Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction ...Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction of deep hot dry rock(HDR) reservoirs and proposes suggestions for the research focus of numerical simulation of HDR reservoir stimulation. Additionally, it summarizes the existing methods and mainstream working fluids for HDR reservoir stimulation. The article emphasizes the significance of factors such as well location, production well depth, artificial fracture orientation, and complexity in optimizing the thermal production efficiency of the EGS. Furthermore, this article delves into a detailed discussion on the influence of fracture spacing, fracture permeability,fracture length, fluid injection rate, and injected fluid temperature on the performance of the EGS. In light of the thermo-hydro-mechanical coupling challenges associated with high-temperature reservoirs, it is suggested that future research efforts should focus on investigating the impact of thermo-induced stresses on the stability of the artificial fracture network within the EGS during long-term(>30 years) circulation of hot and cold fluids.展开更多
In this paper, the reservoir temperatures of 14 hot spring samples collected from the northern segment of theRed River Fault are calculated by using the mixing-model of SiO2-geothermometer. Based on the features ofres...In this paper, the reservoir temperatures of 14 hot spring samples collected from the northern segment of theRed River Fault are calculated by using the mixing-model of SiO2-geothermometer. Based on the features ofreservoir temperatures and densities of hot springs, the northern segment of the Red River Fault is furtherdivided into 4 sub-segments. The influence of weakening effect of water on seismic activities is discussed fromthe view point of fault-weakening effect of water. It is suggested that the difference in seismic activity between various sub-segments is principally caused by the difference in intensity of the fault-weakening effect ofwater of these sub-segments. The Eryuan sub-segment where the reservoir temperatures are high and the hotsprings are dense corresponds to a slipped region, however, the Jianchuan and Midu sub-segments where thereservoir temperatures are lower and the hot springs are fewer as well as the Dan sub-segment where the hotspring are very few all correspond to locked regions. It is suggested that Dan sub-segment is the riskiest region for strong earthquake preparation, while the possibility for strong earthquake preparation is very little inthe Eryuan sub-segment.展开更多
Organic-inorganic interactions between hydrocarbons and most minerals in deeply buried reservoirs remain unclear.In this study,gold capsules and fused silica capillary capsules(FSCCs)with different com-binations of nC...Organic-inorganic interactions between hydrocarbons and most minerals in deeply buried reservoirs remain unclear.In this study,gold capsules and fused silica capillary capsules(FSCCs)with different com-binations of nC_(16)H_(34),water(distilled water,CaCl_(2) water)and minerals(quartz,feldspar,calcite,kaolinite,smectite,and illite)were heated at 340℃ for 3-10 d,to investigate the evolution and reaction pathways of the organic-inorganic interactions in different hot systems.After heating,minerals exhibited little alteration in the anhydrous systems.Mineral alterations,how-ever,occurred obviously in the hydrous systems.Different inorganic components affected nC_(16)H_(34) degra-dation differently.Overall,water promoted the free-radical thermal-cracking reaction and step oxidation reaction but suppressed the free-radical cross-linking reaction.The impact of CaCl_(2) water on the nC_(16)H_(34) degradation was weaker than the distilled water as high Ca^(2+)concentration suppressed the formation of free radicals.The presence of different waters also affects the impact of different minerals on nC_(16)H_(34) degradation,via its impact on mineral alterations.In the anhydrous nC_(16)H_(34)-mineral systems,calcite and clays catalyzed generation of low-molecular-weight(LMW)alkanes,particularly the clays.Quartz,feldspar,and calcite catalyzed generation of high-molecular-weight(HMW)alkanes and PAHs,whereas clays catalyzed the generation of LMW alkanes and mono-bicyclic aromatic hydrocarbons(M-BAHs).In the hydrous nC_(16)H_(34)-distilled water-mineral systems,all minerals but quartz promoted nC_(16)H_(34) degra-dation to generate more LMW alkanes,less HMW alkanes and PAHs.In the nC_(16)H_(34)-CaCl_(2) water-mineral systems,the promotion impact of minerals was weaker than that in the systems with distilled water.This study demonstrated the generation of different hydrocarbons with different fluorescence colors in the different nC_(16)H_(34)-water-mineral systems after heating for the same time,implying that fluorescence colors need to be interpreted carefully in investigation of hydrocarbon charging histories and oil origins in deeply buried reservoirs.Besides,the organic-inorganic interactions in different nC_(16)H_(34)-water-mineral systems proceeded in different pathways at different rates,which likely led to preservation of liquid hydrocarbons at different depth(temperature).Thus,quantitative investigations of the reaction kinetics in different hydrocarbon-water-rock systems are required to improve the prediction of hydrocar-bon evolution in deeply buried hydrocarbon reservoirs.展开更多
水力压裂技术是实现低渗油气及地热储层的高效开发利用的关键技术手段,为了研究干热岩型地热储层水力压裂过程中水力裂缝的扩展规律,本文使用粘结单元法(Cohesive Zone Method,CZM)研究了压裂液排量、压裂液粘度以及水平地应力差对水力...水力压裂技术是实现低渗油气及地热储层的高效开发利用的关键技术手段,为了研究干热岩型地热储层水力压裂过程中水力裂缝的扩展规律,本文使用粘结单元法(Cohesive Zone Method,CZM)研究了压裂液排量、压裂液粘度以及水平地应力差对水力裂缝形态的影响,并利用正交试验对上述压裂工艺参数的组合进行优化。结果表明:压裂液排量对水力裂缝的长度具有重要影响,而压裂液的粘度对水力裂缝的宽度具有显著影响;压裂液的排量和粘度的增加,促进了分支裂缝的萌生和扩展;水平地应力差为1 MPa时,本文所建立的模型在压裂液排量和粘度分别取0.004 m3/s和0.07 Pa·s条件下,可获得最佳的压裂改造效果;随着压裂液的排量和粘度的持续增加,当压裂液的排量和粘度分别超过0.004 m3/s和0.07 Pa·s后,继续增加压裂液的排量和粘度将导致水力裂缝的长度和宽度的减小,可见在实际压裂过程中不能盲目通过提高压裂液的排量和粘度的方式实现对压裂效果的持续改进。本文丰富了干热岩储层改造的数值模拟手段,相关研究成果有望为干热岩型地热资源开采过程中裂缝扩展行为预测和压裂工艺参数的优化提供技术支撑。展开更多
基金Research Foundation of the Department of Natural Resources of Hunan ProvinceGrant/Award Number:20230101DZ+7 种基金Natural Science Foundation of Hunan ProvinceGrant/Award Number:2023JJ20062National Key Research and Development Program of ChinaGrant/Award Number:2022YFC2903704National Natural Science Foundation of ChinaGrant/Award Number:52104112Science and Technology Innovation Program of Hunan Province of ChinaGrant/Award Number:2023RC3051。
文摘Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction of deep hot dry rock(HDR) reservoirs and proposes suggestions for the research focus of numerical simulation of HDR reservoir stimulation. Additionally, it summarizes the existing methods and mainstream working fluids for HDR reservoir stimulation. The article emphasizes the significance of factors such as well location, production well depth, artificial fracture orientation, and complexity in optimizing the thermal production efficiency of the EGS. Furthermore, this article delves into a detailed discussion on the influence of fracture spacing, fracture permeability,fracture length, fluid injection rate, and injected fluid temperature on the performance of the EGS. In light of the thermo-hydro-mechanical coupling challenges associated with high-temperature reservoirs, it is suggested that future research efforts should focus on investigating the impact of thermo-induced stresses on the stability of the artificial fracture network within the EGS during long-term(>30 years) circulation of hot and cold fluids.
文摘In this paper, the reservoir temperatures of 14 hot spring samples collected from the northern segment of theRed River Fault are calculated by using the mixing-model of SiO2-geothermometer. Based on the features ofreservoir temperatures and densities of hot springs, the northern segment of the Red River Fault is furtherdivided into 4 sub-segments. The influence of weakening effect of water on seismic activities is discussed fromthe view point of fault-weakening effect of water. It is suggested that the difference in seismic activity between various sub-segments is principally caused by the difference in intensity of the fault-weakening effect ofwater of these sub-segments. The Eryuan sub-segment where the reservoir temperatures are high and the hotsprings are dense corresponds to a slipped region, however, the Jianchuan and Midu sub-segments where thereservoir temperatures are lower and the hot springs are fewer as well as the Dan sub-segment where the hotspring are very few all correspond to locked regions. It is suggested that Dan sub-segment is the riskiest region for strong earthquake preparation, while the possibility for strong earthquake preparation is very little inthe Eryuan sub-segment.
基金funded by the Natural Science Foundation of China Project(Grant Nos.41821002,41872140)the Special fund for Taishan Scholar Project(Grant No.tsqn201909061)the Fundamental Research Funds for the Central Universities(Grant No.20CX06067A)。
文摘Organic-inorganic interactions between hydrocarbons and most minerals in deeply buried reservoirs remain unclear.In this study,gold capsules and fused silica capillary capsules(FSCCs)with different com-binations of nC_(16)H_(34),water(distilled water,CaCl_(2) water)and minerals(quartz,feldspar,calcite,kaolinite,smectite,and illite)were heated at 340℃ for 3-10 d,to investigate the evolution and reaction pathways of the organic-inorganic interactions in different hot systems.After heating,minerals exhibited little alteration in the anhydrous systems.Mineral alterations,how-ever,occurred obviously in the hydrous systems.Different inorganic components affected nC_(16)H_(34) degra-dation differently.Overall,water promoted the free-radical thermal-cracking reaction and step oxidation reaction but suppressed the free-radical cross-linking reaction.The impact of CaCl_(2) water on the nC_(16)H_(34) degradation was weaker than the distilled water as high Ca^(2+)concentration suppressed the formation of free radicals.The presence of different waters also affects the impact of different minerals on nC_(16)H_(34) degradation,via its impact on mineral alterations.In the anhydrous nC_(16)H_(34)-mineral systems,calcite and clays catalyzed generation of low-molecular-weight(LMW)alkanes,particularly the clays.Quartz,feldspar,and calcite catalyzed generation of high-molecular-weight(HMW)alkanes and PAHs,whereas clays catalyzed the generation of LMW alkanes and mono-bicyclic aromatic hydrocarbons(M-BAHs).In the hydrous nC_(16)H_(34)-distilled water-mineral systems,all minerals but quartz promoted nC_(16)H_(34) degra-dation to generate more LMW alkanes,less HMW alkanes and PAHs.In the nC_(16)H_(34)-CaCl_(2) water-mineral systems,the promotion impact of minerals was weaker than that in the systems with distilled water.This study demonstrated the generation of different hydrocarbons with different fluorescence colors in the different nC_(16)H_(34)-water-mineral systems after heating for the same time,implying that fluorescence colors need to be interpreted carefully in investigation of hydrocarbon charging histories and oil origins in deeply buried reservoirs.Besides,the organic-inorganic interactions in different nC_(16)H_(34)-water-mineral systems proceeded in different pathways at different rates,which likely led to preservation of liquid hydrocarbons at different depth(temperature).Thus,quantitative investigations of the reaction kinetics in different hydrocarbon-water-rock systems are required to improve the prediction of hydrocar-bon evolution in deeply buried hydrocarbon reservoirs.
