国内振动钻机的发展及应用

振动钻进是指两个对称布置的等质量偏心体反向旋转产生离心力,水平分力抵消,竖向分力叠加,形成的激振力将物件沉人地层的一种钻进方法。依此原理制造的国内振动钻机经历了自20世纪80年代的机械传动式向21世纪初全液压驱动方式的转变,振动器结构型式经历了由低速单液压马达驱动一个偏心体、通过齿轮啮合传递到另一个偏心体的中低频振动器向高速双液压马达独立驱动两个偏心体的高频、超高频振动器的发展历程。举例重点介绍了近年来发展迅速的YSZ-50型钻机超高频振动钻机的取样应用情况,应用表明,该钻机钻进速度快、取样质量高,具有良好的市场发展前景和广阔的工程应用价值。     

Regional coal seam gas distribution and burial history of the Hunter Coalfield,Sydney Basin

Basin modelling has been used to improve understanding of the origin and temporal evolution of coal seam gas in the Hunter Coalfield of the Sydney Basin. Burial history models were produced based on data from seven boreholes located in the southern, eastern, central and western areas of the coalfield. Mean random vitrinite reflectance (R_v,r) data, derived from measurements of mean maximum reflectance (R_v,max), were used for calibration of the models. A qualitative sensitivity analysis of one model shows that varying the paleoheat flow has a greater influence on calculated R_v,r than varying the eroded overburden thickness.

The differences between the constructed models are significant enough to provide plausible explanations for regional gas distribution in the Hunter Coalfield. Coals in the south of the coalfield appear to have the greatest potential for thermogenic gas generation. Modelling has shown that areas that have low gas contents and decreased permeability have been uplifted more, and buried less, compared with areas that have high gas contents. Burial history modelling shows noticeable variations in the extent of burial and uplift, and, consequently, in thermal maturities and potential for thermogenic gas generation; together with the assessment of other coal and gas property data, it appears that present-day gas contents may partially reflect coal ranks and adsorption capacities, with late-stage biogenic gas generation replenishing CH₄ volumes that were lost following uplift during the Late Cretaceous.     

西昆仑阿什库勒火山群地质特征和活动分期

阿什库勒火山群作为青藏高原内最新期的北部昆仑火山群的典型代表,长期以来一直受到国内外地学界的广泛关注。我们通过对阿什库勒盆地火山区的野外地质地貌考察,研究了阿什库勒盆地内第四纪火山活动历史,完成了阿什库勒火山群重要火山锥体的1∶2000火山机构图。同时,对系统采集于不同火山机构和部位的20个火山岩样品进行了系列Ar-Ar同位素年代测试分析,获得了翔实的研究区不同火山岩石单元的绝对年龄数据。结合野外地质地貌考察结果,讨论了阿什库勒盆地的火山活动的第四纪时期活动历史,并将主要活动时期进一步划分为早更新世早期、早更新世中期、中更新世早期、中更新世晚期、晚更新世期和全新世期六期,取得了与前人有关该研究区火山活动历史和活动期次类似的划分方案,并补充了新的年代学证据。研究成果弥补了藏北高原西部由于恶劣工作环境而造成的第四纪火山学研究的不足。     

中国经济地理思想的历史演变及发展走向

中国经济地理思想史是一部经济活动与地理环境关系思想的进展史。古代时期产生了以适应和利用地理条件发展经济活动的思想;近代时期经济地理学作为学术领域出现;现代时期I重视自然条件的利用,从国家需求角度研究生产布局与地理条件的关系;现代时期II从国土整治与国土规划角度切入人地关系,构建“点—轴系统”理论等空间结构理论,根据区域差异扩大趋势提出调控思想;现代时期III结合主体功能区研究人地关系,注重产业集聚、都市经济区、农区衰退及振兴等问题。中国经济地理思想演化可以梳理出3支脉络：① 史志脉络通过历史文献对经济区位和地方差异的描述,逐步探究经济活动与地理条件的关系;海量的地方志,以实例支持人地关系思想。② 从游记考察到现代考察和观测分析,为经济地理研究提供了重要的科学事实发现手段。③ 国外引进脉络与多元思想本土化,带来不同的研究方法和思维逻辑。后两支脉络逐渐融入前一脉络,以突出中国特色之趋势。经济地理思想史研究可对当前经济地理学发展提供3点启迪：① 加强经济活动与地理环境关系的条件规律探索;② 鼓励问题导向的批判性思维;③ 弥补中国经济地理学研究的弱项,如与整体论对应的还原论,与归纳法对应的演绎法。     

Exhumation history and faulting activity of the southern segment of the Longmen Shan,eastern Tibet

The Longmen Shan (LMS), which constitutes the eastern border of the Tibetan Plateau, is about 400 km in length and characterized by a steep topographic transition from the Sichuan Basin to the plateau. The 2008 M_w7.9 Wenchuan earthquake and 2013 M_w6.6 Lushan earthquake were associated with the central to northern segments and southern segment of the LMS fault belt, respectively. In this paper, zircon and apatite fission track (ZFT and AFT, respectively) dating in combination with previously published low temperature thermochronology studies are used to constrain both the exhumation history and fault activity along the LMS, with a special focus on the southern segment. In the southern segment of the LMS, the ZFT ages in the hanging wall of the Wulong-Yanjing fault 10–14 Ma, increasing to ca. 30 Ma to the northwest of the faults and to 100–200 Ma in the plateau region. The AFT ages are 3–5 Ma at the mountain front and increase to 8–26 Ma in the plateau. We show that these age distributions are controlled by fault geometry. Two stages of rapid exhumation were identified using apatite fission track length modeling and the age distributions in the southern segment of the LMS. The first stage is from ca. 30 Ma and the second stage is from 3–5 Ma to present. In contrast with the middle segment of the LMS, the Cenozoic exhumation rate is higher in the southern segment of the LMS, which may be due to the influence of the collision between the India and Eurasia plates and/or different faulting mechanisms in the different segments.     

Tectono-thermal evolution of the Reed Bank Basin,Southern South China Sea

The Reed Bank Basin in the southern margin of the South China Sea is considered to be a Cenozoic rifted basin. Tectono-thermal history is widely thought to be important to understand tectonics as well as oil and gas potential of basin. In order to investigate the Cenozoic tectono-thermal history of the Reed Bank Basin, we carried out thermal modeling on one drill well and 22 pseudo-wells using the multi-stage finite stretching model. Two stages of rifting during the time periods of ∼65.5–40.4 Ma and ∼40.4–28.4 Ma can be recognized from the tectonic subsidence rates, and there are two phases of heating corresponding to the rifting. The reconstructed average basal paleo-heat flow values at the end of the rifting events are ∼60 and ∼66.3 mW/m², respectively. Following the heating periods, this basin has undergone a persistent thermal attenuation phase since ∼28.4 Ma and the basal heat flow cooled down to ∼57.8–63.5 mW/m² at present. In combination with the radiogenic heat production of the sedimentary sequences, the surface heat flow of the Reed Bank Basin ranges from ∼60.4 to ∼69.9 mW/m².     

埋藏历史对碳酸盐溶解-沉淀的影响——以四川盆地东北部三叠系飞仙关组和塔里木盆地北部奥陶系为例

埋藏成岩过程中碳酸盐的溶解与沉淀强烈控制着深埋藏地层中碳酸盐岩储层质量,与之有关的地质过程是人们多年来不懈研究的热点领域。热流体沿断裂向上运移所造成的碳酸盐溶解成为近年人们普遍认可的模式,但这不能圆满解释大量存在的不与断裂伴生的深埋藏碳酸盐的溶解机制。基于四川盆地东北部和塔里木盆地北部深埋藏碳酸盐溶解与沉淀机制的研究,认为埋藏过程中盆地的沉降与抬升是碳酸盐溶解与沉淀以及次生孔隙发育的另一重要机制,在改变流体对碳酸盐饱和状况方面具有和热流体沿断裂向上运移相同的重要性。研究表明:与川东北飞仙关组类似的埋藏历史更有利于深埋藏成岩过程中碳酸盐的溶解,主要特点是当前埋藏深度不是最大埋藏深度,在最大埋藏深度附近发生热化学硫酸盐还原作用,其后盆地持续抬升造成温度降低和碳酸盐溶解,与之有关的次生孔隙形成所造成的岩石力学性质的变化与上覆载荷减小可以得到平衡,次生孔隙得以保存,岩石储层质量改善;塔里木盆地北部的奥陶系埋藏历史不利于深埋藏成岩过程碳酸盐的溶解,主要特点是当前埋藏深度是最大埋藏深度,古喀斯特发生之后盆地持续沉降造成温度升高和碳酸盐沉淀,并与上覆载荷的增加同步发生,结果是孔隙的封堵、岩石的致密化和储层质量的变差。