MWD Signal Analysis,

Optimization and Design

Second Edition, 2018

 

 

 

by

 

Wilson C. Chin, Ph.D., M.I.T.

Stratamagnetic Software, LLC, Houston, Texas

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table of Contents

Preface, xii

Acknowledgements, xv

1. Stories from the Field, Fundamental Questions and Solutions, 1

    1. Mysteries, Clues and Possibilities, 1
    2. Paper No. AADE-11-NTCE-74, "High-Data-Rate Measurement-While-Drilling System for Very Deep Wells" significantly expanded with additional photographs and detailed annotations, 11

1.2.1 Abstract, 11

1.2.2 Introduction, 11

1.2.3 MWD telemetry basics, 13

1.2.4 New telemetry approach, 14

1.2.5 New technology elements, 16

1.2.5.1 Downhole source and signal optimization, 16

1.2.5.2 Surface signal processing and noise removal, 19

1.2.5.3 Pressure, torque and erosion computer modeling, 20

1.2.5.4 Wind tunnel analysis: studying new approaches, 23

1.2.5.5 Example test results, 42

1.2.6 Conclusions, 45

1.2.7 Acknowledgements, 46

1.2.8 Credits, 46

1.2.9 Paper references, 47

1.3 References, 48

2. Harmonic Analysis: Six-Segment Downhole Acoustic Waveguide, 49

2.1 MWD Fundamentals, 50

2.2 MWD Telemetry Concepts Re-examined, 51

2.2.1 Conventional pulser ideas explained, 51

2.2.2 Acoustics at higher data rates, 52

2.2.3 High-data-rate continuous wave telemetry, 54

2.2.4 Drillbit as a reflector, 55

2.2.5 Source modeling subtleties and errors, 56

2.2.6 Flow loop and field test subtleties, 58

2.2.7 Wind tunnel testing comments, 60

2.3 Downhole Wave Propagation Subtleties, 60

2.3.1 Three distinct physical problems, 61

2.3.2 Downhole source problem, 62

2.4 Six-Segment Downhole Waveguide Model, 64

2.4.1 Nomenclature, 66

2.4.2 Mathematical formulation, 68

2.4.2.1 Dipole source, drill collar modeling, 68

2.4.2.2 Harmonic analysis, 70

2.4.2.3 Governing partial differential equations, 71

2.4.2.4 Matching conditions at impedance junctions, 73

2.4.2.5 Matrix formulation, 74

2.4.2.6 Matrix inversion, 76

2.4.2.7 Final data analysis, 75

2.5 An Example: Optimizing Pulser Signal Strength, 79

2.5.1 Problem definition and results, 79

2.5.2 User interface, 82

2.5.3 Constructive interference at high frequencies, 83

2.6 Additional Engineering Conclusions, 85

2.7 References, 87

3. Harmonic Analysis: Elementary Pipe and Collar Models, 88

3.1 Constant area drillpipe wave models, 88

3.1.1 Case (a), infinite system, both directions, 89

3.1.2 Case (b), drillbit as a solid reflector, 90

3.1.3 Case (c), drillbit as open-ended reflector, 90

3.1.4 Case (d), "finite-finite" waveguide of length 2L, 91

3.1.5 Physical Interpretation, 91

3.2 Variable area collar-pipe wave models, 94

3.2.1 Mathematical formulation, 94

3.2.2 Example calculations, 96

3.3 References, 98

4. Transient Constant Area Surface and Downhole Wave Models, 97

Overview, 99

4.1 Method 4-1. Upgoing wave reflection at solid boundary,

single transducer deconvolution using delay equation, no

mud pump noise, 101

4.1.1 Physical problem, 101

4.1.2 Theory, 102

4.1.3 Run 1. Wide signal low data rate, 103

4.1.4 Run 2. Narrow pulse width high data rate, 105

4.1.5 Run 3. Phase-shift keying or PSK, 106

4.1.6 Runs 4, 5. Phase-shift keying or PSK, very high data rate, 109

4.2 Method 4-2. Upgoing wave reflection at solid boundary,

single transducer deconvolution using delay equation, with

mud pump noise, 110

4.2.1 Physical Problem, 110

4.2.2 Software note, 111

4.2.3 Theory, 111

4.2.4 Run 1. 12 Hz PSK, plus pump noise with S/N = 0.25, 112

4.2.5 Run 2. 24 Hz PSK, plus pump noise with S/N = 0.25, 113

4.3 Method 4-3. Directional filtering difference equation method

requiring two transducers, 114

4.3.1 Physical problem, 114

4.3.2 Theory, 115

4.3.3 Run 1. Single narrow pulse, S/N = 1, approximately, 116

4.3.4 Run 2. Very noisy environment, 118

4.3.5 Run 3. Very, very noisy environment, 119

4.3.6 Run 4. Very, very, very noisy environment, 120

4.3.7 Run 5. Non-periodic background noise, 121

4.4 Method 4-4. Directional filtering differential equation

method requiring two transducers, 122

4.4.1 Physical problem, 122

4.4.2 Theory, 123

4.4.3 Run 1. Validation analysis, 124

4.4.4 Run 2. A very, very noisy example, 126

4.4.5 Note on multiple-transducer methods, 127

4.5 Method 4-5. Downhole reflection and deconvolution at

the bit, waves created by MWD dipole source, bit assumed as

perfect solid reflector, 128

4.5.1 Software note, 128

4.5.2 Physical problem, 129

4.5.3 On solid and open reflectors, 129

4.5.4 Theory, 130

4.5.5 Run 1. Long, low data rate pulse, 132

4.5.6 Run 2. Higher data rate, faster valve action, 132

4.5.7 Run 3. PSK example, 12 Hz frequency, 133

4.5.8 Run 4. 24 Hz, Coarse sampling time, 134

4.6 Method 4-6. Downhole reflection and deconvolution at

the bit, waves created by MWD dipole source, bit assumed as

perfect open end or zero acoustic pressure reflector, 135

4.6.1 Software note, 135

4.6.2 Physical problem, 135

4.6.3 Theory, 136

4.6.4 Run 1. Low data rate run, 137

4.6.5 Run 2. Higher data rate, 138

4.6.6 Run 3. Phase-shift-keying, 12 Hz carrier wave, 139

4.6.7 Run 4. Phase-shift-keying, 24 Hz carrier wave, 139

4.6.8 Run 5. Phase-shift-keying, 48 Hz carrier, 140

4.7 References, 141

5. Transient Variable Area Downhole Inverse Models, 142

5.1 Method 5-1. Problems with acoustic impedance mismatch

due to collar-drillpipe area discontinuity, with drillbit

assumed as open-end reflector, 144

5.1.1 Physical problem, 144

5.1.2 Theory, 145

5.1.3 Run 1. Phase-shift-keying, 12 Hz carrier wave, 149

5.1.4 Run 2. Phase-shift-keying, 24 Hz carrier wave, 149

5.1.5 Run 3. Phase-shift-keying, 96 Hz carrier wave, 150

5.1.6 Run 4. Short rectangular pulse with rounded edges, 151

5.2 Method 5-2. Problems with collar-drillpipe area discontinuity,

with drillbit assumed as closed end, solid drillbit reflector, 152

5.2.1 Theory, 152

5.2.2 Run 1. Phase-shift-keying, 12 Hz carrier wave, 152

5.2.3 Run 2. Phase-shift-keying, 24 Hz carrier wave, 153

5.2.4 Run 3. Phase-shift-keying, 96 Hz carrier wave, 153

5.2.5 Run 4. Short rectangular pulse with rounded edges, 153

5.3 References, 154

  1. Signal Processor Design and Additional Noise Models, 155

6.1 Desurger Distortion, 156

6.1.1 Low-frequency positive pulsers, 158

6.1.2 Higher frequency mud sirens, 159

6.2 Downhole Drilling Noise, 162

6.2.1 Positive displacement motors, 163

6.2.2 Turbodrill motors, 164

6.2.3 Drillstring vibrations, 164

6.3. Attenuation Mechanisms, 166

6.3.1 Newtonian model, 166

6.3.2 Non-Newtonian fluids, 167

6.4 Drillpipe Attenuation and Mudpump Reflection 169

6.4.1 Low-data-rate physics, 170

6.4.2 High data rate effects, 171

6.5 Applications to Negative Pulser Design in Fluid Flows and to

Elastic Wave Telemetry Analysis in Drillpipe Systems, 172

6.6 LMS Adaptive and Savitzky-Golay Smoothing Filters, 174

6.7 Low Pass Butterworth, Low Pass FFT and Notch Filters, 176

6.8 Typical Frequency Spectra and MWD Signal Strength Properties, 177

6.9 References, 178

7. Mud Siren Torque and Erosion Analysis, 179

7.1 The Physical Problem, 179

7.1.1 Stable-closed designs, 181

7.1.2 Previous solutions, 181

7.1.3 Stable-opened designs, 183

7.1.4 Torque and its importance, 184

7.1.5 Numerical modeling, 185

7.2 Mathematical Approach, 185

7.2.1 Inviscid aerodynamic model, 187

7.2.2 Simplified boundary conditions, 188

7.3 Mud Siren Formulation, 190

7.3.1 Differential equation, 190

7.3.2 Pressure integral, 191

7.3.3 Upstream and annular boundary condition, 192

7.3.4 Radial variations, 194

7.3.5 Downstream flow deflection, 195

7.3.6 Lobe tangency conditions, 196

7.3.7 Numerical solution, 196

7.3.8 Interpreting torque computations, 197

7.3.9 Streamline tracing, 198

7.4 Typical Computed Results and Practical Applications, 200

7.4.1 Detailed engineering design suite, 200

7.5 Conclusions, 206

7.5.1 Software reference, 206

7.6 References, 207

8. Downhole Turbine Design and Short Wind Tunnel Testing, 208

8.1 Turbine Design Issues, 208

8.2 Why Wind Tunnels Work, 210

8.3 Turbine Model Development, 213

8.4 Software Reference, 217

8.5 Erosion and Power Evaluation, 222

8.6 Simplified Testing, 225

8.7 References, 228

9. Siren Design and Evaluation in Mud Flow Loops and Wind Tunnels, 229

9.1 Early Wind Tunnel and Modern Test Facilities, 230

9.1.1 Basic ideas, 231

9.1.2 Three types of wind tunnels, 232

9.1.3 Background, early short wind tunnel, 233

9.1.4 Modern short and long wind tunnel system, 234

9.1.5 Frequently asked questions, 237

9.2 Short wind tunnel design, 240

9.2.1 Siren torque testing in short wind tunnel, 244

9.2.2 Siren static torque testing procedure, 247

9.2.3 Erosion considerations, 250

9.3 Intermediate Wind Tunnel for Signal Strength Measurement, 251

9.3.1 Analytical acoustic model, 252

9.3.2 Single transducer test using speaker source, 255

9.3.3 Siren Dp procedure using single and differential

transducers, 255

9.3.4 Intermediate wind tunnel test procedure, 257

9.3.5 Predicting mud flow Dps from wind tunnel data, 261

9.4 Long Wind Tunnel for Telemetry Modeling, 263

9.4.1 Early construction approach - basic ideas, 263

9.4.2 Evaluating new telemetry concepts, 268

9.5 Water and Mud Flow Loop Testing, 268

9.5.1 Real-world flow loops, 269

9.5.2 Solid reflectors, 271

9.5.3 Drillbit nozzles, 272

9.5.4 Erosion testing, 273

9.5.5 Attenuation testing, 274

9.5.6 The way forward, 275

9.6 References, 276

  1. Advanced System Summary and Modern MWD Developments, 277
  2. 10.1 Overall Telemetry Summary, 278

    10.1.1 Optimal pulser placement for wave interference, 278

    10.1.2 Telemetry design using FSK, 281

    10.1.3 Sirens in tandem or "sirens in series," 283

    10.1.4 Attenuation misinterpretation, 284

    10.1.5 Surface signal processing, 288

    10.1.6 Attenuation, distance and frequency, 291

    10.1.7 Ghost signals and echoes, 294

    10.2 Sirens, Turbines and Batteries, 295

    10.2.1 Siren drive, 295

    10.2.2 Turbine-alternator system, 295

    10.2.3 Batteries, 296

    10.2.4 Tool requirements, 297

    10.2.5 Design trade-offs, 298

    10.3 References, 299

     

  3. MWD Signal Processing in China, 300
  4. Sensor Developments in China, 318
  5. 12.1 DRGDS Near-bit Geosteering Drilling System, 318

    12.1.1 Overview, 318

    12.1.2 DRGDS tool architecture, 319

    12.1.3 Functions of DRGDS, 327

    12.2 DRGRT Natural Azi-Gamma Ray Measurement, 332

    12.3 DRNBLog Geological Log, 336

    12.4 DRMPR Electromagnetic Wave Resistivity, 338

    12.5 DRNP Neutron Porosity, 339

    12.6 DRMWD Positive Mud Pulser, 343

    12.7 DREMWD Electromagnetic MWD, 344

    12.8 DRPWD Pressure While Drilling, 347

    12.9 Automatic Vertical Drilling System DRVDS-1, 350

    12.10 Automatic Vertical Drilling System DRVDS-2, 354

  6. Sinopec MWD Research, 355
  7. 13.1 Engineering and Design Highlights, 356

    13.2 Credits, 364

  8. Gyrodata MWD Research, 365
  9. 14.1 Short and Long Wind Tunnel Facilities, 366

    14.2 Credits, 375

  10. GE Oil & Gas MWD Developments (BakerHughes, a GE Company), 376

15.1 Recent Patent Publications, 377

15.2 Credits, 391

15.3 References, 391

16. MWD Turbosiren - Principles, Design and Development, 392

16.1 Background and Motivation, 392

16.1.1 Mud siren background, 393

16.1.2 Enter the turbosiren, 398

16.1.3 General unanswered questions, 404

16.2 Prototype Turbosirens and Experimental Notes, 405

16.2.1 Single-stage turbosiren, 405

16.2.2 Basic measurements, 406

16.2. 3 Dual-stage turbosiren, 409

16.2.4 Three-stage turbosiren, 410

16.2.5 Complementary reference turbine, 411

16.2.6 Turbosiren assemblies, 412

16.2.7 Turbosiren fabrication, 414

16.2.8 Test matrix, changing lobe number and taper, 415

16.3 Pressure Measurement - Subtleties and Ideas, 416

16.3.1 Physical discussion, 416

16.3.2 Test Series A - "Sirens in series" signal augmentation, 419

16.3.3 Test Series B - Rotor taper effects on RPM and Delta-P, 423

16.3.4 Test Series C - Reference axial turbine, 429

16.4 Credits, 438

16.5 References, 439

17. Design of Miniature Sirens,440

17.1 Siren flowmeter applications, 441

17.2 Mini-siren prototypes, 442

17.3 Cardboard test prototyping, 448

17.4 Credits, 450

 

18. Wave-Based Directional Filtering, 451

18.1 Background, 451

18.2 Theory and Difference-Delay Equations, 452

18.3 Calculated Results, 455

18.3.1 Method 4-3, Difference equation

(Software reference, 2XDCR07D.FOR), 456

18.3.2 Method 4-3, Difference equation

(Software reference, 2XDCR07E.FOR), 460

18.3.3 Method 4-3, Difference equation

(Software reference, 2XDCR07F.FOR), 463

18.3.4 Method 4-4, Differential equation (Software reference,

SAS14D.FOR Option 3 identical to SIGPROC-1.FOR), 466

18.4 Conclusions, 472

18.5 References, 472

 

Cumulative References, 473

Index, 478

About the Author, 489