Hydrophilic (water soluble) carbon clusters are being designed by Rice researchers to sense the presence of oil that remains in old wells. The HCCs are sheets of carbon one atom thick and 60 nanometers long, with embedded molecules that will detect oil, sulfur and water and store information about how much of each they encounter along their path.
Groups led by Rice professors James Tour, Michael Wong and Mason Tomson and Rice researcher Amy Kan are collaborating on a system by which hydrophilic carbon clusters (HCC) — microscopic entities designed to sense the presence of oil — can be sent into a well by the billions and come back to the surface full of valuable information
Generally, 30 to 50 percent of the oil in a well is left downhole, because they don’t know it’s there or don’t know exactly where it is,” said Tour, the Chao Professor of Chemistry and professor of mechanical engineering and materials science and of computer science
The team’s solution is to send tagged macromolecular clusters that can pass through the deposits, mixed with saltwater or other fluids, into a well. The researchers can collect and analyze them after they return to the surface.
“Inside our clusters are small molecules that will report to us whether they’ve seen oil or water and how much of each along their paths,” Tour said. “We put a trillion of these downhole, and we’ll analyze 100,000 at the other end to get an average of what they’ve seen.”
Wong said, “We are chemically constructing these nano-sized clusters to be able to handle being exposed to high temperatures, pressures and salty conditions found in a reservoir.”
Though the clusters may take time to work themselves through the subsurface rock, they come back to the surface full of good information that may take no more than a day to analyze.
Custom versions of these “smart” clusters will be able to give the specifics of what’s in a well, he said. “We can tag them differently, much like having an internal bar code,” said Tour, who suggested regularly pumping HCCs into a well could provide constant monitoring of its status.
“We’ve got a long way to go before we know for sure if it works,” said Tomson, whose lab is working to prove the concept this summer. “Within six to nine months after that, we’ll have a pretty good idea of whether we’re on to something.”
The HCCs could be ready for oil field testing in a year or two, but commercialization is going to depend on the industry’s willingness to invest. “It’s potentially a very high-visibility project,” said Tomson, who also directs the Brine Chemical Consortium of oil and productions and service companies. “It’s just the kind of thing they would be excited about.”
BP (british petroleum) says advancements in technology — including gas injection — will likely allow it to recover 60 percent of the oil at its massive Prudhoe Bay field in Alaska. The original estimate three decades ago was 40 percent.
The nanoreporters would provide more details on where to drill and where it is worthwhile to drill.