Based on the oil,gas and water distribution characteristics of Khasib reservoir in Halfaya oilfield,Iraq,a core displacement experiment is designed to evaluate the influence of different displacement methods and displ...Based on the oil,gas and water distribution characteristics of Khasib reservoir in Halfaya oilfield,Iraq,a core displacement experiment is designed to evaluate the influence of different displacement methods and displacement parameters on oil displacement efficiency.The research shows that,in the displacement method with water injected from the edge of the reservoir,early depletion production is conducive to the elastic expansion of the gas cap,forming the three-dimensional displacement of"upper pressure and lower pushing",and the oil displacement effect is good.When gas injection at the top and water injection at the edge are used for synergistic displacement,the injection timing has different influences on the oil displacement effects of high and low parts.Considering the overall oil displacement efficiency,the injection pressure should be greater than the bubble point pressure of crude oil.Two displacement methods are recommended with the reasonable injection time at 20–25 MPa.The injection speed has the same influence on different injection media.Appropriately reducing the injection speed is conducive to the stability of the displacement front,delaying the breakthrough of injection media and improving the oil displacement effect.The reasonable injection rate of water flooding is 0.075 mL/min,the reasonable injection rates of water and gas are 0.15 mL/min and 0.10 mL/min,respectively in gas-water synergistic displacement.Gas-water synergistic displacement is conducive to the production of crude oil at high position,and has crude oil recovery 5.0%–14.8%higher than water flooding from the edge,so it is recommended as the development mode of Khasib reservoir at the middle and late stages.展开更多
Through analyzing 7 types of tourist resources in the Dawang Grotto Scenic Area(physiographic landscapes,waterscapes,biologic landscapes,historical remains,constructions and facilities,tourist products,human activitie...Through analyzing 7 types of tourist resources in the Dawang Grotto Scenic Area(physiographic landscapes,waterscapes,biologic landscapes,historical remains,constructions and facilities,tourist products,human activities),this study summarized the characteristics of this scenic area as "diversified physiographic landscapes,colorful rural life,beautiful waterscapes,picturesque mountain landscapes,rich biologic landscapes,and profound humanistic resources".On this basis,experience of other experts and research scientists were borrowed,classification system of ecotourism resources,AHP method,Delphi method and the comprehensive evaluation model of tourist site were applied,by classifying evaluation factors into 3 categories:resource value,ecological security and development condition,to categorize and divide the hierarchy of impact factors,determine the correlation among factors of different hierarchies and at different organization levels,and obtain weights of evaluation factors.Furthermore,development timing of ecotourism landscape resources in the Entrance Plaza Zone,Shengjing Lake Scenic Spot,Idyllic Scenic Spot,Shishen Youxian Scenic Spot,Dongfu Qiankun Scenic Spot was respectively evaluated.It was found that Dongfeng Qiankun Scenic Spot has better resources than others do,it has potentials to be developed into a first-class tourist site,but its ecological security and development condition should be further improved,and other four scenic spots need planning and development fit for their own characteristics.展开更多
Background:Onion grass(Romulea rosea)is a common weed that infests native and improved pastures in the Mediterranean environments of southern Australia.It is a very challenging weed to control due to its distinctive g...Background:Onion grass(Romulea rosea)is a common weed that infests native and improved pastures in the Mediterranean environments of southern Australia.It is a very challenging weed to control due to its distinctive growth and survival mechanisms involving corms.Methods:Three glasshouse experiments were conducted in Australia to investigate the response of onion grass to defoliation and fertiliser application,the development and growth of onion grass corms and the chemical control of the weed in winter and spring.Results:Defoliating consistently to 1 cm above ground reduced corm weight by 84%compared with the control.Medium or high fertiliser application did not increase herbage mass of onion grass compared with the nonfertilised treatment.The corm weight of onion grass declined from Weeks 1 to 8 after emergence,remained at 53-60 mg dry matter(DM)corm−1 from Weeks 8 to 19 and then declined on average to 37mgDMcorm−1 up to Week 26 after emergence.New corms started to develop at Week 6 after emergence.A small proportion of the onion grass plants(7.5%)developed multiple new corms(3-6 corms)from a single old corm.The most effective herbicide control was a winter application of metsulfuron methyl or imazamox as an alternative product to protect clover.Conclusions:This study has identified the growth and development patterns of onion grass corms,how the plant responded to defoliation and fertiliser application and effective chemical control of this weed.These findings have significant practical implications for the improvement of onion grass-infested pastures.展开更多
基金Supported by the Scientific Research and Technology Development Project of CNPC(2019D-4410)。
文摘Based on the oil,gas and water distribution characteristics of Khasib reservoir in Halfaya oilfield,Iraq,a core displacement experiment is designed to evaluate the influence of different displacement methods and displacement parameters on oil displacement efficiency.The research shows that,in the displacement method with water injected from the edge of the reservoir,early depletion production is conducive to the elastic expansion of the gas cap,forming the three-dimensional displacement of"upper pressure and lower pushing",and the oil displacement effect is good.When gas injection at the top and water injection at the edge are used for synergistic displacement,the injection timing has different influences on the oil displacement effects of high and low parts.Considering the overall oil displacement efficiency,the injection pressure should be greater than the bubble point pressure of crude oil.Two displacement methods are recommended with the reasonable injection time at 20–25 MPa.The injection speed has the same influence on different injection media.Appropriately reducing the injection speed is conducive to the stability of the displacement front,delaying the breakthrough of injection media and improving the oil displacement effect.The reasonable injection rate of water flooding is 0.075 mL/min,the reasonable injection rates of water and gas are 0.15 mL/min and 0.10 mL/min,respectively in gas-water synergistic displacement.Gas-water synergistic displacement is conducive to the production of crude oil at high position,and has crude oil recovery 5.0%–14.8%higher than water flooding from the edge,so it is recommended as the development mode of Khasib reservoir at the middle and late stages.
文摘Through analyzing 7 types of tourist resources in the Dawang Grotto Scenic Area(physiographic landscapes,waterscapes,biologic landscapes,historical remains,constructions and facilities,tourist products,human activities),this study summarized the characteristics of this scenic area as "diversified physiographic landscapes,colorful rural life,beautiful waterscapes,picturesque mountain landscapes,rich biologic landscapes,and profound humanistic resources".On this basis,experience of other experts and research scientists were borrowed,classification system of ecotourism resources,AHP method,Delphi method and the comprehensive evaluation model of tourist site were applied,by classifying evaluation factors into 3 categories:resource value,ecological security and development condition,to categorize and divide the hierarchy of impact factors,determine the correlation among factors of different hierarchies and at different organization levels,and obtain weights of evaluation factors.Furthermore,development timing of ecotourism landscape resources in the Entrance Plaza Zone,Shengjing Lake Scenic Spot,Idyllic Scenic Spot,Shishen Youxian Scenic Spot,Dongfu Qiankun Scenic Spot was respectively evaluated.It was found that Dongfeng Qiankun Scenic Spot has better resources than others do,it has potentials to be developed into a first-class tourist site,but its ecological security and development condition should be further improved,and other four scenic spots need planning and development fit for their own characteristics.
基金Department of Jobs,Precincts and Regions and the Glenelg-Hopkins Catchment Management,Victoria,Australia.
文摘Background:Onion grass(Romulea rosea)is a common weed that infests native and improved pastures in the Mediterranean environments of southern Australia.It is a very challenging weed to control due to its distinctive growth and survival mechanisms involving corms.Methods:Three glasshouse experiments were conducted in Australia to investigate the response of onion grass to defoliation and fertiliser application,the development and growth of onion grass corms and the chemical control of the weed in winter and spring.Results:Defoliating consistently to 1 cm above ground reduced corm weight by 84%compared with the control.Medium or high fertiliser application did not increase herbage mass of onion grass compared with the nonfertilised treatment.The corm weight of onion grass declined from Weeks 1 to 8 after emergence,remained at 53-60 mg dry matter(DM)corm−1 from Weeks 8 to 19 and then declined on average to 37mgDMcorm−1 up to Week 26 after emergence.New corms started to develop at Week 6 after emergence.A small proportion of the onion grass plants(7.5%)developed multiple new corms(3-6 corms)from a single old corm.The most effective herbicide control was a winter application of metsulfuron methyl or imazamox as an alternative product to protect clover.Conclusions:This study has identified the growth and development patterns of onion grass corms,how the plant responded to defoliation and fertiliser application and effective chemical control of this weed.These findings have significant practical implications for the improvement of onion grass-infested pastures.
