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101.
Occurrence and exploration of gas hydrate in the marginal seas and continental margin of the Asia and Oceania region 总被引:5,自引:0,他引:5
Ryo Matsumoto Byong-Jae Ryu Sung-Rock Lee Saulwood Lin Shiguo Wu Kalachand Sain Ingo Pecher Michael Riedel 《Marine and Petroleum Geology》2011,28(10):1751-1767
Supplies of conventional natural gas and oil are declining fast worldwide, and therefore new, unconventional forms of energy resources are needed to meet the ever-increasing demand. Amongst the many different unconventional natural resources are gas hydrates, a solid, ice-like crystalline compound of methane and water formed under specific low temperature and high pressure conditions. Gas hydrates are believed to exist in large quantities worldwide in oceanic regions of continental margins, as well as associated with permafrost regions in the Arctic. Some studies to estimate the global abundance of gas hydrate suggest that the total volume of natural gas locked up in form of gas hydrates may exceed all known conventional natural gas reserves, although large uncertainties exist in these assessments. Gas hydrates have been intensively studied in the last two decades also due to connections between climate forcing (natural and/or anthropogenic) and the potential large volumes of methane trapped in gas hydrate accumulations. The presence of gas hydrate within unconsolidated sediments of the upper few hundred meters below seafloor may also pose a geo-hazard to conventional oil and gas production. Additionally, climate variability and associated changes in pressure-temperature regimes and thus shifts in the gas hydrate stability zone may cause the occurrence of submarine slope failures.Several large-scale national gas hydrate programs exist especially in countries such as Japan, Korea, Taiwan, China, India, and New Zealand, where large demands of energy cannot be met by domestic supplies from natural resources. The past five years have seen several dedicated deep drilling expeditions and other scientific studies conducted throughout Asia and Oceania to understand gas hydrates off India, China, and Korea. This thematic set of publications is dedicated to summarize the most recent findings and results of geo-scientific studies of gas hydrates in the marginal seas and continental margin of the Asia, and Oceania region. 相似文献
102.
老168平台丛式井组是2009年中石化及胜利油田的重点产能建设项目之一,平台上共部署58口海油陆采定向井。该丛式井组的施工主要有以下难点:井网密集,防碰工作量大;造斜点浅、井斜大、造斜困难;位移大、裸眼稳斜段长,稳斜难度大;钻井液技术必须考虑环境保护问题,可借鉴经验非常少。因此钻井施工难度极大,通过实施优化井场布局及井眼轨道技术、大井眼松软浅地层定向技术、高精度轨迹控制技术、大位移井安全钻进技术,优质无污染海水钻井液技术,最终实现了老168钻完井一体化作业,节约了成本,提高了效率,为今后胜利油田丛式井组施工提供了宝贵经验。 相似文献
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The trophic ecology of the small yellow croaker (Larimichthys polyactis) was studied using stable isotope analyses. Samples were collected from July to September 2009 and 34 individuals from eight sites were examined for stable carbon and nitrogen isotopes. Stable carbon isotope ratios (δ13C) ranged from -20.67 to -15.43, while stable nitrogen isotope ratios (δ15N) ranged 9.18-12.23. The relationship between δ13C and δ15N suggested high resource partitioning in the sampling area. Significant differences in stable isotope values among the eight sampling sites may be linked to environmental diversities involving various physical processes (such as ocean current, wind and tide) and different carbon sources. Furthermore, the stable isotope ratios may also explain the ontogenetic variability in diet and feeding, because δ13C and δ15N varied significantly with increasing body size. The findings are consistent with other studies on diet analyses in small yellow croaker. It was also demonstrated that stable isotope analysis could be used to estimate the trophic characters of small yellow croaker in feeding patterns and migrating habits. 相似文献
107.
在对深部煤田地质钻孔钻进工艺研究的基础上,有针对性选择使用聚合物泥浆,解决了基浆配制用水及泥浆抗地表水水质污染问题。通过改变双管钻具长度和改换取心钻头的切削具,满足软硬互层对钻头钻进效率的影响。在煤系地层钻进中,除采用常规的单管钻具钻进外,在见煤预告下过后,采用加长双管取心钻具,既可保证了回次进尺,又可保证岩心的采取。多项措施落实,不仅解决了生产中的一些难题,收到了较好的效果,而且创造了河北省煤田地质局煤田地质单孔钻探深度2 009.12m的新纪录,为今后深部钻孔的施工积累了经验。 相似文献
108.
路堤荷载下碎石桩处理软基沉降计算 总被引:1,自引:0,他引:1
以沉降控制为目的的碎石桩复合地基,其沉降计算在设计、施工中具有重要地位。本文基于典型的桩土单元体模型,建立了复合地基体积压缩系数与复合地基弹性模量的关系,考虑施工中的时间因素及相应的固结度对沉降的影响,提出相应的沉降计算公式,并结合四川省遂-资高速公路软基变形监测的数据进一步验证其可行性。研究表明本算法计算值比实测沉降约大10% ~20%。填筑过程中,计算沉降历时曲线与实测曲线拟合较好,更接近实测值;在此基础上,初步探讨了影响路堤荷载下碎石桩处理软基沉降变化的因素,得出桩径、桩间距对其影响较为明显。同时结合本例,建议布桩时桩间距与桩径比值最好控制在2~4之间。 相似文献
109.
The process of drilling, in general, always produces sound. Though sound is used as a diagnostic tool in mechanical industry, its application in predicting rock property is not much explored. In this study, an attempt has been made to estimate rock properties such as uniaxial compressive strength, Schmidt rebound number and Young's modulus using sound level produced during rotary drilling. For this purpose, a computer numerical controlled vertical milling centre was used for drilling holes with drill bit diameters ranging from 6 to 20 mm with a shank length of 40 mm. Fourteen different rock types were tested. The study was carried out to develop the empirical relations using multiple regression analysis between sound level produced during drilling and rock properties considering the effects of drill bit diameter, drill bit speed and drill bit penetration rate. The F-test was used to check the validity of the developed models. The measured rock property values and the values calculated from the developed regression model are fairly close, indicating that the developed models could be efficiently used with acceptable accuracy in prediction of rock properties. 相似文献
110.