SPE MS New Instrument Performance Models for Combined Wellbore Surveys Facilitate Optimal Use of Survey Information

Transcription

1 SPE MS New Instrument Performance Models for Combined Wellbore Surveys Facilitate Optimal Use of Survey Information Adrián Ledroz, Jon Bang, John Weston 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

2 SPE MS Presented at the IADC/SPE Drilling Conference and Exhibition Fort Worth, Texas, 1-3 March 2016 Accepted for publication in SPE Drilling & Completion 2 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

3 Jon Bang, PhD Development Engineer Experience - Gyrodata Since Petroleum Research Since 1991 Speciality - Wellbore Positioning - Survey Quality - Position Uncertainty Analysis 3 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

4 Founded in 1980, Houston, Texas Globally positioned to support a wide range of markets - Operating in +80 countries, with +47 locations - Customer base of +625 Customers Deliver precision wellbore placement & investigation solutions for drilling, completions, and production challenges - Drilling Services: Performance Motors, RSS, MWD, LWD - Wellbore Surveying: Gyro, GWD, Conventional Systems - Production Logging: MicroGuide, CBL, Caliper, Magnetic Thickness Detection 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

5 CONTENTS Slide 5 Introduction / Challenge Solution Results Conclusions 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

6 BENEFITS OF MULTIPLE SURVEYS 6 Mutual quality check and validation Weighted average gives optimal position estimate Weighted average gives minimum position uncertainty 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

7 TWO ASSUMPTIONS 7 The surveys must have passed standard quality tests - No gross errors The surveys must be interpolated to common MD 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

8 ERROR ANALYSIS PROCEDURE Slide 8 Single Survey Analysis Weighted Average Of Multiple Surveys: (Chia Et Al., 2003) V V True Averaged Wellbore directional data Averaged IPM file Survey reporting software Error model software (ISCWSA) Averaged Wellbore positions Averaged Position uncertainties Averaged positions True Averaged position uncertainties (single survey results)

9 IPM FILE EXAMPLE IPM = «Instrument Performance Model» = Description of surveying tool s accuracy Slide 9 MWD tool Fixed format table Contents vary according to surveying tool Averaged IPM = Add another IPM model; add weighting factors to tune the output

10 AVERAGED IPM FILE REQUIREMENTS Slide 10 Results close to true average - Conservative Any combination of tools and range of uncertainties Any wellbore profile Any number of surveys Practical algorithm - Systematic approach - Easy implementation, automation

11 Slide 11 STEP 1: IDENTICAL ERROR TERMS Correlated: Keep the one with smallest magnitude Uncorrelated: Keep one, with improved magnitude

12 STEP 2: WEIGHTING FACTORS w 1, w 2 Slide 12 Error source groups in IPM: D, I, A (need individual weights) Standard error analysis N, E, V uncertainties (not suited as weights in DIA system) Conversion to DIA-like system

13 AH-HS-Lat SYSTEM IS LOCAL => WEIGHTS ARE APPROXIMATE Slide 13 Survey 1 Survey 2 Lat Lat Lat s 2 Lat Largest values are used for weighting factors MD Lat Lat MD

14 STEP 3: ADJUSTMENT FACTORS B D, B I, B A Slide 14 Problem True average may be under-estimated True Initial average Solution Ellipsoid orientations are approximately equal B D, B I, B A = ratio of ellipsoid axes Magnify w A1 and w A2 by B A, etc. Update => final averaged IPM file

15 AVERAGED IPM FILE, CASE 1 Slide 15 Depth Misalign. Sag MWD STEP 2 Weighting factors w I,MWD w A,MWD w I,gyro w A,gyro STEP 1 Identical terms are combined Cont. gyro STEP 3 Adjustment factors B D B I B A

16 CASE 1: Inc = 0-30 o, N-S Slide s ellipses x10: Survey 1 = MWD Survey 2 = cont. gyro True average IPM average

17 CASE 2: NEAR HORIZONTAL, N-S Slide s ellipses x10: Survey 1 = MWD Survey 2 = GWD True average IPM average s reduction: 16% 28%

18 CASE 3: NEAR HORIZONTAL, E-W Slide s ellipses x10: Survey 1 = MWD Survey 2 = cont. gyro True average IPM average

19 CONCLUSIONS: AVERAGING METHOD 19 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 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

20 CONCLUSIONS: BENEFITS OF AVERAGING One survey data set per wellbore Optimal wellbore positions + improved accuracy Optimise 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 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

21 Slide 21 ACKNOWLEDGEMENTS Erik Nyrnes, Statoil Gyrodata Inc. 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section

22 Thank you 44 th General Meeting September 22 nd, 2016 Glasgow, Scotland, UK Wellbore Positioning Technical Section