共查询到20条相似文献，搜索用时 140 毫秒
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鄂尔多斯盆地南部黄土塬区是中国特有的地形地貌,巨厚黄土层弱弹性介质地震激发能量下传问题是地震数据采集的难题。中石化华北分公司经过多年的攻关与试验,对影响黄土塬地震资料品质的主要因素进行了深入分析,形成了一套黄土塬区激发关键技术——选取合理的激发点位、尽可能减少干燥疏松黄土对地震有效信息的吸收与衰减、选择合理的激发药型和激发参数增加子波的能量及拓展子波频带宽度、利用组合效应压制部分侧面干扰等。鄂尔多斯盆地南部黄土塬区三维地震采集关键技术的突破,结束了黄土塬区地震数据采集只能进行沿沟、谷进行二维弯线勘探的历史,使黄土塬区三维地震勘探成为可能。 相似文献
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《物探化探计算技术》2016,(2)
在我国陆地石油勘探中,炸药震源依然是地震勘探的主要震源,炸药爆炸后会产生不同的分区,包括空腔、过渡区和弹性区。如今对地震子波产生机理的分析主要是基于等效球腔模型,忽略了过渡区对波传播特征的影响。为了定性描述过渡区的岩石破碎和永久形变对地震波传播特征的影响,将模型简化为粘弹性介质。这里在Kelvin粘弹性模型基础上推导了地震波传播的相速度和品质因子Q的表达式,并对Kelvin粘弹性模型进行数值模拟,从振幅、相位及频率的角度,分析品质因子Q对地震波传播特征的影响。结果表明,地震波在粘弹性介质中传播时,振幅、频率及相位特征是有变化的,这为研究炸药震源激发产生地震子波的机理提供了理论方向,为实际介质中的地震记录特征分析提供了理论基础,同时对补偿粘滞性因素的影响、提高地震资料的品质具有重要的实际意义。 相似文献
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《物探化探计算技术》2016,(3)
把范氏气体条件下的单枪压力子波模型推广到调谐气枪阵列中,研究了3枪调谐气枪阵列的优化模型及算法,通过数值模拟得出平面阵列作为实验阵列,运用正交优化设计实验得出较好的阵列设计方案,为多枪、多子阵阵列优化设计提供参考。 相似文献
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《中国煤炭地质》2015,(6)
确定地震反演子波以及处理其与各井最优标定子波之间的差异是地震反演与解释所面临的问题之一。以陕北侏罗纪煤田榆横矿区某勘探区为例,对其地震资料采用不同的子波进行标定与反演实验,研究地震子波变化引起的波阻抗数值和结构在纵横向上的变化规律,并讨论其对地质解释的影响。研究表明,在基于模型的反演中,标定和反演所用的地震子波对最终得到的波阻抗具有明显的影响,具体表现在波阻抗幅值、时间轴偏移、纵向变化细节以及横向连续性等。在该区选取子波的研究中还发现,子波变化产生的波阻抗差异逾700(m/s)*(g/cm3),这将导致在密度为2.6 g/cm3的地层中速度误差达300 m/s,其结果必会影响岩性解释的准确性。 相似文献
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水陆过渡带的三维地震勘探方法 总被引：2，自引：0，他引：2
单纯水上和陆地三维地震勘探技术已经非常成熟,对于水陆过渡带条件下的三维地震勘探存在诸多困难。笔者在山东微山湖济宁三号井的三维地震勘探中,地表遍布芦苇、鱼塘、沼泽。条件十分复杂。针对这种情况,在激发和接收中采取了特别技术措施,获得了较好的野外采集资料,在处理中采用地表一致性子波反褶积和地表高程校正,最终地震资料既有较高的信噪比又有较好的分辨率,完成了预定的地质任务,为水陆过渡带三维地震勘探积累了成功经验。 相似文献
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宁夏石槽村井田地震勘探区,地表为风成垄状及新月形流动沙丘．其疏松的沙丘对地震波能量及频率吸收衰减强烈,噪声干扰强,严重降低了资料的信噪比及分辨率,且起伏的沙丘引起的静校正问题也较突出。对此提出了以提高煤层反射波信噪比为主要目的,以提高小断层识别能力为目标的勘探方法．如：高覆盖次数、高频激发、组合检波器面积接收等野外数据采集技术,以及动校正、静校正、子波一致性处理、叠前串联反褶积处理、子波压缩等一系列地震资料处理技术。与原详查成果比较,该区三维地震勘探新发现断层15条,背向斜3个。地震勘探成果表明,针对该沙漠区采取的一系列技术措施,可获得较好的勘探效果。 相似文献
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本文导出了固液两相流体中球空泡的振荡方程,并用数值方法讨论了固体颗粒对它泡运动及泡壁压强的影响,得到了固相浓度、颗粒尺寸等因素与空泡运动之间的定性关系。在分析过程中,考虑了液体与颗粒之间力的双向耦合作用。 相似文献
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Johannes Holocher Frank PeetersWerner Aeschbach-Hertig Markus HoferMatthias Brennwald Wolfgang KinzelbachRolf Kipfer 《Geochimica et cosmochimica acta》2002,66(23):4103-4117
The formation of an excess of dissolved gas (“excess air”) in quasi-saturated media was studied by analyzing and interpreting dissolved noble gas concentrations in laboratory column experiments. Using quartz sand filled columns of 1 m length, two different experimental designs were realized. In the first, groundwater recharge was simulated by a unidirectional vertical water flow through the columns. In the second, groundwater level fluctuations in an aquifer zone without active infiltration were reproduced by cyclic water level fluctuations in the columns. The reproducible generation of excess air under these defined, near natural conditions was successful. Partial or complete dissolution of air bubbles entrapped in the quartz sand could be identified as the mechanism responsible for the generation of excess air. Depending on the experimental design, supersaturation of the dissolved atmospheric noble gases ranging between 1.4% ΔNe and 16.2% ΔNe was found. The measured noble gas patterns were interpreted using inverse modeling and conceptual gas exchange models and were compared to results of numerical simulations of gas bubble dissolution in water filled soil columns. The gas composition in most of the samples resembles either unfractionated pure atmospheric excess air or is fractionated in accordance with closed-system equilibration between entrapped air and surrounding water. In addition to the amount of entrapped air, the hydrostatic pressure exerted on the entrapped air bubbles is the dominating parameter responsible for the total amount of dissolved air. The composition of the excess air component is controlled by the water flow regime, the bubble size distribution, the initially dissolved gas concentrations and the initially entrapped gas composition. 相似文献
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揭示煤层气排采储层非饱和流阶段煤粉与气体相互作用机理,对制定排采制度和提高产气量具有重要意义。通过气泡–煤粉微观作用实验装置,系统开展了不同直径大小的气泡对不同粒度和密度煤粉的作用实验,分析了气泡对煤粉运移轨迹和速度的影响及捕获煤粉特征。结果表明,气泡产出能够影响煤粉的运移轨迹,甚至能够捕获煤粉;煤粉通过气泡时会产生3种运动类型：沿着气泡表面运移到气泡底部最后被捕获、沿着气泡表面运移到气泡底部最后脱落及接近气泡时被排斥而轨迹发生偏转。煤粉若被气泡捕捉,则运动速度呈现出减小–增大–减小的变化特征;若未被气泡捕获,速度呈现出减小–增大–减小–增大的变化特征。不同条件下气泡对煤粉的捕获效率高达64.38%～86.64%;在气泡表面最高点附近发生碰撞煤粉被捕获的概率最大,并且随着偏离角度的增大,气泡捕获效率均呈现出逐渐减小的趋势;在相同的碰撞位置下,气泡对煤粉的捕获效率随着煤粉密度、煤粉粒径的增大而减小,随着气泡直径的增大而增大。煤层气产气初期应根据储层的实际导流能力合理控制降压速率,若储层导流能力较强,应加大排采速率,增大气体解吸对煤粉的扰动和捕获作用,促使大量煤粉随地下水或气泡产出;若储层... 相似文献
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静水生长的淡水湖冰微结构的季节变化及其受生长过程的影响 总被引：3，自引：2，他引：1
冰物理微结构特征控制着冰层基本物理性质。基于多年冬季对东北平原区水库和湖泊冰层生消过程、气象条件,以及冰层晶体、冰内气泡和密度特征的现场观测,分析了淡水湖冰微结构的季节演化和年变化规律及其影响因素。湖冰晶体结构、气泡含量与分布、冰密度具有明显的分层结构,且在冰厚增长期和稳定期内基本维持不变;进入融化期,冰内微结构变化迅速,表现为晶体边界融化、气泡体积扩展和融水迁移。不同年份、不同湖泊冰晶体类型和气泡形态类似,但各类晶体层厚度比例、气泡含量与尺寸存在差异。统计分析显示,晶体和气泡结构与湖冰生长速率关系密切,晶体粒径与生长速率呈正比,水内气体的产生和溶解过程、水体扰动程度的差异影响着气泡含量同生长速率之间的关系。 相似文献
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根据溶解气体的传输过程,对大坝泄洪导致下游水体溶解气体浓度超饱和现象进行了理论分析.引入溶解气体的有效饱和浓度、气泡被卷吸进入水体的有效水深等参数,认为下游水体中溶解气体的来源不仅依赖于大气在自由水表面的传质,而更多地依赖于气体在气泡界面的传质.把难以测量的气体传质系数、气泡尺寸等参数与水流的紊动特性参数建立定量关系,以美国Ice Harbor大坝为例,采用该定量关系式计算了下游水体中溶解气体浓度的分布,实测结果验证了理论分析的合理可靠性. 相似文献
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A.R. Laplante J.M. Toguri H.W. Smith 《International Journal of Mineral Processing》1983,11(3):203-219
Bubble size distributions and flotation rates were determined as a function of air flow rate and frother concentration using a specially designed batch flotation cell. This cell permitted the unambiguous determination of the flotation rate from the slurry to the froth.Flotation rate constants were determined for different size classes of silica and galena. The flotation rate constants increased to a maximum and then decreased as air flow rate was increased. This maximum was predicted by a model which considered the effect of bubble size on both the total bubble surface area and the bubble-particle collision efficiency. This work shows that collision efficiency effects, shown to exist in single-bubble/single-particle systems, are also present in flotation systems where many bubbles and particles interact.A second model for hindered flotation is proposed which assumes that the particle-capturing bubble surface differs from the particle-retaining surface. This model predicts a sharp transition from hindered to free flotation. Experimental results are presented which agree well with those derived from the model. 相似文献
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《International Journal of Mineral Processing》2005,75(1-2):69-82
A phenomenological model is developed to describe the induction time of an air bubble in contact with a hydrophobic sphere, based on an analytical solution of Reynolds approximation under the specific boundary conditions. A modified version of induction time apparatus is used to measure the induction time of an air bubble with a methylated silica bead, an untreated silica bead in dodecylamine solutions and a bitumen droplet in alkaline solutions. It was found that the induction time between an air bubble and a silica bead (or a bitumen droplet) increased with increasing bubble size. The bubble size dependence is stronger for the large silica beads (or bitumen droplets) tested. The induction time, obtained from two different methylated silica beads diameters, is used to estimate the average net driving force (F̄o) for the intervening liquid film drainage and rupture and the critical film thickness (hc) in the established model. Through curve fitting, the values for F̄o and hc are found to be 3.5×10−8 N and 150 nm, respectively, for a methylated silica–bubble system. The predicted values of critical film thickness and the net driving force for the systems used in this study are in excellent agreement with those reported in the literature, confirming the present theoretical analysis and model development. The suitability of using the liquid drainage time to represent the induction time, or the attachment time, is experimentally justified. 相似文献
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Modelling Rock Blasting Considering Explosion Gas Penetration Using Discontinuous Deformation Analysis 总被引：1，自引：0，他引：1
Explosion gas plays an important role in rock mass fragmentation and cast in rock blasting. In this technical note, the discontinuous deformation analysis method is extended for bench rock blasting by coupling the rock mass failure process and the penetration effect of the explosion gas based on a generalized artificial joint concept to model rock mass fracturing. By tracking the blast chamber evolution dynamically, instant explosion gas pressure is derived from the blast chamber volume using a simple polytropic gas pressure equation of state and loaded on the blast chamber wall. A bench blasting example is carried out. The blast chamber volume and pressure time histories are obtained. The rock failure and movement process in bench rock blasting is reproduced and analysed. 相似文献
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Single bubble velocity profile (velocity vs. distance) has been measured for a 1.45 mm diameter bubble to try to explain reported differences in gas holdup in two systems: F150 vs. 1-pentanol, and MIBC vs. NaCl. It was found that in F150 the bubble slowed rapidly to reach the terminal velocity stage of the profile while in 1-pentanol the bubble remained in the deceleration stage and was consequently moving faster, at almost twice the speed. The lower rise velocity in F150 means longer bubble residence time and corresponding higher gas holdup than with 1-pentanol, as reported. In the second system, the bubble in MIBC reached terminal velocity more rapidly than in NaCl which agrees with the reported higher gas holdup in MIBC compared to NaCl. An implication for gas holdup evaluation is that the value may depend on the part of the velocity profile over which it is measured. Possible exploitation of this reagent effect on bubble rise velocity in flotation is considered. 相似文献
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在原有有限元/离散元（FEM/DEM）耦合分析方法中,实现了一种新的爆破计算模型。该模型考虑了在爆生气体的作用下,随着裂隙的扩展,气体占据的体积不断增大,气体压力逐渐减小这一问题。同时考虑了气体嵌入与爆腔联通的裂隙对裂隙的作用力。克服了原有FEM/DEM方法中的爆破模型仅仅将压力施加于爆腔四周的岩壁上,无法考虑爆生气体嵌入生成的裂隙对裂隙的作用。提出了一种新颖的贯通裂隙网络形成的递归搜索算法,只需通过编写一个简单的递归函数,即可实现复杂裂隙网络的搜索,采用一种简洁的方法完成了对复杂问题的处理。最后通过一个爆破算例,结果表明FEM/DEM方法可以对爆炸过程中应力波的传播及岩体中裂纹的萌生、扩展进行全程捕捉,展现了该方法用于爆破模拟的潜力。 相似文献