Offshore oil production is an exercise in extremes. Widely varying temperatures, very high pressures and extremely corrosive seawater – all are challenges that producers must tackle when drilling and installing wells in ultra-deep water offshore.
Add to this list the basic inaccessibility of the wells themselves. With the top of these wells often sitting thousands of feet under water, monitoring their overall health is another major challenge.
To address this issue, Cumaraswamy “Vipu” Vipulanandan, professor of civil engineering and director of the Center for Innovative Grouting Materials and Technology (CIGMAT) with the University of Houston Cullen College of Engineering, is developing a new type of cementing slurry that will enable offshore oil rig operators to easily monitor the health of a well, both during its construction and then throughout its operational life. He has recently won a more than $2.5 million, 3-year grant from the non-profit Research Partnership to Secure Energy for America, (RPSEA) and funded by the U.S. Department of Energy (DOE), to conduct this work. Oil Field services firm Baker Hughes is providing additional funding of $500,000 as a cost share.
This new technology rests on additions to the standard drilling mud and cementing slurry used by operators to construct and form the actual well. Vipulanandan is adding new materials to the slurry, including nano-scale particles of calcium, silica and iron. Other modifiers include polymers, coupling agents, water reducing agents, particle fillers and admixtures. These additions, he said, will turn the drilling mud and cementing slurry into piezomaterials, meaning their electrical properties will change when they encounter mechanical stresses, temperature changes and chemical reactions.
Under this design, during well construction electrical leads will be placed in the outer casing of the well. As the slurry is poured to form the inner wall of the well, the sensors will be used to monitor how quickly the slurry is hardening, how much of the well has been completed and if the process is going as intended.
“Sometimes there is a crack in the deep rock formation that allows the slurry to escape. Since the company constructing the well cannot monitor this process, it may take a long time to realize there is a problem,” said Vipulanandan. “With this new technology, the sensors will show quickly that the slurry level is not rising. That way the builder can halt construction and start working on a solution.”
The new cementing mixture will allow operators to monitor operational wells, too, since it will retain its piezoresistive nature after the slurry hardens. When the hardened cement encounters a mechanical stress or strain, the technology’s sensing and monitoring capabilities will make it easy to detect and locate structural problems, such as a crack in the cemented well, allowing the operators to monitor the health of the well throughout its operational life.
Vipulanandan’s collaborators on this grant include Ramanan Krishnamoorti, chair of the UH Department of Chemical and Biomolecular Engineering, as well as Guido Gustavo Narvaez and Qi Qu , both researchers with Baker Hughes.