Oil Formation Research Articles

The application of pH-responsive hyaluronic acid-based essential oils hydrogels with enhanced anti-biofilm and wound healing

pH could play vital role in the wound healing process due to the bacterial metabolites, which is one essential aspect of desirable wound dressings lies in being pH-responsive. This work has prepared a degradable hyaluronic acid hydrogel dressing with wound pH response-ability. The aldehyde-modified hyaluronic acid (AHA) was obtained, followed by complex mixture formation of eugenol and oregano antibacterial essential oil in the AHA-CMCS hydrogel through the Schiff base reaction with carboxymethyl chitosan (CMCS). This hydrogel composite presents pH-responsiveness, its disintegration mass in acidic environment (pH = 5.5) is 4 times that of neutral (pH = 7.2), in which the eugenol release rate increases from 37.6 % to 82.1 %. In vitro antibacterial and in vivo wound healing investigations verified that hydrogels loaded with essential oils have additional 5 times biofilm removal efficiency, and significantly accelerate wound healing. Given its excellent anti-biofilm and target-release properties, the broad application of this hydrogel in bacteria-associated wound management is anticipated.

Pressure drop prediction by a polynomial model for two-phase flow in vertical oil wells

In this paper, a polynomial model is developed to predict the pressure drop in oil wells with two-phase flow. The variables used in the model are gas-oil ratio production, oil production, tubing diameter, solution gas-oil ratio, oil formation volume factor, and oil viscosity. A polynomial model is presented to predict the pressure drop with a coefficient of determination of 0.9901. The residual analysis and level surfaces of the pressure drop against the polynomial model's input variables are presented to validate the model. A regression of the experimental and predicted pressure drops values using the polynomial model is presented. This model contributes to a simpler methodology for the calculation of pressure drops and the consequent application in the modeling of production curves in oil wells for NODAL analysis.

Optimized artificial neural network application for estimating oil recovery factor of solution gas drive sandstone reservoirs

The most crucial aspect in determining field development plans is the oil recovery factor (RF). However, RF has a complex relationship with the reservoir rock and fluid properties. The application of artificial neural networks is able to produce complex correlations between reservoir parameters that affect the recovery factor. This research provides a new approach to improve the accuracy of the ANN model in the form of steps including removing outlier data, selecting input parameters, selecting transferring functions, selecting the number of neurons, and determining hidden layers. By applying these steps, an ANN model was selected with nine input parameters consisting of oil viscosity, water saturation, initial oil formation volume factor, formation thickness, initial pressure, permeability, specific gravity of oil, porosity, and original oil in place. Furthermore, based on the correlation coefficient, a tangent sigmoid transferring function, 30 neurons, and two hidden layers were determined. The proposed ANN correlation gives the best accuracy compared to the previous correlations. This is proved by the highest correlation coefficient of 0.91657.

PARAGENETIC RELATIONS OF COAL-BEARING AND OIL- AND GAS-BEARING FORMATIONS (EXAMPLE OF THE DON-DNIEPER TROUGH)

The relationship between coal-bearing and oil-and-gas-bearing formations is a fundamental problem in geology. The aim of this study is to determine the paragenetic relationships between hydrocarbons with coal-bearing sediments. This is achieved through the analysis of hydrocarbon composition, hydrocarbons deposits distribution, connection with petrographic types and degree of coalification of the coal in the Don-Dnieper trough. It provides various examples of the coexistence and palaeogeographic connectivity of coal, oil, and gas-bearing formations, which is a widespread occurrence in many basins worldwide. During both peat accumulation and the transformation of organic matter from peat to coal, the Don-Dnieper trough was located in the equatorial range of paleo-latitudes. This observation is significant because it sheds light on the conditions that existed during the formation of coal in this region. This text describes the petrographic composition and degree of coalification of the concentrated and scattered organic matter in the Don-Dnieper trough. These characteristics determine the formation of liquid and gaseous hydrocarbons. Based on the distribution of hydrocarbon deposits in the Don-Dnieper trough, and their consistency with petrographic coal types and degree of coalification, carboniferous deposits are classified into several categories: coal-bearing, gas-carbon-bearing, coal-gas-bearing, gas-bearing, oil-gas-bearing, gas-oil-bearing, and oil-bearing. The distribution of coal deposits of a certain age, the degree of coalification, and the composition of organic matter are consistent with the presence of liquid or gaseous hydrocarbons. The additional data obtained strongly support the concept of a paragenetic connection between coal-bearing and hydrocarbon-containing formations.

A synergetic binary system of waste cooking oil-derived bio-based surfactants and its interfacial performance for enhanced oil recovery

Bio-based surfactants have garnered significant interest nowadays in wide applications particularly in the oil recovery field owing to their renewable property, outstanding surface/interface activity and eco-friendliness. The ultra-low interfacial tension between crude oil and brine is one of the key parameters for evaluating surfactants used in enhanced oil recovery. In this study, we developed a new binary surfactant system formulated by a bio-based zwitterionic surfactant (POA) and a bio-based nonionic surfactant (SOG), and the binary surfactant system exhibits a strong interfacial activity at a very low surfactant dosage. With the total surfactant concertation in a range of 0.1–3 g/L and the mass ratio of POA to SOG in a range of 5:5–9:1, the interfacial tensions of the binary system between crude oil and simulated formation brine could be significantly reduced to an ultra-low level (∼10−3 mN/m), indicating a strong synergistic effect between molecules in the binary system. Meanwhile, with the total surfactant concertation of 0.5 g/L and the mass ratio of POA to SOG of 7:3, the binary system demonstrates ultra-low interfacial tensions (∼10−3 mN/m) between crude oil and simulated formation brine at the temperature up to 80 ℃, NaCl up to 75 g/L and Ca2+ ions up to 20,000 mg/L, and the emulsification and oil film peeling ability are also improved compared with those of the individual POA and SOG. This study opens a new window for the binary bio-based surfactants and provides insights in designing and optimizing the cost-effective displacement systems for enhanced oil recovery with ensuring environmental sustainability.

Molecular Dynamics Simulation of Silicone Oil Polymerization from Combined QM/MM Modeling.

We outline a molecular simulation protocol for elucidating the formation of silicone oil from trimethlyl- and dimethlysilanediole precursor mixtures. While the fundamental condensation reactions are effectively described by quantum mechanical calculations, this is combined with molecular mechanics models in order to assess the extended relaxation processes. Within a small series of different precursor mixtures used as starting points, we demonstrate the evolution of the curing degree and heat formation in the course of polymer chain growth. Despite the increasing complexity of the amorphous agglomerate of polymer chains, our approach shows an appealing performance for tackling both elastic and viscous relaxation. Indeed, the finally obtained polymer systems feature 99% curing and thus offer realistic insights into the growth mechanisms of coexisting/competing polymer strands.

Oil Formation Volume Factor Empirical Correlations for some Libyan Crude Oils

Physical properties of reservoir fluid arenecessary for different field applications. Among those properties is the Oil Formation Volume Factor (Bo). It isone of important property for both reservoir andproduction engineering. In many situations, laboratorymeasurement is not possible either because ofunavailability of liquid oil samples or budget constraints,Hence, proper empirical correlations to predict formationvolume factor come to rescue. The purpose of thisexploration is to test the performance of the most commonpublished Oil Formation Volume Factor correlations forselected Libyan crude oils. Statistical analysis is thecriteria adopted for the evaluation in this study. Cross plottechnique is also applied to check the performance of thecorrelation and it gave the same index of the statisticalcriteria method. Accuracy of these correlations has been confirmed bycomparing the obtained results of these correlations withexperimental data gathered from our labs for Libyan oilreservoirs. It was observed that, there is acceptableagreement between predicted results with experimentalresults.

Experience of Paleotectodynamic Analysis of Rank Components of Mesozoic-Cenozoic Movements and Deformations Using the Example of the Central Part of Bukharo-Khiva Region

The article describes the methodological basis and some first experience results of applying paleotectodynamic analysis of tectonic movements rank components and deformations to study the features of geological development of a certain territory of the Bukharo-Khiva region central part in the Mesozoic – Cenozoic. The relevance of the work is determined by the need to revise the traditional methods of historical and structural analysis, based on which the conditions of formation and age of oil and gas structural traps are determined to improve the reliability of prognostic works. Paleotectodynamic analysis, as a new direction of studying the geologic evolution history, provides an assessment of the duration of manifestation of tectodynamic systems (paleotectonic stresses, tectonic movements and deformations) of different ranks in geologic history, study of the paleotectonic development of rank components of tectonic movements and deformations in the intervals of tectodynamic system action, determination of the relative age of formation of structural elements, their inheritance, as well as determination of the relative age of formation of structural elements, their inheritance, role or contribution to the geological evolution.The main indicator, on the basis of which the possibility to identify an independent (integral) tectodynamic system is determined, is the stress field type and deformation regime. In the Mesozoic – Cenozoic of the western part of the Tien Shan, five phases of alternating change of tectonic stress fields of the first (for this region) rank and associated deformation regimes were identified. In the first approximation, they correspond to: Early – Middle Jurassic, Late Jurassic, Cretaceous, Paleogene, and Neogene-Quaternary time. On this basis, the paper substantiates the necessity to revise and modify the classical methods of historical-structural (paleotectonic) analysis, which should be performed for each rank component separately, taking into account the interaction of both peer-to-peer and multi-rank elements. In this approach, the most important indicator is the feedback sign between different rank elements of tectodynamic systems. On the example of the central part of the Bukharo-Khiva oil-and-gas-bearing region, paleotectonic maps-schemes of three ranks for the above-mentioned time intervals were obtained. The previously unknown features of the structural plans of different horizons and their evolution in the Mesozoic – Cenozoic history were established. They served as a basis for further traditional historical-structural analysis with the construction of isopachic triangles along the selected intervals for each rank component in order to assess the tectonic conditions and time of formation of anticlinal oil and gas traps.

Shear-wave velocity prediction of tight reservoirs based on poroelasticity theory: A comparative study of deep neural network and rock physics model

The absence of shear-wave (S-wave) velocity in well log data limits the effective seismic characterization of lithology, petrophysical properties, and fluid distribution of tight reservoirs in the Chang 7 shale oil formations of Ordos Basin, west China. However, conventional rock physics models (RPMs), e.g., the Xu-White model, struggle to accurately obtain the key parameters such as pore aspect ratio in the process of S-wave velocity prediction. This work performs a comparative study of S-wave velocity prediction based on deep neural network (DNN) and RPM for such reservoirs. By employing the poroelasticity equations which are capable of describing elastic wave propagation in the complex reservoirs saturated with viscous fluid, the relation between elastic and petrophysical properties is established with a DNN-based method. This approach quantifies the connection between P-/S-wave velocities and rock properties. On the other hand, we reformulate the traditional Xu-White model by incorporating the decoupled Kuster-Toksöz (K-T) model and the poroelasticity equations with viscoelastic fluid in the modeling process. The variation of pore aspect ratio with depth is also considered to characterize the complex pore structures, which is appropriate for improving the accuracy of prediction. Log data from the three wells are considered for verification, of which results show that the S-wave velocity prediction methods help improve the final result. Aided by the DNN-based method, the prediction exhibits a better performance if the training data is sufficient. In particular, provided a small amount of measured S-wave data (even ten data points), the trained DNN model can also provide reasonable predictions.

Sesame lignans modulate aroma formation in sesame oil through the Maillard reaction and lipid oxidation in model systems

The unknown effect of sesame lignans on aroma formation in sesame oil via the Maillard reaction (MR) and lipid oxidation was investigated. Sesamin, sesamolin, or sesamol was added to 3 models: lysine+glucose (MR), cold-pressed sesame oil (SO), and MR + SO, and were heated at 120 °C for 60 min. All three lignans suppressed SO oxidation while increasing DPPH scavenging ability (p < 0.05). Lignans increased depletions of lysine and glucose and MR browning (p < 0.05). Lignans reduced most aroma-active pyrazines, aldehydes, ketones, alcohols, and esters (p < 0.05). Sesamol and sesamolin increased perceptions of the preferable aromas of nutty, roasted sesame, and popcorn while reducing the undesirable green and rancid aromas (p < 0.05). Sesamol demonstrated a stronger effect on lipid oxidation, MR browning, aroma formation, and sensory perception than sesamin and sesamolin. This study suggests that sesame lignans can modulate aroma formation and sensory perception of sesame oil by interacting with the MR and lipid oxidation pathways.

A Novel Method to Calculate Water Influx Parameters and Geologic Reserves for Fractured-Vuggy Reservoirs with Bottom/Edge Water

In practical oilfield production, the phenomenon of water influx typically shortens the water-free recovery period of wells, leading to water flooding and causing a sharp decline in the production well yields, bringing great harm to production. Water invasion usually occurs as a result of the elastic expansion of the water as well as the compaction of the aquifer pore space. However, it can be due to the special characteristics of fractured-vuggy reservoirs such as non-homogeneity and the discrete distribution of the pore spaces. It is challenging to use traditional seepage flow theories to analyze the characteristics of water influx. Also, reservoir numerical simulation methods require numerous parameters which are difficult to obtain, which significantly reduces the accuracy of the results. In this study, considering the driving energy for water influx, a water influx characteristic model was obtained by fitting a graph plate. Subsequently, an iterative calculation method was used to simultaneously obtain water influx volume and OOIP. The aquifer to hydrocarbon ratio was determined by fitting the water influx curve with the graphic plate. Results show that the calculation method is sensitive to the values of reservoir pressure and the crude oil formation volume factor. After applying the method to one field case, it was discovered that water influx performance can be characterized into two types, i.e., linear water influx and logarithmic water influx. In the early stages, the water influx rate of logarithmic water influx is greater compared to linear water influx. However, the volume and energy of waterbody are limited, and the water invasion phenomenon occurs almost exclusively within a short period after the invasion. On the other hand, the volume of waterbody invaded by linear water influx is larger, and it can maintain a stable rate of water influx. The results of the study can provide theoretical support for the waterbody energy evaluation and dynamic analysis of water influx, as well as the control and management of water in these types of reservoirs.

Effect of deodorization conditions on fatty acid profile, oxidation products, and lipid-derived free radicals of soybean oil

Oxidative stability is a key quality characteristic of edible oils, and the oil’s antioxidant capacity decreases during the deodorization stage. This study explores the changes in radical formation, molecular structure, oxidative characteristics, fatty acids, and main bioactive compounds in soybean oil during deodorization. The lag phase decreased, whereas the total amount of spins of free radicals increased as the deodorization time increased from 90 to 150 min. The total amount of spins and percentage of alkyl radicals varied dramatically under different times and temperatures (220 ∼ 260 ℃). Results showed that identifying and quantifying the formed radicals can provide useful information for monitoring and controlling oil oxidation in vegetable oil refining systems. Therefore, to control early oxidation events, maximize refined oil product yield, and reduce energy consumption in the refining plant, the priority should be to minimize temperature during the oil refining process and then shorten the deodorization time.

The study on mechanism of water–rock reaction in shale oil formation rich in alkaline minerals in Mahu Sag by using supercritical CO2

The Mahu Sag of Junggar Basin, China is rich in alkaline minerals. Generally, the water–rock reactions between hydraulic fluid and alkaline minerals during the hydraulic fracturing process will lead to the precipitation of minerals and block the pore or wellbore, thereby affecting the recovery efficiency. Supercritical carbon dioxide (ScCO2) regarded as a fracturing fluid can significantly improve the recovery of shale oil resources, but there is limited research on the reaction of ScCO2 to water and rock in shale samples rich in alkaline minerals. Therefore, ScCO2 treatment experiments were conducted on shale samples rich in alkaline minerals under 80°C and 10 MPa. Before the experiments, X-ray powder diffraction (XRD) was applied to characterise the mineral properties of the three shale samples. In addition, the duration time of ScCO2 treatment was set at 7 and 20 days to observe the treatment time impacts on the pore structure. Scanning electron microscopy (SEM) analysis and the Mann–Whitney U test were conducted before and after ScCO2 treatment. SEM images show the changes in pore structure. Opening pores are observed due to the interaction between the alkaline mineral and ScCO2. The Mann–Whitney U test shows the changes in fracture toughness. The changes in pore structure also play an important role in fracture toughness. This study investigated the ScCO2 impacts on shale samples rich in alkaline minerals and the analysis of changes in pore structure and fracture toughness can provide theoretical and data evidence to enable on-site optimisation of the ScCO2 fracturing scheme.

Selective lipase-catalyzed hydrolysis for removal of diglyceride in palm oil

Palm-based transformer oil is an environmentally friendly and renewable alternative to mineral-based oil for use as an insulating oil. However, the crystallization of palm oil at low temperatures can cause operational issues in transformers. In this research, low diglyceride palm oil is first proposed as a promising base stock for palm-based insulating oil to overcome this issue. The research focuses on the removal of diglycerides (DG) from palm oil by selective enzymatic hydrolysis under a solvent-free system. The results indicate that the lipase GS-250G specifically catalyzes only DG molecules without hydrolyzing TG molecules, despite TG molecules being more prone to hydrolysis than DG molecules due to their higher concentration in palm oil. This unique behavior is probably attributed to steric hindrance by bulky amino acids surrounding the catalytic pocket of lipase GS-250G. Under optimum conditions (30 °C, atmospheric pressure, water content of 16 wt%, agitation speed of 850 rpm, lipase loading of 0.005 wt%, and 4 h of reaction time), the lipase GS-250G reduced the DG content in palm oil from 7 % to 0.5 % with a degree of DG hydrolysis of 95 %. After purification, the final product was composed of 99 % triglyceride (TG). The cold stability test suggested that the nucleation and crystallization rate during the crystal formation of palm oil were reduced by decreasing the DG content. The finding suggests that the proposed procedure in this work is a rapid and environmentally sustainable method for DG removal, which can solve the major problem of palm oil. This discovery opens new opportunities for palm oil to be used as a raw material only for insulating oil but also for various palm based products.

Novel robust Elman neural network-based predictive models for bubble point oil formation volume factor and solution gas–oil ratio using experimental data

Novel robust Elman neural network-based predictive models for bubble point oil formation volume factor and solution gas–oil ratio using experimental data

Anti-microbial, anti-diabetic and anti-quorum sensing activity of the essential oil of Dialium guineense Willd. grown in South-West Nigeria

Dialium guineense essential oil possesses various biological and biochemical activities. The present study is based on determination of antimicrobial, anti-diabetic, anti-cholinesterase, anti-biofim, anti-antibiotic resistance modifying activities and anti-quorum sensing potential of essential oil. Chemical compounds in essential oil were recognised by retention indices using gas chromatograph-mass spectroscopy (GC-MS). A total of 45 compounds were present in the essential oil of which 12 are most active. Essential oil of D. guineense showed highest anti-bacterial activity in the form of zone of inhibition, produced 23 mm zone against Staphylococcus aureus and 15 mm against Escherichia coli. D. guineense oil at various concentrations showed excellent anti-diabetic and anti-cholinesterase activities. Since many active compounds were present in D. guineense oil so authors of this study planned to observe effect of D. guineense oil on quorum sensing regulated virulence factors and thus bio-film formation in pathogens Essential oil reduced bio-film formation considerably at all concentrations against E. coli, Staphylococcus aureus and Pseudomonas aeruginosa. Determination of quorum sensing (QS) inhibitory activity was demonstrated by reduction in pyocyanin (73.93%), total protease (68.59%) and chitinase activity (66.18%) in Pseudomonas aeruginosa at 1 mg/mL of D. guineense oil compared to control. Essential oil at all concentrations tested showed synergistic effect. Since essential oil showed anti-microbial, anti-biofilm and quorum sensing regulated anti-pathogenic activities. Based on results mentioned above, it is concluded that bioactive chemicals from D. guineense oil can act as an anti-infective agent by controlling growth, bio-film formation and signalling pathways of pathogenic microbes as well as other diseases.

CAPILLARY PROCESSES DURING FLOODING OF LAYERED-HETEROMOGENEOUS PRODUCTIVE FORMATIONS

The paper presents an analysis of existing laboratory methods for determining capillary pressure functions used in mathematical and computer modeling of the processes of capillary impregnation of low-permeability layers of layered heterogeneous hydrophilic reservoirs during their flooding.It is shown that in existing methods for determining capillary pressure functions in rock samples using capillarimeters and high-speed centrifuges, the factor of the formation of residual oil in the pore space of the rock is not taken into account. At the same time, the processes of displacement of oil by water from productive formations and, in particular, the processes of capillary impregnation of the rock, are characterized by the processes of formation of microvolumes precisely of immobile residual oil in its pore space. Meanwhile, when conducting laboratory studies of rock samples using existing methods, another process is physically reproduced — the process of displacement of water by oil, during which microvolumes of residual water, rather than oil, are formed.This difference in the structure of the oil-water medium leads to a significant difference between the capillary pressure functions determined by traditional methods and the capillary pressure functions that control the distribution of oil and water phases in the pore space of rocks in the processes of displacement of oil from them by water pumped into the reservoir.This difference is especially significant when flooding low-permeability rocks characterized by high capillary pressure values.The work suggests possible approaches to conducting laboratory studies of rock cores that are more consistent with the structural features of the oil-water environment during flooding of productive formations.For the most complete capillary impregnation of low-permeable layers of a layered heterogeneous formation with water from quickly watered high-permeability layers, a method is proposed that consists in the fact that the water pumped into the formation must contain the minimum required amount of oil, ensuring the mobility (connectivity) of the oil phase in the watered high-permeability layers.For this purpose, water from production wells containing a certain amount of residual oil can be used for injection into the reservoir. The economic feasibility of the proposed method should be justified by the results of computer modeling of capillary impregnation processes, taking into account the described features of capillary pressure functions characteristic ofprocesses of oil displacement from productive formations during their waterflooding.

Evaluation of movability of shale oil in organic matter in depletion production by REV-scale simulations

The oil transfer in shale oil formations includes the oil flow in inorganic and organic pores, and the diffusion in the organic matter (OM). A novel triple-continuum model (OM matrix, organic pores, inorganic matrix) is proposed coupling the oil flow (in organic and inorganic pores) and diffusion (in OM matrix). The proposed model is further validated by three-dimensional (3D) numerical simulations. The simulation results show that the proportion of oil production of the absorbed oil from OM matrix in the total shale oil production is small due to the relatively slow diffusion process. However, the diffusion of oil from OM matrix to the organic pores can provide extra energy for the oil expansion in inorganic pores, and thus can greatly increase the oil production in the depletion process. The high OM content can prolong the timespan of oil production. More absorbed oil in OM provides more elastic energy for oil depletion in organic and inorganic pores, and thus leads to higher flow rate in the late period of shale oil production. Smaller size of OM means shorter distance for oil transfer from OM to inorganic matrix, and thus accounts for higher movability of oil in OM.

Insights into the synergistic effect of polylactam kinetic hydrate inhibitor and amino acid via molecular dynamics simulations

Technological innovation is urgently needed to solve the problem of hydrate formation in oil and gas transmission pipelines for the flow assurance guarantee. Typical kinetic hydrate inhibitors for industrial application are the combination of lactam-based polymers with solvent synergists. In this study, a novel non-solvent synergist leucine (Leu) was proposed for improving the kinetic inhibition effect of polyvinyl caprolactam (PVCap). The synergism of PVCap and Leu was investigated via molecular dynamics simulations. Results showed that the 1 wt% PVCap + 2 wt% Leu system can totally inhibit methane hydrate formation within the simulation period, and the combination systems with other concentrations have negligible effects on delaying hydrate nucleation but can significantly slow down the hydrate growth rate. The excellent synergism of PVCap and Leu may be due to the large diffusion coefficient of the molecules in the systems, which provides a high probability for the aggregation of methane molecules and induces the formation of bubbles. In addition, the bubbles can be further stabilized by the amphiphilic PVCap and Leu molecules around it. This study also provides new insights to develop powerful synergists for PVCap, which would be helpful to the design strategy of KHIs with high efficiency.

Elucidating the impact of sanitary waste on the formation of fat, oil and grease deposits in sewer systems

The accumulation of fat, oil and grease (FOG) deposits in sanitary sewer systems is a significant cause of sewer overflows, mainly due to their tendency to adhere to pipe walls. The aim of this study is to (i) develop laboratory-prepared FOG deposits using a mixture of iron (Fe) and aluminium (Al) metal ions, fatty acids, saccharides and cooked oils, in addition to various sanitary waste materials such as paper towels, wipes and pads and (ii) examine the characteristics of these FOG deposits. The goals of this study were to (i) gain a deeper understanding of the impact of sanitary waste on the formation of FOG deposits and (ii) discuss the detailed physiochemical properties of these FOG deposits. The findings revealed that FOG deposits can vary in nature, appearing as either a smooth, paste-like substance or a coarse, semi-solid material, depending on the types of waste present in the sewer. Analysis of the fatty acid profile indicated that the FOG deposits with wipes have the highest viscosity (3.2 × 104 Pa s) and larger composition of smaller chain saturated fatty acids (caprylic acid 0.64%, undecanoic acid 5.61%, lauric acid 4.65%, myristic acid 3.21% and palmitic 8.38%). In contrast, FOG deposits with Fe and Al metal impurities have higher heat resistance and thermal stability (melting point of 125 °C) and have larger composition of long chain fatty acids. Furthermore, FTIR analysis confirmed that these FOG deposits are composed of metallic salts of fatty acids, aligning with samples from sewer lines. Our results suggest that FOG deposit formation involves the aggregation of excess calcium, which compresses free fatty acid micelles, and a saponification reaction between the calcium aggregates and free fatty acids. This research illuminates the complex processes behind FOG deposit formation and their varied characteristics, providing valuable insights into potential strategies for preventing FOG-related sewer blockages.