Search Results (393)

Multi-trace amplitude variation with angle inversion (MAVAI) is a vital tool for estimating the physical parameters of subsurface media, and it plays an important role in oil and gas exploration. However, the existing MAVAI method relies on the Kronecker product to construct an extremely large-scale inverse problem, and its computational inefficiency limits its widespread application. Furthermore, regarding regularization constraints, the existing MAVAI method only considers the smoothness of the inversion parameters, which leads to ambiguous formation boundaries and hinders accurate identification for complex reservoirs. To address these issues, a compressed MAVAI method with elastic half-norm regularization is proposed. Specifically, we first developed a compressed MAVAI (CMAVAI) framework that uses compressed measurements of seismic data and reference models in a sparse domain to construct the CMAVAI objective function, thereby reducing the scale of the inversion problem and improving inversion efficiency. Subsequently, the elastic half-norm is introduced into the CMAVAI framework as a regularization constraint for reservoir parameter estimation. Since the elastic half-norm can simultaneously characterize both the smoothness and blocky features of the subsurface medium, it effectively improves inversion accuracy compared to the MAVAI method. Finally, the performance of the proposed method is evaluated using a theoretical model and field data. The results demonstrate that, compared with the traditional MAVAI algorithm, the CMAVAI framework can effectively improve inversion efficiency while maintaining inversion accuracy. Moreover, the CMAVAI method regularized by the elastic half-norm can improve the accuracy of inversion parameters while retaining the high prediction efficiency of the CMAVAI framework. Full article

River-channel washout is one of the common geological hazards threatening the safety of long-distance oil and gas pipelines, particularly under storm-flood conditions, when pipeline sections crossing rivers and gullies are more susceptible to damage. Existing assessment methods for river-channel washout are effective for single river cross-sections or post-disaster field investigations; however, their application remains limited when dealing with long-distance pipeline systems characterized by numerous river- and gully-crossing sections and large spatial variability in upstream catchment conditions. To address this issue, this study investigates storm-flood discharge and scour-depth calculation methods suitable for river- and gully-crossing sections of long-distance oil and gas pipelines, and establishes a quantitative evaluation index system that considers river-channel washout susceptibility, pipeline vulnerability, and pipeline failure consequences. Based on investigation results of river-channel washout hazards along multiple pipeline systems, including the Zhongxian–Yichang section of the Zhongwu Pipeline, the Hubei–Hunan section of the Lanzhou–Zhengzhou–Changsha Pipeline, and the Phase I Jiangxi Natural Gas Pipeline Network, the hazard characteristics and influencing factors of river-channel washout affecting long-distance oil and gas pipelines are analyzed and summarized. The proposed method was applied to 19 river- and gully-crossing pipeline sections in the Phase I Jiangxi Natural Gas Pipeline Network under different rainfall intensities. The results show that, under light-to-moderate rainfall conditions, 15 sites were classified as relatively low risk and 4 sites as medium risk. Under both the 50-year and 100-year return-period rainstorm scenarios, 12 sites were classified as relatively low risk, 6 sites as medium risk, and 1 site as relatively high risk. The results also indicate that the risk probability of some sites increases with increasing rainfall intensity. Among them, Site No. 19 shows the highest risk probability, increasing from 0.0997 under light-to-moderate rainfall conditions to 0.1474 and 0.1488 under the 50-year and 100-year return-period rainstorm scenarios, respectively. The proposed method can provide a reference for meteorological risk assessment of river-channel washout hazards along long-distance oil and gas pipelines. Full article

Chamaecyparis obtusa is a valuable conifer species, prized for its high-quality timber and bioactive essential oils. However, commercial micropropagation is challenging due to its resistance to vegetative propagation. This study aimed to develop an efficient in vitro plant regeneration system using leaf explants and to profile the metabolic changes during organogenesis. Leaf explants from one-year-old in vitro-grown plantlets were cultured on media with various plant growth regulators (PGRs) to optimize callus induction, shoot multiplication, and rooting. Secondary metabolites were systematically analyzed throughout the developmental stages: explant, callus, regenerated shoot, and rooted plantlet. The most effective shoot regeneration, leading to whole plantlets, was achieved on a medium supplemented with 1.0 mg/L 2,4-dichlorophenoxyacetic acid and 2.0 mg/L thidiazuron. Metabolic profiling revealed significant stage-specific biochemical transitions. High-Performance Liquid Chromatography (HPLC) precisely quantified individual phenolics, resolving cross-reactivity issues seen in total flavonoid colorimetric assays. Gas Chromatography-Mass Spectrometry (GC-MS) also identified substantial shifts in volatile terpenoid biosynthesis during shoot morphogenesis. This integrated protocol provides a reliable platform for mass propagation of C. obtusa and offers fundamental insights into the metabolic dynamics of in vitro development, with significant potential for future horticultural and biotechnological applications. Full article

With the gradual decline in conventional oil and gas production growth, unconventional natural gas has become a strategic alternative for hydrocarbon supply. Coal-rock gas (CRG) represents a deep unconventional gas resource with huge potential. Major exploration breakthroughs of CRG have been achieved in China, while systematic research targeting CRG as an independent gas reservoir is still lacking internationally. After effective commercial development, CRG serves as an important supplementary energy source for the domestic natural gas supply. Existing logging evaluation methods exhibit notable deficiencies, as porosity is typically estimated by fitting well logging data or proximate analysis data, resulting in limited accuracy. To address the lack of a dedicated logging volumetric model, ambiguous coal-matrix framework parameters, and substantial porosity calculation errors in deep CRG reservoirs, this study investigates the medium–high rank No. 8 coal seam of the Benxi Formation in the central-eastern Ordos Basin. From an oil and gas reservoir logging evaluation perspective, multi-scale experiments were conducted to systematically characterize the material composition and microscopic characteristics of the coal rock. From the perspective of oil and gas reservoir logging evaluation, a three-component logging volumetric model, consisting of a coal matrix, inorganic minerals, and pore fluids, was constructed, and the corresponding coal-matrix framework parameters were calibrated. The results demonstrate that coal rock is an organic–inorganic composite system, with organic macerals dominated by vitrinite (averaging 59.1%) and inertinite (27.1%). The sum of fixed carbon and volatiles exhibits strong correlations with total organic carbon (TOC) and micro-CT-derived coal-matrix content, yielding determination coefficients of 0.99 and 0.95, respectively, which validates the reliability of the multi-scale quantitative composition characterization. The coal-matrix framework parameters are non-constant: density ranges from 1.08 to 1.56 g·cm⁻³, acoustic slowness from 281 to 425 μs·m⁻¹, and compensated neutron from 39% to 79%. Borehole enlargement severely affects compensated density and neutron logs but has negligible interference with acoustic slowness. Notably, inertinite content shows a significant negative correlation with the acoustic-slowness framework response (R² = 0.80), indicating that structurally dense inertinite is a key intrinsic factor controlling the elastic response of the coal matrix. For porosity evaluation, a dual-variable framework model is proposed. The core novelty of this method is that it simultaneously incorporates variations in inorganic mineral content and differences in inertinite proportion within organic components as dynamic framework constraints, breaking through the limitation of the conventional constant-matrix assumption. The acoustic-slowness-based model achieves an average relative error of merely 7.1%, effectively resolving the large errors inherent in conventional fitting methods. The dedicated coal-rock logging evaluation system established in this study overcomes the limitations of fixed framework models, offers a scientific basis for fine-scale interpretation and resource assessment of deep CRG reservoirs, and provides a valuable reference for evaluating analogous reservoirs. Full article

The Songliao Basin is an important Meso-Cenozoic terrestrial petroliferous basin in China. The hydrocarbon source rocks of the Upper Cretaceous Qingshankou Formation in the Central Depression possess favorable oil-generating conditions and huge hydrocarbon resource potential. This paper systematically analyzes the geochemical characteristics and simulates the thermal evolution history of Upper Cretaceous source rocks in the study area. The results show that the total organic carbon (TOC) content of Qingshankou Formation source rocks reaches up to 4.6925%. Organic matter is predominantly Type I and Type II₁, representing high-quality hydrocarbon source rocks. Thermal history simulation reveals two evolutionary stages: rapid temperature rise from the Early Cretaceous to the Late Cretaceous, and gradual cooling from the Late Cretaceous to the present day. Continuous temperature increase occurred during the depositional period of the Qingshankou to Mingshui Formations, with the maximum paleotemperature up to 180 °C. Paleotemperature has gradually decreased since the late depositional stage of the Mingshui Formation. The average TOC content of the 1st Member of Qingshankou Formation is 3.88%, classified as high-quality source rock. It reached the hydrocarbon generation threshold at approximately 82 Ma and is currently at the high-mature stage. The average TOC content of the 2nd and 3rd Members is 1.31%, also high-quality source rock. These strata entered the hydrocarbon generation threshold at about 80 Ma with relatively low vitrinite reflectance (Ro), belonging to the medium-mature and high-mature stage. Since the deposition of the Qingshankou Formation, the major hydrocarbon generation period of Cretaceous source rocks in the Central Depression ranged from 75 Ma to 80 Ma. The maximum oil generation rate is 28 mg/(g·TOC·Ma), and the cumulative oil generation capacity peaks at 220 mg/(g·TOC). The maximum gas generation rate reaches 5.5 mg/(g·TOC·Ma), with a maximum cumulative gas yield of 40 mg/(g·TOC). Full article

Ukraine’s energy strategy under martial law necessitates decentralized local energy systems to counter electricity shortages and systemic infrastructure failures. The study develops and validates an optimization model for designing the architecture of decentralized “energy islands” based on circular bioenergy models for agricultural waste use. Empirical verification was conducted using data from the Vinnytsia region in Ukraine. The model accounts for a multi-level structure that separates micro/small generation (0.1–2.0 MW) from medium generation (1–20 MW) based on the logistical radius for raw material collection. The model incorporated the Value of Lost Load (VLL), enabling the monetization of avoided socio-economic losses from energy shortages. In addition, the coefficient of energy island sustainability (I_sred) was introduced to quantitatively assess the effectiveness of investments in terms of replacing external resources. The modeling revealed the nonlinear nature of the total cost function, enabling us to determine an optimal energy-autonomy range of 40% to 50% for communities. At this threshold, the total construction and logistics costs are minimized. The potential socio-economic losses from blackouts are effectively mitigated, as confirmed by the calculated sustainability coefficient (I_sred), which ranges from 0.78 to 0.94 across the studied communities. The resource potential assessment confirms that the region’s total potential is approaching 30 million tons of oil equivalent, driven by solid biofuels, agricultural residues, and energy crops (miscanthus, switchgrass). The classification of biomass supply chains shows that exceeding the transportation radius by more than 70 km at the meso level, or deviating from the optimal logistics lever by 20%, reduces the profitability of projects below the critical limit of 15%, which justifies strict localization within raw-material clusters. This enables local communities to eliminate natural gas consumption, reduce energy supply operating costs by 15%, and ensure the autonomous and stable operation of critical infrastructure facilities during prolonged disruptions to the national power grid. Full article

Hydrotreated vegetable oil (HVO) is considered a promising drop-in alternative to conventional diesel fuel for reducing greenhouse gas emissions in road freight transport. However, empirical evidence on its performance under real-world operating conditions remains limited. This is particularly true for complex logistics systems such as agricultural transport. This study assesses the effect of neat HVO (HVO100) on fuel consumption using high-resolution vehicle operational data collected from three heavy-duty trucks during a full-scale sugar beet logistics campaign in Germany. Vehicle operation was recorded via a manufacturer-independent fleet management system interface and combined with satellite-based positioning data for route reconstruction. After data preprocessing and quality filtering, a total of 3353 valid transport tours were analyzed. Fuel consumption values during HVO100 operation were corrected for density-related measurement bias. The effect of fuel type was evaluated using a linear mixed-effects model. The model accounted for load status, route topography, driving speed, and their interactions. In addition, stratified pairwise comparisons were conducted across operational conditions. The results show that, in the full three-vehicle model, HVO100 was associated with a statistically significant increase in fuel consumption of 0.51 L/100 km under baseline conditions with an empty vehicle, low topographic variability, and medium driving speed, corresponding to approximately 2.3%. In a sensitivity analysis excluding the diesel-only truck, the estimated difference decreased to 0.34 L/100 km and was no longer statistically significant. Load status and topography were identified as the dominant drivers of fuel consumption with substantially larger effects than fuel choice. Overall, the findings indicate that the effect of HVO100 on fuel consumption is small relative to operational variability. Under many real-world operating conditions, operational factors outweighed the differences attributable to fuel type. These findings indicate that switching to HVO100 did not result in a substantial volumetric fuel-consumption penalty in the investigated agricultural logistics system. Full article

Liquefied natural gas (LNG) is increasingly used in maritime propulsion systems to reduce atmospheric emissions. However, methane slip from dual-fuel engines remains a critical limitation due to the high global warming potential of methane. This study presents a comprehensive experimental assessment of greenhouse gas (GHG) emissions from a new-generation low-pressure four-stroke dual-fuel (LPDF 4-S) engine installed on a cruise vessel and operating on both LNG and marine gas oil (MGO). Measurements were carried out during full-scale sea trials under real navigation conditions. Results show that methane slip remains strongly dependent on engine load, with low and stable values at medium-to-high loads (1.95 g·kWh⁻¹ average over the 60–90% range) and a value of 5.6 g·kWh⁻¹ at 26% engine load. Compared with the previous engine generation (46DF), the 46TS-DF engine exhibits an approximate 18% reduction in methane slip above 60% load. On a well-to-wake basis, this results in an overall carbon dioxide CO₂-equivalent emission reduction of about 6%, of which 42% is attributable to methane slip reduction and the remainder to improved energy efficiency. In contrast, switching from MGO to LNG operation leads to a 21% decrease in CO₂-equivalent emissions. Black carbon (BC) emissions were measured and as expected despite the limited number of available studies, they were found to be significantly lower in LNG mode, with reductions exceeding 90% compared with MGO operation. Finally, an Engine Load Monitoring (ELM) analysis based on one year of operational data highlights the strong influence of vessel operating profiles on methane slip. The application of both International Maritime Organization (IMO) and FuelEU Maritime methodologies yields consistent methane slip coefficients (1.34% and 1.36%, respectively), significantly lower than current default values, noting that these estimates do not include crankcase emissions. These results demonstrate the importance of integrating real operational conditions into emission assessment frameworks for LNG-fuelled vessels. Full article

The decarbonization of essential water supply infrastructure is a critical challenge for water-stressed and geographically constrained regions, particularly islands where both water and electricity systems are highly dependent on external or fossil-based resources. In Northern Cyprus, approximately 70% of domestic water demand is met through imported water via pipeline, while electricity generation relies predominantly on fuel oil, resulting in high greenhouse gas emissions and environmental burden. This study evaluates an integrated renewable energy-based supply system using a medium-scale concentrating solar power (CSP) plant with parabolic trough collectors coupled to thermal desalination. The proposed configuration is assessed as an alternative energy-driven infrastructure option for reducing dependence on imported water and fossil-based electricity. System performance was evaluated by estimating electricity and freshwater production under local climatic conditions, demonstrating that the proposed configuration can meet both the associated electrical energy requirements and domestic water demand in the selected region. A cradle-to-gate life cycle assessment (LCA) was conducted to quantify the environmental impacts of the integrated system and support sustainability-oriented decision-making. The LCA results identify residual fossil-based electricity, phosphoric acid consumption, and brine discharge as the main environmental hotspots. Overall, the findings show that CSP-driven desalination can provide a viable and more sustainable option for integrated energy and water supply in water-scarce coastal regions with high solar potential, highlighting its relevance for renewable energy integration, water-energy nexus planning, and resource-efficient infrastructure development. Full article

In oil and gas field development, accurate prediction of the near-wellbore stress distribution is important for ensuring wellbore integrity, particularly in tight shale reservoirs where the medium can be approximated as nearly homogeneous. The large stress gradient and multi-physics coupling of the near-wellbore stress field are key factors limiting high-precision prediction. Physics-informed neural networks (PINNs) allow integration of governing physical laws into network training processes. However, conventional PINNs cannot accurately capture local stress concentration features and lack the ability to generalize across different parameter settings. This study uses the near-wellbore stress concentration problem as an example to improve the prediction accuracy of PINNs through the incorporation of additional physical constraints and modifications to the network architecture. Furthermore, the method is extended to a physics-informed Deep Operator Network (PI-DeepONet) framework with enhanced generalization capability. The results show that, after introducing the proposed constraints, the stress field exhibits strict biaxial symmetry. The angle-adaptive residual module decreases the near-wellbore stress error from about 40–45% to less than 5%. Based on this method, the near-wellbore stress field under different in situ stress combinations can be predicted instantaneously without retraining. Full article

The industrial sector accounts for 34% of global energy consumption, of which heat accounts for 74%, predominantly derived from fossil fuels. Solar Heat for Industrial Processes (SHIP) offers a viable decarbonisation route for low-to-medium temperature applications (80–250 °C)—a range that includes processes such as tequila production. Yet integrated techno-exergo-economic assessments for small-scale, modular systems in agro-industrial contexts remain scarce. This study presents a technical, thermodynamic, and economic evaluation of a 2.5 MW_th parabolic trough collector system with thermocline thermal energy storage, integrated into a tequila production facility in Jalisco, México. A parametric analysis across seven solar multiple configurations identifies $SM=1.258$ as the economic optimum, yielding an annual solar fraction of 35%, a CO₂ reduction of 33.5%, a levelised cost of heat of 75.19 USD/MWh_th (16.3% below the fuel-oil baseline), and a payback period of 13.39 years under full accelerated depreciation. The system’s exergy efficiency (23–28%) is nearly four times that of the stand-alone boiler (6.31%); the analysis further quantifies diminishing returns beyond $SM\approx 1.4$ and demonstrates that México’s accelerated depreciation provision substantially broadens the economically feasible design space. These findings provide a replicable techno-exergo-economic framework for SHIP integration in gas-constrained, high-irradiation industrial regions, supporting decarbonisation efforts in emerging economies. Full article

Offshore geothermal energy and the reuse of decommissioned oil and gas platforms are emerging as linked pathways for reducing the carbon intensity of marine energy supply while extending the value of mature offshore assets. This review examines offshore geothermal development from a full-chain perspective that connects resource assessment, platform and wellbore reuse, heat extraction, medium- and low-temperature conversion, multi-energy coupling, techno-economic evaluation and environmental risk management. The paper first clarifies the resource logic of offshore geothermal systems, especially sedimentary-basin resources that spatially overlap with mature petroleum provinces. It then analyzes two principal engineering routes: the reuse of existing offshore platforms as energy hubs and the reutilization of abandoned wells as open-loop or closed-loop heat-extraction systems. The review finds that platform and wellbore reuse can reduce drilling demand, shorten offshore construction cycles and lower life-cycle environmental burdens, but engineering feasibility remains constrained by wellbore integrity, thermal losses, corrosion and scaling, platform life extension, regulatory liability and the limited availability of field-scale demonstration data. Coupling geothermal energy with offshore wind power, hydrogen production, OTEC and desalination can improve system stability and equipment utilization; however, standardized assessment boundaries and comparable cost models are still insufficient. Future research should focus on resource-engineering-economic integrated assessment, standardized reuse packages, long-term offshore reliability databases, corrosion-resistant material systems, auditable TEA/LCA models and risk-based regulatory frameworks. This review provides a technical basis for offshore geothermal pilot projects and for the low-carbon transformation of offshore oil and gas infrastructure. Full article

The Ediacaran Dengying Formation 2nd Member (hereafter 2nd Member) in the Sichuan Basin is influenced by major tectonic events including the Caledonian, Indosinian, and Himalayan orogenies and this strata has experienced a complex hydrocarbon accumulation history, resulting in inconsistent gas–water contacts. To elucidate this complex history, this study investigates the diagenetic mineral filling sequence within the Dengying 2nd Member in the Penglai area. We integrated data from analytical techniques such as cathodoluminescence (CL), in situ trace element analysis, U–Pb geochronology, and fluid-inclusion microthermometry. Based on these analyses, this study established the paragenetic sequence, incorporating both diagenesis and hydrocarbon accumulation, for the Dengying 2nd Member. This sequence comprises eight distinct phases of mineral precipitation and hydrocarbon emplacement: fibrous dolomite, granular dolomite, fine crystalline dolomite, first-phase bitumen, medium crystalline dolomite, saddle dolomite, second-phase bitumen, and quartz. From this sequence, we propose a four-stage hydrocarbon accumulation model for the Dengying Formation: (1) primary migration and accumulation during the Indosinian period; (2) oil cracking to gas during the Yanshanian period; and (3) and (4) two distinct stages of gas pool adjustment during the Himalayan period. Corresponding to these stages, this study developed distinct accumulation models and simulated migration and accumulation processes during key stages. The results indicate that the distribution of paleo-oil pools exerts significant control over the location of present-day gas accumulations. Initial oil charge was controlled by the distribution of carrier beds and hydrocarbon charging pathways, with water zones observed more frequently in the lower intervals of the Dengying 2nd Member. Subsequently, gas generated from oil-cracking filled these carrier beds, with areas of gas enrichment correlating with zones of high paleo-oil saturation. Finally, during the later adjustment stages, fault activity induced gas remigration and leakage, significantly impacting the final trapping configuration and preservation of gas accumulations. Full article

Heavy and highly viscous oils account for a significant proportion of the world’s hydrocarbon reserves. The development of these reserves in harsh climates is associated with technological risks due to paraffin deposits and equipment corrosion. Ensuring reliable transportation requires operational monitoring of the physical and chemical properties of fluids directly at the wellhead. Traditional laboratory methods such as SARA fractionation and gas chromatography (GC) are time-consuming and can yield to distortions in the sample composition during transportation. Field optical methods, such as an infrared (IR) spectroscopy are complicated by the optical heterogeneity of crude oils due to emulsified water, supramolecular associations of resins, asphaltenes, and paraffins. In this paper, ultrasonic (US) sample preparation for high-viscosity oils is justified as a method for increasing the reliability and information content of field IR spectroscopic analysis by unmasking the diagnostic extrema of absorption bands that are initially distorted by emulsified water, baseline scattering, and radiation scattering from large resin–asphaltene–paraffin aggregates. The technique is based on cavitation-induced destruction of emulsion shells and disaggregation of the structural framework without volume thermal heating. Experimental data obtained from watered high-viscosity oil has shown that 9 min of the US exposure reduces the light scattering index $I_{\mathrm{t}\mathrm{r}\mathrm{s}}$ by 92.83%, bringing the system into a less heterogeneous state. Statistical correlation analysis confirmed that emulsions and aggregates are the main scattering centers, and their destruction correlates directly with the transparency of the medium. Stability of spectral indices $I_{{\mathrm{C}\mathrm{H}}_3/{\mathrm{C}\mathrm{H}}_2}$, $I_{\mathrm{f}\mathrm{o}\mathrm{c}}$ and $I_{\mathrm{C}=\mathrm{O}}$ indicates the absence of chemical degradation or oxidation at the US exposure intensity of 0.12 W/mL, confirming the physical nature of the effect. The proposed method makes it possible to implement automated monitoring of the properties of high-viscosity oil directly at the wellhead, minimizing logistic costs and risks of the sample degradation. The practical significance of the proposed method is to improve the reliability and information content of wellhead monitoring by reducing optical heterogeneity and making diagnostic significant IR absorption extremes more distinguishable for further interpretation. Full article

This Communication reports limited engineering screening data on polymer liner candidates for flexible composite pipes used in oil and gas service. Three exposure conditions were considered: hydrothermal aging in superheated water, thermal-oxidative aging in dry air, and hydrocarbon-medium exposure. Superheated-water immersion for up to 1000 h, dry-air aging for 168 h, and 7-day hydrocarbon exposure were used to describe changes in tensile properties, Shore hardness, mass, and thickness. Complete replicate records were available only for the thermal-oxidative aging dataset; therefore, most hydrothermal and hydrocarbon-medium results are reported as descriptive summary data. In the recorded data, EPDM formulation CL-2-1 retained approximately 89% of its tensile strength after 1000 h in superheated water. Sample L showed a smaller mean tensile-strength decrease than Sample Z after 168 h at 150 °C in dry air. In the hydrocarbon-medium summary data, XL95A/05B-S1 showed lower mass increase and smaller tensile-strength and yield-stress decreases than PERT XRT70H across the tested temperature range. The Communication provides case-specific screening evidence and identifies the need for replicated testing, statistical analysis, longer aging series, and structural characterization before general material-selection or durability conclusions are made. Full article