Further reading

Anstey, N.A. 'Whatever happened to ground roIl?'. Leading Edge 05-03-0040. Barbier, M.G. 'Mini-SOSIE for Land Prospecting'. Geophysical Prospecting, 24-03-

0518. Barbier, M.G. 'Pulse Coding in Seismic Prospecting - SOSIE and SEISCODE'.

Geophysical Prospecting, 22-01-0155. Barbier, M.G. 'SOSIE - a New Tool for Marine Seismology'. Geophysics, 38-04-

0673. Evenden, B.S., Stone, D.R. and Anstey, N.A. (1971) Seismic Prospecting Instruments

(2 vols). Gebruder Borntraeger. Telford, W.M., Geldart, L.P., Sheriff, R.E., Keys, D.A. (1976) Applied Geophysics,

Cambridge University Press, Cambridge. Waters, K.H. (1987) Reflection Seismology, John Wiley, Chichester. Ziolkowski, A. 'A simple approach to high resolution seismic profiling for coal'.

Geophysical Prospecting, 27-02-0360. Ziolkowski, A. 'Seismic vital in coal mining'. Leading Edge, 01-02-0033.

Glossary

3-D Three-dimensional. 3-D survey A survey in which the result is a volume of seismic data; the CDP

stacked traces comprise samples from different distances and directions, and cross-sections of the volume may be viewed in space or time.

Aliasing Frequency ambiguity resulting from the sampling process in which the level of a continuous analog signal is measured at discrete intervals of time, i.e. is digitized.

Analog A continuous physical variable, e.g. voltage, which bears a direct rela­tionship to another, e.g. the motion of the earth.

Anti-alias filter A filter used on an analog, before sampling, to remove frequen­cies which could pass through aliasing.

Attack rate The time required for the voltage of a system under automatic gain control (AGC) to return to 63% of its steady-state value.

Autocorrelation The correlation of a waveform, i.e. a seismic trace, with itself. Autocorrelogram A display of the autocorrelation function of a seismic trace. Automatic gain control A system in which the output amplitude is used for

the automatic control of the gain of an amplifier. A-D converter A device that converts the voltage of an analog signal to a

digital binary number. Binary number A number to the base 2; 0 and 1 are the only digits used in

the binary system. Brute attack A first version of a CDP stack in which only crude values for

static and dynamic corrections have been applied. Cache basket A basket suitable for use with a long-line attached to a helicopter;

used for transporting field material, e.g. geophones, cable, explosives. CDP gather A set of seismic traces having the same common depth point. Contour map A map showing lines of equal time or depth. Convolution Change in a waveshape as a result of passing through a linear

filter such as the earth. Correlation The technique of measuring the degree of similarity between two

time functions; may be between two seismic traces or between the pilot vibrator sweep and the resulting uncorrelated seismic record.

Coupling The contact of a geophone with the ground; it acts as a form of filter. Cuttings The material extracted during the drilling of a hole in the ground. Deconvolution A process to restore a waveshape to the form it had before it

passed through a linear filter; also known as inverse filtering.

358 Glossary

Delay time In refraction work, the extra time needed to travel along a raypath over the time needed to travel the same horizontal distance at the highest velocity met within the raypath.

Demultiplex To separate the individual component channels that have been multiplexed.

Differential moveout The difference in arrival times at adjacent geophone arrays or between the extreme geophones of an array.

Diffraction The bending of wave energy around obstacles without obeying Snell's law, as explained by Huygens' principle.

Digital Representation and manipulation of information in the form of discrete numbers.

Direct wave The energy travelling from a shot to a geophone along the surface of the earth.

Dynamic range The range of a system within which signals can be recovered without distortion.

Filter A part of a system that discriminates against some of the information entering it.

Fixed point A number in which the decimal point is fixed; may also imply integer operations.

Floating point Standard notation, e.g. 1.250 x 105.

Flow line A small diameter pipeline connecting a well-head to a collecting station.

Geophone spread 1. All the geophone arrays connected to the recording truck. 2. The arrangement of the set of geophone arrays being used for each shot.

Inertial switch One in which contact is made when the unit comes to an abrupt halt.

Initiation time In electrical detonators, the time between the current passing through the detonator and the actual explosion.

Intercept time The time obtained by extrapolating the refraction alignment on a T-X plot back to zero offset.

Interpretation 1. The analysis of seismic records, either individual or stacked sections. 2. The creation of a geologic model that is in agreement with observed data.

Interval velocity The average velocity within the sub-surface material between two reflections.

Leakage Low electrical resistance to ground where it should be high; a source of noise.

Long-line In helicopter work, a cable that is connected to the load to be trans­ported.

Match filter A filter designed to remove the difference between the effects of two different types of source.

Multiplex The sampling and storing, in sequence, of the output of each of a set of geophones during one time-sampling cycle.

Noise train The appearance of source-generated coherent noise as it traverses a seismic record.

Notch filter A filter designed to remove a narrow band of frequencies. Commonly used to remove pickup from power lines.

Observer The person in charge of the actual recording of seismic data. Octal binary A number to the base 8, with each of its digits written in binary

format. Phase 1. The angular lead or lag or a sine or cosine wave with respect to a

referent. 2. Loosely, the recurrence of a sinusoidal event.

Glossary 359

Picking times The identification and timing of an event on a seismic record, usually associated with refraction and uphole records.

Pulse test A test of the recording system in which a very short pulse of known amplitude and polarity is input to the system.

Raster block Used in electrostatic cameras to transfer data in lines as opposed to complete characters.

Reflection The energy, or waveform, reflected from an acoustic boundary. Refraction The change in direction and velocity of a seismic ray passing from

one medium into another. Response 1. The output of a system after a given event has entered it. 2. A

measure of the filtering action of the system. Shooter The person in charge of explosives. Sign-bit recording Recording that ignores the amplitude of a signal and records

only whether it is positive or negative. Slip-face The loose scree slope on the lee side of a sand-dune. Stack A composite record made by combining corresponding traces and

samples from different records. Time break 1. The time at which a seismic wave was generated. 2. A mark on

a seismic record that indicates the instant of a shot. Traverse In topographical surveys, a series of connected observations. Waveform A plot, in time, of a quantity associated with wave motion, e.g.

voltage, seismic displacement.

Index

Page numbers in bold refer to figures.

3-D and crooked line stack 342 3-D bin 197, 346

density 197 distribution of traces 197

3-D program 182, 184 3-D shotpoint 182, 183 3-D surveys 9, 16, 182, 185, 191, 342

control 191, 192 design 191, 192 field processing 184 line spacing 184 shotpoint 182, 183 swath 182, 184

Absorption by earth 17 Academic tests 271 Access 61, 198, 214, 243, 284

alternative routes 198 diagrams 205, 206, 206 hazard 204, 205 inaccessibility 85

Acoustic boundaries 72 see also Horizon

Acquisition 18 Ad hoc tests 194, 271, 274

academic 194 client's cost 278, 279 contractor's cost 274-7 no loss of production 279, 280

AGe, see Automatic Gain Control Agreement 4 Agreements for access 210

Air shots 19, 53, 223, 284, 301, 314 Airgun 57, 160, 174 Airwave 55, 74, 115,223

comparison 55, 55 cross-feed 91, 91, 115, 116

Ambient noise 79, 89, 116, 320, 354 level 83, 84, 115

Ammonium nitrate 222 primer charge 222

Amplifier 39, 47, 83, 314, 315 Amplitude equalization 294 Amplitude response 306 Analog 19, 38, 83, 97, 186, 315 Analog computers 186, 187 Analog recording 320, 326 Analog systems 49 Analog-to-digital 27, 47

converter 27, 39, 47, 82 Angle of incidence 73 Anstey, N.A. 31, 155 Anti-alias filter 81, 294 Anti-personnel mines 213 Anti-tank mines 213 Apparent frequency 294 Apparent velocity 294 Apparent wavelength 294 Arctic zone 228, 232 Areal arrays 192, 303, 305, 313 Areal distribution 79 Army 221, 222 Array response 306, 307-12, 313 Array response program 192, 313

Index 361

Arrays 19, 25, 83, 90, 120, 191,283, 303

centre 128 comparison 292 dimensions 128, 294 duplication 90, 277 four vibrators 128, 129, 132-4, 142 geometry 128, 192, 281, 284 modification 120 normal 120, 121 placement of elements 119 response 126, 127, 135, 138, 141,

309-12 shortened correctly 120, 123-5, 126 shortened incorrectly 120, 122 source 128, 142 template 119 three vibrators 128, 130, 136, 137,

139,140 total area 142 vibrator 308

Arrival times 158, 168, 178 Asymmetrical spread 334 Attack rate 22

see also Automatic Gain Control; Gain setting

Attenuation 335 coherent noise 335 extraneous noise 350 multiple reflections 335

Attributes of the playback 108-17 Autocorrelogram of sweep 113 Automatic Gain Control (AGC) 22, 26

playback 98, 98, 274, 275 see also Gain; Gain setting

Automatic interpretation 339, 340 Auxiliary channels 22, 50, 112, 113 Average velocities 181 Average velocity 90, 173, 318, 294

function 196 A-to-D converter, see Analog-to­

digital

Back crew 242 see also Pickup crew

Background noise 17 Badlands 217, 226 Barbier, M.G. 350 Base camp 187 Base of weathering 156, 196

Base Wx 156 Baseplate reference 152 Bends in seismic line 326 Bin 346

see also CDP bin, 3-D bin Binary number 47 Birddog I, 188, 198, 228, 243

activities 6, 8 employment 62 personnel supervision 235, 236 responsibilities 5, 13, 13, 70, 71 vigilance 146, 222

Bits 48 Blaster 142, 149, 151 Boosters 82, 82 Bribery 210 Brush 223, 224 Brute stack 190 Buffer 50 Buggies 229 Bulk correction 173 Bulldozed lines 30, 128, 215, 217, 253 Bulldozers 4, 61, 65, 71, 258

minimum distance from spread 94 need 243

Bulldozing cost 214, 284 cutting access 218 damage 216 noise 216 rate of cutting 214

Bulldozing log 253

Cable crew 31, 236, 240, 242 Cables 19, 31,39,42, 45, 149

calibrated 160 fibre-optic 90 hermaphroditic 41 interconnecting 41 part of the trace 82, 82

Camera 100, 104, 105, 314, 315 attenuation 101, 102, 103, 111 speed 104, lOS, 106, 106, 108 trace separation 105, 107

Camera facilities 187 Camp 30, 65, 66-8, 71, 146

mine clearance 212 vehicle park 65

Camp boss 236, 239 Campsite 243

362 Index

Cams 24 Case study 294, 297, 295-300, 301 Casing: metal, plastic 159, 161, 175,

219 CDP 33, 197, 314

configuration 320 coverage 12, 42, 84, 245 distribution 78 fold of coverage 76, 78, 79 gather 196, 341 horizontal distance 345 number 326 processing 193, 195 reciprocal travel path 334 recording 16, 25, 186, 196, 318 stacked trace 320 sub-surface samples 320 sub-surface spacing 77, 320 three-fold coverage 25, 26 3-D 16, 184

CDP bin 345, 346 CDP cable 38, 42, 42, 320

diagram 42, 44 CDP sets 337 CDP stack 78, 157, 190, 195, 349

errors in CDP switch position 114 skipped shotpoints 84 spatial resolution 342

CDP switch 39, 45, 46, 82, 82 in 3-D 182

CDP switch position 106, 108, 113, 193 errors in 114, 326

CDP traces 337 Changes in data quality 271 Channels 45, 48 Charge 52, 301 Civil engineering 158, 283, 348 Clamping geophone 175 Client I, 4, 17, 144, 243 Client's cost (tests) 278, 279 Client's representative 1 Climate 6

economic 6 political 6

Clipping 23, 27, 100, 101, 101 CMP 314

see also CDP Coherence of events 17 Coherent noise 24, 102, 283, 284, 335,

339

see also Shot-generated noise; Source-generated noise

Column charge 160 Common depth point 314

see also CDP Common offset stack 196, 337, 338,

339 Common reflection point 85

see also CDP Computer 18, 25

analog 25 digital 18 see also Digital computers

Concession 7 see also Lease

Connectors: cables, plugs 82, 82 Constant velocity stacks 340 Consultants 188 Continuity 17, 149, 154, ISS, 242, 337 Contour map 10, 12, 23, 61 Contractor I, 4, 11, 13, 144 Contractor's cost (test) 274-7 Control points 198, 202, 206, 335 Control unit 88 Coordinate list 201 Coordinates 61 Cordtex 222

see also Primacord Core samples 174 Correlated record 50, 58, 186 Correlation 50, 76, 81, 83, 191, 336 Correlation noise 89, 90, 99, 116 Correia tor 38, 49, 50, 82, 83, 149 Coupling 204 Coverage 12

see also CDP coverage Crew morale 146 Crew personnel and damage 210 Critical distance 72, 73, 73 Crooked line stack 326, 342, 345,

346 Cross-correlation 49, 58, 196,337, 339,

352 Cross-feed 89, 90, 155

from airwave 91, 91, 115, 115 from ground-roll 91, 91, 115, 115

Cross-section 10 seismic 23, 63, 157, 173, 316, 349 weathering 169

Cross-talk 148, 149

Index 363

Cultivated land 215, 216, 218, 243, 284

Cultivation 243 Cuttings 175 Cut-off point 103 CVS, see Constant velocity stack

Daily management 70 Daily production 261, 271 Daily production graph 263 Daily production table 262 Daily tests 149, ISO, 150, 151 Damage 33, 206, 208, 243, 284

claims 210 costs 258 explosives 208, 209, 223

Danger zones 204 Dangers of desert work 233 Data acquisition I, 11 Data channels 42

see also Trace Data processing 4, 10, 11, 16, 18, 74

analog 186, 187 basic processes 189-91, 191, 328 CDP stack 191, 195-7 digital 12, 13, 186, 187 evolution of 186-9, 187 extra processes 192, 197,341 field 12, 13, 186, 187 manual 22-5, 61, 186, 187, 190, 195 other processes 192, 197, 341

Data processing centre 16, 62, 65, 71, 186

Data processors 117 Data quality control 72, 75, 103, 188,

190, 193 see also Field parameters 107

Datum surface 63, 157, 158, 196 Dead trace 83, 114, 326 Deconvolution 80, 190, 191, 194, 197 Deephole velocity surveys 173-5, 178,

179, 181, 219 computations 176-80 interpretation of the results 179,

181 walkaway 179

Defective traces 77, 82, 154 dead 83, 114, 326 distribution 83 maximum number 83

noisy 83, 114 reversed 83, 114, 326 weak 114

Delay time 335 Demultiplex 50, 189, 191 Demultiplexed records 193 Depth calculation 173 Depth of hole 174, 301 Depth samples 178 Depth spacing 178 Destruction of ordnance 212 Detail survey 3, 118, 182 Detonating cord 52, 223

see also Primacord Detonation 22, 51

radio-controlled 22 Detonators 142, 151,222

electric 55 position 303

Detonator wiring, leads 160 Deviation of lines 198 Deviation of phase angle 89 Deviation of vibrator sweep 88 Diagnostic processes 195 Diary 256

unusual incidents 256, 257 Differential normal moveout 328 Diffraction 72, 316 Digital computers 186, 187, 188, 189

mainframe 187, 189 micro-computers 187, 189 mini-computers 187, 189 real time 354

Digital recording 16, 48, 97, 186, 188, 326

Digital systems 49 Digital tape 46 Digitization 38, 81 Dimensions of the arrays 294 Dinoseis 57 Direct wave 72 Discontinuity 16 Display mode 96, 97, 102, 104, 108,

112 Distribution, areal 79 Dogbox 31, 31, 32, 226, 351, 355

air conditioning 32 heliportable 32, 35, 36 safety 32-3 vehicular 32, 34

364 Index

Domain: space, time 17 Downhole method 158, 160, 161, 161

see also Uphole Downsweep 60, 285 Drill rig 65, 220, 233 Drilled holes 284, 301, 314 Driller 112, 174, 219, 220, 284 Driller's log 112, 252 Drilling 2, 7, 8, 173, 258

deephole velocity survey 174, 175 exploratory well 9, 10, 70, 71, 186 short-drill 112, 219, 220 shothole 70, 71,219, 220 uphole 70, 71, 219, 220

Driving 233 ice 233 mud 233 sand 233 snow 233

Driving hazards 229, 230, 231 Dynamic corrections 24, 186, 191, 196,

318 Dynamic range 27, 148, 149 Dynamite 52, 115

Earth tamper 57, 351, 352 Earthquakes 89, 93, 96 EDM instruments 199, 238 Elevation 24, 63, 113, 114, 119

maximum difference 119 Emergency supplies 232 Energy source 29, 30, 51, 52, 280,

284 deephole 174 permitting 208, 209 uphole 166 see also Explosives; Source

Energy source validity and timing 142

Equipment 11, 12,31, 145, 149, 199 deficiencies 145

Equipment tests 148, 179 Evenden, B.5. 31, 155 Evolution of seismic recording 16, 18,

19,22-8 Expanded playbacks 301 Explosives 71, 234, 301

brush fire 223, 224 inspector 222 inventory 222

magazine 222 manual, handbook 222 source 16, 52, 78 storage and handling 222 unsafe practice 234

Failed charge 225 Farmers 33, 208, 216, 243 Faults 17, 72, 281, 316 Fibre-optic cable 90 Field crews 187 Field data processing 4, 11, 10-12, 13,

70 see also Data processing; Support

Field geometry 280, 281 group interval, spacing 281 maximum offset 281 number of receiver groups 281 position of shot centre 282 shot to near trace offset 282 spread configuration 282

Field interpretation 103, 117 Field monitors 117 Field parameter testing 194 Field parameter tests 107, 118, 194,

280,345 amplitude equalization 294 interpretation of 194 number of playbacks 194, 297 procedure 285-94 reflections 294

Field parameter tests procedure 285-94

case study 287, 294, 301 comments 286 data processing 286 gain settings 286 instrument settings 286 noise study 286 observer's log 286 paper records 286 site 286 source and receiver arrays 290,

291 Field parameters 73, 75, 75, 81

fixed 75, 75, 76, 76-81 flexible 75, 75, 76, 77, 81-8, 90-5

Field processing system 276 Field survey methods 200 Field test layout 293

Index 365

Field testing 2, 191, 193, 194, 260 ad hoc tests 194, 271, 274 comparisons, see Source and

receiver arrays layout 293 principles and method 270, 271,

292,293 Filter operator 197 Filter parameters 22, 47, 76, 97, 103 Filters 39, 47, 81, 103, 104, 314, 348

instrument tests 149, 149 see also Field data processing; Field

testing; Ground parameters Final reports 268, 269 Firefighting 224 Fire: brush, forest 223, 224 Firing line 223 First aid 233 First break analysis 164 First breaks (arrivals) 72, 73, 108, 114

amplitude of 73 CDP switch position 113 evaluation 102 gain 98 in 3-D 184 refraction statics 335 uses 73

Fixed gain 97, 114, 116 playbacks 99, 100, 275, 276, 277 see also Gain

Fixed-point mode 48 Flagging 128 Flash floods 204 Floating point mode 48 Flow lines 247 Fold of CDP coverage 79, 282 Fold-back spread 293, 294 Footprint 85, 342, 343, 344, 348

crooked line stack 345 3-D 182

Foremen 31, 38, 119, 236 duties 33, 119, 240, 242

Frequency 41, 50, 197,294, 306 Frequency of noise tests 93 Frequency of playback records 94 Frequency of sweep tests 88 Frostbite 233

Gain 22 AGC 22, 23, 97, 316

analog 97 digital 97 fixed 97 PGC 48, 97, 98, 110

Gain control 39, 47, 48, 314 Gain linearity 148, 149 Gain recovery 191 Gain setting 77

attack rate 22, 48 initial 22, 48 overall level 22, 48 rate of change 98

Galvanometers 19,96, 104, 314, 315 Gap in geophone spread 46, 107, 108,

113 fixed field parameters 76, 79 flexible field parameters 77, 85

Gaps in 3-D 191 Gardner's delay time method 163,

335 Geldart, L.P. 15, 335 Generating stations 92, 247 Geodetic parameters 198, 200 Geoflex 55, 222

see also Prima cord Geologic conditions 116 Geologist 175 Geology 7, 7-9 Geometrical effects 79 Geometry of the receiver array 284 Geometry of the source array 284 Geophone array 38, 39, 40, 82, 90,

303, 305, 307, 314 fixed field parameters 76, 79 maximum offset 78 modification 118-20, 121-7, 126, 128

Geophone array interval 77 see also Group spacing

Geophone interval 318 see also Group spacing

Geophone patch 82 Geophone patterns 79

see also Geophone arrays Geophone spacing, in LVL 164 Geophone spread 42, 43

condition 114 Geophone string 41, 82, 82 Geophone traces

number 316 spacing 316

366

Geophones 19, 31, 149, 348 baseplate 39 burial of 242 clamping 160 continuity 242 coupling 120 horizontal 41 impedance 41 leakage 242 moving coil 39 moving magnet 39 resistance 242 resonant frequency 41 response 41 spike 39 string 41, 82, 82 three-component 41

Geophones and cables 154, 226 continuity 154 leakage 154 polarity 154 resistance 154

Geophysical survey 10, 70 acquisition 10, 10-12 evaluation 10, 10-12 gravity lO, 10, 11 interpretation 10, lO-12 magnetic 10, 10, 11 processing 10, lO-12 program 10, 11, 12 seismic 10, 10-14 sequence 10, 11, 12

Geophysicist 12 Geophysics 7, 7-9, 15 Government departments 2lO Governments 212 Graphs 259, 261, 263 Gravity survey 10, 10, 11 Ground parameters 76, 77, 77, 82 Ground position 61 Ground position interval 77

see also Group interval, spacing Ground position number 334 Ground stations 157, 203 Ground-roll 73, 74, 89, 316, 320, 348

cross-feed 91, 91 filter 81 geophone array 79

Group interval, spacing 76, 77, 281, 291, 318

Index

Groups of geophones 19 see also Arrays

Groups of traces 95 Gullies 216, 217, 218

Hagedoorn's plus-minus method 335 Hard hats 233 Hard-wire similarity tests 143, 149,

151-4, 152, 190 Harness, weighted 160 Harvest, allowance for 243 Hazards 204, 229, 230, 231 Heat exhaustion 233 Helicopters 30, 38, 65, 71, 223

cache basket 226 long-line 226 mountains 226 pilot responsibility 226 safety 226, 227

Hermaphroditic cable 41 see also Cables

Hidden layer 18, 163 High resolution surveys 41, 174, 283,

347,349 conventional recording 348 cost 347, 348 drilled holes 348 oil and gas 348 shallow targets 347

Highline pickup 89, 92 Highway 88 High-cut filter lO3, 283 History of seismic exploration 16,

314 Hole collapse 175, 178,219,301 Horizon lO, 17, 19, 61, 72, 173 Horizontal distance 345 Hydrophone 41, 160, 175, 348

cable 160, 163, 167 Hygiene 146, 212, 228

IAGC, see International Association of Geophysical Contractors

Impedance of geophone 41 Inducements 2lO Inertial switch 161 Initial gain settings 87, 110 Initiation time 142 Input panel 38, 45, 82, 82 Input socket 82

Index 367

Instrument tests 148-50, 149, 193 data processing 190, 191 recording instruments 148-50, 150,

151 source 151, 152, 153

Instruments 199 Intercept time 166 Interconnectors 82, 82 International Association of

Geophysical Contractors (IAGC) 228

Interpretation 4, 10, 10, 11, 187 birddog 70 field parameter testing 194 party chief 237 seismologist 61, 315 spurious 316 uphole/LVL 168-9

Interpreter 12, 17, 86, 117, 189 Intersection 201, 267, 326 Interval velocities 178, 179, 181 Inventory of explosives 222 Invoices, approval 94 In-line array 303, 303 Irregular patterns 265, 268

Jug hustlers 31, 119, 236, 240, 241 Jug truck 31, 33, 37, 242 Jungles 214, 223, 226, 233 Junior observer (JO) 31, 33, 38, 119,

236,240

Keys, D.A. 15, 335

Land mines 64, 212, 213 Land survey 30, 61, 70 Landowners 208 Layer thickness 158 Layout crew 31, 118, 236, 240, 242 Leakage 89, 149, 154, 155, 242

air-wave 91, 91 ground-roll 91, 91 signal 90, 91, 91

Lease 7, 7-9 Leave schedule 235 Line access 85, 205, 206 Line access diagrams 205, 206 Line clearance 30, 64, 65, 70, 71 Line intersections 201, 201, 203, 203

diagram 203

Line position 200 Line spacing in 3-D 182 Line summary 266, 268 Linear sweep 285 List of line ties 203 Lithology log 181 Livestock 208 Local inhabitants 204, 205, 210,

221 Loop closure 201

horizontal 201 internal ties 201 maps 201 vertical 201

Low velocity layer (LVL) 29, 57, 63, 163

birddog 70, 71 method 163, 164, 166 results and interpretation 167-9 spread 165 surveys 163-9

Low-cut filter 81, 103, 283 LVL, see Low velocity layer L-spread 294

Magnetic declination 199 Magnetic heads 24, 47 Magnetic recording 16, 23, 315 Magnetic survey 10, 10, 11 Magnetic tape 23, 39, 82, 82, 83,

186 format 50, 51, 76, 81 number 326

Maintenance 145, 146 Mandatory tests 148 Maps 199, 212, 244

minefield 212 Markers 205 Match filter 175, 179 Maximum offset 77, 78, 85, 281, 294 Mean sea level 63 Medical kits 233 Microseisms 315 Migration 23, 192, 197,316 Mine clearance 4, 30, 64, 212, 236,

258 camp 147

Mine clearance log 253 Minefield 213 Mining surveys 158,283,348

368 Index

Mini-SOSIE 57, 116, 142, 349, 350 ambient noise 354 damage 355 golf course 355 heavy traffic 355 instrument 351, 351 master-slave 354 random noise 355

Mirror (galvanometer) 315 Misfire 84, 225 Mix 314 Monitoring 95

equipment 95 real-time 95

Monitoring parameters 77, 88, 96 single trace 96 whole spread 96

Monitoring tests 81 Monthly instrument tests 143 Monthly report 263 Monthly tests 150 Moveout, differential 90 Moveout curve 23 Mud 174, 219, 231 Mueller clips 41 Multiple reflections 316, 318, 335 Multiplex 50 Multiplexer 39, 46, 47, 82 Multi-channel processes 342 Multi-layered medium 72 Murphy's law 234

Near-surface velocity 119 Near-surface weathering conditions

158 Nitroglycerine 222 NMO correction 23, 24, 196,315,339 No loss of production (tests) 279, 280 Noise 74, 79, 89, 243

broadside 286, 288 electrical 89 highline pickup 89 in-line 286, 288, 315 outside, random 79, 89, 89 source-generated 24, 89, 93 transient 87, 89 wind 79, 89

Noise and noise level 75, 77, 89, 99, 108

Noise attenuation 90, 297, 301

Noise reject 39, 49, 77, 93, 108, 117 Noise reject parameters 49, 87 Noise spread 286, 287 Noise strip (test) 77, 92--4, 92, 93 Noise study 286, 288, 289

cross-spread 289 L-spread 287, 294 record 278, 287-91, 297 trace spacing 289 T -X display 289

Noise study and geophone arrays 295,296

Noise study (walkaway test) 286, 288, 289

Noise test 278, 288-91, 297 Noise train 306 Non-linear sweep 285 Normal moveout 315, 318, 339

see also NMO correction

Observer (OB) 32, 163, 166,223 Observer's log 85, 109, 153, 250,

284 field parameter tests 286 label 109 undershooting 86

Obstructions 119, 200, 247, 346 Octal binary 109 Offset 85, 106, 204 Offset split 320 Off-end 320 Oil exploration, sequence 6-10, 7 Operations 13, 29, 30, 243-7

birddog 13, 71, 243 problem 248 suspension of 91

Operators' logs 249-55 Order of lines 94, 243, 245, 245, 246 Ordnance 212 Organization chart 236, 237 Orientation 182 Oscilloscope 88, 95, 96, 142 Overthrust areas 340

Paper monitor 23, 39, 52 Paper playback 52, 77, 96, 97, 188

see also Playback Paper record 19,22, 144 Paper speed 96, 97, 104, 111 Paper timing 111

Parabolic distribution 74 Parameter tests 11, 189 Party chief 4, 187, 236, 237

birddog 71, 71, 150, 271 operations 243 processing centre 187, 188

Party manager 71, 71, 150, 236, 237, 243

Patterns of drilled holes 19 Permanent markers 61, 204, 267,

268 birddog 203 list 204, 204

Permits 199, 210, 218, 221, 245 Permitting 30, 33, 71, 198, 208, 258 Perpendicular offset 83, 114,200 Personnel 31, 71, 226, 235-42,

236 leave rotation 235 replacement 235

Personnel log 255 PGe, see Programmed gain control Phase 81, 89, 143, 152, 194 Phase spectra 276, 278 Photographic development 315 Photographic paper 19, 315 Picking of arrival times 168, 178,

179 Pickup crew 31, 236, 240 Pilot sweep 49, 50, 88, 113, 152 Pilot trace 336 Pipelines 92, 247, 279, 280

minimum distance from 247 Plastic casing 175 Playback 24, 94, 77, 271, 297

attributes 108 camera 82, 82, 83 filter 96, 97, 103 gain mode 96, 97, 108, 110, 111

Playback centre 16, 24, 62, 186, 187, 318

Playback parameters 97, 301 Plotter 101

see also Camera Plus-minus method 335 Point receiver 164, 288 Point source 288, 294 Polarity 149, 154, 155 Police 221 Populated areas 346

Index

Position of shot centre 282 Post-stack processing 341 Poulter shots 19

see also Air-shots Power lines 81, 89, 92, 222, 247 Power spectra 194, 276, 278 Prescribed array 128 Pre-stack processing 341 Price 3, 9 Primacord 55, 222, 284, 301, 303,

airwave 55, 55, 115, 223 arrays 304 comparisons 302 permitting 208, 209 plough 56, 56, 57 splicing 223

Primary reflections 316, 318 Principles and methods of field

testing 270, 271 Priority of lines 243

369

Procedure for field parameter tests 284

Processing centre 30, 50, 184 Production 2, 256, 257, 260

graph 261, 263 irregular patterns 265 line summary 266 lines recorded 264 map 260, 261, 263 rate 78 table 262

Production costs 8 Profile number 334 Profile of static corrections 63, 64 Profiles 10

see also Seismic lines Program 1, 10, 11, 12, 17, 61

changes 189 map 199, 200, 244, 245 order of lines 245-7, 246-7

Programmed gain control 48, 97, 98, 110

see also Gain Protective clothing 233 Pulse test 149, 150 Pumping stations 247 Pumps 92

Quality control 1, 62 observer's 97

370

see also Data quality control Quality control supervisor 1, 70

see also Birddog

Radio signal 151 Radios 31, 33, 149, 222, 232

energy source 142 input panel 45

Random distribution 350, 355 Random sweep 60 Raster block 104 Raw records 186 Raypath 19

diagram 19, 21, 316, 320 distribution 342

Receiver array 24, 299, 300, 348 condition of 73

Receiver groups, number of 281 Receiver parameters 76, 79 Receiver positions 19 Receivers 30, 280, 284

see also Geophones; Hydrophones Reconnaissance survey 3, 195,243,

283,318 bulldozing 214 field parameters 118 program 9

Record 78 composite 78 field 74 file number 101, 108, 108, 109 label 108, 109, 110

Record length 58, 280, 283 fixed field parameters 76, 80 playback 108, 111

Record orientation 107 Recorder 22, 30, 33, 71, 149 Recorder/stacker 161, 166 Recording 16, 30

analog 27 demultiplexed 51 digital 16, 27 multiplexed 51 system 38, 39

Recording cab 31 see also Dogbox

Recording crew 13, 30, 31, 32 repair facilities 31

Recording equipment 145 Recording filters 280, 283

Index

Recording instrument 31, 32, 35, 46, 314

instrument tests 148 mini-SOSIE 351, 354 seismic trace 82, 82

Recording instrument parameters 76, 77, 80, 87, 286

Recording instrument tests 148 cross-talk 148 dynamic range 148 gain linearity 148 mandatory tests 148

Recording production 258 Recording spread 94 Recording truck 31, 82 Recovery shots 85, 86, 184, 192,

326 Reflection 15, 16, 72, 197, 294

coherent 74 continuity of 75 genuine primary 90 method 18, 19 multiple 89, 90, 196, 316, 335 quality 108, 117 Snell's law 16

Reflection point 42, 85 Refracting boundaries 72 Refraction 16, 16, 18, 63

arrivals 72, 78 geophones 164 records 164 total 73

Refraction method 18 Refraction static corrections 335 Refraction statics 64, 163, 169, 192,

196,335 Relative amplitude 98, 153 Repeater boxes 82

see also Boosters Reports 260

final 268, 269 monthly 263 production 260, 261-4, 261 weekly 260

Reproduction quality 108, 112, 113 Reservoirs, oil and gas 6, 9 Residual corrections 196, 197 Residual NMO 196, 197,341 Residual statics 196, 336, 336 Resistance 149, 154, 155, 242

Response 41 see also Array responses

Reversing alarms 233 Roads 246, 247, 346 Roll-along 42

box 45, 320 switch 42

Rotalong 46 see also Roll-along

Royalty agreements 6

Safety 4, 146, 226-8, 230, 231 birddog 71 breach of the code 229 code of practice 228 equipment 229 explosives 223 handbook 228 IAGC 228 meetings 228 unsafe practice 234

Safety audit 228 Safety Officer 229, 236 Sample rate 76, 80, 280, 283, 348 Sampling 47, 160, 163 Sand dunes 119, 215, 216, 223, 232,

284 Sand mats 232 Satellite systems 206, 207 Scouting 243 Sections 4

see also CDr stack SEG, see Society of Exploration

Geophysicists SEG-C 51, 81

see also Magnetic tape, format SEG-Y 51, 81, 107

see also Magnetic tape, format Seismic crew 2, 15,29, 30 Seismic data quality 72, 83

see also Data quality control Seismic data quality control

elements of 75, 75 see also Data quality control

Seismic lines 10, 12, 61, 198, 200, 316

deviation 200 number 334 orientation 200 position 200

Index

re-recording 188 Seismic operations 13, 31, 70, 208 Seismic profile 10, 12, 61

see also Seismic lines Seismic program 11, 17, 61, 189

alterations 189, 195 Seismic record 17

see also Record Seismic spread 19, 20, 26 Seismic survey 10, 158 Seismic trace 82, 82

see also Trace

371

Seismologist 22, 61, 236, 238, 315, 326 deephole velocity surveys 174, 178,

179 field data processing 187, 188 quality control 93 uphole/LVL 163, 166

Seismology IS, 30, 61, 71 Selective playback 279 Senior mechanic 236, 239 Senior observer (OB) 31, 236, 238,

271 Senior surveyor 236, 238 Senior vibrator mechanic 236, 239 Shake-table 15 Shallow section 174 Sherriff, RE. IS, 355 Shift-and-add 352, 353 Shooter 22, 112, 221, 223, 236 Shooter's log 112, 252 Short-drill 112, 219, 220 Shot offset 77, 178 Shot to near trace offset 282 Shotguns 57 Shothole 52, 174, 219 Shotpoint 61, 78 Shotpoint interval 76, 78, 316, 318 Shotpoint location map 61, 201, 202 Shot-generated noise 89, 89 Shot-to-receiver distance 79

see also Gap ... Signal 27, 108

digitized, filtered 38 Signal and noise level 116 Signal-to-noise ratio (SIN) 47, 108,

lIS, 116, 197, 337 Signature of source 175 Sign-bit recording 116, 340, 354 Similarity tests 143, 149, 151-3, 152,

372 Index

153, 190 Single-fold coverage 19,20,21, 186,

316,318 Site 286 Skipped shotpoints 77, 83, 84, 191,

247,326 Sledge hammer 57, 161, 162, 175 Slip-face 119, 216 Snakebites 233 Snell's law 16 Snowmobiles 232 Society of Exploration Geophysicists

(SEG) 51 SOSIE 350

see also Mini-SOSIE Sound wave 30

frequency 306 velocity 306 wavelength 306

Source 16, 30, 51, 71, 149, 151 non-explosive 57 surface 16, 24, 52, 71, 145, 223 see also Vibroseis

Source and receiver arrays 290, 291 comparison arrays 290, 292, 293 explosives 301, 302, 303, 304 fold-back spread 293, 294 geophone arrays 294, 295, 296, 299,

300 various arrays 303, 303, 304 vibrator arrays 294, 298, 299

Source arrays 80 modification of 84 vertically stacked 128 weighting of elements 285

Source array comparison 298, 299, 301

Source parameters 76, 79 Source units, number of 77, 128 Source validity and timing 118 Source-generated noise 93, 278, 283 Spatial filtering 341, 342 Spatial resolution 342 Spatial sampling 316 Spectral analysis 194, 278 Spread configuration 79, 282

asymmetric 79, 282, 334 off-end 79 split 79, 91

Spread geometry 73

Spread of geophones 19 Stack chart 86, 291, 320

data processing 191, 192, 328 seismologist 320, 326, 328 shotpoint between geophones 324,

325, 327, 328 shotpoint on geophones 328, 330,

331 types 324, 325, 326, 327 undershooting 86

Stacked section 70, 189, 190, 195,290 high resolution 347, 349, 349

Stacker 39, 49, 149 correIa tor 49 trace 82, 82 uphole/LVL 161, 166

Stacker settings 76, 81 Stacking 83 Standards of safety 228 Standby 94, 246 Star array 303, 305 Start gain 98

see also Initial gain settings Start of line 332, 333, 334 Static corrections 24, 318, 326

computations 41, 64, 157, 158, 166 data processing 186, 191, 196 first breaks 73 residual 79, 119, 192, 197, 336 uphole break 112

Statics 63, 157 see also Static corrections

Station interval 77 see also Group interval, spacing

Station list 201, 202 Station markers 203 Station numbering 200 Stations (geophone positions) 200 Statistics 258

graphs 259 Steel plate 161 Stone, D.R. 31, 155 Strata 17, 19, 316 Sub-contractors 147 Sub-surface changes 116 Sub-surface coverage 42, 316, 317,

321-3,329 data processing 186 see also CDP

Sub-surface spacing 42

Index 373

Sub-surface structure 1, 12, 173, 186 3-D 17 dip 282 target 282

Sub-weathered layer 164, 196, 335 Sunshots 199 Supervision 70, 71, 72 Support 29, 30, 65, 71 Surface conditions 116, 204 Surface shots 52, 54, 301 Surveys 9, 12, 17

3-D 9, 182 detail 3, 118, 182 geophysical 9, 10, 70 gravity 10, 10, 11 magnetic 10, 10, 11 near-surface 63 reconnaissance 3, 195, 243, 283, 318

Survey equipment 199, 199 Survey parameters 200 Surveyor 4, 61, 62 Surveyor's log 254, 258 Survival 232 Suspension of work 274 Swath 182, 183, 184 Sweep length and type 285 Sweeps 51, 58, 60, 93, 142

birddog 88 correlation 143 deviation 77, 88, 143 direction 60, 80 frequency range 283, 285 length 50, 58, 80, 281, 285 linear spacing 142 listening time 58 number 128, 142 number per VP 281, 285 type 60, 80, 281, 285

Synthetic seismic record 72, 73 Synthetic seismograms 173 Systems 29, 30

essential 30, 31, 31-62 optional 30, 63-9

SIN, see Signal-to-noise ratio

Tail spread 113, 334 Tail-in 113, 245, 332, 333, 332-4 Tail-out 113, 245, 334 Take-out 19, 42, 73, 82, 82, 164 Tap test 46

Target 78, 282 anticline 281 fault 281 pinch-out 281 reef 281

Tax structure 6, 9 Telemetry 27, 38, 42, 82

radio link 45 Telemetry boxes 31, 38, 39, 45, 82, 82 Telford, W.M. 15, 335 Termination of survey 210 Terrain 74, 84, 182, 214 Thin sequence 316 Threshold 88

see also Noise reject Threshold value 49, 87 Thumper 24, 51, 57, 58, 78

deephole velocity surveys 174, 175 uphole/LVL 161, 166

Time contract 2, 146 Time switch 161 Time window 112, 276, 336, 339 Timebreak 22, 51, 87, 108, 112, 315

false 94 Time-depth chart 181 Timing lines 22, 108, 111, 149

compression 111 dilation 111 spacing 111

Tolerance of departure 200 Topographic map 19 Topographical survey 13, 30, 71,

198-207, 199-206 control points 198, 206 deviation of lines 198, 280, geodetic parameters 198, 200 line ties 201, 202, 203, 207 station list 201, 202 survey methods 198, 200

Topography 11, 74 Total charge size 301 Towing 232 Trace 42

elements of 82, 82 / numbers 108, 109, 110, 326

quality 108, 114 reversed 73 selection for playback 77, 95, 97 separation 105, 107 spacing 289

374

Trace selection for playback 77, 95, 97

Traces per record 76, 78 Tractor 223 Traffic 87, 89 Traffic noise 93, 96 Transient noise 87 Transmission 30, 38 Transport 30, 65, 71 Travel path 182 Travel time 158, 243 Traverse 201, 207 True reference 152 Turnkey contract 3, 146, 219 T-X display 289

Uncorrelated record 50 Underground power cables 92 Undershooting 84-7, 191 Unusual incidents 256, 257 Uphole 29, 30, 175, 219

birddog 70, 71 energy source 57 equipment 160-1, 162, 163 method 158-63, 159, 161 results 166-72, 167-9, 258

Uphole break 22, 108, 112, 158, 219, 315

Uphole geophone 315 Uphole method 159, 159 Uphole surveys 29, 30, 158-63, 162,

175 birddog 70, 71

Uphole time 22, 112, 315 Uphole/LVL 335 Uphole/LVL observer's log 251 Uphole/LVL surveys 13, 30, 63,

156-69,258 Upsweep 60, 285

Variable area 97, 102, 104, 186 Variable density 186 Various arrays 303 Vehicles 31, 146, 229, 230, 231 Velocity 19, 24, 63, 294, 306

near-surface 119 Velocity analyses 119, 191, 192, 196,

339 Velocity corrections 196 Velocity filtering 192, 341

Index

Velocity function 24, 318 Velocity in LVL 169 Velocity of transmission 157 Velocity scan 192, 196, 340 Velocity stacks 192, 340 Velocity survey 318, 319 Vertical stack 24, 90, 116, 128 Vertical velocities 178, 181 Vib leader 240 Vibrating point (VP) 285

see also Shotpoint Vibrator operators (Vibop) 236, 240 Vibrator sweep 76, 80, 88, 108, 113,

149 see also Sweeps

Vibrator sweep frequencies 281, 285 Vibrators 58, 65, 88, 145, 229, 284

arrays 59, 308 hydraulic system 60 minimum number of 86 number 77, 86 performance of 189 reliability of 144 shotpoint 78

VIBRA-CHECK 142,143 Vibroseis 24, 57, 58, 83

correia tor 49, 50 first breaks 74 noise reject 87 recording instrument 32

VP, see Vibrating point

Walkaway test 181, 179, 286, 318, 319

War ordnance 64 Waters, K.H. IS, 158 Water-bath 154 Waveforms 23 Wavefront 72, 294 Wavelength 120, 294, 306 Weather 246, 256 Weathered layer 18, 41, 63, 156, 157,

163 Weathering (Wx) 12, 114, 156-8, 157,

169, 173 Weekly reports 260 Weighting 25, 120, 160, 285, 301,

303 Weight-drop 57

see also Thumper

Well 186 exploratory 8, 9 location 12

Well-logging 173 Well-site 9 Whiplash 229 Wiggle trace 97, 102, 104, 186,315 Winch truck 229 Winching 232, 239

Index

Wind 41, 92 Window 87, 88, 111

see also Noise reject; Residual statics; Velocity analyses

Wind-chill factor 228 Wireline reference 152 Wx, see Weathering

Zone of interest 297

375