Land seismic is a whole different world from marine, and it’s experiencing its own uptick owing in large part to the proliferation of shale gas plays in the United States.
These plays have become so ubiquitous – and productive – that natural gas storage is over the top, while prices are virtually on life support.
This is bad and yet, in a way, not so bad.
“When prices were at $14, you could almost drill anything, and the economics would work,” commented Bob Peebler, CEO at ION Geophysical. “Once prices drop, you have to look for ways to be more productive, whether in drilling wells or completing the ones you’re drilling more accurately.”
The ongoing anemic natural gas price, hovering around $4/Mcf on a good day, has prompted many players to head toward shale oil plays along with shale gas plays that have a significant liquids component.
No matter the type of production, seismic data info has become a necessity not just to try to zero in on the sweet spots but to efficiently wrest the hydrocarbons from the dense shales.
“One of the themes we’re talking about at conferences is understanding plumbing of these reservoirs,” said Steve Trammel, senior product manager at IHS in Denver.
“In the 1980s, when we were drilling horizontal in the Bakken and the play fizzled,” Trammel said, “we were saying unconventional meant uneconomical.
“In the late 1990s and 2000s, technology such as extended reach horizontal drilling, and multi-stage fracing combined with 3-D enabled greater understanding of these reservoirs,” Trammel noted.
He emphasized that seismic data are important owing to so much variability of reservoir quality in the shales.
“When you use 3-D in these resource plays, it gives you a view of the petrophysical and geomechanical properties of those reservoirs to better predict where most of the production zones are for the drill bit and for fracing the well,” Trammel noted.
“Three-D also helps to identify where the fracture swarms are, where the fracture density really is,” he added. “Also, it tells you the orientation of the fracture matrix, which helps to determine the most effective drilling direction.”
Peebler emphasized there’s significant interest in geology and geophysics.
“I think people are going back and looking at how to do more detailed geophysics and geology work and integrate it with the engineering and be more precise,” he said.
“We’re more at the beginning of that than the end,” he noted. “People are still struggling to completely understand some of the workings of these reservoirs.”
Peebler noted also that they’re seeing a trend toward more multi-client seismic surveys in the shales than proprietary shoots, which is a sensible approach given these are large areas with a lot of players.
Global Geophysical Services, which is seemingly everywhere acquiring seismic data in the shale plays these days, is big on multi-client programs.
“The bulk of our shale work is multi-client,” said AAPG member Richard Degner, president at Global. “There’s a huge economy of scale with these continuous reservoirs to record at scale over large areas and to have seamless contiguous datasets.
“The multi-client business model lends itself favorably to those areas,” Degner emphasized. “We acquire very high resolution, or reservoir grade 3-D (RG3D®), which is important to optimize what are six to eight million-dollar wells and completions.”
A non-seismic trend drawing attention in the shale arena is “the big fish swallowing the little fish,” according to Peebler.
A notable example is ExxonMobil’s announced buyout of XTO with its impressive portfolio of domestic shale gas, tight gas, coalbed methane and shale oil.
International interest in owning a piece of the action while acquiring the technology needed to develop shale plays overseas is obvious when considering the deals being cut between domestic shale players extraordinaire, e.g. Chesapeake, and other countries as well as sovereign wealth funds.
In the seismic arena, Trammel said 4-D applications are becoming common in shale plays. Sensors placed down the wellbore serve various purposes, such as tracking the success of hydraulic fractures over time.
Three-dimensional seismic is used for infill drilling all over the country, and Trammel emphasized that 3-D can potentially work wonders in abandoned fields, citing central Kansas as a good example.
“With the industry chasing liquids so heavily, they’re using 3-D to find by-passed hydrocarbons around some of these old abandoned oil fields there,” he said. “It’s a wonderful example and could have far reaching effects.
“When you consider the potential for enhanced oil recovery,” Trammel said, “one of the things we’ve studied is if we could increase oil recovery by only about 10 percent globally – which is very achievable – we will produce more oil than throughout history.”
Scott Stockton presented the paper "The Use of 3-Component Seismic Data to Identify Sweet Spots in Fractured Bakken Reservoirs" at the recent AAPG International Conference and Exhibition in Calgary, Canada.