A new model to predict the unsteady production of fractured horizontal wells

Based on the hydraulic fracture width gradually narrows along the fracture length, with consideration of the mutual influences of fracture, non-uniform inflow of fractures segments and variable mass flow in the fracture comprehensively, a spatial separation method and time separation method were used to establish fracture horizontal well’s dynamic coupling model of reservoir seepage and fracture flow. The results showed that the calculation productivity of variable width model is higher than that of the fixed width model, while the difference becomes smaller as time increase. Due to mutual interference of the fractures, the production of outer fracture is higher than that of the inner fracture. When the dimensionless fracture conductivity is 0.1, the middle segment of the fracture dominates the productivity and local peak emerges near the horizontal well. The flow in the fracture is with the ‘double U’ type distribution. As the dimensionless fracture conductivity increase, the fractures productivity mainly through the tips and the flow in the fractures with the ‘U’ type distribution. Using the established fracture width variable productivity prediction model, one can achieve the quantitative optimization of fracture shape

Morphology Control, Crystal Growth, and Growth Mechanism of Hierarchical Tellurium (Te) Microstructures

Understanding the factors that influence the growth and final shape of semiconductor tellurium microstructures is important for controlling their properties. However, relative to their single-crystalline nanostructures, the growth of complex structures that are ideally composed of nanostructures arranged in a particular way can be difficult to control. Here, we developed a facile solvothermal method and successfully completed the controlled synthesis of Te particles with distinctive morphologies, including flower-like, ball-flower, nestlike, and sheetlike structures. These structures, self-assembled from nanorods and nanosheets, are systematically studied by adjusting the reaction parameters, such as the amount of NaOH, the volume ratio of EG/EN, the amount of PVP, and the reaction time. Results reveal that the morphology of Te microstructures can be easily controlled by simply altering the reaction conditions and that NaOH plays a crucial role in the final morphology of Te products. The growth mechanisms and morphology control of hierarchical Te microstructures are proposed and discussed. This is the first time to report the preparation of complex hierarchical Te microstructures through a simple solution route. This simple solution approach to fabricate hierarchical Te superstructures with controllable morphologies can be easily scaled up and potentially extended to the hierarchical assembly of building blocks of other semiconductors

Synthesis of High Saturation Magnetization Superparamagnetic Fe₃O₄ Hollow Microspheres for Swift Chromium Removal

High saturation magnetization monodisperse Fe₃O₄ hollow microspheres (109.48 emu/g) with superparamagnetic property at room temperature are promptly synthesized by a one-step solvothermal process with the presence of sodium dodecylbenzenesulfonate as an additive. The as-synthesized products possess superparamagnetism, large cavity, high water solubility, and saturation magnetization at room temperature. In particular, these hollow microspheres exhibit both of a rather short separation time from industry wastewater and a high adsorption capacity about 180 mg/g at high Cr­(VI) concentrations, which is much better than those of reported magnetite solid nanoparticles. In addition, the X-ray photoelectron spectra (XPS) show that the uptake of Cr­(VI) into the spheres was mainly governed by a physicochemical process. The micelle-assisted Ostwald ripening process was proposed to explain the rapid formation of hollow structures by a series of control experiments. The as-manufactured products with the two advantages mentioned above serve as ideal candidates for environmental remediation materials