3.3 Signal Production

The tools measuring device

produces data signals that need

to be sent to the surface.

Because the MWD tool is remote

from the driller, it is necessary to

transmit the data by way of a

signal from the tool to the driller.

This must be done in a manner

that maximizes data transmission

and reliability and minimizes the

impact on drilling operations.

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3.4 Transmitting and Telemetry3.4 Transmitting and Telemetry3.4 Transmitting and Telemetry3.4 Transmitting and Telemetry

MWD systems use mud pulse

telemetry to transmit survey data

to the surface. Analog signals

produced by the tool measuring

devices are converted into digital

signals (1 and 0). The digital

signals are then converted into

pressure pulses that carry the

data to the surface through the

column of drilling fluid.

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3.4.1 Mud Pulse Telemetry 3.4.1 Mud Pulse Telemetry 3.4.1 Mud Pulse Telemetry 3.4.1 Mud Pulse Telemetry DownholeDownholeDownholeDownhole

Information is transmitted to the surface through the mud by way of

a data signal created downhole. The surface equipment decodes the

data signals of the measurements so that the driller can make

adjustments. The three common types of signals generated are

positive pulse telemetry, negative pulse telemetry and continuous

wave telemetry.

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Positive Pulse TelemetryPositive Pulse TelemetryPositive Pulse TelemetryPositive Pulse Telemetry

A flow restrictor produces positive pulses as illustrated in the graphic.

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Negative Pulse TelemetryNegative Pulse TelemetryNegative Pulse TelemetryNegative Pulse Telemetry

A diverter valve produces negative pulses as illustrated in the graphic.

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Continuous Wave TelemetryContinuous Wave TelemetryContinuous Wave TelemetryContinuous Wave Telemetry

Rotating plates produce continuous waves as illustrated in the graphic.

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3.4.2 3.4.2 3.4.2 3.4.2 WirelineWirelineWirelineWireline TelemetryTelemetryTelemetryTelemetry

Data can also be sent to the surface

through a wire attached to the MWD tool.

This method was common with older types

of tools (called steering tools). However,

with an attached wire, the drillstring

cannot be rotated. Today, wireline is used

in conjunction with coiled tubing, where

the drillstring is a continuous length of

metal pipe fed into the wellbore from a

drum and so cannot be rotated.

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3.5 Receiving and Decoding3.5 Receiving and Decoding3.5 Receiving and Decoding3.5 Receiving and Decoding

A transducer (or sensor) at the

surface receives the pressure

pulses and converts them to

electrical signals. A surface

sensor is not necessary for the

wireline type of MWD.

Surface computers decode the

electrical signals from the

transducer and turn the digital

information into engineering

values and survey computations.

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An important function of the surface computer

is to process the data of the local conditions,

such as hole size and depth. The data

produced by the MWD tool is processed and

used to provide information about the well.

This information is used to make critical

decisions about the drilling process, such as

the well direction.

3.6 Data Processing and Usage3.6 Data Processing and Usage3.6 Data Processing and Usage3.6 Data Processing and Usage

An important function of the surface computer is to process the data of the local

conditions, such as hole size and depth. The data produced by the MWD tool is

processed and used to provide information about the well. This information is used to

make critical decisions about the drilling process, such as the well direction.

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3.7 Display3.7 Display3.7 Display3.7 Display

Monitors display data in

realtime on the drillfloor so that

the driller can make well

steering decisions. Displays

are used in the Anadrill unit to

allow for production of logs (a

plot of data against depth) and

making formation-evaluation

interpretations. With remote

data links, displays located at

the clients office allow them to

view MWD data from the

wellsite.

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3.8 Control 3.8 Control 3.8 Control 3.8 Control DownholeDownholeDownholeDownhole

MWD allows the driller to control

downhole drilling in real time.

Directional information is sent to

the surface continuously so that

course corrections can be made.

MWD tools make applications

like geosteering possible. The

driller can use the measurement

data to maximize the productive

length of a wellbore within a

reservoir.

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4. How MWD Components Work4. How MWD Components Work4. How MWD Components Work4. How MWD Components Work4. How MWD Components Work4. How MWD Components Work4. How MWD Components Work4. How MWD Components Work

4.1 Power Supply4.1 Power Supply4.1 Power Supply4.1 Power Supply

Power is supplied to the tools by

batteries or alternators. The

batteries give power without the

need for mud flow. An alternator

uses mud flow to turn a turbine.

The turbine generates enough

current to power the MWD tools

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4.2 Signal Production, Transmitting, and Telemetry4.2 Signal Production, Transmitting, and Telemetry4.2 Signal Production, Transmitting, and Telemetry4.2 Signal Production, Transmitting, and Telemetry

Positive Pulse TelemetryPositive Pulse TelemetryPositive Pulse TelemetryPositive Pulse Telemetry

Positive pulse telemetry uses a flow restrictor (or plunger mechanism) that

closes to increase standpipe pressure when activated. As the mud flows

through the pipe, the pressure fluctuates as the plunger mechanism opens and

closes. The highs and lows of pressure, as sensed by a transducer on the

standpipe, are transmitted to the surface as ones or zeros and are decoded as

data.

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Negative Pulse TelemetryNegative Pulse TelemetryNegative Pulse TelemetryNegative Pulse Telemetry

Negative pulse telemetry uses a diverter (or flapper) valve. When the flapper

valve is open the drilling fluid is diverted to the annulus, creating negative

pulses as the pressure fluctuates. The pressure changes are identified and

decoded at the surface as data.

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Standing or Continuous Wave Standing or Continuous Wave Standing or Continuous Wave Standing or Continuous Wave PulsersPulsersPulsersPulsers

Standing or continuous wave pulsers, also known as mud sirens, are a type of

positive pulse telemetry. Rotating baffled plates are used to temporarily

interrupt mud flow, creating a pressure wave in the standpipe. A carrier wave

is formed, allowing information to be embedded within the carrier wave by

changing the waves phase or frequency. The information carried by the wave

is identified at the surface and decoded.

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4.3 Receiving and Decoding4.3 Receiving and Decoding4.3 Receiving and Decoding4.3 Receiving and Decoding

Pressure pulses are received and converted to electric voltages by a

transducer installed in the mud pump discharge piping. The surface

computers then perform the pressure pulse decoding and survey

computations to convert the data into useful measurements.

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4.4 Data Processing4.4 Data Processing4.4 Data Processing4.4 Data Processing

Anadrills Integrated Drilling Evaluation

and Logging (IDEAL*) system combines

downhole directional drilling, drilling

mechanics, and petrophysical data

measurements within a few feet of the bit

and transmits the data to the surface in

real time. Downhole data is merged with

relevant surface measurements and is

automatically checked and translated

into useful information. The information

can be displayed simultaneously on the

rig floor, in the surface unit, and in the

company representatives office.

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5. D&M MWD tools5. D&M MWD tools5. D&M MWD tools5. D&M MWD tools5. D&M MWD tools5. D&M MWD tools5. D&M MWD tools5. D&M MWD tools

IMPulse

SlimPulse

PowerPulse

TeleScope

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5.1 SlimPulse5.1 SlimPulse5.1 SlimPulse5.1 SlimPulse

It is the latest retrievable and re-seatable slim tool

It provides inclination, azimuth, MFT, GTF, GR (optional), transverse

shocks and tool temperature

It is combinable with various ARC tools, CDR and ISR

It supports flow rates from 35 to 1200 gpm

It is powered by lithium batteries, with supplementary power

supplied from the pulser when the mud is flowing

Tool sizes are: 1 7/8, 2 1/8, 2 3/8, 2 5/8 and 4 5/16

It has an LCM tolerance of 50 ppb (medium nut plug)

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5.2 5.2 5.2 5.2 PowerPulsePowerPulsePowerPulsePowerPulse

PowerPulse is the most common MWD tool system in the field.

It is designed for hole sizes down to 8 1/2 (6 3/4 tool)

The PowerPulse can measure inclination, azimuth, GTF, MTF, transverse shocks and tool temperature. Formation gamma ray, DWOB, DTOR, and APWD are optional

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PowerPulse is the most common MWD tool system in the field.

It is designed for hole sizes down to 8 1/2 (6 3/4 tool)

The PowerPulse can measure inclination, azimuth, GTF, MTF, transverse shocks and tool temperature. Formation gamma ray, DWOB, DTOR, MVC and APWD are optional

5.2 5.2 5.2 5.2 PowerPulsePowerPulsePowerPulsePowerPulse

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6. Survey Definition6. Survey Definition

A survey is simply three

measurements made at a point

below the surface of the earth:

Measured Depth

Inclination

Azimuth

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A point along the path of a well is defined by a directional survey. The survey consists of:

A Measured Depthalong the well path

An Inclinationat that measured depth

An Azimuthat that measured depth...

We use the survey to calculate the position of the point in space using one of the four survey calculation methods described at the end of this presentation.

Downhole surveys are taken by the MWD tool using accelerometers and magnetometers that measure the gravitational force and magnetic field strength at a survey point. These measurements are used tocalculate the inclination and direction of the survey point.

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InclinationInclination

Inclination is the angle between a vertical line and the path of the well bore at that point.

To determine the inclination of a survey point the MWD tool measures its orientation to the gravitational vector.

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Azimuth is the angle between Azimuth is the angle between North Reference and a horizontal North Reference and a horizontal projection of the current Survey projection of the current Survey positionposition

To determine the azimuth of a survey To determine the azimuth of a survey

point, the point, the MWD toolMWD toolmust measure the must measure the

Magnetic field (this allows us to get Magnetic field (this allows us to get

the North reference).the North reference).

AzimuthAzimuth

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Measuring D&I with MWD toolsMeasuring D&I with MWD tools

The MWD tool measures the Inclination of the well bore by measuring the direction of the earths Gravitational Field relative to the tool.

The MWD tool measures the Azimuth of the wellbore by measuring the direction of the earths Magnetic Field relative to the tool.

The depth measurement comes from our surface sensors

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7. Signal Demodulation7. Signal Demodulation

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HSPM Demodulation WindowHSPM Demodulation Window

Survey FrameUtility Frame

Repeating Frames

PressureRecorder

Default Frame ID DSPScope Receiver

Signal Strength Indicator and Signal Loss Threshold

ReceiverInput

BitConfidence

FrameDecoderStatus

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DSPScopeDSPScopeDisplays (1/2)Displays (1/2)

Time

Freq

u enc

y

Select Spectrogram

PowerSpectrum

Signal Strength(red)

Bit Confidence(blue)

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Low Low Low Low Low Low Low Low SignalSignalSignalSignalSignalSignalSignalSignalStrengthStrengthStrengthStrengthStrengthStrengthStrengthStrength

Causes of Low Signal StrengthCauses of Low Signal StrengthCauses of Low Signal StrengthCauses of Low Signal Strength

Drilling conditions can cause low signal strength at the surface. The

following are the most common causes of low signal strength.

Depth of the well

High mud viscosity

Mud flow rate

Mud condition

Signal frequency

Pipe ID

Radiation loss

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Depth of the WellDepth of the WellDepth of the WellDepth of the Well

The MWD signal always loses some energy as it propagates uphole to the surface. As

the MWD tool goes deeper, the signal must travel over longer distances. The longer the

distance, the more signal energy that is lost.

High Mud ViscosityHigh Mud ViscosityHigh Mud ViscosityHigh Mud Viscosity

High mud viscosity produces more friction between the mud molecules. Friction weakens

the signal as it propagates uphole through the mud. Viscosity is the biggest destroyer of

the MWD signal. In colder climates, the mud cools and gels in the mud pits. This

increases mud viscosity.

Mud Flow RateMud Flow RateMud Flow RateMud Flow Rate

The mud flow rate is the major consideration when setting the MWD tool modulator gap.

When the gap is too large for the flow rate, the tool produces a weak signal.

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Mud ConditionMud ConditionMud ConditionMud Condition

Gas or air in the mud has the effect of weakening the signal. For example, malfunctioning

pumps can pump air into the mud, thereby reducing signal strength as the signal

propagates uphole.

Signal FrequencySignal FrequencySignal FrequencySignal Frequency

Low frequency waves propagate through the mud better than higher frequency waves

because the mud acts as a lowpass filter. Low frequency energy passes through the mud

while the energy at higher frequencies is filtered out. This filtering effect is more

pronounced with increasing depth. The severity of the filtering effect varies depending

on mud type.

Pipe IDPipe IDPipe IDPipe ID

The drillstring can be made up from several different sizes of drillpipe. The smaller the

internal diameter of the pipe, the greater the loss of signal energy (attenuation) due to

friction as the signal propagates uphole inside the drillstring.

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Drilling NoiseDrilling Noise Drilling noise occurs at verylow frequencies.

Some formation types and drill bits cause more drilling noise than others.

With SlimPulse and IMPulselow frequency modes, choosethe highest carrier frequency within the pump stroke rate limitations.

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Mud Motor StallsMud Motor Stalls Mud motor stalls are very bad for both the motor itself and for telemetry.

Repeated motor stalls make drilling very inefficient.Driller has to keep recovering from the stalls.

Ensure mud motor ismatched to drilling conditions.

Reduce WOB

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Identifying Downhole NoiseIdentifying Downhole Noise

Drilling NoiseRotating Sliding

Rotary Noise

Pump Noise

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Electrical Noise (1/2)Electrical Noise (1/2)

Electrical noise is broadband noise.