波阻抗反演在南海北部神狐海域天然气水合物勘探中的应用

针对神狐海域的地质构造和天然气水合物的赋存特征,以重点测线三维地震数据为基础,分析讨论了基于宽带约束的模拟退火波阻抗反演方法、流程和关键技术问题,定量获得了含天然气水合物沉积物的波阻抗特征。结果表明:基于宽带约束的模拟退火波阻抗反演数据具有较高的有效垂向分辨率和较好的横向连续性;神狐海域高波阻抗异常反映了含天然气水合物沉积层,而不连续异常低波阻抗层是水合物层之下游离气的表现,这与钻探结果吻合。由此可见,基于宽带约束的模拟退火波阻抗反演可为天然气水合物层识别和预测、勘探目标圈定、钻探井位选择提供重要依据。     

鄂尔多斯盆地北部杭锦旗地区上古生界砂岩储层特征

以岩心及铸体薄片观察、扫描电镜鉴定、碳氧同位素测试、测井交会解释等为研究手段,系统研究了鄂尔多斯盆地北部杭锦旗上古生界储层特征.结果表明,研究区上古生界储层岩性复杂,存在岩屑长石砂岩、石英砂岩及岩屑砂岩等,北区东部见蒙脱石、高岭石及地开石等粘土矿物.储集空间以剩余原生粒间孔隙和次生孔隙组合为主,孔隙度中等,渗透率较低,排驱压力及饱和度中值压力较高,孔喉半径小且分选较差,孔隙结构总体较差,构造裂缝及微裂缝较发育,对油气运移成藏及储渗均有重要意义.根据储层岩性、物性及孔隙结构等参数特征,评价出4类储层.Ⅰ类储集岩是研究区最好的储集岩,Ⅱ、Ⅲ类储集岩是研究区主要储集岩,是勘探开发的主力储层.     

玲珑金矿田东山矿床矿体空间分带模型及应用

根据玲珑金矿田东山矿床地表及浅部勘查工程与采矿资料, 确定了成矿成晕元素种类。对成晕元素侧向分带特征和垂向分带规律的研究结果表明, 矿体上盘晕元素异常组合为Cu-As-Ag, 下盘晕元素异常组合为Cu-Te-As, 由此确定Au /As、Au /Pb、Au /Ag、Ag/Pb比值具有成矿判别意义, 即判别式Y₁ = 0.000 5 Au /As + 0.037 6 Au /Ag + 0.085 7 Au /Pb - 0.045 4 Ag/Pb > 0.009 2时指示含矿, 否则不含矿; 同时建立了基于Sb /As比值和Au、Ag、As、Sb 含量特征的见矿深度估计模型(H₁ = 1.104 9 + 79.63 k ( Sb /As) ×102 ) , 并对东山矿床主要矿体的可能成矿地段、见矿部位做出预测评价, 提出东山矿床9号、18号、47号、50号和52号支脉在175～ - 70 m标高范围内赋存金矿化或工业矿体。     

甘肃省舟曲8.7特大泥石流调查研究

本文通过对甘肃省舟曲县城后山三眼峪沟和罗家峪沟特大泥石流灾害的现场调查,从泥石流形成的地形、地质和降雨条件入手,分析了特大泥石流灾害的特征与成因:三眼峪沟和罗家峪沟泥石流形成区在2010年8月7日23～24时的1h降雨量达77.3mm,暴雨形成强大洪水依次冲毁两条沟内的天然堆石坝和人工拦挡坝,形成规模巨大的高容重黏性泥石流,泥石流冲出总量和泥沙总量分别为 144.2104m3和97.7104m3; 泥石流携带具有强大冲击力的巨石冲毁房屋5500余间; 在白龙江内形成长约550m,宽约70m,高约10m的堰塞坝并形成堰塞湖,堰塞湖回水长3km,使县城一半被淹; 泥石流造成1744人死亡和失踪。分析研究表明,三眼峪沟和罗家峪沟泥石流如果在近期遭遇强降雨还会暴发泥石流,但规模比87特大泥石流小;如果强降雨发生在数年后,暴发的泥石流规模比87特大泥石流略小;在20a或更长的时期内,没有发生新的地震影响下,在三眼峪沟和罗家峪沟经历一次大规模泥石流暴发后,泥石流的规模将回到汶川地震前的水平。     

堆载下单桩负摩阻力工作性状非线性数值分析

利用三维非线性数值方法对一算例在堆载作用下桩侧负摩阻力进行了计算分析。计算结果揭示了摩擦型、端承型桩负摩阻力工作性状的异同;分析了堆载速度、桩顶荷载对负摩阻力的影响:堆载越快,负摩阻力越小;在无桩顶荷载作用下,由负摩阻力引起的下拉荷载最大,可视为常规方法设计的上限值;桩顶荷载与堆载施工顺序对负摩阻力的影响也很大,先施加桩顶荷载,后进行堆载所产生的负摩阻力最大,反之最小。     

Estimation of aseismic crustal-strain using radon precursors of the 2003 <Emphasis Type="Italic">M</Emphasis> 6.8, 2006 <Emphasis Type="Italic">M</Emphasis> 6.1, and 2008 <Emphasis Type="Italic">M</Emphasis> 5.0 earthquakes in eastern Taiwan

Aseismic crustal-strain signals prior to the 2003 Mw 6.8 Chengkung, 2006 Mw 6.1 Taitung, and 2008 Mw 5.0 Antung earthquakes with epicenters located 20, 55 and 11 km, respectively, from the Antung radon-monitoring station have been calculated using the radon anomalies recorded. Specifically, radon decreased from background levels of 791 ± 46, 762 ± 57, and 735 ± 48 pCi/L to minima of 326 ± 9, 371 ± 9, and 480 ± 43 pCi/L prior to the 2003, 2006, and 2008 earthquakes, respectively. The estimated aseismic crustal-strain maxima at the Antung hot spring during the rock dilation stage were 3.6, 2.7, and 1.3 ppm, respectively. The v-shaped radon pattern recognized in all three anomalies is valuable for detecting the aseismic strain precursory to disastrous earthquakes in the Antung hot spring which is situated in a brittle fractured aquifer of limited recharge surrounded by ductile mudstone.     

地震纵波技术预测煤层瓦斯富集区的探讨与实践

基于国内外煤层瓦斯富集的岩石物理及地球物理响应的研究成果,提出了以煤层反射波振幅、频率及衰减等动力学特征变化为主要研究对象的地震纵波预测技术方案;探讨了利用叠后Gamma拟合声波约束反演、频谱分解属性分析和叠前AVO反演、弹性阻抗反演等纵波技术预测煤层瓦斯富集性的理论依据及实现方法。上述技术在沁水盆地进行了预测尝试,其获得的含气性预测成果与探井实测的瓦斯富集情况基本吻合,初步证明了上述纵波预测技术方法在开展煤层瓦斯富集区研究方面的可行性和有效性。     

Estimation of the methane flux from mud volcanoes along Chishan Fault,southwestern Taiwan

Because of the increasing public awareness of the greenhouse effect, geological emissions of methane (GEM) have gained more attention. The Intergovernmental Panel on Climate Change included GEM in the natural sources of methane category in the Fourth Assessment Report in 2007. The methane flux from mud volcanoes (MVs) is the second leading source within GEM. However, given that gas flux from MVs has been measured directly only in Sicily and Azerbaijan, the global methane estimation is still a conservative assumption based on limited data. The behavior of MV activities is seldom reported. This study attempts to estimate annual methane emissions through MVs by using a video recorder to record MV activities along the Chishan Fault and determining the bubble size and flux rate of each MV. Observation results, after a 1 year observation period, indicate that the annual emissions of the 19 MVs along the Chishan Fault are 0.1–0.2% of the global methane flux from MVs, highlighting that the methane emission from these MVs should not be neglected. In addition, the continuous monitoring of a particular MV disclosed periodic characteristics of MV activities. These results manifest the spatial and temporal variations of MV activities along the Chishan Fault. The spatial variations are related to the extensional kinematics of the Chishan fault, while the temporal variation relates to the earth-tide-related MV activities. The estimated annual methane emissions from the study are far more than those of previous studies and are still considered conservative. Results of this study may provide valuable information for researchers attempting to estimate the quantity of GEM.     

Monitoring severe aquifer-system compaction and land subsidence in Taiwan using multiple sensors: Yunlin,the southern Choushui River Alluvial Fan

During 1992–2007, excessive pumping of groundwater caused large-scale aquifer-system compaction and land subsidence in the Choshui River Alluvial Fan, especially in the area of Yunlin county. The subsidence impedes surface-water runoff and endangers the operation of Taiwan High Speed Rail. Leveling, Global Positioning System (GPS), multi-level compaction monitoring well, and Differential Interferometric Synthetic Aperture Radar (DInSAR) are used to study the extent of subsidence in Yunlin and its mechanism. These sensors complement each other in spatial and temporal resolutions. A leveling network totaling 434 km in length was deployed to derive subsidence at every 1.5 km along the routes, and the result is accurate to few mm and shows a basin-like subsidence pattern centering at Tuku Township. Four multi-level compaction monitoring wells, co-located with GPS pillars, detect compactions at different depths, showing that the aquifer-system compaction (the cause of subsidence) occurs mostly below depths >200 m, where reduction of groundwater pumping is most needed. The vertical displacements from GPS and leveling agree to within 1 cm, and are larger than the cumulative compaction detected by the compaction-monitoring wells, suggesting that compaction also occurs below 300 m (the depth of the wells). The vertical displacements derived using DInSAR and 8 ENVISAT SAR images agree with the leveling result to 1–2 cm.     

基于全基因组重测序技术的浙江近岸海域耐盐金黄色葡萄球菌(Staphylococcus aureus)耐药机制解析<

金黄色葡萄球菌(Staphylococcus aureus)是近岸海域海水中的主要病原菌,严重威胁接触者的安全。抗生素处理是治疗金黄色葡萄球菌感染的重要手段,其耐药性的发生受到了高度重视。采用全基因组重测序与KEGG富集分析结合的方法,对红霉素(erythromycin)、氯霉素(chloramphenicol)和万古霉素(vancomycin)处理后的耐盐金黄色葡萄球菌(S.aureus ZS01)和不耐盐金黄色葡萄球菌(S.aureus 502A)进行耐药机制研究。结果表明,S.aureus 502A经抗生素处理后发生突变的程度大于S.aureus ZS01,二者在经过氯霉素处理发生了更大程度的突变。红霉素、氯霉素和万古霉素处理主要影响了金黄色葡萄球菌的致病能力;红霉素和氯霉素可能通过影响金黄色葡萄球菌脂类的代谢引起其耐药性的变化。除此之外,三种抗生素处理均出现了较多TIGR01741家族蛋白和假设蛋白基因的突变,推测与菌株的耐药性和致病性相关。耐盐金黄色葡萄球菌可通过外排系统作用产生红霉素耐药性,不耐盐菌株因细胞壁成分相关基因的突变提高了对万古霉素的耐受性。研究结果可为耐盐和不耐盐金黄色葡萄球菌的耐药机制及抗生素对金黄色葡萄球菌致病性影响的研究提供基础数据。