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31.
绳索取心钻探时,斜孔钻进发生的埋钻事故较难处理,在松软易碎地层中埋钻事故又极难预防。经多年实践,提出事故发生后采取优化钻孔井身结构,结合爆破法处理有效省时,节约成本又减少损失。 相似文献
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Determination of the origin of mineralization and groundwater salinity in the Adrar region in the southwest of Algeria 下载免费PDF全文
KHELFAOUI Hakim DAJBRI Larbi LAKHAL Fatima Zohra CHAFFAI Hicham HANI Azzedine SAYAD Lamine 《地下水科学与工程》2020,8(2):158-171
To some extent, the sedimentary sequence with the largest groundwater reserves in northern Sahara is marked by a certain water table level, regionally known as the "Continental Intercalaire"(CI). "Continental Intercalaire"(CI) refers to "Continental Intercalary" widely distributed among three countries. Algeria, Tunisia and Libya, which have significant potential of water resources. As it is the only water resource relatively easily accessible to the inhabitants of the Sahara, it is widely developed. The physico-chemical characteristics of statistical processing in principal component analysis(PCA) and the chemical phase measurement of groundwater in the unconfined aquifer captured by "Foggaras"(traditional system irrigation composed of well system linked by a horizontal channel from their bases) and the deep drillings located in the study area were accessible. Therefore, there were some favorable conditions for comparing the chemistry of these waters with the standards of potability established by the World Health Organization. Then, the study detected the origin of excessive mineralization and the excessive content of Na, Cl, K, Mg and Ca that originated from the leaching of the clay and carbonate layers of the "Continental Intercalaire". In addition, the enrichment in NO_2~-, NO_3~- and SO_4~(2-) was due to the excessive use of fertilizer in the whole region for shallower Foggaras waters, and this study also showed the dominant chemical facies of groundwater related to the significant abundance of these mineral salts in this thick aquifer horizon. 相似文献
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通过对南海大洋钻探ODP第184航次的ODP1143站和ODP1146站以及中德合作"太阳号"95航次的南沙海区17957-2柱状样中微体化石进行定量分析,提取了近18MaB.P.以来南海上部海水垂向结构的变化.结果发现11.5~10.6MaB.P.之间和3.6~3.3MaB.P.以来南海温跃层深度的南北梯度明显增大,指示了西太平洋暖池雏形的开始和现代暖池的最终形成,且分别对应于印度尼西亚海道和巴拿马地峡的关闭.此后,南沙海区的温跃层深度自约0.9MaB.P.逐渐变浅,至约0.15MaB.P.又再变深,反映了西太平洋暖池的减弱和再次加强.因而,晚新生代西太平洋暖池的形成和演化呈现阶段性. 相似文献
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Holdway DA 《Marine pollution bulletin》2002,44(3):185-203
A review of the acute and chronic effects of produced formation water (PFW), drilling fluids (muds) including oil-based cutting muds, water-based cutting muds, ester-based cutting muds and chemical additives, and crude oils associated with offshore oil and gas production was undertaken in relation to both temperate and tropical marine ecological processes. The main environmental effects are summarized, often in tabular form. Generally, the temporal and spatial scales of these studies, along with the large levels of inherent variation in natural environments, have precluded our ability to predict the potential long-term environmental impacts of the offshore oil and gas production industry. A series of critical questions regarding the environmental effects of the offshore oil and gas production industry that still remain unanswered are provided for future consideration. 相似文献
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A cell powder factor defines the local powder factor in a simple geometric procedure that accounts for the charge in each blast hole and the triangulation formed by blast hole collars in a blast pattern. In the case of asymmetric blast patterns, the cell powder factor deviates from the global powder factor. Poor drilling of blast hole collars produces significant variation in the cell powder factor, more so, than does poor blast hole charging. The cell powder factor does not account for timing within a blast and does not easily handle non-parallel blast hole configurations. The cell powder factor is best used as a design or audit tool before blast holes are loaded. It gives the opportunity to correct for poor drilling and/or poor charging practices prior to firing a blast. 相似文献
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Generation of Porphyritic and Equigranular Mafic Enclaves During Magma Recharge Events at Unzen Volcano, Japan 总被引:5,自引:0,他引:5
BROWNE BRANDON L.; EICHELBERGER JOHN C.; PATINO LINA C.; VOGEL THOMAS A.; DEHN JONATHAN; UTO KOZO; HOSHIZUMI HIDEO 《Journal of Petrology》2006,47(2):301-328
Mafic to intermediate enclaves are evenly distributed throughoutthe dacitic 19911995 lava sequence of Unzen volcano,Japan, representing hundreds of mafic recharge events over thelife of the volcano. This study documents the morphological,textural, chemical, and petrological characteristics of theenclaves and coexisting silicic host lavas. The eruptive productsdescribed in this study appear to be general products of magmamingling, as the same textural types are seen at many othervolcanoes. Two types of magmatic enclaves, referred to as Porphyriticand Equigranular, are easily distinguished texturally. Porphyriticenclaves display a wide range in composition from basalt toandesite, are glass-rich, spherical and porphyritic, and containlarge, resorbed, plagioclase phenocrysts in a matrix of acicularcrystals and glass. Equigranular enclaves are andesitic, non-porphyritic,and consist of tabular, medium-grained microphenocrysts in amatrix glass that is in equilibrium with the host dacite magma.Porphyritic enclaves are produced when intruding basaltic magmaengulfs melt and phenocrysts of resident silicic magma at theirmutual interface. Equigranular enclaves are a product of a moreprolonged mixing and gradual crystallization at a slower coolingrate within the interior of the mafic intrusion. KEY WORDS: mafic enclaves; quenched mafic inclusions; magma mingling; Unzen volcano; Unzen Scientific Drilling Project; resorbed plagioclase 相似文献
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深海钻探计划(DSDP)和大洋钻探计划(ODP)实施以来促进了地层学的发展。通过对大洋沉积物的研究,利用生物属,种的始,末现面事件建立起了晚中生代-新生代高精度的钙质超微化石,有孔虫,放射虫以及沟鞭藻的化石带,综合利用这些基准面事件,可使地层划分精度达10万年以内。使用液压活塞取心技术,建立起了完整,连续的中,新生代磁性地层剖面,加之放射性年龄的测定,确定了数百个生物属,种始,末现面的绝对年龄值, 相似文献
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大洋钻探与全球变化(二)——从海洋角度研究第四纪古全球变化 总被引:1,自引:0,他引:1
海洋在第四纪全球气候和环境的变化中起着至关重要的作用,一方面,海洋沉积记录了大量第四纪古全球变化的信息,特别是可提供古球变化中高分辨率的短期气候事件的记录,另一方面,无论是全球性大洋环流,生物和化学的变化,还是区域性西太平洋边缘海浅水陆架的出没,这些海洋事件都可能是许多第四纪古全球变化现象的原因之所在。因此,从海洋角度研究第四纪古全球变化,已成为当前古全球变化和国际古海洋学研究的重点。在这方面,深 相似文献