H067-01
key controls and impacts of reaction-driven alteration of fracture-matrix interface
key controls and impacts of reaction-driven alteration of fracture-matrix interface
Wednesday, 9 December 2020: 07:00
Virtual
Abstract:
The interface between fracture and matrix represents one of the hotspots where
geochemical gradients are most significant in fractured porous media. Chemical
reactions at the interface can trigger complex physical-chemical feedback. These
processes alter fracture morphology, mass transfer between the matrix and the fracture,
and thus the performance of various subsurface applications as well as their potential environmental impacts.
geochemical gradients are most significant in fractured porous media. Chemical
reactions at the interface can trigger complex physical-chemical feedback. These
processes alter fracture morphology, mass transfer between the matrix and the fracture,
and thus the performance of various subsurface applications as well as their potential environmental impacts.
This presentation will provide an overview of recent integrated experimental
and modeling studies on reaction-driven alteration of fracture-matrix interface. A
reduced-dimension reactive transport model was developed and tested based on high
pressure fracture flow experiments. The model captured the development of a porous
altered layer at the interface due to preferential mineral dissolution. By integrating an
analytical representation of diffusive transport through the altered layer, the model
reproduced fracture morphological change and bulk fluid chemistry evolution. Further
numerical experiments revealed the shift of flow regimes corresponding to different
fracture dissolution patterns as a result of the interface dynamics. Recent application of
a real rock microfluidic cell for an in operando synchrotron experiment provided a more
detailed picture of the evolution of the fracture-matrix interface. The data highlighted the
textural and mineralogical changes accompanying the altered layer development, which
can have important implications for trace element (e.g. As) migration. The dataset also
enables the development and testing of reactive transport models for full description of
local fluid chemistry, reactive mineral surface area, etc. that are critical for quantitative
assessment of the release of hazardous trace elements following the alteration at the
interface.
and modeling studies on reaction-driven alteration of fracture-matrix interface. A
reduced-dimension reactive transport model was developed and tested based on high
pressure fracture flow experiments. The model captured the development of a porous
altered layer at the interface due to preferential mineral dissolution. By integrating an
analytical representation of diffusive transport through the altered layer, the model
reproduced fracture morphological change and bulk fluid chemistry evolution. Further
numerical experiments revealed the shift of flow regimes corresponding to different
fracture dissolution patterns as a result of the interface dynamics. Recent application of
a real rock microfluidic cell for an in operando synchrotron experiment provided a more
detailed picture of the evolution of the fracture-matrix interface. The data highlighted the
textural and mineralogical changes accompanying the altered layer development, which
can have important implications for trace element (e.g. As) migration. The dataset also
enables the development and testing of reactive transport models for full description of
local fluid chemistry, reactive mineral surface area, etc. that are critical for quantitative
assessment of the release of hazardous trace elements following the alteration at the
interface.