The sandstones of the paleogene in the Huimin Depression have undergone numerous diagenetic processes, such as compaction, cementation, dissolution, metasomasis and recrystallization. The first three — compaction, ...The sandstones of the paleogene in the Huimin Depression have undergone numerous diagenetic processes, such as compaction, cementation, dissolution, metasomasis and recrystallization. The first three — compaction, cementation and dissolution — affect reservoir properties most intensively. An average porosity loss due to compaction is 0.78% per 100 meters, slightly higher in the central and southern parts and lower in the northern. Cementation has resulted in the porosity loss from 8% to 20% at a depth below 1,500 meters. Dissolution, which in most cases is the dissolution of feldspar and of carbonate cement, primarily occurs in two depth intervals, from 1,400 to 2,500 meters and 2,700 to 4,000 meters respectively. New porosity is created through dissolution from 4% to 14%. The sandstones experienced stage A and stage B of early diagenesis and stage A of late diagenesis. At present, most of them are experiencing Phase A2 of late diagenesis. The types of pores in the sand reservoir can be grouped into primary and secondary ones.展开更多
Engineering experience shows that outward dipping bedded rock slopes, especially including weak interlayers, are prone to slide under rainfall conditions. To investigate the effect of inclined weak interlayers at vari...Engineering experience shows that outward dipping bedded rock slopes, especially including weak interlayers, are prone to slide under rainfall conditions. To investigate the effect of inclined weak interlayers at various levels of depth below the surface on the variation of displacements and stresses in bedded rock slopes, four geo- mechanical model tests with artificial rainfall have been conducted. Displacements, water content as well as earth pressure in the model were monitored by means of various FBG （Fiber Bragg Grating） sensors. The results showed that the amount of displacement of a slope with a weak interlayer is 2.8 to 6.2 times larger than that of a slope without a weak interlayer during one rainfall event. Furthermore, the position of the weak interlayer in terms of depth below the surface has a significant effect on the zone of deformation in the model. In the slope with a high position weak interlayer, the recorded deformation was larger in the superficial layer of the model and smaller in the frontal portion than in the slope with a low position weak interlayer. The slope with two weak interlayers has the largest deformation at all locations of all test slopes. The slope without a weak interlayer was only saturated in its superficial layer, while the displacement decreased with depth. That was different from all slopes with a weak interlayer in which the largest displacement shifted from the superficial layer to the weak interlayer when rainfall persisted. Plastic deformation of the weak interlayer promoted the formation of cracks which caused more water to flow into the slope, thus causing larger deformation in the slope with weak interlayers. In addition, the slide thrust pressure showed a vibration phenomenon o.5 to 1 hour ahead of an abrupt increase of the deformation, which was interpreted as a predictor for rainfall-induced failure of bedded rock slopes.展开更多
The intra-formational seal capability was characterized by multi-layered shale baffles to act as the primary or ultimate cap system, were taken into account by homogeneous and heterogeneous models, respectively. In th...The intra-formational seal capability was characterized by multi-layered shale baffles to act as the primary or ultimate cap system, were taken into account by homogeneous and heterogeneous models, respectively. In this study, the relevant ranges of input parameter of porosity （20%-35%） and permeability （0.0001-1,000 mD）, respectively for the sandstone （storage layers） and shale （seals） have been selected, according to results of large amount of laboratory core, test from pilot 3,000 m drilling within Tai-Hsi Foreland Basin in Western Taiwan. By a comprehensive geological model, typical single well injected plume migration scenarios were stochastically simulated which covered a 20-year continuous injection （one Mt-CO2 per year） followed by a 1,000-year post-injection monitoring. The corresponding 2-D MHMD （maximum horizontal migration distances） of CO2 plume in the storage reservoir had been calculated with respect to heterogeneous reservoir models and their homogeneous counterparts. Moreover, the induced pressures at critical monitoring points above the injection zone were also evaluated. As a result, the shale baffles of intra-formational seal in a saline aquifers are proven to play a vital role, and capable of ensuring the safe carbon storage operation within a basin scale with a depth range about 2,100-2,500 mRT.展开更多
Diyarbaklr basalt aquifer is volcanic-rock aquifers which contain high quality water. It was main resources for Diyarbaklr city center drinking supply up to 2005. Somewhere, basalt aquifer groundwater is still used fo...Diyarbaklr basalt aquifer is volcanic-rock aquifers which contain high quality water. It was main resources for Diyarbaklr city center drinking supply up to 2005. Somewhere, basalt aquifer groundwater is still used for irrigation in rural areas of Diyarbaklr city. In the study, Diyarbaklr city center＇s （which is located on the Tigris river basin） basalt aquifer groundwater potentials and hydrogeological features are examined and modeled by using GIS programmer. Firstly, general geological data, meteorological data and general information about natural water sources are collected together, afterwards, logs of well drilled by public institutions and private individuals within the Diyarbaklr city center are analyzed. Static water level, dynamic water level and well pumps yields are classified in these logs. Then, thematic maps produced with the help of Arc Info Professional GIS programmer with geostatistical analyst tool. Groundwater source potential of Diyarbaktr is examined by means of these thematic maps. In hydrogeological research, productivity by aquifer features, water retention capacity and groundwater level data evaluated with geological structure of area are taken into consideration.展开更多
Through the analysis of the occurring and developing process of the rockburst under the high strata stress, it points out that the action of stress wave is the key factor to affect the rockburst process. The character...Through the analysis of the occurring and developing process of the rockburst under the high strata stress, it points out that the action of stress wave is the key factor to affect the rockburst process. The characteristics of stress wave as well as its relation with the strata stress and the mechanism of its causing rockburst are explained. Finally, the preventing measures of the rockburst caused by the stress wave are put forward.展开更多
文摘The sandstones of the paleogene in the Huimin Depression have undergone numerous diagenetic processes, such as compaction, cementation, dissolution, metasomasis and recrystallization. The first three — compaction, cementation and dissolution — affect reservoir properties most intensively. An average porosity loss due to compaction is 0.78% per 100 meters, slightly higher in the central and southern parts and lower in the northern. Cementation has resulted in the porosity loss from 8% to 20% at a depth below 1,500 meters. Dissolution, which in most cases is the dissolution of feldspar and of carbonate cement, primarily occurs in two depth intervals, from 1,400 to 2,500 meters and 2,700 to 4,000 meters respectively. New porosity is created through dissolution from 4% to 14%. The sandstones experienced stage A and stage B of early diagenesis and stage A of late diagenesis. At present, most of them are experiencing Phase A2 of late diagenesis. The types of pores in the sand reservoir can be grouped into primary and secondary ones.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41502299,41372306)Research Planning of Sichuan Education Department,China(Grant No.16ZB0105)
文摘Engineering experience shows that outward dipping bedded rock slopes, especially including weak interlayers, are prone to slide under rainfall conditions. To investigate the effect of inclined weak interlayers at various levels of depth below the surface on the variation of displacements and stresses in bedded rock slopes, four geo- mechanical model tests with artificial rainfall have been conducted. Displacements, water content as well as earth pressure in the model were monitored by means of various FBG （Fiber Bragg Grating） sensors. The results showed that the amount of displacement of a slope with a weak interlayer is 2.8 to 6.2 times larger than that of a slope without a weak interlayer during one rainfall event. Furthermore, the position of the weak interlayer in terms of depth below the surface has a significant effect on the zone of deformation in the model. In the slope with a high position weak interlayer, the recorded deformation was larger in the superficial layer of the model and smaller in the frontal portion than in the slope with a low position weak interlayer. The slope with two weak interlayers has the largest deformation at all locations of all test slopes. The slope without a weak interlayer was only saturated in its superficial layer, while the displacement decreased with depth. That was different from all slopes with a weak interlayer in which the largest displacement shifted from the superficial layer to the weak interlayer when rainfall persisted. Plastic deformation of the weak interlayer promoted the formation of cracks which caused more water to flow into the slope, thus causing larger deformation in the slope with weak interlayers. In addition, the slide thrust pressure showed a vibration phenomenon o.5 to 1 hour ahead of an abrupt increase of the deformation, which was interpreted as a predictor for rainfall-induced failure of bedded rock slopes.
文摘The intra-formational seal capability was characterized by multi-layered shale baffles to act as the primary or ultimate cap system, were taken into account by homogeneous and heterogeneous models, respectively. In this study, the relevant ranges of input parameter of porosity （20%-35%） and permeability （0.0001-1,000 mD）, respectively for the sandstone （storage layers） and shale （seals） have been selected, according to results of large amount of laboratory core, test from pilot 3,000 m drilling within Tai-Hsi Foreland Basin in Western Taiwan. By a comprehensive geological model, typical single well injected plume migration scenarios were stochastically simulated which covered a 20-year continuous injection （one Mt-CO2 per year） followed by a 1,000-year post-injection monitoring. The corresponding 2-D MHMD （maximum horizontal migration distances） of CO2 plume in the storage reservoir had been calculated with respect to heterogeneous reservoir models and their homogeneous counterparts. Moreover, the induced pressures at critical monitoring points above the injection zone were also evaluated. As a result, the shale baffles of intra-formational seal in a saline aquifers are proven to play a vital role, and capable of ensuring the safe carbon storage operation within a basin scale with a depth range about 2,100-2,500 mRT.
文摘Diyarbaklr basalt aquifer is volcanic-rock aquifers which contain high quality water. It was main resources for Diyarbaklr city center drinking supply up to 2005. Somewhere, basalt aquifer groundwater is still used for irrigation in rural areas of Diyarbaklr city. In the study, Diyarbaklr city center＇s （which is located on the Tigris river basin） basalt aquifer groundwater potentials and hydrogeological features are examined and modeled by using GIS programmer. Firstly, general geological data, meteorological data and general information about natural water sources are collected together, afterwards, logs of well drilled by public institutions and private individuals within the Diyarbaklr city center are analyzed. Static water level, dynamic water level and well pumps yields are classified in these logs. Then, thematic maps produced with the help of Arc Info Professional GIS programmer with geostatistical analyst tool. Groundwater source potential of Diyarbaktr is examined by means of these thematic maps. In hydrogeological research, productivity by aquifer features, water retention capacity and groundwater level data evaluated with geological structure of area are taken into consideration.
文摘Through the analysis of the occurring and developing process of the rockburst under the high strata stress, it points out that the action of stress wave is the key factor to affect the rockburst process. The characteristics of stress wave as well as its relation with the strata stress and the mechanism of its causing rockburst are explained. Finally, the preventing measures of the rockburst caused by the stress wave are put forward.
