用云南下关测点的水压致裂结果分析地形起伏对应力测值的影响

本文以云南下关黄草坝的水压致裂应力测量结果为例,讨论了地形起伏对云南区应力测值的影响。结果表明,地形起伏对应力测值的绝对影响随深度的增加衰减缓慢,相对影响急剧减小。100米以内深度的应力测量,地形影响可能给测值带来10%以上的误差。云南区的水压致裂应力测量深达500米,是可以排除掉地形起伏的影响的。     

鄂西地区牛蹄塘组和陡山沱组优质页岩测井识别

以鄂西地区为例,利用钻井、测井及测试资料,开展牛蹄塘组和陡山沱组页岩岩相类型与地质属性（总有机碳含量、孔隙度、横向渗透率、脆性及孔隙类型）关系的研究.研究结果表明:鄂西地区共发育11类岩相页岩,不同岩相页岩间存在明显的地质属性差异.结合有机质页岩特征,识别出3种优质页岩类型:硅质页岩、富泥硅质页岩和混合质页岩.优质页岩含气量明显高于非优质页岩含气量,这证实了准确的优质页岩识别结果.通过对页岩测井影响因素的分析,总结出优质页岩具有高自然伽马、高电阻率、高声波时差、高铀、低密度、低钍、低钾（四高三低）的测井响应特征,从而提出适用于在鄂西高热演化区寻找具有低热演化程度,较强生烃潜力及易开发的页岩储层测井识别方法.      

Applicability of cosmic-ray neutron sensor for measuring soil moisture at the agricultural-pastoral ecotone in northwest China

Accurate monitoring of soil moisture is crucial in hydrological and ecological studies. Cosmic-ray neutron sensors (CRNS) measure area-average soil moisture at field scale, filling a spatial scale gap between in-situ observations and remote sensing measurements. However, its applicability has not been assessed in the agricultural-pastoral ecotone, a data scarce semi-arid and arid region in Northwest China (APENC). In this study, we calibrated and assessed the CRNS (the standard N₀ method) estimates of soil moisture. Results show that Pearson correlation coefficient, R_P, and the root mean square error (RMSE) between the CRNS soil moisture and the gravimetric soil moisture are 0.904 and less than 0.016 m³ m⁻³, respectively, indicating that the CRNS is able to estimate the area-average soil moisture well at our study site. Compared with the in-situ sensor network measurements (ECH2O sensors), the CRNS is more sensitive to the changes in moisture in its footprint, which overestimates and underestimates the soil moisture under precipitation and dry conditions, respectively. The three shape parameters a₀, a₁, a₂ in the standard calibration equation (N₀ method) are not well suited to the study area. The calibrated parameters improved the accuracy of the CRNS soil moisture estimates. Due to the lack of low gravimetric soil moisture data, performance of the calibrated N₀ function is still poor in the extremely dry conditions. Moreover, aboveground biomass including vegetation biomass, canopy interception and widely developed biological soil crusts adds to the uncertainty of the CRNS soil moisture estimates. Such biomass impacts need to be taken into consideration to further improve the accuracy of soil moisture estimation by the CRNS in the data scarce areas such as agricultural-pastoral ecotone in Northwest China.

     

下扬子皖南宣泾地区二叠系海相页岩特征及其沉积环境

为评价下扬子地区二叠系海相页岩层段页岩气勘探潜力,以皖南宣泾地区3口钻井岩心为例,通过岩心照片、薄片、X射线衍射、总有机碳等测试来分析页岩特征及其沉积环境.结果显示宣泾地区孤峰组中上部为富有机质层段,银屏组为贫有机质层段;宣泾东南地区大隆组中下部为高-富有机质层段,西北地区中上部为富有机质层段.孤峰组早期随着构造沉降和海水加深,宣泾地区形成了高生物生产力和缺氧环境,沉积了较厚硅质岩层;中晚期海平面缓慢下降,生物生存空间减少,高有机质沉降使水体硫化,TS含量增大,TOC含量达10%.银屏组沉积期海平面快速下降,变为浅海氧化环境,TOC含量小于1%.大隆组早期东南浅水斜坡位置受上升流影响,形成高生物生产力和缺氧环境,沉积了硅质岩层,TOC含量大于4%;中晚期海平面下降,TOC含量从东南浅水向西北深水变高.      

CLM4.5在西北农牧交错带盐池站的模拟性能评估

农牧交错带具有草地、裸地、农田大面积相互镶嵌的独特下垫面,其地表水热过程变化复杂,亟需深入研究。利用宁夏盐池站2017年实际观测资料,对陆面过程模式CLM4.5的模拟性能进行检验。结果表明,在复杂下垫面下,CLM4.5仍能较好地模拟出草地的地面反射辐射、地面长波辐射和净辐射以及0~10 cm土壤含水量和温度的变化特征,但模拟值与观测值还存在一定偏差。CLM4.5能模拟出辐射通量的日变化特征,除5月外,地面反射辐射模拟值与观测值之间的偏差较小。地面长波辐射模拟值白天偏高,净辐射观测值与模拟值的相关系数为0.99,均方根误差为22.50 W·m^-2。土壤含水量观测值与模拟值的相关系数达0.83,但模拟值偏低,且模式对降雨后土壤含水量变化过程的模拟性能有待提高。土壤温度模拟值的日变化特征较为明显,观测值与模拟值的相关系数为0.98,均方根误差为2.82℃。     

对混合土液塑限试验的讨论

土的液塑限试验是土工试验常见试验之一。含有一定数量粗粒组的混合土,用0.5 mm以下粒径范围的土作液塑限试验,得到的液塑限偏低,由此土的分类定名不符合实际。建议用0.075 mm以下粒径范围的土做液塑限试验。     

Lead in K－Feldspar and Its Relations to Rb Metallogenesis

In intermediate-acid magmatic rocks,alkaline magmatic rocks,gneisses and migmatitic rocks K-feldspar is a rock-forming rock in which the contents of Pb are highest,just 2-10 times those of the whole rock,3-16 times those of mica minerals and 6-32 times those of quartz.The lowest contents of K-feldspar are recognized in Early Proterozoic and Achaean rocks,with Pb in the K-feldspar accounting for less than 10% of that in the whole rock;in post Middle Proterozoic alkaine magmatic rocks,K-feldspar-rich granites and metamorphic rocks the contents of K-feldspar tend to increase,with the proportion granites and metamorphic rocks the contents of K-feldspar tend to increase,with the proportion of Pb over that in the whole rock being obviously increased.In the alkaline rocks in which K-feldspar accounts for 50%-70% of the total in the whole rock,the contents of Pb in K-feldspar account approximately for 70%-95% of the total lead in the whole rock.Being accessible to hydrothermal alteration in the late periods,K-feldspar was conversed to sericite,calcite,quartz,etc.In the process of such conversion the lead would be leached out and then find its way into fluid phase.This kind of trans-formation can provide sufficient ore-forming material for later Pb metallogenesis.