CAGC Column: Seismic Program Evolution & Development – High Level Summary

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

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 self-contained 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 ink-plotted 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

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 4 in tandem)
• Programmable calculators (Texas Instrument / Hewlett Packard) with data loggers became 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)

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, dog-legs)
• More Spec Companies establish to shoot programs
• 3rd Party Field Management companies programs formed

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.

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

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)

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.