Search

Three-dimensional geological modeling is essential for simulating natural gas hydrate (NGH) productivity and formulating development strategies. Current approaches primarily concentrate on the single-phase modeling of either hydrate or free gas layers. However, an increasing number of instances suggest that the three-phase coexistence zone, which includes hydrate, gas, and water, is common and has become a focal point of international research, as this type of reservoir may present the most viable opportunities for exploitation. At present, there exists a significant gap in the research regarding modeling techniques for such reservoirs. This study undertakes a comprehensive modeling investigation of the three-phase zone reservoir situated in the sand layer of the Qiongdongnan Basin. By employing deterministic complex geological modeling techniques and integrating existing seismic and logging data, we have developed a three-phase coexistence zone model that precisely characterizes the interactions between geological structures and utilizes them as auxiliary constraints. This approach effectively mitigates the potential impact of complex geological conditions on model accuracy. Through a comprehensive analysis of 105 seismic profiles, we enhanced the model's accuracy, resulting in the creation of a three-phase coexistence zone model comprising 350,000 grids. A comparison between the modeling results and well data indicates a relatively small error margin, offering valuable insights for future development efforts. Furthermore, this method serves as a reference for modeling hydrates in marine environments characterized by three-phase coexistence on a global scale. [ABSTRACT FROM AUTHOR]

Motivated by the recent experimental study on hydrogen storage in MXene multilayers [Liu et al., Nat. Nanotechnol. 16, 331 (2021)], for the first time we propose a workflow to computationally screen 23 857 compounds of MXene to explore the general relation between the activated H2 bond length and adsorption distance. By using density functional theory we generate a dataset to investigate the adsorption geometries of hydrogen on MXenes, based on which we train physics-informed atomistic line graph neural networks (ALIGNNs) to predict adsorption parameters. To fit the results, we further derived a formula that quantitatively reproduces the dependence of H2 bond length on the adsorption distance from MXenes within the framework of Pauling's resonating valence bond theory, revealing the impact of transition metal's ligancy and valence on activating dihydrogen in H2 storage. [ABSTRACT FROM AUTHOR]

The lattice thermal conductivity of carbon materials is particularly interesting because it can vary within a range spanning five orders of magnitude depending on the atomic configuration. Herein, we systematically study the lattice thermal conductivity and phonon transport properties of pentadiamond, a new three-dimensional carbon allotrope consisting of pentagonal carbon rings. Based on first-principles calculations and an iterative solution to the linearized Boltzmann transport equation, the intrinsic lattice thermal conductivity (kl) is found to be 490.88 W/mK at room temperature, much lower than 2664.93 W/mK of diamond. A detailed analysis of both harmonic and anharmonic properties reveals that the low kl of pentadiamond essentially originates from its large phonon phase space, short phonon relaxation time resulting from strong overlap between the acoustic and low-lying optical phonon branches, and the low phonon group velocity. The distinct thermal transport behavior exhibited in pentadiamond further shows the diversity and complexity in lattice thermal conductivity of carbon allotropes. [ABSTRACT FROM AUTHOR]

Bismuth compounds have been playing an important role in thermoelectric (TE) applications. To match the high figure of merit (ZT) of n-type Bi-based TE materials for constructing effective TE devices, searching for p-type Bi-based TE materials with high ZT is highly desirable. Inspired by the successful exfoliation of BiOBr atomic layers [Wu et al., Angew. Chem. 130(28), 8855 (2018)], we systematically study the TE properties of single-layer BiOBr by using density functional theory and semiclassical Boltzmann transport theory, and we find that the p-type doped single-layer BiOBr exhibits a peak ZT value of 1.84 at 800 K, exceeding the highest value ever achieved among bulk p-type Bi-based TE materials (ZT = 1.4) [Poudel et al., Science 320(5876), 634 (2008)]. [ABSTRACT FROM AUTHOR]