鄂尔多斯盆地环西—彭阳地区长8段储层流体性质测井判别方法

鄂尔多斯盆地环西—彭阳地区长8段储层蕴含丰富油气资源，但储层非均质性强，孔隙结构复杂，且受异常低压、黏土矿物附加导电以及高束缚水饱和度影响，油水层分异差，测井响应特征差异不明显，流体性质识别难度大。本文通过岩芯薄片观察、常规测井等资料，对长8段储层四性关系等进行了研究，结果表明长8段岩性主要是中、细砂岩，平均孔隙度14. 68%，渗透率7. 13×10-3 μm2。在此基础上引入视地层水电阻率作为有效参数，建立RwaAC交会图版，该方法考虑了不同储层物性的差异对储层电性的影响，克服了储层孔隙结构复杂因素的影响，突出了含油气信息，能有效识别不同的流体类型，通过该方法实现了12口井70个层位流体性质测井判别，与试油资料验证良好。研究成果对于长8段储层测井评价和油气勘探开发具有指导意见。     

CryoSat-2测高数据与Landsat 8光学数据融合提取南极Amery冰架接地线

本文利用CryoSat-2测高数据与Landsat 8光学数据,针对南极Amery冰架区域开展接地线提取研究.首先通过Landsat 8光学影像三次Hermite多项式插值处理,在坡度分析的基础上利用表面曲率改进方法获取接地线特征点;同时对CryoSat-2测高数据进行坡度分析和表面曲率计算,通过沿轨梯度分析方法提取接地点;最后将Landsat 8与CryoSat-2数据获取的接地点进行最小二乘融合得到融合接地线.实验结果表明,融合结果利用高空间分辨率光学数据不仅能保证接地线提取精度,同时测高数据还能够弥补光学数据受云遮挡导致的数据空缺,保持接地线的完整性.与MOA产品比较可以看出,融合数据点与MOA接地线平均距离为367 m,标准差为601 m,所有数据点中距离小于1 km的点占总数的93.19%,与MOA产品具有较好一致.本文提出的融合算法可以实现空间连续的接地线提取结果,对后续研究南极物质平衡、冰流速计算等具有重要的意义.     

Period analysis of theδ Scuti star HD93044

HD93044 was observed electrophotometricaly on April 21, May 1, 2 and 4, 1991 at Xinglong Station of Beijing Astronomical Observatory. Combining the data with Li Zhiping's data together and a period analysis was completed using a program which consists of a combination of Fourier transforms of prewhitened data and the multifrequency least squares of brightness residuals (LSR). Three pulsation frequencies (11.90809, 16.79553, 22.44827 cycles per day) with visual amplitudes between 0.0056 and 0.0203 mag were found. The solution fits the observations to +0.0071 mag which is equal to the mean square deviation of observations. The first frequency (11.90809 cycles per day) must be the right value of the fundamental frequency of HD93044.     

Impact ejecta and carbonate sequence in the eastern sector of the Chicxulub crater

The Chicxulub 200 km diameter crater located in the Yucatan platform of the Gulf of Mexico formed 65 Myr ago and has since been covered by Tertiary post-impact carbonates. The sediment cover and absence of significant volcanic and tectonic activity in the carbonate platform have protected the crater from erosion and deformation, making Chicxulub the only large multi-ring crater in which ejecta is well preserved. Ejecta deposits have been studied by drilling/coring in the southern crater sector and at outcrops in Belize, Quintana Roo and Campeche; little information is available from other sectors. Here, we report on the drilling/coring of a section of 34 m of carbonate breccias at 250 m depth in the Valladolid area (120 km away from crater center), which are interpreted as Chicxulub proximal ejecta deposits. The Valladolid breccias correlate with the carbonate breccias cored in the Peto and Tekax boreholes to the south and at similar radial distance. This constitutes the first report of breccias in the eastern sector close to the crater rim. Thickness of the Valladolid breccias is less than that at the other sites, which may indicate erosion of the ejecta deposits before reestablishment of carbonate deposition. The region east of the crater rim appears different from regions to the south and west, characterized by high density and scattered distribution of sinkholes.     

Late Glacial-Holocene sequence of Lake Saint-Point (Jura Mountains, France): Detrital inputs as records of climate change and anthropic impact

A sediment sequence (SP05, 12.5 m long) was taken from the deep zone of Lake Saint-Point (850 m a.s.l.). Sedimentological analyses highlight two main contrasted periods of sedimentation: the Last Glacial Maximum (LGM)/Late Glacial characterized by high silicates and quartz contents the Holocene dominated by the carbonated fraction. At the beginning of the Holocene (11 400 years cal. BP), silicates fraction flux abruptly decreased. The shift between the Late Glacial and the Holocene periods may be explained by forest development in the catchment. From 10 200 to 6800 years cal. BP, silicates and detrital carbonate fractions remained stable before they progressively increased steady till 5000 years cal. BP. Both increases cannot be totally attributed to an anthropic impact since pollen data indicate continuous anthropic activities only dated back from 3000 years cal. BP. They thus resulted from a dominant climatic control. From 5000 years cal. BP, silicates content still increased while detrital carbonates input became steady due to a change in pedogenetic processes affecting the catchment. During the last millennium, silicates and detrital carbonate decreased, probably due to pastureland development.     

Holocene hydrological and vegetation changes in southern France inferred by the study of an alluvial travertine system (Saint-Guilhem-le-Désert, Hérault)

A geobotanical study of the travertine system of Saint-Guilhem-le-Désert (southern France) was carried out in order to reconstruct the local Holocene environment in a region where the postglacial vegetation history is poorly documented. The travertinisation process has started at ca. 8500 cal. BP, in a landscape dominated by Pinus sylvestris type (probably Pinus nigra sub sp. salzmannii). Around 7000 cal. BP, the travertine system recorded torrential events not evidenced at the regional scale, showing the particularity of the Verdus hydrological regime. More recently, ca. 5100 cal. BP, a lake or a marsh was filled within the Verdus plain, as attested to by sand and silt particles accumulated in the sequence. The present-day vegetation dominated by Quercus ilex, on south facing slopes, was most likely established between the Bronze Age and the Gallo-Roman period correlatively to the decline of Pinus nigra and deciduous Quercus, most probably under human influence.     

鄂尔多斯盆地苏里格中部水平井开发区盒8段沉积微相和砂体展布

为满足鄂尔多斯盆地苏里格气田水平井部署、水平井地质导向及跟踪分析的需求,作者运用岩心观察、薄片鉴定、垂向层序和测井相分析等手段,以辫状河沉积模式为指南,汲取有关的露头和现代沉积定量储集层沉积学成果,对苏里格中部水平井开发区盒8下亚段沉积微相和砂体展布进行了精细描述。在相标志、微相特征和沉积层序研究基础上,以研究区密集井区剖面详细对比、砂体储集层厚度统计为依据,并运用水平井水平段录井资料,综合分析估算出研究区盒8下亚段储集砂体规模参数。作者拟定了沉积亚相、微相划分的3项指标(砂/地比、测井曲线、储渗砂体)。精心编制的砂层组沉积微相和砂体展布图,为水平井部署和地质导向提供了有力支撑。     

Fault plane parameters of Sanhe-Pinggu M8 earthquake in 1679 determined using present-day small earthquakes

The great Sanhe-Pinggu M8 earthquake occurred in 1679 was the largest surface rupture event recorded in history in the northern part of North China plain. This study determines the fault geometry of this earthquake by inverting seismological data of present-day moderate-small earthquakes in the focal area. We relocated those earthquakes with the double-difference method. Based on the assumption that clustered small earthquakes often occur in the vicinity of fault plane of large earthquake, and referring to the morphology of the long axis of the isoseismal line obtained by the predecessors, we selected a strip-shaped zone from the relocated earthquake catalog in the period from 1980 to 2009 to invert fault plane parameters of this earthquake. The inversion results are as follows: the strike is 38.23°, the dip angle is 82.54°, the slip angle is -156.08°, the fault length is about 80 km, the lower-boundary depth is about 23 km and the buried depth of upper boundary is about 3 km. This shows that the seismogenic fault is a NNE-trending normal dip-slip fault, southeast wall downward and northwest wall uplift, with the right-lateral strike-slip component. Moreover, the surface rupture zone, intensity distribution of the earthquake and seismic-wave velocity profile in the focal area all verified our study result.     

Active tectonics around the junction of Southwest Japan and Ryukyu arcs: Control by subducting plate geometry and pre‐Quaternary geologic structure

The origin of active faults in the Inner zone of the western part of Southwest Japan was explained by a decrease of the minimum principal stress and reactivation of ancient geologic structures. Although the E–W maximum principal stress in Southwest Japan due to the collision of the Southwest and Northeast Japan arcs along the Itoigawa–Shizuoka Tectonic Line is assumed to decrease westward, the density of active strike‐slip faults increases in the western margin of the Southwest Japan Arc (western Chugoku and northern Kyushu) where the subducting Philippine Sea Plate dips steeply. The E–W maximum compressional stress is predominant throughout Southwest Japan, while the N–S minimum principal stress that is presumably caused by coupling between Southwest Japan arc and Philippine Sea Plate decreases due to the weak plate coupling as the plate inclination increases under the western margin of Southwest Japan. The increase of the fault density in the western margin of the arc is attributed to a decrease of the minimum principal stress and consequent increase of shear stress. Low slip rates of the active faults in this region support the view that the westward increase of fault density is not a response to increasing maximum stress. These faults of onshore and offshore lie in three distinct domains defined on the basis of fault strike. They are defined domains I, II, and III which are composed of active faults striking ENE–WSW, NW–SE, and NE–SW, respectively. Faulting in domains I, II, and III is related to Miocene rift basins, Eocene normal faults, and Mesozoic strike‐slip faults, respectively. Although these active faults are strike‐slip faults due to E–W maximum stress, it is unclear whether their fault planes are the same as those of pre‐Quaternary dip‐slip faults.