Permeability Prediction in Rocks Experiencing Mineral Precipitation and Dissolution: A Numerical Study

Abstract

In this study, we focus on the electrical tortuosity‐based permeability model k = reff2/8F (reff is an effective pore size, and F is the formation factor) and analyze its applicability to rocks experiencing mineral precipitation and dissolution. Two limiting cases of advection‐dominated water‐rock reactions are simulated, that is, the reaction‐limited and transport‐limited cases. At the pore scale, the two precipitation/dissolution patterns are simulated with a geometrical model and a phenomenological model. The fluid and electric flows in the rocks are simulated by directly solving the linear Stokes equation and Laplace equation on the representative elementary volume of the samples. The numerical results show that evolutions of k and F differ significantly in the two limiting cases. In general, the reaction‐limited precipitation/dissolution would result in a smooth variation of k and F, which can be roughly modeled with a power function of porosity ϕ with a constant exponent. In contrast, the transport‐limited precipitation/dissolution mostly occurs near the pore throats where the fluid velocity is high. This induces a sharp change in k and F despite a minor variation in ϕ. The commonly used power laws with constant exponents are not able to describe such variations. The results also reveal that the electrical tortuosity‐based permeability prediction generally works well for rocks experiencing precipitation/dissolution if reff can be appropriately estimated, for example, with the electrical field normalized pore size Λ. The associated prediction errors are mainly due to the use of electrical tortuosity, which might be considerably larger than the true hydraulic tortuosity.

Hydraulic and Mechanical Impacts of Pore Space Alterations within a Sandstone Quantified by a Flow Velocity-Dependent Precipitation Approach

“…By contrast, uniform mineral growth around the grains represents a surface reaction-controlled process [ 74 ], whereby the chemical reaction rate limits precipitation and the pore space is altered homogeneously. Both spatial precipitation patterns have been observed in several laboratory [ 19 , 21 , 56 ] and numerical studies [ 18 , 80 , 81 ], investigating mostly calcite and barite precipitation in porous media. Preferential precipitation in regions of LFV can be explained by an undisturbed growth of minerals, whereby fluid shear stresses limit precipitation.…”

“…These findings lie in the range of the simulated contrasting cases of a uniform mineral growth and preferential precipitation at high flow velocities, which demonstrates the applicability of the simulated reaction- and transport-controlled precipitation process applied in the present study. Niu and Zhang [ 80 ] even found a higher value of = 30, considering a transport-limited mineral growth and concluded that a constant exponent cannot describe this process sufficiently well due to the strong permeability decrease. The Kozeny–Carman relation initially exhibits a good agreement with a uniform mineral growth around the grains.…”

The Effect of Silica Dissolution on Reservoir Properties during Alkaline-Surfactant-Polymer (ASP) Flooding

“…Secondly, it promotes a high pH environment, leading to dissolving minerals such as quartz, feldspar, and clays (Yupu et al, 2004). Several scholars have studied the formation of silicate scaling during water flood, confirming the possible reservoir damage caused by the precipitation of silica ions (Ikeda & Ueda, 2017;Niu & Zhang, 2019;Yanaze et al, 2019). A recent study by (Yanaze et al, 2019) reported a reduction in flow rates during water flooding accompanied by a significant reduction in permeability due to silica precipitation.…”

Evolution of Fault-Zone Hydromechanical Properties in Response to Different Cementation Processes

“…Thus, reaction rates and the spatial distribution of reaction products should be relatively homogeneous over length scales that do not result in significant variations in temperature/kinetics (i.e., a few 10's or perhaps 100's of meters in the crust). Reaction-limited transport in both porous media and fracture networks in the crust has been inferred by a variety of experimental, numerical, and rockrecord studies [25][26][27][28][29][30][31][32] and may be particularly applicable during cementation of fracture networks when the rates of fluid advection are modest or where the precipitation reaction is kinetically limited. Thus, in a fractured but homogeneous rock mass or in a rock mass where mineralogical variations (and associated surface chemistry heterogeneities) occur over smaller spatial scales than those of fracture length, the rate of aperture decrease and fracture sealing during cementation should be approximately constant through space and time.…”