A novel method of technology development might fill in some of the research and development (R&D) gaps.

When Apache Corp. wanted a new way to create a source for land-based seismic operations, it made Calgary-based Polaris Explorer Ltd. an offer it couldn't refuse - if you build it, we'll use it.
The source method is a weight-drop system that causes a one-time burst of energy, like a dynamite shot, rather than the constant rumbling of a Vibroseis truck. The concept itself is not new, but systems of the past were difficult to control, with resulting uncertainties in accuracy and timing. Apache scientists revived the idea not to compete with Vibroseis methods but as a comparison to another source system it was testing, which entailed dropping a weight from a helicopter.

Despite the crudeness of the first experiment, geoscientists were impressed with the results. "It was better than we expected," said Dave Monk, manager of geophysics at Apache. "We thought it was worth looking into a little more seriously."

The company experimented with conventional thumper trucks for shallow engineering work. Encouraged by those results, Monk decided it was time to custom-build a machine that could be used for full-scale 3-D seismic surveys, but Apache isn't in the fabrication or engineering business.

"We went to Polaris and said, 'This is a good idea, but the machine we need to use hasn't been built yet,'" Monk said. "We told them if they built it, we would use them for our surveys. We pushed them pretty hard.
"They embarked on that construction and engineering project pretty much on their own but with an awful lot of pressure from us."

Mike Bahorich, executive vice president of E&P technology at Apache, added, "We felt that a show of good faith was in order, and if they built the machine we'd come through with the cash, which we did. They were out on a limb, frankly. But we came through."

The system, the Explorer 860, has several benefits over Vibroseis trucks. The vehicles are more agile, and the impulsive nature of the source gives much better first breaks in the data, which leads to a superior surface model.

They're also faster. "If you do a Vibroseis sweep, it takes time," Monk said. "Operationally this is a much more rapid and economic way to acquire data. That's a big issue in some areas."

The source also compares favorably to dynamite by mimicking the impulsive nature of a dynamite blast without the consequent operational and safety issues.

The vehicle uses a hydraulic system to raise and lower a weight of just over 2,600 lbs. A nitrogen gas-charged accumulator is plumbed into the top of the hydraulic cylinder. The pressure in the accumulator can be adjusted, controlling the force acting on the top of the mass when released to drive into a base plate of similar mass. Because the timing is very accurate, multiple units can be used at the same time if more energy is required.

Apache has shot three large surveys already this year, all in Canada. Monk estimated that 70% of the company's total square mileage in Canada this year was shot using the weight-drop vehicles.
Polaris does offer the system commercially, but Apache has first right of refusal on the units and plans to continue to use them on its Canadian surveys. The hope is that demand will enable Polaris to build enough units that other companies will also have access to them.

The system is ideally suited for Canadian acquisition for a number of reasons. Near-surface resolution is one. Also, the sensitive nature of the environment forces contractors to leave a minimal footprint if they hope to avoid costly permitting snags in the future. This was the rationale behind the helicopter weight drop, which would require no surface intervention at all. But the difficulty of avoiding items on the ground, particularly in areas where production facilities already exist, has relegated it to areas without infrastructure.

The Explorer 860 can maneuver in narrow cut lines, which do not have to be straight, and there is very little surface damage from the source.

Monk and Bahorich said this type of technology funding seems to fill some of the void that has existed since most of the majors stopped funding R&D. "Service companies need capital to develop new technologies, but they also need oil companies to test new products to refine them and to help them gain market acceptance," Bahorich said.

Monk added, "Polaris is not a big seismic company, and they bit off a lot here to do this development. Unless we came up with some way of helping them, I don't think it would have happened."