Qatar Complex Porous Media Laboratory
Opened at the end of 2015, the Qatar Complex Porous Media Laboratory is the most recent addition to the QCCSRC research hub at Imperial College London. The lab is dedicated to the study of flow and storage mechanisms in porous systems, including reservoir- and cap-rocks, with relevance to CO2 storage and hydrocarbon recovery operations.
The pore space of rocks is characterised by multiple scales, ranging from fractures that are visible to naked eye down to pores of the size of a few nanometres. The latter include e.g., intra-particle microporosity in carbonate rocks or the interlayer spacing associated with clay minerals. These pores create a variety of intimate fluid-fluid and fluid-rock interactions, including adsorption, chemical reactions, wetting and capillary phenomena, and are responsible for introducing confining effects in general. These physicochemical interactions affect fluid and solute transport by controlling the mobilisation of fluids, their trapping and their phase behaviour in the porous rock. Our goal is to study these processes under realistic subsurface conditions and to use this knowledge to optimise the engineering design of subsurface operations. Our focus is on the characterisation of new challenging systems, including reactive environments (e.g., carbonates), nanoporous (e.g., mudrocks) and fractured rock systems, for which conventional single- and multi-phase concepts are not well defined, and the corresponding data set is rather scarce.
Understanding nano-confinement effects on fluid properties and behaviour is key to the characterisation of porous solids, as the latter relies on the adsorption and transport of confined fluids. Our laboratory currently hosts a state-of-the-art Magnetic Suspension Balance for high-pressure equilibrium and dynamic adsorption measurements of several gases on microporous solids up to 35 MPa and 250°C, thus mimicking conditions that exist in subsurface reservoirs. Results from these experiments are used to gain novel insight on the pore space of rocks, on the phase behaviour of fluids within their pores and to quantify storage capacities. By profitably selecting different vapours we aim at extending this characterisation to include wettability effects, something that may prove to be particularly beneficial for the characterisation of mixed-wet rocks. These data are complemented by results obtained from experiments carried out in the Qatar CCS Multi-scale Imaging Laboratory, so as to complement macroscopic observations with information on the multidimensional and inherently complex nature of these porous solids.
A customised core-flooding system has been built for the study of solute spreading and mixing in reactive and heterogeneous porous media. The system has been designed such that conventional pulse-tracer test can be carried out with the simultaneous imaging of movement of the tracer inside the rock’s pore space. To this aim, we have developed an approach that is at the forefront of current methods in reservoir core analyses and that profitably combines two non-invasive imaging techniques, namely X-ray Computed Tomography and Positron Emission Tomography. By enabling the quantitative visualisation of both temporal and spatial evolution of the full tracer plume, unprecedented insight are obtained on spreading and mixing phenomena in reactive and heterogeneous porous media.
Key research Questions:
- Can we exploit gas adsorption phenomena to further improve the characterisation of microporous mixed-wet rocks?
- Do adsorption reactions mitigate leakage through caprocks?
- Are fractures effectively conducting or are they behaving as capillary systems?
- What are the main controls on solute spreading and mixing in reactive porous systems?
- How can we use advanced reservoir core analyses to better inform reservoir models?
Looking forward: Areas Under Investigation
- Gas adsorption studies on microporous rocks
- Capillary pressure and heterogeneity in reservoir rocks
- Sub-core scale 3D permeability maps of reservoir rocks
- Solute dispersion in reactive porous media
- Convective dissolution in 3D porous media
- Pini et al. (2016) “Quantifying solute spreading and mixing in reservoir rocks using 3D PET imaging”, Journal of Fluid Mechanics, accepted for publication.
- Pini & Madonna (2016) “Moving across scales: a quantitative assessment of X-ray CT to measure the porosity of rocks” Journal of Porous Materials, 23(2): 325-38. DOI: 10.1007/s10934-015-0085-8
- Pini (2014) “Multidimensional Quantitative Imaging of Gas Adsorption in Nanoporous Solids”, Langmuir, 30(37): 10984-89. DOI: 10.1021/la502582c
- Pini (2014) “Interpretation of net and excess adsorption isotherms in microporous adsorbents”, Microporous and Mesoporous Materials, 187: 40-52. DOI: 10.1016/j.micromeso.2013.12.005