Since most of the fields in the Absheron peninsula of the Republic of Azerbaijan are at the final stage of development, an inevitable reduction in hydrocarbon production is expected. An increase in the proportion of formation water in well production, the presence of intra-reservoir, annulus and other cross-flows in this region, in most cases, is associated with inefficient isolation work. The development of effective recipes for cement slurries with controlled rheological properties is relevant. Natural zeolite was used as an additive to control the rheological properties of cement slurries. A feature of zeolites is the presence of a system of regular channels and communicating cavities capable of holding ions, atoms and molecules of substances, whose size corresponds to the size of free space. Zeolite (clinoptilolite) has the following properties: adsorption ‒ the ability to absorb and release various substances; ion exchange ‒ the ability to exchange cations; catalytic ‒ the ability to speed up chemical reactions. In addition, clinoptilolite has a molecular sieve effect that transmits (filtration) and absorbs molecules of various substances selectively. In the course of experiments, the effects of zeolite dispersions on the physicochemical parameters of cement stone were studied. When regulating the rheological properties of cement slurries with zeolite additives, it is necessary to determine the effect of thermobaric factors on the values of these properties. In studies to assess the effect of temperature on the rheological properties of zeolite-cement mortars, they were carried out for the temperature range of 25÷75 ℃

The practice of cementing the bottomhole zone of wells in unstable formations shows that cement stone, designed to ensure rock stability, is the weakest link and can easily be destroyed under the influence of various loads. Such loads include perforation of the production string, hydraulic fracturing and other technological operations. The main factor contributing to the destruction of cement stone under dynamic loading is its low deformation properties. Repeated or cyclic loads cause fatigue phenomena in cement stone and lead to the formation and development of fractures in it. However, currently used cementing materials based on Portland cement have poor resistance to impact loads and low tensile strength. Therefore, the need to create an effective barrier with sand when cementing the bottomhole zone by developing reliable cementing compositions resistant to dynamic loads is relevant task. Therefore, task of current interest is the need to create an effective sand barrier when cementing the bottomhole zone by developing reliable cement compositions that are resistant to dynamic loads. One of the promising ways to protect the integrity of cement stone during perforation and hydraulic fracturing is to control the physical and mechanical properties of the cement material by adding various types of chemical reagents into cement compositions. The object of the study is cement stone created in the bottomhole zone of sand-producing wells. Here, a scientifically applied problem, the purpose of which was to increase the plastic properties of the cement slurry and increase resistance to deformations, as well as crack resistance was solved. In this regard, it is necessary to study the influence of various additives on the processes of formation of the structure, as well as other rheological and physical-mechanical properties of the cement slurry and stone. The studies carried out are based on the use of local raw materials and residual materials, as well as the correct determination of perforation time accordingly. In order to solve the problem, experiments in laboratory conditions were carried out. A special plugging cement of G-I-100 grade was used in the experiments. To achieve indicators aimed at improving the plastic properties of the prepared cement stone, plasticizers were used. The use of the Bentomix 1275 plasticizer in wells preserves the natural structure and filtration properties of the formation, which helps to increase oil production volumes. The Bentomix 1275 plasticizer accelerates the timing of putting wells into operation, and there is an increase in total and current production due to improved formation opening. The effect is due to the increase in the length of perforation channels in the formation due to the absence of fragments of cement stone, as well as an increase in the efficiency of fastening due to an increase in the structure in oriented zones

Hydrate formation and erosion-related pipe wear are critical operational challenges in natural gas pipelines. This study evaluates a pyrocondensate-based liquid composition modified with fine clay particles as a dual-function formulation for apparent hydrate-onset control and erosion-wear mitigation. The liquid phase contains pyrocondensate solvent, heavy gasoline fraction, and white oil. Laboratory screening was performed for composition ranges including 60/20/20 and 65/15/20 with formulations at reported dosages of 20–25 g/1000 m³. Under the applied procedure, visible hydrate formation for model gas samples was suppressed down to −24 °C with the 60/20/20 formulation. For a field gas sample from well No. 422, the 65/15/20 formulation shifted the observed apparent hydrate-onset temperature from +6 °C to approximately −20 °C at a dosage of 20 g/1000 m³. To mitigate erosion-wear, fine clay particles were added at 10 wt.% of the liquid composition. Laboratory tests demonstrated increased visual erosion-onset time in gas–liquid–solid flows. A preliminary four-month field application on well No. 422 recorded no hydrate formation or visible erosion-related complications. The results demonstrate the empirical potential of this dual-function composition under the investigated conditions.

Lost circulation remains a major challenge during well construction, often leading to non-productive time, increased material consumption, and additional treatment costs. In field practice, the selection of lost circulation materials (LCMs) is still largely based on empirical rules or laboratory testing; however, these approaches are not always suitable for rapid decision-making under variable downhole conditions. This study presents a physics-guided surrogate modeling framework for predicting fracture sealing performance and supporting injection strategy selection. The approach combines laboratory observations with coupled computational fluid dynamics and discrete element method (CFD-DEM) simulations to represent both measured behavior and a broader range of mechanically consistent sealing scenarios. The final dataset included 300 cases, comprising 45 physical experiments and 255 CFD-DEM-generated synthetic cases. A hybrid machine learning architecture based on Temporal Convolutional Networks and Artificial Neural Networks was developed to predict sealing pressure under different material and fluid conditions. The model achieved an R² of 0.89 and a mean absolute percentage error of 6.4%, while showing 94% agreement with laboratory-based recommendations for injection strategy. The proposed framework can therefore serve as a rapid engineering support tool for preliminary formulation screening and a more computationally efficient digital workflow for fracture sealing design in drilling operations.

Capillary hysteresis significantly affects oil displacement efficiency in porous media by influencing residual oil trapping, relative permeability scanning behavior, and saturation history-dependent flow resistance. This paper evaluates core-scale EOR strategies designed to influence capillary trapping and saturation-history-dependent displacement behavior, with the aim of increasing displacement efficiency using sandstone core samples representing seven parent-core materials. Reservoir conditions were simulated through conventional high-salinity brine flooding, low-salinity waterflooding (LSWF), chemical EOR using alpha olefin sulfonate (AOS) surfactant, and low-salinity water-alternating-gas (WAG) flooding with nitrogen. After LSWF, separate batches of core samples were retrieved from the remaining material of the respective parent cores C1 to C7. Thus, the CEOR and N₂-WAG operations were conducted on different core samples that were separately processed and initialized. HSWF recovered an average of 53.15 ± 5.42% of OOIP at 56,300 ppm salinity and left a residual oil saturation of 34.57 ± 2.99% pore volume (PV). Among the brines examined, 7600 ppm provided the highest recovery of 61.31 ± 5.69% OOIP and left a residual oil saturation of 28.52 ± 3.36% PV. With further dilution of the brine solutions, performance decreased to 54.50 ± 5.96% OOIP recovery at 3000 ppm and 49.00 ± 6.24% OOIP at 1000 ppm. Further tests showed even worse results due to increasing solid content in the effluent, permeability impairment, and swelling of cores. Volume-weighted mean effluent solids content was 13.99 mg/L at 7600 ppm, 95.01 mg/L at 3000 ppm, and 225.00 mg/L at 1000 ppm. Micro-CT imaging of C1 for 3000 ppm pre- and post-flood cores indicated localized restriction of the resolved pore space. These results show that swelling and migration of fines contributed to the adverse responses at the lowest salinity. In contrast, a 0.5 wt% AOS formulation on a commercial-product basis (0.195 wt% active AOS) recovered 69.30 ± 6.32% OOIP with a residual oil saturation of 22.60 ± 4.00% PV, while N₂-WAG recovered 73.06 ± 6.23% OOIP with a residual oil saturation of 19.82 ± 4.01% PV. Consequently, the overall outcomes correlate with less residual trapping and better displacement under salinity control, interfacial-tension reduction, and cyclic gas–water saturation changes.

Relevance. The need to understand the mechanisms of reducing effective gas permeability, gas and condensate flow rates due to the formation of a liquid hydrocarbon phase and accumulation of liquid around underground gas storage wells, as well as the entire range of gas condensate wells at bottomhole pressure below the liquid dew point. Aim. To develop a technology for restoring the parameters of gas injection and extraction from underground gas storage wells by cleaning the bottomhole zone of wells from accumulated liquid. Methods. Analytical studies, laboratory analyzes of well fluid samples, field tests, statistical methods. Results and conclusions. It is shown that since underground gas storage facilities are created on depleted gas condensate deposits, their wells have most of the operational characteristics of gas condensate wells in general. Along with this, the article also examines and reflects a number of features characteristic of a underground gas storage well. The authors have proposed a technology for using an inexpensive solvent such as methanol to increase the production rate of wells by cleaning the bottom-hole zone of the well. The criteria for selecting candidate gas condensate wells for applying the technology are indicated. The authors give the recommendations on parametric requirements and methanol consumption rates for wells subject to selection for the application of technology to increase production by cleaning the bottom-hole zone of gas wells from liquid plugs. It was established that in underground gas storage wells with operating pressure in the range of 7.0–16.0 MPa, ideal conditions are created for retrograde settling of liquid. The paper provides the ınformation on the progress of field tests, the results obtained and their analysis. By applying the technology in field conditions, the result obtained was to double the injectivity of a underground gas storage well during gas injection. It is shown that if before the impact the share of the experimental well in the total injection volume was 0.51–0.5.6%, then after the impact this figure changes in the range of 0.84–1.72%, that is, the increase was from 1.5 to 3 once. In this regard, a conclusion was also made about an increase in the well flow rate during the gas withdrawal season.