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Summary: A new method of reactive power control by photovoltaic and hydrogen is presented in this study. Photovoltaic has been employed for harvesting the hydrogen which is based on considering the weather conditions. The proposed system includes a combination of photovoltaic, hydrogen, and fuel cell along with a DG to connect to the grid and to improve the supply power quality. The main contribution of this paper is to direct an improved metaheuristic algorithm, called improved coyote optimization (CO) algorithm for achieving a proper DG placement. The improved version of the CO algorithm has benefitted from a spiral policy that is derived from Whale optimization algorithm. This process makes better control for the social behavior of the coyotes. Reactive power optimization (RPO) has been established after the size selection objective function. Big data technology is also used for improving the historical solution matching‐based RPO appliance. Cosine distance is used for measurement purposes of the historical solution matching‐based similarity technique during the computation time of conventional RPO and PVH‐FC features. As a result of using the suggested CO, the costs for electricity and losses are reduced by around 86.6% and 26.9%, respectively. Additionally, realized profits showed that applying the suggested strategy reduced the overall cost from 9.315e6 to 4.435e6 units. After optimization, the network loss and power are finally reduced to 1325 Kvar and 1371 kW, respectively. The results show that the suggested RPO technique has higher speed of calculation in comparison with some latest algorithms. Achievements also show that the suggested method provides a proper and optimal solution for RPO. [ABSTRACT FROM AUTHOR]

The multi-stage and multi-cluster fracturing of horizontal wells is mostly used for the development of the tight oil' the fracture shape and extension are difficult to be precisely controlled, and the fracturing fluid contamination seriously jeopardizes the surrounding water bodies. To address the above problems and to utilize tight oil reservoirs more safely and efficiently, the clustered borehole type horizontal multilateral well pattern was proposed for oil production, and an oil drainage model based on the oil-water phase seepage distribution mechanism was established by simulation software. Through the capacity prediction, the fishbone-shaped horizontal multilateral well with optimal branching angle and location arrangement was selected, and this well pattern was applied to the clustered borehole type horizontal multilateral well and its production and injection performance was studied. The study shows that the clustered borehole well pattern has wider oil drainage area and faster water breakthrough. The clustered borehole well pattern has excellent production and injection performance, shorter construction period, higher safety and efficiency. After 10 a of depletion production under the same conditions, the clustered borehole well pattern increases production by about 11. 12% compared with the fishbone-shaped horizontal multilateral well; the average daily oil production of the LD- 1 platform Chang 71 well group increases by 13. 21% after 4 a of simulated production using the clustered borehole well pattern; neighboring wells were extracted under simulated injection and extraction conditions for 20 a, the clustered borehole well pattern is used as the injection well, and the cumulative oil production of a single well increases by about 23. 7% compared with that of the fishbone-shaped horizontal multilateral well. The study can provide technical references for the structural optimization of the clustered borehole well pattern and the efficient exploitation of tight reservoirs. [ABSTRACT FROM AUTHOR]

The casing leakage phenomenon seriously affects the safety and economic problems of oil and gas production and transportation. In this paper, the numerical simulation study of the casing's micro-leakage flow field and acoustic field is carried out by taking the oil and gas well casing as the research object. The CFD numerical model of the casing micro-leakage is established, and the influence of the size of the leakage hole, the shape of the leakage hole, and the pressure difference between the inside and outside the casing on the microleakage flow field is analyzed. An acoustic-vibroacoustic coupling calculation model based on Fluent and LMS Virtual LAB is established, and the sound pressure value and distribution at different frequencies are calculated. The results show that the flow rate of the leakage hole increases with the pressure difference between the inside and the outside leakage hole and the area of the leakage hole. Moreover, the flow rate of the circular leakage hole is higher for the same leakage hole area. The simulation model based on the equivalent sound source can be used to calculate and analyze the sound field in the tubing. By sound field computation based on the near-field equivalent sound source, when the frequency is 32,000 Hz, the amplitude of sound pressure is maximum. In addition, the sound pressure is greatly reduced once the sound wave passes through the tubing pipeline. Lastly, the sound pressure is higher at the position facing the leakage hole in the tubing, making detecting the leakage sound field signal easier. The results can provide a reference for further research on oil casing microleakage detection technology. [ABSTRACT FROM AUTHOR]

In the early construction of cavern leaching in salt cavern gas storages, the inner leaching tubing is often blocked, frequently leading to the bending deformation phenomenon of the leaching strings, which can result in out-of-control cavity shapes. It is difficult to monitor the stress, vibration, and morphological changes of the inner tube during the construction of a cavity. There are few research results in this field at home and abroad, and they are limited only to preliminary explorations of the mechanism or summaries and speculation of the field operation. In this paper, an experimental device for testing the dynamic characteristics of salt cavern leaching strings is developed based on the similarity principle. The device is used to simulate two types of operation processes, i.e., the direct and reverse circulation leaching processes. The experimental data are processed using the modal analysis method to obtain the vibration characteristic parameters of the inner leaching tubing in the circulation process with identical flow rates inside the tubing and the annular region. The following main conclusions can be drawn: The circulation mode has no significant effect on the vibration frequency of cavern leaching strings. The deformation characteristics of cavern leaching strings during direct and reverse circulation are identical, featuring maximum deformation at the bottom and minimum deformation in the middle. The maximum deformation of cavern leaching strings during reverse circulation is about 1.5 times that during direct circulation. Through an experimental investigation and analysis, the effects of the water injection rate and the cavern leaching method on the vibration frequency and bending deformation of cavern leaching strings was determined, providing a reference for further solving the bending problem of cavern leaching strings in combination with engineering practice. [ABSTRACT FROM AUTHOR]