The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that o...The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that of conventional reservoirs.At the early stage of flowback,there is no single-phase flow of the liquid phase in shale,but rather a gas-water two-phase flow,such that the single-phase flow model for tight oil and gas reservoirs is not applicable.In this study,pores and microfractures are extracted based on the experimental results of computed tomography(CT)scanning,and a spatial model of microfractures is established.Then,the influence of rough microfracture surfaces on the flow is corrected using the modified cubic law,which was modified by introducing the average deviation of the microfracture height as a roughness factor to consider the influence of microfracture surface roughness.The flow in the fracture network is simulated using the modified cubic law and the lattice Boltzmann method(LBM).The results obtained demonstrate that most of the fracturing fluid is retained in the shale microfractures,which explains the low fracturing fluid flowback rate in shale hydraulic fracturing.展开更多
Almost all sandstone reservoirs contain interlayers. The identification and characterization of these interlayers iscritical for minimizing the uncertainty associated with oilfield development and improving oil and ga...Almost all sandstone reservoirs contain interlayers. The identification and characterization of these interlayers iscritical for minimizing the uncertainty associated with oilfield development and improving oil and gas recovery.Identifying interlayers outside wells using identification methods based on logging data and machine learning isdifficult and seismic-based identification techniques are expensive. Herein, a numerical model based on seepageand well-testing theories is introduced to identify interlayers using transient pressure data. The proposed modelrelies on the open-source MATLAB Reservoir Simulation Toolbox. The effects of the interlayer thickness, position,and width on the pressure response are thoroughly investigated. A procedure for inverting interlayer parametersin the reservoir using the bottom-hole pressure is also proposed. This method uses only transient pressuredata during well testing and can effectively identify the interlayer distribution near the wellbore at an extremelylow cost. The reliability of the model is verified using effective oilfield examples.展开更多
The identification and mitigation of anomaly data,characterized by deviations from normal patterns or singularities,stand as critical endeavors in modern technological landscapes,spanning domains such as Non-Fungible ...The identification and mitigation of anomaly data,characterized by deviations from normal patterns or singularities,stand as critical endeavors in modern technological landscapes,spanning domains such as Non-Fungible Tokens(NFTs),cyber-security,and the burgeoning metaverse.This paper presents a novel proposal aimed at refining anomaly detection methodologies,with a particular focus on continuous data streams.The essence of the proposed approach lies in analyzing the rate of change within such data streams,leveraging this dynamic aspect to discern anomalies with heightened precision and efficacy.Through empirical evaluation,our method demonstrates a marked improvement over existing techniques,showcasing more nuanced and sophisticated result values.Moreover,we envision a trajectory of continuous research and development,wherein iterative refinement and supplementation will tailor our approach to various anomaly detection scenarios,ensuring adaptability and robustness in real-world applications.展开更多
Due to the wide application of closely spaced multi-well horizontal pads for developing unconventional gas reservoirs,interference between wells becomes a significant concern.Communication between wells mainly occurs ...Due to the wide application of closely spaced multi-well horizontal pads for developing unconventional gas reservoirs,interference between wells becomes a significant concern.Communication between wells mainly occurs through natural fractures.However,previous studies have found that interwell communication through natural fractures is varied,and non-communication also appears in the mid and late stages of production due to natural fracture closure.This study proposes a boundary element method for coupling multi-connected regions for the first time.Using this method,we coupled multiple flow fields to establish dual-well models with various connectivity conditions of the stimulated reservoir volume(SRV)region.These models also take into consideration of adsorption and desorption mechanism of natural gas as well as the impact of fracturing fluid retention.The study found that when considering the non-communication of SRV regions between multi-well horizontal pads,the transient behavior of the targeted well exhibits a transitional flow stage occurring before the well interference flow stage.In addition,sensitivity analysis shows that the well spacing and production regime,as well as the connectivity conditions of the SRV region,affect the timing of interwell interference.Meanwhile,the productivity of the two wells,reservoir properties,and fracturing operations affect the intensity of interwell interference.展开更多
Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The p...Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The present study investigated the extent of pollution of sediments of this river and analyzed the regional variability for the concentrations of Cr, Pb, Zn, Cu and Cd—all of concern because of their potential toxicity, using atomic absorption spectrophotometer. As per US EPA sediment quality guideline, metal concentrations ranged between Cd: 0.00 - 0.80, Cr: 32.00 - 75.50, Cu: 46.30 - 60.00, Pb: 28.30 - 36.40, and Zn: 94.60 - 190.10 mg/kg in the Turag river sediments. Cr, Cu, Zn belongs to moderately to highly polluted, Pb and Cd belongs to not polluted for Turag river. The heavy metals contamination in the sediments were also evaluated by applying Index of geo-accumulation (Igeo), contamination factor (Cf), pollution load index (PLI) etc. Toxicity characteristics leaching procedure (TCLP) test (US EPA 1311) for sediment samples have been performed also for metals (Pb, Cd, Cr, Cu and Zn) to determine the readily toxicity level of heavy metals. Sieve analysis of sediment performed in this study to determine the physical characteristic of sediment samples. The metal concentrations are well below the regulated level as per US EPA. This index can be complemented with the contamination index, which allows more site-specific and accurate information on contaminant levels. If the aim of work on contamination evaluation is to assess the overall contamination of a study area, the indices are highly appropriate.展开更多
The aim of the present study was to evaluate the performance of Napier cultivars in terms of forage yield, plant morphology and nutrient contents under two different agro-ecology and geo-topographic conditions. Three ...The aim of the present study was to evaluate the performance of Napier cultivars in terms of forage yield, plant morphology and nutrient contents under two different agro-ecology and geo-topographic conditions. Three Napier cultivars being conserved by Bangladesh Livestock Research Institute (BLRI), namely-BLRI</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">Napier 1, (BN-1), BLRI</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">Napier 3 (BN-3) and Merkeron (BN-5) were selected to cultivate in severe drought prone areas (called Barind) and non-drought area at Savar (Modhupur terrace). Stem cuttings were planted in rows apart from 70 cm and 35cm spacing between plants. Data of 6 consecutive harvests from a period of approximately one year were collected and analyzed statistically by “R” software. The results showed that cultivar and location had </span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">significant (P < 0.001) effect on biomass yield, plant height and leaf-stem ratio (LSR), while number of tillers </span><span style="font-family:Verdana;">were </span><span style="font-family:Verdana;">significantly varied with locations. BN-3 yielded the highest biomass (33.32 t/ha/harvest) at non-drought location (42.98 t/ha/harvest). The highest plant height was obtained in BN-1 (171.2 cm) at non-drought location (174.6 cm). Number of tiller</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> per hill ranged from 25.4 to 26.3 among cultivars (P > 0.05) and the highest tillers were found at non-drought location (28.1 no). The best LSR was estimated from BN-5 (0.86) at drought location (0.95). The proximate analysis showed that CP, ADF and NDF in whole plant </span><span style="font-family:Verdana;">were </span><span style="font-family:Verdana;">varied significantly (P < 0.001), being the highest contents in BN-1 (10.69%, 46.20% and 54.58%, respectively). On the other hand, DM and ash contents did not differ significantly (P > 0.05) among cultivars which ranged from 15.80% to 17.13% and 13.10% to 14.58%, respectively. The highest CP content in whole plant was obtained at non-drought location (11.89%), while the lowest ash (10.57%) and NDF (52.71%) contents were obtained at the same location. The highest CP contents in leaf were found at non-drought (15.03%) and the lowest ash (9.86%) at the same location. The highest CP contents (5.90%) in stem were found at non-drought location, while the lowest ash (11.28%) and NDF (54.59%) contents </span><span style="font-family:Verdana;">were obtained </span><span style="font-family:Verdana;">at the same location. Finally, the experiment reveals the superiority in biomass yield and nutritional quality (in</span><span style="font-family:""> </span><span style="font-family:Verdana;">terms of CP content) with the ranking orders of BN-3 > BN-1 > BN-5 and BN-1 > BN-3 > BN-5. Therefore, it may be concluded that BN-1, BN-3</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> and BN-5 cultivars were well adapted in both drought and non-drought conditions, although performance showed better in later condition</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">. However, in terms of forage yield and overall nutrient composition, the performance of BN-3 was the best irrespective of locations.展开更多
Figuring out rock strength plays essential roles in the sub ground mining activities,such as oil and gas well drilling and hydraulic fracturing,coal mining,tunneling,and other civil engineering scenarios.To help under...Figuring out rock strength plays essential roles in the sub ground mining activities,such as oil and gas well drilling and hydraulic fracturing,coal mining,tunneling,and other civil engineering scenarios.To help understand the effects of the mineralogical composition on evaluating the rock strength,this research tries to establish indirect prediction models of rock strength by specific input mineral contents for common sedimentary rocks.Using rock samples collected from the outcrops in the Sichuan Basin,uniaxial compression tests have been conducted to sandstone,carbonate,and shale cores.Combining with statistical analysis,the experimental data prove it true that the mineralogical composition can be utilized to predict the rock strength under specific conditions but the effects of mineralogical composition on the rock strength highly depend on the rock lithologies.According to the statistical analysis results,the predicted values of rock strengths by the mineral contents can get high accuracies in sandstone and carbonate rocks while no evidences can be found in shale rocks.The best indicator for predicting rock strength should be the quartz content for the sandstone rocks and the dolomite content for the carbonate rocks.Especially,to improve the evaluation accuracy,the rock strengths of sandstones can be obtained by substituting the mineral contents of quartz and clays,and those of carbonates can be calculated by the mineral contents of dolomite and calcite.Noticeably,the research data point out a significant contrast of quartz content in evaluating the rock strength of the sandstone rocks and the carbonate rocks.Increasing quartz content helps increase the sandstone strength but decrease the carbonate strength.As for shale rocks,no relationship exists between the rock strength and the mineralogical composition(e.g.,the clay fractions).To provide more evidences,detailed discussion also provides the readers more glances into the framework of the rock matrix,which can be further studied in the future.These findings can help understand the effects of mineralogical composition on the rock strengths,explain the contrasts in the rock strength of the responses to the same mineral content(e.g.,the quartz content),and provide another indirect method for evaluating the rock strength of common sedimentary rocks.展开更多
This report presents the results of a study on Reproductive Health done in North Kivu in September 2009. It was conducted by HEAL Africa, in partnership with the Provisional Division of Health, and financed by the Uni...This report presents the results of a study on Reproductive Health done in North Kivu in September 2009. It was conducted by HEAL Africa, in partnership with the Provisional Division of Health, and financed by the University of Ottawa, Canada/CRDI with technical assistance from Western Cape University of South Africa. The study was conducted in the health zones of Birambizo and Kayna within the framework of the central office. The focus of the report is on one aspect of Reproductive Health—Low Risk Maternity. This study was conducted in rural areas given that Reproductive Health indicators are much weaker when compared with urban areas, according to EDS RDC, 2007 [1]. This study emphasizes the following points: General characteristics of the participants in the study, and the utilization and accessibility of maternity services in rural areas in conflict situations. The formula SPSS 12.0.1 was used to facilitate data analysis in the study. This study comes at a point in time when its relevance to HEAL Africa’s work will assist HEAL and its partners in determining the focus of interventions done in health zones in order to improve maternal and neonatal health. HEAL Africa firstly stepped into a Safe Motherhood pilot project in June 2006 for 9 months in the Masisi zone, then in 2007 in the Birambizo and Kayna health zones. In November 2007, HEAL expanded into Walikale and in October 2008, into Kirotshe, Binza, and Lubero. The intervention kit consists of reinforcing the capacity of existing health facilities, training traditional midwives who serve as a link between the community and the health structures, the provision of sanitary equipment, medical essentials and community mobilization was done through local leaders about health and reproduction, and organizing women of reproductive age in solidarity groups (SG) to generate maternity insurance. The community approach “Solidarity Groups for Maternity Insurance” constitutes the spine of HEAL Africa within the support it provides in Reproductive Health. The principal idea is to educate and train communities on how to use the MMR services that are available in their community, and to remove financial barriers to accessing health services. The 4 pillars that comprise the Safe Motherhood program are: family planning, prenatal care, safe assisted delivery and essential obstetric care. These four strategic measures are integral in assuring primary health care and equality for women. This study evaluates this approach, keeping in mind local strategies and their effects on improving the utilization and accessibility of reproductive health services.展开更多
This work was conducted to compare the potentiality between BLRI Napier-3(BN-3)and Pakchong(PK)fodders.In a completely randomized design(CRD)layout,10 plots(5 m′5 m each)were prepared and stem cuttings were transplan...This work was conducted to compare the potentiality between BLRI Napier-3(BN-3)and Pakchong(PK)fodders.In a completely randomized design(CRD)layout,10 plots(5 m′5 m each)were prepared and stem cuttings were transplanted.Fodder plants were harvested at 70,80 and 90 days after plantation(DAP)followed by making silage.Ten Red Chittagong Cattle(RCC)growing bull calves were selected and equally divided into two treatment groups fed only silages for nutrient utilization and growth evaluation.The highest biomass yield(69.3 ton/ha)and plant height(104.6 cm)were observed in PK at 90 DAP.The highest leaf weight(498.6 g/plant)and leaf to stem ratio(LSR)(1.53)were observed in BN-3 at 70 DAP,which was decreased gradually in progressing maturity.Conversely,stem weight was increased with progressing maturity.Dry matter(DM)(24.71%),total ash(8.35%)and acid detergent fiber(ADF)(61.89%)in PK silage were significantly higher.On the other hand,crude protein(CP)(9.86%),organic matter(OM)(91.65%)and neutral detergent fiber(NDF)(88.06%)in PK silage did not differ with BN-3 silage.Dry matter intake(DMI)and crude protein intake(CPI)from PK silage(2.25 kg/day/animal and 0.22 kg/day/animal)were significantly higher.Digestibility of DM(55.07%),CP(62.35%),OM(57.85%),total ash(30.89%),ADF(73.02%)and NDF(78.19%)for PK silage were significantly higher.N-intake(35.57 g/d)from PK silage was significantly higher,although,N-retention did not differ significantly.There were no significant differences in weight gain of calves fed PK(117 g/d)and BN-3(68 g/d).It can be concluded that PK silage is comparatively better than BN-3 in respect to biomass yield,digestibility and nutrient utilization in growing bull calves.展开更多
In the process of tunneling of tunnel boring machine (TBM), different geological conditions often correspond to different working conditions, and the randomness of geological conditions also causes the order of occurr...In the process of tunneling of tunnel boring machine (TBM), different geological conditions often correspond to different working conditions, and the randomness of geological conditions also causes the order of occurrence of each working condition to be different. Under the conversion of different working conditions, this makes the vibration of different types of cutterheads different. How to choose the appropriate type of cutterhead according to different geological conditions is very important for saving engineering cost and increasing cutterhead life. In view of the above situation, this paper proposes a stability evaluation method during the TBM tunneling process to select the appropriate cutterhead type. Firstly, the corresponding relationship between geology and working conditions is established according to different geological conditions, and the input loads corresponding to geological conditions are obtained. Then, it is substituted into the dynamic model of the cutterhead system, the vibration response boundaries of each degree of freedom are obtained by solving. And the average value of the maximum boundary amplitude of each degree of freedom is taken to represent the extreme vibration of the cutterhead under the corresponding working conditions. Finally, by comparing the fluctuation of the ultimate vibration amplitude of each type of cutterhead in the process of working condition conversion, the results are as follows: when the transition between homogeneous strata and composite strata is normal and there is no large turning and deviation correction, the vibration response of the two-part cutterhead is the smallest, and the two-part cutterhead is the best choice. Otherwise, the five-part cutterhead is the best choice, while the stability of the integrated cutterhead is the worst.展开更多
In response to the global food crisis and the imperative to address soil degradation, the international agricultural policy is actively working to alleviate the adverse impacts of soil salinity. As part of this initia...In response to the global food crisis and the imperative to address soil degradation, the international agricultural policy is actively working to alleviate the adverse impacts of soil salinity. As part of this initiative, a field trial spanning two consecutive seasons (2019/20-2020/21) was conducted under saline conditions. The primary objective was to evaluate the influence of various compost sources, including vermicompost at a rate of 0.5 ton·fed<sup>-1</sup> and plant residues compost at a rate of 5.0 ton·fed<sup>-1</sup>, as main plots. Subplots were established by applying agricultural gypsum, both in the presence and absence of gypsum requirements. Additionally, sub-subplots were created by externally applying cobalt at a rate of 10.0 mg·L<sup>-1</sup>, with one sub-subplot receiving foliar cobalt application and the other not. The trial sought to assess the growth performance, chemical composition, enzymatic antioxidants, yield, and quality of cabbage plants (Brassica oleracea var. capitata L.) cultivated in saline soil. According to the findings, cabbage plants exhibited the most favorable response in terms of plant height, chlorophyll content, carotene levels, leaf area, nitrogen (N), phosphorus (P), potassium (K), head yield, vitamin C, and total dissolved solids (TDS) when treated with vermicompost, followed by plant compost. Conversely, plants grown without compost exhibited the least improvement in performance. Cabbage treated with agricultural gypsum requirements showed better performance than those without gypsum amendment. Moreover, plants subjected to cobalt spray demonstrated the highest growth, yield, and quality parameters compared to those without cobalt foliar application. In contrast, the control group (plants without the studied treatments) displayed the highest levels of enzymatic antioxidants, specifically catalase and peroxidase. This indicates that soil salinity stress led to an increase in catalase and peroxidase production in cabbage plants as a defense against the harmful impact of reactive oxygen species (ROS) resulting from soil salinity stress. The applied treatments (compost, gypsum, and cobalt) led to a reduction in the cabbage plant’s inherent production of catalase and peroxidase. Generally, the combined treatment of vermicompost × gypsum requirements × cobalt proved effective in mitigating the detrimental effects of soil salinity on cabbage plants. These findings hold significance for farmers and policymakers aiming to enhance agricultural productivity in regions affected by soil salinity. Additionally, further research can explore the long-term effects of these treatments on soil health and crop sustainability.展开更多
Accurate prediction of natural gas well production data is crucial for effective resource management and innovation,particularly amid the global transition to sustainable energy.Traditional models struggle with high-f...Accurate prediction of natural gas well production data is crucial for effective resource management and innovation,particularly amid the global transition to sustainable energy.Traditional models struggle with high-frequency,high-dimensional datasets generated by digital transformation in the oil and gas industry.This study explores the application of Transformer-based models—Transformer,Informer,Autoformer,and Patch Time Series Transformer(PatchTST)—for forecasting high-frequency natural gas production data.These models utilize self-attention mechanisms to capture long-term dependencies and efficiently process large-scale datasets.Autoformer achieves predictive success through its Seasonal Decomposition Attention mechanism,which effectively extracts trend-seasonality patterns.However,our experiments show that Autoformer exhibits sensitivity to dataset changes,as performance declines when using old parameters compared to retrained models,highlighting its reliance on dataset-specific retraining.Experimental results demonstrate that increasing sampling frequency significantly enhances prediction accuracy,reducing MAPE from 0.556 to 0.239.Additionally,these models consistently track actual production trends across extended forecast horizons.Notably,PatchTST maintains stable performance using either pretrained or retrained parameters,showcasing superior adaptability and generalization.This makes it particularly suitable for real-world applications where frequent retraining may not be feasible.Overall,the findings validate the applicability of Transformer-based models,particularly PatchTST,in dynamic and precise natural gas production forecasting.This study provides valuable insights for advancing adaptive,data-driven resource management strategies.展开更多
Speed–flow functions have been developed by several transportation experts to predict accurately the speed of urban road networks.HCM Speed-Flow Curve,BPR Curve,MTC Speed-Flow Curve,Akçelik Speed-Flow Curve are ...Speed–flow functions have been developed by several transportation experts to predict accurately the speed of urban road networks.HCM Speed-Flow Curve,BPR Curve,MTC Speed-Flow Curve,Akçelik Speed-Flow Curve are some extraordinary efforts to define the shape of speedflow curves.However,the complexity of driver’s behaviour,interactions among different type of vehicles,lateral clearance,co-relation of driver’s psychology with vehicular characteristics and interdependence of various variables of traffic has led to continuous development and refinement of speed-flow curves.The problem gets more difficult in the case of urban roads with heterogeneous traffic,oversaturated flow and signalized network(which includes some unsignalized intersections as well).This paper presents analysis for various measures of effectiveness(MOE)for urban roads with interrupted flow comprising heterogeneous traffic.Model has been developed for heterogeneous traffic under constraints of roadway geometry,vehicle characteristics,driving behaviour and traffic controls.The model developed in this paper predicts speed,delay,average queue and maximum queue estimates for urban roads and quantifies congestion for oversaturated conditions.The investigation details the oversaturated portion of flow in particular.展开更多
Bus Rapid Transit(BRT)has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance.The rapid transit fe...Bus Rapid Transit(BRT)has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance.The rapid transit feature of BRT is seen as a solution to many traffic problems in these countries.However,in developing countries like India,the right–of-way for most of the roads is restricted and traffic is heterogeneous in nature.Provision of BRT in existing right–ofway reduces the capacity available for other motorized traffic.As the buses travel with a certain frequency on dedicated bus-ways,the dedicated corridor remains unused for most of the period when other traffic on motorized vehicle(MV)lanes suffers from congestion.The problem gets severe at intersections.However,if buses are operated in mixed traffic it is no more rapid transit.Hence,a solution is required to address this problem and optimize the performance of traffic as a whole.This paper presents the effect if dedicated bus-ways end at a reasonable distance before the stop line at a busy signalized at-grade intersection,and bus lanes(beyond that)are made available to all the motorized vehicular traffic(heterogeneous traffic)at intersection.The performance evaluation is done in terms of average queue length,maximum queue length,average delay time per vehicle,vehicle throughput,average speed in network and emission of Carbon monoxide CO,mono-nitrogen oxides NOx and Volatile organic compounds(VOC).It is observed that availability of bus lanes to other motorized traffic for a reasonable distance before intersection considerably reduces the average queue length,maximum queue length,average delay time per vehicle and emission per vehicle,while there is an increase in vehicle throughput and average speed of all the vehicles in the network.Thus it results in reduction of congestion and performance enhancement of at-grade intersections and network.Results of investigation are relevant in international context.VISSIM,a microscopic simulation tool,is used to model the heterogeneous traffic and public transit lines under constraints of roadway geometry,vehicle characteristics,driving behaviour and traffic controls.The effect is investigated with different random seeds to obtain reasonable results for analysis.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52022087).
文摘The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that of conventional reservoirs.At the early stage of flowback,there is no single-phase flow of the liquid phase in shale,but rather a gas-water two-phase flow,such that the single-phase flow model for tight oil and gas reservoirs is not applicable.In this study,pores and microfractures are extracted based on the experimental results of computed tomography(CT)scanning,and a spatial model of microfractures is established.Then,the influence of rough microfracture surfaces on the flow is corrected using the modified cubic law,which was modified by introducing the average deviation of the microfracture height as a roughness factor to consider the influence of microfracture surface roughness.The flow in the fracture network is simulated using the modified cubic law and the lattice Boltzmann method(LBM).The results obtained demonstrate that most of the fracturing fluid is retained in the shale microfractures,which explains the low fracturing fluid flowback rate in shale hydraulic fracturing.
文摘Almost all sandstone reservoirs contain interlayers. The identification and characterization of these interlayers iscritical for minimizing the uncertainty associated with oilfield development and improving oil and gas recovery.Identifying interlayers outside wells using identification methods based on logging data and machine learning isdifficult and seismic-based identification techniques are expensive. Herein, a numerical model based on seepageand well-testing theories is introduced to identify interlayers using transient pressure data. The proposed modelrelies on the open-source MATLAB Reservoir Simulation Toolbox. The effects of the interlayer thickness, position,and width on the pressure response are thoroughly investigated. A procedure for inverting interlayer parametersin the reservoir using the bottom-hole pressure is also proposed. This method uses only transient pressuredata during well testing and can effectively identify the interlayer distribution near the wellbore at an extremelylow cost. The reliability of the model is verified using effective oilfield examples.
基金supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea(NRF-2019S1A5B5A02041334).
文摘The identification and mitigation of anomaly data,characterized by deviations from normal patterns or singularities,stand as critical endeavors in modern technological landscapes,spanning domains such as Non-Fungible Tokens(NFTs),cyber-security,and the burgeoning metaverse.This paper presents a novel proposal aimed at refining anomaly detection methodologies,with a particular focus on continuous data streams.The essence of the proposed approach lies in analyzing the rate of change within such data streams,leveraging this dynamic aspect to discern anomalies with heightened precision and efficacy.Through empirical evaluation,our method demonstrates a marked improvement over existing techniques,showcasing more nuanced and sophisticated result values.Moreover,we envision a trajectory of continuous research and development,wherein iterative refinement and supplementation will tailor our approach to various anomaly detection scenarios,ensuring adaptability and robustness in real-world applications.
基金supported by the National Science Fund for Excellent Young Scholars(No.52222402)State Key Program of National Natural Science Foundation of China(No.U23A2022)+7 种基金State Key Program of National Natural Science Foundation of China(No.52234003)Sichuan Science and Technology Program(No.2022JDJQ0009)National Natural Science Foundation of China(No.52074235)Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(Nos.2020CX020202 and 2020CX030202)Shale Gas industry Development Institute of Sichuan Province111 Project(No.D18016)China Postdoctoral Science Foundation(No.2022M722637)the Science Foundation of Sichuan Province(No.2022NSFSC0186)。
文摘Due to the wide application of closely spaced multi-well horizontal pads for developing unconventional gas reservoirs,interference between wells becomes a significant concern.Communication between wells mainly occurs through natural fractures.However,previous studies have found that interwell communication through natural fractures is varied,and non-communication also appears in the mid and late stages of production due to natural fracture closure.This study proposes a boundary element method for coupling multi-connected regions for the first time.Using this method,we coupled multiple flow fields to establish dual-well models with various connectivity conditions of the stimulated reservoir volume(SRV)region.These models also take into consideration of adsorption and desorption mechanism of natural gas as well as the impact of fracturing fluid retention.The study found that when considering the non-communication of SRV regions between multi-well horizontal pads,the transient behavior of the targeted well exhibits a transitional flow stage occurring before the well interference flow stage.In addition,sensitivity analysis shows that the well spacing and production regime,as well as the connectivity conditions of the SRV region,affect the timing of interwell interference.Meanwhile,the productivity of the two wells,reservoir properties,and fracturing operations affect the intensity of interwell interference.
文摘Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The present study investigated the extent of pollution of sediments of this river and analyzed the regional variability for the concentrations of Cr, Pb, Zn, Cu and Cd—all of concern because of their potential toxicity, using atomic absorption spectrophotometer. As per US EPA sediment quality guideline, metal concentrations ranged between Cd: 0.00 - 0.80, Cr: 32.00 - 75.50, Cu: 46.30 - 60.00, Pb: 28.30 - 36.40, and Zn: 94.60 - 190.10 mg/kg in the Turag river sediments. Cr, Cu, Zn belongs to moderately to highly polluted, Pb and Cd belongs to not polluted for Turag river. The heavy metals contamination in the sediments were also evaluated by applying Index of geo-accumulation (Igeo), contamination factor (Cf), pollution load index (PLI) etc. Toxicity characteristics leaching procedure (TCLP) test (US EPA 1311) for sediment samples have been performed also for metals (Pb, Cd, Cr, Cu and Zn) to determine the readily toxicity level of heavy metals. Sieve analysis of sediment performed in this study to determine the physical characteristic of sediment samples. The metal concentrations are well below the regulated level as per US EPA. This index can be complemented with the contamination index, which allows more site-specific and accurate information on contaminant levels. If the aim of work on contamination evaluation is to assess the overall contamination of a study area, the indices are highly appropriate.
文摘The aim of the present study was to evaluate the performance of Napier cultivars in terms of forage yield, plant morphology and nutrient contents under two different agro-ecology and geo-topographic conditions. Three Napier cultivars being conserved by Bangladesh Livestock Research Institute (BLRI), namely-BLRI</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">Napier 1, (BN-1), BLRI</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">Napier 3 (BN-3) and Merkeron (BN-5) were selected to cultivate in severe drought prone areas (called Barind) and non-drought area at Savar (Modhupur terrace). Stem cuttings were planted in rows apart from 70 cm and 35cm spacing between plants. Data of 6 consecutive harvests from a period of approximately one year were collected and analyzed statistically by “R” software. The results showed that cultivar and location had </span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">significant (P < 0.001) effect on biomass yield, plant height and leaf-stem ratio (LSR), while number of tillers </span><span style="font-family:Verdana;">were </span><span style="font-family:Verdana;">significantly varied with locations. BN-3 yielded the highest biomass (33.32 t/ha/harvest) at non-drought location (42.98 t/ha/harvest). The highest plant height was obtained in BN-1 (171.2 cm) at non-drought location (174.6 cm). Number of tiller</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> per hill ranged from 25.4 to 26.3 among cultivars (P > 0.05) and the highest tillers were found at non-drought location (28.1 no). The best LSR was estimated from BN-5 (0.86) at drought location (0.95). The proximate analysis showed that CP, ADF and NDF in whole plant </span><span style="font-family:Verdana;">were </span><span style="font-family:Verdana;">varied significantly (P < 0.001), being the highest contents in BN-1 (10.69%, 46.20% and 54.58%, respectively). On the other hand, DM and ash contents did not differ significantly (P > 0.05) among cultivars which ranged from 15.80% to 17.13% and 13.10% to 14.58%, respectively. The highest CP content in whole plant was obtained at non-drought location (11.89%), while the lowest ash (10.57%) and NDF (52.71%) contents were obtained at the same location. The highest CP contents in leaf were found at non-drought (15.03%) and the lowest ash (9.86%) at the same location. The highest CP contents (5.90%) in stem were found at non-drought location, while the lowest ash (11.28%) and NDF (54.59%) contents </span><span style="font-family:Verdana;">were obtained </span><span style="font-family:Verdana;">at the same location. Finally, the experiment reveals the superiority in biomass yield and nutritional quality (in</span><span style="font-family:""> </span><span style="font-family:Verdana;">terms of CP content) with the ranking orders of BN-3 > BN-1 > BN-5 and BN-1 > BN-3 > BN-5. Therefore, it may be concluded that BN-1, BN-3</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> and BN-5 cultivars were well adapted in both drought and non-drought conditions, although performance showed better in later condition</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">. However, in terms of forage yield and overall nutrient composition, the performance of BN-3 was the best irrespective of locations.
基金supported by National Key Research and Development Program of China(2019YFA0708302)National Natural Science Foundation of China(Grant No.52004296,and Grant No.52274016)+1 种基金the Foundation of State Key Laboratory of Petroleum Resources and Prospecting(PRP/DX-2206)Science Foundation of China University of Petroleum-Beijing(No.2462022YXZZ007,No.2462022BJRC012).
文摘Figuring out rock strength plays essential roles in the sub ground mining activities,such as oil and gas well drilling and hydraulic fracturing,coal mining,tunneling,and other civil engineering scenarios.To help understand the effects of the mineralogical composition on evaluating the rock strength,this research tries to establish indirect prediction models of rock strength by specific input mineral contents for common sedimentary rocks.Using rock samples collected from the outcrops in the Sichuan Basin,uniaxial compression tests have been conducted to sandstone,carbonate,and shale cores.Combining with statistical analysis,the experimental data prove it true that the mineralogical composition can be utilized to predict the rock strength under specific conditions but the effects of mineralogical composition on the rock strength highly depend on the rock lithologies.According to the statistical analysis results,the predicted values of rock strengths by the mineral contents can get high accuracies in sandstone and carbonate rocks while no evidences can be found in shale rocks.The best indicator for predicting rock strength should be the quartz content for the sandstone rocks and the dolomite content for the carbonate rocks.Especially,to improve the evaluation accuracy,the rock strengths of sandstones can be obtained by substituting the mineral contents of quartz and clays,and those of carbonates can be calculated by the mineral contents of dolomite and calcite.Noticeably,the research data point out a significant contrast of quartz content in evaluating the rock strength of the sandstone rocks and the carbonate rocks.Increasing quartz content helps increase the sandstone strength but decrease the carbonate strength.As for shale rocks,no relationship exists between the rock strength and the mineralogical composition(e.g.,the clay fractions).To provide more evidences,detailed discussion also provides the readers more glances into the framework of the rock matrix,which can be further studied in the future.These findings can help understand the effects of mineralogical composition on the rock strengths,explain the contrasts in the rock strength of the responses to the same mineral content(e.g.,the quartz content),and provide another indirect method for evaluating the rock strength of common sedimentary rocks.
文摘This report presents the results of a study on Reproductive Health done in North Kivu in September 2009. It was conducted by HEAL Africa, in partnership with the Provisional Division of Health, and financed by the University of Ottawa, Canada/CRDI with technical assistance from Western Cape University of South Africa. The study was conducted in the health zones of Birambizo and Kayna within the framework of the central office. The focus of the report is on one aspect of Reproductive Health—Low Risk Maternity. This study was conducted in rural areas given that Reproductive Health indicators are much weaker when compared with urban areas, according to EDS RDC, 2007 [1]. This study emphasizes the following points: General characteristics of the participants in the study, and the utilization and accessibility of maternity services in rural areas in conflict situations. The formula SPSS 12.0.1 was used to facilitate data analysis in the study. This study comes at a point in time when its relevance to HEAL Africa’s work will assist HEAL and its partners in determining the focus of interventions done in health zones in order to improve maternal and neonatal health. HEAL Africa firstly stepped into a Safe Motherhood pilot project in June 2006 for 9 months in the Masisi zone, then in 2007 in the Birambizo and Kayna health zones. In November 2007, HEAL expanded into Walikale and in October 2008, into Kirotshe, Binza, and Lubero. The intervention kit consists of reinforcing the capacity of existing health facilities, training traditional midwives who serve as a link between the community and the health structures, the provision of sanitary equipment, medical essentials and community mobilization was done through local leaders about health and reproduction, and organizing women of reproductive age in solidarity groups (SG) to generate maternity insurance. The community approach “Solidarity Groups for Maternity Insurance” constitutes the spine of HEAL Africa within the support it provides in Reproductive Health. The principal idea is to educate and train communities on how to use the MMR services that are available in their community, and to remove financial barriers to accessing health services. The 4 pillars that comprise the Safe Motherhood program are: family planning, prenatal care, safe assisted delivery and essential obstetric care. These four strategic measures are integral in assuring primary health care and equality for women. This study evaluates this approach, keeping in mind local strategies and their effects on improving the utilization and accessibility of reproductive health services.
文摘This work was conducted to compare the potentiality between BLRI Napier-3(BN-3)and Pakchong(PK)fodders.In a completely randomized design(CRD)layout,10 plots(5 m′5 m each)were prepared and stem cuttings were transplanted.Fodder plants were harvested at 70,80 and 90 days after plantation(DAP)followed by making silage.Ten Red Chittagong Cattle(RCC)growing bull calves were selected and equally divided into two treatment groups fed only silages for nutrient utilization and growth evaluation.The highest biomass yield(69.3 ton/ha)and plant height(104.6 cm)were observed in PK at 90 DAP.The highest leaf weight(498.6 g/plant)and leaf to stem ratio(LSR)(1.53)were observed in BN-3 at 70 DAP,which was decreased gradually in progressing maturity.Conversely,stem weight was increased with progressing maturity.Dry matter(DM)(24.71%),total ash(8.35%)and acid detergent fiber(ADF)(61.89%)in PK silage were significantly higher.On the other hand,crude protein(CP)(9.86%),organic matter(OM)(91.65%)and neutral detergent fiber(NDF)(88.06%)in PK silage did not differ with BN-3 silage.Dry matter intake(DMI)and crude protein intake(CPI)from PK silage(2.25 kg/day/animal and 0.22 kg/day/animal)were significantly higher.Digestibility of DM(55.07%),CP(62.35%),OM(57.85%),total ash(30.89%),ADF(73.02%)and NDF(78.19%)for PK silage were significantly higher.N-intake(35.57 g/d)from PK silage was significantly higher,although,N-retention did not differ significantly.There were no significant differences in weight gain of calves fed PK(117 g/d)and BN-3(68 g/d).It can be concluded that PK silage is comparatively better than BN-3 in respect to biomass yield,digestibility and nutrient utilization in growing bull calves.
基金National Natural Science Foundation of China(Grant No. 51875076) NSFC-Liaoning United Key fund (Grant No. U1708255).
文摘In the process of tunneling of tunnel boring machine (TBM), different geological conditions often correspond to different working conditions, and the randomness of geological conditions also causes the order of occurrence of each working condition to be different. Under the conversion of different working conditions, this makes the vibration of different types of cutterheads different. How to choose the appropriate type of cutterhead according to different geological conditions is very important for saving engineering cost and increasing cutterhead life. In view of the above situation, this paper proposes a stability evaluation method during the TBM tunneling process to select the appropriate cutterhead type. Firstly, the corresponding relationship between geology and working conditions is established according to different geological conditions, and the input loads corresponding to geological conditions are obtained. Then, it is substituted into the dynamic model of the cutterhead system, the vibration response boundaries of each degree of freedom are obtained by solving. And the average value of the maximum boundary amplitude of each degree of freedom is taken to represent the extreme vibration of the cutterhead under the corresponding working conditions. Finally, by comparing the fluctuation of the ultimate vibration amplitude of each type of cutterhead in the process of working condition conversion, the results are as follows: when the transition between homogeneous strata and composite strata is normal and there is no large turning and deviation correction, the vibration response of the two-part cutterhead is the smallest, and the two-part cutterhead is the best choice. Otherwise, the five-part cutterhead is the best choice, while the stability of the integrated cutterhead is the worst.
文摘In response to the global food crisis and the imperative to address soil degradation, the international agricultural policy is actively working to alleviate the adverse impacts of soil salinity. As part of this initiative, a field trial spanning two consecutive seasons (2019/20-2020/21) was conducted under saline conditions. The primary objective was to evaluate the influence of various compost sources, including vermicompost at a rate of 0.5 ton·fed<sup>-1</sup> and plant residues compost at a rate of 5.0 ton·fed<sup>-1</sup>, as main plots. Subplots were established by applying agricultural gypsum, both in the presence and absence of gypsum requirements. Additionally, sub-subplots were created by externally applying cobalt at a rate of 10.0 mg·L<sup>-1</sup>, with one sub-subplot receiving foliar cobalt application and the other not. The trial sought to assess the growth performance, chemical composition, enzymatic antioxidants, yield, and quality of cabbage plants (Brassica oleracea var. capitata L.) cultivated in saline soil. According to the findings, cabbage plants exhibited the most favorable response in terms of plant height, chlorophyll content, carotene levels, leaf area, nitrogen (N), phosphorus (P), potassium (K), head yield, vitamin C, and total dissolved solids (TDS) when treated with vermicompost, followed by plant compost. Conversely, plants grown without compost exhibited the least improvement in performance. Cabbage treated with agricultural gypsum requirements showed better performance than those without gypsum amendment. Moreover, plants subjected to cobalt spray demonstrated the highest growth, yield, and quality parameters compared to those without cobalt foliar application. In contrast, the control group (plants without the studied treatments) displayed the highest levels of enzymatic antioxidants, specifically catalase and peroxidase. This indicates that soil salinity stress led to an increase in catalase and peroxidase production in cabbage plants as a defense against the harmful impact of reactive oxygen species (ROS) resulting from soil salinity stress. The applied treatments (compost, gypsum, and cobalt) led to a reduction in the cabbage plant’s inherent production of catalase and peroxidase. Generally, the combined treatment of vermicompost × gypsum requirements × cobalt proved effective in mitigating the detrimental effects of soil salinity on cabbage plants. These findings hold significance for farmers and policymakers aiming to enhance agricultural productivity in regions affected by soil salinity. Additionally, further research can explore the long-term effects of these treatments on soil health and crop sustainability.
基金support of the Na-tional Natural Science Foundation of China(Grant Nos.52376159 and 52474064)the Frontier Interdisciplinary Exploration Re-search Program of China University of Petroleum,Beijing(Grant No.2462024XKQY005)。
文摘Accurate prediction of natural gas well production data is crucial for effective resource management and innovation,particularly amid the global transition to sustainable energy.Traditional models struggle with high-frequency,high-dimensional datasets generated by digital transformation in the oil and gas industry.This study explores the application of Transformer-based models—Transformer,Informer,Autoformer,and Patch Time Series Transformer(PatchTST)—for forecasting high-frequency natural gas production data.These models utilize self-attention mechanisms to capture long-term dependencies and efficiently process large-scale datasets.Autoformer achieves predictive success through its Seasonal Decomposition Attention mechanism,which effectively extracts trend-seasonality patterns.However,our experiments show that Autoformer exhibits sensitivity to dataset changes,as performance declines when using old parameters compared to retrained models,highlighting its reliance on dataset-specific retraining.Experimental results demonstrate that increasing sampling frequency significantly enhances prediction accuracy,reducing MAPE from 0.556 to 0.239.Additionally,these models consistently track actual production trends across extended forecast horizons.Notably,PatchTST maintains stable performance using either pretrained or retrained parameters,showcasing superior adaptability and generalization.This makes it particularly suitable for real-world applications where frequent retraining may not be feasible.Overall,the findings validate the applicability of Transformer-based models,particularly PatchTST,in dynamic and precise natural gas production forecasting.This study provides valuable insights for advancing adaptive,data-driven resource management strategies.
文摘Speed–flow functions have been developed by several transportation experts to predict accurately the speed of urban road networks.HCM Speed-Flow Curve,BPR Curve,MTC Speed-Flow Curve,Akçelik Speed-Flow Curve are some extraordinary efforts to define the shape of speedflow curves.However,the complexity of driver’s behaviour,interactions among different type of vehicles,lateral clearance,co-relation of driver’s psychology with vehicular characteristics and interdependence of various variables of traffic has led to continuous development and refinement of speed-flow curves.The problem gets more difficult in the case of urban roads with heterogeneous traffic,oversaturated flow and signalized network(which includes some unsignalized intersections as well).This paper presents analysis for various measures of effectiveness(MOE)for urban roads with interrupted flow comprising heterogeneous traffic.Model has been developed for heterogeneous traffic under constraints of roadway geometry,vehicle characteristics,driving behaviour and traffic controls.The model developed in this paper predicts speed,delay,average queue and maximum queue estimates for urban roads and quantifies congestion for oversaturated conditions.The investigation details the oversaturated portion of flow in particular.
文摘Bus Rapid Transit(BRT)has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance.The rapid transit feature of BRT is seen as a solution to many traffic problems in these countries.However,in developing countries like India,the right–of-way for most of the roads is restricted and traffic is heterogeneous in nature.Provision of BRT in existing right–ofway reduces the capacity available for other motorized traffic.As the buses travel with a certain frequency on dedicated bus-ways,the dedicated corridor remains unused for most of the period when other traffic on motorized vehicle(MV)lanes suffers from congestion.The problem gets severe at intersections.However,if buses are operated in mixed traffic it is no more rapid transit.Hence,a solution is required to address this problem and optimize the performance of traffic as a whole.This paper presents the effect if dedicated bus-ways end at a reasonable distance before the stop line at a busy signalized at-grade intersection,and bus lanes(beyond that)are made available to all the motorized vehicular traffic(heterogeneous traffic)at intersection.The performance evaluation is done in terms of average queue length,maximum queue length,average delay time per vehicle,vehicle throughput,average speed in network and emission of Carbon monoxide CO,mono-nitrogen oxides NOx and Volatile organic compounds(VOC).It is observed that availability of bus lanes to other motorized traffic for a reasonable distance before intersection considerably reduces the average queue length,maximum queue length,average delay time per vehicle and emission per vehicle,while there is an increase in vehicle throughput and average speed of all the vehicles in the network.Thus it results in reduction of congestion and performance enhancement of at-grade intersections and network.Results of investigation are relevant in international context.VISSIM,a microscopic simulation tool,is used to model the heterogeneous traffic and public transit lines under constraints of roadway geometry,vehicle characteristics,driving behaviour and traffic controls.The effect is investigated with different random seeds to obtain reasonable results for analysis.
