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ISCWSA

Recap &

Introduction

What is ISCWSA

2

The Industry Steering Committee on Wellbore Survey Accuracy

SPE WPTS – Wellbore Positioning Technical Section

Mission Statement

"The primary aim of this group is to produce and maintain standards for the industry relating

to wellbore survey accuracy.“

"To set standards for terminology and accuracy specifications. Establish a standard

framework for modelling and validation of tool performance. Raise awareness &

understanding of wellbore survey accuracy issues across the industry."

Who Can Join

3

Anyone is free to attend any ISCWSA meetings.

This includes but is not limited to

• Well Planners

• Coordinators

• Field Hands

• Software Developers

• Tool Manufacturers

• Drilling Engineers

• Technology Companies

• People with General Interest in Survey Accuracy

• All

Meetings

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Meetings are held twice a year.

One meeting has to be held in conjunction with SPE ATCE

Next Meeting TBD

Previous Meeting

Last Week Glasgow, Scotland

Subcommittee Meetings

5

Meetings are held the normally the day before.

Sub committee meeting are open to all.

• Well Intercept

• Error Model Management

• Collision Avoidance

• Operator’s Wellbore Survey Group

• Education

Attendees are those who can contribute to that specific group. (Voluntary Work)

Directors and Chairs

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Chair Person: Son Pham, ConocoPhillips

Program Chair: Jonathan Lightfoot, Occidental Oil and Gas Corporation

Secretary Chad Hanak, SuperiorQC

Treasurer: Robert Wylie, NOV

Webmaster: Phil Harbidge, Schlumberger

Director at large: Carol Mann, Dynamic Graphics Inc.

Director at large: Andy McGregor, Tech21

Well Intercept Roger Goobie, BP

Error Model Management Andy McGregor, Tech21

Collision Avoidance Steve Sawaryn

Operator’s Wellbore Survey Group Pete Clark, Chevron

Education Steve Mullin

Recap

Keynote Address

6 Technical Presentations

Guest Speaker

5 Sub-Committee Updates

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888

TECHNICAL PRESENTATIONSSwarm Satellite Data to Improve Global Geomagnetic Reference

Modelling

Ciarán Beggan, British Geological Survey

Technical Presentations

Swarm Satellite Data to Improve Global Geomagnetic Reference Modelling

– Ciarán Beggan, British Geological Survey

Earth’s Magnetic Environment

ESA Swarm Mission

Secular Variation: Jerks, IGRF, and Model Updates

Modelling Uncertainties

Summary

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10

Earth’s Magnetic Field

Dominant core field varies over

months to years (±60,000 nT)

Fields due to complex current

systems in the ionosphere and

magnetosphere vary from

seconds to years (±60 nT)

Localised crustal field stable

through time (±10 nT)

Now resolving ocean tides

induced fields (±2 nT)

Credit: GFZ,DTU

ESA Swarm Mission

Novel 3-satellite constellation

– 2 lower satellites

– 1 in higher orbit

Gradient data calculated as difference between two nearby measurements

15-50 second separation along track

Sensitive to local, small scale features

Uses ground observatory data

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Secular Variation

Flow of liquid iron core generates

secular variation at surface

Non-linear and constantly

changing (‘jerks’)

Current research to improve

understanding

Jerks, IGRF and Importance of Model Updates

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Due to 2014 jerk, IGRF-12 prediction is 15.7 nT RMS different from recent core field model 2016

IGRF-12

Prediction

s

Summary

Annually updated models necessary to counter large and

unpredictable rapid changes from Earth’s core

Uncertainties are lowering but care needed not to

misunderstand what global models can do

Swarm is promptly delivering a large quantity of highly

accurate measurements

Swarm gradient data offers unique global resolution of

small scale field, especially as orbit lowers

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151515

TECHNICAL PRESENTATIONSNew Instrument Performance Models for Combined Wellbore

Surveys Facilitate Optimal Use of Survey Information

(SPE – 178826 – MS)

Jon Bang, Gyrodata

New Instrument Performance Models for Combined

Wellbore Surveys Facilitate Optimal Use of Survey

Information (SPE – 178826 – MS)

– Jon Bang, Gyrodata

Introduction/Challenge

Solution

Results

Conclusions

16

Technical Presentations

Benefits of Multiple Surveys

Mutual quality check and validation

Weighted average gives optimal position estimate

Weighted average gives minimum position uncertainty

Two Assumptions

– The surveys must have passed standard quality tests

• no gross errors

– The surveys must all be interpolated to common MD’s

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Error Analysis Procedure

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Case 1: Incl = 0-30°, N-S

Case 3: Near Horizontal, E-W

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CONCLUSIONS: AVERAGING METHOD

Individual surveys must pass QC routines: no gross errors

Algorithm– D, I, A weighting factors + adjustment factors

– Analytic, no iteration, suited for automation

Results– Close to true average, conservative

– Any tools, any uncertainties

– Any wellbore profile; best accuracy in tangential sections

– Any number of surveys

Possible challenges– Validation of method for different well profiles

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CONCLUSIONS: BENEFITS OF AVERAGING

One survey data set per wellbore

Optimal wellbore positions + improved accuracy

Optimize survey programs

Improved reliability of anti-collision calculations

May turn unfeasible projects into achievable ones

– Small drilling targets

– Long extended reach wells

– Highly congested fields

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232323

TECHNICAL PRESENTATIONSMagnetic Mud

Giorgio Pattarini, University of Stavanger

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Magnetic Drilling Mud

When the mud is contaminated by

magnetic materials, it becomes

magnetic

Alters the geomagnetic field

around the MWD

Induces an error in magnetic

measurements

Known for 20 years

Still a lot of gaps in understanding

and predicting the error

Image: physics.stackexchange.com

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Occurrence

Only when doing a magnetic survey

Magnetic components

– Limenite

– Hematite

– Contamination

Heavily used mud

High latitudes enhances the error

Size of the error:

– 2.7% attenuation of the

magnetic field

(SPE87169)

– 0.24° Azimuth error

(OMAE 2016 – 54044)

Gaps

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Offcenter magnetic

field

Particles are

magnetic dipolesSettling at high

inclinations

Complex correlation

between concentration and

magnetic susceptibility

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Current Practices

Ban magnetic ingredients in mud

Use ditch magnets

Measure with pumps on

Magnetometer centered in MWD tool

Run a gyro

Analyze the mud after drilling the well

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Summary

Magnetic mud affects the

magnetic survey

Base Model: predictable cross-

axial attenuation

– Difficult to apply

– Not included in tool error model

Some practices in place to

mitigate and avoid problem

Questions:

– Is the issue worth further

research?

– Why has the first model

not been applied?

– Are the current practices

effective enough?

Proposed Research Project

Model the mud susceptibility for ingredients/contaminents

Mud in dynamic vs static conditions

Effectiveness of ditch magnets

Targets

Be able to estimate error induced by magnetic mud

Be able to remove bias induced by magnetic mud

Improve usefulness of current practices

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303030

TECHNICAL PRESENTATIONSNew Advances in Geomagnetic Modelling

Patrick Alken, NOAA/NCEI

New Advances in Geomagnetic Field Modelling

– Patrick Alken, NOAA/NCEI

Introduction

Disturbance Field Correction (Magnetosphere)

Disturbance Field Correction (Ionosphere)

EMAG2 Crustal Grid Update

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Technical Presentations

Introduction

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Disturbance Field from Magnetosphere

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Magnetospheric Current Systems

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Solar Forecasting with Satellite Data

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Real-time Prediction of Magnetospheric Fields

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Disturbance Field from Ionosphere

±80 nT Variaions 100-200 nT Variations

Storm Measurements

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MWD Calibration

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MWD with HDGM

- Fixed reference

MWD with

HDGM-RT+DIFI

- Variable reference

- Better fit

Data provided by Schlumberger

EMAG2 Crustal Grid Update

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Primary source of data

comes from marine and

airborne tracklines

• Over 100 institutions

• Over 50 years

• 3255 surveys

• 75.9 million data points

• 10.5 million miles

• Precompiled grids over

continental areas

• Provided by Governments,

Industry, and Academia

Send Us Your Data!

More data will enable a more detailed grid and more

accurate crustal field models

NOAA can offer long-term archival

Data can be flagged as private/proprietary (not for public

download); we currently archive proprietary data

Even decimated / lower-resolution datasets would be

useful

Contact us at geomag.models@noaa.gov

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424242

TECHNICAL PRESENTATIONSA New Approach to MWD Calibration to Improve Accuracy and

Reduce Calibration Time

Angus Jamieson, University of the Highlands and Islands

New Approach Objectives

Avoid orthogonality issues

Allow more sensors to be used

Make calibrations more accurate

Speed up calibration process

Improve MWD accuracy

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Reference Angles

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For Example

T W

X 0 90

Y 90 90

Z 0 0

Calibration to References

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Find the 2 alignments for each sensor

– Alignment from along hole axis W

– Alignment from high side axis T

Include all sensors available in the tool

Calibrate each sensor’s 2 alignments vs

temperature using a ‘hot’ tumble and a ‘cold’

tumble

– Use a linear interpolation for W & T at all

other temperatures

Calibration to References

Using actual alignments corrected at each temperature

– Set tool to Incl 60°, Azm 0°, Tool Face -45°, heat to 150°C and record while cooling

– Set tool to Incl 120°, Azm 180°, Tool Face 135°, heat to 150°C and record while cooling

– Determine least squares best fit polynomials to correct for scale and bias

In instrument firmware, use temperature corrected sensor data and actual alignments to produce synthetic 3-axis perfectly orthogonal data for surveys

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Further Information

Detailed mathematics and procedure are in presentation

Program is available from Angus for calibrations of both

magnetometers and accelerometers

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Advantages

Much shorter calibration time

Greater accuracy in the result

Uses all available sensors in the calculation of angles

Same process regardless of the number of sensors

Same output (perfectly orthogonal raw data or Incl, Azm,

and Tool Face)

No change to field procedures

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494949

TECHNICAL PRESENTATIONSEast-West Exclusion Zones:

Why Do We Have Them and How Can We Eliminate Them?

Chad Hanak, Superior QC

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Why Exclusion Zones?

Problem with Drilling East/West

Axial Magnetic Interference

(AMI)

50% more error than Declination

Available Corrections

Single Station Correction (SSC)

Multi-Station Analysis (MSA)

Problems with the Corrections

Multiple solutions

Degraded accuracy

Exclusion Zones for Horizontal Wells

Existing Standards

(SPE 125677)

BGGM

– 0.82 > sin(I)*sin(Az)

– ±35° from East/West

IFR1

– 0.91 > sin(I)*sin(Az)

– ±25° from East/West

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BGGM Exclusion Zone

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Multiple Solution Problem: SSC

Single Station Correction

Bx and By are measured

Bx and By are modeled as a

function of Azm using

– Reference Bt & Dip

– Measure Incl & TF

Minimum distance between

model and measurement is

found

(Bx, By) as a Function of Azm

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Multiple Solution Problem: SSC

Single Station Correction

Bx and By are measured

Bx and By are modeled as a

function of Azm using

– Reference Bt & Dip

– Measure Incl & TF

Minimum distance between

model and measurement is

found

Distance from Measured to Model

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Multiple Solution Problem: SSC

How to handle?

Consider the uncertainty in

– Reference Bt

– Reference Dip

– Measured Incl

– Measured TF

Multiple Minima inside 3σ Uncertainty

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Multiple Solution Problem: SSC

How to handle?

Consider the uncertainty in

– Reference Bt

– Reference Dip

– Measured Incl

– Measured TF

Map onto χ2 test

– Reject any minima w/probability of

occurance < 0.1%

If there are still multiple minima

– the solution cannot be trusted

Multiple Minima inside 3σ Uncertainty

Multiple Solution Problem: SSC

BUT

– If only 1 solution is

probabilistically plausible

– Okay to move forward with a

valid solution

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Distance as χ2 Statistic

Multiple Solutions: MSA

SSC was the EASY version

MSA similar – Multiple solutions can exist

– MSA does NOT automatically replace SSC in exclusion zone

– Variation in wellbore direction CAN resolve

– Required AMOUNT of variation is situation dependent

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Degraded Accuracy

SSC

Correction not as accurate as standard MWD IPM near East/West

Specific IPM derived to model accuracy of correction (+AX)

Accounts for effects of magnetic reference field errors

MSA

+MS error model does not model the accuracy of MSA corrections

No published requirements to check for valid use

Best Option: Calculate accuracy directly for chosen solution

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Drilling Safely East/West

If AMI corrections are required:

Check for multiple solutions

Ensure IPM assigned to

corrected surveys does not

overstate accuracy

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MSA Exclusion Zone for Horizontal Wellbores: ±15°

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Eliminating the Exclusion Zone

Including part of the build in the

lateral:

Start lateral at 80° Inclination

– Exclusion zone is ±5°

Start lateral at 70° Inclination

– Exclusion zone is eliminated

MSA Exclusion Zone with part of build included in lateral

Conclusions

Axial Magnetic Interference (AMI) creates large azimuthal errors when drilling East/West

SSC & MSA have problems

– Multiple solutions

– Degraded accuracy

Can reduce ±35° exclusion zone by

– Checking probabilistic plausibility of extra solutions

– Validating target IPM against calculated accuracy of corrections (MSA)

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E-Book & Course

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E-book

http://www.uhi.ac.uk/en/research-enterprise/wellbore-positioning-

download

Editorial Mangers:

David Gibson – Lodestar International

Carol Mann – DGI Graphics

Angus Jamieson – Univ Highlands and Islands

Steve Mullin – Independent

Robert Long – Baker Hughes

Links

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Website OFFICIAL

www.ISCWSA.NET

SPE

http://connect.spe.org/wellborepositioning/home

LinkedIn- Open forum for discussion with industry leaders

http://connect.spe.org/WellborePositioning

If you would like to be added to the ISCWSA e-mail distribution list please contact

Chad Hanak, ISCWSA Secretary on:

chad@superiorqc.com

646464

Thanks!

Let’s Get Drilling.