A Well Productivity Model for Multi-Layered Marine and Continental Transitional Reservoirs with Complex Fracture Networks

Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis,a model is developed to predict the related well production rate.This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales,as well as the flow characteristics in different types of thin layers(tight sandstone gas,shale gas,and coalbed gas).Moreover,a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir.A semi-analytical solution for the production rate is obtained using a matrix iteration method.A specific well is selected for fitting dynamic production data,and the calculation results show that the tight sandstone has the highest gas production per unit thickness compared with the other types of reservoirs.Moreover,desorption and diffusion of coalbed gas and shale gas can significantly contribute to gas production,and the daily production of these two gases decreases rapidly with decreasing reservoir pressure.Interestingly,the gas production from fractures exhibits an approximately U-shaped distribution,indicating the need to optimize the spacing between clusters during hydraulic fracturing to reduce the area of overlapping fracture control.The coal matrix water saturation significantly affects the coalbed gas production,with higher water saturation leading to lower production.

Seismic Design of Offshore Wind Turbine Withstands Great East Japan Earthquake and Tsunami

Japan＇s first open sea offshore wind farm, Kamisu offshore windfarm Phase l, was stricken by an earthquake of intensity 6 on the Japanese seismic scale and a five-meter-high tsunami during the Great East Japan Earthquake on March 11,2011. The wind farm resumed operation on March 14 after checks revealed no damage to the system, even though the wind farm was temporarily forced to stop due to the grid failure caused by the earthquake. Wind turbines require a precise seismic design especially in an earthquake-prone country such as Japan. Wind power Kamisu Phase 2 was built one year after the earthquake based on the experience of Kamisu Phase 1. This paper presents the seismic design of offshore wind turbines and the situation during the earthquake and tsunami.

Study on load performance of electric motor system used in hybrid electric vehicle

The performance of the power assist, global optimization solved by dynamic programming （DP） method, Chery and Insight control strategies are analyzed using the mild parallel hybrid electric vehicle （PHEV） model based on Insight structure. The influence of the four control strategies to the load power of the electric motor system used on parallel hybrid electric vehicle is studied. It is found that 80 percent of the motor load power points are under 1/5 of the electric peak power. The motor load power of the power assist control strategy is distributed in the widest range during generating operation, and the motor load power of the global optimization control strategy has the smallest one.

Laser irradiation of graphite foils as robust current collectors for high-mass loaded electrodes of supercapacitors

Conductive substrates with low cost,lightweight,and chemical stability have been highly recognized as alternative current collectors for energy storage devices.Graphite foil is promising to fulfill these requests,whereas the inert surface chemistry denies its possibility as the carrier with high-mass loading active species.Herein,we report a facile yet efficient laser-mediated strategy to fast regulate graphite foils for robustly loading active species.The smooth and hydrophobic graphite foil surface turned to be a rough,super-hydrophilic one containing oxygen-rich clusters after lasering.The reconstructed surface affords anchors for active species,such as nanostruetured MnO_(2),FeOOH,and Fe_(2)O_(3),with the highest loading mass of 20 mg·cm^(-2).The high-mass loading MnO_(2)electrode offers an areal capacitance of 3933 mF·cm^(-2)at 1 mA·cm^(-2).Then,the asymmetric supercapacitor,fabricated by MnO_(2)and Fe_(2)O_(3)deposited laser-irradiated graphite foils,exhibits improved performance with high energy density,large power capability,and long-term stability.The strategy suggests a reliable way to produce alternative current collectors for robust energy storage devices.

NaSICON:A promising solid electrolyte for solid-state sodium batteries

A surge of interest has been brought to all-solid-state batteries(ASSBs)as they show great prospects for enabling higher energy density and improved safety compared to conventional liquid batteries.Na Super Ionic CONductors(NaSICONs)proposed by Goodenough and Hong in 1976 are the most promising materials class for Nabased ASSBs owing to their excellent ion conductivity(>1mS cm−1),high thermal and chemical/electrochemical stability,as well as good chemical/electrochemical compatibility with electrode materials.The major challenge facing NaSICONtype electrolytes is the generally high interfacial resistance and thus sluggish charge transfer kinetics across the NaSICON/cathode interface.Great endeavors in the past few years have led to progress in the improvement of the ion-conducting property,and a dramatic decrease in the NaSICON/electrode interface resistance.Excellent cycling performance and rate capability have been achieved through interface engineering.In this review article,we summarize the state-of-theart findings for various derivatives of NaSICON structured solid electrolytes,with the aim of providing a deeper understanding of the underlying mechanism for the improvement of ion conductivity,and the intrinsic reasons for the enhanced interface charge transfer kinetics.These strategies can be readily extended to other solid electrolytes.We hope this review will inspire more work on NaSICONtype solid electrolytes and solid-state batteries.