04 hal-2011 telemetry and depth tracking f

8/19/2019 04 HAL-2011 Telemetry and Depth Tracking F

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Telemetry and Depth Tracking

Sperry Dril ling Services

13th Dec 2011

“For External Distribution. © 2005 Halliburton. All Rights Reserved.”

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Telemetry

• Transmission of data from M/LWD tool downhole to

surface

• RealTime data for decision making while the drilling

progress

• Mud Pulse telemetry• Electromagnetic telemetry


• re p pe e eme ry


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Mud Pulse Telemetry• Acquiscit ion o f M/LWD data

• M/LWD tool decode the data

into pulse time intervals

• Pressure ‘pulses’ made

downhole

• Transmitted inside the

drillstring, through the mud

column• Pressure ‘pulses’ detected by


M/LWD

• Time interval between pulses

decoded back into data bysurface computer

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Positive Pulse

• Restrict the flowpath

inside the drillstring

• Causing sudden

increase of pressure

‘pulses’

• Pressure variation

detected at surface

• Decoded by surfacecomputer



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Negative Pulse• Venting mud from

inside the drillstring

to the annulus

• aus ng su en rop

of p ressure

• Pressure variation

detected at surface

• Decoded by surfacecomputer


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Mud Pulse Telemetry

• Relies on good pulse

detection at surface

• Factors affecting detection

– ump no se

– Drilling noise

– Mud condition

– Depth

• Signal attenuation, 80 psi pu lse

generated at 4,500m will be

10psi at surface


Detection at 3316 m, Rig A


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Mud Pulse Telemetry

• Pressure transducer installed

on surface

– Standpipe

– umps

– Gooseneck

• Detects very small pressure

‘pulses’ which may not be

visible on o ther pressureindicators


acquire the best out ofmanufacturing

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Mud Pulse TelemetryDetection at 3650m, Rig B

Transmitted data pulse from downhole is not

decodable at surface


Detection at 3316 m, Rig A


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Pulsation dampener

• Reciprocating mud pumps

induce pressure pulsation at a

certain frequency

• The pulsation is affected by

the pump speed

• Pulsation dampener reduce

the vibration and noise

• Standard part of rig pump on


mos r g

• Requires proper maintenance

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Other factors affecting detection

• Drilling noise is a natural part of

drilling

• Excessive vibration will i nduce largeDrilling noise

• Viscosity of the mud

• Mud which have remained static for

a while• High LCM contents causing signal

Mud Condition

• Excessive pump no ise


Others• Washout of drillst ring

• Debris accumulating on the pulser

• Any leakage in the f low loop


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Other types of Telemetry system


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Electromagnetic telemetry

• First commercial system launched

in 1995, 800+ well s betw een 2003 -

2005

Drillpipe acts ascenter Conductor

• oes no requ r e a so co umn

of fluid for data transmission

• Battery powered, does not require

pumps on for operation

• Full two-way communication


Earth’s Formations act

as lossy outer conductor


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Electromagnetic telemetry

• Indonesia EM experience

• Benefits

- Independent of mudflow

- No moving parts- e co uma ra over year s

- Chevron Sumatra

• App licat ions

• Currently limited to onshore

•

- Higher data rates

- less limited by LCM


• Advantage for underbalanced

operation

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Wired pipe telemetry


• Intellipipe, incorporating specialized drillipipe w ith integrated

conductor for data transmission

• Recorded data quality i n RealTime


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Questions?


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How to communicate with

M/LWD downhole?



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M/LWD Communication

• M/LWD tools are traditionally one-way communicationequipment


• own o e en es pumps on o con on roug

rotation of the impeller. No Rotation = Pumps off

• Pump cycling to

– Take survey

– Reset the M/LWD Tool downhole

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• Geospan installed at standpipe with venting valve

• Creating pressure drop at the standpipe to send

command to the tool downhole

Downlink Command

Sending a pulse downhole instead of uphole



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Geospan• Briefly venting off flow

from the flowline by

opening/closing the

va ve

• Pressure drop at surface

• Sequence of pulses to

send specific commands


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• PWD detects the pulses

downho le from the internal

pressure sensor

• Pulses decoded into

Donwlink Commands

commands

• Various commands

– GeoPilot commands

– Survey

– Reset M/LWD Tool – GeoTap commands


– others

PWD


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Questions?


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Depth Tracking



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Depth tracking

Depth

• Primary depth reference• Measured by the length of

Driller’s Depth Logger’s Depth

• Wireline derived depthmeasurement


p pe ow ere n o e o e

• M/LWD depth is commonly

referenced to this depth

of wire ran into the

hole

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• M/LWD Downhole Tool

– RealTime Clock

– Records time-based data

LWD Time Depth• M/LWD Surface unit

– Acqui res depth data

– Records time-depth

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HCIM

Pulser

Stab Pin /Pin

00:00 GR 100 API 00:00 100ft

RIGSITE


EWR4

DGR/DDS

Stab Pin /Pin

GR 100 API 100 ft


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Depth tracking

• Depth are measuredind irectl , as o osed to

direct measurement of wire

length in wi reline operation

• Depth is measured by

monitoring position of the

traveling b lock in the derrick – Block movement


– Slips status

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Sensor : Drawwork encoder • As the traveling block goes up and down the drawwork

drum containing the cable reel rotates

• Converts rotation of drawwork drum into traveling

length of the block



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Sensor : Crown Wheel

The crown wheel detects movement

of the cable on the slow sheave:

• Mounted on the crown block

• Seven inch wheel pressed against

sheave

• Requires only one calibration

• May slip on the cable


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Sensor : Air retriever • Similar working principle

with drawwork encoder

• Measures the movement

of wire connected to the

traveling block



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In-slips Switch

The in-slips switch detects when the

drillstring is in slips:

• Mounted on cable deadline

• Switch is closed when no tension oncable

• Tensioned cable = Pipe is lifted by

the block

•


movement when in slips

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Depth Calibration

• Physical measurement of

the distance of the blocktravel

• Sensor counts the rotation

of the drum

• Calibration factor

Block movement

Drum rotation signal


A A

drawworks

Calibration factor

Block movement


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Pipe Tally• Each drillpipe is of different

length

• Each join t of pipe is measured

and listed based on order of use

• Driller’s pipe tally is used as a

reference for setting the depth

system

• Accurate measurement and

tabulation of the pipe length tally


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Pipe stretch• Drillpipe stretch and compress,

this effect will become more

prominent as the well goeseeper

• The industry currently are not

yet accustomed to correct for

this effect

• No common standard to correct

for these factor is established


drilling operation


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Depth• Depth Errors

– Incorrect entry in tally sheet

– Driller used pipe out of order

– Depth sensor sl ipping

– Depth calibration error

– Inaccurate on/off bottom

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– Malfunction on the LWD RealTime clock

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Consequences

• Incorrect log depth

– Incorrect interpretation

– Completing the well at incorrect depth

– Miscalculation of formation / payzone thickness



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Questions?


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Thank YouThank You


04 hal-2011 telemetry and depth tracking f

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