Simulation of Pressure- and Temperature-Dependent Fracturing Fluid Loss in Multi-Porosity Multi-Permeability Formations

In this paper, the multi-porosity multi-permeability porothermoelastic theory is used to derive the analytical solution to calculate the pressure- and temperature-dependent fracturing fluid loss. A triple-porosity triple-permeability source rock formation is selected as an example to illustrate the model. The effects of fracturing fluid temperature and natural fractures on the fluid loss rate are systematically illustrated. The model successfully accounts for the varying leak-off rates in the multi-permeability channels through the hydraulic fracture faces. Furthermore, thermal diffusion near the hydraulic fracture faces contributes to a variation of pore pressure whose gradient at hydraulic fracture faces directly controls the fracturing fluid leak-off rate. The model shows that thermal effects bring almost 27% variation in the leak-off rate. Comparison study indicates that the single porosity model without considering multi-permeability systems or thermal effects significantly underestimates the rate of fracturing fluid loss and predicts nearly 84% and 87% lower leak-off rate, compared to the dual-porosity dual-permeability and triple-porosity triple-permeability models, respectively. Two case studies using published laboratory measurements on naturally fractured Blue Ohio sandstone samples are conducted to show the performances of the model. It is shown that the model presented in this paper well captures the total leak-off volume during the pressure-dependent fluid loss measured from laboratory tests. Matching the analytical solution to the laboratory data also allows rocks’ double permeabilities to be estimated.

Problems of Commodity Nomenclatures Implementation in the International Trade on the Example of Chapter 56 “Nonwovens” of the EAEU Commodity Nomenclature of Foreign Eco nomic Activity

The article examines the problems of using the Commodity Nomenclature of Foreign Economic Activity. The following problems are highlighted: the lag of the Harmonized Commodity Description and Coding System from the development of technologies; disagreement of countries with the decisions of the Harmonized System Committee; mistakes in texts; difficulties with the implementation of the classification decisions of the Federal Customs Service and Eurasian Economic Commission. Discrepancies in classification lead to distortion of mirror statistics of foreign trade and make it possible to identify “risk” and “cover” goods. The purpose of the work was to compare the imports by the Russian Federation nonwovens of chapter 56 from three countries — the main exporters at the level of commodity headings and subheadings. The hypothesis was tested: since chapter 56 is not the leading one in the volume of imports, there will be no significant discrepancies in the mirror statistics. Research method was comparison of data on Russian imports from a trading partner country and corresponding data on exports of a trading partner country to Russia. Data source is Trade Map of the International Trade Center. Headings 5602 (felt) and 5603 (nonwovens) were considered, which include goods that are similar in structure and properties, as well as heading 5607 — twine, cordage, ropes and cables. These goods are imported from both European and Asian countries. However, only when importing from the Asian direction — from China — discrepancies in the mirror statistics were found. It is shown that goods of “risk” (heading 5602) were imported into Russia from China in 9 times less than exported from China, and goods of “cover” (heading 5603) were imported from China by 5% more, than exported by China. The subheading of twine, cordage, ropes and cables made of synthetic fibers (570650) also represents risk goods, imports of which are 3 times less than exports from China. There are several cover headings that include similar goods with a lower duty rate. Comparison of duties showed that the main reason for classification errors leading to distortion of mirror statistics is the deliberately wrong choice of the code in the presence of close alternatives, which allows to reduce the customs payment. The hypothesis that group 56 will not show significant discrepancies in mirror statistics has not been confirmed.

The Usage of Economic Position in Understanding Indonesia’s Economy and the Pandemic Effects

Before the global pandemic hit the economy in 2020, Indonesia had experienced two contractions in 1963 and 1998. These contractions come with hyperinflation, while the recent contraction of 2020 has not. This paper attempts to analyse the C-19 pandemic 2020 effects on the economy, which generates contraction but has a low inflation rate. On the opposite, the Asian Financial Crises (AFC) of 1998 caused negative economic growth andskyrocketing inflation. This paper applied descriptive data analysis and showed that the AFC affected the aggregate supply while the pandemic impacted the aggregate demand. This paper offers the usage of the proportion of inflation rate and economic growth rate and the annual sectoral growth rate comparison to describe Indonesia’s economic position and the pandemic effects.

Pumping Power & Flow rate comparison of Double Pipe Corrugated Heat Exchanger (DPCHE) against Smooth Double Pipe Heat Exchanger (SPHE)

Heat Exchangers are indispensable in the development of various industrial and daily use systems. However, the effectiveness of the heat exchangers depends on the geometry, working fluids, type, and arrangement of the flow-through heat exchangers. A lot of experimentalists are working around the globe to find out the methods on how to enhance the productivity of different fluids with varied properties.