Numerical simulation of LWD resistivity response of carbonate formation using self-adaptive hp-FEM

Most of the carbonate formation are highly heterogeneous with cavities of different sizes, which makes the prediction of cavity-filled reservoir in carbonate rocks difficult. Large cavities in carbonate formations pose serious threat to drilling operations. Logging-whiledrilling （LWD） is currently used to accurately identify and evaluate cavities in reservoirs during drilling. In this study, we use the self-adaptive hp-FEM algorithm simulate and calculate the LWD resistivity responses of fracture-cavity reservoir cavities. Compared with the traditional h-FEM method, the self-adaptive hp-FEM algorithm has the characteristics of the self-adaptive mesh refinement and the calculations exponentially converge to highly accurate solutions. Using numerical simulations, we investigated the effect of the cavity size, distance between cavity and borehole, and transmitted frequency on the LWD resistivity response. Based on the results, a method for recognizing cavities is proposed. This research can provide the theoretical basis for the accurate identification and quantitative evaluation of various carbonate reservoirs with cavities encountered in practice.

怎样杜绝产生“懒蟹”

所谓“懒蟹”是指栖居在远离水面的穴洞里懒得出来活动觅食、个体奇小的蟹。由于它的个体最小,严重影响河蟹的产量,使经济效益低下。产生懒蟹的原因有以下四点: 第一,养殖水体溶氧太低。河蟹对水体溶氧的要求高于5毫克/升,当水中溶氧低于4毫克/升时,河蟹在水中就感到不舒适。

An Observation of Franois' Langurs Using Caves at Mayanghe National Nature Reserve, Guizhou, China

The utilization of caves is a rather rare phenomenon in nonhuman primates, found almost exclusively in those members of the genus Trachypithecus that share a preference for forest on limestone （karst） hills in Vietnam and southern China. Here we report a new case of usage of caves as overnight sleeping shelters by Franqois＇ or black langurs （Trachypithecusfraru;oisi） at Mayanghe National Nature Reserve in Yanhe County, Guizhou Province, China. We tentatively address three possible hypotheses that may account for the use of caves in Francois＇ langurs at Mayanghe： shelter against climatic conditions, acquisition of minerals and protection from predators. utilization

3D cavity detection technique and its application based on cavity auto scanning laser system

Ground constructions and mines are severely threatened by ones. Safe and precise cavity detection is vital for reasonable cavity underground cavities especially those unsafe or inaccessible evaluation and disposal. The conventional cavity detection methods and their limitation were analyzed. Those methods cannot form 3D model of underground cavity which is used for instructing the cavity disposal; and their precisions in detection are always greatly affected by the geological circumstance. The importance of 3D cavity detection in metal mine for safe exploitation was pointed out; and the 3D cavity laser detection method and its principle were introduced. A cavity auto scanning laser system was recommended to actualize the cavity 3D detection after comparing with the other laser detection systems. Four boreholes were chosen to verify the validity of the cavity auto scanning laser system. The results show that the cavity auto scanning laser system is very suitable for underground 3D cavity detection, especially for those inaccessible ones.

Karst Cave Tourism System in Zhejiang Province Based on Resource Regional Analysis

Karst cave tourism plays an important role in the overall tourism of Zhejiang Province, China. In analyzing the current status of karst cave tourism resources, it is crucial to develop a scientific system for optimizing resource exploitation and tourism development in the future. This study conducted an analysis of resource characteristics and regional structure in Zhejiang Province. Nearest neighbor index （NNI） method and accessibility index method were used for a comprehensive understanding of the effects of scale, strength, combination, and accessibility of karst cave tourism resources. Results indicated that karst cave tourism resources in Zhejiang Province have a significant regional influence, and that resource quality and exploitation are diverse in different regions. Among the regions, Jinhua had the highest exploitation proportion of over 60% and the lowest NNI value of 0.098. Furthermore, regional analysis inferred that different karst caves demonstrate diversity in accessibility to tourism markets, among which the Lingshan Cave, Fengshui Cave, and Xianqiao Cave reveal the highest accessibility index of 2.41. Finally, we put forward a karst cave tourism system in Zhejiang Province based on the Growth Pole Theory and set up an overall scheme for karst cave tourism development. From a regional perspective analysis, the study refined the methods for regional resource re- search and provided a strategic proposal for karst cave tourism in Zheiiang Province.

Catastrophe analysis of deep tunnel above water-filled caves

To explore the influence of karst cavity pressure on the failure mechanisms of rock layers above water-filled caves, novel blow-out and collapse mechanisms are put forward in this study. The proposed method uses the nonlinear optimization to obtain the failure profiles of surrounding layered rock with water-filled cave at the bottom of the tunnel. By referring to the functional catastrophe theory, stability analysis with different properties in different rock layers is implemented with considering the incorporation of seepage forces since the groundwater cannot be ignored in the catastrophe analysis of deep tunnel bottom. Also the parametric analysis is implemented to discuss the influences of different rock strength factors on the failure profiles. In order to offer a good guide of design for the excavation of deep tunnels above the water-filled caves, the proposed method is applied to design of the minimum effective height for rock layer. The results obtained by this work agree well with the existing published ones.

Influences of air CO2 on hydrochemistry of drip water and implications for paleoclimate study in a stream-developed cave, SW China

Cave air CO_2 is a vital part of the cave environment. Most studies about cave air CO_2 variations are performed in caves with no streams; there are few studies to date regarding the relationship of cave air CO_2 variations and drip water hydrochemistry in underground stream–developed caves. To study the relationship of underground stream, drip water, and cave air CO_2, monthly and daily monitoring of air CO_2 and of underground stream and drip water was performed in Xueyu Cave from 2012 to 2013.The results revealed that there was marked seasonal variation of air CO_2 and stream hydrochemistry in the cave. Daily variations of cave air CO_2, and of stream and drip water hydrochemistry, were notable during continuous monitoring.A dilution effect was observed by analyzing hydrochemical variations in underground stream and drip water after rainfall. High cave air CO_2 along with low p H and low δ^(13)C DIC in stream and drip water indicated that air CO_2 was one of the dominant factors controlling stream and drip water hydrochemistry on a daily scale. On a seasonal scale, stream flows may promote increased cave air CO_2 in summer; in turn, the higher cave air CO_2 could inhibit degassing of drip water and make calcite δ^(13)C more negative. Variation of calcite δ^(13)C(precipitated from drip water) was in reverse of monthly temperature, soil CO_2, and cave air CO_2. Therefore,calcite δ^(13)C in Xueyu Cave could be used to determine monthly changes outside the cave. However, considering the different precipitation rate of sediment in different seasons,it was difficult to use stalagmites to reconstruct environmental change on a seasonal scale.

FGC-15D large-diameter DTH air hammer drilling system and its application in offshore rock-socketed pile hole drilling

In the past two decades, numerous large-diameter rock-socketed piles were constructed in China to support foundations of skyscrapers, great bridges or to retain soil in potential geological hazard areas. However, drilling large-diameter rock-socketed pile holes with conventional drilling method such as rotary drilling or cable tool drilling is time-consuming and the cost is usually very high. In order to drill large-diameter rocksocketed pile holes faster at relatively low cost, the FGC15A large-diameter DTH air hammer drilling system was developed in 1987 and was given the second-clasa award by Ministry of Geology and Mineral Resources in 1991. Since it was innovated the drilling system has been used in more than twenty important and tough pro- jects on land, and wonderful results were acquired. At the same time the large-diameter DTH air hammer drilling system was improved continuously. The FGC15D is the latest version of the technique.

Effects of Urechis unicinctus Juveniles on Chemical Characteristics of Organically Contaminated Coastal Sediment

Biological activities of marine benthos such as burrowing and feeding may change sediment characteristics.We conducted three experiments to examine the potential of using juveniles of a spoon worm Urechis unicinctus to improve the quality of organically contaminated coastal sediment.Sediment samples were collected from a site that was heavily contaminated with organic matter (Seonso) and two sites that were clean (Myo-do,Dolsan-do).Urechis juveniles,obtained by artificial fertilization and cultured in the laboratory,were introduced to the sediment (weight 3 kg,depth 10 cm) at a density of 500 individuals per aquarium (length 50 cm,width 35 cm,height 30 cm) (Experiment 1),or at densities ranging from 100 to 900 individuals per beaker (Experiment 2).To examine how sediment contamination can be modified by the effects of Urechis,500 individuals (per aquarium) were exposed to the Seonso contaminated sediment that had been mixed with 0-100% clean sand (Experiment 3).Each experiment lasted two months and sediment samples were collected every 15 d to determine the several indexes of sediment quality,which included acid volatile sulfide (AVS),chemical oxygen demand (COD) and total ignition loss (TIL).In Experiment 1,the existence of Urechis did not result in significant changes in quality indexes in the sediments collected from Myo-do,Dolsan-do.However,AVS,COD and TIL of the Seonso sediment all decreased significantly after co-incubation with Urechis juveniles for 30 to 45 d.Experiment 2 showed that a density of at least 300 juveniles per beaker was necessary to significantly reduce all three quality indexes,and the magnitude of reduction was positively correlated with juvenile density.Experiment 3 revealed that Urechis juveniles were effective in reducing the AVS,COD and TIL of the Seonso sediment that had been mixed with 60%,80%,and 80% of clean sand,respectively.The results of the present study therefore indicated that juveniles of this spoon worm have the potential to be used to improve the quality of organically contaminated sediment in coastal waters.

Effect of soil-rock system on speleothems weathering in Bailong Cave,Yunnan Province,China

Bailong Cave with its well-developed Middle Triassic calcareous dolomite’s system was opened as a show cave for visitors in 1988. The speleothem scenery has been strongly weathered as white powder on the outer layers. Study of the cave winds, permeability of soil-rock system and the chemical compositions of the dripping water indicated: (1) The cave dimension structure distinctively affects the cave winds, which were stronger at narrow places. (2) Based on the different soil grain size distribution, clay was the highest in composition in the soil. The response sense of dripping water to the rainwater percolation was slow. The density of joints and other openings in dolomite make the dolomite as mesh seepage body forming piles of thin and high columns and stalactites. (3) Study of 9 dripping water samples by HYDROWIN computer program showed that the major mineral in the water was dolomite.

Cave Environmental Changes： The Possibilities of Assessment

The aim of this research is to apply a new approach to assess cave environmental changes--CDI （cave disturbance index）, based on the five main categories： geomorphology, hydrology, atmosphere, biology and culture. The indicators of every category are considered in detail. The quantitative estimation of total CDI is proposed.

The hydrologic record of karst systems: linking soil moisture to the carbon isotope signatures of soils above the Blue Spring cave system

Speleothem carbonates are precipitated continuously from inorganic carbon dissolved in seepage water infiltrating from the land surface,that reflects a mixture of atmospheric CO_2,respired soil carbon,and epikarst sources,each with distinct δ^(13)C values.To aid in deconvolving these signatures,soil samples were collected above the Blue Spring cave system in Sparta,Tennessee,USA and subjected to a series of incubation experiments,in order to constrain the correlation between CO_2respiration rates and soil moisture.This relationship is used to parameterize a simple mixing model which predicts the relationship between δ^(13)C and soil moisture in fluids infiltrating into the underlying cave system.

Biological Community in Submerged Caves and Marine Lakes in ha Long-Cat Ba Area, Vietnam

Submerged caves and marine lakes are two iconic and common ecosystems in Ha Long-Cat Ba area. However, their biological characteristics are poorly known since very limited studies have been conducted, The aim of this study was to investigate biodiversity in these ecosystems. Three submerged caves （Hang Sang, Hang Toi and Qua Bang） and three marine lakes （Dau Be, Ang Du and Qua Bang） were chosen for study. The results showed that organism communities in submerged caves were abundant with over 142 species found. The popular groups comprised sponge and soft coral which were distributed along the length of the caves. Several species with high economic value were widespread in the caves, including stone crab Myomenippe hardwickii, flower crab Portunus pelagicus, cone snails Trochus pyramis, shoemaker spinefoot Siganus sutor, snapper Lutjanus russellii. Species that permanently live in caves were not detected. In the lakes where water is well exchanged to the sea, coral reefs were found and they usually formed a narrow band around the lakes. Sandy beaches were often observed around the lakes at the depths of 0.5-2 m, containing specialty species as clam （Sanguinolaria diphos）, snout otter clam （Lutraria rhychaena）, sea cucumbers with high density （in Dau Be, Qua Bang）. There was no coral reef in the enclosed lake （Ang Du） because of low salinity.

Feeding Group Zonation of Ephemeroptera （Insecta） at Plalar-Gremeng River, Gunung Sewu Karst Ecosystem, Gunungkidul, Yogyakarta Special Province, Indonesia

The objectives of this research were to record the changes in composition of the community of ephemeroptera in Plalar-Gremeng river, examine the causes of these changes and discover their significance in the life of the rivers. The ephemeropteran community and abundance of the feeding group （detritivore, gatherer and scrapper） were compared with the nutrient and water quality of each sampling site. It is established that, under site conditions, nutrient status can be regarded as the chief internal factors. The method was field survey for sampling the substrate at five sites： （I） Up-stream of Plalar river; （2） The site before the Plalar cave; （3） The total dark zone of Plalar-Gremeng caves; （4） The site after Gremeng cave and （5） The down-stream of Gremeng to Beton river. Substrate sampling used Surber benthic sampler and the sample was containing and labeling. Environmental parameters were measured water temperature, carbon dioxide, velocity, pH, C-organic, sediment total-phosphorus and nitrogen and Ca content. The data was analyzed by description. The results showed that the abundance of ephemeroptera was highest at site-4 and the lowest at site-3. Ephemeropthera play a highly important role in preserving nutrient status.

Monitoring Climatic Changes and Carbon Cycle in Canyons and Caves： The C6 Project

The acronym C6 means ＂Climatic Changes and Carbon Cycle in Canyons and Caves＂. It is a monitoring project, for the evaluation of climate change signals, based on measuring sites located inside canyons and caves; it merged in the year 2005, under the scientific supervision of the Palermo Branch of the Italian National Institute for Geophysics and Volcanology （INGV）, two different monitoring programs active since 1999. The choice of these environments is based on their morphological structure： being them more or less segregated respect the outer atmosphere, they act as low-pass filters respect the variations of the monitored parameters, which are rainfall and dropping water amounts and rates, air temperatures and relative humidity and carbon dioxide concentrations in the atmosphere. On the basis of the preliminary data, reported and discussed in the paper, the C6 network seems to be capable to give useful information on the local effects of global changes, even if at the moment the monitored parameters concern only the abiotic components of the studied ecosystems.

西安市南郊上塔坡村东战国秦汉墓发掘简报

2019年12月至2020年5月,西安市文物保护考古研究院联合四川大学考古文博学院在西安市南郊上塔坡村东进行了考古发掘,共清理墓葬61座,其中战国至汉代墓葬34座,出土陶鼎、盒、蒜头壶、灶、罐、甑、盆、缶、灯、璧以及铁削、石串珠、铜钱等大量遗物。这批墓葬保存较好,出土器物的组合关系明确,部分墓葬出土陶器上还多戳印“杜亭”陶文,为完善关中地区战国至秦汉之际考古学文化序列,探索秦汉时期杜县周边丧葬习俗及社会组织形态的变迁提供了重要材料。

Seismic identification and characterization of complex storage space oil and gas reservoirs

To predict complex reservoir spaces(with developed caves,pores,and fractures),based on the results of full-azimuth depth migration processing,we adopted reverse weighted nonlinear inversion to improve the accuracy of porous reservoir prediction.Scattering imaging three-parameter wavelet transform technology was used to accurately predict small-scale cave bodies.The joint inversion method of velocity and amplitude anisotropy was developed to improve the accuracy of small and medium-sized fracture prediction.The results of multiscale fracture modeling and characterization,interwell connectivity analysis,and connection path prediction are consistent with the production condition.Finally,based on the above prediction findings,favorable reservoir development areas were predicted.The above ideas and strategies have great application value for the efficient exploration and development of complex storage space reservoirs and the optimization of high-yield well locations.

江苏徐州市奎山四座西汉墓葬

2005年8月,徐州博物馆在徐州市南郊西奎山北麓清理了4座西汉时期夫妻同穴合葬墓。其中M9、M10为石坑竖穴墓,竖穴底部并列葬夫妻二人;M11、M12为石坑竖穴洞室墓,竖穴底部及洞室内均葬有人。墓葬虽遭盗扰,但仍出有陶器、原始瓷器、铜器、铁器、漆木器、玉石器等。4座墓分布较为集中,应为同一家族墓葬。

江苏徐州市大孤山二号汉墓

2004年4月,徐州博物馆对江苏徐州市区西北大孤山北麓的大孤山二号汉墓进行发掘。该墓为石坑竖穴洞室墓,竖穴底部有一地位稍低的合葬者,洞室位于竖穴西侧,内葬夫妻二人。随葬品较丰富,有陶器、铜器、漆器、玉器、铁器、龟钮玉印和铜印等。大孤山二号汉墓的时代应为西汉中期,墓主应为级别较高的官吏。