Maximization of wave motion within a hydrocarbon reservoir for wave-based enhanced oil recovery

A framework for assessing the uncertainty in wave energy delivery to targeted subsurface formations

“…The laboratory and analytical investigations into the release of trapped particles from the pores of geological formations (Beresnev and Johnson, 1994;Kouznetsov et al, 1998;Roberts et al, 2001;Kostrov and Wooden, 2002;Vogler and Chrysikopoulos, 2002;Iassonov and Beresnev, 2003;Pride et al, 2008;Roberts and Abdel-Fattah, 2009;Beresnev and Deng, 2010;Beresnev et al, 2000;Manga et al, 2012;Lo et al, 2012;Deng and Cardenas, 2013) suggest that an estimate of the fluid motion in the target formation can lead to a better assessment of the particle mobilization phenomenon. In order to estimate the fluid motion generated due to the applied stress wave stimulation, in this section, we consider the case of a poroelastic target inclusion (Ω a , Fig.…”

“…Alternatively, the problem can be cast as a search for the optimal spatio-temporal characteristics of the wave sources. This approach formally gives rise to an inverse source problem (Jeong et al, 2015;, which, upon resolution, yields optimal source time signals and locations that maximize the chosen motion metric of the target region. Time reversal (TR) is another technique that can be used to focus energy in the region of interest (Anderson et al, 2008;Ulrich et al, 2009).…”

Source parameter inversion for wave energy focusing to a target inclusion embedded in a three‐dimensional heterogeneous halfspace

“…We use the adjoint force vectors to resolve the adjoint problem and obtain the values of the adjoint variables ( i j ) on load . We, then, compute the gradient(s) of the augmented functional using Equations (38) and (40) and obtain the search direction(s) using the conjugate gradient method. We use scalar step lengths (˛t and/or˛l ) to obtain and/or Á for the next inversion iteration and repeat the process until convergence.…”

“…This approach formally gives rise to an inverse source problem, which is similar to the inverse medium problems arising in exploration geophysics . Jeong et al used the inverse source approach to compute the optimal time signals driving the surface sources for a geostructure abstracted as a layered elastic solid in one or two spatial dimensions , whereas Karve et al developed an inverse source methodology to resolve not only the optimal source signals but also the optimal source locations. They conducted numerical experiments for two‐dimensional (2D), synthetically created geostructures and reported that the optimal source locations play a crucial role in maximizing wave energy delivery to the target formation.…”

Full-waveform inversion in three-dimensional PML-truncated elastic media

“…Due to the complexity of the inverse problem at hand, most techniques to date rely on simplifying assumptions, aiming at rendering a solution to the problem more tractable. These assumptions can be divided into five categories: a) assumptions regarding the dimensionality of the problem, whereby the original problem is reduced to a two-dimensional [17,20,22], or a one-dimensional problem [26]; b) assuming that the dominant portion of the wave energy on the ground surface is transported through Rayleigh waves, and thus, disregarding other wave types, such as compressional and shear waves, as is the case in the Spectral-Analysis-of-Surface-Waves (SASW) and its variants (MASW) [35]; c) inverting for only one parameter, as is done in [1,11,28,29], where inversion was attempted only for the shear wave velocity, assuming the compressional wave velocity (or an equivalent counterpart) is known; d) assumptions concerning the truncation boundaries, which are oftentimes, grossly simplified due to the complexity associated with the rigorous treatment of these boundaries [40]; and e) idealizing the soil body, which is a porous and lossy medium, as an elastic solid and neglecting its attenuative properties 1 [12]. Over the past decade, continued advances in both algorithms and computer architectures have allowed the gradual removal of the limitations of existing methodologies.…”