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The paper considers the process of hydrate-paraffin deposits formation in oil wells. Due to the research with the author's specially designed laboratory equipment – an experimental installation containing a technological unit and an information-measuring system, the most favorable pressure-temperature conditions of hydrate formation in a wide range of pressure (0.1–120 MPa) and temperature (from –20 to +80 °C) were determined. The experimental results made it possible to determine the conditions required for hydrate deposits and iron (Fe) oxides in the range of temperature from –15 to +60 °C and pressure from 0 to 60 MPa. These results are confirmed by thermodynamic calculations of the oil-gas-hydrate phase equilibria in the annulus of the well. Data processing was performed using the methods of correlation, dispersion and regression analysis, which allowed comparing the processes of hydrates and iron (Fe) oxides formation in the annulus of oil wells. The results of the study can be used to prevent and eliminate hydrate-paraffin plugs in the downhole equipment of oil wells, and also to determine the operation mode of the well for long-term operation of the downhole equipment without complications, accidents and stops for repair works, which reduces downtime.

The object of research is hydrocarbon solvents for the elimination of paraffin-hydrate deposits. The chemical methods of control of paraffin-hydrate deposits, in particular, application of hydrocarbon solvents are considered in the article. Studies of the effect of various chemical reagents on the dissolution of hydrate formations using a laboratory installation at different thermo-baric regimes, closest to the real conditions of the pipe space of oil and gas wells: the temperature varied discretely from –10 to +40°C and pressure from 0 to 10 MPa. To study the effect of hydrocarbon solvents on the process of removing hydrate formations, the most rational methods of regression analysis and mathematical planning of the experiment were used – simplex-grid planning. The G-criterion of plan optimality was used, which includes 22 experiments. The synthesis of the plan was implemented by numerical methods on a software-controlled device for information processing. The use of such methods makes it possible to reasonably organize experimental research, adjust the time, equipment, materials and perform the required number of experiments. The results of measurements are shown in the diagrams for each solvent separately. The obtained data allowed to a priori substantiate the choice of the optimal variant of application of chemical reagents for complete dissolution and removal of paraffin-hydrate formations from the surface of the internal well equipment. Analysis of the data shows that the solubility reagents butyl cellosolve and ethylacetat solvents, which can be recommended for wide application in the oil and gas industry, are characterized by the highest solubility and efficiency for removal of paraffin-hydrate deposits from the surface of well equipment. An important fact is that the consumption of the proposed solvents perоne well operation is not more than 4m3, which is 2–3 times less than in other known analogues. The use of new solvents also allows to increase the inter-cleaning period of the well more than 2–3 times, which reduces the cost of extracted products.

Today considerable experience in the development of tar sands is accumulated. However, well-known mining technologies do not cover the entire depth range of natural bitumen deposits. In addition, there are significant energy-intensive technol 309 ogies and negative environmental impacts. In view of this, the purpose of this work is to improve the method of extracting natural bitumen in site for a deposit interval of 75-200 m and to substantiate the basic technological scheme of this method. The proposed method of extracting bitumen from poorly cemented reservoirs in the depth range of 50 – 400 m provides: creation of artificial production; the transfer of the rock into the water mixture composition under the action of high pressure jets of a heated mixture of water, a hydrocarbon solvent and a flotation agent; separation from the rock and concentration of bitumen in the production as a result of its heating, dissolution and flotation; selection of depleted bitum slurry from the production by gas lift. The proposed method of extracting bitumen is the transfer of the rock at the its occurrence site to the suspension condition on the excavation created by the hydraulic production method, separation and concentration of bitumen by dissolving it with a heated hydrocarbon solvent and a flotation agent (hydrocarbon reagents) and extraction in composition of the depleted rock slurry to the surface by the gas lift method. As the preliminary calculations show, the proposed method will allow the efficient extraction of bitumen and highly viscous oil from weakly cemented reservoirs in the depth range of 50-400 m. Also, the proposed technology creates the preconditions for the development of oil sands at a depth of 75-200 m since there is currently no effective technology for the interval. In addition, it can significantly reduce energy costs, environmental pollution and greenhouse gas emissions.

Absence of full-scale tests results on real models that adequately reflect the physical and thermodynamic processes occurring in the intertubular space during oil production does not permit to develop effective technological methods as well as organizational and technical measures for the prevention and reduction of the probability of hydrate formations, corrosion-active against the surface of casing, and tubing in the annular space of oil wells. To extend the lifetime of oil and gas facilities, the information-measuring system and equipment have been developed, which permit to fully approximate the conditions and modes of hydration of iron and its oxides to real down-hole processes and characteristics, which make it possible to investigate hydrate formations with a wide probability in a wide variation range of temperature and pressure. Obtained through information and measuring system, the results of the statistical experiments gave the opportunity to determine the conditions necessary for hydrate formations of iron (Fe) and its oxides in the temperature range from −15 to +60 °C and a pressure of 0–60 MPa, which confirmed thermodynamic calculations of phase equilibria in the annular space of wells known from the literature.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive loss of cortical, brain stem and spinal motor neurons that leads to muscle weakness and death. A previous study implicated CACNA1H encoding for Cav3.2 calcium channels as a susceptibility gene in ALS. In the present study, two heterozygous CACNA1H variants were identified by whole genome sequencing in a small cohort of ALS patients. These variants were functionally characterized using patch clamp electrophysiology, biochemistry assays, and molecular modeling. A previously unreported c.454GTAC > G variant produced an inframe deletion of a highly conserved isoleucine residue in Cav3.2 (p.ΔI153) and caused a complete loss-of-function of the channel, with an additional dominant-negative effect on the wild-type channel when expressed in trans. In contrast, the c.3629C > T variant caused a missense substitution of a proline with a leucine (p.P1210L) and produced a comparatively mild alteration of Cav3.2 channel activity. The newly identified ΔI153 variant is the first to be reported to cause a complete loss of Cav3.2 channel function. These findings add to the notion that loss-of-function of Cav3.2 channels associated with rare CACNA1H variants may be risk factors in the complex etiology of ALS.