Aging of Oil/Gas-Bearing Sediments, Their Compressibility, and Subsidence

Silica polymer bonding of stressed silica grains: An early growth of intergranular tensile strength

“…19,6,5,43 This finding is also relevant to the question of short-term aging of soils for geotechnical use, and a proper conduction of oedometer compression tests to better represent soil compressibility in situ. 24 There is a host of new questions raised by the presented work. The first among them is, whether the observed intergranular silica polymer bonding spontaneously building at the intergranular damage site, is sufficient to account for the time dependent strengthening of sediments observed by Hueckel et al 24,26 The current answer is yes, the measured forces are 2-3 times higher than capillary force, classically believed to be responsible for the apparent cohesion increase upon desaturation.…”

“…24 There is a host of new questions raised by the presented work. The first among them is, whether the observed intergranular silica polymer bonding spontaneously building at the intergranular damage site, is sufficient to account for the time dependent strengthening of sediments observed by Hueckel et al 24,26 The current answer is yes, the measured forces are 2-3 times higher than capillary force, classically believed to be responsible for the apparent cohesion increase upon desaturation. Another question refers to further evolution of the polymer bridges and their strength, their possible solidification and possible interactions with other processes.…”

“…Anderson and Stokoe 3 found that coarse sands exhibit a low-amplitude shear modulus that of loose sand increased with time after blasting. 16 Also in the laboratory, Hueckel et al 24,26 have shown a nearly 50% increase in stiffness of saturated core samples from 1000 and 3000 m depth subject for an over a 14 day aging under an in situ stress.…”

“…One of an early proposed hypotheses, supported by a laboratory evidence 15 was that silica precipitates and forms a thin film of silicic acid gel on top of undisturbed silica layer which acts as cementing bonds that provide adhesion force between sand grains see also. 39,31,24,22 Experiments showed that a thin film of silanol and silicic acid chains would develop on amorphous silica surfaces in the presence of water, 48 see also. 9,10 During prolonged loading of saturated sand, it is found that continual dissolution of minerals and some precipitation of carbonates and silica would occur.…”

Feedback mechanisms in chemo-mechanical multi-scale modeling of soil and sediment compaction

“…In addition to the coupling of the fluid flow and solid deformation, specific physico-chemical processes at grain contact, e.g. diffuse double layer transport in clay [14,15], as well as stress and/or damage-enhanced dissolution of minerals [16,17,9] appear to be involved. Indeed, compaction originates at a scale of a inter-grain contact and it is often driven by the variables at the corresponding or even smaller scale: that of the molecular mass of mineral dissolution.…”