Abstract
To isolate injection and production zones from overlying formations and aquifers during geothermal operations, cement is placed in the annulus between well casing and the formation. However, wellbore cement eventually undergoes fractures due to chemical and physical stress with the resulting time and cost intensive production shutdowns and repairs. To address this difficult problem, a polymer-cement (composite) with self-healing properties was recently developed by our group. Short-term thermal stability tests demonstrated the potential of this material for its application in geothermal environments. In this work, the authors unveil some of the physical and chemical properties of the cement composite in an attempt to better understand its performance as compared to standard cement in the absence of the polymer. Among the properties studied include material's elemental distribution, mineral composition, internal microstructure, and tensile elasticity. Polymer-cement composites have relatively larger, though not interconnected, levels of void spaces compared to conventional cement. Most of these void spaces are filled with polymer. The composites also seem to have higher levels of uncured cement grains as the polymer seems to act as a retarder in the curing process. The presence of homogeneously-distributed more flexible polymer in the cement brings about 60–70% higher tensile elasticity to the composite material, as confirmed experimentally and by density-functional calculations. The improved tensile elasticity suggests that the composite materials can outperform conventional cement under mechanical stress. In addition, calculations indicate that the bonding interactions between the cement and polymer remain stable over the range of strain studied. The results suggest that this novel polymer-cement formulation could represent an important alternative to conventional cement for application in high-temperature subsurface settings.
| Original language | English |
|---|---|
| Pages (from-to) | 279-287 |
| Number of pages | 9 |
| Journal | Cement and Concrete Composites |
| Volume | 97 |
| DOIs | |
| State | Published - Mar 2019 |
| Externally published | Yes |
Funding
Funding provided by the Department of Energy’s Geothermal Technology Office . PNNL is operated by Battelle for the U.S. DOE under Contract DE-AC06-76RLO 1830 . Work at Brookhaven National Laboratory was performed using funding from Laboratory Directed Research and Development (LDRD) Program under project no 16-019. Part of this research was performed at the W.R. Wiley Environmental Molecular Sciences Laboratory (EMSL) , a national scientific user facility at PNNL managed by the Department of Energy's Office of Biological and Environmental Research, and simulations were performed using PNNL Institutional Computing. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 . This research used resources and SRX beamline (5-ID) of the National Synchrotron Light Source II, a U.S. Department of Energy Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704 . K. Chen-Wiegart and C Zhao acknowledge the support by the Department of Materials Science and Chemical Engineering, the College of Engineering and Applied Sciences, and the Stony Brook University, as well as by the Brookhaven National Laboratory under Contract No. DE-SC0012704 . Funding provided by the Department of Energy's Geothermal Technology Office. PNNL is operated by Battelle for the U.S. DOE under Contract DE-AC06-76RLO 1830. Work at Brookhaven National Laboratory was performed using funding from Laboratory Directed Research and Development (LDRD) Program under project no 16-019. Part of this research was performed at the W.R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility at PNNL managed by the Department of Energy's Office of Biological and Environmental Research, and simulations were performed using PNNL Institutional Computing. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research used resources and SRX beamline (5-ID) of the National Synchrotron Light Source II, a U.S. Department of Energy Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. K. Chen-Wiegart and C Zhao acknowledge the support by the Department of Materials Science and Chemical Engineering, the College of Engineering and Applied Sciences, and the Stony Brook University, as well as by the Brookhaven National Laboratory under Contract No. DE-SC0012704.
| Funders | Funder number |
|---|---|
| College of Engineering and Applied Sciences | |
| DOE Office of Science | |
| Department of Materials Science and Chemical Engineering | |
| U.S. Department of Energy Office of Science | |
| U.S. Department of Energy | DE-AC06-76RLO 1830, DE-AC02-05CH11231 |
| Office of Science | |
| Brookhaven National Laboratory | DE-SC0012704 |
| Laboratory Directed Research and Development | 16-019 |
| Stony Brook University |
Keywords
- Cement
- Geothermal
- Polymer
- Self-healing
- Wellbore
