水平分支注浆孔卡埋钻事故处理实践

近年来煤矿奥灰治水注浆定向钻进技术发展迅速，多分支超深水平注浆孔数量激增。在水平注浆孔施工过程中，普遍存在地层漏失量大，泥浆突然失返，小径钻孔裸孔段长，水平段孔眼轨迹复杂，控制难度大，靶点技术误差要求严，定向仪器、工具等价格昂贵，施工风险相对较高，极易发生埋钻卡钻事故。一旦发生卡钻事故，就会面临着处理周期长、处理难度大等问题，传统的卡埋钻处理方法在水平注浆孔中应用效果不明显。通过采用空压机输送压缩空气，破坏水平孔着床的沉砂结构，将着床的沉砂吹出孔外或吹入地层裂隙，成功地实现了解卡。总结了水平注浆孔施工中卡埋钻事故的预防措施。     

Zircon U–Pb geochronology,whole-rock geochemical,and Sr–Nd–Pb isotopic constraints on the timing and origin of Permian and Triassic mafic dykes from eastern North China Craton

Acta Geochimica - This work reports an important episode of extensional, mafic magmatism that impacted the North China Craton (NCC) during the Permo-Triassic and influenced the evolution of this...     

Multi-stage metasomatism of lithospheric mantle by asthenosphere-derived melts: evidence from mantle xenoliths in daxizhuang at the eastern North China craton

Mineralogy and Petrology - A detailed study on petrology and mineral chemistry of 12 mantle xenoliths from Late Cretaceous basaltic lava flows at Daxizhuang has been conducted to constrain the...     

准噶尔盆地西北缘及玛湖凹陷沉积储集层研究进展*

准噶尔盆地西北缘玛湖凹陷中心区10×10⁸ t级砾岩大油区的发现,带动了该区沉积储集层研究的不断深入。作者梳理了准噶尔盆地西北缘及玛湖凹陷的沉积储集层研究现状和进展,认为准噶尔盆地西北缘及玛湖凹陷的沉积储集层研究的进展主要表现为: (1)提出了新的砂砾岩储集层岩石相和岩石学分析方法;(2)探索形成了新的沉积储集层地球物理测井和地震描述技术;(3)针对不同层系,在沉积物源、沉积相、沉积环境、沉积体系和沉积模式等方面取得大量新认识,建立了大型退覆式浅水缓坡扇三角洲沉积模式,指导油气勘探不断获得新突破;(4)在成岩作用理论指导下,所发现的储集层埋藏深度不断增加。研究表明,玛湖凹陷的沉积体系具有继承性: 从二叠纪到新近纪,发育了火山—碎屑岩沉积体系、细粒—蒸发盐沉积体系以及粗粒冲积扇、扇三角洲、辫状河三角洲等沉积体系,气候、构造和湖平面变化控制了沉积体系的形成和演化。沉积储集层研究为玛湖砾岩大油田的发现提供了有力的理论支持。未来应当加强针对古老层系和深部地层的沉积储集层研究工作,重视新理论新技术在西北缘和玛湖沉积储集层研究中的应用,已经形成的理论技术需要在勘探实践中接受进一步检验和完善。     

Implementation of a coupled plastic damage distinct lattice spring model for dynamic crack propagation in geomaterials

This paper studies dynamic crack propagation by employing the distinct lattice spring model (DLSM) and 3‐dimensional (3D) printing technique. A damage‐plasticity model was developed and implemented in a 2D DLSM. Applicability of the damage‐plasticity DLSM was verified against analytical elastic solutions and experimental results for crack propagation. As a physical analogy, dynamic fracturing tests were conducted on 3D printed specimens using the split Hopkinson pressure bar. The dynamic stress intensity factors were recorded, and crack paths were captured by a high‐speed camera. A parametric study was conducted to find the influences of the parameters on cracking behaviors, including initial and peak fracture toughness, crack speed, and crack patterns. Finally, selection of parameters for the damage‐plasticity model was determined through the comparison of numerical predictions and the experimentally observed cracking features.     

南极中山站全天信息采集系统

南极高原拥有独特的天文观测优势,为了对南极中山站夜天文观测条件进行实测研究,中国科学院云南天文台专门研制了一套具有耐低温、自动除雪除霜等适应南极气候特征的全自动全天信息采集系统,该系统可以提供实时的全天云量、天光背景和全天图像,并将信息推送到网页实时显示。介绍了系统的研制及为适应南极气候进行的耐低温实验,统计分析了中山站2016~2017年的全天信息数据,结果显示,中山站2016和2017年的可观测时间为772.21 h和437.38 h,可观测夜数为93 d和51 d,天光背景最大真实值为22.05 Mag/arcsec 2,年平均气温为-10.6℃,最高气温19.1℃,最低气温为-44℃,2016年平均相对湿度为55.2%。     

塔里木盆地苏盖特布拉克剖面寒武系第二统第三阶微生物岩结构类型*

塔里木盆地阿克苏地区寒武系第二统第三阶肖尔布拉克组主要由微生物白云岩组成,代表性的剖面在阿克苏市西南90 km处的苏盖特布拉克。由于成岩作用改造严重,对这套微生物碳酸盐岩的特征和形成环境的认识还存在很多分歧,制约了勘探工作。通过详细野外勘察和室内研究,将肖尔布拉克组微生物岩分为4种结构类型: 凝块结构、纹层结构、砂屑结构和骨架结构。首次对凝块结构和纹层结构进行了亚类型的划分,其中凝块结构可划分为蠕虫状、网状和斑点状3种亚类型,纹层结构可划分为致密纹层、短薄纹层、颗粒纹层以及单纹层、纹层组、复合纹层。肖Ⅰ段—肖Ⅲ段发育凝块石白云岩、凝块—层纹石白云岩和层纹石白云岩,肖Ⅳ段发育凝块石微生物丘,肖V段下部发育网状结构凝块石白云岩,肖V段上部发育砂屑白云岩和肾形菌骨架岩。白云石化作用、溶蚀作用、重结晶作用是改变肖尔布拉克组微生物岩结构最重要的成岩作用,且该组下部比上部遭受了更强的成岩作用改造;微生物岩结构对成岩作用改造的抵抗能力为: 砂屑结构>纹层结构>凝块结构。根据微生物岩结构,推测肖Ⅰ段—肖Ⅲ段形成于潮坪环境,肖Ⅳ段和肖V段下部形成于深水潮下环境,肖V段上部形成于浅水潮下环境。以上成果为认识塔里木盆地肖尔布拉克组微生物岩的平面分布规律和今后开展被成岩作用强烈改造的白云岩型微生物岩的研究提供了一个重要参考。     

Study of the flood control scheduling scheme for the Three Gorges Reservoir in a catastrophic flood

The Three Gorges Project is the world's largest water conservancy project. According to the design standards for the 1,000‐year flood, flood diversion areas in the Jingjiang reach of the Yangtze River must be utilized to ensure the safety of the Jingjiang area and the city of Wuhan. However, once these areas are used, the economic and life loss in these areas may be very great. Therefore, it is vital to reduce this loss by developing a scheme that reduces the use of the flood diversion areas through flood regulation by the Three Gorges Reservoir (TGR), under the premise of ensuring the safety of the Three Gorges Dam. For a 1,000‐year flood on the basis of a highly destructive flood in 1954, this paper evaluates scheduling schemes in which flood diversion areas are or are not used. The schemes are simulated based on 2.5‐m resolution reservoir topography and an optimized model of dynamic capacity flood regulation. The simulation results show the following. (a) In accord with the normal flood‐control regulation discharge, the maximum water level above the dam should be not more than 175 m, which ensures the safety of the dam and reservoir area. However, it is necessary to utilize the flood diversion areas within the Jingjiang area, and flood discharge can reach 2.81 billion m³. (b) In the case of relying on the TGR to impound floodwaters independently rather than using the flood diversion areas, the maximum water level above the dam reaches 177.35 m, which is less than the flood check level of 180.4 m to ensure the safety of the Three Gorges Dam. The average increase of the TGR water level in the Chongqing area is not more than 0.11 m, which indicates no significant effect on the upstream reservoir area. Comparing the various scheduling schemes, when the flood diversion areas are not used, it is believed that the TGR can execute safe flood control for a 1,000‐year flood, thereby greatly reducing flood damage.     

Regional Characteristics and Causes of Haze Events in Northeast China

Northeast China experiences severe atmospheric pollution, with an increasing occurrence of heavy haze episodes. However, the underlying forces driving haze formation during different seasons are poorly understood. In this study, we explored the spatio-temporal characteristics and causes of haze events in Northeast China by combining a range of data sources(i.e., ground monitoring, satellite-based products, and meteorological products). It was found that the ‘Shenyang-Changchun-Harbin(SCH)'city belt was the most polluted area in the region on an annual scale. The spatial distribution of air quality index(AQI) values had a clear seasonality, with the worst pollution occurring in winter, an approximately oval-shaped polluted area around western Jilin Province in spring, and the best air quality occurring in summer and most of the autumn. The three periods that typically experienced intense haze events were Period I from mid-October to mid-November(i.e., late autumn and early winter), Period II from late-December to February(i.e., the coldest time in winter), and Period III from April to mid-May(i.e., spring). During Period I, strong PM_(2.5) emissions from seasonal crop residue burning and coal burning for winter heating were the dominant reasons for the occurrence of extreme haze events(AQI 300). Period II had frequent heavy haze events(200 AQI 300) in the coldest months of January and February, which were due to high PM_(2.5) emissions from coal burning and vehicle fuel consumption, a lower atmospheric boundary layer, and stagnant atmospheric conditions. Haze events in Period III, with high PM_(10) concentrations, were primarily caused by the regional transportation of windblown dust from degraded grassland in central Inner Mongolia and bare soil in western Jilin Province. Local agricultural tilling could also release PM_(10) and enhance the levels of windblown dust from tilled soil. Better control of coal burning, fuel consumption, and crop residue burning in winter and autumn is urgently needed to address the haze problem in Northeast China.