Methods for enhanced solvent dewaxing, among which the use of modifying additives is promising and inexpensive, are presented. Modifying additives belonging to various chemical classes are described. Polymer compositions based on poly(meth)acrylates with 10-30 C atoms in the alkyl radical are currently the most interesting modifying additives. Use of this type of compounds in solvent dewaxing significantly

With the development of oil pipeline transportation domains, the layout of regional oil pipeline transportation network is doubly influenced by regional development and its own evolution, more than that, it is a dynamic concept. In order to get more reasonable evaluation results, it is necessary to improve the traditional evaluation method by regarding the network layout behavior and regional space

Thermal oxidation stability is an important parameter for jet fuel practical application. In this work, in order to evaluate the influence of deoxygenation on fuel stability, samples of typical fuels (JP-10 and RP-3) were subjected to deoxygenation by nitrogen purge and then subjected to accelerated thermal oxidation (180°C, 200°C, and 220°C). The parameters of hydroperoxide number, total acid number

The paper discusses technical and economic aspects of technology used for transporting commercial heavy oil via trunk pipelines following its treatment with an ultrahigh frequency electromagnetic field (2450 MHz) as an alternative to preheating prior to pumping oils. According to a comparison of the life cycle costs (LCC) for these technologies, microwave treatment is preferable to “hot” pumping for

In this paper we have simulated the competitive adsorption of CO2, CH4, and N2 gases in deep coal seams by building a graphite supercell structure and discussed the impact of pressure, pore size, and multicomponent composition on CH4 desorption. The results show that the adsorption capacity of a single component gas changes is in the order of CO2 > CH4> N2. For the CH4/CO2 competitive adsorption, absorbed

Against the background of new urbanization, following the concept of “intensive, energy-saving, and ecological development,” the idea of interactive development of transportation and land use, minimum energy consumption, and environmental damage is put forward. Regional comprehensive transportation network will become the main trend of low-carbon ecological comprehensive transportation planning strategy

In this paper we established a comprehensive mathematical model to evaluate the conditions of safety and displacement system of the oil storage tank. The obtained theoretical solution was then analyzed by comparison with the actual storage data. The problem was addressed by step-by-step approach. Firstly, the cross-sectional method is used to establish a mathematical model for the relationship between

The crucial challenge associated with water-based drilling fluids for the extraction of shale gas is the inhibition of clay hydration in the drilling operation. The inhibition efficiency of shale inhibitors is determined by the content of particular groups in the molecule. In this report we studied the inhibition performance, inhibition mechanism, and environmental friendliness of three inhibitors

This paper is aimed at the problems of weak cement sheath, weak impact strength, low compressive strength, and low bonding quality in slim-hole cementing. The cement slurry system was improved by edding self-developing elastic emulsion combined with toughening fiber. The authors compared the influence of different toughening materials on the mechanical properties of cement stone. The evaluation results

The protective effectiveness of oil compositions in the presence of sulfur dioxide was studied. The moisture permeability of oil films and the corrosion rate of steels both protected and unprotected by oil films increase with increasing relative humidity and initial sulfur dioxide concentration in the atmosphere. The contribution of individual components to the protective effect of a film of synthetic

Oxidation of petroleum asphaltenes by potassium iodide (KI) is described. Oxidation under mild conditions is shown to be accompanied by iodination of the asphaltene aromatic core. The inducing reaction is the oxidation of sulfide sulfur atoms in the asphaltenes with reduction of iodate anion to molecular iodine; the coupled reaction, electrophilic substitution. X-ray photoelectron spectroscopy detected

Considering the production decline law of coal-bed methane wells, production decline can be divided into three types: exponential decline, hyperbolic decline, and harmonic decline. Research on the production decline law is very important for evaluation of CBM productivity. In this paper we have studied the law of production decline in Junlian region and established the production decline type for low

Oil pollution is a serious threat to wildlife and plants. Man-made disturbances can lead to complete or partial destruction of the soil cover. Creation of new and improvement of existing methods of soil cleaning and soil cover reclamation is an urgent problem. The article discusses promising reagents for cleaning and reclamation of oil-contaminated soils by bioremediation. The prospects of using the

Carbonate reservoirs in Asmari block of Missan oilfield are characterized by complex geological characteristics. Temporary plugging is commonly used for effective damage control caused by the working fluid when drilling in such complex multi-pressure reservoirs and for preventing leakage, blowout, and collapse in long open hole wells. In this paper a new temporary plugging drilling fluid formulation

To the article “Effect of Heavy Metals on Ecosystems” by A. F. Tumanyan, A. P. Seliverstova, and N. A. Zaitseva, Vol. 56, No. 3, pp. 390-394, July, 2020

The current research on the stability of the formation - cement sheath - casing combination is mainly based on the plane modelling, with established 3D model as just an example. There are no systematic studies of the three-dimensional model under triaxial ground stress when the influence of physical parameters on stability of the composite cementing interfaces is evaluated. By establishing a three-dimensional

In this paper a micro multi-phase flow equation is built based on the mechanism of a multi-phase fluid flow in porous media. The authors consider the impact of convection diffusion and the improved component mixing rule. In order to accurately evaluate the fluid flow in a low permeability reservoir, two models are established to simulate simple pore throat structure and complex pore throat structure

Biocomponents and bioadditives for automobile gasolines that are widely used in global practice are reviewed. The possibility of involving an alternative feedstock, i.e., biomass, into the motor-fuel production system is investigated.

A series of experiments was carried out to study the matching relationship between the pore structure in the reservoir and the molecular radius of gyration. The hydrodynamic radius Dh (molecular coil dimension) was tested by dynamic light scattering and was be used to characterize the crimping degree of polymer chains and molecular coil dimension. The storage modulus and loss modulus were studied through

The current study is devoted to the use of vegetable-oil fatty acids (FAs) as lubricity additives for modern diesel fuels with ultra-low sulfur contents. The effectiveness of liquid castor, linseed, coconut, and sunflower oils in the base components of diesel fuels for hydrotreating, hydrocracking, and hydroisomerization is comparatively evaluated. It is established that all investigated vegetable-oil

The use of degradable polymer materials as controlling additives to the working fluid during hydraulic fracturing is an area of interest in developing stimulation technologies. A temporary plugging agent with high compressive strength is used to block pre-fracturing or natural cracking and to initiate new fracture joints in order to increase the oil and gas passages, thereby realizing a stable production

Quantum-chemical modeling of the spatial and electronic structure of asphaltenes containing different numbers of electron-withdrawing substituents used the DFT/B3LYP-6-31G(d,p) method to predict the reactivity of petroleum asphaltenes upon their chemical modification. The change of torsion angle of the polycondensed aromatic asphaltene structure depending on the type of substituent was studied. The

The dependences of changes in the contaminant contents and base numbers of motor oil during refining are established. Finely disperse contaminant particles are enlarged if a mixture of ammonium hydroxide with 1% urea is added to working engine oil. Subsequent centrifugation with cleaning agents incorporated into the lubrication system allows almost all contaminants to be removed from the oil. The dependences

Due to the decline of formation pressure in the middle and late periods of low permeability reservoir development, the development effect deteriorates. Therefore, it is essential to restore and maintain reasonable formation pressure. Based on the two-phase fractional flow equation in low permeability porous media, we consider the flow characteristics in reservoirs with threshold pressure gradient and

The production technologies of environmentally friendly plasticizer oils such as TDAE, TRAE, MES, and NAP for the rubber and tire industries are considered. Their basic physicochemical properties and specific application examples are presented. The influence of the types of plasticizer oils on the performance properties of rubber products and tires is described.

In this paper a model is established for unstable seepage flow with polymer concentration and pressure diffusion coupling, considering the effects of polymer molecular diffusion, adsorption, and viscoelasticity of polymer solution in the formation. The factors are close to the actual seepage parameters of the injected reservoir. For the nonlinear adsorption, the combined variable and the analytical

In order to provide production safety and determine the optimal ventilation scheme in coal mining, the mines should be classified by their gas emission and mine security rank. In this paper the three models of mine classification, mine insecurity, and the optimal ventilation required by the mine are established and solved by MatLab and Lingo software. In answer to question 1, firstly, the daily absolute

Environmental pollution is one of the most serious problems in the sphere of ecology. Rapid industrialization, discovery and development of new oil fields, modern agricultural practices, and other types of anthropogenic activities contribute substantial amounts of toxic heavy metals to the environment. Heavy metals are some of the prominent substances that pollute soil, water and air. Pollution by

The reservoirs of volcanic rocks in the Junggar Basin of Xinjiang in China are abundant in reserves with potential for exploration and development. They have the characteristics of high heterogeneity and fracture development. The occurrence of bottom water coning is a serious problem during oilfield development, which leads to a rapid increase in the well water cut and greatly affects the reservoir

With the progress in oilfield development, low-quality resources are gradually developed, and related research is focused on condensate gas reservoirs. Complex physical properties of condensate gas reservoirs and complex components of condensate gas system make well testing and productivity analysis of condensate gas reservoir difficult, which is the main reason why there has been no breakthrough in

Gas processing is an independent dynamically developing industry whose role is growing constantly in connection with exploration and development of new gas and oil fields and increase of volume of recovered hydrocarbons subjected to processing. For further development of the industry it is essential to improve the existing technologies and equipment, which is impossible without analysis and solution

Field experience shows that horizontal well multi-stage fracturing technology can transform the volumetric pressure crack network in the formation and has been widely used in unconventional oil and gas resource exploitation. According to the requirements of horizontal well fracturing operations, this paper simulates the law of horizontal well fracturing in low-porosity and low-permeability sand-shale

At present, research on the influence of water on the physical properties of rocks is mostly focused on the macroscopic angle. Studies on nanoscale pore structure changes caused by water are few. Shale is characterized by good pore structure and high content of hydrophilic clay minerals susceptible to water. Based on this, in this paper the shale samples were obtained from underground layers 3000 m

With the country’s increasing requirements on environmental performance of drilling fluid treatment agents, which the traditional anti-collapse agent design has been unable to meet, research on environmentally-friendly anti-collapse agent molecular design is becoming increasingly important. This paper studies the effect of different types of groups on the anti-collapse characteristics and environmental

In this paper the method of mechanical modeling and formula derivation is applied to explains how earth rotation causes the apparent gravity action line to deviate from the ground plumb line. Analyzing the methods of the compass pendulum and the three-accelerometer and three-magnetometer survey, this paper demonstrates the principle that earth rotation causes well inclination error and azimuth error

Water is one of the causes of softening of soft rocks in deep strata. Water absorption in soft rock with high clay content may cause strength softening and deformation. In this paper, soft rock samples from three deep strata are investigated, and the stratigraphic characteristics such as stratum physical parameters, mineral composition, and pore structure are systematically analyzed. The characteristics

The early polymer flooding development technology has been applied to the Bohai Bay oilfield. However, about 50% of the residual crude oil remains in the formation after polymer flooding. The ways to improve the effect of polymer flooding needs to be further investigated. In this paper, we simulated the development effect of well pattern adjustment technology during polymer flooding through laboratory

The kinetics of carbon dioxide absorption from flue gases were studied. A mathematical modelwas developed to control the temperature of unsteady turbulent flows and the absorption with homogeneous combustion. The influence of various hydrodynamic and physiochemical factors on carbon dioxide absorption from flue gases using DEA as the absorbent was also determined. The developed mathematical model was

A method for producing a pelletized carbon adsorbent based on crude petroleum coke activated by potassium hydroxide and petroleum pitch as a binder is proposed. Granules were formed from mixtures prepared in various ratios and carbonized at ~800°C. It was found that the finished product with 30% added pitch retained 60-65% of the effective specific surface area of the used filler (activated coke).

A method for predicting the yield of unsaturated hydrocarbons during pyrolysis of individual alkane hydrocarbons and mixed hydrocarbons based on the conducted research and on literature data for pyrolysis of various hydrocarbon feedstocks was developed. The proposed method is universal for any type of feedstock and allows the maximum possible yield of target pyrolysis products to be pre-evaluated both

Transmission electron microscopy (TEM) was used to study the structure of particles of CO2-asphaltenes precipitated from a goudron vacuum residue sample in the gas anti-solvent (GAS) process using heptane, toluene, and their mixture (heptol) as diluents. It was shown that CO2-asphaltenes, despite lower aromaticity and polarity compared to C7-asphaltenes, have a similar irregular layered internal structure

Transmission electron microscopy (TEM) was used to study the structure of particles of CO2-asphaltenes precipitated from a goudron vacuum residue sample in the gas anti-solvent (GAS) process using heptane, toluene, and their mixture (heptol) as diluents. It was shown that CO2-asphaltenes, despite lower aromaticity and polarity compared to C7-asphaltenes, have a similar irregular layered internal structure

With the growing requirements on environmental protection in drilling fluid additives, the traditional anti-collapsing agents are unable to meet the demand. Therefore, improving the environmental protection performance of anti-collapse agents has drawn great attention from scientists. Organic amines are commonly used as anti-collapse agents due to their good anti-collapse properties. In this paper

The non-catalytic hydrovisbreaking of straight-run mazut residue in an upflow reactor filled with inert turbulizer-packing having a cellular structure and a free volume of about 65% was investigated. Feedstock conversion of 55.1 % was obtained under moderate conditions for such a process (temperature 450°C, hydrogen pressure 5 MPa). The conversion of the non-volatile residue, boiling above 540°C, amounted

The development characteristics of micro-fractures in the soft coal seam, which are often neglected in water-injection and exploitation of coalbed methane, are more complex compared to the hard coal seam. To investigate the influences of micro fractures on the water-injection effects in soft coal seams, our research took the dust control through water injection in a soft coal seam with soft roof and

An efficient optimization and design method has been proposed and developed for Enriched-gas Water-Alternating-Gas (EWAG) injection process. The proposed technique is able to quantitatively determine the sizes of the enriched-gas slug and water slug for each cycle of the water-alternating-gas (WAG) injection process, as well as the total number of injection cycles. Applying this method provides the

A smart and inexpensive method of enhancing the informative content for estimation of the performance properties level of new and modernized fuels and lubricants is proposed. It ensures the quantitative generalized (integral) expression and comparison of the potential propensity of fuels and lubricants for transformations coming out in different ways depending on the operation conditions and the engineering

Acidizing is one of the most economical and effective methods for ensuring the continuous and stable production of an oilfield and improving oil recovery. Diverting acids are more and more widely used in oilfields. However, it is difficult to accurately determine such parameters as acid discharge, concentration, and acid-rock reaction duration before construction, which may result in poor acidizing

The method of alpha-olefin oligomerization employing a heterogeneous catalyst for production of base oils used in motor and transmission oils manufacturing is considered, which has better performance and is eco-friendlier than methods employing homogeneous highly corrosive catalysts like BF3, or AlCl3. New methods and technology for online analysis of the reaction products and process flows have been

The scientific and reasonable layout of jack-up drilling platform can improve the efficiency and safety of drilling platform operation. Through the application of analytic hierarchy process (AHP) and the establishment of comprehensive evaluation and analysis model, this paper analyzes the commonly used drilling platform layout scheme and optimizes the scheme to meet operational requirements and to

As one of the most advanced international drilling technologies at present, rotary steering has been extensively applied to large-displacement, long-distance horizontal, and complex structural wells with numerous advantages, such as strong steering deflecting capacity and good borehole quality. Push-the-bit rotary steering is nowadays commercially applied on a large scale. In the bottom hole assembly

Dispersion of oil-tank sludge using compositions of cationic, anionic, and nonionic surfactants followed by isolation of synthetic oil is a processing method with several disadvantages such as residual S-containing compounds and toxic spent solutions. The present work proposes the use of polycomplexants (sodium salts of iminodiacetate derivatives of fatty-acid triglycerides and mucosaccharides) as

Sand control measures in horizontal wells are mainly based on screens. Horizontal wells have a certain length of horizontal displacement and the kick-off section with large curvature. Therefore, it is necessary to evaluate the safety of the screen downhole run before it runs into the hole, in order to minimize the running risk. In this paper, the pipe string is divided into sections, and the equivalent

A study was carried out on aspects of phenomena on the interfacial boundary of acids and hydrocarbon systems of different complexity. These phenomena were evaluated relative to the interfacial tension measured by the pendant drop method. We discovered peculiarities of the interaction of hydrochloric and sulfamic acids with individual hydrocarbons as well as complex hydrocarbon systems. The complex

This article presents a brief comparative overview of the methods for controlling phase formation in oil disperse systems, of which those that record the initial phase-forming stages and are used for preventing undesirable complications in oil preparation, production, and transportation processes are investigated. Switch from static to dynamic methods is of special importance for creating steady multiphase

For oil wells with high sand content, traditional oil well pumps easily get stuck. Increasing the gap between the plunger and the pump cylinder can effectively prevent the sticking, but the gap leakage also increases, resulting in a decrease in the volumetric efficiency of the pump. As shown in this paper, when a rectangular groove is formed in the plunger of the oil well pump, it can significantly

Casing drilling has been recognized as a practical method to reduce drilling costs and avoid particular drill string problems that often occur in conventional drilling processes. To gain a better understanding of the whirling motion of rotating casing, the energy method was adopted to calculate the critical whirling speeds of casing for both pinned-pinned and fixed-fixed types of support. The calculated

The non-interference uniform speed rope drilling coring device is a tool for investigating samples of submarine underground leakage hydrate rock formations. In the process of coring, the penetration resistance of the shoe is large, and the rock stratum is disturbed, which results in disturbance of the rock sample's original state. In order to solve this problem, the standard core diameter is ∅72 mm

In recent years, the exploration and development of shale oil and gas reservoirs has become a hot topic in various countries around the world. The mechanical properties of shale are an important basis for evaluating the mining effect. Previous studies have shown that shale swells with water, which greatly effects its mechanical properties. Based on the analysis of shale composition, a clay mineral

The physicochemical properties of nine summer base diesel fuels were compared. The influence of the group hydrocarbon composition on the low-temperature properties was examined using two fuels with similar physicochemical properties as examples. The physicochemical characteristics of the fuel were shown not to be definitive, rather, its detailed group chemical composition reflecting the molecular-mass