@article{LiSpangenbergSchicksetal.2022,
  author    = {Li, Zhen and Spangenberg, Erik and Schicks, Judith Maria and Kempka, Thomas},
  title     = {Numerical simulation of hydrate formation in the LArge-Scale Reservoir Simulator (LARS)},
  series = {Energies : open-access journal of related scientific research, technology development and studies in policy and management},
  volume    = {15},
  journal   = {Energies : open-access journal of related scientific research, technology development and studies in policy and management},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1996-1073},
  doi       = {10.3390/en15061974},
  pages     = {27},
  year      = {2022},
  abstract  = {The LArge-scale Reservoir Simulator (LARS) has been previously developed to study hydrate dissociation in hydrate-bearing systems under in-situ conditions. In the present study, a numerical framework of equations of state describing hydrate formation at equilibrium conditions has been elaborated and integrated with a numerical flow and transport simulator to investigate a multi-stage hydrate formation experiment undertaken in LARS. A verification of the implemented modeling framework has been carried out by benchmarking it against another established numerical code. Three-dimensional (3D) model calibration has been performed based on laboratory data available from temperature sensors, fluid sampling, and electrical resistivity tomography. The simulation results demonstrate that temperature profiles, spatial hydrate distribution, and bulk hydrate saturation are consistent with the observations. Furthermore, our numerical framework can be applied to calibrate geophysical measurements, optimize post-processing workflows for monitoring data, improve the design of hydrate formation experiments, and investigate the temporal evolution of sub-permafrost methane hydrate reservoirs.},
  language  = {en}
}
@article{WetzelKempkaKuehn2018,
  author    = {Wetzel, Maria and Kempka, Thomas and K{\"u}hn, Michael},
  title     = {Quantifying rock weakening due to decreasing calcite mineral content by numerical simulations},
  series = {Materials},
  volume    = {11},
  journal   = {Materials},
  number    = {4},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1996-1944},
  doi       = {10.3390/ma11040542},
  pages     = {19},
  year      = {2018},
  abstract  = {The quantification of changes in geomechanical properties due to chemical reactions is of paramount importance for geological subsurface utilisation, since mineral dissolution generally reduces rock stiffness. In the present study, the effective elastic moduli of two digital rock samples, the Fontainebleau and Bentheim sandstones, are numerically determined based on micro-CT images. Reduction in rock stiffness due to the dissolution of 10\% calcite cement by volume out of the pore network is quantified for three synthetic spatial calcite distributions (coating, partial filling and random) using representative sub-cubes derived from the digital rock samples. Due to the reduced calcite content, bulk and shear moduli decrease by 34\% and 38\% in maximum, respectively. Total porosity is clearly the dominant parameter, while spatial calcite distribution has a minor impact, except for a randomly chosen cement distribution within the pore network. Moreover, applying an initial stiffness reduced by 47\% for the calcite cement results only in a slightly weaker mechanical behaviour. Using the quantitative approach introduced here substantially improves the accuracy of predictions in elastic rock properties compared to general analytical methods, and further enables quantification of uncertainties related to spatial variations in porosity and mineral distribution.},
  language  = {en}
}
@misc{KuehnKempkadeLuciaetal.2017,
  author    = {K{\"u}hn, Michael and Kempka, Thomas and de Lucia, Marco and Scheck-Wenderoth, Magdalena},
  title     = {Dissolved CO2 storage in geological formations with low pressure, low risk and large capacities},
  series = {Energy procedia},
  volume    = {114},
  journal   = {Energy procedia},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1876-6102},
  doi       = {10.1016/j.egypro.2017.03.1607},
  pages     = {4722 -- 4727},
  year      = {2017},
  abstract  = {Geological CO2 storage is a mitigation technology to reduce CO2 emissions from fossil fuel combustion. However, major concerns are the pressure increase and saltwater displacement in the mainly targeted deep groundwater aquifers due to injection of supercritical CO2. The suggested solution is storage of CO2 exclusively in the dissolved state. In our exemplary regional case study of the North East German Basin based on a highly resolved temperature and pressure distribution model and a newly developed reactive transport coupling, we have quantified that 4.7 Gt of CO2 can be stored in solution compared to 1.5 Gt in the supercritical state.},
  language  = {en}
}