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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]

A large amount of cyanide-containing wastewater is discharged during electrode material synthesis. Among them, cyanides will form metal–cyanide complex ions which possess high stability, making it challenging to separate them from these wastewaters. Therefore, it is imperative to understand the complexation mechanism of cyanide ions and heavy metal ions from wastewater in order to obtain a deep insight into the process of cyanide removal. This study employs Density Functional Theory (DFT) calculations to reveal the complexation mechanism of metal–cyanide complex ions formed by the interaction of Cu+ and CN− in copper cyanide systems and its transformation patterns. Quantum chemical calculations show that the precipitation properties of Cu(CN)43− can assist in the removal of CN−. Therefore, transferring other metal–cyanide complex ions to Cu(CN)43− can achieve deep removal. OLI studio 11.0 analyzed the optimal process parameters of Cu(CN)43− under different conditions and determined the optimal process parameters of the removal depth of CN−. This work has the potential to contribute to the future preparation of related materials such as CN− removal adsorbents and catalysts and provide theoretical foundations for the development of more efficient, stable, and environmentally friendly next-generation energy storage electrode materials. [ABSTRACT FROM AUTHOR]

The development of the Mahu tight reservoir has adopted horizontal wells with staged fracturing. In the fracturing, there is a problem of a high fracturing pressure. Acid treatment is often used to lower the fracturing pressure on site. At present, the impact of this acid treatment on the physical parameters of the rocks of the reservoir in the Mahu region has not been systematically studied. Aiming to solve this problem, this paper conducted an experimental study on how acid dissolution affects the physical properties of the Mahu conglomerate, including its porosity, permeability, triaxial rock mechanical parameters, tensile strength, and mineral composition. First, the experimental scheme was designed. Next, a series of experiments were conducted. Finally, the experiment results were analyzed comparatively before and after acidizing. The acid composition, concentration, and contact time were the main factors for the analysis, based on which the acid system and related parameters were recommended. This study showed that the Mahu conglomerate exhibited brittle plasticity characteristics under stress. The carbonate content in this region was low, while the feldspar content was high, so it was necessary to use mud acid to effectively dissolve feldspar, clay, and other silicates. After acidizing, the porosity was 200% of the original value. The permeability increased by up to 14 times. The tensile strength decreased significantly by up to 84%. The value of Young's modulus of the rock decreased by up to 63.6%. The value of Poisson's ratio was reduced by up to 40.7%. A combination of 6% HF + 15% HCl is recommended, with an effective acid treatment time of over 60 min for the Mahu conglomerate. Acidizing could significantly change the mechanical properties and permeability of the rock of the Mahu conglomerate reservoir, thus effectively reducing the formation fracturing pressure. This research provides technical support for Mahu acid dipping in horizontal well fracturing. [ABSTRACT FROM AUTHOR]

The solubility of hydrogen sulfide in different mole ratios of ferric chloride and 1-butyl-3-methylimidazolium chloride ionic liquid (rFeCl3/[bmim]Cl, r = 0.6, 0.8, 1.0, 1.2, 1.4) at temperatures of 303.15 to 348.15 K and pressures of 100 to 1000 kPa was determined. The total solubility increased with the increase of pressure and the decrease of temperature. The solubility data were fitted using the reaction equilibrium thermodynamic model (RETM). The mean relative error between the predicted value and the measured value was less than 4%. Henry's coefficient and the equilibrium constant of chemical reaction at each temperature were calculated. Henry's coefficient first decreased and then increased with the increase of mole ratio, and increased with the increase of temperature. The equilibrium constant of the chemical reaction followed the same law as Henry's coefficient. The chemical solubility was related to both Henry's coefficient and the chemical equilibrium constant. H2S had the highest chemical solubility in FeCl3/[bmim]Cl at a mole ratio of 0.6 and a temperature of 333.15 K. The chemical solubility increased with the increase of pressure. [ABSTRACT FROM AUTHOR]