NEW CORROSION INHIBITORS BASED ON AMINES AND AMIDES

In this work, new inhibitors of metal corrosion in sulfuric acid media are investigated depending on the duration of the process, inhibitor concentration and temperature. The main parameters of the synthesis of new corrosion inhibitors for metals of grade St.3 and St.12 with the use of amine and amide-containing organic substances have been determined, and methods for preparing these inhibitors have been described. The physicochemical properties of amine and amide containing organic inhibitors of corrosion and salt deposition in acidic process media have been studied.

Influence of the electromagnetic field on the corrosion of low-carbon steel in aqueous mineralized media and on the crystallization of calcium carbonate in the presence of iron(II) ions

The influence of the electromagnetic field (EMF) on the corrosion of structural carbon steel in a 3% aqueous solution of sodium chloride in the presence of CO2 was studied. It is shown that the EMF increases the corrosion rate of steel by 1.13 times in a 3% aqueous solution of NaCl in the presence of CO2. When Ca2+ ions are added to the solution, the corrosion rate of steel decreases under the influence of an electromagnetic field. It is assumed that the formation of CaCO3 in the near-surface layer of the solution and its adsorption on the metal surface prevents the development of corrosion. The influence of the electromagnetic field generated in the frequency range from 100 to 200 kHz on the crystallization of CaCO3 from supersaturated aqueous solutions on the model system CaCl2 – NaHCO3 – FeSO4 is studied. It was found that Fe2+, rather than EMF, has a more significant effect on salt deposition. The efficiency of the effect of Fe2+ on the inhibition of salt deposition in the model of mineralized water CaCl2-NaHCO3 is 11.5% higher than when exposed to EMF. During the crystallization of CaCO3, the predominant formation of aragonite is observed. In the presence of iron ions and under the influence of EMF, there was a decrease in the formation of aragonite and an increase in the formation of calcite and vaterite. Keywords: electromagnetic field; corrosion; carbon steel; iron ions; scale deposition; crystallization; calcium carbonate.

Geochemical and hydrogeological parameters informativity in oil and gas geology

The article discusses the fundamental possibilities of using the results of geochemical and hydrogeochemical studies of organic matter, oils and waters in oil and gas geology, including for objects at the stage of development. It is shown that complex geochemical studies of oils and waters make it possible to get more correct conclusions about the presence or absence of fluid-dynamic connectivity of different horizons. Studies of organic matter and oils allow (by basin modeling instrument) to understand the contribution of different source rocks to formation of oils of different reservoirs. Hydrogeochemical studies of associated waters and waters used in the reservoir pressure maintenance system in a complex of works not only actively complements the knowledge about the presence or absence of fluid-dynamic connections between reservoirs and production objects, but also make it possible to predict, for example, salt deposition on equipment and in the reservoirs, and therefore allow you to prevent the possibility of unwanted salt deposition. The conclusions are based on the results of comprehensive geological and geochemical studies carried out by the authors for one of the deposits of the Krasnoleninsky arch of Western Siberia, which is at the development stage, as well as on the previous experience of the authors.

Microscopic Characterization of Bioactivate Implant Surfaces: Increasing Wettability Using Salts and Dry Technology

The surface topography of dental implants plays an important role in cell-surface interaction promoting cell adhesion, proliferation and differentiation influencing osseointegration. A hydrophilic implant leads to the absorption of water molecules and subsequently promotes the adhesion of cells to the implant binding protein. Dried salts on the implant surfaces allow one to store the implant surfaces in a dry environment while preserving their hydrophilic characteristics. This process has been identified as “dry technology”. The aim of the present study is to describe from a micrometric and nanometric point of view the characteristics of this new bioactivated surface obtained using salts dried on the surface. Topographic analysis, energy-dispersive X-ray spectroscopy, and contact angle characterization were performed on the samples of a sandblasted and dual acid-etched surface (ABT), a nanosurface (Nano) deriving from the former but with the adding of salts air dried and a nanosurface with salts dissolved with distilled water (Nano H2O). The analysis revealed promising results for nanostructured surfaces with increased wettability and a more articulated surface nanotopography than the traditional ABT surface. In conclusion, this study validates a new promising ultra-hydrophilic nano surface obtained by sandblasting, double acid etching and surface salt deposition using dry technology.

Prevention of salt deposition in corrosive medium of produced water in oil-gas production

Produced water isolated from the oil in oil-gas production is pumped into the injection wells after cleaning from salt deposits and mechanical impurities. In the mixture of high-mineralised produced water, salt deposits making the technological equipment and pipes useless while gathering and transportation, reduce the permeability of injection wells. Carried out experimental researches show that for each ton it is necessary to pump 100 g of KD-7 inhibitor to prevent salt deposition in the mixture of produced water. Technological processes should be performed in a closed system, and the territories contaminated with oil and produced water cleaned and equipped well.

Development of new inhibitor to prevent salt deposition

The inhibitors of inorganic mineral sediments based on orthophosphate acid, monoamid of sulphuric acid (MSA) and carboxymethylcelluloze (CMC) have been developed. Created compositional inhibitors of salt deposition are transparent, fluid water solution with 14.5–22.0 % concentration. To specify the efficiency of developed salt deposition inhibitors, the agent capacity to keep cations of calcium in the volume of artificially prepared mineral waters of carbonate and sulphate types modelling produced water within oil fields has been evaluated. It was defined that adding 20–20 mg/l of developed compositions into the solutions of calcium sulphate provides high protection effect. Inhibitors’ protection capacity using the compositions in the charge of 20 mg/l in sulphate water comprises 89.6–96.8 %, and in the carbonate water - 87.8–92.6 %. Using 25 mg/l of these compositions, protection capacity of the inhibitors in sulphate water reaches up to 94.5–98.7 %, and in carbonate water - 92.5–96.8 %. Protection effect of inhibitors in case of using 30 mg/l of the compositions comprises 98.3–100 % in sulphate water, and 96.8–100 % in carbonated one as well.

Depositional environments and salt-thickness variations in Urmia Lake (NW Iran): Insight from sediment-core studies

Urmia Lake is a large-scale hypersaline lake that experienced a drastic water-level fall due to natural and anthropogenic forces during the last two decades. Construction of a causeway in the central part of the lake after 1989 has divided the lake into northern and southern parts and caused an extreme change of the lake hydrochemical system. Precipitation of evaporite minerals as crust on the lake floor was caused by the combination of lake level fall and increasing water salinity. However, some parameters controlling rates of salt deposition and dissolution and temporal and spatial variation in salt thickness in Lake Urmia are poorly understood. This study reviews 90 sediment cores from various parts of the lake to put forward a better understanding of the salt depositional system and salt thickness variations in the basin for the last 40 years (1977–2017). Our results indicate that the sedimentary system of Urmia Lake changed rapidly during the last two decades from a permanent hypersaline lake with predominantly fast terrigenous–biochemical sedimentation to a seasonally changing playa sedimentary environment with predominance of evaporite minerals. These changes are responsible for rapid salt deposition that generated a salt-crust with a maximum thickness of 2.95 m overlying Holocene terrigenous sediments. The salt-crust thickness and the water depth have a positive correlation for water depth greater than 1 meter, which means that salt-crust thickness increases where water depth increases. While the thickness of shallow deposits are affected by fresh-water dissolution. In addition, the average salt precipitation rate in the northern and the southern parts of the lake is 466 and 266 times higher, respectively, than the average (0.3 mm/y) sedimentation rate before the lake shrinkage. Similar to other large hypersaline lakes such as the Great Salt Lake (USA) and the Aral Sea (Central Asia), the manmade intervention at Urmia Lake (damming of the catchment, extension of agricultural fields, and causeway construction in the middle part of the lake) threatens its further hydrologic existence.