Asphaltene-resin-paraffin deposition (ARPD) is a complicated and prevalent issue in the oil and gas industry, impacting the efficiency and integrity of petroleum extraction, production, transportation and processing systems. Considering all witnessed ARPD problems in Azerbaijan oil fields, this paper proposed a chemical method and optimized the type and concentration of chemical inhibitors. Then, the effect of selected chemical reagents on inhibiting the ARPD amount and thus enhancing oil recovery was detected by reservoir simulation during both waterflooding and CO₂ flooding production. Three new chemical compounds (namely, Chemical-A, Chemical-B and Chemical-C) were examined in laboratory conditions, and their impact on rheological properties of high-paraffin oilfield samples of Azerbaijan (X, Y and Z) were investigated. Experimental results show that Chemical-C with a concentration of 600 g/t has the best efficiency for alleviating the problems. After adding Chemical-C to the crude oil, the freezing point of oil was decreased from 12 °C to (−4) °C, the ARPD amount declined from 0.185 to 0.016 g, and oil effective viscosity was reduced from 16.2 mPa·s to 3.1 mPa·s. It was determined that for water and CO₂ flooding, higher injection pressure resulted in reduced asphaltene precipitation. Adding the selected ARPD inhibitor, the oil recovery for waterflooding can increase from 52% to 62%, while it can rise from 55% to 68% for CO₂ flooding.

Experiences in the production, transportation and preparation of crude oil for transportation have shown that specific problems arise related to their mixing, including water contamination. In recent years, interest in studying these problems has significantly increased, mainly due to the development of extraction technologies for heavy oil samples and bitumen. Along with various difficulties encountered during the pipeline transportation of complex rheological crude oil blended with each other and with light oil, including condensate (such as sedimentation, etc.), imbalances are also observed during storage, as well as in the processes of delivery and reception. During the dehydration of oil mixtures, a synergistic effect is observed in the consumption of demulsifier. The article investigates, in accordance with international standards and based on laboratory tests, how the physico-chemical properties (density, viscosity, freezing point, saturated vapor pressure, chemical composition) of mixtures formed by blending various grades and compositions of Azerbaijani oil examples with each other and with condensate change and how the efficiency of dehydration of oil mixtures is affected by the mixing ratio of the oil involved. It was found that the quality indicators (physico-chemical parameters) of oil mixtures differ non-additively from the initial parameters of the blended products and in some cases, this difference is even observed with anomalies. Moreover, depending on the mixing ratio of the oil, variations in the consumption of demulsifier were also identified.

Asphaltene-resin-paraffin deposition (ARPD) is a complicated and prevalent issue in oil and gas industry, impacting the efficiency, integrity of petroleum extraction, production, transportation and processing systems. Considering all witnessed ARPD problems in Azerbaijan oil fields, this paper proposed a chemical method and optimized the type and the concentration of chemical inhibitors. And then the effect of selected chemical reagent on inhibiting the ARPD amount and thus en-hancing oil recovery was detected by reservoir simulation during both waterflooding and CO2 flooding production. Three new chemical compounds (namely, Chemical-A, Chemical-B and Chemical-C) were examined in laboratory conditions and their impact on rheological properties of high-paraffin oilfield samples of Azerbaijan (X, Y and Z) were investigated. Experimental results show that Chemical-C with concentration of 600 g/t has the best efficiency for alleviating the problems. After adding Chemical-C to the crude oil, the freezing point of oil is decreased from 12 °C to (-4) °C, ARPD amount is declined from 0.185 to 0.016 g and oil effective viscosity is reduced from 16.2 mPa·s to 3.1 mPa·s. It is determined that for water and CO2 flooding, higher injection pressure resulted in reduced asphaltene precipitation. Adding selected ARPD inhibitor, the oil recovery for waterflooding can increase from 52% to 62%, while it can rise from 55% to 68% for CO2 flooding.

In this study, formation water sample No. 1082 from the Narimanov OGPD, together with crude oil samples from the Bulla-Deniz and Muradkhanli fields, was examined under laboratory conditions to evaluate the efficiency of chemical reagents. The Alkan-318 demulsifier, Marza-1 inhibitor, Difron-4201 depressor additive, and a combined ADM composition (Alkan-318 + Difron-4201 + Marza-1 in a 1:1:1 ratio) were tested for their effects on water separation, corrosion inhibition, sulfate-reducing bacterium activity, paraffin deposition, and pour point depression. Comparative experiments showed that the ADM composition demonstrated superior performance over individual reagents at equal concentrations. At an optimal dosage of 600 g/t, the ADM composition reduced the residual water content (mass fraction) of Bulla-Deniz (75% initial water cut) and Muradkhanli (41% initial water cut) crude oils to 0.1 wt.% and 0.8 wt.%, respectively, after thermochemical treatment. The depressant performance was evaluated based on the degree of pour point reduction (ΔT, °C) relative to untreated oil. At optimal concentrations, Difron-4201 and the ADM composition reduced the pour point by 9.0–10.0 °C, demonstrating the superior efficiency of the multifunctional composition compared to individual additives. Corrosion tests revealed that Marza-1 and ADM provided up to 99.9% protection in aggressive H₂S and CO₂ environments, while ADM also exhibited a nearly complete bactericidal effect (99.8%) against sulfate-reducing bacteria, highlighting its multifunctional efficiency.

In this study, formation water sample №1082 from the Narimanov OGPD, together with crude oil samples from the Bulla-Deniz and Muradkhanli fields, were examined under laboratory conditions to evaluate the efficiency of chemical reagents. The Alkan-318 demulsifier, Marza-1 inhibitor, Difron-4201 depressor additive, and the combined ADM composition (Alkan-318 + Difron-4201 + Marza-1 in a 1:1:1 ratio) were tested for their effects on water separation, corrosion inhibition, sulfate-reducing bacteria activity, paraffin deposition, and pour point depression. Comparative experiments showed that the ADM composition demonstrated superior performance over individual reagents at equal concentrations. At an optimal dosage of 600 g/t, Alkan-318 and the ADM composition reduced residual water in Bulla-Deniz (75% water cut) and Muradkhanli (41% water cut) oils to 0.1% and 0.8%, respectively. For pour point depression, Difron-4201 (900 g/t) and ADM (600 g/t) achieved efficiencies of 169.2% and 176.9% in Bulla-Deniz oil, and 151.4% and 170.0% in Muradkhanli oil. Regarding deposit prevention, ADM reached 95.4% and 96.9% efficiency, significantly exceeding individual reagents. Corrosion tests revealed that Marza-1 and ADM provided up to 99.9% protection in aggressive H₂S and CO₂ environments, while ADM also exhibited a nearly complete bactericidal effect (99.8%) against sulfate-reducing bacteria, highlighting its multifunctional efficiency.

The formation of oil–water emulsions following reservoir-water breakthrough is widely observed during oil production. The viscosity of these polydisperse systems may increase sharply with increasing water cut, creating substantial operational difficulties in well-gathering systems and increasing hydraulic pressure losses. The rheological behaviour of oil emulsions is influenced by the phase ratio, flow velocity, degree of dispersion, temperature and several other parameters. However, no generally applicable model is currently available for describing the rheological behaviour and predicting the properties of oil emulsions, which are anomalous and rheologically complex systems. Therefore, developing a reliable method for estimating the viscosity of stable emulsions while accounting for increasing water content is of considerable practical importance. This study evaluates existing empirical correlations used to characterise the rheological properties of oil emulsions. The analysis shows that their application under oilfield conditions is associated with several limitations and that, in many cases, they are unsuitable for solving practical engineering problems. Accordingly, a mathematical model was developed and validated for estimating and predicting the viscosity of structurally stable oil emulsions as a function of water cut. The proposed model demonstrated good agreement with the experimental data and may be used for engineering calculations related to the production and transportation of water-cut oil.