Oct 26 2009
A wall of graphene a single nanometer wide could be the difference between an oil well that merely pays for itself and one that returns great profit.
Rice University and Houston-based M-I SWACO, the world's largest producer of drilling fluids for the petrochemical industry, have signed an agreement for research funds to develop a graphene additive that will improve the productivity of wells.
The company will spend $450,000 over two years for research by the lab of James Tour, Rice's Chao Professor of Chemistry and professor of mechanical engineering and materials science and of computer science.
Tour's lab will work with M-I SWACO's researchers to optimize the effectiveness of graphene additives to drilling fluids, also known as muds.
Water- or oil-based muds are typically forced downhole through a drill to keep the drillhead clean and to remove cuttings as the fluid streams back up toward the surface. But the fluids themselves can clog pores in the shaft through which oil should flow.
The nanoscaled graphene additive, just a little per barrel, would be forced by the fluid's own pressure to form a thin filter cake on the shaft wall; this will prevent muds from clogging the pores.
When the fluids are removed along with the drill head, the formation pressure -- that is, the pressure of the oil or gas inside the ground - would force the filter cake out through the pores and into the shaft. "When you release the hydrostatic pressure and pull the drill bit out, there's much more pressure inside the rock than in the hole," Tour said. "The filter blows out and the oil flows."
James Bruton, M-I SWACO's vice president for research and engineering, said the time is right for his company to investigate the use of nanoparticles. "It's something we've wanted to get into, but it was obvious we would have to partner with those who are in the know about nanotechnology. So when a friend of our CEO's who knows Professor Tour asked if we were interested in visiting with him, we were happy to say yes."
Bruton said the cost of drilling fluids can reach $200 to $300 per barrel, and a well in the Gulf of Mexico might require more than 20,000 barrels to drill. "It's not a cheap undertaking for our customers, so the performance of the fluids is paramount," he said.
Tour emphasized the nanomaterials being studied are "clean tech" components in an environmentally sensitive field. "We've shown them to be nontoxic in many forms," he said. "It's all graphite-based, and that often comes from the ground anyway."
While the company's current focus is on drilling muds, Bruton said future research would focus on using graphene in completion fluids and other drilling products. "The ideas for using nanotechnologies are endless," he said.
"People often ask me what are we developing, and most of the time they want to know what's coming out tomorrow, next week, next month or next quarter," Bruton said. "In reality, I have to worry about things we're going to implement two to five years from now. That's where the step changes are. That's where we hope and believe nanotechnology, with Rice and Jim's group, will help us get to where we need to go."