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121.
Exploitation of coalbed methane (CBM) is directly affected by the strike and density of fractures, particularly because fractures can act as conduits for water and gas (after desorption). To realize the azimuthal amplitude versus angle (AVA) inversion for a CBM reservoir, we treated reservoirs whose fractures are aligned vertically as being equivalent to a horizontal transverse isotropic medium and simplified the P-P wave reflection coefficient formula to an approximately linear equation. Then, we adopted a modified damping least squares algorithm to solve the azimuthal AVA inversion problem. With edited macro-bins, corrected residual moveout, and normalized amplitude, the azimuthal gathers exhibited unambiguous azimuthal AVA characteristics. The #3 CBM reservoir in the Qinshui Basin was selected for a case study. The density and strike of the reservoir fractures were obtained and analyzed, and the reservoir was divided into three classes according to fracture density. Finally, in comparison with the gas production data, we confirmed that the inversion results and reservoir classification were both reasonable and credible. 相似文献
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This paper proposes a new method using centroid sliding pyramid (CSP) to identify the removability and stability of fractured hard rock in tunnel and slope engineering. The new method features two geometrical and topological improvements over the original key block method (KBM). Firstly, all the concave corners are considered as starting points of cutting process when a concave block is divided into a set of convex blocks in the original KBM. Only the concave corners formed by two joint planes are used for partitioning a concave block in the presented method and concave corners with free planes are excluded. Secondly, joint pyramid for removability computation in the original KBM is generated using all of the joint planes, while CSP is calculated only from the joint planes adjoining the free planes. The cone angle θ of CSP is the vectorial angle formed by the two candidate sliding surfaces of this CSP. Removability analysis of a block is transformed into calculating the cone angle of CSP. The geometrical relationship is simplified, and data size for removability computation is reduced compared with the original KBM. The provided method is implemented in a computer program and validated by examples of fractured rock slopes and tunnels. 相似文献
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锆铝基柱撑蒙脱土的制备研究 总被引:1,自引:0,他引:1
以钠基蒙脱土为原料,采用共聚法合成锆铝基柱撑蒙脱土,并研究不同锆铝摩尔比例和不同NaOH的量对柱撑蒙脱土制备的影响。XRD研究表明,当锆铝摩尔比例为1:6、加入70ml0.4mol/LNaOH时,可得到(001)面网层间距达1.9343nm的锆铝基柱撑蒙脱土。通过FT—IR发现,锆铝聚合羟基阳离子进入蒙脱土层间,形成Si-O-Al和Si-O-Zr。对柱撑前后蒙脱土的比表面积和孔径结构进行分析,发现锆铝基柱撑蒙脱土具有较大的比表面积,较为均匀的孔径分布,是一种合适的催化和吸附材料。 相似文献
125.
SEED格式STEIM2数据压缩算法在实时地震数据传输中的应用 总被引:9,自引:1,他引:8
在一定带宽内,及时、高效、无失真地传输地震数据是地震数据传输的基本要求,SEED格式给出的数据格式在数据压缩方面有其独到之处,但SEED格式没有定义数据正确性和完整性保证机制和检验方法,因而影响实时传输中的使用。本文提出一种基于SEED格式的STEIM2数据压缩算法,同EDAS数据包形式兼容的实时压缩数据包编码方法,来实现实时压缩数据的传输。经理论评估和实际数据检验,它容易实现,效率高,安全,可靠,完全可以应用于实时数据传输。 相似文献
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In this paper,the quantitative relationship between the wild fruit communities and direct environmental factors is discussed on the basis of detailed data on landscape scale habitats obtained through field vegetation investigation.The results from TWINSPAN and DCCA showed that:1) In the distribution sections of the wild fruit forest in the Keguqin Mountain region,the basic patterns characteristic of the different habitats are due to topographic factors,nutrients and moisture conditions;2) The elevation affected the most basic differentiation of plant communities in the study area,indicating that the elevation condition was the most important factor restricting the distribution of the wild fruit communities in the study area;3) The close relationship between the moisture content in the upper soil layer and the elevation reflected the influence of moisture conditions on both wild fruit and herb-layer communities;4) Nutrient differences not only indicated that the habitat conditions were different in themselves but also showed that the present nutrient conditions of the habitats were seriously affected by human activities.In summary,under complicated mountainous topographic conditions,the habitat conditions for the communities differed very significantly,and the combination of elevation,soil moisture content,total nitrogen,slope aspect,and pH value influenced and controlled the formation of community distribution patterns in the study area. 相似文献