The production of high-quality biodiesel from vegetable oils requires an integrated approach that considers feedstock quality, transesterification, and final product purification. This study investigates a comprehensive technological sequence for soybean biodiesel production combining enzymatic degumming, treatment with biosurfactant-containing microbial culture fluid, cavitation-assisted transesterification, and adsorptive dry purification. Enzymatic pretreatment using the multienzyme preparation Purifine® 3G in combination with culture fluid obtained from Pseudomonas fluorescens cultivation was associated with reductions in residual phosphorus and sulfur contents and acid value, potentially due to improved enzyme-substrate interactions, although increasing the culture-fluid dosage prolonged phase separation. Cavitation-assisted transesterification produced biodiesel with a higher fatty acid methyl ester (FAME) mass fraction than conventional stirred-reactor processing under the investigated operating conditions, while spectroscopic and chromatographic analyses confirmed the formation of products with similar FAME profiles. A comparative evaluation of three purification schemes demonstrated that direct adsorptive dry purification using natural clinoptilolite provided the highest FAME mass fraction without requiring an additional water-washing step. Industrial-scale testing confirmed the applicability of clinoptilolite-based adsorptive conditioning for reducing residual water content while maintaining a high ester content. Overall, the findings support the technical feasibility of integrating enzymatic feedstock pretreatment, transesterification, and adsorptive conditioning into soybean biodiesel production and identify key aspects for further process optimization and industrial validation.
To evaluate how field-applied imbibition agents affect oil recovery and pore-scale oil mobilization in Chang 8 tight sandstone, natural cores from Longdong, Ordos Basin, were tested using CNI-A, CQH-1, and EOS-3. Surface tension, oil–water interfacial tension, and contact angle were measured at different concentrations. Solutions with a mass fraction of 0.3% were selected for 144 h macroscopic imbibition tests and 96 h nuclear magnetic resonance measurements at 18 MPa. All three agents reduced surface and oil–water interfacial tension and altered core wettability. At a mass fraction of 0.3%, EOS-3 achieved the lowest oil–water interfacial tension (0.03 mN/m), whereas CQH-1 produced the highest average recovery after 144 h (32.9%), compared with 21.9% for CNI-A and 20.6% for EOS-3. Nuclear magnetic resonance relaxation-time distributions indicated oil mobilization across different pore populations and supported the stronger sustained performance of CQH-1. This contrast shows that interfacial tension alone cannot determine imbibition performance. In the field trial, Well X treated with CQH-1 showed a 28.4% increase in average daily oil production during the first month and a 23.1% increase in cumulative oil production over 90 days. Imbibition performance reflects the combined effects of wettability alteration, capillary driving force, interfacial resistance, and pore-throat structure. This study provides an experimental basis for selecting imbibition agents for Chang 8 tight sandstone reservoirs in Longdong.
Well-trajectory optimization is frequently framed as maximizing reservoir contact, although additional contact does not necessarily enlarge the dynamically connected drainage volume. Here, vertical, J-shaped and horizontal trajectories were evaluated at three locations in the Upper Safa reservoir (Middle Jurassic Khatatba Formation), Western Desert, Egypt, using a controlled Petrel–ECLIPSE workflow that combines simulated cumulative reservoir response with relative drilling complexity under a consistent reservoir model realization. For every location, the reservoir realization, target interval, and operating constraints were held constant, and only the well path and completed grid cells were varied. The resulting nine cases were compared using modeled contact length, early productivity index, cumulative oil and gas recovery, and an authorization for expenditure (AFE)-based relative drilling cost index, used as a decision support indicator rather than a full economic evaluation. Within these single realization cases, the trajectory ranking was location-specific: vertical at SE-1X (1.92 MMSTB oil, 8.6 BSCF gas), J-shaped at SW-1X (1.78 MMSTB, 8.2 BSCF) and horizontal at SE-5 (1.55 MMSTB, 8.7 BSCF). The SE-1X and SW-1X selections were supported by implemented well geometries and production test observations, whereas the SE-5 horizontal case remains a simulation-based outcome because it was not field-implemented. The horizontal cases returned the highest early productivity index at every location but the highest cumulative recovery only at SE-5, indicating that geometric exposure alone was not sufficient to predict cumulative recovery. Directional surveys and discrete production tests for the two implemented wells were consistent with the selected simulation cases (oil-rate MAPE 7.0–7.9%; gas-rate MAPE 2.3–4.9%). Overall, cumulative response, interpreted together with reservoir quality and connectivity diagnostics, provided a more informative basis for trajectory optimization than geometric contact length alone.
The paper investigates the effect of ultrasonic cavitation, in combination with catalysts, on the fractional composition of high-viscosity oil. Ultrasonic treatment was carried out at a frequency of 22 kHz and a power of 50 W for 10 min in the presence of HY-zeolite, NiFe/Y-zeolite and NiFe/microsphere (1 wt%) catalysts. Results showed that ultrasonic treatment without a catalyst leads to a reduction in the yield of the target distillate fractions. The HY-zeolite demonstrates the greatest efficiency, increasing the yield of the light fraction with a boiling point of up to 200 °C by 7.9% compared with the initial oil. The NiFe/zeolite and NiFe/microsphere catalysts contributed to the formation of naphthenic and aromatic structures in the light and middle fractions of high-viscosity oil; however, the yields of light fractions with a boiling point of up to 200 °C and at 200–300°C decreased.
To address limited permeability enhancement caused by insufficient free faces during static fracturing in low-permeability coal seams, this study investigated the No. 2 coal seam of the 32203 working face in Hanzui Coal Mine. A coupled stress–damage–seepage fluid–solid model was developed, and COMSOL Multiphysics 6.0 was used to compare stress, plastic zone, and gas pressure evolution under single-borehole and grid-pattern multi-borehole fracturing. Simulations showed that single-borehole fracturing was constrained by the free face, with limited lateral plastic-zone expansion (0.45 m) and non-uniform distribution due to in situ stress and coal anisotropy. In grid-pattern fracturing, drainage boreholes provided multiple free faces; superimposed expansion stresses connected plastic failure zones around fracturing boreholes, enlarging pressure relief. Field tests with six fracturing and six observation boreholes, using stable flow after secondary sealing as baseline and excluding sealing improvement, showed mixed drainage flow increased by 2.5–3.1 times and pure-gas flow by 2.1–2.5 times; pure flow at 0.6 m from a fracturing borehole rose from 0.0046 to 0.018 m3/min. Permeability enhancement was significant at spacing ≤1.6 m, consistent with simulations. Grid-pattern static fracturing expanded the fracture network via stress–damage–seepage coupling, providing a theoretical basis and parameter reference for efficient permeability enhancement in low-permeability coal seams.
