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81.
82.
陕北地区延长组发育低(特)渗储层,除发育通常的高阻油层外,还极易形成低阻油层;因此,低阻油层的发现,极大拓宽了该区石油勘探和开发的领域。根据志丹油田樊川油区长61的石油地质特征,结合大量实验和生产数据资料的分析对比,对该区低阻油层的成因机理及宏观控制因素进行了分析。结果表明:长61储层的孔隙结构复杂导致束缚水饱和度增高,高地层水矿化度、高泥质含量及放射性砂岩的存在,是低阻油层得以形成的主要原因。通过大量实际试油和测井资料的对比可见,应用计算自然电位与自然电位曲线重叠法可以快速直观显示其含油性,声波时差-深电阻率的交会图与自然伽马-深电阻率交会图相结合可有效识别低阻油层。对区内85口探井进行了测井资料的二次解释,在长6发现了初次解释所遗漏的45个低阻油层,油层数由原来的117个增加到162个,净增27.8%。 相似文献
83.
Paleoenvironments of the evolving Pliocene to early Pleistocene foreland basin in northwestern Taiwan: An example from the Dahan River section 下载免费PDF全文
The overriding of the Luzon volcanic arc atop the underlying Chinese rifted‐continental margin has caused the formation of the Taiwan mountain belts and a peripheral foreland basin west of the orogen since the late Miocene. In this study, lithofacies analysis and calcareous nannofossil biostratigraphic investigations of the Dahan River section in northwestern (NW) Taiwan were performed. Our results offer insights into the temporal evolution of the sedimentary environments and the competing effects of the sedimentation and basin tectonics of the NW Taiwan foreland basin from the Pliocene to early Pleistocene. Nannofossil biostratigraphic studies showed that the upper Kueichulin Formation and the overlying Chinshui Shale can be assigned to the NN15 biozone of the Pliocene age, and the Cholan Formation pertains to NN16–NN18 of the early Pleistocene. The NN15–NN16 boundary coincides roughly with the boundary of the Chinshui Shale and Cholan Formation. We recognized three major sedimentary environments in the studied foreland succession comprising the upper Kueichulin Formation, Chinshui Shale, Cholan Formation and Yangmei Formation, in ascending order. During the deposition of the upper Kueichulin Formation in the early Pliocene, the dominant environment was a wave‐ and tide‐influenced open marine setting. During the late Pliocene, the environment deepened to an outer‐offshore setting when the sediments of Chinshui Shale were accumulated. In the Pleistocene, the environment then shallowed to wave‐dominated estuaries during the deposition of the lower Cholan Formation, and the basin was rapidly filled, generating a meandering and sandy braided river environment during the deposition of the upper Cholan to the Yangmei Formation. In summary, the evolution of sedimentary environments in the studied succession shows a deepening then a shallowing and coarsening upward trend during the period from the Pliocene to the Pleistocene, spanning the age from approximately 4 to 1 Ma. 相似文献
84.
通过对前人研究的综述,发现青藏高原新生代地质演化与高原东南缘构造演化密切相关.俯冲下插的印度地壳在藏南发生部分熔融并注入青藏高原中部地壳,这些塑性流变的地壳物质在高原东南缘先后沿两个通道流出高原内部:早期为印支通道,开放时间为35 Ma以前并持续到12 Ma;后期为川滇通道,开放时间为12 Ma至今.由于喜马拉雅东构造结与四川盆地之间强烈的挤压,印支通道不断变窄,并在12 Ma被关闭.两个通道的差异,通道的打开和关闭,造成高原中地壳物质流出速率在中新世发生明显变化,在23 Ma以来流出速率小于注入速率,在12 Ma流出速率最小,部分熔融的印度地壳物质不断滞留于高原地壳内部,使得地势相对平坦、面积巨大的青藏高原逐渐形成并分别向南和向北扩展.通过简单的力学分析,本文将高原腹地变形划分为两个阶段:大于35~23 Ma的造山阶段,受控于造山机制;23 Ma至今的造高原阶段,受控于造高原机制. 相似文献
85.
天线相位中心偏差变化及改正模型对精密单点定位精度的影响 总被引:1,自引:0,他引:1
利用精密单点定位程序对IGS站的实测数据进行计算,结果表明:平面方向,天线相位中心偏差和变化对精密单点定位精度影响较小;高程方向,天线相位中心偏差可造成厘米级的影响,天线相位中心变化的影响约5 mm;相比相对天线相位中心改正模型,使用绝对相位改正模型具有更多优点,尤其用于高精度GPS授时其精度明显提高. 相似文献
86.
闽江河口咸草湿地冬季甲烷和二氧化碳通量及影响因子分析 总被引:2,自引:0,他引:2
闽江河口是我国东南沿海典型的开放式感潮河口,咸草Cyperus malaccensis var.brevifolius为闽江河口区最大的鳝鱼滩沼泽湿地的主要土著种。采用静态暗箱-气相色谱法,测定了2008年冬季(11月、12月和次年1月)咸草湿地涨潮前、涨落潮过程中和落潮后3个阶段排向大气环境的甲烷(CH4)和二氧化碳(CO2)通量特征。结果表明,涨落潮过程中咸草湿地排向大气环境的甲烷通量小于涨潮前和落潮后,在时间上表现为冬季3个月甲烷排放通量持续下降;咸草湿地二氧化碳通量同样表现为涨落潮过程中小于涨潮前和落潮后,在时间上也呈递减趋势;氧化还原电位(Eh)以及pH值对咸草湿地甲烷和二氧化碳排放通量具有不同程度的影响。 相似文献
87.
地动噪声功率谱及动态范围的一致性分析 总被引:1,自引:1,他引:0
在和田地震台阵中心子台安放9台CMG-40T型短周期地震计,采用EDAS-24IP数据采集器进行数据采集。对同一时段观测数据的地动噪声功率谱、动态范围等参数进行测定,并对测定结果进行对比,在使用者的角度分析该类型地震计的一致性。 相似文献
88.
Bin Zhang Wen Chen JingBo Sun Shun Yu JiYuan Yin Jie Li Yan Zhang XinYu Liu Li Yang Xia Yuan 《中国科学:地球科学(英文版)》2016,59(2):349-361
The uplift and exhumation process in the Tianshan orogen since the late Paleozoic were likely related to the preservation of ore deposits. This study involved reconstructing the whole tectonic thermal history of the Ouxidaban pluton in central South Tianshan Mountains based on hornblende/plagioclase Ar-Ar and zircon/apatite(U-Th)/He methods. The thermal history and uplift process of central South Tianshan Mountains since the late Paleozoic were analyzed according to the results of previous works and cooling/exhumation rate features. The hornblende yields a plateau age of 382.6±3.6 Ma, and the plagioclase yields a weighted mean age of 265.8±4.9 Ma. The Ouxidaban pluton yields weighted mean zircon(U-Th)/He age of 185.8±4.3 Ma and apatite(U-Th)/He age of 31.1±2.9 Ma, respectively. Five stages of tectonic thermal history of South Tianshan Mountains since the late Paleozoic could be discriminated by the cooling curve and modeling simulation:(1) from the latest Silurian to Late Devonian, the average cooling rate of the Ouxidaban pluton was 7.84°C/Ma;(2) from the Late Devonian to the latest Middle Permian, the average cooling rate was about 2.07°C/Ma;(3) from the latest Middle Permian to the middle Eocene, the cooling rate decreased to about 0.68°C/Ma, suggesting that the tectonic activity was gentle at this time;(4) a sudden increase of the cooling rate(5.00°C/Ma) and the exhumation rate(0.17 mm/a), and crustal exhumation of ~1.83 km indicated that the Ouxidaban pluton would suffer a rapid uplift event during the Eocene(~46?35 Ma);(5) since the middle Eocene, the rapid uplift was sustained, and the average cooling rate since then has been 1.14°C/Ma with an exhumation rate of about 0.04 mm/a and an exhumation thickness of 1.33 km. The strong uplift since the Cenozoic would be related to a far-field effect from the Indian and Eurasian plates' collision. However, it was hysteretic that the remote effect was observed in the Tianshan orogenic belt. 相似文献
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90.