Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three di...Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three dimensional sedimentation structure in the bed of a recharge dam in Oman. A 3-D array of silt blocks sand- wiched by dry sand-filled horizontal and vertical fractures was studied in pot experiments as a model of a natural prototype. Pots are filled with a homogenous sand-silt mixture （control） or artificially structured （smart design, SD） soil substrates. Rhodes grass and ivy （Ipomea, Convolvulaceae） were grown in the pots during the hottest season in Oman. Soil moisture content （SMC） was measured at different depths over a period of 20 days without irrigation. SD preserved the SMC of the root zone for both ivy and grass （SMC of around 25%-30% compared to 〈10% for control, 3 days after the last irrigation）. Even after 20 days, SMC was around 18% in the SD and 7% in the control. This, similar to the case of a natural prototype, is attributed to the higher upward capillary movement of water in control pots and intensive evaporation. The capillary barrier of sand sheaths causes discontinuity in moisture mi- gration from the micro-pores in the silt blocks to sand pores. The blocks serve as capillarity-locked water buffers, which are depleted at a slow rate by transpiration rather than evaporation from the soil surface. This creates a unique ecosystem with a dramatic difference in vegetation between SD-pots and control pots. Consequently, the Noy-Meir edaphic factor, conceptualizing the ecological impact of 1-D vertical heterogeneity of desert soils, should be generalized to incorporate 3-D soil heterogeneity patterns. This agro-engineering control of the soil substrate and soil moisture distribution and dynamics （SMDaD） can be widely used by desert farmers as a cheap technique, with significant savings of irrigation water.展开更多
Establishing environmental institutions will aid in providing effective responses on any changes in the status of environment by improving the current policies by having solid management strategies to combat environme...Establishing environmental institutions will aid in providing effective responses on any changes in the status of environment by improving the current policies by having solid management strategies to combat environmental degradation. All the six member countries in the Gulf Cooperation Council (GCC) have established similar environmental institutional bodies that serve with the mandate of conserving and protecting the environment. Degrees of implementation, wealth, state of environment reporting and strategic planning are varying and closer inspection has to be done. Institutionalization in GCC states has to be promoted to cover major framework of sustainable development strategies. This will guarantee the use-effectiveness of those polices and other environmental management tools to ensure sustainable development of the natural resources. This paper attempts to list and examine the current status of all GCC country’s environment institutional framework and setup through comparison of the available information, highlighting the achievement of some and providing some guidance for others on how it could be enhanced.展开更多
Low salinity water is an emerging enhanced oil recovery(EOR)method that causes wettability alteration towards a favorable state to reduce residual oil saturation,while water alternating gas(WAG)is a proven EOR process...Low salinity water is an emerging enhanced oil recovery(EOR)method that causes wettability alteration towards a favorable state to reduce residual oil saturation,while water alternating gas(WAG)is a proven EOR process that enhances oil recovery by controlling mobility of both water and gas.Therefore,combining the two EOR processes as low salinity water-alternating CO2 EOR injection(LSWA CO2)can further improve oil recovery by promoting the synergy of the mechanisms underlying these two methods.Core flooding experiments,contact angle,interfacial tension(IFT),and CO2 solubility measurement in oil and brine were conducted to investigate the viability and performance of LSWA CO2 in sandstone reservoirs.A favorable wettability alteration,along with IFT reduction and mobility control,are the mechanisms that contribute to residual oil mobilization efficiencies during the LSWA CO2 EOR process.In addition,LSWA CO2 core flooding experiments result in a significant incremental oil recovery.Three smart waters were tested in our research,to examine the impact of changing cationic composition on oil recovery.The solutions are designed brines as NaCl(SW1),MgCl2(SW2),and KCl(SW3).Of the three solutions,SW1 yields the highest incremental oil recovery and highest IFT reduction.In addition,it results in a favorable wettability alteration towards a more water-wet state.In all cases,introducing CO2 to the brine/oil system shows a great advantage in terms of enhancing wettability modification,promoting IFT reduction,and controlling the displacement front of the injected fluid through mobility control.展开更多
基金support from the Grant IG/AGR/SWAE/10/02 of the Sultan Qaboos University
文摘Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three dimensional sedimentation structure in the bed of a recharge dam in Oman. A 3-D array of silt blocks sand- wiched by dry sand-filled horizontal and vertical fractures was studied in pot experiments as a model of a natural prototype. Pots are filled with a homogenous sand-silt mixture （control） or artificially structured （smart design, SD） soil substrates. Rhodes grass and ivy （Ipomea, Convolvulaceae） were grown in the pots during the hottest season in Oman. Soil moisture content （SMC） was measured at different depths over a period of 20 days without irrigation. SD preserved the SMC of the root zone for both ivy and grass （SMC of around 25%-30% compared to 〈10% for control, 3 days after the last irrigation）. Even after 20 days, SMC was around 18% in the SD and 7% in the control. This, similar to the case of a natural prototype, is attributed to the higher upward capillary movement of water in control pots and intensive evaporation. The capillary barrier of sand sheaths causes discontinuity in moisture mi- gration from the micro-pores in the silt blocks to sand pores. The blocks serve as capillarity-locked water buffers, which are depleted at a slow rate by transpiration rather than evaporation from the soil surface. This creates a unique ecosystem with a dramatic difference in vegetation between SD-pots and control pots. Consequently, the Noy-Meir edaphic factor, conceptualizing the ecological impact of 1-D vertical heterogeneity of desert soils, should be generalized to incorporate 3-D soil heterogeneity patterns. This agro-engineering control of the soil substrate and soil moisture distribution and dynamics （SMDaD） can be widely used by desert farmers as a cheap technique, with significant savings of irrigation water.
文摘Establishing environmental institutions will aid in providing effective responses on any changes in the status of environment by improving the current policies by having solid management strategies to combat environmental degradation. All the six member countries in the Gulf Cooperation Council (GCC) have established similar environmental institutional bodies that serve with the mandate of conserving and protecting the environment. Degrees of implementation, wealth, state of environment reporting and strategic planning are varying and closer inspection has to be done. Institutionalization in GCC states has to be promoted to cover major framework of sustainable development strategies. This will guarantee the use-effectiveness of those polices and other environmental management tools to ensure sustainable development of the natural resources. This paper attempts to list and examine the current status of all GCC country’s environment institutional framework and setup through comparison of the available information, highlighting the achievement of some and providing some guidance for others on how it could be enhanced.
文摘Low salinity water is an emerging enhanced oil recovery(EOR)method that causes wettability alteration towards a favorable state to reduce residual oil saturation,while water alternating gas(WAG)is a proven EOR process that enhances oil recovery by controlling mobility of both water and gas.Therefore,combining the two EOR processes as low salinity water-alternating CO2 EOR injection(LSWA CO2)can further improve oil recovery by promoting the synergy of the mechanisms underlying these two methods.Core flooding experiments,contact angle,interfacial tension(IFT),and CO2 solubility measurement in oil and brine were conducted to investigate the viability and performance of LSWA CO2 in sandstone reservoirs.A favorable wettability alteration,along with IFT reduction and mobility control,are the mechanisms that contribute to residual oil mobilization efficiencies during the LSWA CO2 EOR process.In addition,LSWA CO2 core flooding experiments result in a significant incremental oil recovery.Three smart waters were tested in our research,to examine the impact of changing cationic composition on oil recovery.The solutions are designed brines as NaCl(SW1),MgCl2(SW2),and KCl(SW3).Of the three solutions,SW1 yields the highest incremental oil recovery and highest IFT reduction.In addition,it results in a favorable wettability alteration towards a more water-wet state.In all cases,introducing CO2 to the brine/oil system shows a great advantage in terms of enhancing wettability modification,promoting IFT reduction,and controlling the displacement front of the injected fluid through mobility control.
