NGFE Reports: Exploration Strategies & Technologies Pushing Shale Gas Forward

Through years of trial and error, those drilling for shale gas in North America had to bring out an arsenal of strategies and technologies to be able to locate shale gas deposits. Over time, exploration operations appear to be getting better and better.

In a session dedicated to exploration strategies and technologies, Brian Horn, Chief Geologist at Ion Geophysical gave an overview of seismic technology, which he said was evolving.

“We may need a paradigm shift,” he said, showing a map of the North American shale basins from 2007. “They weren’t really on the map but now a large percentage of shale gas production is expected to come from these plays: 70%.”

But all shale gas plays are not created equal, according to Horn, who listed several areas where exploration is making progress.

“Multilaterals can now be conducted cost effectively,” he said. “Stimulation techniques have developed significantly. And there’s an abundance of high-density wells of ‘conventional’ exploration drilling.”

The challenges, he said were geological and commercial.

“We’re looking for productivity, that’s what this is about,” he said of seismic. “Thickness, TOCs, mineralogy, among others – these all come into play.”

Mr. Horn described the activities involved in the seismic his company performs. “We map the thickness. Lots of time and money are put into understanding fractures and stress field magnitude as well as sweet spot mapping. We try to figure out why wells performing the way they are.”

“Is there a way to look at them more holistically?” he queried. “Looking at a basin, stepping back and taking a bigger perspective, offer us a view of plays that weren’t even considered. For shale gas plays is this type of data/perspective going to help us with ‘the why’? Can our ability in using seismic help us bring the cost down, if most shale plays are barely making money?”

Seismic, said Horn, allows for mapping of structure, interval thickness, faults and karsts. And can help an explorer to prioritize where to test.

He said the results have an economic impact, for example: “If you have a 640 acre leasing, are you going to drill four wells or eight?”

“Shales are not homogeneous. We can save a lot of time eliminating the areas we don’t want to go into, which can save a substantial amount of money,” continued Horn. “If we understand the attributes, perhaps we can save drilling 56 wells.”

Horn listed factors involved in try to optimize an exploration program, like basin entry, lease acquisition (which he said can be a land grab), evaluation of commerciality, acreage capture, and infill drilling.

“Seismic allows us to optimize existing technologies,” he explained. “There’s a lot of good stuff out there helping us to understand why fracs are different, or identifying sweet spots.”

Horn said he believed the integration of multiple data sets was the key to addressing those issues.

But the scarcity of seismic, and the fact that not all technologies were commercially viable were things pointed out by Neil MacTavish, Business Development Manager at ADROK, involved in scanning technology.

He offered up a likely scenario for enterprises exploring shale deposits. “Let’s say it’s a busy year and all the time the clock is ticking on your license.”

“We’re bringing new technologies to markets,” said MacTavish. “Subsurface geology – to locate gas, oil and minerals from the surface without drilling. This helps reduce the drilling of dry holes.”

He explained, “It’s actually quite simple. It’s extremely mobile and can be quickly deployed into the field. We have a version, which can be used offshore, but most are deployed on land. There is also a version that can be used in difficult terrain.”

MacTavish said Adrok’s method performs some of the tasks of seismic and some of drilling. “Ours uses electromagnetic resonance. Radio waves pass with minimum dispersion. So far it’s only been validated to a depth of four kilometres. We do a test bore for data to make a relevant comparison.”

“We measure the signal made by the agitation created by a beam of light passing through something,” he added.

“It’s portable, weatherproof in extreme conditions. The time to survey a bore hole is approximately two hours. Once we get it back to the laboratory it takes three man-days for analysis.”

MacTavish said, “The point is to offer you a high level of confidence in your results and to de-risk it. In the US, saving drilling five wells can help you save millions of dollars. In Europe it’s the utilization of very scarce drilling time, so you’re helping to confirm the play before you drill. From the environmental side, it’s non invasive.”

“We’re gone in a day, maybe two,” he said. “This ultimately leads to lower costs.”

He gave case studies of success in northern Africa and in the UK, which showed strong correlations with other measurements.

“We really are in need of some good information to complement the colleagues here,” said MacTavish of delegates at the Global Shale Gas Summit. “The environmental point of view can be addressed with a non-invasive approach until drilling is necessary.”

“Technology,” he summed up, “can give you an edge.”

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