Oil Field Research Articles

Experimental estimation of specific surface area of bazhenov oil shale and factors controlling its increase

The almost complete depletion of easily recoverable oil reserves and intensive development of reserves with complex geological structures characterize the development of oil fields today. Due to the non-standard geological structure of such reservoirs, operators face multiple challenges that do not appear with the production of easily recoverable oil. A vivid example is oil field K, which contains low-viscosity oil and has a well-permeable terrigenous pore reservoir. Initial data obtained during exploratory drilling and trial production allowed optimistic forecasts of achieving an oil recovery factor (ORF) of 0.364. However, features of the geological structure hindered the achievement of this recovery target. This paper studies explore potential strategies for increasing oil recovery in the AB 1-2 area of oil field K. The aim of this paper is to identify reasons for the low oil recovery at oil field K and to develop recommendations for methods, which could enhance recovery and increase the oil recovery factor. The authors created synthetic hydrodynamic model of the AB1-2 oil object. They also performed multivariate calculations to analyze the structure of oil saturation and clarify the causes of low oil recovery. The authors reviewed six development strategies for the AB 1-2 object model: traditional water flooding, cyclic water flooding with injection wells, cyclic water flooding with injection and production wells, and polymer flooding. The oil recovery factor values obtained in these scenarios ranged from 0,238 to 0,265. Based on the results of this study, the authors recommend to use a combination of cyclic and polymer flooding.

Abstract It is a new field to improve oil recovery by reducing the viscosity of thin oil in low permeability reservoir, which has a breakthrough significance for the development of low permeability oilfield. But, the oil increase effect of viscosity reducer (VR) solution on thin oil lacks the experimental data and theory support. The viscosity of ground degassed crude oil from the thin oil reservoir is 26.4 mPa s at 72°C. The feasibility of the application of VR solution in thin oil reservoir was analyzed through the experiment and test of viscosity reducing ability, percolation capacity, and displacement effect of VR solution. The oil–water ratio is 5:5, the VR concentration ( C VR ) of oil–water dispersion (OWD) solution is 0.1%, and the viscosity reduction rate of VR solution reaches 92.4%. The maximum instantaneous injection pressure ( P max ) of the VR solution injected with the C VR of 0.1% is the lowest, which is 6.60 MPa, the P max decreases by 0.83 MPa than the P max in the basic water flooding experiment, the injection pressure in stable stage ( P min ) decreases by 0.80 MPa. When the bound water saturation ( s wi ) ({s}_{\text{wi}}) of core is 41.1%, the VR solution is directly injected before water flooding, from the initial stage of water flooding, the water content ( f w ) ({f}_{\text{w}}) at the producing end tends to rise more slowly than that at the producing end of water flooding, the final recovery rate ( E R,final ) is the highest, 42.5%, the residual oil saturation is only 33.9%. The decrease in P max and the increase in E R,final indicate that the injection of VR solution can improve the percolation capacity of crude oil, and the method of reducing thin oil viscosity can be applied to the development of special permeable thin oil fields.

The depletion of low-viscosity and light oils forces producers to increase the development of heavy and highly viscous oils. However, traditional steady waterflooding often prove ineffective for reservoirs containing such oils. Therefore, there is a need to find inexpensive and efficient methods to improve oil recovery from these reservoirs. Cyclic waterflooding method has two main benefits: almost zero implementation cost and ease of application. This method has been widely utilized since the late 1950s in oil fields globally, including regions in Russia (Western Siberia, the Republic of Tatarstan, the Samara region, and Perm Territory), China, the United States, and the Czech Republic. This study examines the effectiveness of two variants of cyclic waterflooding for developing reservoirs with oils of different viscosities. The aim of this paper is to understand how oil viscosity affects oil saturation distribution within the reservoir and the overall efficiency of cyclic waterflooding. The results of the study include an analysis of oil viscosity effects on development strategies for a two-dimensional synthetic reservoir model. These results are crucial for selecting suitable sites for cyclic waterflooding in specific oil fields. The study shows that combining cyclic water injection with injection wells and periodic forced liquid withdrawal from production wells is the most effective modification of cyclic waterflooding. This modification facilitates the efficient development of reservoirs containing highly viscous oil.

Developing fields with a large gas cap and a volumetric oil rim requires continuous improvement of oil displacement technologies. This necessity arises from the heterogeneity of reservoir properties and, in some cases, unfavorable phase mobility ratios within the reservoir. Without timely adjustments in reservoir management strategies, there is a considerable risk of reduced sweep efficiency and displacement, which can lead to failure to achieve the design levels of inventory production. In addition to managing oil recovery in gas-supported reservoirs, the effective financial and technological utilization of associated petroleum gas is also critical. Choosing technologies that simultaneously increase oil recovery and ensure the planned use of APG is currently a priority for oil and gas companies. This paper reviews gas and gas-chemical methods for enchancig oil recovery and assesses the potential effectiveness of these methods in the context of the Novoportovsky oil and gas condensate field.

This study examines the productive horizon of Miocene deposits in an oil and gas field in the Pannonian Basin (Republic of Serbia). To clarify the features of the geological structure and improve the efficiency of upcoming development of new productive areas while increasing oil recovery from existing parts of the field, the authors of this paper conducted a detailed analysis and synthesis of core data, seismic work materials, testing and the dynamics of production wells. Through conducted studies, the authors detailed the geological features of the field, updated the conceptual model, and proposed additional methods for developing the identified oil and gas reservoirs. Researches also rebuilt the geological model, adjusted the placement of the project well stock and developed a set of geological and technical measures to enhance oil recovery. Furthermore, they forecasted of development indicators. The study identified features of the field’s geological structure that suggest a “mosaic” distribution of filtration and capacitive properties within the established hydrocarbon reservoirs. The localized character of the distribution of productivity and variability of field parameters that influence the success of discovery, efficiency of involvement and development of such hydrocarbon deposits confirms the fractal properties of the geological environment. In conclusion, the authors highlighted the necessity of studying and applying the fractal properties of geological objects during oil and gas exploration.

Phytotoxicity and accumulation of PFHxS in Australian native grasses of arid regions: implications for ecological risk assessment.

Characterization of the mulberry field antibiotic resistome and mobilome across China.

Optimizing harvest timing in rapeseed (Brassica napus L.): Balancing oil yield, metabolic quality, and field efficiency

Deployment-related toxic exposures, mental health problems, and suicide outcomes among Gulf War era U.S. veterans.

A joint Gaussian process model of geochemistry, geophysics, and temperature for groundwater TDS in the San Ardo Oil Field, California, USA

Effects of petroleum contamination on soil metal(loid)s and microbial communities.

Substrates and pathways preference of two novel species of Rhodococcus for aromatic compounds degradation.

An evaluation of the relationship between fingering flow fraction and water flux in natural field soil

Biochar remodeled rhizosphere microbial community structure and function to alleviate sugar beet under fomesafen phytotoxicity.

Cyanobacteria, as vital photosynthetic microorganisms in soil ecosystems, contribute to soil stabilization, nutrient cycling, and water balance. They also produce bioactive compounds such as lipopeptides, carotenoids, and phytohormones. This study explored the plant growth-promoting potential of cyanobacterial strains isolated from native paddy field soils. A polyphasic approach, combining 16S rRNA gene sequencing, phylogenetic analysis, and morphological assessments was used to characterize the isolates. Microscopy revealed distinct traits, including barrel-shaped cells, intercalary and terminal heterocytes, solitary akinetes adjacent to heterocytes, and proakinetes occurring near heterocytes. The strain also displayed a fascicular thylakoid arrangement and contained distinct nutrient storage granules. Phylogenetic analysis placed the isolate in close relation to Neowollea manoromensis. The strain produced an auxin-like compound, identified as indole-3-acetic acid (IAA), under various tryptophan concentrations. IAA was confirmed through TLC, FT-IR, and HPLC. In vitro experiments with paddy seeds treated with cyanobacterial extract showed 95.55% germination, with significant root elongation (11.27 ± 0.09 cm) and shoot growth (6.46 ± 0.050 cm) by day 12. Chlorophyll content (3.18 μg/mL), fresh weight (0.69 ± 0.09 g), and dry weight (0.08 ± 0.00 g) also increased. These results underline the auxin-producing potential of the cyanobacterium and its effectiveness in enhancing seed germination and plant growth, offering a sustainable strategy for improving paddy cultivation.

This study assesses the risks, opportunities, and economic implications of dual-purpose carbon dioxide (CO₂) injection for Enhanced Oil Recovery (EOR) and long-term carbon storage in the U.S. energy sector. Through a comprehensive review of Carbon Capture Utilization and Sequestration (CCUS) technologies, policy frameworks, and case studies such as the Petra Nova and Illinois Industrial Carbon Capture projects, the analysis evaluates how this approach can enhance energy security, stimulate economic growth, and support climate goals. Key findings reveal that dual-purpose CO₂ injection extends the lifespan of oil fields, reduces net carbon emissions through permanent sequestration, and generates economic benefits via job creation and revenue generation. However, its success depends on overcoming technical challenges (e.g., leakage risks), financial barriers (e.g., high capital costs), and regulatory uncertainties. Policy incentives like the 45Q tax credit and advancements in monitoring technologies are critical for scaling deployment. The study concludes that dual-purpose CO₂ injection offers a transitional pathway to balance fossil fuel dependency with decarbonization, contingent on robust policy support, stakeholder engagement, and technological innovation.

Background: The primary objective of the current study is to evaluate the environmental risks and heavy metal contamination in irrigation water, soil and crops cultivated in agricultural fields near certain oil fields. Methods: Atomic absorption spectrometry was used to test and analyze water, soil and plant samples for Cadmium (Cd), Chromium (Cr), Lead (Pb), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni) and Zinc (Zn). Result: The samples extremely low concentrations of Cd, Cr and Pb were found in the laboratory, indicating that the local environment is free of these heavy metal contaminants. Fe was the dominant pollutant, exhibiting severely high concentrations, soil at the Amara site (BS) contained Fe at 85,369.62 mg/kg, far exceeding the WHO safety limit. Mn also showed significant contamination, with crop levels reaching 821.97 mg/kg, well above recommended guidelines. In contrast, concentrations of Cu (13.21-83.15 mg/kg), Ni (3.44-86.26 mg/kg) and Zn (52.88-174.40 mg/kg) in water, soil and crop samples were found to be within the permissible limits according to international standards. This stark divergence confirms that the multi-element contamination, as identified by the composite index, is primarily driven by Fe and Mn. The significant bioaccumulation of these metals in crops Fe at 645-673 mg/kg versus a 50-300 mg/kg standard, highlights a critical pathway from soil to the food chain. These findings unequivocally point to anthropogenic activities from the oil fields as the source of pollution, posing a direct threat to agricultural safety and potential human health risks.

Abstract The stable operation of the pumping units is crucial to ensuring the efficient exploitation of the oil fields. Given the pumping units operating in extreme geological environments with complex physical interactions , it is susceptible to many common faults including insufficient liquid supply, gas lock, and valve leakage, which directly threaten production safety. Currently, although many efforts are focused on improving the effectiveness and interpretability of models, the ultimate goal corresponding to practical applications is the desire to reduce cost and enhance efficiency. In order to solve this challenge, a novel deep neural network named DiSpecNet is proposed, which is an ultralightweight diagnostic model tailored for the efficient classification of indicator diagrams. The proposed DiSpecNet excels in providing high operational speed, while maintaining top-tier accuracy. The architecture is built upon three lightweight blocks proposed to extract and fuse spatial dimensions such as width, height, channel, and frequency domain from layer-level feature maps. These blocks effectively harness and integrate multi-feature spatial information. To further enhance its performance, a specialized block loss is employed for real-time feature utilization. Experiments based on two datasets and eleven state-of-the-art baseline methods showed that DiSpecNet exhibits superior performance in terms of accuracy and efficiency. Experimental results demonstrate that DiSpecNet achieves 93.41% accuracy ( ↑ 1.26% vs EfficientNet) and 93.48% Kappa ( ↑ 2.68% vs EfficientNet) on extreme dataset, while reducing Parameters costs by 89% (0.44 M) and model size by 79% (3.19 MB). To ensure the reproducibility of the experiment, the code of this study has been prepared for public release. Our code will be available at https://github.com/JEFfersusu/DiSpecNet .

The paper discusses tests of an electric capacitance sensor designed and built to measure gas fraction in a reservoir fluid flow. These tests were conducted under conditions typical for oil field testing and productivity monitoring. In such an application, the electrical permittivity of the liquid and gas components is of the same order of magnitude, which poses a significant challenge in capacitance metering of the phase content. The studied two-electrode capacitance sensor is a novel design. It uses a commercial, high-resolution ΔΣ capacitance-to-digital converter. The sensor was experimentally tested on the flow of reser-voir fluid (from Lubiatów-Międzychód-Grotów field in Poland) heated to 40–50°C to reproduce field conditions during actual gas and oil extraction. The gas fraction in the reservoir fluid was generated by the injection of air or methane bubbles. Fluid velocities during the testing ranged from 1 to 3.1 m/s, and the void fraction reached 4.4%. After calibration, the examined capacitance sensor was able to detect a void fraction as low as 1%. The measured capacitance differences due to gas content were dependent on the spatial distribution of voids in the inter-electrode space. This effect was confirmed by photographs of the flow patterns and numerical simulations of the electric field distributions.