CAGC Column: Seismic Program Evolution
& Development – High Level Summary
ROD GARLAND
MANAGER OF MEMBER SERVICES,
CANADIAN ASSOCIATION OF GEOPHYSICAL CONTRACTORS
CAGC represents the business interests of the seismic industry
within Canada – www.cagc.ca
The following is anecdotal based on my experiences working for
several Data Acquisition & Oil companies and owner/manager of a
Survey & Auditing company, as a Head Surveyor / Cat Push / Drill
Push / Permit Man / Party Manager / Survey Processor & Auditor for
the period starting in 1975 to present.
Evolution of seismic lines – A Surveyor /Cat Push perspective
Prior to 1975
Line Widths New Cut 25’ (8m), some existing trails were used that tended to bend to
follow the higher solid ground with minimal widening (cutting)
Line Clearing Cats 1950’s & 1960’s (D2, D3) 1970’s (D4, D5, D6,), Chainsaws
Slash Disposal New Cut (slash pile on side of line), Chainsaws cut up debris
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs) some Cats, and tracked
Nodwells & Bombadiers used in wet areas (muskeg lakes, riparian and in
steep terrain & Arctic.
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 5lbs – 100lbs explosive
Shot Hole Depths 30’ (10m) – 300’ (100m)
Safety Formal Safety requirements were virtually nonexistent.
Although some seismic exploration had occurred previously across Canada as early as the 30’s
and 40’s it began in earnest in the 50’s & 60’s mostly in Alberta & BC in search of mainly oil
resources based on preliminary surface studies conducted by Resource Company Geologists &
Geophysicists. As many as 175 crews were active in the late 60’s as discoveries were being
made (e.g. Rainbow Lake).
At that time access & roads were limited in remote northern areas, so many crews were selfcontained
and mostly self-sufficient with all of the necessary services, equipment and vehicles
required to conduct program operations.
These included, bull dozers (D4s, D5s & D6s Cats) used for clearing (sometimes long) access &
the planned seismic lines & towing camps (tent trailers & trailers on sleds / wheels),
accommodation, washroom facilities, power generators, refuse disposal units, propane, cook
shack, mechanics shack, supplies (e.g. food, drilling bits, lubricants, parts) & explosive
magazine.
Personnel included Party Managers , Cat Operators, Drillers, Driller helpers, Surveyors,
Rodmen, Chainers, Recording Crew (Operator & Junior Operator), Line truck drivers, Jug
Hounds, Shooters, Mechanics, Cooks, Camp attendants, Party Managers, Slashers, Permit
land men, Hotshot/Expeditors, Parts supply, Processors, Clerks.
Communication was limited in these remote locations with XJ radio telephones being vital and
usually the only connection with the office in Calgary and the outside world.
Camps moved frequently (sometimes daily) to stay close to the planned program, all phases
(clearing, chaining, surveying, drilling, layout, shooting, pickup) occurred sequentially and in
close proximity to each other. While the camp was being towed by Cats, the lines would be
cleared to a wider width, wide enough (typically 8 metres) to tow strings of trailers and if
wheeled rigs were employed, quite often the clearing removed vegetation for easier access by
those wheeled vehicles.
Seismic exploration was generally all 2D linear and would utilize existing trails and roads if they
were close enough to the program. Supplies (food & mail) were delivered by air drops or float
planes or to an air strip created and plowed on the ice of lakes or the Beaufort Sea.
Surveyors would use alidades & plane tables, transits and theodolites for vertical and horizontal
angular measurements, magnetic compasses, sun / star (e.g. Polaris, the North Star)
observations for azimuth / bearing control and imperial (feet) chains and 15’ stadia rods and
stadia techniques for measuring distances. Astronomical calculations would be based on
printed values supplied in the Solar & Star Almanac for Land Surveyors.
Shot point & receiver point coordinates would be indicated either in Local Co-ordinates usually
referenced south and west of the closest NE corner pin (1st, 2nd & 3rd Township Systems across
the prairies provinces and the Peace River Block in BC) or in Total Co-ordinates relative to a NE
corner pin central to the seismic program.
In BC & the NWT, the NTS (National Topographic System) would be used (BC Grid System or
Yukon & NWT Grid System) as the local co-ordinate reference and later UTM or 3TM.
Expected accuracies were limited based on the methods of the day but generally were 1: 500
with ties to well locations, control monuments, pins, trigs and (highway, & railway) benchmarks
etc. accepted if they tied under 3’ (1m) vertically and better than 30’ x 30’ (10m x 10m)
horizontally (x,y). Internal survey accuracies were much better than that however, loop ties
were usually surprisingly good, considering the difficult terrain & weather conditions and the
production expected to stay ahead of the drills.
Traversing between setup and turn points using lath to mark stations was the preferred survey
method with Azimuth / Bearing ties established as frequently as possible (sun-shots), this was
done to maintain accuracy which would degrade with increasing the number of setups along
the traversed line. Sunshot by Altitude was the preferred Sun observation method recording
simultaneous vertical & horizontal angles from a reference point to the vertical & horizontal
edges of the sun (reduced to an observation to the centre). This prevailed until accurate time
was available from short wave radio checks or time cubes when the Sunshot by hour angle
method was used as an easier observational technique.
Until the mid-70’s calculations were performed using long hand methods aided with slide-rules,
log tables & function tables. These were laborious for example sun-shot calculations would take
approximately 10 minutes to calculate, however 6 were required (3 observations on each
edge/side of the sun) which meant that it would take an hour before an azimuth could be
resolved. With cats and slashers waiting to start cutting based on the results this was very
stressful and the sun wasn’t always visible, especially in northern latitudes.
Data acquisition was analog, and the seismic records were produced and printed in the field,
survey locations of receiver & source points were added to the printed records or supplied on
latitude & departure summary sheets with point elevations and the positions manually inkplotted
on to Mylar maps of the program.
Depending on the expected subsurface condition and depth of hole required, drills could be
conventional drills (sometimes drilling deep holes up to 300’) with large explosive charge sizes
(10-100lbs). These drills, in some areas they would have to drill through gravel, would only be
able to drill 1 to 6 holes in a day and would need a constant water supply whilst drilling which
would require a water truck that would ferry water.
Other drills including Augers, Hammer & Top-drives also needed a water support, The drills
were mostly full size wheeled units and tracked Nodwells or Bombadiers with water trucks also
on tracks that would fill tanks from local sources, sloughs, creeks etc. Later, other drills were
side-winders that could swing the drilling mast 90 degrees into the ditch usually for road
allowance drilling.
Although source & receiver intervals would vary, the source points would typically be at intervals
of 1,320’ (1/4 mile), with geophones at intervals of 220’. Later the source interval tightened up
and became 660’ or 880’, and the geophone interval became 110’. The tighter intervals for the
source and geophones provided better subsurface coverage of the shallower reflectors. Most
work was hourly and program maps would be supplied from the Client for the entire season.
1975 – 1980
Change
require cutting crew (cats) return to widen lines.
Line Clearing Cats (D6, Wide pads and D7), Chainsaws
Slash Disposal New Cut (slash pile on side of line, alternating with barrier breaks in the
pile for fire wick mitigation, wildlife access and for vehicle turnarounds).
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs) Some Cats, and tracked
Nodwells & Bombadiers used in wet areas (muskeg lakes, riparian and in
steep terrain.
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 5lbs – 20lbs explosive
Shot Hole Depths 15’ (5m) – 150’ (50m)
Safety Formal Safety requirements virtually non-existent although some
companies had begun safety programs
From 1975 when I surveyed and pushed cats in the Canadian Arctic, Peace River Block,
Dawson Creek, Fort St John, Prophet River, Chetwynd, Fort Nelson and surrounding area up to
the NWT border and across Alberta & Saskatchewan, contact with all government agencies
was always necessary prior to the program start,.
In BC prior contact with government agencies was at Charlie Lake & Fort St John to review and
discuss approval conditions and obtain sign-off from all of the various resource departments. In
both BC & Alberta agencies which included forestry, fish & wildlife, municipalities, highways,
agriculture, trappers, oil & gas companies, First Nation bands, pipeline companies, timber
harvesting as well as stakeholders and private land owners were contacted.
When lines were cut on crown land, timber damages would be assessed based on the series of
forest cover maps, which took into account the timber density types, length & width of lines.
Compensation would be collected by the crown based on the “timber damages assessed”. As
time went on there was an incentive to minimize line widths to reduce this expense.
The Cat Push, the supervisor of the Cat crew, tended to be an experienced surveyor. The Cat
Push would direct all cutting of bush for access and seismic lines by “striking off” from a known
point on the planned program line using lath / sticks marked with high visible flagging. Often a
survey control traverse or fly line would be necessary to establish the coordinates and
elevations from existing pins, monuments and control benchmarks.
The line direction or bearing of the line required would be established by using sun / star
observations or traversed from an existing traverse where the bearing was already known. Cats
would work in pairs, one initially producing line, the second clearing and widening the line with a
second pass and piling debris to one side of the line in what was referred to as a ‘slash pile’.
The lead cat operator would continue to place liners for a back sight, keeping the line as straight
as possible. Lights would sometimes be used in place of liners to keep lines straight,
sometimes at night. Periodically or when the cat-skinner would encounter an obstruction, such
as a stream, side hill, ravine, pipeline and roads, he would get support from the chainsaw teams
(slashers) to create a detour, and the cats would then re-trace their tracks, cleaning up the
cleared line until it was suitable for passage by pick-ups, drills, recording dog and line trucks.
The slashers would support the line clearing; cut for cable drag-out & line of sight; clean the line
and ‘slash pile’; cut logs for fill at streams; make temporary bridges; do beetle control; and assist
the Cat Push. For remote programs, slashers were hired locally from the indigenous (First
Nation) groups and quite often they would provide services monitoring for wildlife such as bears,
wolves, cougar etc.
Geophysical Companies included, Western, Northern, GSI, Teledyne Exploration, Grant, Petty-
Ray, Seiscom-Delta, Sonics, Kenting, Capilano, Absolute, Veritas, CGG, Lead, Norcana, Sefel,
JRS, Pacer, United, Pioneer, Gale, Digiseis, Arcis, Enertec, Trace, Norex and many more.
Oil company programs on which I worked included, Imperial, Mobil, Husky, Chevron, Gulf, Shell,
BP, Amoco, Dome, Hudson Bay, North Canadian, Pan Canadian, Canadian Superior, Saskoil,
Norcen, Renaissance and many more.
Most exploration at the time was either large regional exploration projects. An example of this is
Chevron acquired seismic on the roads and road allowances in Alberta from the Saskatchewan
border to as far West as they could go, The lines were spaced approximately about 12 miles
apart and were acquired for the search of Pinnacles and Anomalies, and were tied to existing
Wells (known data) when possible.
There was very little in the way of a defined formal safety program, although everyone was
aware of the hazards and associated risk with seismic work. It was very much a team effort to
keep ourselves safe and we would inform our peers on what was going on and where everyone
was at all of the time. We looked after each other and made sure that help was on hand should
anyone break down or get stuck.
There were no specific requirements for safety vests, hard hats, boots or any other PPE;
however everyone was acutely aware of weather conditions, particularly in the Winter. Spare
clothing was a must- have and countless times I was thankful for being prepared after being left
out overnight because the helicopter couldn’t fly on a heli assist job or my nodwell or truck
became stuck in the muskeg.
The hours would be long. We would have to use all of the available daylight time for field work
to maintain the expected production and travel to and from the field was always in the dark.
However calculating, computing, plotting and reducing survey and chaining notes would
consume several hours every night. These tasks could not be ignored or put off for any reason.
Most crews would work a 20 days on and 10 days off routine working up to 18 hours a day.
With myself being from England and with no permanent address in Canada I was able to work
continuously through the Winter busy season which was good for my bank account and my
family back in England.
Seismic life could be considered very disruptive for traditional family life and was known for its
propensity for broken marriages and relationships. The camaraderie on the crew however was
like in no other industry with which I’ve been involved, and friendships formed on the seismic
crew have endured to this day.
1980 – 1985
Change
crew (cats) return to widen lines.
Line Clearing Cats (D6, D7, D8), Chainsaws, 4x4 Tractors snow plowing
Slash Disposal New Cut (slash pile on side of line, alternating with breaks in pile for fire
wick mitigation and for vehicle turnarounds).
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs).
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 2kg – 12Kg explosive
Vibrators (large Vibes were +/- 50,000lbs) up to 4 in Tandem
Shot Hole Depths 15’ (5m) – 150’ (50m), some holes were 3 or 5 hole patterns
Safety Company Safety Programs and training implemented using PITS
In about 1979, although D6 (wide-pad) Cats were mostly used for seismic, bigger Cats D7s and
D8s started to be used with more power and functionality, (e.g. automatic blade control,
mushroom shoes)
Also electronic distance measuring devices (EDM) and more precise theodolites with better
optical magnification became available, although expensive, which greatly improved survey
accuracies and production. At this time basic calculators were starting to be used and the
metric system started to be more widely accepted replacing imperial distance measurements
and parameters.
1985 – 1990
Change
Line Widths Cat cut (8m) – if lines were too narrow, conservation officers would
require cutting crew (cats) return to widen lines.
Mulchers (4- 5.5m) – meandering avoidance (LIS) with a straight survey
sight line (0.5m)
Line Clearing Cats (D6, D7, D8), Chainsaws, Hydro-Axe & Mulchers, 4x4 Tractors snow plowing
Slash Disposal New Cut (slash pile on side of line, alternating with breaks in pile for fire
wick mitigation and for vehicle turnarounds and removal of wildlife
barriers). Mulched line removed need for slash pile created wood chip
base
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs).
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 2kg – 12Kg explosive,
Vibrators up to 4 in Tandem
Shot Hole Depths 15’ (5m) – 150’ (50m) some holes were 3 or 5 hole patterns
Safety Safety training and PITS certificates required for First Aid, TDG, WHIMIS, H2S, Blasting & Chainsaw Falling
This period was a period of momentous change because the Regulatory Imperative and the
mounting pressure on the Oil & Gas industry to reduce its environmental footprint and improve
safety performance increased exponentially. The seismic industry reacted by using and
developing emerging technologies not only with survey technology, which somehow changed its
name to geomatics, and by building or acquiring new low impact, low ground pressure
equipment (mulchers, drills, mini-vibes) and developing new methodologies using GPS, Inertial
& Helicopters.
Safety training and certification became a requirement in part as an outcome from a report in
1987 from UPITFOS, (the Upstream Petroleum Industry Task Force on Safety) that produced
42 recommendations to respond to several fatalities and injuries in the Oil patch in 1986. PITS
(the Petroleum Industry Training Service) became widely used as safety & training service
provider for the industry
1990 – 1995
Change
Source Lines Full Size Vibrators (5.5m), Mini Vibrators (4.5m)
Slash Disposal Little to no slash with mulched lines
Ground Disturbance Little to none, lines recovered within a few growing seasons
Energy Source 2kg – 12Kg explosive,
Vibrators and Mini Vibrators up to 4 in Tandem
Shot Hole Depths 5m – 15m some holes were 3 or 5 hole patterns
Safety Safety training and PITS certificates required for First Aid, TDG, WHIMIS, H2S, Blasting & Chainsaw Falling
Although Cats were still used for snow plowing, towing and on some 2D lines or on Vibrator 3D
source lines, the Mulchers became increasingly the required method for line construction. GPS
crews would produce detailed mapping of 3D programs showing all the culture and hazards and
layout the shot point and receiver locations. Co-ordinators, mappers and data managers played
a more prominent role in the layout and surveying of the program, virtually eliminating chaining
and optical survey crews.
The GPS crew also replaced the need for Cat Pushes and lines could now meander through
bush using the least line of resistance achieved with on-board navigation systems with real time
kinematic (RTK) corrections broadcast from a base control station.
1995 – 2005
Change
Line Widths 3Ds Source lines (3m), Receiver lines (2m)
Source Lines Full Size Vibrators (5.5m), Mini Vibrators (4.5m)
Line Clearing Mulchers, Chainsaws
Slash Disposal Little to no slash with mulched lines
Ground Disturbance Little to none, lines recovered within a few growing seasons
Energy Source 1kg – 12Kg explosive,
Vibrators and Mini Vibrators up to 4 in Tandem
Shot Hole Depths 5m – 15m some holes were 3 or 5 hole patterns
Safety Safety training required from Enform First Aid, TDG, WHIMIS, H2S, Blasting, Chainsaw Falling and additional Industry Recommended Practices
Lines continued to get narrower with less footprint and with the availability of small mulchers &
drills and Integrated GPS /Inertial advances under canopy work was possible without a need for
a survey line of sight.
Enform was created in 2005 with the merger of Petroleum Industry Training Service (PITS) &
Canadian Petroleum Safety Council (CPSC). The certificate of recognition (COR) became
necessary to qualify for work opportunities with Clients.
Large Programs (3D/4D) continued to become more prevalent, speculative seismic jobs
increased and seismic was used for monitoring SAGD and cap rock integrity evaluation.
2005 – 2020
Change
Line Clearing Mulchers, Chainsaws also Zero
Slash Disposal Little to no slash with mulched lines
Ground Disturbance Little to none, lines recovered within a few growing seasons
Energy Source 1/2kg – 2Kg explosive,
Vibrators and Mini Vibrators up to 4 in Tandem plus single sweep
Shot Hole Depths 5m –15m some holes were 3 or 5 hole patterns
Safety Safety training required from Enform now Energy Safety Canada, First Aid, TDG, WHIMIS, H2S, Blasting, Chainsaw Falling and additional Industry Recommended Practices
Seismic continues to evolve with newer, better equipment, smaller charge sizes required and
more sensitive geophones and nodal systems available. Data is significantly better than that acquired back in the 1960’s & 70’s. An analogy would be that of a high-definition colour TV
monitor compared to an old black & white TV screen.
Higher density of source lines and receiver lines also increases the trace density and the fold of
the stacked data which increases the signal to noise ratio giving the geophysical interpreters
cleaner data to work with to illuminate subtle amplitude variations and anomalies which may
represent reservoirs.
It also allows for better resolution of the shallower seismic events which means the seismic
could possibly be used to identify possible aquifers to obtain water for fracking or to understand
geohazards in the placement of the wells.
Stake-less surveys, cable-less autonomous recording systems, sophisticated in-cab navigation
systems with alerts and alarms when encroaching on hazards and exclusion zones have
become commonplace. Single-sweep vibrators working concurrently on lines have in some
cases tripled or quadrupled the production. Helicopters are used to move equipment to where it
is needed and UTVs and snow machines guided by cell phone navigation apps have eliminated
the need for multiple vehicle access on programs.
Regulatory & environmental pressures on the seismic industry to further reduce impacts persist,
(e.g. SARA species at risk, Caribou, Methane emissions, CO2, etc.) even though the industry is
already highly regulated and has spent millions of dollars to adapt to lower its footprint over the
past 25 years. I do not recall other industries such as farming amending their practices to the
same extent & relative cost.
Seismic and Oil & Gas exploration was largely responsible for the opening up of the North, and
the remote communities have greatly benefitted from the resulting development, access, jobs
and wealth created.
In 2016 Energy Safety Canada was formed with the merger of EnForm & OSSA (Oil Sands
Safety Association). The safety performance of the Oil & Gas industry is now second to none
with many oil and gas companies tying their yearly bonuses to the Health, Safety Environment
record of the company including the work done by contractors.
& Development – High Level Summary
ROD GARLAND
MANAGER OF MEMBER SERVICES,
CANADIAN ASSOCIATION OF GEOPHYSICAL CONTRACTORS
CAGC represents the business interests of the seismic industry
within Canada – www.cagc.ca
The following is anecdotal based on my experiences working for
several Data Acquisition & Oil companies and owner/manager of a
Survey & Auditing company, as a Head Surveyor / Cat Push / Drill
Push / Permit Man / Party Manager / Survey Processor & Auditor for
the period starting in 1975 to present.
Evolution of seismic lines – A Surveyor /Cat Push perspective
Prior to 1975
Line Widths New Cut 25’ (8m), some existing trails were used that tended to bend to
follow the higher solid ground with minimal widening (cutting)
Line Clearing Cats 1950’s & 1960’s (D2, D3) 1970’s (D4, D5, D6,), Chainsaws
Slash Disposal New Cut (slash pile on side of line), Chainsaws cut up debris
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs) some Cats, and tracked
Nodwells & Bombadiers used in wet areas (muskeg lakes, riparian and in
steep terrain & Arctic.
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 5lbs – 100lbs explosive
Shot Hole Depths 30’ (10m) – 300’ (100m)
Safety Formal Safety requirements were virtually nonexistent.
Although some seismic exploration had occurred previously across Canada as early as the 30’s
and 40’s it began in earnest in the 50’s & 60’s mostly in Alberta & BC in search of mainly oil
resources based on preliminary surface studies conducted by Resource Company Geologists &
Geophysicists. As many as 175 crews were active in the late 60’s as discoveries were being
made (e.g. Rainbow Lake).
At that time access & roads were limited in remote northern areas, so many crews were selfcontained
and mostly self-sufficient with all of the necessary services, equipment and vehicles
required to conduct program operations.
These included, bull dozers (D4s, D5s & D6s Cats) used for clearing (sometimes long) access &
the planned seismic lines & towing camps (tent trailers & trailers on sleds / wheels),
accommodation, washroom facilities, power generators, refuse disposal units, propane, cook
shack, mechanics shack, supplies (e.g. food, drilling bits, lubricants, parts) & explosive
magazine.
Personnel included Party Managers , Cat Operators, Drillers, Driller helpers, Surveyors,
Rodmen, Chainers, Recording Crew (Operator & Junior Operator), Line truck drivers, Jug
Hounds, Shooters, Mechanics, Cooks, Camp attendants, Party Managers, Slashers, Permit
land men, Hotshot/Expeditors, Parts supply, Processors, Clerks.
Communication was limited in these remote locations with XJ radio telephones being vital and
usually the only connection with the office in Calgary and the outside world.
Camps moved frequently (sometimes daily) to stay close to the planned program, all phases
(clearing, chaining, surveying, drilling, layout, shooting, pickup) occurred sequentially and in
close proximity to each other. While the camp was being towed by Cats, the lines would be
cleared to a wider width, wide enough (typically 8 metres) to tow strings of trailers and if
wheeled rigs were employed, quite often the clearing removed vegetation for easier access by
those wheeled vehicles.
Seismic exploration was generally all 2D linear and would utilize existing trails and roads if they
were close enough to the program. Supplies (food & mail) were delivered by air drops or float
planes or to an air strip created and plowed on the ice of lakes or the Beaufort Sea.
Surveyors would use alidades & plane tables, transits and theodolites for vertical and horizontal
angular measurements, magnetic compasses, sun / star (e.g. Polaris, the North Star)
observations for azimuth / bearing control and imperial (feet) chains and 15’ stadia rods and
stadia techniques for measuring distances. Astronomical calculations would be based on
printed values supplied in the Solar & Star Almanac for Land Surveyors.
Shot point & receiver point coordinates would be indicated either in Local Co-ordinates usually
referenced south and west of the closest NE corner pin (1st, 2nd & 3rd Township Systems across
the prairies provinces and the Peace River Block in BC) or in Total Co-ordinates relative to a NE
corner pin central to the seismic program.
In BC & the NWT, the NTS (National Topographic System) would be used (BC Grid System or
Yukon & NWT Grid System) as the local co-ordinate reference and later UTM or 3TM.
Expected accuracies were limited based on the methods of the day but generally were 1: 500
with ties to well locations, control monuments, pins, trigs and (highway, & railway) benchmarks
etc. accepted if they tied under 3’ (1m) vertically and better than 30’ x 30’ (10m x 10m)
horizontally (x,y). Internal survey accuracies were much better than that however, loop ties
were usually surprisingly good, considering the difficult terrain & weather conditions and the
production expected to stay ahead of the drills.
Traversing between setup and turn points using lath to mark stations was the preferred survey
method with Azimuth / Bearing ties established as frequently as possible (sun-shots), this was
done to maintain accuracy which would degrade with increasing the number of setups along
the traversed line. Sunshot by Altitude was the preferred Sun observation method recording
simultaneous vertical & horizontal angles from a reference point to the vertical & horizontal
edges of the sun (reduced to an observation to the centre). This prevailed until accurate time
was available from short wave radio checks or time cubes when the Sunshot by hour angle
method was used as an easier observational technique.
Until the mid-70’s calculations were performed using long hand methods aided with slide-rules,
log tables & function tables. These were laborious for example sun-shot calculations would take
approximately 10 minutes to calculate, however 6 were required (3 observations on each
edge/side of the sun) which meant that it would take an hour before an azimuth could be
resolved. With cats and slashers waiting to start cutting based on the results this was very
stressful and the sun wasn’t always visible, especially in northern latitudes.
Data acquisition was analog, and the seismic records were produced and printed in the field,
survey locations of receiver & source points were added to the printed records or supplied on
latitude & departure summary sheets with point elevations and the positions manually inkplotted
on to Mylar maps of the program.
Depending on the expected subsurface condition and depth of hole required, drills could be
conventional drills (sometimes drilling deep holes up to 300’) with large explosive charge sizes
(10-100lbs). These drills, in some areas they would have to drill through gravel, would only be
able to drill 1 to 6 holes in a day and would need a constant water supply whilst drilling which
would require a water truck that would ferry water.
Other drills including Augers, Hammer & Top-drives also needed a water support, The drills
were mostly full size wheeled units and tracked Nodwells or Bombadiers with water trucks also
on tracks that would fill tanks from local sources, sloughs, creeks etc. Later, other drills were
side-winders that could swing the drilling mast 90 degrees into the ditch usually for road
allowance drilling.
Although source & receiver intervals would vary, the source points would typically be at intervals
of 1,320’ (1/4 mile), with geophones at intervals of 220’. Later the source interval tightened up
and became 660’ or 880’, and the geophone interval became 110’. The tighter intervals for the
source and geophones provided better subsurface coverage of the shallower reflectors. Most
work was hourly and program maps would be supplied from the Client for the entire season.
1975 – 1980
Change
- Tracked (Nodwells & Bombadiers) & Wheeled Buggies (Rolligons) used for Arctic exploration & Summer programs in wet areas and steep terrain.
- Specialized service companies established in drilling, surveying, front-end that were previously divisions of exploration or Oil companies (e.g. Chevron)
- Independent Survey Data and Data processing companies started (digitization)
- Turnkey jobs (charged by the mile/km) started
- CAGC Seismic Safety standards and Best Practices were introduced 1977
require cutting crew (cats) return to widen lines.
Line Clearing Cats (D6, Wide pads and D7), Chainsaws
Slash Disposal New Cut (slash pile on side of line, alternating with barrier breaks in the
pile for fire wick mitigation, wildlife access and for vehicle turnarounds).
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs) Some Cats, and tracked
Nodwells & Bombadiers used in wet areas (muskeg lakes, riparian and in
steep terrain.
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 5lbs – 20lbs explosive
Shot Hole Depths 15’ (5m) – 150’ (50m)
Safety Formal Safety requirements virtually non-existent although some
companies had begun safety programs
From 1975 when I surveyed and pushed cats in the Canadian Arctic, Peace River Block,
Dawson Creek, Fort St John, Prophet River, Chetwynd, Fort Nelson and surrounding area up to
the NWT border and across Alberta & Saskatchewan, contact with all government agencies
was always necessary prior to the program start,.
In BC prior contact with government agencies was at Charlie Lake & Fort St John to review and
discuss approval conditions and obtain sign-off from all of the various resource departments. In
both BC & Alberta agencies which included forestry, fish & wildlife, municipalities, highways,
agriculture, trappers, oil & gas companies, First Nation bands, pipeline companies, timber
harvesting as well as stakeholders and private land owners were contacted.
When lines were cut on crown land, timber damages would be assessed based on the series of
forest cover maps, which took into account the timber density types, length & width of lines.
Compensation would be collected by the crown based on the “timber damages assessed”. As
time went on there was an incentive to minimize line widths to reduce this expense.
The Cat Push, the supervisor of the Cat crew, tended to be an experienced surveyor. The Cat
Push would direct all cutting of bush for access and seismic lines by “striking off” from a known
point on the planned program line using lath / sticks marked with high visible flagging. Often a
survey control traverse or fly line would be necessary to establish the coordinates and
elevations from existing pins, monuments and control benchmarks.
The line direction or bearing of the line required would be established by using sun / star
observations or traversed from an existing traverse where the bearing was already known. Cats
would work in pairs, one initially producing line, the second clearing and widening the line with a
second pass and piling debris to one side of the line in what was referred to as a ‘slash pile’.
The lead cat operator would continue to place liners for a back sight, keeping the line as straight
as possible. Lights would sometimes be used in place of liners to keep lines straight,
sometimes at night. Periodically or when the cat-skinner would encounter an obstruction, such
as a stream, side hill, ravine, pipeline and roads, he would get support from the chainsaw teams
(slashers) to create a detour, and the cats would then re-trace their tracks, cleaning up the
cleared line until it was suitable for passage by pick-ups, drills, recording dog and line trucks.
The slashers would support the line clearing; cut for cable drag-out & line of sight; clean the line
and ‘slash pile’; cut logs for fill at streams; make temporary bridges; do beetle control; and assist
the Cat Push. For remote programs, slashers were hired locally from the indigenous (First
Nation) groups and quite often they would provide services monitoring for wildlife such as bears,
wolves, cougar etc.
Geophysical Companies included, Western, Northern, GSI, Teledyne Exploration, Grant, Petty-
Ray, Seiscom-Delta, Sonics, Kenting, Capilano, Absolute, Veritas, CGG, Lead, Norcana, Sefel,
JRS, Pacer, United, Pioneer, Gale, Digiseis, Arcis, Enertec, Trace, Norex and many more.
Oil company programs on which I worked included, Imperial, Mobil, Husky, Chevron, Gulf, Shell,
BP, Amoco, Dome, Hudson Bay, North Canadian, Pan Canadian, Canadian Superior, Saskoil,
Norcen, Renaissance and many more.
Most exploration at the time was either large regional exploration projects. An example of this is
Chevron acquired seismic on the roads and road allowances in Alberta from the Saskatchewan
border to as far West as they could go, The lines were spaced approximately about 12 miles
apart and were acquired for the search of Pinnacles and Anomalies, and were tied to existing
Wells (known data) when possible.
There was very little in the way of a defined formal safety program, although everyone was
aware of the hazards and associated risk with seismic work. It was very much a team effort to
keep ourselves safe and we would inform our peers on what was going on and where everyone
was at all of the time. We looked after each other and made sure that help was on hand should
anyone break down or get stuck.
There were no specific requirements for safety vests, hard hats, boots or any other PPE;
however everyone was acutely aware of weather conditions, particularly in the Winter. Spare
clothing was a must- have and countless times I was thankful for being prepared after being left
out overnight because the helicopter couldn’t fly on a heli assist job or my nodwell or truck
became stuck in the muskeg.
The hours would be long. We would have to use all of the available daylight time for field work
to maintain the expected production and travel to and from the field was always in the dark.
However calculating, computing, plotting and reducing survey and chaining notes would
consume several hours every night. These tasks could not be ignored or put off for any reason.
Most crews would work a 20 days on and 10 days off routine working up to 18 hours a day.
With myself being from England and with no permanent address in Canada I was able to work
continuously through the Winter busy season which was good for my bank account and my
family back in England.
Seismic life could be considered very disruptive for traditional family life and was known for its
propensity for broken marriages and relationships. The camaraderie on the crew however was
like in no other industry with which I’ve been involved, and friendships formed on the seismic
crew have endured to this day.
1980 – 1985
Change
- Vibrators (up to 50,000lbs) started to be used more widely as a source method (up to 4in tandem)
- Programmable calculators (Texas Instrument / Hewlett Packard) with data loggersbecame available.
- Computers & plotters used. Data required digitally on tape
- EDM (electronic distance measurement) became more common replacing Stadia
- Metric system implemented
- Pressure mounted to reduce environmental footprint (Caribou & Cumulative impacts) that increased over time.
- Seismic Safety training & certification became a required crew component (e.g. best practices from CAGC that started in 1977)
crew (cats) return to widen lines.
Line Clearing Cats (D6, D7, D8), Chainsaws, 4x4 Tractors snow plowing
Slash Disposal New Cut (slash pile on side of line, alternating with breaks in pile for fire
wick mitigation and for vehicle turnarounds).
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs).
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 2kg – 12Kg explosive
Vibrators (large Vibes were +/- 50,000lbs) up to 4 in Tandem
Shot Hole Depths 15’ (5m) – 150’ (50m), some holes were 3 or 5 hole patterns
Safety Company Safety Programs and training implemented using PITS
In about 1979, although D6 (wide-pad) Cats were mostly used for seismic, bigger Cats D7s and
D8s started to be used with more power and functionality, (e.g. automatic blade control,
mushroom shoes)
Also electronic distance measuring devices (EDM) and more precise theodolites with better
optical magnification became available, although expensive, which greatly improved survey
accuracies and production. At this time basic calculators were starting to be used and the
metric system started to be more widely accepted replacing imperial distance measurements
and parameters.
1985 – 1990
Change
- Low Ground Pressure - Mulchers / Hydro-Axes started to be used to replace Cats (Mulchers were unreliable and prone to breakdown)
- Total Stations (combined angular & distance measurements) & data loggers for digital collection
- 3Ds (line intervals average 400m), and Swath programs (mega-bins) became more common
- Early GPS, still expensive, coverage weak
- Line of sight mitigation introduced along line and at roads / pipelines (moose blinds, doglegs)
- More Spec Companies establish to shoot programs
- 3rd Party Field Management companies programs formed
Line Widths Cat cut (8m) – if lines were too narrow, conservation officers would
require cutting crew (cats) return to widen lines.
Mulchers (4- 5.5m) – meandering avoidance (LIS) with a straight survey
sight line (0.5m)
Line Clearing Cats (D6, D7, D8), Chainsaws, Hydro-Axe & Mulchers, 4x4 Tractors snow plowing
Slash Disposal New Cut (slash pile on side of line, alternating with breaks in pile for fire
wick mitigation and for vehicle turnarounds and removal of wildlife
barriers). Mulched line removed need for slash pile created wood chip
base
Ground Disturbance Non-Frozen (Summer – Fall) high ground skinned for wheeled vehicles
with detours around wet areas (drag-outs).
Frozen (Winter) straight lines with compacted snow / ice
Energy Source 2kg – 12Kg explosive,
Vibrators up to 4 in Tandem
Shot Hole Depths 15’ (5m) – 150’ (50m) some holes were 3 or 5 hole patterns
Safety Safety training and PITS certificates required for First Aid, TDG, WHIMIS, H2S, Blasting & Chainsaw Falling
This period was a period of momentous change because the Regulatory Imperative and the
mounting pressure on the Oil & Gas industry to reduce its environmental footprint and improve
safety performance increased exponentially. The seismic industry reacted by using and
developing emerging technologies not only with survey technology, which somehow changed its
name to geomatics, and by building or acquiring new low impact, low ground pressure
equipment (mulchers, drills, mini-vibes) and developing new methodologies using GPS, Inertial
& Helicopters.
Safety training and certification became a requirement in part as an outcome from a report in
1987 from UPITFOS, (the Upstream Petroleum Industry Task Force on Safety) that produced
42 recommendations to respond to several fatalities and injuries in the Oil patch in 1986. PITS
(the Petroleum Industry Training Service) became widely used as safety & training service
provider for the industry
1990 – 1995
Change
- 3D/4D programs become more prevalent for Oil Sands, SAGD,
- Mulching became the preferred line clearing method
- LIS (meandering avoidance) required for source lines, minimal straight line width on receiver lines
- LIS Drills designed & constructed to fit on reduced width lines
- GPS satellite coverage improved, Russian Glonass system also became available
- GPS replaced conventional survey crews eliminating chaining crews, Real-Time
- Kinematic (RTK) with corrections transmitted to rovers from a known base station control point.
- Plotting of production & hazard maps were done by GPS mappers at camp or motel
- Helicopters utilized to move equipment around programs (bag drop systems, Kodiak Dynanav)
- Use of GPS & Helicopters made narrower, meandering LIS a more cost effective solution saving timber damage penalties or timber salvage costs.
Source Lines Full Size Vibrators (5.5m), Mini Vibrators (4.5m)
Slash Disposal Little to no slash with mulched lines
Ground Disturbance Little to none, lines recovered within a few growing seasons
Energy Source 2kg – 12Kg explosive,
Vibrators and Mini Vibrators up to 4 in Tandem
Shot Hole Depths 5m – 15m some holes were 3 or 5 hole patterns
Safety Safety training and PITS certificates required for First Aid, TDG, WHIMIS, H2S, Blasting & Chainsaw Falling
Although Cats were still used for snow plowing, towing and on some 2D lines or on Vibrator 3D
source lines, the Mulchers became increasingly the required method for line construction. GPS
crews would produce detailed mapping of 3D programs showing all the culture and hazards and
layout the shot point and receiver locations. Co-ordinators, mappers and data managers played
a more prominent role in the layout and surveying of the program, virtually eliminating chaining
and optical survey crews.
The GPS crew also replaced the need for Cat Pushes and lines could now meander through
bush using the least line of resistance achieved with on-board navigation systems with real time
kinematic (RTK) corrections broadcast from a base control station.
1995 – 2005
Change
- Smaller / Narrower Mulchers developed (Hurricanes 2,75, Twister 1.75)
- Smaller LIS Drills designed & constructed to fit on reduced width lines
- GPS / Glonass satellite coverage increased and continued to improve, Inertial Systems were integrated with GPS systems
- Under Canopy GPS system in forested areas
- Navigation systems developed for vehicles
- LIDAR & Satellite Mapping Data used for better pre-planning and layout
- Electronic detonators – for minimizing & eliminating misfires
- Holding a COR (certificate of recognition) becomes necessary to get work
Line Widths 3Ds Source lines (3m), Receiver lines (2m)
Source Lines Full Size Vibrators (5.5m), Mini Vibrators (4.5m)
Line Clearing Mulchers, Chainsaws
Slash Disposal Little to no slash with mulched lines
Ground Disturbance Little to none, lines recovered within a few growing seasons
Energy Source 1kg – 12Kg explosive,
Vibrators and Mini Vibrators up to 4 in Tandem
Shot Hole Depths 5m – 15m some holes were 3 or 5 hole patterns
Safety Safety training required from Enform First Aid, TDG, WHIMIS, H2S, Blasting, Chainsaw Falling and additional Industry Recommended Practices
Lines continued to get narrower with less footprint and with the availability of small mulchers &
drills and Integrated GPS /Inertial advances under canopy work was possible without a need for
a survey line of sight.
Enform was created in 2005 with the merger of Petroleum Industry Training Service (PITS) &
Canadian Petroleum Safety Council (CPSC). The certificate of recognition (COR) became
necessary to qualify for work opportunities with Clients.
Large Programs (3D/4D) continued to become more prevalent, speculative seismic jobs
increased and seismic was used for monitoring SAGD and cap rock integrity evaluation.
2005 – 2020
Change
- 3D & 4D tighter spacing and denser programs
- In 2018, Zero cutting acquisition method used
- Cable-less systems, Autonomous recording boxes
- Stake-less surveys with Navigation system in vehicles (e.g. vibes)
- Single vibes working on different lines concurrently (single sweep)
- High definition, High density programs with line spacing at 10m (shallow) to 60m (deeper)
- Crew counts have diminished to unprecedented levels (3 Data Acquisition companies in 2020 from 15 in 2005, 25 in 2000, 45 in 1990, 80 in 1975)
Line Clearing Mulchers, Chainsaws also Zero
Slash Disposal Little to no slash with mulched lines
Ground Disturbance Little to none, lines recovered within a few growing seasons
Energy Source 1/2kg – 2Kg explosive,
Vibrators and Mini Vibrators up to 4 in Tandem plus single sweep
Shot Hole Depths 5m –15m some holes were 3 or 5 hole patterns
Safety Safety training required from Enform now Energy Safety Canada, First Aid, TDG, WHIMIS, H2S, Blasting, Chainsaw Falling and additional Industry Recommended Practices
Seismic continues to evolve with newer, better equipment, smaller charge sizes required and
more sensitive geophones and nodal systems available. Data is significantly better than that acquired back in the 1960’s & 70’s. An analogy would be that of a high-definition colour TV
monitor compared to an old black & white TV screen.
Higher density of source lines and receiver lines also increases the trace density and the fold of
the stacked data which increases the signal to noise ratio giving the geophysical interpreters
cleaner data to work with to illuminate subtle amplitude variations and anomalies which may
represent reservoirs.
It also allows for better resolution of the shallower seismic events which means the seismic
could possibly be used to identify possible aquifers to obtain water for fracking or to understand
geohazards in the placement of the wells.
Stake-less surveys, cable-less autonomous recording systems, sophisticated in-cab navigation
systems with alerts and alarms when encroaching on hazards and exclusion zones have
become commonplace. Single-sweep vibrators working concurrently on lines have in some
cases tripled or quadrupled the production. Helicopters are used to move equipment to where it
is needed and UTVs and snow machines guided by cell phone navigation apps have eliminated
the need for multiple vehicle access on programs.
Regulatory & environmental pressures on the seismic industry to further reduce impacts persist,
(e.g. SARA species at risk, Caribou, Methane emissions, CO2, etc.) even though the industry is
already highly regulated and has spent millions of dollars to adapt to lower its footprint over the
past 25 years. I do not recall other industries such as farming amending their practices to the
same extent & relative cost.
Seismic and Oil & Gas exploration was largely responsible for the opening up of the North, and
the remote communities have greatly benefitted from the resulting development, access, jobs
and wealth created.
In 2016 Energy Safety Canada was formed with the merger of EnForm & OSSA (Oil Sands
Safety Association). The safety performance of the Oil & Gas industry is now second to none
with many oil and gas companies tying their yearly bonuses to the Health, Safety Environment
record of the company including the work done by contractors.
Thank you for sharing us this awareness, Grateful.
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geophysical vibrator