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The Mahu Oilfield in Xinjiang, China, is the world's largest conglomerate oilfield, with a daily output of more than 8000 tons. In the fracturing of perforated horizontal wells, the breakdown pressure is high, resulting in difficulties in their treatment. Acid pretreatment has been applied to reduce the breakdown pressure in the field, but with poor performance. Few studies have been conducted on how acid pretreatment affects the breakdown pressure under perforation conditions in the Mahu conglomerate reservoir. Also, existing fracturing or acid pretreatment experiments cannot simulate perforation well. Therefore, a new method was developed to make perforations by hydro jetting the fracturing specimens (300 mm × 300 mm × 300 mm) first. It can achieve specified perforation parameters, including the perforation angle, position, and length. Subsequently, true triaxial hydraulic fracturing experiments were conducted on the conglomerate specimens obtained from the Mahu area. The effects of the acid pretreatment on the fracture initiation and breakdown pressure were investigated by injecting the perforation section of the conglomerate using various acid systems. The study results showed that the perforation made by the new apparatus was extremely close to the perforation on-site. The acid pretreatment effectively dissolved minerals and could decrease the breakdown pressure down to 7.7 MPa. A combination of 6%HF + 10%HCl was recommended for the acid pretreatment in the Mahu conglomerate reservoir. A total of 60 min acid–rock contact time is necessary for sufficient rock dissolution. The mechanism of the acid pretreatment to decrease the breakdown pressure is that the rock dissolution by the acid reduces the rock tensile strength and increases the permeability. The raised permeability increases the fluid pressure of the reservoir near the wellbore so as to reduce the breakdown pressure of the formation. The research results provide technical support for reducing construction difficulty and optimizing parameters in the Mahu Oilfield. [ABSTRACT FROM AUTHOR]

The goal of this article is to conduct a detailed study of China's forestry industry chain and determine the effect it has on the national economy. Based on the 2018 China Input–Output Table (153 departments) and other relevant data released by the National Bureau of Statistics, as well as the input–output method established by Wassily Leontief, this article conducts a comprehensive and detailed analysis of China's forest industry chain and its impact on the national economy. The results show that the backward industrial chain of China's forestry industry involves 105 industrial departments. China's forestry sector purchases the most products from the tertiary industry, accounting for 56.05% of all forestry purchases. The products of the tertiary industry have a significant impact on forestry. The forward industry chain of China's forestry involves 131 industrial sectors, with China's forestry selling the most products to the secondary industry, accounting for 93.47% of all forestry sales. The forestry sensitivity coefficient is 0.767 and the influence coefficient is 0.65. The secondary industry has a significant impact on the sales of forestry products. The impact of the forward industry chain is greater than that of the backward industry chain and the impact of forestry on the national economy is quite large. Suggestions about how to expand the planting area and production scale of domestic economic forests were put forward. An increase in the added value of exported forestry products, improved service quality of the tertiary industry to forestry, and improved quality and quantity of products provided by forestry to the secondary industry are necessary. [ABSTRACT FROM AUTHOR]

Aiming at the problem of explosion caused by leakage of flammable and explosive gas cylinder, a new type of safety protection device for gas bottle cabinet is designed to solve this problem. The design of this new type of gas bottle cabinet safety protection device is to use GSM voice, short message control technology, sensor technology, wifi technology, plc control technology and so on, to monitor the gas in the gas bottle cabinet in real time. Once the gas in the cylinder leaks and the concentration of the leakage gas reaches the set alarm concentration, the alarm will occur, and the exhaust fan will start to discharge the leakage gas and send an alarm message to the pre-set mobile phone at the same time.

Direct hydroxylation of benzene with a high selectivity and durability for phenol production is still a challenge. Herein, a reusable VxOy/AC(cit)-DBD catalyst was synthesized using a facile and environmentally benign method in which a mixture of citric acid, NH4VO3 and activated carbon (AC) was treated using dielectric barrier discharge (DBD) at room temperature and under an N2 atmosphere. Compared with VxOy/AC-DBD, which is prepared without citric acid, more vanadium species were exposed on the surface of VxOy/AC(cit)-DBD. The residues of citric acid formed by DBD treatment can stabilize the vanadium species on the surface of AC by restraining the leaching of vanadium from the catalyst during the reaction. Moreover, the addition of citric acid increased the ratio of V4+/V5+ and benzene adsorption on the catalyst surface, which are favorable for the hydroxylation of benzene. Additionally, the resulting vanadium particles are smaller (less than 10 nm) and amorphous owing to the inhibiting effect of citric acid residues on particle growth and the low temperature characteristics of DBD treatment. Under the optimized reaction conditions, VxOy/AC(cit)-DBD showed a good stability and recyclability in the hydroxylation of benzene and achieved a benzene conversion of 21.5% and phenol selectivity of 99.1%. [ABSTRACT FROM AUTHOR]