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1.
针对深渊生物资源研究的需求，自主研发了用于全海深深度的深渊沉积物、水体和宏生物的保压取样装置，深渊沉积物保压转移装置，深渊微生物原位过滤及保存装置和高压培养高压酶学测定装置。在深海模拟环境验证了取样装置在万米深度下的工作性能。相关装置在“探索一号”科考船的TS15、TS21-1和TS21-2大洋科考航次中，搭载“奋斗者”号载人潜器、“2号”深渊着陆器、“原位实验”号着陆器于西菲律宾盆区和马里亚纳海沟进行了海上试验，成功获取了万米深度沉积物、水体和宏生物保压样品以及微生物原位过滤滤膜；成功进行了沉积物保压样品的保压转移试验。初步形成了深渊海域生物资源取样的装备技术体系，为深渊海底生物和基因资源开发，深渊生命过程等科学研究提供技术手段。 相似文献
2.
Jui-Hsien Wang Wu-Cheng Chi R. Nigel Edwards Eleanor C. Willoughby 《Marine Geophysical Researches》2010,31(1-2):99-107
Gas hydrates affect the bulk physical properties of marine sediments, in particular, elastic parameters. Shear modulus is an important parameter for estimating the distribution of hydrates in the marine sediments. However, S-wave information is difficult to recover without proper datasets. Seafloor compliance, the transfer function between pressure induced by surface gravity waves and the associated seafloor deformation, is one of few techniques to study shear modulus in the marine sediments. The coherence between recorded time series of displacement and pressure provides a measure of the quality of the calculated transfer function, the seafloor compliance. Thus, it is important to understand how to collect high coherence datasets. Here we conducted a 10-month pilot experiment using broadband seismic sensors and differential pressure gauges. We found that data collected in shallow water depth and during rough seas gave high coherence. This study is the first time long-term data sets have been employed to investigate seafloor compliance data quality and its dependence on sea state. These results will help designing future large-scale compliance experiments to study anomalously high shear moduli associated with the presence of gas hydrate or cold vents, or alternatively anomalously low shear moduli, associated with partial melt and magma chamber. 相似文献
3.
针对深海运载器海底岩芯原位取样作业需求,对基于水下运载器的深海原位取芯钻机在深海低温、高压、底层流速多变等特点条件下的作业机理及受力进行分析,并选取硬质合金钻头和PDC钻头进行了取芯钻头的轴向力、切向力和切削功率的数学力学对比计算,确定了单环四齿周向均布的金刚石复合片(PDC)钻头设计方案。在理论分析基础上,针对深海钴结壳设计了台架试验,开展钻进试验研究。通过理论计算和实验研究,探寻了一种基于深海运载器的钴结壳小型钻机设计方法,确定了钻机功率、转速、钻进正向压力和取芯率等基本参数选取范围,对开展海底岩芯原位取样作业具有重要的指导意义。 相似文献
4.
This paper describes studies of the effect of hydrate dissociation on the safety and stability of methane hydrate-bearing sediments. Methane hydrates within the sediments were dissociating under the conditions of a confining pressure of 0.5 MPa, 1 MPa, 2 MPa and a temperature of −5 °C. After 6 h, 24 h, or 48 h, a series of triaxial compression tests on methane hydrate-bearing sediments were performed. The tests of ice-clay and sediments without hydrate dissociation were performed for comparison. Focusing on the mechanical properties of the sediments, the experimental results indicated that the shear strength of the ice-clay mixtures was lower than that of the methane hydrate-bearing sediments. The strength of the sediments was reduced by hydrate dissociation, and the strength tended to decrease further at the lower confining pressures. The secant modulus ES of the sediments dropped by 42.6% in the case of the dissociation time of the hydrate of 48 h at the confining pressure of 1 MPa; however, the decline of the initial yield modulus E0 was only 9.34%. The slower hydrate dissociation rate contributed to reducing the failure strength at a declining pace. Based on the Mohr–Coulomb strength theory, it was concluded that the decrease in strength was mainly affected by the cohesive reduction. Moreover, the mathematical expression of the M–C criterion related to the hydrate dissociation time was proposed. This research could be valuable for the safety and stability of hydrate deposits in a permafrost region. 相似文献
5.
Lauer-Leredde Christine Pezard Philippe A. Dekeyser Ivan 《Marine Geophysical Researches》1998,20(2):95-107
Physical properties of shallow sediments measured at a particular site can not easily be extrapolated over a given profile. The number of samples required to define sediment properties adequately can then become time-consuming and expensive. Laboratory and in-situ experimentations have shown that electrical probing provides a useful complementary technique to extrapolate results from cores. These experiments have pointed out the need for quantitative, easily-transportable and fast resistivity measurements combining high vertical resolution with azimuthal resolution and full coverage, in the shallow subsurface. A new prototype probe called FICUS (Formation Imaging and Coring for Unconsolidated Sediments) has been developed to bridge this gap. FICUS is designed to provide in-situ high resolution electrical resistivity images of the upper few meters of shallow unconsolidated sediments.Laboratory experiments have been completed to test the feasibility of this technique to provide resistivity images of unconsolidated sediments. Laboratory images agree with theoretical predictions from numerical modelling. The obtained cm-scale resolution could be used for petrophysical and sedimentary purposes. The probe may offer additional information about changes in porosity and pore morphology caused by climatic cycles, since electrical resistivity is known to be especially sensitive to these changes. The probe could also allow to detect and map organic pollutants in the future. 相似文献
6.
The paper presents the design and preliminary test results of a corer used for hard seafloor sediments sampling.Generally the sediment cores are provided by either gravity-type coring or deep-ocean drilling for a range of studies.However,in consideration of the operability and available sample length in collecting hard sediments,these methods exhibit no advantages.In this paper,a new corer which can exploit both hydrostatic energy and gravity energy for hard sediments coring is presented.The hydrostatic energy is provided by pressure differential between ambient seawater pressure and air pressure in an empty cavity.During sampling process,the corer penetrates into the sediment like a gravity corer and then automatically shifts to the percussion mode.The experiments in the laboratory indicate that the corer can complete 40 cycles in the sea with a cycle time of 2.8 seconds in percussion mode and impact the sample tube with the velocity of 0.2 m/s during each cycle.Besides,its adjustable falling velocity can make the corer achieve the maximum efficiency in coring different sediments. 相似文献
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8.
An energy conversion system based on deep-sea pressure 总被引：1，自引：0，他引：1
A novel seawater pressure energy conversion system that utilizes seawater pressure to generate electricity has been studied in this paper. The energy conversion system utilizes the pressure difference between the pressurized seawater and the empty pressure container to drive hydraulic motor and the coaxially coupled generator to generate electric power. The output electric energy is recorded by the data logger throughout the process. In the current study, technical analysis is performed with the emphasis on conversion efficiency between seawater pressure energy and output electric energy. The analysis is conducted at various pressure differences through the throttle valve so as to obtain maximum conversion efficiency. Research shows that the optimum pressure difference through the throttle valve and the maximum conversion efficiency can be theoretically calculated when the properties of the conversion system are given. Simulation results have demonstrated the influence of pressure difference on conversion efficiency. The test apparatus has been designed, built and tested in 2004. It successfully generated electric energy of approximately 0.85 kW h at the depth of 2400 m with empty pressure container's holding capacity of 200 L in the voyage “DY105-16” in South China Sea on June 12, 2004. The actual conversion efficiency from seawater pressure energy to electric energy reaches as high as 63.8% which is attractive for underwater equipments. The success of the experiment has tested the feasibility of utilizing seawater pressure energy and brings a new power supply way for long-term in-situ underwater equipments. 相似文献
9.
天然气水合物的重要特征与评价及其在中国海域的勘探前景 总被引：1，自引：0，他引：1
从勘探技术和资源评价的角度综述了甲烷水合物生成和聚集的重要特征, 如地震反射剖面、测井曲线资料、地球化学特点等以及对未知区的地质勘探和选区评价 .甲烷水合物在地震剖面上主要表现为BSR(似海底反射)、振幅变形(空白反射)、速度倒置、速度-振幅结构(VAMPS)等,大规模的甲烷水合物聚集可以通过高电阻率(＞100欧姆.米)声波速度、低体积密度等号数进行直接判读.此项研究实例表明,沉积物中典型甲烷水合物具有低渗透性和高毛细管孔隙压力特点,地层孔隙水矿化度也呈异常值,并具有各自独特的地质特征.现场计算巨型甲烷水合物储层中甲烷资源量的方法可分为:测井资料计算法公式为:SW＝(abRw/φm.Rt)1/n;地震资料计算法公式为:ρp＝(1-φ)ρm+(1-s)φρw+sφρh、VH＝λ.φ.S.对全球甲烷水合物总资源量预测的统计达20×1015m3以上.甲烷水合物形成需满足高压、低温条件,要求海水深度＞300 m.因此,甲烷水合物的分布严格地局限于两极地区和陆坡以下的深水地区,并具有3种聚集类型:1.永久性冻土带;2.浅水环境;3.深水环境.深海钻探计划(DSDP)和大洋钻探计划(ODP)已在下述10个地区发现大规模的甲烷水合物聚集,他们是:秘鲁、哥斯达黎加、危地马拉、墨西哥、美国东南大西洋海域、美国西部太平洋海域、日本海域的两个地区、阿拉斯加和墨西哥湾地区.在较浅水沉积物岩心样中发现甲烷水合物的地区,包括黑海、里海、加拿大北部、美国加里福尼亚岸外、墨西哥湾北部、鄂霍茨克海的两个地区.在垂向上,甲烷水合物主要分布于海底以下2 000 m以浅的沉积层中.最新统计表明又主要分布于二个深度区间:200～450 m和700～920 m,前者是由ODP995～997站位发现的;后者在加拿大麦肯齐河三角洲马立克2L-38号井中897～922 m处发现.中国海域已发现多处甲烷水合物可能赋存地区,包括东沙群岛南部、西沙海槽北部、西沙群岛南部以及东海海域地区.姚伯初报道了南海地区9处地震剖面速度异常值的发现,海水深度为420～3 920 m,海洋地质研究所则在东海海域解释了典型BSR反射的剖面,具有速度异常、弱振幅、空白反射、与下伏反射波组具不整合接触关系(VAMPS)等,大致圈定了它们的分布范围,表明在中国海域寻找甲烷水合物具有光明的前景. 相似文献
10.
海底沉积物的声学测量是海底测深的关键技术之一,应用于海底地形地貌测量、海洋矿产资源开采和海底工程建设等。海底沉积物声学测量方法中的原位测量方法可以避免保真采样法的强扰动性和遥测法的准确度、精度及灵敏度的不确定性等缺点,如何改进原位测量系统渐成为海底探测的研究热点。通过分析现有海底沉积物原位测量设备测试换能器的工作原理,针对垂直压入方式换能器测量深度有限,提出了一种通过改变换能器压入沉积物的角度来增加测量深度的方法。在理论上论证出在不低于换能器接收阈值时,测量深度随着掠射角的增加而增加。在不增加压入深度的前提下提供了一种增加测量深度方法。 相似文献
11.
为了研究黄河口海床沉积物固结过程中电阻率同工程力学性质指标的对应关系,探索海床土体固结过程的新型原位监测技术,本文在黄河刁口流路三角洲叶瓣潮坪上,现场取土配置黄河口快速沉积形成的流体状沉积物和观测研究粉质土海床的固结过程。利用静力触探、十字板剪切试验、孔隙水压力监测等原位土工测试手段,实时测定固结过程中海床土强度变化和孔隙水压力消散过程;同时通过埋置自行研制的环形电极探杆,实时测定海床土固结过程中的电阻率变化。通过对比分析海床土电阻率与工程力学性质指标的同步测定数据发现:黄河口饱和粉土的电阻率与微型贯入试验测得的土体贯入强度,静力触探试验测得的比贯入阻力,十字板剪切试验测得的不排水抗剪强度(峰值强度、残余强度)均呈乘幂关系,且相关性良好;海床沉积物在固结过程中的电阻率与孔隙水压力呈负线性相关性。 相似文献
12.
Host sediments may exert a significant influence on the formation of gas hydrate reservoirs. However, this issue has been largely neglected in the literature. In this study, we investigated the types, characteristics and the depositional model of the fine-grained gas hydrate-bearing sediments in the northeastern margin of the South China Sea by integrating core visual observations and logging-while-drilling downhole logs. The gas hydrate-bearing sediments consist dominantly of muddy sediments formed in the inter-canyon ridges of the upper continental slope, including hemipelagites, debrites (mud with breccia) and fine-grained turbidites. Cold-seep carbonates and associated slumping talus, muddy breccia debrites, as well as coarse-grained turbidites, may locally occur. Four classes and six sub-classes of log facies were defined by cluster analysis. Core-log correlation indicates that gas hydrates are majorly distributed in fine-grained sediments with high resistivity and low acoustic transit time (AC) log responses, which are easily differentiated from the fine-grained background sediments of high gamma-ray (GR), high AC, and low resistivity log values, and the seep carbonates characterized by low GR, high resistivity, high density, low AC and low porosity log values. The primary host sediments consist of fine-grained hemipelagic sediments formed by deposition from the nepheloid layers of river material and from the microfossils in seawater column. Most of the hemipelagic sediments, however, might have been extensively modified by slumping and associated gravity flow processes and were re-deposited in the forms of debrites and turbidites. Locally developed seep carbonates associated with gas hydrate dissociation and leakage provided additional sources for the gravity flow sediments. 相似文献
13.
Yang Cao 《Marine Georesources & Geotechnology》2013,31(4):477-487
AbstractThe deep-water pipeline is the main means of transportation in offshore oil and gas development engineering. The deep-water pipeline may incur lateral global buckling due to the high temperature and pressure that are applied on the pipeline to ensure the contents’ liquidity. With the increasing operating water depth, a higher temperature and pressure are applied to the pipeline, causing large lateral deformation and a large bending moment. Due to the inhomogeneous distribution of the bending moment on the cross-section, different points on the cross-section will deform differently. This kind of deformation causes the cross-section to turn into an oval ring. The cross-section ovalization caused by global buckling was rarely analyzed in former engineering practice since the load is relatively low. With the increase in operation water depth and operation load, the ovality caused by global buckling is noticeable. This article analyzed cross-section ovalization caused by pipeline lateral global buckling with a numerical simulation method. The pipelines with different initial cross-section shapes were simulated, and the influence of several impact factors, including load, pipeline and soil factors on the ovality of the cross-section, were analyzed. The results show that the initial cross-section shape type has little effect on the pipeline ovalization pattern. The initial ovality of the pipeline with an oval ring cross-section shape has little influence on the residual ovality. Among all the factors analyzed in this paper, the pressure difference is the primary factor that should be considered in a pipeline ovalization check. 相似文献
14.
Guangming Kan Dapeng Zou Baohua Liu Xiangmei Meng Guanbao Li 《Marine Georesources & Geotechnology》2013,31(10):1217-1226
AbstractThree types of sediments were selected to measure their sound speed under changing temperature and pressure conditions in laboratory. The effects of temperature and pressure on sound speed in sediments and their trends were analyzed. The results showed that, with increasing temperature and pressure, the sound speed exhibits an increasing trend in all selected sediments. For each sample, the ratio of the sound speed in sediments to that in seawater almost remained unchanged at different pressures and temperatures, with a maximum fluctuation of 1.09% for temperature dependence and 0.68% pressure dependence. Combining the analysis of experimental results and sound speed correction procedure given by Hamilton, specific correction formulas of sound speed for temperature and pressure were presented. The laboratory-measured sound speed in the experiment and the sound speed obtained in the South Yellow Sea were corrected to reduce the effects of temperature and pressure using the correction formulas. The results show that the correction formulas with constant sound speed ratio are effective for correcting the sound speed measurement errors caused by changes in temperature and pressure. As a further consideration, the effects of the fluctuation of sound speed ratio on sound speed correction were analyzed. 相似文献
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16.
Manganese nodules of the Clarion–Clipperton Fracture Zone (CCFZ) in the NE Pacific Ocean are highly enriched in Ni, Cu, Co, Mo and rare-earth elements, and thus may be the subject of future mining operations. Elucidating the depositional and biogeochemical processes that contribute to nodule formation, as well as the respective redox environment, in both water column and sediment, supports our ability to locate future nodule deposits and to evaluate the potential ecological and environmental effects of future deep-sea mining. For these purposes we studied the local hydrodynamics and pore-water geochemistry with respect to the nodule coverage at four sites in the eastern CCFZ. Furthermore, we carried out selective leaching experiments at these sites in order to assess the potential mobility of Mn in the solid phase, and compared them with the spatial variations in sedimentation rates. We found that the oxygen penetration depth is 180–300 cm at all four sites, while reduction of Mn and NO3− is only significant below the oxygen penetration depth at sites with small or no nodules on the sediment surface. At the site without nodules, potential microbial respiration rates, determined by incubation experiments using 14C-labeled acetate, are slightly higher than at sites with nodules. Leaching experiments showed that surface sediments covered with big or medium-sized nodules are enriched in mobilizable Mn. Our deep oxygen measurements and pore-water data suggest that hydrogenetic and oxic-diagenetic processes control the present-day nodule growth at these sites, since free manganese from deeper sediments is unable to reach the sediment surface. We propose that the observed strong lateral contrasts in nodule size and abundance are sensitive to sedimentation rates, which in turn, are controlled by small-scale variations in seafloor topography and bottom-water current intensity. 相似文献
17.
针对传统海水营养盐检测方法不能满足海水营养盐长期原位监测需求的问题,研制了一种基于分光光度法的多量程海水营养盐原位传感器检测系统,通过对系统的高度集成及对多量程检测、低功耗技术、漏液保护技术的应用,实现了对海水5项营养盐参数快速、宽范围、高精度的原位测量。经过实验室和青岛中苑码头现场测试,表明本营养盐传感器检测系统具有低功耗、高可靠性能,可满足对5项营养盐参数的快速精确测量要求,实现了对海水营养盐参数的原位监测,为相关部门及时了解海洋生态环境和水体富营养化程度提供了数据支持,具有重大现实意义。 相似文献
18.
The recovery of drill cores involves changes in pressure and temperature conditions, which inevitably alter the mechanical properties of unlithified sediments. While expansion from unloading after core recovery is well studied, the effects from cooling on standard geotechnical tests are commonly neglected. Along the central portion of the Nankai margin sediments were recovered from high in-situ temperatures of up to 110 °C during IODP Leg 190. So far, the interpretation of the consolidation state of the Lower Shikoku Basin facies (LSB) entering the accretionary Nankai margin is ambiguous. Results from laboratory consolidation tests at room temperature show high pre-consolidation stresses. These were interpreted as hardening caused by cementation, while the field-based porosity vs. depth trend points towards normal consolidation. As an explanation for this discrepancy, the change of the mechanical properties by cooling from in-situ to laboratory conditions is proposed. In this paper, the results of a thermo-mechanical model are compared to published field data. This comparison suggests that the observed hardening is at least partially an artefact from cooling during core recovery, and that the strata may be considered normally consolidated to slightly overconsolidated. The latter can be explained by minor cementation or the influence of secondary consolidation. The results suggest that cooling from high in-situ temperatures may be important for the interpretation of the consolidation state of other sedimentary successions elsewhere. 相似文献
19.
波浪加载下海底土质特性变化的研究 总被引：3，自引：0，他引：3
通过不同的制样方法 ,在水槽中模拟了多种海底在波浪作用下的变化行为。试验发现 ,加压排水固结的砂质粉土海底在波浪作用下较稳定 ;加压不产生排水而固结的砂质粉土海底易受波浪的冲刷 ;自然条件和轻微振动的砂质粉土海底最易受到波浪的扰动破坏 ,形成塌陷凹坑。粘粒含量较高的粉质粘土对波浪的反映不敏感 ;下卧软土层土体在上覆压力下的变形量与含水量关系密切 ,含水量越高 ,变形越大。试验结果证明 ,波浪会引起沉积物性质发生改变 ,也是引起海底形态变化的主要原因。 相似文献
20.
《Marine Geology》1999,153(1-4):199-219
Pyrite formation within and directly below sapropels in the eastern Mediterranean was governed by the relative rates of sulphide production and Fe liberation and supply to the organic-rich layers. At times of relatively high SO2−4 reduction, sulphide could diffuse downward from the sapropel and formed pyrite in underlying sediments. The sources of Fe for pyrite formation comprised detrital Fe and diagenetically liberated Fe(II) from sapropel-underlying sediments. In organic-rich sapropels, input of Fe from the water column via Fe sulphide formation in the water may have been important as well. Rapid pyrite formation at high saturation levels resulted in the formation of framboidal pyrite within the sapropels, whereas below the sapropels slow euhedral pyrite formation at low saturation levels occurred. δ34S values of pyrite are −33‰ to −50‰. Below the sapropels δ34S is lower than within the sapropels, as a result of increased sulphide re-oxidation at times of relatively high sulphide production and concentration when sulphide could escape from the sediment. The percentage of initially formed sulphide that was re-oxidized was estimated from organic carbon fluxes and burial efficiencies in the sediment. It ranges from 34% to 80%, varying significantly between sapropels. Increased palaeoproductivity as well as enhanced preservation contributed to magnified accumulation of organic matter in sapropels. 相似文献