Journal of Energy Engineering

In the southern thrust belt (STB) of Junggar Basin, hydrocarbon resources are abundant at ultradeep depths. The genesis of highly mature oil and gas is complex, with considerable geological implications, because of the burial depth of these resources and multiphase tectonic evolution. The deep–ultradeep oil and gas reservoir accumulation processes and the contribution of Permian source rocks are still unclear in the STB. In this study, using the ultradeep reservoirs of the middle section of the STB (MSTB) as an example, systematic evaluations were conducted on the hydrocarbon geochemical characteristics of the area. Additionally, this study detailed the accumulation and evolution processes of the reservoir in the lower play of the MSTB using various comprehensive technical analyses, such as those for the geochemical characteristics of crude oil, the genesis and source of crude oil and gas, inclusion observations, homogenization temperature, quantitative particle fluorescence, and basin simulation. The integrated analysis results showed that the oil and gas from Well HT-1 in Huxi Anticline (HXA) in the lower play was characterized by mixed sources from Permian argillaceous source rock and Jurassic coal-bearing source rocks. The pristane/phytane ratio (Pr/Ph) and biomarkers of the crude oil indicated the presence of Permian source crude oil. The natural gas drying coefficient and the carbon isotope of methane conveyed a typical coal-related gas from the Lower–Middle Jurassic epoch. In addition, three types of hydrocarbon inclusions (yellow–green fluorescence, blue–white fluorescence, and gaseous hydrocarbons) were developed in the MSTB. Oil and gas accumulation periods included Early Cretaceous, Eocene, and Miocene. Finally, substantial deviations were found for accumulation periods from different anticlines in the study area, which were controlled by the ancient structural background and tectonic evolution. The early anticlines, formed by Yanshanian tectonic movement (YSTM), controlled the early hydrocarbon migration as well as reservoir formation, and the newer anticlines, formed by Himalayan tectonic movement (HMTM), controlled the redistribution of hydrocarbons from ancient reservoirs. The oil and gas reservoir formed in Qingshuihe Formation (${\mathrm{K}}_{1}q$) in HXA occurred during the Miocene. The ancient oil reservoirs to the south of HXA were damaged, and hydrocarbons were redistributed; the hydrocarbons migrated and accumulated in HXA and mixed with highly mature gas from Jurassic source rocks. The Permian hydrocarbons made a substantial contribution to the deep–ultradeep resources of MSTB and provided extremely rich hydrocarbon resources together with the Jurassic source rocks. Additionally, within MSTB, large anticlines were thoroughly developed in ultradeep strata, which provided superior trapping conditions for large-scale hydrocarbon accumulation.

This paper aims to improve the internal heat distribution and effective thermal management of a proton-exchange membrane fuel cell (PEMFC) while reducing its volume. A novel embedded liquid cooling channel was designed to achieve this, and a three-dimensional, multiphase numerical model of the PEMFC was established. Compared with the conventional straight-through channel, which features straight channels for both the anode and cooling runners, the embedded cooling channel demonstrates a lower temperature difference and pressure drop, reducing both by 17.5% and 71.9%, respectively. The embedded channel structure was studied based on indicators such as the index of uniform temperature distribution (IUT), average cooling channel walls heat flux, ${\mathrm{H}}_2$ mole fraction distribution, ${\mathrm{H}}_2$ flow channel pressure drop, and net power. The results show that increasing the contact length ($L$) between the anode plate and the anode diffusion layer is beneficial for the diffusion of anode gas, controlling fuel-cell temperature, and improving net power. Furthermore, it is recommended that the angle of the embedded channel be greater than 60°, and $L$ should be greater than $8/16$ of the PEMFC width. This study provides a new solution to the problem of PEMFC thermal management and valuable references for PEMFC engineering design.

As a recently developed flow field for the bipolar plate of a proton exchange membrane fuel cell, the wave flow channel has demonstrated several advantages in enhancing the gas supply within the channel. However, its unique shape poses challenges in effective drainage, as liquid water is prone to impinge on the side wall. In this study, to analyze water transmission performance of the wave channel, based on a coupled level set and volume of fluid method, a 3D two-phase water transport model of the wave channel was established, and the flow characteristics data of liquid water in the wave channel under different working conditions were calculated. The dynamic behavior of liquid water in the wave channel with initial forms of the liquid drop, liquid film, and liquid column were investigated, respectively. The results indicated that different initial forms of liquid water move through a wave channel all in the form of a membrane flow. When the initial form of liquid water resembles a liquid column, it exhibits the highest velocity of movement within a wave channel compared with the initial forms of liquid droplets and liquid film, assuming an equivalent volume. Further, the speed of liquid water movement increased with the volume of liquid water and the inlet gas velocity. Additionally, the contact angle of a gas diffusion layer surface exerts a substantial influence on water volume and slightly influences the move speed of liquid water.

The lithium metal anode represents an excellent choice of material for rechargeable batteries, while lithium dendrites growth has adverse effects on the manufacturing and performance of batteries because the lithium ions deposit unevenly on the electrode surface during the electrochemical process, which can lead to short circuits and safety issues within the battery. This work studied the morphology of lithium dendrites under two initial conditions: initial nuclei and smooth planar interface. By introducing the noise to the order parameter and concentration ratio, the model is able to simulate mossy dendrites, which is highly influenced by the nonuniformity of deposition and the charging conditions. Through the investigation of the fluctuations in lithium-ion concentration near the metal/electrolyte interface, it is found that with increased applied voltage, branches of the second order appeared orthogonal to the direction of growth. The simulation results reported in this work can shed light on the foundational principles of lithium dendritic growth and offer a regulation strategy for inhibition of lithium dendrite growth.

Depleted gas reservoirs type underground gas storage (depleted-UGS) are important facilities used to solve the imbalance of natural gas supply and demand. However, gas storage has high energy consumption, and depleted-UGS faults are widely distributed and divided into multiple disconnected blocks. Excessive pressure variation between reservoir blocks (RBs) will affect the stability of depleted-UGS operation. A multiobjective optimization model is established to solve the economic security scheduling problem of depleted-UGS. The model takes the pressure variation of RB and the energy consumption of the compressor as the optimization objectives, coupled with the constraints of reservoir seepage pressure drop and wellbore flow pressure drop. To find a high-performance algorithm to solve the depleted-UGS operation optimization problem, three multiobjective algorithms are tested, and reference vector guided evolutionary algorithm (RVEA) is chosen as the solution. We apply this model to a large depleted-UGS in China and use the RVEA to solve the optimal gas injection scheme for the depleted-UGS under two scenarios of low RB pressure variation and high RB pressure variation. The findings suggest that the optimized solution is more inclined to allocate more gas injection to the block with lower pressure and higher elastic yield. For the scenario where the pressure of the RBs is relatively balanced, the optimization scheme can reduce the energy consumption by 5.2% and the pressure difference by 79.3%. For scenarios with large pressure differences among RBs, the optimization scheme can reduce energy consumption by 17.4% and pressure difference by 41.3%.