November 12, 2019

  • 11:44am

    A key part of drilling and tapping new oil wells is the use of specialized cements to line the borehole and prevent collapse and leakage of the hole. To keep these cements from hardening too quickly before they penetrate to the deepest levels of the well, they are mixed with chemicals called retarders that slow down the setting process.

    It’s been hard to study the way these retarders work, however, because the process happens at extreme pressures and temperatures that are hard to reproduce at the surface.

    Now, researchers at MIT and elsewhere have developed new techniques for observing the setting process in microscopic detail, an advance that they say could lead to the development of new formulations specifically designed for the conditions of a given well location. This could go a long way toward addressing the problems of methane leakage and well collapse that can occur with today’s formulations.

    Their findings appear in the journal Cement and Concrete Research, in a paper by MIT Professor Oral Buyukozturk, MIT research scientist Kunal Kupwade-Patil, and eight others at the Aramco Research Center in Texas and at Oak Ridge National Laboratory (ORNL) in Tennessee.

    “There are hundreds of different mixtures” of cement currently in use, says Buyukozturk, who is the George Macomber Professor of Civil and Environmental Engineering at MIT. The new methods developed by this team for observing how these different formulations behave during the setting process “open a new environment for research and  innovation” in developing these specialized cements, he says.

    The cement used to seal the lining of oil wells often has to set hundreds or even thousands of meters below the surface, under extreme conditions and in the presence of various corrosive chemicals. Studies of retarders have typically been done by removing samples of the cured cement from a well for testing in the lab, but such tests do not reveal the details of the sequence of chemical changes taking place during the curing process.

    The new method uses a unique detector setup at Oak Ridge National Laboratory called the Nanoscale Ordered Materials Diffractometer, or NOMAD, which is used to carry out a process called Neutron Pair Distribution Function analysis, or PDF. This technique can examine in situ the distribution of pairs of atoms in the material that mimic realistic conditions that are encountered in a real oil well at depth.

    “NOMAD is perfectly suited to study complex structural problems such as understanding hydration in concrete, because of its high flux and the sensitivity of neutrons to light elements such as hydrogen,” says Thomas Proffen of ORNL, a co-author of the paper.

    The experiments revealed that the primary mechanism at work in widely used retarder materials is the depletion of calcium ions, a key component in the hardening process, within the setting cement. With fewer calcium ions present, the solidifying process is dramatically slowed down. This knowledge should help experimenters to identify different chemical additives that can produce this same effect.

    When oil wells are drilled, the next step is to insert a steel casing to protect the integrity of the borehole, preventing loose material from collapsing into the well and causing blockages. These casings also prevent the oil and gas, which is under high pressure, from escaping out into the surrounding rock and soil and migrating to the surface, where leakage of methane can play a significant role in contributing to climate change. But there is always a space, which ranges up to a few inches, between the casing and the borehole. This space must be fully filled with cement slurry to prevent leakage and protect the steel lining from exposure to water and corrosive chemicals that could cause it to fail.

    Methane is a much stronger greenhouse gas than carbon dioxide, so limiting its escape is a crucial step toward limiting the contribution of oil and gas wells to global warming.

    “The methane, water, and all sorts of different chemicals down there [in the well] create a corrosion problem,” Buyukozturk says. “Also, the well bore circumferential area is next to parts of the Earth’s crust that have instabilities, so material could tumble into the hole and damage the casing.” The way to prevent these instabilities is to pump cement through the casing into the area between the well bore and the casing, which provides “zonal isolation.” The cement then provides a hydraulic seal to keep any water and other fluids away from the casing.

    But the high temperatures and pressures found at depth present an environment that is “the worst thing you can do to a material,” he says, so it is crucial to understand just how the material and its chemical properties are affected by these harsh surroundings as they do their job of sealing the well.

    This new method of studying the setting process provides a way “to precisely understand this process, so we can engineer the next generation of retardants,” says Kupwade-Patil, lead author of this paper. “These retardants are very important,” not only for protecting the environment but also for preventing serious economic losses from a damaged or leaking well. “Loss of the seal is serious, so you can’t afford to make a mistake” in the cement sealing process, he says.

    “After obtaining my PhD, about 30 years ago, my first job was to improve the quality of oil-well cementing,” says Paulo Monteiro, the Roy W. Carlson Distinguished Professor of Civil and Environmental Engineering at the University of California at Berkeley, who was not involved in this work. “At that time there were limited sophisticated characterization techniques, so it is a real pleasure to see X-ray and neutron total scattering methods being applied to study the hydration of oil-well cements in the presence of chemical admixtures.” He adds that these new methods have “the potential to guide the development of tailor-made admixtures that can significantly improve the performance of oil-well cementing.”

    The research team included Peter J. Boul, Diana Rasner and Carl Thaemlitz from Aramco Service Company and Michelle Everett, Thomas Proffen, Katharine Page, Dong Ma and Daniel Olds from Oak Ridge National Laboratory in Tennessee. The work was supported by Aramco Service Company, of Houston, and the U.S. Department of Energy. 

  • 11:44am

    A key part of drilling and tapping new oil wells is the use of specialized cements to line the borehole and prevent collapse and leakage of the hole. To keep these cements from hardening too quickly before they penetrate to the deepest levels of the well, they are mixed with chemicals called retarders that slow down the setting process.

    It’s been hard to study the way these retarders work, however, because the process happens at extreme pressures and temperatures that are hard to reproduce at the surface.

    Now, researchers at MIT and elsewhere have developed new techniques for observing the setting process in microscopic detail, an advance that they say could lead to the development of new formulations specifically designed for the conditions of a given well location. This could go a long way toward addressing the problems of methane leakage and well collapse that can occur with today’s formulations.

    Their findings appear in the journal Cement and Concrete Research, in a paper by MIT Professor Oral Buyukozturk, MIT research scientist Kunal Kupwade-Patil, and eight others at the Aramco Research Center in Texas and at Oak Ridge National Laboratory (ORNL) in Tennessee.

    “There are hundreds of different mixtures” of cement currently in use, says Buyukozturk, who is the George Macomber Professor of Civil and Environmental Engineering at MIT. The new methods developed by this team for observing how these different formulations behave during the setting process “open a new environment for research and  innovation” in developing these specialized cements, he says.

    The cement used to seal the lining of oil wells often has to set hundreds or even thousands of meters below the surface, under extreme conditions and in the presence of various corrosive chemicals. Studies of retarders have typically been done by removing samples of the cured cement from a well for testing in the lab, but such tests do not reveal the details of the sequence of chemical changes taking place during the curing process.

    The new method uses a unique detector setup at Oak Ridge National Laboratory called the Nanoscale Ordered Materials Diffractometer, or NOMAD, which is used to carry out a process called Neutron Pair Distribution Function analysis, or PDF. This technique can examine in situ the distribution of pairs of atoms in the material that mimic realistic conditions that are encountered in a real oil well at depth.

    “NOMAD is perfectly suited to study complex structural problems such as understanding hydration in concrete, because of its high flux and the sensitivity of neutrons to light elements such as hydrogen,” says Thomas Proffen of ORNL, a co-author of the paper.

    The experiments revealed that the primary mechanism at work in widely used retarder materials is the depletion of calcium ions, a key component in the hardening process, within the setting cement. With fewer calcium ions present, the solidifying process is dramatically slowed down. This knowledge should help experimenters to identify different chemical additives that can produce this same effect.

    When oil wells are drilled, the next step is to insert a steel casing to protect the integrity of the borehole, preventing loose material from collapsing into the well and causing blockages. These casings also prevent the oil and gas, which is under high pressure, from escaping out into the surrounding rock and soil and migrating to the surface, where leakage of methane can play a significant role in contributing to climate change. But there is always a space, which ranges up to a few inches, between the casing and the borehole. This space must be fully filled with cement slurry to prevent leakage and protect the steel lining from exposure to water and corrosive chemicals that could cause it to fail.

    Methane is a much stronger greenhouse gas than carbon dioxide, so limiting its escape is a crucial step toward limiting the contribution of oil and gas wells to global warming.

    “The methane, water, and all sorts of different chemicals down there [in the well] create a corrosion problem,” Buyukozturk says. “Also, the well bore circumferential area is next to parts of the Earth’s crust that have instabilities, so material could tumble into the hole and damage the casing.” The way to prevent these instabilities is to pump cement through the casing into the area between the well bore and the casing, which provides “zonal isolation.” The cement then provides a hydraulic seal to keep any water and other fluids away from the casing.

    But the high temperatures and pressures found at depth present an environment that is “the worst thing you can do to a material,” he says, so it is crucial to understand just how the material and its chemical properties are affected by these harsh surroundings as they do their job of sealing the well.

    This new method of studying the setting process provides a way “to precisely understand this process, so we can engineer the next generation of retardants,” says Kupwade-Patil, lead author of this paper. “These retardants are very important,” not only for protecting the environment but also for preventing serious economic losses from a damaged or leaking well. “Loss of the seal is serious, so you can’t afford to make a mistake” in the cement sealing process, he says.

    “After obtaining my PhD, about 30 years ago, my first job was to improve the quality of oil-well cementing,” says Paulo Monteiro, the Roy W. Carlson Distinguished Professor of Civil and Environmental Engineering at the University of California at Berkeley, who was not involved in this work. “At that time there were limited sophisticated characterization techniques, so it is a real pleasure to see X-ray and neutron total scattering methods being applied to study the hydration of oil-well cements in the presence of chemical admixtures.” He adds that these new methods have “the potential to guide the development of tailor-made admixtures that can significantly improve the performance of oil-well cementing.”

    The research team included Peter J. Boul, Diana Rasner and Carl Thaemlitz from Aramco Service Company and Michelle Everett, Thomas Proffen, Katharine Page, Dong Ma and Daniel Olds from Oak Ridge National Laboratory in Tennessee. The work was supported by Aramco Service Company, of Houston, and the U.S. Department of Energy. 

October 28, 2019

  • 4:43pm

    René Andrés García Franceschini grew up in Ponce, Puerto Rico. His parents both work in science — his mother is a medical technologist, and his father is a chemist in Waco, Texas. He has two brothers, one older and one younger. When Hurricane Maria devastated the island last year, he had just started his junior year at MIT. He wasn’t able to reach his mother and siblings for about a week.

    “That kind of woke something in me,” he says. “I realized I need to try to ensure that the work that I’m doing, the technical work, is also aligned with trying to help people back home.”

    That’s when García Franceschini, a civil and environmental engineering major, reached out to the Priscilla King Gray Public Service Center. Through their pilot program PKG Explore, he spent the 2018 Independent Activities Period traveling through southern Puerto Rico learning about the experience of residents, specifically those with small to medium-size businesses, and trying to understand how the supply chain of essential goods collapsed and what could be done to improve responses in the future. He interviewed more than 50 people, ranging from farmers to shopkeepers to managers at FEMA.

    In his conversations, the one bottleneck everyone kept bringing up was energy. He and a friend applied for and received a Davis Projects for Peace Fellowship to work on an energy-sharing solution for residential units that had installed solar arrays. That first project didn’t pan out because of legal complications, but García Franceschini knew he wanted to keep working on energy solutions. He eventually discovered Solstice, a company co-founded by MIT alumna Steph Speirs, which aims to expand solar energy access to all Americans.

    “I found their mission really fascinating,” says García Franceschini, who worked for Solstice last summer as a data analyst fellow.

    Developers in community solar projects tend to ask for a FICO credit score that is above a certain number. People with lower incomes often have lower scores, even if they’re able to pay, García Franceschini explains. Using machine-learning models, Solstice created a metric to be used in place of FICO credit scores — one that is more inclusive of people with low to moderate incomes. He continues to support the implementation of the metric and work on logistics through a series of pilot projects.

    “It was … a really cool way to combine a lot of very disparate interests that I had,” he says. The experience combined “the whole renewable energy aspect, with social equity and social entrepreneurship, with things that are specifically geared toward low- to moderate-income Americans.”

    Supporting fellow students with S3

    In the fall of his sophomore year, García Franceschini was dealing with depression. He decided to go on leave for the rest of the academic year.

    “I look back at it with a little bit of sadness,” he says. “It was the first time that I showed my parents around my school, and it was to pick me up.”

    When he came back to MIT, he joined the Returning Students Group, a community organized by Student Support Services, consisting of students coming back from leave. He says Student Support Services, or S3, played a crucial role in helping him transition back into student life.

    “Going on leave was a really important part of my MIT experience. It was also not a very pleasant one,” he says, about the difficulty of making the decision to leave campus and the process of moving back home. “They really helped me through that process. … Even now I really can’t thank them [S3] enough for, for everything that they did for me.”

    García Franceschini is now a leave/return mentor, meaning he advises students who are considering going on leave. This program evolved out of a 2015-2016 review of the withdrawal and readmission practices and ensures there is an extended network of support for students thinking about taking leave, on leave, or planning a return to MIT. S3 also holds a lunch for students coming back from leave every semester, and he has served as a panelist every semester since his own return.

    “I notice that every time I serve on this panel, it gets harder and harder for me to recall the exact experiences I went through,” he says. “And I think that shows that, although the transition is definitely difficult, after a while you’re no different than students that haven’t left.”

    On the CASE

    García Franceschini had come into MIT hoping to study physics, and later declared chemistry as his major. While on leave after his first year, teaching computer science back home at Puerto Rico, he had a change of heart.

    “I realized that, for me the actual human impact that I have is equally, if not more, important than the technical rigor of the work that I’m doing,” he says.

    When he returned to school, he changed his major to civil and environmental engineering. He also discovered a group called CASE, which stands for Class Awareness Support and Equality. It was a club designed to help people at MIT who were struggling financially, and to discuss issues related to socioeconomic class.

    “So, I was like … I want to be a part of this,” he says.

    He joined the club in 2016 as funding coordinator and became president the next year, a position that he still holds. Through CASE, he and the other members have hosted workshops on socioeconomic class and financial literacy, and have worked on projects to help people with challenges such as food insecurity, budgeting, and finding housing for their parents during commencement.

    García Franceschini is also a member of the Bernard M. Gordon-MIT Engineering Leadership Program, or GEL. The program involves taking classes about leadership and reinforcing those lessons at the end of each week by having students practice the skills they’ve learned.

    “It’s been really eye-opening, as a way of assessing myself and assessing what I’m good at, and assessing what I need to improve on,” he says. The GEL office has also become his favorite secret spot on campus. “No one’s ever there, and it’s really nice!” he says.

    His fraternity, Theta Delta Chi, has also been a significant part of his life at MIT. He joined during his first year at MIT and has been an officer every semester that he’s been in TDC. He’s matured a lot because of living at the house, he says, and it’s where he found many of his best friends. Since moving off campus, he’s also taken up biking — something he didn’t know how to do until this summer when he started working at Solstice.

    “I just realized, wow, I really missed out on a lot in those 21 years when I did not know how to bike,” he says.

    García Franceschini hasn’t made up his mind about what he wants to do after graduation. While he might remain at Solstice, he’s interested in graduate programs that apply data science and statistics toward social equity programs.

    “Even if I were applying the same techniques, I know I would not be happy just doing machine learning [alone],” he says. “I also know I wouldn’t be happy just doing policy work without the technical foundation; it has to be kind of a combination of both.”