Presence of carboxylate salts in marine carbonate strata of the Ordos Basin and their impact on hydrocarbon generation evaluation of low TOC, high maturity source rocks

The total organic carbon(TOC)in the marine source rock of the Ordos Basin mostly ranges from 0.2%to 0.5%.The industrial standard commonly states that the TOC value has to be no less than 0.5%(0.4%for high mature or over-mature source rock)to form large petroleum reservoirs.However,gas source correlation indicates that the natural gas in the Jingbian gas field does receive contribution from marine source rocks.In order to determine the effect of carboxylate salts(or called as organic acid salts)on TOC in highly mature source rocks with low TOC value,we sampled the Ordovician marine source rock and the Permian transitional facies source rock in one drilled well in the southern Ordos Basin and performed infrared and GC-MS analysis.It is found that both kerogen-derived organic acids and carboxylate salt-conversed organic acids exist in both marine and transitional facies source rocks.The carboxylate salt-conversed organic acids mainly come from the complete acidification of carboxylate salts,which confirms the presence of carboxylate salts in the marine source rocks.Although the C16:O peak is the main peak for the organic acids both before and after acidification,the carboxylate salt-conversed organic acids have much less relative abundance ahead of C16:O compared with that of the kerogen-based and free organic acids.This observation suggests that the kerogen-based and free organic acids mainly decarboxylate to form lower carboxylic acids,whereas the carboxylate salt-conversed organic acids mainly break down into paraffins.By using calcium hexadecanoate as the reference to quantify the kerogen-derived and carboxylate salt-conversed organic acids,the high TOC(>2.0%)marine source rocks have low carboxylate salt content and the low TOC(0.2%–0.5%)marine source rocks contain high content of carboxylate salt.Therefore,for the marine source rocks with 0.2%–0.5%TOC,the carboxylate salts may be a potential gas source at high maturity stage.     

GPS在地壳形变和板块运动监测中的应用

简要介绍了GPS在现代板块构造运动中的应用及其进展:GPS对于地球参考框架的建立和维持发挥着重要的作用;大量地壳运动监测网的建立使得GPS成为监测地壳运动强有力的工具;全球性、全天候的GPS卫星测高将在现代板块构造运动的监测中发挥重要作用;高精度的IGS产品为国际动力学服务提供坚实的数据基础。     

地球参考框架的建立和维持

详细总结了ITRF等参考框架的原理,分析了其优缺点和特性并分析了不同地球参考框架的区别。本文在协议研究的基础上,结合我国实际,提出了建立我国新一代地球参考系统的若干建议。     

裂隙充填型天然气水合物的各向异性分析及饱和度估算——以印度东海岸NGHP01-10D井为例

沿裂隙发育的天然气水合物是印度深水盆地细粒沉积物中水合物的重要产出方式,水合物以结核状或脉状充填在高角度裂隙中.天然气水合物主要沿着构造主应力方向生成,由于裂隙的存在,含水合物的沉积物层呈现各向异性.利用孔隙介质中水合物呈均匀分布的速度模型计算的NGHP01-10D井水合物饱和度高达40%,而压力取芯表明水合物饱和度占孔隙空间的20%左右.为了研究水合物饱和度差异,基于层状介质的各向异性模型计算了裂隙充填型水合物的饱和度.在垂直井孔中,由于波入射角与裂隙倾角有关,考虑裂隙倾角变化,利用纵波和横波速度同时反演水合物饱和度和裂隙倾角.利用层状介质模型计算的水合物占孔隙空间的15%～25%,裂隙的倾角在60°～90°,多为高角度裂隙.在NGHP01-10D井中,纵横波速度联合计算的饱和度与压力取芯结果吻合更好.     

超导重力仪检测2011年日本东北Mw9.0级地震前的重力扰动信号

对大地震前的扰动现象的研究有助于认识地震孕育的动力学过程,震前重力扰动已成为关注的热点之一. 对大地震前的扰动现象的研究有助于认识地震孕育的动力学过程,震前重力扰动已成为关注的热点之一. 为检验日本M_w9.0级地震是否存在震前扰动现象,本研究利用全球超导重力仪记录到的地震前后7天内20组秒采样数据进行分析. 经潮汐、大气改正等处理去除仪器的漂移及残余潮汐效应,得到非潮汐重力变化曲线.结果表明大部分振幅大于30×10^-8 m·s^-2的曲线反映了全球M_w≥6级地震引起的高频波动信号,其中11组数据在3月9日M_w7.3级前震之前出现了扰动现象.震前扰动可分解为三个频段,其中,低于0.1 Hz和高于0.18 Hz的分量分别反映了地震波动信号及非构造信息,中间频段(0.118~0.18 Hz)信号能够较大程度地压制地震波动信号、并同时保留异常扰动信息.它的振幅在3月7日10时之前基本保持约1×10^-8 m·s^-2,之后开始逐渐增大,到3月9日7.3级前震前后达到最大,此后振荡衰减,振幅保持约(5~10)×10^-8 m·s^-2,直至主震发生.中间频段信号的变化特征与主震前的应力迁移过程以及实验记录到的地震成核过程有许多相似之处;不过,震前重力异常是否与主震前的应力加速积累有关,仍待进一步研究.     

Late Quaternary (30.7–9.0 cal ka BP) vegetation history in Central Asia inferred from pollen records of Lake Balikun, northwest China

Surface and fossil pollen samples were collected to reconstruct the vegetation and environment since 30.7 cal ka BP in the Lake Balikun Basin, northwest China. This record demonstrates that the region was occupied by four vegetation communities during the interval 30.7–9.0 cal ka BP, including desert steppe (30.7–25.1 cal ka BP), Amaranthaceae-Asteraceae desert (25.1–17.7 cal ka BP), Amaranthaceae-Artemisia-Asteraceae desert (17.7–12.8 cal ka BP) and Amaranthaceae desert (12.8–9.0 cal ka BP), corresponding to relatively humid, the coldest and driest, cold and dry, and colder and drier conditions, respectively. The reconstructions of vegetation and environmental changes around Lake Balikun do not support the interpretation of an extremely humid LGM in Central Asia, challenging the cold-moist (glacial), warm-dry (interglacial) pattern of late Quaternary environmental change in Central Asia. The Last Glacial Maximum was cold and dry, and similarly harsh conditions continued into the early Holocene.     

全球六边形离散格网数据的三维可视化方法

针对全球六边形离散格网的三维显示化方法开展研究,设计了一种六边形格网的空间层次结构(hexagonalquaternary balanced structure,HQBS),采用四位码元对格网单元进行编码,定义并实现了格网向量的基本运算,利用这些运算可以方便地实现格网单元的空间索引。在此基础上还研究了全球离散格网的动态生成与显示算法、可视化区域裁剪等相关内容。试验表明:全球格网动态生成的效率110～370单元/ms之间,加载空间数据后,格网数据和空间数据逐层加载的时间在300 ms左右,能够保证加载空间数据后的显示刷新率在20帧/s左右。     

利用数值投影变换构建全球六边形离散格网

本文针对全球离散格网构建过程中从平面格网到球面格网的关键步骤进行讨论,提出了一种新型的评价球面离散格网几何属性最优化的目标函数,使用遗传算法优化,得到了球面上有限层次内最优化条件下的直接剖分格网。利用有限层次内最优化格网提供的控制点数据,结合数值投影变换理论,成功地构建了几何属性更加均匀的全球六边形离散格网系统。实验表明,相对于现有Snyder等积投影建立的全球格网,在格网单元的均匀度上更优;在运算效率方面,速度大约是Snyder投影的2.5-3倍。     

Integrated navigation system and experiment of a low-cost and low-accuracy SINS/GPS

When SINS (strap-down inertial navigation system) is combined with GPS, the observability of the course angle is weak. Although the course angle error is improved to some extent through Kalman filtering, the course angle still assumes a divergent trend. This trend is aggravated further when using low-cost and low-accuracy SINS. In order to restrain this trend, a method that uses AHRS to substitute for SINS course angle information is put forward aimed at the hardware component characteristic of the low-cost and low-accuracy SINS including AHRS (attitude and heading reference system) and IMU (inertial measurement unit). Real static and dynamic experiments show that the method can restrain the divergent trend of the navigation system angle effectively, and the positioning accuracy is high.     

Near real-time high-resolution airborne camera,AEROCam, for precision agriculture

Precision agriculture often relies on high-resolution imagery to delineate the variability within a field. Airborne Environmental Research Observational Camera (AEROCam) was designed to meet the needs of agriculture producers, ranchers, and researchers, who require high-resolution imagery in a near real-time environment for rapid decision support. AEROCam was developed and operated through a unique collaboration between several departments at the University of North Dakota, including the Upper Midwest Aerospace Consortium (UMAC), the School of Engineering and Mines, and flight operations at the John D. Odegard School of Aerospace Sciences. AEROCam consists of a Redlake MS4100 area-scan multi-spectral digital camera that features a 1920 × 1080 CCD array (7.4-μm detector) with 8-bit quantization. When operated at ～2 km above ground level, multispectral images with four bands in the visible and near infrared have a ground sample distance of 1 m with a horizontal extent of just over 1.6 km. Depending on the applications, flying at different altitudes can adjust the spatial resolution from 0.25 to 2 m. Rigorous spectral and radiometric calibrations allow AEROCam to be used in a variety of applications, qualitative and quantitative. Equipped with an inertial measurement unit (IMU) system, the images acquired can be geo-referenced automatically and delivered to end users near real time through our Digital Northern Great Plains system (DNGP). The images are also available to zone mapping application for precision farming (ZoneMAP), an online decision support tool for creating management zones from remote sensing imagery and data from other sources. Operational since 2004, AEROCam has flown over 250 sorties and delivered over 150,000 images to the users in the Northern Great Plains region, resulting in numerous applications in precision agriculture and resource management.