Workers adjust piping during a natural gas hydraulic fracturing operation at an Encana Oil & Gas Inc. drilling site in western Colorado. (Brennan Linsley/AP)
The oil and gas industry’s water problem has led to a rush of ideas to use alternatives.
One of them, presented at an energy conference in Houston Thursday, involves using natural gas to produce natural gas (or oil).
Other efforts to cut down on water use — a typical well in the Eagle Ford Shale uses about 6 million gallons of water — have focused on using materials like carbon dioxide or nitrogen to create a foam substitute. Those foams can be used to fracture underground rocks, helping to release oil and natural gas trapped inside.
But David Vandor, chief technology officer for Expansion Energy, argued that using a form of natural gas makes more sense than water or other alternatives. He spoke at the World Oil Shale Energy Technology Conference, which is taking place this week at Norris Conference Centers in CityCentre.
“In effect, you can say that the introduction of those materials is a contaminant,” Vandor said. “It’s not what’s within the well. The basic principle that we’ve been pursing is to go after the hydrocarbons in the well with a hydrocarbon that is not a contaminant.”
Expansion Energy’s approach is unusual, involving what the company calls cold-compressed natural gas instead of water or other materials.
A separate effort to use a water alternative for fracturing has incorporated hydrocarbon substances, such as the natural gas liquids propane and butane, but not lighter natural gas components like methane.
Expansion Energy’s approach, which has not been tested in the field yet, would create what Vandor described as a “dense fog” of compressed natural gas that would be mixed with other substances to develop a foam.
The foam would incorporate the same types of sand used in fracturing processes of other wells.
Vandor said the approach would allow oil and gas companies to fracture underground formations and produce hydrocarbons with some key advantages.
“Certainly the natural gas that you use to create the process comes back,” he said. “That’s a good thing because what you’ve done is you’ve loaned the natural gas to create the process. You didn’t use it up.”
Traditional hydraulic fracturing results in large amounts of wastewater that need to be either treated or disposed of because of contaminants involved in the fracturing or production process.
The Expansion Energy process still would result in water produced from the well, but would not involve huge amounts of fresh water to be combined with chemicals and sand, then put into wells, removing the environmental strain and post-fracturing water treatment involved, Vandor said.
The process would also involve substituting much of the equipment at a well site with a plant that could cool and compress natural gas for use in wells. That plant also would be able to cool, compress or treat natural gas that comes out of the well, Vandor said.
Expansion Energy executives could not fully answer questions about how much gas would be required for a well and how much water would be saved with this process. Attendees at the Shale Energy Technology Conference also asked about the cost-per-barrel and how effective the natural gas foam would be at fracturing, when compared with water.
Source : fuelfix
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