Search

Following hydraulic fracturing operations within shale reservoirs, there frequently exists a considerable volume of residual oil that remains encapsulated within the matrix, thereby impeding the singular shale well's productivity from attaining projected yields. In pursuit of augmenting the recovery efficiency of shale oil, the industry has widely adopted a post-fracture shut-in strategy within shale oil wells. This methodology is predicated on the aspiration to escalate both the production output and the recovery factor of the oil well by leveraging the imbibition and displacement mechanisms of the fracturing fluid throughout the shut-in interval. There are many kinds of surfactants, and how to select surfactants suitable for shale reservoirs from these many surfactants has become a key issue in improving shale reservoir recovery. In this study, a new surfactant screening method for improving imbibition recovery in shale reservoirs is proposed. An interfacial tension test, contact angle test, and anti-adsorption test are carried out for the collected surfactant products, and the interfacial tension, contact angle, and anti-adsorption are gradually used as indicators. The type of surfactant is initially screened. On this basis, the static imbibition experiment of shale is made to determine the type and concentration of surfactants suitable for shale oil development. The results show that the surfactants screened by this method have the characteristics of decreasing oil–water interfacial tension, varying rock wettability, and strong anti-adsorption, which can effectively improve imbibition efficiency. The study results herein can provide technical support for optimizing shale oil surfactants and provide a new idea for improving oil exploitation in low-permeability reservoirs. [ABSTRACT FROM AUTHOR]

Water desalination is crucial for addressing global water scarcity affecting over 2 billion people. By 2050, water demand could rise by 20-30% due to population growth and urbanization. Currently, over 40% of the global population lacks access to clean water due to overexploitation of conventional sources like rivers and groundwater. This report focuses on experimental analysis of brackish water desalination, primarily using reverse osmosis (RO). Desalination plays a vital role in converting seawater or brackish water into drinkable water, especially in coastal areas. The study explores various desalination methods such as ion exchange, membrane distillation, and vapor compression distillation. Technological advancements, particularly in RO distillation process has enhanced efficiency and sustainability. In this report, pre-treatment processes, including filtration, chemical dosing, antiscalant injection, water softening, are also employed to remove contaminants before desalination. The performance of RO is evaluated based on factors like pressure drop, feed flow rate, and recovery ratio, analyzing water flux, salt rejection rate, energy consumption, and system efficiency. The results provide insights into optimizing brackish water desalination and the discussions are carried out for improvement of the ways such as post treatment, membrane cleaning and advancement in membrane materials for sustainable freshwater production.

Water desalination is crucial for addressing global water scarcity affecting over 2 billion people. By 2050, water demand could rise by 20-30% due to population growth and urbanization. Currently, over 40% of the global population lacks access to clean water due to overexploitation of conventional sources like rivers and groundwater. This report focuses on experimental analysis of brackish water desalination, primarily using reverse osmosis (RO). Desalination plays a vital role in converting seawater or brackish water into drinkable water, especially in coastal areas. The study explores various desalination methods such as ion exchange, membrane distillation, and vapor compression distillation. Technological advancements, particularly in RO distillation process has enhanced efficiency and sustainability. In this report, pre-treatment processes, including filtration, chemical dosing, antiscalant injection, water softening, are also employed to remove contaminants before desalination. The performance of RO is evaluated based on factors like pressure drop, feed flow rate, and recovery ratio, analyzing water flux, salt rejection rate, energy consumption, and system efficiency. The results provide insights into optimizing brackish water desalination and the discussions are carried out for improvement of the ways such as post treatment, membrane cleaning and advancement in membrane materials for sustainable freshwater production. [ABSTRACT FROM AUTHOR]

The characteristics of geological reservoirs are an important means to evaluate the feasibility of water injection development. The differences in reservoir characteristics in different regions make it difficult to scale up the promotion of water injection development parameters. A more effective way is to establish efficient water injection development methods and strategies suitable for the region. Therefore, based on the geological characteristics of the Wucangbao Chang 6 and Chang 9 oil reservoirs, the feasibility of water injection development in Wucangbao reservoir is analyzed from several aspects such as interstitial material content, reservoir hydrophilicity, and stress sensitivity. The water injection parameters of Wucangbao Chang 6 and Chang 9 single wells are calculated using methods such as apparent flow rate method, permeability and single well productivity regression method, and stratigraphic series curve regression method, respectively. The water injection parameters are obtained based on the single well production. The results show that the Wucangbao Chang 6 and Chang 9 reservoirs have good water injection feasibility and prospects in terms of sandstone cement, reservoir fluid properties, wettability, and water flooding efficiency; And the production of single well Chang 6 is 1.5-4.0 t/d, while the production of single well Chang 9 is 2.0-4.5 t/d; According to the injection production balance, the initial single well injection volume of the Wucangbao Chang 6 layer is 10 m3, and the initial single well injection volume of the Chang 9 layer is 20 m3, in order to maximize the recovery rate of the reservoir during the dry or low water cut period. [ABSTRACT FROM AUTHOR]

Copyright of Oilfield Chemistry is the property of Sichuan University, Oilfield Chemistry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the effects of different designs of pressure vessels on hydrodynamic parameters and the performance of seawater RO systems are investigated using computer simulations. Simulation results showed that designs using pressure vessels with four membranes in two-pass RO systems have a lower energy consumption, 5.29 and 0.33 kWh/m3 for the first and second passes, respectively, than those with two or three membranes. Also, designs No. 4 and No. 10 were the most efficient, 41 and 56% for the first and second passes, respectively, compared to other ones. The first and second passes required a lower permeate and feed pressure when using designs No. 3, No. 6, No. 9, and No. 12 where pressure vessels with two membranes were used. In addition, hybrid designs of two-pass RO systems were found to have the best efficiency and the lowest energy consumption among various other designs. Findings showed that in two-pass RO systems, the first pass consumes more energy than the second pass. Thus, the efficiency of the second pass in all designs of two-pass RO systems is more than the first pass. The results presented in this paper can be used to optimize the design of two-pass RO systems to ensure the optimum operation of such systems. [ABSTRACT FROM AUTHOR]

The strategy of integrating water injection and chemical additives in combining secondary and tertiary oil recovery techniques has been widely investigated in enhancing oil recovery efficiency. Nevertheless, there is a lack of sufficient evidence on the effectiveness of a mixture of cationic and nonionic surfactants combined with water injection techniques in enhancing recovery in the application of carbonate reservoirs. Therefore, it is particularly critical to explore the impact of this combination strategy in enhancing recovery in fractured carbonate reservoirs. The recovery enhancement effect can be assessed by conducting phase behavior experiments and determining interfacial tension and contact angle. Further, the effectiveness of specific surfactant ration solutions in enhancing recovery can be verified by performing drive-off experiments. The results show that low mineralization water and surfactants have a significant synergistic effect in enhancing the recovery efficiency of carbonate reservoirs, with the optimal ratio of cationic to non-ionic surfactants being 2.5:1. The optimized surfactant ratio is able to increase the recovery of carbonate reservoirs by 20% compared to the original recovery rate. [ABSTRACT FROM AUTHOR]

The strategy of integrating water injection and chemical additives in combining secondary and tertiary oil recovery techniques has been widely investigated in enhancing oil recovery efficiency. Nevertheless, there is a lack of sufficient evidence on the effectiveness of a mixture of cationic and nonionic surfactants combined with water injection techniques in enhancing recovery in the application of carbonate reservoirs. Therefore, it is particularly critical to explore the impact of this combination strategy in enhancing recovery in fractured carbonate reservoirs. The recovery enhancement effect can be assessed by conducting phase behavior experiments and determining interfacial tension and contact angle. Further, the effectiveness of specific surfactant ration solutions in enhancing recovery can be verified by performing drive-off experiments. The results show that low mineralization water and surfactants have a significant synergistic effect in enhancing the recovery efficiency of carbonate reservoirs, with the optimal ratio of cationic to non-ionic surfactants being 2.5:1. The optimized surfactant ratio is able to increase the recovery of carbonate reservoirs by 20% compared to the original recovery rate.

Runoff‐generated debris flows are a potentially destructive and deadly response to wildfire until sufficient vegetation and soil‐hydraulic recovery have reduced susceptibility to the hazard. Elevated debris‐flow susceptibility may persist for several years, but the controls on the timespan of the susceptible period are poorly understood. To evaluate the connection between vegetation recovery and debris‐flow occurrence, we calculated recovery for 25 fires in the western United States using satellite‐derived leaf area index (LAI) and compared recovery estimates to the timing of 536 debris flows from the same fires. We found that the majority (>98%) of flows occurred when LAI was less than 2/3 of typical prefire values. Our results show that total vegetation recovery is not necessary to inhibit runoff‐generated flows in a wide variety of regions in the western United States. Satellite‐derived vegetation data show promise for estimating the timespan of debris‐flow susceptibility. Plain Language Summary: Debris flows caused by excessive surface‐water runoff during intense rainfall can be a deadly and destructive hazard in mountainous areas after wildfire. In some cases, debris flows have only occurred in the burned area in the weeks to months after the fire, while, in other cases, debris flows occurred over several years. Though the recovery of vegetation is important for stabilizing sediment and reducing debris‐flow likelihood, uncertainty remains about how much recovery is needed to inhibit debris flows and about how much time is needed to reach this level of recovery. Knowing for how long debris flows are likely to be a hazard is important for managing risks to residents and infrastructure. To investigate this issue, we assembled a data set of 536 debris flows from the western United States and used satellite‐derived vegetation data to calculate the recovery condition of the burned area when each debris flow occurred. We found that the vast majority of the debris flows initiated when the burned area had not yet reached two‐thirds of its prefire vegetation condition. Burned areas that were slower to recover tended to experience debris flows over more protracted timescales. Key Points: Majority (>98%) of western United States postfire debris flows occurred when leaf area index was less than 2/3 of typical prefire valuesTotal recovery of vegetation not necessary to inhibit debris flowsRemotely sensed postfire vegetation state useful to evaluate elevated debris‐flow susceptibility with time [ABSTRACT FROM AUTHOR]

Aiming at the problems of low recovery ratio and high water content of high-salt heavy oil reservoir in East Sha DS Formation. Area 2 of Shengtuo oilfield. the enhanced oil recovery effect of six polymers was evaluated through laboratory experiments, and the polymer suitable for enhancing. the recovery ratio of high-salt heavy oil reservoir was selected. The specific injection scheme of polymer flooding to enhance the recovery ratio of high-salt heavy oil reservoir was optimized by ECLIPSE software. The research shows that the new 2# polymer has better oil displacement effect than other polymers, and it is recommended to use two slugs for injection. The specific injection scheme is 0.1 PV and 2 500 mg/L. 0.3 PV and 2 000 mg/L.. the injection rate is 0. 07 PV/a mother liquor is prepared with clean water, and sewage is diluted and injected. The field test results show that there are 50 effective wells using polymer flooding, with an effective rate of 98. 1%. cumulative oil increase of 393 000 tons and staged enhanced oil recovery of 9. 03%. The research results have important guiding significance for the industrial popularization of polymer flooding in Shengli Oilfield and the enhanced oil recovery of high-salt heavy oil reservoirs by combination flooding. [ABSTRACT FROM AUTHOR]

Abstract Runoff‐generated debris flows are a potentially destructive and deadly response to wildfire until sufficient vegetation and soil‐hydraulic recovery have reduced susceptibility to the hazard. Elevated debris‐flow susceptibility may persist for several years, but the controls on the timespan of the susceptible period are poorly understood. To evaluate the connection between vegetation recovery and debris‐flow occurrence, we calculated recovery for 25 fires in the western United States using satellite‐derived leaf area index (LAI) and compared recovery estimates to the timing of 536 debris flows from the same fires. We found that the majority (>98%) of flows occurred when LAI was less than 2/3 of typical prefire values. Our results show that total vegetation recovery is not necessary to inhibit runoff‐generated flows in a wide variety of regions in the western United States. Satellite‐derived vegetation data show promise for estimating the timespan of debris‐flow susceptibility.

Several numerical simulations of RF heating have been carried out previously on the estimation of heavy oil recovery capabilities. Experimental efforts, however, are needed to comprehensively evaluate the performance of RF heating technology. In this study, an RF heating experimental system with the maximum output power of 20 kW is designed. In this system four special custom-made experimental pipes provide the space where the interaction between EM waves and oil sands occurs. Temperature data are recorded continuously by fiber optic temperature sensors. Initially, the temperature profiles of oil sands and quartz sands at 10 kW are obtained. Afterward, the step changes in temperature of pipes bottoms are captured to investigate the drop process of heavy oil. The influences of different powers and distances from the antenna on temperature and recovery ratio are analyzed. Finally, according the measured data, the calculation for the energy to oil ratios under various combinations of time and power is done to evaluate the energy consumption of RF heating technology. Experimental results indicate that the power increase contributes to improve the oil sands temperature, shorten the time required for heavy oil to flow and cause high average recovery ratio. The capability of oil sand to absorb EM waves is stronger than that of quartz sands. Additionally, the effects of distance from antenna on average recovery ratio are in good agreement with the change rules of temperature. There exists an optimal combination of heating power and time that makes the lowest value of energy to oil ratio. [ABSTRACT FROM AUTHOR]

Dimension-stone quarrying optimization is significantly important to increase the recovery ratio of dimension stone and to reduce the cutting cost. Due to fracture-existed rock mass, in the mining operation block size and mining direction influences to the recovery ratio and the cutting cost. Therefore, the paper suggests the quarrying optimization for dimension stone to obtain the highest recovery ratio and the lowest cutting cost, based on optimizing block size and mining direction to get a cutting grid of dimension stone. Through developing an integrated modelling between joint set modelling and cutting grid modelling, intact blocks and fractured blocks were generated. From this, block statistics were conducted to get the maximum recovery ratio of dimension stone and the minimum cutting rate between the cutting area and the recovered block volume, which helps to choose an optimizing block size and mining direction. The research was carried out at Tan Long dimension stone quarry where a block size (0.9m x 0.6m x 1.35m) and a mining direction paralleling to joint set 1 will ensure the highest recovery ratio of 13.87% and the lowest cutting rate of 25 m²/m³. [ABSTRACT FROM AUTHOR]

The recovery ratio of longwall top coal caving (LTCC) technology is an important measure of its effectiveness. However, the recovery ratio of single-opening sequential caving technology in thick and extra-thick coal seams needs improvement. To address this, an independent cluster-group caving technology is proposed in this study. Four numerical simulation experiments were conducted to compare the recovery ratio and drawing balance of four-opening independent cluster-group caving technology and single-opening sequential caving technology. Results show that the recovery ratio in four-opening independent cluster-group caving technology is approximately 6% higher than in single-opening sequential caving technology when the thickness of the broken gangue layer and the coal seam are the same. Additionally, a judgment formula for the broken immediate roof thickness is provided when the top coal recovery ratio is seriously affected. The independent cluster-group caving technology demonstrates stronger stability and better adaptability under different conditions, as its caving sequence can prevent larger thickness changes and gangue disturbances during the drawing process. Overall, this study highlights the potential of independent cluster-group caving technology to improve the recovery ratio of LTCC technology in thick and extra-thick coal seams. [ABSTRACT FROM AUTHOR]

In order to provide a comprehensive reference for the study of carbon dioxide displacement of coalbed methane, this paper explores the influence of different influencing factors on coal adsorption capacity, analyzes the gas migration and adsorption principle in coal bed, as well as the difference and relationship between different adsorption models, and introduces the pilot test and application of CO2-enhanced coalbed methane recovery in different countries. Using VOSviewer software and CNKI metrological visualization analysis function, this paper analyzes the annual publication trend and keyword time trend of CO2-ECBM related literature in CNKI and Web of Science databases, and discusses the problems existing in CO2-ECBM. The results show that coal rank and pore structure, temperature and pressure, moisture content and other factors can affect coal adsorption capacity in different forms. Gas migration in coal seam is a complex system composed of adsorption/desorption-diffusion-seepage. The best adsorption model should be considered in studying coal adsorption gas. Based on VOSviewer analysis, CO2-ECBM research is a hot topic in China. The research direction has gradually shifted from macroscopic geological storage evaluation to reveal the mechanism of coal storage and displacement gas from microscopic or molecular levels such as pore structure and composition of coal, and multi-field coupling simulation of CO2-ECBM.

Background: There is a scarcity of literature that examines clinical outcomes through patient-reported outcomes (PROs), minimum clinically important difference (MCID), and recovery ratios (RR) for workers' compensation (WC) recipients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) versus anterior lumbar interbody fusion (ALIF). Methods: WC claimants undergoing MIS-TLIF versus ALIF were propensity score matched to account for demographic differences. Demographics, perioperative characteristics, and PROs were collected. PROs of Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), 12-Item Short Form Physical Composite Score (SF-12 PCS), Visual Analog Scale (VAS) back, VAS leg, and Oswestry Disability Index (ODI) were collected at preoperative and postoperative time points. MCID achievement was determined through comparison to values in literature. RR was calculated as the difference between postoperative and preoperative PROs over potential improvement. Comparison between surgical techniques was through non-parametric inferential statistics. Results: Eighty-four WC claimants, with 50 patients undergoing MIS-TLIF, were identified after propensity score matching. ALIF patients had higher estimated blood loss. MIS-TLIF patients had higher postoperative day (POD) 0 VAS pain and POD 0 + 1 narcotic consumption. Patients undergoing either MIS-TLIF or ALIF reported significant improvement in pain and disability. ALIF patients reported significant improvement in physical function. ALIF patients reported superior 1-year PROMIS-PF, 6-week SF-12 PCS, 6-month VAS back, and 12-week VAS leg. No significant differences in MCID achievement rates were noted between cohorts. ALIF patients had higher RR in 6-week and 1-year PROMIS-PF and 6-week SF-12 PCS. Conclusion: Workers' compensation claimants undergoing either MIS-TLIF or ALIF reported significant improvement in pain and disability. ALIF patients reported superior postoperative physical function and pain. ALIF patients had higher recovery ratios in physical function. Workers' compensation claimants undergoing ALIF may experience greater physical function recovery and superior clinical outcomes in physical function and pain. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop and characterize polyurethane-based shape memory polymer filament yarns of a suitable diameter and thermo-mechanical performance for use in tailored multi-sectorial applications. Different polymer compositions – pure shape memory polyurethane and shape memory polyurethane composites with 0.3 and 0.5 wt.% of multi-walled carbon nanotubes or carbon black as additives – were studied. Filaments were obtained using a melt spinning process that allowed the production of the permanent and temporary shape of the shape memory polyurethane filament. Two drawing speeds (20 and 32 m/min) were studied. Characterization techniques such as the tensile test, differential scanning calorimetry, and dynamic mechanical analysis were used to investigate the shape-memory effect of the filaments. Pure and additive shape memory polyurethane filament yarns of a controlled diameter were produced. The results indicated that the pure shape memory polyurethane on the temporary shape had the highest tensile strength (234 MPa). Filaments with carbon black revealed a significant strain (335%) in the permanent shape with respect to the other filaments. The melt spinning process influenced the soft segment glass transition temperature (Tgs) significantly, with a decrease in the temporary shape (first heating) as compared to the permanent shape (second and third heating). However, only the 0.5% multi-walled carbon nanotubes additive clearly influenced the filament, increasing the Tgs by 10°C. The additives also influenced the shape-memory effect, obtaining an increased fixity ratio (up to 97%) with the multi-walled carbon nanotubes additive and an increased recovery ratio (up to 86%) with the carbon black additive. [ABSTRACT FROM AUTHOR]

The topography and location of many remote islands limit the available freshwater resources present for use by the inhabitants. However, the abundance of solar and seawater resources and small population size makes them ideal candidates for solar still application. A prototype solar still was designed and fabricated for use on such applications; however, for its implementation, a statistical model was developed to assess its productive performance at a pilot location, Dongji Islet. Experiments were conducted to collect data and construct a multivariable regression model by means of the jack-knife procedure and best subsets technique. The model was then used to size the solar still for implementation by applying the TMY data of Dongji Islet. The daily total global solar radiation, average ambient temperature, and extent of cloud cover were found to be the most suitable predictor variables for the model based on their correlation to the productivity of the protype solar still and their p-value. The model predicted a maximum daily yield of 5.88 L/day in July and a minimum of 1.97 L/day in December. In relation to the annual predicted yield, the length of the solar still can be increased by 88.6% in order to satisfy the daily minimum requirement of 7.5 L per day per person. [ABSTRACT FROM AUTHOR]

To explore the synergistic mechanism of polymer and surfactant in the binary combination flooding of low-permeability reservoirs, the adaptability experiment of polymer salt-resistant partially hydrolyzed polyacrylamide and nonionic surfactant was carried out in the indoor system. Experiments at different ratios are also performed. The results show that the selected poly/surface binary flooding system increases with the concentration of polymer or surfactant, the viscosity of the poly/surface binary system also increases and, at the same time, has better temperature and salt resistance. The viscosity of the binary system will decrease when the salinity increases. When the surfactant concentration CS = 0.2% and the polymer concentration CP = 0.2%, the viscosity of the system is the highest. The viscosity of the poly/table binary system at different concentrations decreases when the temperature rises: pure polymer (CP = 0.2%), poly/table binary system displacement fluid CP = 0.1% + CS = 0.2% and CP = 0.2% + CS = 0.2%; and the injection pressure first rises and then drops. The final recovery rate is 51.8%, which meets the development of most oil reservoirs.

• Hybridization of mechanical vapor compression desalination with membrane distillation. • Analysis of the hybrid system under different flow arrangements. • Analysis of boosting first effect by the vapor of the last three effects. • Analysis of boosting intermediate effect by the vapor of the penultimate effect. • Assessing the production and specific energy consumption of the novel systems. Retrofitting the multi-effect mechanical vapor compression (MEMVC) process for water desalination through hybridization with membrane distillation (MD) and/or employing vapor boosting mechanism is investigated in this work. The impact of using more than one mechanical compression, their respective locations and flow rates is investigated. Integration of parallel feed scheme of MEMVC with MD owned the maximum MD water production compared to the hybrid forward feed and parallel cross feed arrangements that can reach up to 54 % enhancement. However, the contribution of the MD production to the total production of the hybrid system does not exceed 17 %. Recycling the vapor of the last three effects to boost the first effect indicated a positive impact. The MEMVC with parallel feed can achieve 134 % water production enhancement with 26 % increase in the specific energy consumption over the nominal condition, i.e., when only the steam of the last effect is recycled to the first effect. Recycling the vapor of the penultimate effect to boost the second effect illustrated superior performance compared to that of boosting the first effect. It is found that the MEMVC with forward feed can attain 61 % improvement in water production with 14 % reduction in the specific energy consumption. [Display omitted] [ABSTRACT FROM AUTHOR]

Total dissolved gas (TDG) supersaturation caused by flood discharge water is becoming a serious environmental problem that threatens the survival of fish. The swimming ability of fish may be influenced by TDG supersaturation. To investigate the effects of continuous exposure to TDG supersaturation on fish swimming ability, we measured the critical swimming speed (Ucrit) and burst swimming speed (Uburst) of grass carp continuously exposed to TDG supersaturation. The Ucrit values of grass carp were 6.34–3.68 body length per second (BL/s) at 100%, 105%, 110%, 115%, 120%, 125%, 130% and 135% TDG, while the Uburst values were 10.2–8.96 BL/s at these TDG levels. The swimming ability (Ucrit and Uburst) of grass carp decreased with increasing TDG levels and was significantly decreased at higher TDG levels (>120%). A swimming ability recovery test was used to investigate the effects of recovery on the swimming ability of grass carp continuously exposed to TDG supersaturation. When grass carp experienced exposures of 115%, 120%, 125%, 130% and 135% TDG, the recovery ratios of Ucrit were 76%–82% and 77%–86% after recovering for 1 and 2 h, respectively, in freshwater (100% TDG). The recovery ratios of Uburst of grass carp were 84%–98% and 95%–97% under the same recovery conditions and TDG levels. The results showed that the recovery ratios of both Ucrit and Uburst increased with the extension of the recovery time. The swimming ability of grass carp provided with a 2‐h recovery time recovered almost completely. [ABSTRACT FROM AUTHOR]

The size distribution of the broken top coal blocks is an important factor, affecting the recovery ratio and the efficiency of drawing top coal in longwall top coal caving (LTCC) mining panel. The standard deviation of top coal block size (δt) is one of the main parameters to reflect the size distribution of top coal. To find the effect of δt on the caving mechanism, this study simulates experiments with 9 different δt by using discrete element software PFC. The δt is divided into two stages: uniform distribution stage (UDS) whose δt is less than 0.1 (Schemes 1–5), and nonuniform distribution stage (NDS) whose δt is more than 0.1 (Schemes 6–9). This research mainly investigates the variation of recovery ratio, drawing body shape, boundary of top coal, and contact force between particles in the two stages, respectively. The results showed that with the increasing δt, the recovery ratio of the panel increases first and then decreases in UDS. It is the largest in Scheme 3, which mainly increases the drawing volume at the side of starting drawing end. However, the recovery ratio decreases first and then increases quickly in NDS, and it is the largest in Scheme 9, where the drawing volume at the side of finishing drawing end are relatively higher. In UDS, the major size of top coal is basically medium, while in NDS, the size varies from medium to small, and then to large, with a distinct difference in shape and volume of the drawing body. When the major size of top coal is medium and small, the cross-section width of the initial boundary of top coal at each height is relatively small. Conversely, when the top coal size is large, the initial boundary of top coal has a larger opening range, the rotating angle of lower boundary is relatively small in the normal drawing stage, which is conducive to the development of drawing body and reduces the residual top coal, and the maximum particle velocity and the particles movement angle are both larger. This study lays a foundation for the prediction of recovery ratio, and suggests that the uniform top coal is more manageable and has a larger recovery ratio.

Abstract The pore‐scale imbibition mechanism in fractured water‐wetted reservoirs has been acknowledged as an efficient tool to enhance oil recovery. Most rock in a natural reservoir is mixed‐wetted, but most studies on the pore‐scale imbibition process only focused on the water‐wetted rock. This paper adopts two mixed‐wetted core samples for microspontaneous imbibition experiment, micro‐CT scanning, and nuclear magnetic resonance (NMR) test. The results indicate that the pore radius distribution of the segmented CT images is consistent with that of the NMR test. The microimbibition recovery ratio of core No. 34‐1 and core No. 64 in the spontaneous imbibition experiment are 27.7% and 58.2%, which agrees well with that computed by the micro‐CT scanning image (27.63% and 56.09%). Based on the segmented images, the influences of the Jamin's effect, pore size distribution, and wettability on the microspontaneous imbibition are visualized and quantitatively studied. The Jamin's effect is the important factor that hinders the microimbibition process. The main pore size of imbibition distributes in the range of 1‐25 μm. Furthermore, the pore‐scale spontaneous imbibition process in a single pore with mixed wettability is investigated and analyzed. The relationships among the contact angle, capillary force, recovery ratio, wettability, and the microimbibition recovery are revealed.

To compare outcomes between minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and anterior lumbar interbody fusion (ALIF) at L5/S1. Primary, elective, single, MIS-TLIF, or ALIF with posterior fixation at L5/S1 were identified. Patient-reported outcome measures (PROMs) were collected. Coarsened exact matching was used to control for significant differences. Achievement of minimum clinically important difference [MCID] was determined by comparing ΔPROM scores with threshold values. Demographic/perioperative characteristics were compared between MIS-TLIF and ALIF cohorts using χ2 Student t tests. Differences in mean PROM scores, MCID rates, and postoperative complications were evaluated using an unpaired t test. After coarsened exact matching, 93 patients received MIS-TLIF and 50 received ALIF. Cohorts differed in operative time, estimated blood loss, and postoperative narcotic consumption on postoperative day 0 (P < 0.034, all). Mean PROMs differed significantly on 12-Item Short-Form Physical Component Summary at 6 weeks and 1 year, Patient-Reported Outcomes Measurement Information System Physical Function at 6 weeks, Oswestry Disability Index at 6 weeks, and visual analog scale (VAS) back at 6 weeks, with the ALIF cohort showing significantly improved mean PROMs (P ≤ 0.044, all). Significantly greater rates were reported of MCID achievement for PROMs for the ALIF cohort: VAS back at 6 weeks, Oswestry Disability Index at 12 weeks, 12-Item Short-Form Physical Component Summary at 6 weeks, and Patient-Reported Outcomes Measurement Information System Physical Function at 12 weeks (P ≤ 0.047, all). A greater rate of MCID achievement for the MIS-TLIF cohort was seen for 6-week and overall VAS leg (P < 0.046, all). Postoperative fever was greater in the TLIF cohort (9.6% vs. 2.0%; P < 0.047). Patients undergoing ALIF showed significantly improved rates of MCID achievement for disability, physical function, and back pain during the early postoperative period. However, the overall MCID achievement rate for leg pain was higher for the MIS-TLIF cohort. [ABSTRACT FROM AUTHOR]

Platinum group metals (PGMs) are precious rare metals mined only in a few regions of the world. Recycling PGMs used in automotive catalytic converters is of utmost importance to meet increasing global demand. The Rose process is the main recycling process used in Japan to recover PGMs from spent automotive catalytic converters. The recycling process involves smelting a ceramic structure, in which PGMs are supported, with Cu, Cu2O, reductants, and fluxes such as CaO and SiO2. This study compared the Pd and Pt recovery capability of Cu or Cu2O as extractants. Pd and Pt particles were simultaneously suspended in Al2O3CaOSiO2 molten slag, and the extractant Cu or Cu2O was added. The concentration of Pd and Pt in the slag as a function of processing time was investigated at 1723K of the operating temperature in the Rose process, under carbon saturation. The results show that the suspended Pd and Pt particles were combined by collisions in the slag, and the recovery ratio and recovery speed of Pd and Pt suspended particles were higher when using Cu2O than when using Cu. The Cu2O dissolved in the slag was reduced to metallic Cu in the slag and alloyed with the suspended PGMs particles to form Cu-PGMs alloys. As a result, the particle size of the PGMs increased and sedimentation motion in the slag is promoted. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Petroleum is becoming a limited commodity due to increasing global demands attributed to industrialization and the population boom. Because the conventional methods of oil recovery have exhaustively reached an economic limit, developing novel technological approaches in oil extraction is therefore a priority concern. One proposed strategy is the microbial enhanced oil recovery (MEOR), which is purported as an effective method to improve oil recovery from low-permeability reservoirs in China. Although this method is considered minimally invasive, low-cost, and operationally simple, it has not been widely applied in the oil industry. Here, we discuss the technical details of MEOR in laboratory settings and field tests. The current challenges in employing MEOR from lab settings to industrial pilot scale-ups are systematically presented, here, including its economic implications. Central to this review is the synopsis of our findings on the applicability of MEOR and micro-foam method in the northwest district of China (Shaanxi province), along with the successful cases of these applications in other countries. This article also focused on a newly developed flooding technology, the so-called genetically engineered microbial enhanced oil recovery (GEMEOR). In addition, we included our proposed operational designs on GEMEOR and its technological potentials on an industrial scale. This review therefore demonstrates the creditability of MEOR, and may provide more guidance for the application of GEMEOR in Chinese oilfields. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, a modified multiple effect distillation (MED) system will be studied for a minimal water footprint in the Algerian desert, as to preserve the aquifer and for a sustainable use of this later. In fact, the water footprint is the most important factor to take into consideration in the treatment of the brackish underground water in the Algerian desert to preserve this unique source of water. The modification of MED system consists on the change of the last water condenser of the unit for a hybrid condenser (water and air condenser). For this purpose, a MED system is studied for its high recovery ratio for brackish water treatment, its flexibility with different salt concentrations, its low thermal energy need, and its robustness. The results show that the introduction of a hybrid condenser in the system allows a minimal water footprint, which is expressed by the cooling water ratio running from 4 to 18 times less than a standard water condenser system. This new configuration is applicable for a top brine temperature ranging between 75°C to 100°C. Otherwise, for low-temperature MED, the total heat area of the system would reach twice the total heat area of a standard MED system. Finally, a nine effects standard MED system rejects six times the feed water quantity at a higher temperature than that of the aquifer’s from the last condenser and 4%–10% of brine. Whereas, the modified MED system will reject only 4%–10% of the brine at the end of the process and zero cooling water, which is a satisfactory result for a sustainable exploitation of the aquifer. [ABSTRACT FROM AUTHOR]

The recovery ratio of top coal blocks is the direct reflection of drawing effect in longwall top coal caving (LTCC), and predicting the field recovery rapidly and accurately is one of the leading difficult problems. We analyzed the relationship between the recovery and the relative size of top coal, and proposed a recovery prediction model (RPM) in the laboratory. We determined the measurement method of the top coal blocks size, and developed the field setup for measuring the recovery. In addition, we measured the relative size of top coal and the field recovery at four representative LTCC panels in China. The results show that in the laboratory RPM, with increasing relative size of top coal, the recovery increased first and then decreased. Employing the single-opening sequence caving in the panel, the recovery is the maximum when the value of the relative size of top coal is about 0.14. In the field, as thickness of top coal increased, the size distribution curves of top coal gradually changed from convex to concave, and the relative size of top coal gradually increased from 0.005 to 0.202. When the relative size of top coal is large, the recovery also increased and then decreased. However, the value of the field measured recovery is relatively small. When the relative size of top coal is equal to or greater than 0.079, the corrected field RPM can accurately predict the field recovery, verifying the accuracy of the field prediction model. RPM provides a new approach to estimate the recovery, which can greatly reduce the measurement cost and workload, as well as improve the measurement efficiency of recovery. [ABSTRACT FROM AUTHOR]

It is of great significance to find out the mutual interference mechanism between CBM drainage wells to rationally arrange well networks and improve CBM recovery. To this end, Lattice Boltzmann Method （LBM） was used to reproduce the migration process of CBM from cleat space to drainage wellhead, and the influence mechanism of different drainage parameters and mutual interference between CBM drainage wells on gas production were systematically analyzed. The results showed that the difference of gas production between wellbores showed fluctuation characteristics with the change of well spacing due to inter-well interference. If single well gas production was considered, inter-well interference had segmented effect on gas production. When the spacing of Ds between wells was less than 382.5 lu, it showed inhibiting effect; otherwise, it showed facilitation. Too small well spacing was not conducive to CBM production. When the well spacing exceeded the critical threshold of 382.5 lu, the recovery rate of CBM could be accelerated. The power law relationship ■≈3.2△p0.94 was followed by mean velocity ■ of CBM in wellhead and pressure difference △p.

The article's objective, which is to identify the causes of the very poor level of management of the administration of these state assets, to present the possibilities of a long-tested experimental model at the Land Fund of the Czech Republic, and to draw attention to this model's potential in its possible implementation in administration of the entire management complex of these state assets in the Czech Republic. The authors first dealt with the theoretical aspects of the given issue, and then prepared an analysis of the original debt collection management "system". This is logically followed by an analysis of the experimental model's efficiency, rounded off with its conclusions. The final chapter contains the results of the research aimed at the current level of knowledge of the examined issue in compressed form, further the outcomes of the research concerned with original unsystematic debt collection management, also results of the implementation of the experimental model, and the assessment of the significance belonging to the results of implementing the experimental model for the entire national economy of the Czech Republic.

We investigate the effectiveness of an integrated solar-driven system with a membrane-distillation process for freshwater production. A system is a self-powered unit that comprises a solar-photovoltaic system, solar-thermal system, and membrane-distillation system. A vacuum multi-effect membrane distillation (V-MEMD) module acts as the core of the solar desalination unit, and a heat pump is integrated to the module to improve its performance. We focus on evaluating the overall energy consumption, both thermal and electric, for the cases with and without condenser cooling. The system was tested in Riyadh over two seasons, that is, summers and winters. Upon enabling the preheat mode during June, March, and April, the maximum distillate-water production and the corresponding minimum specific electrical-energy consumption (SEEC) were achieved at approximately 31.8 L/h and 74.9 kWh/m3, respectively, for the overall system, and the SEEC for the V-MEMD unit also reached 6.3 kWh/m3. Furthermore, when the inlet heating (evaporator) temperature was greater than 55°C, cold-side absolute pressure was lower than 200 mbar, and preheat mode was active, then high water mass flux up to 12.2 kg/m2 h and recovery ratio up to 36.8% could be obtained. Moreover, the gain output ratio enhanced to 4.25. [ABSTRACT FROM AUTHOR]

The pore‐scale imbibition mechanism in fractured water‐wetted reservoirs has been acknowledged as an efficient tool to enhance oil recovery. Most rock in a natural reservoir is mixed‐wetted, but most studies on the pore‐scale imbibition process only focused on the water‐wetted rock. This paper adopts two mixed‐wetted core samples for microspontaneous imbibition experiment, micro‐CT scanning, and nuclear magnetic resonance (NMR) test. The results indicate that the pore radius distribution of the segmented CT images is consistent with that of the NMR test. The microimbibition recovery ratio of core No. 34‐1 and core No. 64 in the spontaneous imbibition experiment are 27.7% and 58.2%, which agrees well with that computed by the micro‐CT scanning image (27.63% and 56.09%). Based on the segmented images, the influences of the Jamin's effect, pore size distribution, and wettability on the microspontaneous imbibition are visualized and quantitatively studied. The Jamin's effect is the important factor that hinders the microimbibition process. The main pore size of imbibition distributes in the range of 1‐25 μm. Furthermore, the pore‐scale spontaneous imbibition process in a single pore with mixed wettability is investigated and analyzed. The relationships among the contact angle, capillary force, recovery ratio, wettability, and the microimbibition recovery are revealed. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

After polymer flooding treatment, the oil recovery can be enhanced through the application of advanced technology. However, in practical applications, excess residues will be generated after polymer flooding treatment. Therefore, in the analysis and treatment of residues, the distribution law of residues after polymer flooding is analyzed, and the recovery process and distribution treatment process are carried out. optimization to achieve enhanced oil recovery after polymer flooding. After the polymer flooding treatment, the high concentration and high molecular weight polymer treatment can improve the recovery rate of crude oil, and on the basis of the polymer flooding treatment, the polymer flooding effect can be improved, which can effectively improve the crude oil recovery rate. recovery and improve the development efficiency of oilfields.

In investigating the effect of biogenic gas production on the recovery of coalbed methane (CBM), coal samples spanning different ranks were applied in the microbial-functioned simulation experiments for biogenic methane production. Based on the biogenic methane yield, testing of pore structures, and the isothermal adsorption data of coals used before and after the simulation experiments, several key parameters related to the recovery of CBM, including recovery rate, gas saturation and ratio of critical desorption pressure to reservoir pressure, etc., were calculated and the corresponding variations were further analyzed. The results show that one of the significant functions of microbial communities on coal is possibly to weaken its affinity for methane gas, especially with the advance of coal ranks; and that by enhancing the pore system of coal, which can be evidenced by the increase of porosity and permeability, the samples collected from Qianqiu (Yima in Henan) and Shaqu (Liulin in Shanxi) coal mines all see a notable increase in the critical desorption pressure, gas saturation and recovery rate, as compared to the moderate changes of that of Guandi (Xishan in Shanxi) coal sample. It is concluded that the significance of enhanced biogenic gas is not only in the increase of CBM resources and the improvement of CBM recoverability, but in serving as an engineering reference for domestic coalbed biogenic gas production.