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851.
本次研究采用断面正应力大小、泥岩削刮比(SGR)、断裂带充填物泥质含量(Rm)和断面紧闭指数等定量参数,对车拐地区红车断裂封闭性进行了详细评价。结果显示泥岩削刮比(SGR)均值为0.6,断裂带充填物泥质含量(Rm)均值为0.51,泥质充填程度较高,断面正应力大小变化不大,为69.54~73.11MPa,整体较大,紧闭指数为1.28~8.25,均值为3.98。从而认为准噶尔盆地车拐地区红车断裂带二叠系及三叠系封闭性较好,侏罗系封闭性差。红车断裂带中部、北部断层封闭性较好,而发育于浅部乌尔禾组、三工河组内的小断层在现今及油气成藏期的封闭性也普遍较好。 相似文献
852.
Ancient lacustrine storm-deposits that act as petroleum reservoirs are seldom reported. The Lijin Sag, which is located in the southeastern corner of the Bohai Bay Basin in East China, is a NE–SW trending Cenozoic half-graben basin. Some of its Eocene deposits (Bindong deposits) were interpreted as lacustrine tempestites. The Bindong tempestites, which developed in the lower part of the upper fourth member of the Shahejie Formation (Es41), constitute a new kind of petroleum reservoir and are novel petroleum exploration targets in the Bindong Area. However, the characteristics of the Es41 Bindong tempestite reservoirs and their controlling factors are poorly understood. Point-count analyses of thin sections, scanning electron microscope image analyses, X-ray diffractometry data, and the petrophysical parameters of the Bindong tempestite reservoirs were utilized to estimate the reservoir quality. The reservoirs have undergone significant diagenetic alteration, which can be divided into negative and positive aspects. The negative alteration includes compaction, authigenic minerals, and cementation such as carbonates, clay minerals and overgrowths of quartz and feldspar. The uneven distribution of carbonate cement increased the reservoir’s heterogeneity, with carbonate cement commonly precipitating along the sandstone-mudstone contacts. The primary porosity was severely reduced because of compaction and extensive carbonate cementation. Positive alteration includes dissolution, carbonate cementation, undercompaction and fractures. Carbonate cementation exhibited both positive and negative effects on the reservoir quality. Overall, the objective reservoir quality is quite poor. A quantitative evaluation of the reservoirs’ potential was conducted. The cutoff values of several of the reservoir’s parameters were calculated. The lower limits of the porosity and permeability are 8.35–5.85% and 1.2587–0.2753 × 10–3 μm2, respectively, depending on the depth. The upper limits of the carbonate and mud content are approximately 18.5% and 9–10%, respectively. A fundamental understanding of these characteristics will provide necessary information for extracting hydrocarbons from analogous subsurface reservoirs. 相似文献
853.
854.
《海洋技术学报》2023,(4)
浮标锚链因磨损而断裂会导致浮标丢失,所以针对浮标锚泊系统的研究对锚链设计具有重要意义。为解决锚链系泊力计算方法精度不足和锚链力学简化模型与锚链实际形态不一致的问题,通过VOF (Volume of Fluid) 界面捕捉法建立了三维风、浪耦合流场,基于流体力学计算软件STAR-CCM+对一种滚塑浮标及锚链进行数值仿真计算。在建立双链节锚链物理模型基础上,通过求解浮标在风、浪中的受力及浮标与锚链连接处的受力损失求取锚链系泊力。结果显示,风浪越大,锚链的系泊力损失越大,2、3、4 级海况下浮标阻力损失分别为17.1%、36.6%、55.8%。锚链的双链节受力并非均等,主受力链节在2、3 级海况时承担90%以上的锚链系泊力,次受力链节的系泊力随着总系泊力的增加而增加,可见双链节锚链规格应与单链节相同。 相似文献
855.
Flexible segment model (FSM) is adopted for the dynamics calculation of marine cable being laid. In FSM, the cable is divided into a number of flexible segments, and nonlinear governing equations are listed according to the moment equilibriums of the segments. Linearization iteration scheme is employed to obtain the numerical solution for the governing equations. For the cable being laid, the payout rate is calculated from the velocities of all segments. The numerical results are shown of the dynamic motion and tension of marine cables being laid during velocity change of the mother vessels. 相似文献
856.
Maoxin Su Peng Wang Daohong Qiu Zhiqiang Li Teng Xia 《Marine Georesources & Geotechnology》2013,31(9):1119-1129
AbstractCollapse is a major threat in tunnel construction. How to predict collapse risk accurately and timely is a complicated problem. In this paper, a non-linear mathematical model is applied to obtain the potential risk indices for a submarine tunnel using statistical analysis based on previous submarine tunnels, such as the Seikan tunnel and Xiang’an tunnel. Rough set theory is used to screen risk indices, determine each indicator value, and classify risk factors. Traditional weight calculation methods that are overly dependent on expert experience and other subjective factors are optimized and improved. Based on the frequency of each risk factor, the objective weight value of each risk index is determined according to weight back analysis theory. The ideal point method is used to calculate the collapse risk level. Predictions made by this new method are consistent with the actual tunnel collapse risk levels. This new method provides theoretical and technical basis for effectively predicting tunnel collapse. 相似文献
857.
858.
提出一种直接基于八向链码的矩的快速计算方法,给出了与多边形近似法矩的计算及形状识别时间比较,最后使用不变性矩和人工神经网络完成2—D形状识别。实验结果表明,本文所提出的方法具有更高的计算和识别速度。 相似文献
859.
利用第一性原理计算硝酸根与1~3个水分子形成的水合物(NO3-.nH2O,n=1~3)的红外吸收谱,并与测量的硝酸钠水溶液的红外吸收谱进行了比较分析。计算结果表明硝酸根与水分子所形成的水合物具有多种稳定的结构,其中硝酸根与1个水分子结合的亚稳定结构,其硝酸根反对称伸缩振动的劈裂与硝酸钠水溶液中硝酸根的红外吸收谱结果一致,表明硝酸盐溶液中每一硝酸根与附近水分子的作用效果等效为NO3-.1H2O。 相似文献
860.
在对预应力设计基本要求及布束原则、预应力设计的理论依据及预应力筋布置形式分析的基础上,对大跨径预应力混凝土连续刚构桥的预应力钢束配置进行了研究,通过已建连续刚构桥得出预应力钢束的用量,并通过有限元程序对所得数据进行验证分析,得出了一些规律和结论,可以作为同类桥梁的设计参考. 相似文献