Analysis of the global energy market development allows to conclude that natural gas is becoming the main energy resource in the structure of world energy consumption in the nearest future. At the same time the statistical data show that there is a significant reduction in the hydrocarbon reserves over hydrocarbon production, and the time is right to concern about the development of renewable energy projects. The authors analyzed the indicators of the availability of the hydrocarbon reserves over hydrocarbon production. Calculations show that the values of the reserves-to-production ratio are estimated as 90 years for organic fuel and as 54 years for hydrocarbon raw materials in 2017. The projects of "hybrid" energy that combine the traditional production of hydrocarbons with the development of renewable energy projects will be the most needed in the medium term. Some proposals on the subject of this article are based on the collaborate research of Gubkin University and Royal Institute of Technology (Stockholm, Sweden). Currently the autonomous combined power installation on renewable energy sources with energy storage system application is very attractive. The analysis shows that the most objects of the Russian oil and gas complex are located in areas that are promising for the practical use of renewable energy such as solar and wind energy. The results of modeling show that the autonomous combined power installation on renewable energy sources with energy storage system application is one of the possible ways to increase the energy efficiency and reliability of remote oil and gas facilities energy supply.

Diversification of gas supply via the liberalization of the gas trade, the discovery of new fossil gas sources, and the increasing use of renewable gases, are favoring pronounced and more frequent fluctuations in gas quality. The knowledge of gas quality is crucial for custody transfer, and safe, efficient and low-emission operation of gas-driven processes. The onsite measurement of gas quality by the operators of gas production facilities, gas grids, gas storage and gas utilization facilities is an emerging requirement. This paper describes several different approaches for determining gas quality by direct, indirect and inferential methods based on the physicochemical properties of gas. Special emphasis is devoted to a discussion on the miniaturization of gas quality sensors and the incorporation of hydrogen detection and measurement into these sensors, due to potential hydrogen admixture to natural gas. In addition, an overview and analysis of the regulatory and normative requirements for gas quality measurements are presented. Furthermore, an overview of gas quality measurement devices and sensors, recent developments as well as challenges and benefits associated with gas quality measurement instrumentation, are provided.

There is widespread evidence that petroleum originates from biological processes(1-3). Whether hydrocarbons can also be produced from abiogenic precursor molecules under the high-pressure, high-temperature conditions characteristic of the upper mantle remains an open question. It has been proposed that hydrocarbons generated in the upper mantle could be transported through deep faults to shallower regions in the Earth's crust, and contribute to petroleum reserves(4,5). Here we use in situ Raman spectroscopy in laser-heated diamond anvil cells to monitor the chemical reactivity of methane and ethane under upper-mantle conditions. We show that when methane is exposed to pressures higher than 2 GPa, and to temperatures in the range of 1,000-1,500 K, it partially reacts to form saturated hydrocarbons containing 2-4 carbons (ethane, propane and butane) and molecular hydrogen and graphite. Conversely, exposure of ethane to similar conditions results in the production of methane, suggesting that the synthesis of saturated hydrocarbons is reversible. Our results support the suggestion that hydrocarbons heavier than methane can be produced by abiogenic processes in the upper mantle.

What will happen when methane is at a temperature of 1500 K? On the first glance the answer seems to be obvious methane will decompose into hydrogen and one of the forms of carbon. Yes. However is does not do so at very high pressure, when novel reaction pathways become possible. The latest experimental results and theoretical calculations show that methane and heavier hydrocarbons are, remarkably enough, stable under extreme pressures and temperatures. Even more, experiments confirm the possibility of abiogenic synthesis of natural gas at 5.0 GPa and 1500 K. The review summarizes published results of theoretical and experimental investigations of possible pathways under the conditions of pressure and temperature that prevail in the Earth's upper mantle for the formation of (1) particular species of hydrocarbon molecules, and of (2) complex hydrocarbon systems. The results raise fundamental questions on the genesis of hydrocarbons.

World experience shows that important factor in the calculations for natural gas consumption between suppliers and consumers is not only the volume of natural gas, but the quality indicators. With gas market liberalization, gas properties are expected to vary more frequently and strongly (composition, heating value etc.). Quality of natural gas is currently a topical issue, considering the steady increase of gas consumption in the world in recent decades. Existent chromatographs and calorimeters are very accurate in gas quality determination, but general expenditure and maintenance costs are still considerable. Market demands alternative lower cost methods of natural gas quality determination for transparent energy billing and technological process control. Investigation results indicate that heating value (HV) is a nonlinear function of such parameters as sound velocity in gas, N2 and CO 2 concentration. Those parameters show strong correlation with natural gas properties of interest (HV, density, Wobbe index), during analysis conducted on natural gas sample database. For solving nonlinear multivariable approximation task of HV determination, artificial neural networks were used. Proposed approach allowed excluding N2 concentration from input parameters with maintenance of sufficient accuracy of HV determination equal to 3.7% (with consideration of N2 concentration - 2.4%) on sample database. For validating of received results corresponding experimental investigation was conducted with reference analysis of physical and chemical parameters of natural gas samples by gas chromatography and followed superior HV calculation according to ISO 6976:1995. Developed experimental setup consist of measuring chamber with ultrasonic transducer, reflector, pressure, temperature and humidity sensors, ultrasonic inspection equipment for sound velocity measurements and CO2 concentration sensor with relevant instrument. The experimental setup allows measurement of sound velocity at 1MHz frequency and CO2 concentration in natural gas sample along with parameters control (temperature, humidity, pressure). The HV calculation algorithm was based on specially designed and trained artificial neural networks. Experimental investigation of proposed approach was conducted on 40 real samples of locally distributed natural gas. Obtained results, in comparison to reference values, showed absolute error in Lower HV (net calorific value) determination equal 166 kJ/m3, while relative error was equal 4.66%. Developed technology allows construction of autonomous instrument for instant natural gas quality determination, which can be combined with volume meters in order to provide transparent energy flow measurement and billing for gas consumers. Additionally it can be used for gas sensitive technological process control.

Raman spectroscopy studies on n and i-butane were performed at pressures of up to 40 GPa at ambient temperatures using the DAC technique. Normal butane undergoes two phase transitions at 1.9(5) GPa and 2.9(5) GPa and isobutane at 2.7(5) GPa and 3.5(5) GPa. These phase transitions were identified based on observations of the splitting Raman modes and the appearance or disappearance of particular Raman peaks. Our results demonstrate the complex, high-pressure behavior of butane isomers.

Raman and IR spectroscopy studies on propane were performed at pressures of up to 40 GPa at ambient temperatures using the diamond anvil cell technique. Propane undergoes three phase transitions at 6.4(5), 14.5(5), and 26.5(5) GPa in Raman spectroscopy and at 7.0(5), 14.0(5), and 27.0(5) GPa in IR spectroscopy. The phase transitions were identified using the Raman and IR splitting modes and the appearance or disappearance of peaks, which clearly corresponded to the changes in the frequencies of the modes as the pressure changed. Our results demonstrate the complex high-pressure behavior of solid propane.

The reciprocal influence of crystallization and vitrification processes in complex hydrocarbon systems was analyzed. These systems consist of a high-molecular-weight amorphous matrix in which easily crystallized components of different molecular weight and composition are dissolved. It was shown that the invariability of the position of the glass transition line indicates that the hydrocarbon matrix of the system does not change when waxes, asphaltenes, and resins are extracted. The presence and composition of the crystalline clusters in the hydrocarbon matrix do not affect the glass transition process. Calorimetric studies of the model system at atmospheric pressure in the 130-370 K temperature range were conducted. The measurements confirmed the existence of the crystallization process in a narrow temperature range and the absence of the glass transition process. The results also show that the appearance of crystallization does not affect the glass transition process.

The thermal conductivity of five samples of crude oil and one sample of gas condensate was measured by the transient hot-wire technique. The measurements were made along isotherms ( 245, 250, 273, 295, 320, 336, and 373 K) in the pressure range from atmospheric pressure up to 1000 MPa and along isobars ( at 0.1, 100, 200, 300, 400, 500, and 1000 MPa) in the temperature range 245-450 K. It was observed that the thermal conductivity of the samples investigated strongly depends on the pressure and rises with increasing pressure for all the temperatures. At a certain pressure, the temperature coefficient of thermal conductivity reverses from negative to positive. The pressure at which this reversal was observed varied in the range of 300-380 MPa.

A theory of abiotic deep petroleum origin explains that hydrocarbon compounds are generated in the upper mantle and migrate through the deep faults into the Earth's crust. There they form oil and gas deposits in any kind of rock in any kind of the structural position. Until recently one of the main obstacles for further development of this theory has been the lack of reliable and reproducible experimental results confirming the possibility of the spontaneous synthesis of complex hydrocarbon systems at high pressure and temperature. Our experimental results demonstrate that abiotic synthesis of hydrocarbons under mantle conditions is a real chemical process. Different paths of hydrocarbon synthesis under mantle conditions are discussed. Obtained experimental results place the theory of the abiotic deep petroleum origin in the mainstream of modern experimental physics and physical chemistry.

The theory of the abyssal abiogenic origin of petroleum is a significant part of the modern scientific theories dealing with the formation of hydrocarbons. These theories include the identification of natural hydrocarbon systems, the physical processes leading to their terrestrial concentration, and the dynamic processes controlling the migration of that material into geological reservoirs of petroleum. The theory of the abyssal abiogenic origin of petroleum recognizes that natural gas and petroleum are primordial materials of deep origin which have migrated into the Earth's crust. Experimental results and geological investigations presented in this article convincingly confirm the main postulates of the theory and allow us to reexamine the structure, size, and locality distributions of the world's hydrocarbon reserves.

Thermal conductivity, heat capacity per unit volume and phase behavior of Shtokman gas condensate were investigated at high pressure up to 1800 MPa in the temperature interval of 245-373 K using the transient hot-wire method. No crystallization was observed in the sample. The glass transition process in the Shtokman gas condensate takes place in the thermobaric interval which lies outside the range of temperatures and pressures corresponding to the production and transport of the gas condensate.

One of the most important questions in the frame of the concept of deep abiogenic origin of hydrocarbons is how hydrocarbons generated under the upper mantle conditions could migrate upward to the Earth's crust to form hydrocarbon deposits. Two different ways of fluid migration were proposed and simulated - slow migration during hundreds of years and fast migration-eruption. Influence of the fluid's migration speed on the final hydrocarbon mixture composition was studied. The received results show that the relative chemical composition of the hydrocarbon mixtures probably does not depend on the cooling conditions (the speed of the fluid migration).

Many countries have realised that biogas as a source of energy is an important component for sustainability transition. However, the total production volume of biogas is still relatively low. Such slow development raises a fundamental question—what are the current barriers hindering the wider uptake of biogas as a source of energy? In order to answer the question, a systematic state-of-the-art review of the barriers was conducted based on the Scopus database. The results of the review were summarised by country and were divided into two broad categories: developed and developing economies. Each group was analysed separately according to six types of barriers: (1) technical, (2) economic, (3) market, (4) institutional, (5) socio-cultural, and (6) environmental barriers. By analysing the barriers through different contexts, the most frequent and crucial constraints the biogas industry currently faces were identified and integrated into a systematic classification. In addition, possible solutions on how to overcome the most critical barriers were added.

The chemical interaction of hydrocarbon systems and iron-bearing minerals was investigated under extreme upper mantle pT conditions. As a result, the formation of iron carbide and iron hydride was detected. The experiments were carried out in diamond anvil cells with laser heating. Natural crude oil from the Korchaginskoe deposit and a synthetic mixture of paraffin hydrocarbons were used as hydrocarbon systems and pyroxene-like glass and ferropericlase (Fe-57 enriched) were used as iron-bearing minerals. The experiments were carried out in the pressure range of 26-95 kbar and the temperature range of 1000-1500 degrees C (+/- 100 degrees C). The formation of iron hydride was detected at pressure of 26-69 kbar (corresponds to a depth of 100-200 km), and a mixture of iron carbide and iron hydride is formed at pressure of 75-95 kbar (corresponds to a depth of 210-290 km). The formation of iron hydrides and carbides through the interaction of hydrocarbon systems with iron-bearing minerals may indicate the possible existence of these compounds in the upper mantle.

The photochemical reaction of hydrocarbons was found to play an important role in the experiments with the synthetic petroleum conducted in Diamond Anvil Cell (DAC). Raman spectroscopy with a green laser (514.5 nm) was used for in situ sample analysis. This photochemical effect was investigated in the pressure range of 0.7-5 GPa, in the temperature interval from the ambient conditions to 450 degrees C. The power of laser used in these experiment series was from 0.05 W to 0.6 W. The chemical transformation was observed when the necessary threshold pressure (similar to 2.8 GPa) was reached. This transformation correlated with the luminescence appearance on the Raman spectra and a black opaque spot in the sample was observed in the place where the laser focus was forwarded. The exposure time and laser power (at least in the 0.1-0.5 W range) did not play a role in the 0.1-0.5 GPa range.