Class III tight oil reservoirs have low porosity and permeability,which are often responsible for low production rates and limited recovery.Extensive repeated fracturing is a well-known technique to fix some of these ...Class III tight oil reservoirs have low porosity and permeability,which are often responsible for low production rates and limited recovery.Extensive repeated fracturing is a well-known technique to fix some of these issues.With such methods,existing fractures are refractured,and/or new fractures are created to facilitate communication with natural fractures.This study explored how different refracturing methods affect horizontal well fracture networks,with a special focus on morphology and related fluid flow changes.In particular,the study relied on the unconventional fracture model(UFM).The evolution of fracture morphology and flow field after the initial fracturing were analyzed accordingly.The simulation results indicated that increased formation energy and reduced reservoir stress differences can promote fracture expansion.It was shown that the length of the fracture network,the width of the fracture network,and the complexity of the fracture can be improved,the oil drainage area can be increased,the distance of oil and gas seepage can be reduced,and the production of a single well can be significantly increased.展开更多
The recovery factor from tight gas reservoirs is typically less than 15%, even with multistage hydrauhc tractunng stimulation. Such low recovery is exacerbated in tight gas condensate reservoirs, where the depletion o...The recovery factor from tight gas reservoirs is typically less than 15%, even with multistage hydrauhc tractunng stimulation. Such low recovery is exacerbated in tight gas condensate reservoirs, where the depletion of gas leaves the valuable condensate behind. In this paper, three enhanced gas recovery （EGR） methods including produced gas injection, CO2 injection and water injection are investigated to increase the well productivity for a tight gas condensate reservoir in the Montney Formation, Canada. The production performance of the three EGR methods is compared and their economic feasibility is evaluated. Sensitivity analysis of the key factors such as primary production duration, bottom-hole pressures, and fracture conductivity is conducted and their effects on the well production performance are analyzed. Results show that, compared with the simple depletion method, both the cumulative gas and condensate production increase with fluids injected. Produced gas injection leads to both a higher gas and condensate production compared with those of the CO2 injection, while waterflooding suffers from injection difficulty and the corresponding low sweep efficiency. Meanwhile, the injection cost is lower for the produced gas injection due to the on-site available gas source and minimal transport costs, gaining more economic benefits than the other EGR methods.展开更多
Vast amounts of world oil reservoirs are in natural fractured reservoirs. There are different methods for increasing recovery from fractured reservoirs. Miscible injection of water alternating CO2?is a good choice amo...Vast amounts of world oil reservoirs are in natural fractured reservoirs. There are different methods for increasing recovery from fractured reservoirs. Miscible injection of water alternating CO2?is a good choice among EOR methods. In this method, water and CO2?slugs are injected alternatively in reservoir as miscible agent into reservoir. This paper studies water injection scenario and miscible injection of water and CO2?in a two dimensional, inhomogeneous fractured reservoir. The results show that miscible water alternating CO2?gas injection leads to 3.95% increase in final oil recovery and total water production decrease of 3.89% comparing to water injection scenario.展开更多
Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution...Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution, however. The difference in burial depth of the reservoirs between east and west sides is up to 1000 m. Water-bearing formations exist between oil- and gas-bearing formations vertically and water-producing wells are drilled between oil- and gas-producing wells. Macroscopically, oil and gas occur at low positions, while water occurs at high positiona on the northern slope of Tazhong uplift. The mechanism of differential hydrocarbon enrichment in heterogeneous reservoirs is by far not clarified, which has affected the efficient exploration and development of oil and gas fields in this area.展开更多
The area,the scope as well as some ecological environment questions in Three Gorges Reservoir was briefly introduced. Then its early warning-system frame was preliminarily constructed,which includes ecological securit...The area,the scope as well as some ecological environment questions in Three Gorges Reservoir was briefly introduced. Then its early warning-system frame was preliminarily constructed,which includes ecological security dynamic monitoring,ecological security appraisal,ecological security forecast and ecological security decision-making management. The synthetic evaluation indicator system of the ecological security quality were initially established,which includes ecological environment pollution,land use and land cover change,geological hazard and epidemic outbreaks. At the same time,29 evaluating indicators were selected,divides into the basic factors,response factors and inducing factors,which need to be Real-time monitored.展开更多
Field SZ36-1 is a water-flooded heavy oil reservoir with high porosity and unconsolidated sand. The recovery rate is low so that it becomes a challenge for production. Time-lapse seismic data is studied to improve the...Field SZ36-1 is a water-flooded heavy oil reservoir with high porosity and unconsolidated sand. The recovery rate is low so that it becomes a challenge for production. Time-lapse seismic data is studied to improve the oil recovery for this field, This feasibility study analyzes the possible time-lapse seismic attribute spatial distribution using dynamic data and the reservoir model to determine the optimum time to acquire a new seismic survey. Based on the study, it is found that the time-lapse seismic response for this unconsolidated sand has a strong signature due to solution gas when the reservoir pressure is below the bubble point. This indicates that acquiring a new survey after 10 years of production is appropriate for a time-lapse seismic application.展开更多
This study aims the physico-chemical characterization of surface water of the Bir M＇Cherga reservoir and its effluents which are located in Zaghouan governorate of Tunisia. It required measures in situ of physicochem...This study aims the physico-chemical characterization of surface water of the Bir M＇Cherga reservoir and its effluents which are located in Zaghouan governorate of Tunisia. It required measures in situ of physicochemical parameters and chemical analysis at laboratory of major element and nutritive salts. The results of this study revealed the presence of pollutants in the Miliane river at El Fahs area and the eutrophication of water in the Bit M＇Cherga reservoir. According to the classification of Stuyfzand and Piper, water in the wadis of Melah, Hdada, Miliane and Boudebbane respectively is brackish, salty, extremely hard, chlorinated, sulphated, calcic, and magnesic. Water in the Bir M＇Cherga reservoir is characterized by calcic facies chlorinated sulphated and sodic. Thus, the Bir M＇Cherga reservoir presents a worrying situation and a risk of qualitative degradation of its water.展开更多
Population growth has consequences for intense use of aquatic ecosystems. Samples were taken, between 2013 and 2014, in the reservoirs ＂Algodoeiro＂ and ＂Gloria＂ in Sergipe, Brazil. TSI （Trophic State Index） and ...Population growth has consequences for intense use of aquatic ecosystems. Samples were taken, between 2013 and 2014, in the reservoirs ＂Algodoeiro＂ and ＂Gloria＂ in Sergipe, Brazil. TSI （Trophic State Index） and WQI （Water Quality Index） were used. It was determined the parameters such as conductivity, dissolved oxygen, total nitrogen, total phosphorus and chlorophyll. TSI has been applied, in ＂Algodoeiro＂, which was classified as mesotrophic. With the increase of rainfall in 2014, this reservoir changed its condition to eutrophic. ＂Gloria＂ reservoir was already classified in super-eutrophication. Regarding the WQI, the reservoirs were classified in Class IV, indicating a critically degraded condition.展开更多
基金the China Research and Pilot Test on Key Technology of Efficient Production of Changqing Tight Oil(Grant No.2021DJ2202).
文摘Class III tight oil reservoirs have low porosity and permeability,which are often responsible for low production rates and limited recovery.Extensive repeated fracturing is a well-known technique to fix some of these issues.With such methods,existing fractures are refractured,and/or new fractures are created to facilitate communication with natural fractures.This study explored how different refracturing methods affect horizontal well fracture networks,with a special focus on morphology and related fluid flow changes.In particular,the study relied on the unconventional fracture model(UFM).The evolution of fracture morphology and flow field after the initial fracturing were analyzed accordingly.The simulation results indicated that increased formation energy and reduced reservoir stress differences can promote fracture expansion.It was shown that the length of the fracture network,the width of the fracture network,and the complexity of the fracture can be improved,the oil drainage area can be increased,the distance of oil and gas seepage can be reduced,and the production of a single well can be significantly increased.
基金funding from Natural Sciences and Engineering Research Council of Canada (NSERC) for this researchsupport from the University of Calgary Beijing Research Site, a research initiative associated with the University of Calgary Global Research Initiative in Sustainable Low Carbon Unconventional Resources, the Kerui Group, and the Mitacs Accelerate program
文摘The recovery factor from tight gas reservoirs is typically less than 15%, even with multistage hydrauhc tractunng stimulation. Such low recovery is exacerbated in tight gas condensate reservoirs, where the depletion of gas leaves the valuable condensate behind. In this paper, three enhanced gas recovery （EGR） methods including produced gas injection, CO2 injection and water injection are investigated to increase the well productivity for a tight gas condensate reservoir in the Montney Formation, Canada. The production performance of the three EGR methods is compared and their economic feasibility is evaluated. Sensitivity analysis of the key factors such as primary production duration, bottom-hole pressures, and fracture conductivity is conducted and their effects on the well production performance are analyzed. Results show that, compared with the simple depletion method, both the cumulative gas and condensate production increase with fluids injected. Produced gas injection leads to both a higher gas and condensate production compared with those of the CO2 injection, while waterflooding suffers from injection difficulty and the corresponding low sweep efficiency. Meanwhile, the injection cost is lower for the produced gas injection due to the on-site available gas source and minimal transport costs, gaining more economic benefits than the other EGR methods.
文摘Vast amounts of world oil reservoirs are in natural fractured reservoirs. There are different methods for increasing recovery from fractured reservoirs. Miscible injection of water alternating CO2?is a good choice among EOR methods. In this method, water and CO2?slugs are injected alternatively in reservoir as miscible agent into reservoir. This paper studies water injection scenario and miscible injection of water and CO2?in a two dimensional, inhomogeneous fractured reservoir. The results show that miscible water alternating CO2?gas injection leads to 3.95% increase in final oil recovery and total water production decrease of 3.89% comparing to water injection scenario.
基金financially supported by the National Science Foundation of China(grant No.41372146)
文摘Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution, however. The difference in burial depth of the reservoirs between east and west sides is up to 1000 m. Water-bearing formations exist between oil- and gas-bearing formations vertically and water-producing wells are drilled between oil- and gas-producing wells. Macroscopically, oil and gas occur at low positions, while water occurs at high positiona on the northern slope of Tazhong uplift. The mechanism of differential hydrocarbon enrichment in heterogeneous reservoirs is by far not clarified, which has affected the efficient exploration and development of oil and gas fields in this area.
基金funded by National Natural Science Foundation Project (40801077)Ministry of Education Key Project (209100)+1 种基金Natural Science Foundation of Chongqing ( CSTC, 2008BB7367 )Chongqing Municipal Education Commission of Science and Technology Research Grant Project (KJ070811)~~
文摘The area,the scope as well as some ecological environment questions in Three Gorges Reservoir was briefly introduced. Then its early warning-system frame was preliminarily constructed,which includes ecological security dynamic monitoring,ecological security appraisal,ecological security forecast and ecological security decision-making management. The synthetic evaluation indicator system of the ecological security quality were initially established,which includes ecological environment pollution,land use and land cover change,geological hazard and epidemic outbreaks. At the same time,29 evaluating indicators were selected,divides into the basic factors,response factors and inducing factors,which need to be Real-time monitored.
文摘Field SZ36-1 is a water-flooded heavy oil reservoir with high porosity and unconsolidated sand. The recovery rate is low so that it becomes a challenge for production. Time-lapse seismic data is studied to improve the oil recovery for this field, This feasibility study analyzes the possible time-lapse seismic attribute spatial distribution using dynamic data and the reservoir model to determine the optimum time to acquire a new seismic survey. Based on the study, it is found that the time-lapse seismic response for this unconsolidated sand has a strong signature due to solution gas when the reservoir pressure is below the bubble point. This indicates that acquiring a new survey after 10 years of production is appropriate for a time-lapse seismic application.
文摘This study aims the physico-chemical characterization of surface water of the Bir M＇Cherga reservoir and its effluents which are located in Zaghouan governorate of Tunisia. It required measures in situ of physicochemical parameters and chemical analysis at laboratory of major element and nutritive salts. The results of this study revealed the presence of pollutants in the Miliane river at El Fahs area and the eutrophication of water in the Bit M＇Cherga reservoir. According to the classification of Stuyfzand and Piper, water in the wadis of Melah, Hdada, Miliane and Boudebbane respectively is brackish, salty, extremely hard, chlorinated, sulphated, calcic, and magnesic. Water in the Bir M＇Cherga reservoir is characterized by calcic facies chlorinated sulphated and sodic. Thus, the Bir M＇Cherga reservoir presents a worrying situation and a risk of qualitative degradation of its water.
文摘Population growth has consequences for intense use of aquatic ecosystems. Samples were taken, between 2013 and 2014, in the reservoirs ＂Algodoeiro＂ and ＂Gloria＂ in Sergipe, Brazil. TSI （Trophic State Index） and WQI （Water Quality Index） were used. It was determined the parameters such as conductivity, dissolved oxygen, total nitrogen, total phosphorus and chlorophyll. TSI has been applied, in ＂Algodoeiro＂, which was classified as mesotrophic. With the increase of rainfall in 2014, this reservoir changed its condition to eutrophic. ＂Gloria＂ reservoir was already classified in super-eutrophication. Regarding the WQI, the reservoirs were classified in Class IV, indicating a critically degraded condition.
