Hydraulic fracturing has been widely applied in shale gas exploitation because it improves the permeability of the rock matrix.Fracturing stimulation parameters such as the pumping rate, the fracturing sequence, and t...Hydraulic fracturing has been widely applied in shale gas exploitation because it improves the permeability of the rock matrix.Fracturing stimulation parameters such as the pumping rate, the fracturing sequence, and the fracture spacing significantly influence the distribution of the stimulated reservoir volume(SRV). In this research, we built a numerical model that incorporates the hydraulic fracturing process and predicts gas production. The simulation of fracture propagation is based on the extended finite element method(XFEM), which helps to calculate aspects of the fractures and the SRV; we imported the results into a production analysis model as the initial conditions for production prediction. Using the model, we investigated the effects of some key parameters such as rock cohesion, fracture spacing, pumping rate, and fracturing sequence on the shale gas production.Our results proved that the SRV was distributed in the vicinity of the main fractures, and the SRVs were connected between the fractures in a small fracture spacing. We obtained optimal spacing by analyzing the production increment. High pumping-rate treatment greatly changes the in-situ stress around the hydraulic fractures and enlarges the field of SRV. Simultaneous fracturing treatment improves the flow conductivity of formation more than sequential fracturing. This study provides insights into the hydraulic fracturing design for economical production.展开更多
The study of microbial communities in the produced water of coalbed methane(CBM)wells is an important aspect of microbial-enhanced methane production.Water produced from 15 CBM wells in four synclines in eastern Yunna...The study of microbial communities in the produced water of coalbed methane(CBM)wells is an important aspect of microbial-enhanced methane production.Water produced from 15 CBM wells in four synclines in eastern Yunnan and western Guizhou was collected.Through the use of 16S ribosomal RNA(16S rRNA)amplicon sequencing and realtime fluorescence quantitative polymerase chain reaction(PCR),the characteristics of bacterial and archaeal communities before and after enrichment culture were studied.The methanogenic pathways of secondary biogas were discussed,and potential microbial-enhanced methane production was preliminarily evaluated.The results showed that the bacterial DNA content in uncultured produced water was low,so it is difficult to detect.After enrichment,the dominant bacteria phyla were Proteobacteria,Bacteroidetes,and Firmicutes.A total of seven phyla were detected in the uncultured produced water,and the dominant archaeal phylum was Euyarchaeota.Methanogens were the main component of archaea.The dominant archaeal genera were Methanobacterium,Methanoculleus and Methanobrevibacter.The community structure of the archaea changed noticeably after four days of enrichment culture.The relative abundance of Euryarchaeota increased to 99%in most samples after enrichment culture.It was found that there was a transition from Methanoregula to Methanobacterium within genera.The relative abundance of Methanobacterium increased,which can produce hydrogenotrophic methane.Combined with the isotopic composition of the produced water and gas,it is considered that the CBM in the Tucheng and Enhong synlines consists of a mixture of thermogenic gas and biogas.The proportion of secondary biogas in the Tucheng and Enhong synlines are estimated to range from 10.89% to 49.62%.There are mainly hydrogentrophic methanogens in the study area,and CO_(2) reduction is the main way of microbial gas production.After enrichment culture of produced water in the study area,the hydrogenotrophic methanogens were enriched.These two areas have stro展开更多
Oligomycins are a group of 26 macrocyclic lactones that exhibit broad biological activities,including antifungal,anticancer and nematocidal activities.Analysis of the oligomycin biosynthetic gene cluster (olm) in S.av...Oligomycins are a group of 26 macrocyclic lactones that exhibit broad biological activities,including antifungal,anticancer and nematocidal activities.Analysis of the oligomycin biosynthetic gene cluster (olm) in S.avermitilis revealed 2 tandem LuxR-type regulators,OlmRI (931 aa) and OlmRII (941 aa),with shared identity of 38%.Gene replacement of olmRI or olmRII abolished oligomycin production,and this production could be partially restored in the disruptants by introducing cloned olmRI and olmRII with their native promoters,demonstrating the essential role of OlmRI and OlmRII for oligomycin biosynthesis.Quantitative real-time RT-PCR analysis revealed that transcription of 14 olm genes was differentially affected by the deletion of olmRI and olmRII.Unexpectedly,avermectin production in both mutants was enhanced at least 4-fold.The identification of the positive cluster-situated regulators,OlmRI and OlmRII,paves the way for the transcriptional analysis of oligomycin biosynthesis and for the enhancement of oligomycin and avermectin production through regulator engineering.展开更多
Conventionally oil recovery factor is too low,which leaves great prospects for the application of enhanced oil recovery(EOR)methods to increase recovery factor.EOR methods are capital intensive and few are environment...Conventionally oil recovery factor is too low,which leaves great prospects for the application of enhanced oil recovery(EOR)methods to increase recovery factor.EOR methods are capital intensive and few are environmentally hazardous.So the paper discusses on the alternate enhanced oil recovery technique which has tremendous potential to curb the challenges of conventional EOR methods.Plasma pulse technology(PPT)aided EOR treatment is administered with an electric wireline conveyed plasma pulse generator tool that is run in the well and positioned alongside the perforations.Using energy stored in the generator's capacitors,a plasma arc is created that emits a tremendous amount of heat and pressure for a fraction of a second.This in turn creates a broad band of hydraulic impulse acoustic waves that are powerful enough to clean perforations and near wellbore damage.These waves continue to resonate deep into the reservoir,exciting the fluid molecules and increasing the reservoirs natural resonance to the degree that it can break larger hydrocarbon molecules to smaller one and simultaneously reducing adhesion tension which results in increased mobility of hydrocarbons.The plasma pulse technology has been successfully used on production as well as injection wells.It has been used often as a remedial procedure to increase well's productivity that has been on production for a period of time.This paper throws light on fundamentals of this advancing plasma pulse technology,contrasting it with recent EOR techniques.Effectiveness of treatment in increasing oil recovery,it's applicability to different reservoir types and results achieved so far are also covered in the paper.展开更多
Hydrogen is an indispensable energy carrier for the sustainable development of human society.Nevertheless,its storage,transportation,and in situ generation still face significant challenges.Methanol can be used as an ...Hydrogen is an indispensable energy carrier for the sustainable development of human society.Nevertheless,its storage,transportation,and in situ generation still face significant challenges.Methanol can be used as an intermediate carrier for hydrogen supplies,providing hydrogen energy through instant methanol conversion.In this study,a sorption-enhanced,chemical-looping,oxidative steam methanol-reforming(SECLOSRM)process is proposed using CuO–MgO for the on-board hydrogen supply,which could be a promising method for safe and efficient hydrogen production.Aspen Plus software was used for feasibility verification and parameter optimization of the SECL-OSRM process.The effects of CuO/CH_(3)OH,MgO/CH_(3)OH,and H_(2)O/CH_(3)OH mole ratios and of temperature on H_(2)production rate,H utilization efficiency,CH_(3)OH conversion,CO concentration,and system heat balance are discussed thoroughly.The results indicate that the system can be operated in autothermal conditions with high-purity hydrogen(99.50 vol%)and ultra-low-concentration CO(<50 ppm)generation,which confirms the possibility of integrating low-temperature proton-exchange membrane fuel cells(LT-PEFMCs)with the SECL-OSRM process.The simulation results indicate that the CO can be modulated in a lower concentration by reducing the temperature and by improving the H_(2)O/CH_(3)OH and MgO/CH_(3)OH mole ratios.展开更多
The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulf...The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11525211)the Natural Science Foundation of Anhui Province(Grant No.1908085QA32)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.WK2480000003)the Natural Science Foundation of Jiangsu Province(Grant No.BK20170457)
文摘Hydraulic fracturing has been widely applied in shale gas exploitation because it improves the permeability of the rock matrix.Fracturing stimulation parameters such as the pumping rate, the fracturing sequence, and the fracture spacing significantly influence the distribution of the stimulated reservoir volume(SRV). In this research, we built a numerical model that incorporates the hydraulic fracturing process and predicts gas production. The simulation of fracture propagation is based on the extended finite element method(XFEM), which helps to calculate aspects of the fractures and the SRV; we imported the results into a production analysis model as the initial conditions for production prediction. Using the model, we investigated the effects of some key parameters such as rock cohesion, fracture spacing, pumping rate, and fracturing sequence on the shale gas production.Our results proved that the SRV was distributed in the vicinity of the main fractures, and the SRVs were connected between the fractures in a small fracture spacing. We obtained optimal spacing by analyzing the production increment. High pumping-rate treatment greatly changes the in-situ stress around the hydraulic fractures and enlarges the field of SRV. Simultaneous fracturing treatment improves the flow conductivity of formation more than sequential fracturing. This study provides insights into the hydraulic fracturing design for economical production.
基金Financial support for this work was provided by the “14th Five-Year Plan” forward-looking basic major scientific and technological project of China National Petroleum Corporation’s (No. 2021DJ2303)the National Natural Science Foundation of China (Grant Nos. 42272195 and 42130802)Guizhou Provincial Science and Technology Program: Qiankehe Strategic Mineral Search (No. [2022] ZD001-01).
文摘The study of microbial communities in the produced water of coalbed methane(CBM)wells is an important aspect of microbial-enhanced methane production.Water produced from 15 CBM wells in four synclines in eastern Yunnan and western Guizhou was collected.Through the use of 16S ribosomal RNA(16S rRNA)amplicon sequencing and realtime fluorescence quantitative polymerase chain reaction(PCR),the characteristics of bacterial and archaeal communities before and after enrichment culture were studied.The methanogenic pathways of secondary biogas were discussed,and potential microbial-enhanced methane production was preliminarily evaluated.The results showed that the bacterial DNA content in uncultured produced water was low,so it is difficult to detect.After enrichment,the dominant bacteria phyla were Proteobacteria,Bacteroidetes,and Firmicutes.A total of seven phyla were detected in the uncultured produced water,and the dominant archaeal phylum was Euyarchaeota.Methanogens were the main component of archaea.The dominant archaeal genera were Methanobacterium,Methanoculleus and Methanobrevibacter.The community structure of the archaea changed noticeably after four days of enrichment culture.The relative abundance of Euryarchaeota increased to 99%in most samples after enrichment culture.It was found that there was a transition from Methanoregula to Methanobacterium within genera.The relative abundance of Methanobacterium increased,which can produce hydrogenotrophic methane.Combined with the isotopic composition of the produced water and gas,it is considered that the CBM in the Tucheng and Enhong synlines consists of a mixture of thermogenic gas and biogas.The proportion of secondary biogas in the Tucheng and Enhong synlines are estimated to range from 10.89% to 49.62%.There are mainly hydrogentrophic methanogens in the study area,and CO_(2) reduction is the main way of microbial gas production.After enrichment culture of produced water in the study area,the hydrogenotrophic methanogens were enriched.These two areas have stro
基金supported by National High Technology Research and Development Program of China (2006AA10A202)National Basic Research Program of China (2009CB118901)+2 种基金the National Natural Science Foundation of China (31820015)Ministry of Education of China (706021)the Science and Technology Commission of Shanghai Municipality (075407068)
文摘Oligomycins are a group of 26 macrocyclic lactones that exhibit broad biological activities,including antifungal,anticancer and nematocidal activities.Analysis of the oligomycin biosynthetic gene cluster (olm) in S.avermitilis revealed 2 tandem LuxR-type regulators,OlmRI (931 aa) and OlmRII (941 aa),with shared identity of 38%.Gene replacement of olmRI or olmRII abolished oligomycin production,and this production could be partially restored in the disruptants by introducing cloned olmRI and olmRII with their native promoters,demonstrating the essential role of OlmRI and OlmRII for oligomycin biosynthesis.Quantitative real-time RT-PCR analysis revealed that transcription of 14 olm genes was differentially affected by the deletion of olmRI and olmRII.Unexpectedly,avermectin production in both mutants was enhanced at least 4-fold.The identification of the positive cluster-situated regulators,OlmRI and OlmRII,paves the way for the transcriptional analysis of oligomycin biosynthesis and for the enhancement of oligomycin and avermectin production through regulator engineering.
文摘Conventionally oil recovery factor is too low,which leaves great prospects for the application of enhanced oil recovery(EOR)methods to increase recovery factor.EOR methods are capital intensive and few are environmentally hazardous.So the paper discusses on the alternate enhanced oil recovery technique which has tremendous potential to curb the challenges of conventional EOR methods.Plasma pulse technology(PPT)aided EOR treatment is administered with an electric wireline conveyed plasma pulse generator tool that is run in the well and positioned alongside the perforations.Using energy stored in the generator's capacitors,a plasma arc is created that emits a tremendous amount of heat and pressure for a fraction of a second.This in turn creates a broad band of hydraulic impulse acoustic waves that are powerful enough to clean perforations and near wellbore damage.These waves continue to resonate deep into the reservoir,exciting the fluid molecules and increasing the reservoirs natural resonance to the degree that it can break larger hydrocarbon molecules to smaller one and simultaneously reducing adhesion tension which results in increased mobility of hydrocarbons.The plasma pulse technology has been successfully used on production as well as injection wells.It has been used often as a remedial procedure to increase well's productivity that has been on production for a period of time.This paper throws light on fundamentals of this advancing plasma pulse technology,contrasting it with recent EOR techniques.Effectiveness of treatment in increasing oil recovery,it's applicability to different reservoir types and results achieved so far are also covered in the paper.
基金supported by the National Key R&D Program of China(2018YFE0111100)National Natural Science Foundation of China(52106193,21908162)+2 种基金the Natural Science Foundation of Hunan Province(2021JJ40756)the Science and Technology Innovation Program of Hunan Province(2020GK2070)the Innovation-Driven Project of Central South University(2020CX008)
文摘Hydrogen is an indispensable energy carrier for the sustainable development of human society.Nevertheless,its storage,transportation,and in situ generation still face significant challenges.Methanol can be used as an intermediate carrier for hydrogen supplies,providing hydrogen energy through instant methanol conversion.In this study,a sorption-enhanced,chemical-looping,oxidative steam methanol-reforming(SECLOSRM)process is proposed using CuO–MgO for the on-board hydrogen supply,which could be a promising method for safe and efficient hydrogen production.Aspen Plus software was used for feasibility verification and parameter optimization of the SECL-OSRM process.The effects of CuO/CH_(3)OH,MgO/CH_(3)OH,and H_(2)O/CH_(3)OH mole ratios and of temperature on H_(2)production rate,H utilization efficiency,CH_(3)OH conversion,CO concentration,and system heat balance are discussed thoroughly.The results indicate that the system can be operated in autothermal conditions with high-purity hydrogen(99.50 vol%)and ultra-low-concentration CO(<50 ppm)generation,which confirms the possibility of integrating low-temperature proton-exchange membrane fuel cells(LT-PEFMCs)with the SECL-OSRM process.The simulation results indicate that the CO can be modulated in a lower concentration by reducing the temperature and by improving the H_(2)O/CH_(3)OH and MgO/CH_(3)OH mole ratios.
基金supported by the National Science and Technology Council of Mexico(CONACYT)(No.192118)
文摘The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.
