A model to predict the elastic properties of gas hydrate-bearing sediments

Abstract

A simple and accurate model for predicting the elastic properties of gas hydratebearing sediment (GHBS) is proposed and validated against experimental data. It is developed on the basis of the homogenization theory for multiphase composite. Unlike the classical homogenization techniques those fix a homogenization scheme (e.g. self-consistent, Mori-Tanaka, DEM, etc.) for a given microstructure, the proposed model considers a flexible homogenization scheme that adapts with the change of the microstructure of the material. The idea is to modify the elastic properties of the reference matrix with respect to the microstructure change of the mixture. Such modification is ensured by adapting the theoretical method to available experimental data. The derived method is proved to be very powerful as it can fit laboratory measured data on gas hydrate-bearing sand formed by different methods including excess gas and excess water methods and log data taken from various sites. Such feature cannot be satisfied by the existent models those consider the hydrate phase as a cement phase or a porefilling phase. A very good agreement between the proposed method and experimental data offer a simple and accurate ways to predict the saturation of gas hydrate using sonic log data or 3D seismic data.

Wave Properties of Gas-Hydrate Bearing Sediments Based on Poroelasticity

“…The continuously injected water reacts with a certain amount of methane gas to form small quantities of hydrates, which are not in contact with the grains. In this case, we have the assumption of Model 1 (Best et al, 2013;Tuan et al, 2019), with hydrate concentrations less than 40% (Priest et al, 2009;Zhao et al, 2015). and 42%, respectively.…”

“…A high amount of methane gas is injected to react with water, and then gas hydrate is formed at the grain contacts or at the surface of the grains. Thus, we have the conditions of Model 2 (Best et al, 2013;Tuan et al, 2019). Figures 13, 14 compare the theoretical and experimental P-wave velocities and dissipation factors as a function of hydrate concentration around 200 Hz, respectively (the porosities are 42%).…”

“…Sell et al (2016) combine tomography and 3D modeling to simulate the acoustic properties with digital rock physics, whereas Sell et al (2018) show that there is an interfacial water film between hydrate and grains through 3D micro-tomography, and a new conceptual squirt-flow model is proposed. Tuan et al (2019) uses a homogenization theory for multiphase composites to predict wave velocities that agree with laboratory and sonic-log data.…”

New X-Ray Microtomography Setups and Optimal Scan Conditions to Investigate Methane Hydrate-Bearing Sand Microstructure

“…However, by using seismic wave velocities (Chand et al 2004;Dvorkin et al 2000;Dvorkin and Lavoie 1999;Dvorkin and Nur 1996;Helgerud et al 1999), MHs are believed to exist in four idealized arrangements or "pore-habits": cement, with graingrain contacts; cement, with mineral coating; load-bearing and pore-filling. Physical and mechanical properties of sediments containing MHs depend considerably on methane hydrate morphologies and distribution within the pore space, which are thus of the essence for interpretation of geophysical data and reservoir-scale simulations in the scope of methane gas production (Taleb et al 2018;Le et al 2019;Nguyen-Sy et al 2019;Alavoine et al 2020;Taleb et al 2020). Therefore, pore-scale observations of MH morphologies and pore-habits in sandy sediments are crucial.…”

Two-step Homogenization of Poroelastic Properties of a Limestone

“…The composite sphere assemblage (CSA) models proposed by Hashin (Hashin, 1962) (Eshelby, 1957) coupling with a homogenization scheme (e.g. Non-interaction (Shafiro et al, 2000); Mori-Tanaka (Mori & Tanaka, 1973); Differential (Norris, 1985; Nemat-Nasser & Hori, 1999); Self-consistent (Hill, 1965;Vu, 2012Vu, , 2018; Differential Self-consistent (Norris, 1985;Zimmerman, 1996); Iterative Self-consistent (Zouari et al, 2008); Adaptative (Nguyen et al, 2016(Nguyen et al, , 2019, Hashin et Strickman borns (Hashin & Shtrikman, 1962, 1963, etc.) is proper for the low and moderate volume fraction of grains.…”