Energy Systems Division

Geothermal Materials Group

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Underground energy storage system

The aim of the project is to facilitate combining energy production (solar, wind) and energy storage, to smooth out fluctuations in energy production caused by changing weather and time of a day, reduce demand charges, and provide clean energy to the grid when it is most valuable, through development of innovative cementitious materials that enable economical and resilient natural energy storage.

The critical parameter for the well integrity in geothermal storage and production wells subjected to frequent thermal shocks (TS) is the interface between metal casing and cement composite. One of the pathways to a stable durable interfacial bond is the use of properly formulated lightweight composites. Since the lightweight hydrated cements made from low-density slurries have low Young’s modulus, their important benefit is high flexibility that helps to avoid debonding of cement sheath from CS during repeated compressive- and tensile-stresses under TS cycles, thereby maintaining interfacial bond integrity at cement/casing joints through control of the sheath’s radial displacement. Another important benefit of lightweight cements is their insulating property that is critical to minimize heat losses during the storage and production. And we showed that the key factor in averting interfacial debonding is the nature of cement hydration products formed in the critical interfacial boundary regions between cement sheath and casing; namely, the ideal product is an amorphous and not a crystalline phase.

Based on the above information, to achieve a durable solution for the energy storage wells the objective of this project is to develop formulas of Thermally Insulating Lightweight Thermal Shock Resistant Cements (TILTSRC), to characterize their specific properties, to conduct 6-mo.-long in-house monitoring tests for thermal conductivity and TS resistance and post-test analyses for validating the integrity of developed TILTSRC composites after repeated TS cycles.

Target materials will have to meet the following stringent criteria: 1) slurry density in the range of 1.0 to 1.4 g/cm3; 2) compressive strength >500 psi and YM: 100 x 103 to 300 x 103 psi after three TS cycles; 3) at least 2% linear expansion during the TS cycling; 4) sheath-shear bond strength > 50 psi and bond toughness represented by adhesive strain extension >2.0% after 3 TS cycles; 5) stability of air-bubbles and hollow microspheres in composite slurry at pressure of 1200 psi and 85oC; and, 6) TC value <0.4 W/mK under water-saturated conditions after 3 TS cycles.

Several innovative approaches needed to reach the ambitious goals of the project are studied: 1) Super-hydrophobic cement, improving thermal insulation (graphene and polymethyl hydrogen siloxane); 2) Improved mechanical properties of very light-weight cement (polymeric fibers, low temperatures, graphene at high T); 3) Super-ductile corrosion-resistant cement adhesive to metal (organic and inorganic additives).

Selected Publications

Sugama, T. & Pyatina, T. Alkali-activated cement composites for high temperature geothermal wells. (Scientific Research Publishing, Inc., 2017).

 Sugama, T. & Pyatina, T. Self-healing, re-adhering, and carbon-steel corrosion mitigating properties of fly ash-containing calcium aluminum phosphate cement composites at 300oC hydrothermal temperature. Cement and Concrete Composites, 99, 1-16 (2019).

 Sugama, T., Pyatina, T., Redline, E., McElhanon J., Blenkenship, D. Degradation of different elastomeric polymers in simulated geothermal environments at 300oC. Polymer Degradation and Stability, 120, 328-339 (2015).

 Sugama, T & Pyatina, T. Effect of sodium carboxymethyl cellulose on water-catalized self-degradation of 200oC-heated alkali-activated cement. Cement and Concrete Composites, 55, 281-289 (2015).

 Sugama, T., Gill S., Ecker, L., Butcher, T., and Bour, D. Susceptibility of Granit Rock to scCO2/Water at 200o and 250oC. GRC Transactions 35, 539-545 (2011).

Sugama, T. High-performance Coating Materials. DOI;10.2172/909954, BNL-77900-2007-IR.