In recent decades, the global generation of solid oil-containing sludge has increased significantly. Such wastes represent a valuable secondary resource due to high contents of petroleum hydrocarbons, water, and mineral impurities. However, their heterogeneous composition and complex multiphase structure hinder direct utilization and disposal, which makes the selection of appropriate pretreatment methods a critical step in their processing. This article presents a systematic review of pretreatment technologies for solid oil-containing sludge, with a particular focus on grinding, sorting, and beneficiation methods. The advantages and limitations of these methods are analyzed, and promising directions for further technological development are identified. The implementation of integrated pretreatment approaches can facilitate the transition of solid oil-containing sludge from environmentally hazardous waste to valuable secondary resources, thereby promoting resource efficiency and reducing environmental impact.
Fracturability evaluation in naturally fractured reservoirs is essential for optimizing hydraulic fracturing design and enhancing hydrocarbon recovery efficiency. This study proposes a comprehensive fracturability evaluation method based on geology–engineering integration, incorporating key controlling factors including rock brittleness, fracture initiation and propagation capacity, in-situ stress contrast, and natural fracture intensity, with their relative weights quantitatively determined using the Analytic Hierarchy Process (AHP). A major contribution of this work lies in the improved characterization of natural fracture intensity through the integration of seismic interpretation and conventional well-logging data, enabling the construction of a more reliable three-dimensional fracture model. Based on this framework, a three-dimensional fracturability evaluation model is established to quantitatively describe the spatial distribution of reservoir stimulation potential. The method is applied to a typical low-permeability fractured oilfield, where results demonstrate a strong positive correlation between the calculated fracturability index and actual production performance, thereby validating the reliability and applicability of the proposed approach. The findings provide a robust and practical basis for hydraulic fracturing design and optimization in naturally fractured reservoirs, with significant implications for field-scale development planning.
Results are presented for a study of the properties of adsorbents obtained by the sulfonation of wild blackthorn seed shells using sulfuric acid under various conditions. Nitric acid treatment of the sulfonated adsorbent gave an increase in static exchange capacity from 3.2 to 3.7 meq/g. The structural and functional group composition of the adsorbents was characterized by FTIR spectroscopy. The thermal stability, surface morphology, and acid-base surface properties were determined for the most useful samples along with the adsorption capacity and their efficiency in the removal of divalent cations from binary nickel-cadmium and mercury-lead solutions. A pseudo-second-order model was used to accurately describe the adsorption kinetics. The complementary use of the Boyd kinetic model with the Weber-Morris intraparticle diffusion model showed that the adsorption proceeds through a mixed-diffusion mechanism. The introduction of a nitro group into the sulfonated adsorbent improves the adsorption kinetics of the heavy metal cations studied.
In response to the urgent need for energy conservation and consumption reduction in the oil and gas storage and transportation system under the dual carbon goal, this paper aimed to solve the problem of calculation deviation caused by parameter drift in traditional mechanism models under complex working conditions such as equipment aging and environmental variability. Based on the massive SCADA data of an 850 km wax-containing crude oil pipeline, a PSO-CNN-LSTM-Attention combined energy consumption prediction model optimized by the particle swarm algorithm was constructed. The research results showed that this model achieves a 98
In this study, a computational molecular modeling framework was established by integrating force-field-based molecular dynamics simulation, trajectory analysis algorithms, mean square displacement calculation, radial distribution function analysis, and spatial concentration profiling. These computational algorithms were used to quantitatively characterize the diffusion behavior, aggregation tendency, interaction distance, and microstructural evolution of heavy oil components in ionic liquid–solvent systems. The interaction mechanism between [Emmim][NTf2] ionic liquid and five organic solvents (acetone, toluene, methylcyclohexane, carbon tetrachloride, ethyl acetate) and four components of heavy oil (saturated, aromatic, colloidal, and asphaltene) was studied by molecular dynamics simulation. The dynamic evolution of molecular diffusion behavior, interaction intensity and microstructure in different systems was revealed. The results show that the saturation fraction has the strongest diffusion ability due to its simple structure and small molecular weight. The addition of ionic liquid [Emmim][NTf2] significantly changed the interaction mode of the system: in the saturated subsystem, its diffusion resistance was the smallest; In the aromatic subsystem, the ϖ-cationic action inhibits its movement. In colloidal and asphaltene systems, strong polar interactions lead to hindered diffusion. In addition, solvent properties have an important influence on system behavior: polar solvents bind to components by dipolar action, while non-polar solvents rely on van der Waals forces and π-π accumulation. The energy and temperature equilibrium analysis showed that all systems reached a steady state within 2000 ps, which verified the reliability of the simulation. This study provides a theoretical basis for the application of ionic liquids in heavy oil modification and solvent extraction, reveals the interaction mechanism at the molecular scale, and has guiding significance for optimizing process conditions.
In this work, we present a synthesis of a catalyst derived from phosphomolybdenum vanadic acid supported on cesium‑ion‑promoted KSKG silica gel and studied its morphology. X‑ray fluorescence analysis, cryoporometry, and thermogravimetric analysis were used to study the composition, textural characteristics, and thermal stability of this system. We found homogeneous distribution of the active phase, decreased specific surface area due to pore occupation, and the formation of a heat‑resistant structure after calcination at 400°C.
The effect of the nature of the acid residue in polyglycerol esters on their rheological properties was studied. Samples of such esters were synthesized with aliphatic, aromatic, and hydroxyl-containing acid residues. The replacement of the polyglycerol hydroxyl groups by ester fragments leads to a change in the system of intermolecular interactions. The nature and extent of this change are functions of the structure of the acid residue. Our results demonstrate the possibility of adjusting the rheological properties of polyglycerol esters in a broad range by variation of the structure of the acid residue, which holds interest in the development of lubricants with targeted temperature-viscosity performance.
To enhance the signal quality and data transmission rate of continuous pressure pulse generators in Measurement While Drilling (MWD) systems, a three-dimensional transient numerical model was established using the shear stress transport SST k-ρο turbulence model and a stage-wise solving strategy. Its reliability was validated via indoor water circulation bench tests, with an amplitude error of approximately 3
As a critical reservoir characteristic parameter, the pore-throat property exerts a substantial influence on reservoir performance and hydrocarbon flow potential. Moreover, the characterization of this parameter remains one of the core challenges and persistent hurdles in tight sandstone reservoir research, holding profound implications for the efficient development of tight hydrocarbon reservoirs. In this study, typical samples were collected from the Chang 6 tight reservoir of the Jiyuan Oilfield in the Ordos Basin. High-pressure mercury injection (HPMI) and nuclear magnetic resonance (NMR) techniques were employed to characterize the pore-throat properties of the reservoir. Furthermore, the relationship between pore-throat structure and movable fluid parameters was investigated. The results indicate that, based on experimental data and the morphological features of the corresponding curves, reservoir pore types can be classified into four distinct categories. The physical properties of the reservoir progressively deteriorate from Category I to Category IV, while the mercury injection pressure exhibits a gradual upward trend. The T2 spectra are predominantly bimodal in shape, and the main developed saturation ranges for Categories II and III are 48.77–51.14
CO2 flooding is a well-established and widely adopted Enhanced Oil Recovery (EOR) technology. However, most terrestrial sedimentary reservoirs in China exhibit poor physical properties, significant heterogeneity, and high crude oil density. Large-scale implementation of CO2 flooding in these reservoirs requires overcoming technical challenges, including achieving phase miscibility and expanding the swept volume, to enhance recovery efficiency. In 2012, Jilin Oilfield designated the Hei-79 North Block as a test area for small well spacing CO2 flooding research. Over more than a decade, this area has accumulated 1.3 hydrocarbon pore volumes (HCPV) of gas injection. The complete development cycle of CO2 flooding, from early to late stages, has been implemented. The total amount of sequestered CO2 exceeds 4.2·104 tons, and the estimated recovery rate is over 25
Volumetric stimulation in tight sandstone–shale reservoirs relies on hydraulic fractures that vertically connect multiple thin gas-bearing layers. Predicting fracture propagation in such thinly interbedded formations is difficult because it is jointly governed by mineralogical heterogeneity, bedding-related weak planes, elastic contrast, and in-situ stress variation. Thus, the Xujiahe Formation reservoir in Block X, southern Sichuan, was characterized by integrating whole-rock X-ray diffraction, triaxial mechanical testing, differential-strain in-situ stress measurements, and paleomagnetic stress-orientation analysis. The experimentally constrained parameters were incorporated into a three-dimensional discrete element model to examine the effects of injection rate and fluid viscosity on cross-layer fracture growth. Results show that sandstone predominantly fails in tensile planar fractures, whereas shale exhibits shear-dominated composite failure along bedding-related weak planes. Although the modulus contrast between the two lithologies exceeds 5 GPa, the interlayer stress difference is only 1.21 MPa, which weakens interface containment and renders fracture growth highly sensitive to fluid dynamics. Low-viscosity, low-rate injection promotes bedding-parallel shear slip; higher viscosity or injection rate elevates fracture-tip pressure and enhances tensile cross-layer extension. A low-viscosity, high-injection-rate strategy is therefore recommended to balance vertical penetration, microfracture activation, and volumetric stimulation. Considering the 101.4 mm wellbore diameter and the equipment pressure limitation, a fracturing fluid viscosity of 3–9 mPa·s and an injection rate of 12 m3/min are recommended for fracturing operation.
Inhibiting the surface hydration of shale is one of the key technologies for maintaining wellbore stability, but current research is not sufficient, especially given the lack of in-depth exploration of the correlation between the molecular structure of an inhibitor and its surface hydration inhibition performance. In this study, a low-molecular-weight alkyl diamine inhibitor, WSI, was designed and synthesized. The experimental results showed that after adding WSI, the isothermal adsorption water content of sodium montmorillonite decreased from 0.1104 to 0.0311 g/g, and the substrate spacing increased from1.01 nm to 1.34 nm, the DTG curve only shows a single low-temperature peak. Moreover, the linear expansion height of sodium montmorillonite decreased from 8.1 mm to 5.2 mm, and the rolling recovery rate increased from 35.24
To clarify the oil and gas resource potential of the Mahaidong area in the Qaidam Basin and identify priorities for subsequent exploration deployment, this study systematically reviews the regional tectonic background, stratigraphic framework, and sedimentary characteristics. On this basis, key accumulation elements, including hydrocarbon generation, reservoirs, caprocks, and traps, are comprehensively analyzed, and an integrated resource potential evaluation method is established, combining geological analysis, geophysical identification, and geochemical verification. Recent public exploration progress is also incorporated to summarize the evaluation results, providing a basis for further advancement of oil and gas resource development in the Mahaidong area. The results indicate that the Mahaidong area is controlled by multi-stage tectonic superposition and reworking in the eastern segment of the northern margin of the Qaidam Basin. Hydrocarbon accumulation conditions are generally favorable, and a relatively clear source-reservoir-caprock-trap configuration has been formed. The Paleogene Lulehe Formation has achieved reserve confirmation, showing strong potential for near-term rolling exploration. Although Paleogene tight sandstones display hydrocarbon shows, sweet-spot evaluation remains the key issue due to reservoir densification and strong heterogeneity. The Proterozoic buried-hill basement also shows promising potential as a replacement exploration target, indicating that exploration targets in the area are expanding toward multiple strata and multiple target types. It is concluded that the Mahaidong area is overall a medium-to-high potential zone with locally high-potential targets, and future exploration should adopt refined deployment by stratigraphic interval, structural belt, and target type.
The paper presents a comprehensive analysis of the effect of aviation oils on the operational characteristics of gas turbine engines. Based on the analysis of technical specifications, it is shown that the introduction of synthetic oils with an extended upper temperature range and improved tribological properties enhances engine reliability and reduces operating costs. Special attention is paid to the role of modern oils in the implementation of sustainable aviation development strategies.
This article examines promising approaches to the design of refinery process schemes based on the application of Big Data analysis methods and artificial intelligence (AI) models. A methodology is proposed in which, based on the physicochemical characteristics of the initial hydrocarbon feedstock, trained neural network models generate preliminary versions of the plant’s technological configuration, optimized in accordance with the specified target indicators. The necessity of taxonomic classification of all types of crude oil according to their physicochemical parameters is substantiated, which makes it possible to neutralize the problem of incompleteness or incorrectness of initial data, form unified process schemes for groups of crude oils with similar characteristics, and select invariant processing configurations that do not require reconfiguration of production infrastructure. Special attention is paid to the ability of AI models, based on implicit mathematical dependencies identified during training, to carry out predictive calculation of crude oil properties, its fractions, and target products, even if these properties were not included in the initial vector of input parameters.
To improve the operating efficiency and development performance of artificial lift systems in the middle and late stages of oilfield production, this study carried out a multi-parameter optimization analysis for artificial lift operations. After comparing several commonly used intelligent optimization methods, including Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Simulated Annealing (SA), and Ant Colony Optimization (ACO), PSO was selected as the main optimization tool. In this study, a multi-parameter optimization model was built with daily liquid production, system efficiency and unit energy consumption as the main evaluation indexes. Based on field conditions, pump setting depth, stroke length, pumping speed and bottomhole flowing pressure were selected for coordinated optimization. The results indicate that the optimized scheme achieved a good application effect. After optimization, the daily liquid production of the case well increased from 24.6 m3/d to 28.9 m3/d, system efficiency increased from 45.2
The current state of research on the applicability of the simulated distillation method for various petroleum refining products was examined. The fractional composition of middle distillates, vacuum fractions of various origin, and commerical diesel fuel samples was compared. The results obtained by the ASTM D86 and ASTM D2887 methods after correction proved comparable and do not require further correction for the composition of aromatic hydrocarbons. In comparing the results obtained using the ASTM D1160 and ASTM D7169 methods, the disparities between the values obtained depend on the origin of the samples.
To solve the problem of seismic identification of thin interbedded sand bodies in shallow water delta front, taking the thin sand layer of shallow water delta front in Gaotaizi oil layer in Taikang area of Songliao Basin as an example, a comprehensive prediction method system of sand bodies based on multi-attribute fusion of seismic waveform indication inversion and seismic sedimentology is innovatively constructed. By integrating seismic waveform indication simulation inversion technology and seismic sedimentology stratigraphic slice analysis technology, the synergistic analysis of sedimentary microfacies and thin reservoir quantitative characterization is systematically carried out. Based on the theoretical framework of seismic sedimentology, the root mean square amplitude attribute slice, frequency division attribute analysis, and RGB multi-attribute fusion technology can effectively reveal the sedimentary evolution law in the transgressive-regressive cycle, and accurately describe the plane distribution characteristics of channel sand microfacies in delta front subfacies, including the extension direction, migration path and distance of sand body. Under the constraint of sedimentary microfacies, the seismic waveform indication inversion technology significantly improves the vertical resolution (up to 2m) and lateral continuity prediction accuracy of thin sand bodies by establishing the nonlinear mapping relationship between logging curves and seismic waveform structure characteristics. The coincidence rate between inversion results and verification wells is 83
This study successfully synthesised a novel foaming agent, WSPJ-1, using lauric acid, low-molecular-weight organic amines, n-butanol, and sodium 2-acrylamido-2-methylpropane sulfonate as primary raw materials. Building upon this, a novel corrosion inhibitor-foam displacement agent suitable for foam drainage gas production in tight sandstone gas fields was developed through compounding with highly efficient corrosion inhibitors and foam stabilisers. Laboratory evaluations of the prepared corrosion inhibitor-foam drainage agent focused on its thermal stability, salt tolerance, contamination resistance, and corrosion inhibition performance. Experimental results indicate that within a temperature range of 30–120°C and salinity levels of 0–106,500 mg/L, the corrosion inhibitor foam drainage agent maintains excellent foam stability, demonstrating robust thermal and saline resistance. Even at methanol or condensate oil volumes reaching 30
Traditional methods for the extraction of lithium involve high energy expenditures and considerable environmental damage. In this context, the development of efficient and environmentally-safe methods for lithium recovery is of particular importance. In this paper, we consider the possibility of creating cellulose-based adsorbents with various types of functional groups and evaluate their structure, adsorption capacity, and regenerability. The adsorption efficiency of such materials toward lithium ions is a function of the combined effect of the density, nature, and accessibility of the ionogenic centers, which, in turn, is governed by the morphology and porous structure under dynamic contact conditions. This research is aimed to further the use of plant-derived cellulose materials in the treatment to extract lithium from produced water.
