Rice University lab's devices clarify how dispersants modify asphaltene to keep pipes open
It sounds cliché, but things do get worse before they get better when oil and gas lines are being cleared of contaminants, according to Rice University researchers. Until now, nobody knew exactly why.
Asphaltene is a complex of hydrocarbon molecules found in crude oil. It is the source of valuable asphalt and can also be made into waterproofing and roofing materials, corrosion inhibitors and other products, but when it builds up in a pipeline, it's trouble. Asphaltenes are often called the "cholesterol" of the oil industry since they are known to coagulate and slow or even stop the flow of oil and gas in reservoir rock.
Rice engineer Sibani Lisa Biswal and her colleagues used their unique microfluidic devices, instruments that use a small amount of fluid on a microchip to perform a test, to examine four commercial chemical dispersants that curtail the buildup of asphaltene in wells and pipelines. The devices allowed them to watch how the dispersants react with asphaltenes.
The Rice-led study appears in the American Chemical Society journal Energy and Fuels.
Ensuring flow through pipelines is paramount in oil and gas production, so advances that help keep lines clear are important to the industry. To date, chemical companies have generally performed static bulk tests on anti-asphaltene products, Biswal said.
The Rice lab makes microfluidic devices with microscopic channels through which researchers can watch the dynamics of asphaltene deposition in real time, with or without dispersants and at a variety of flow rates.
"Everything in our system is transparent," Biswal said. "Crude oil hasn't been very compatible with the microfluidic devices others are using (because the channels and pillars are too wide), and the type of devices we're making have only been possible with recent materials. We're one of the early groups to push the idea that we can use these systems to visualize oil flow processes
The devices allow oil to flow around pillars that are only 125 microns wide and leave channels that are roughly the size of those in oil-bearing formations. Through a microscope, Biswal and lead author and Rice graduate student Yu-Jiun Lin watched as asphaltene formed delta-shaped clumps in front of and behind the pillars, eventually filling in the channels.
When chemical dispersants were added to the crude, the researchers saw something they didn't expect: The deposits appeared even sooner, but then began to break down and fall away in the flow.
Dispersants are designed to make asphaltene particles smaller, and the experiments proved they do. "The idea is, if you make the crude oil nanoparticles smaller, it's less likely that they're going to be able to deposit inside a pipeline or plug porous media," Biswal said.
"But almost all tests up to now have been done on a bulk scale and very few under flowing conditions. Companies were just seeing if their chemicals make particles smaller. And they do. What they didn't understand is that the smaller the particle is, the less likely it's going to follow the fluid stream. In the presence of dispersants, deposits can actually get worse."
The saving grace, she said, is that dispersants appear to chemically alter asphaltene by increasing repulsion between the aggregates. That makes it more difficult for particles to stick together. "We refer to them as softer asphaltenes," Biswal said. "It doesn't take much force to break up large aggregates."
Lin said dispersant manufacturers typically use liters of crude oil in each test. "We just need a milliliter of crude, and we get better resolution than they do," he said. "When the asphaltene content is very low, traditional methods fail to see a difference in chemicals, or even a deposit."
Co-authors of the paper are postdoctoral researcher Peng He, lecturer Mohammad Tavakkoli and Francisco Vargas, an assistant professor of chemical and biomolecular engineering, all from Rice; Nevin Thunduvila Mathew, Yap Yit Fatt and Afshin Goharzadeh of the Petroleum Institute, Abu Dhabi, United Arab Emirates; and John Chai, a professor of engineering and technology at the University of Huddersfield, United Kingdom. Biswal is an associate professor of chemical and biomolecular engineering and of materials science and nanoengineering.
The Abu Dhabi National Oil Co., the Abu Dhabi Oil research and development subcommittee and the Petroleum Institute supported the research.
Read the abstract at http://pubs.
Follow Rice News and Media Relations via Twitter @RiceUNews
VIDEO CAPTION: Rice University researchers employ microfluidic devices to show how and why dispersants are able to break up deposits of asphaltene that hinder the flow of crude oil in wellheads and pipelines. In this time-lapse video, at top, as crude oil without dispersant flows through a device, deposits build up on the front and back of microscopic pillars. At bottom, with dispersant added, softened asphaltenes build up on the pillars and are then broken up by the flowing oil. (Credit: Biswal Lab/Rice University)
Asphaltene analysis takes a giant step: http://news.
Vargas Research Laboratory: http://www.
Rice Department of Chemical and Biomolecular Engineering: https:/
Rice Department of Materials Science and NanoEngineering: https:/
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,879 undergraduates and 2,861 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for quality of life and for lots of race/class interaction and No. 2 for happiest students by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.
David Ruth | EurekAlert!
Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences