Affected by structural uplift, the Ordovician carbonate rockbed in the Tarim Basin, China, was exposed to dissolution and reformation of atmospheric precipitation many times, and formed a large quantity of karst caves...Affected by structural uplift, the Ordovician carbonate rockbed in the Tarim Basin, China, was exposed to dissolution and reformation of atmospheric precipitation many times, and formed a large quantity of karst caves serving as hydrocarbon reser- voir. However, drilling in Tahe area showed that many large karst caves, small pores and fractures are filled by calcite, result- ing in decrease in their reservoir ability. Calcite filled in the karst caves has very light oxygen isotopic composition and STSr/S（＇Sr ratio. Its c^OpDB ranges from -21.2%o to 13.3%o with the average of -16.3%e and its 87Sr/86Nr ratio ranges from 0.709561 to 0.710070 with the average of 0.709843. The isotope composition showed that calcite is related to atmospheric precipitation. Theoretic analyses indicated that the dissolving and filling actions of the precipitation on carbonate rocks are controlled by both thermodynamic and kinetic mechanisms. Among them, the thermodynamic factor determines that the pre- cipitation during its flow from the earth surface downward plays important roles on carbonate rocks from dissolution to satura- tion, further sedimentation, and finally filling. In other words, the depth of the karstification development is not unrestricted, but limited by the precipitation beneath the earth surface. On the other hand, the kinetic factor controls the intensity, depth, and breadth of the karstification development, that is, the karstification is also affected by topographic, geomorphologic, climatic factors, the degree of fracture or fault, etc. Therefore, subject to their joint effects, the karstification of the precipitation on the Ordovician carbonate rocks occurs only within a certain depth （most about 200 m） under the unconformity surface, deeper than which carbonate minerals begin to sedimentate and fill the karst caves that were formed previously.展开更多
Capillary filling in small length scale is an important process in nanotechnology and microfabrication. When one end of the tube or channel is sealed, it is important to consider the escape of the trapped gas. We deve...Capillary filling in small length scale is an important process in nanotechnology and microfabrication. When one end of the tube or channel is sealed, it is important to consider the escape of the trapped gas. We develop a dynamic model on capillary filling in closed-end tubes, based on the diffusion-convection equation and Henry＇s law of gas dissolution. We systematically investigate the filling dynamics for various sets of parameters, and compare the results with a previous model which assumes a linear density profile of dissolved gas and neglect the convective term.展开更多
950323 CT in predicting the efficacy of oralcholelitholysis with bile acids.FU Xianbo (傅贤波),et al.Dept Surg,3rd Teach Hosp,BeijingMed Univ,Beijing,100083.Natl Med J China1993;73(2):81—83.The efficacy of oral chole...950323 CT in predicting the efficacy of oralcholelitholysis with bile acids.FU Xianbo (傅贤波),et al.Dept Surg,3rd Teach Hosp,BeijingMed Univ,Beijing,100083.Natl Med J China1993;73(2):81—83.The efficacy of oral cholelitholytic therapywith chenodeoxycholic acid (CDCA) and ur-sodeoxycholic acid (UDCA) in 137 patients withgallstones was compared with their CT pat-terns.The best dissolving results were obtainedfrom patients with the stones in isodense andfaint category (【50Hu) on CT.All the stoneswith high density or heterogeneous calcificationon CT were insoluble.Therefore,they were con-traindicated for oral cholelitholytie therapy.Ac-cording to the abovr,criteria,the rates for disso-lution ranged from 27.7%(38/137).to 66.7%(38/57),and those for complete dissolutionranged from 9.49%(13/137) to 40.7%(11/展开更多
由于广泛而强烈的岩浆作用,我国东部的松辽、渤海湾、莺歌海以及西部的塔里木等盆地中都有富CO_2深部流体的活动。富CO_2深部流体与碳酸盐岩相互作用可用Duan and Li(2008)所建立的CO_2-H_2O-CaCO_3-NaCl体系的热力学模型来进行模拟计...由于广泛而强烈的岩浆作用,我国东部的松辽、渤海湾、莺歌海以及西部的塔里木等盆地中都有富CO_2深部流体的活动。富CO_2深部流体与碳酸盐岩相互作用可用Duan and Li(2008)所建立的CO_2-H_2O-CaCO_3-NaCl体系的热力学模型来进行模拟计算。计算结果表明,富CO_2深部流体在自深部向浅部运移过程中对CaCO_3的溶解度会逐渐增加,到达一定深度后溶解度达到最大值,再向浅部溶解度开始逐渐降低;也就是深部流体具有深部溶蚀碳酸盐岩—浅部沉淀碳酸盐矿物的规律。与浅部地层中的流体发生混合会使流体的CO_2含量和盐度降低,会导致CaCO_3的沉淀充填;深部流体进入开启性断裂/裂缝体系中时,由于压力的降低,也会发生CaCO_3的沉淀充填。深部流体的CO_2含量、盐度、温度和压力的变化影响着实际的溶蚀—充填过程。塔中地区钻井也揭示了深部下奥陶统碳酸盐岩中发育有丰富的溶蚀孔隙,而在相对浅部的奥陶系灰岩和志留系砂岩中见有大量方解石的充填,这是富CO_2流体深部溶蚀—浅部充填的一个较好的实例。基于理论和实际分析,本文认为在岩浆火山作用广泛发育的塔里木等盆地中下古生界深部优质碳酸盐岩储层存在的可能性。展开更多
基金sponsored by the National Basic Research Program of China(Grant No.2012CB214802)National Natural Science Foundation of China(Grant Nos.41002037,41102075,41230312)
文摘Affected by structural uplift, the Ordovician carbonate rockbed in the Tarim Basin, China, was exposed to dissolution and reformation of atmospheric precipitation many times, and formed a large quantity of karst caves serving as hydrocarbon reser- voir. However, drilling in Tahe area showed that many large karst caves, small pores and fractures are filled by calcite, result- ing in decrease in their reservoir ability. Calcite filled in the karst caves has very light oxygen isotopic composition and STSr/S（＇Sr ratio. Its c^OpDB ranges from -21.2%o to 13.3%o with the average of -16.3%e and its 87Sr/86Nr ratio ranges from 0.709561 to 0.710070 with the average of 0.709843. The isotope composition showed that calcite is related to atmospheric precipitation. Theoretic analyses indicated that the dissolving and filling actions of the precipitation on carbonate rocks are controlled by both thermodynamic and kinetic mechanisms. Among them, the thermodynamic factor determines that the pre- cipitation during its flow from the earth surface downward plays important roles on carbonate rocks from dissolution to satura- tion, further sedimentation, and finally filling. In other words, the depth of the karstification development is not unrestricted, but limited by the precipitation beneath the earth surface. On the other hand, the kinetic factor controls the intensity, depth, and breadth of the karstification development, that is, the karstification is also affected by topographic, geomorphologic, climatic factors, the degree of fracture or fault, etc. Therefore, subject to their joint effects, the karstification of the precipitation on the Ordovician carbonate rocks occurs only within a certain depth （most about 200 m） under the unconformity surface, deeper than which carbonate minerals begin to sedimentate and fill the karst caves that were formed previously.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21434001,21504004,and 21774004)
文摘Capillary filling in small length scale is an important process in nanotechnology and microfabrication. When one end of the tube or channel is sealed, it is important to consider the escape of the trapped gas. We develop a dynamic model on capillary filling in closed-end tubes, based on the diffusion-convection equation and Henry＇s law of gas dissolution. We systematically investigate the filling dynamics for various sets of parameters, and compare the results with a previous model which assumes a linear density profile of dissolved gas and neglect the convective term.
文摘950323 CT in predicting the efficacy of oralcholelitholysis with bile acids.FU Xianbo (傅贤波),et al.Dept Surg,3rd Teach Hosp,BeijingMed Univ,Beijing,100083.Natl Med J China1993;73(2):81—83.The efficacy of oral cholelitholytic therapywith chenodeoxycholic acid (CDCA) and ur-sodeoxycholic acid (UDCA) in 137 patients withgallstones was compared with their CT pat-terns.The best dissolving results were obtainedfrom patients with the stones in isodense andfaint category (【50Hu) on CT.All the stoneswith high density or heterogeneous calcificationon CT were insoluble.Therefore,they were con-traindicated for oral cholelitholytie therapy.Ac-cording to the abovr,criteria,the rates for disso-lution ranged from 27.7%(38/137).to 66.7%(38/57),and those for complete dissolutionranged from 9.49%(13/137) to 40.7%(11/
文摘由于广泛而强烈的岩浆作用,我国东部的松辽、渤海湾、莺歌海以及西部的塔里木等盆地中都有富CO_2深部流体的活动。富CO_2深部流体与碳酸盐岩相互作用可用Duan and Li(2008)所建立的CO_2-H_2O-CaCO_3-NaCl体系的热力学模型来进行模拟计算。计算结果表明,富CO_2深部流体在自深部向浅部运移过程中对CaCO_3的溶解度会逐渐增加,到达一定深度后溶解度达到最大值,再向浅部溶解度开始逐渐降低;也就是深部流体具有深部溶蚀碳酸盐岩—浅部沉淀碳酸盐矿物的规律。与浅部地层中的流体发生混合会使流体的CO_2含量和盐度降低,会导致CaCO_3的沉淀充填;深部流体进入开启性断裂/裂缝体系中时,由于压力的降低,也会发生CaCO_3的沉淀充填。深部流体的CO_2含量、盐度、温度和压力的变化影响着实际的溶蚀—充填过程。塔中地区钻井也揭示了深部下奥陶统碳酸盐岩中发育有丰富的溶蚀孔隙,而在相对浅部的奥陶系灰岩和志留系砂岩中见有大量方解石的充填,这是富CO_2流体深部溶蚀—浅部充填的一个较好的实例。基于理论和实际分析,本文认为在岩浆火山作用广泛发育的塔里木等盆地中下古生界深部优质碳酸盐岩储层存在的可能性。
