川西拗陷须五段非常规气形成条件分析

随着对非常规气蔵的研究方法和开采手段的升级,使页岩气得以开发。川西拗陷须五段常规的思维是把它作为烃源岩来认识的,运用非常规页岩气的研究理念和方法,针对川西拗陷两条野外剖面(莲花剖面、万家坪剖面)及6口取心井(XYHF-1井,XYHF-2井,X503井,FG5井,GH2井,MY1井)的岩心观察、取样分析测试,以分析川西拗陷须五段具有形成非常规气蔵的条件,并用3种不同的表征方法(激光共聚焦法、高压压汞法、氮气吸附法)对须五段内不同类型的岩石进行孔隙度、渗透率及其连通性时行表征,结果表明:细砂岩中不同类型孔隙的孔隙度为0.41%～6.65%,平均总孔隙度为2.14%;泥(页)岩的孔隙度为1.51%～5.99%,总孔隙度为2.70%。微米CT扫描发现须五段上亚段细砂岩的连通性好于下亚段,中亚段以粉砂岩为主,孔隙连通性差,有机质含量低;泥(页)岩的孔隙连通性也差,孔隙发育依附于有机质的发育,泥(页)岩样品的有机碳含量主要分布在0.5%～3%之间。综合评价认为马井-邡、崇州-郫县、新场-丰谷等地区成蔵条件较好,为I类地区,是川西坳陷须五段页岩气的目标区域。     

Stiff soil amplification effects in the 7 September 1999 Athens (Greece) earthquake

The Athens, Greece, earthquake of 7 September 1999 provided a number of reliable strong motion recordings and well-defined patterns of damage at sites with known geological and geotechnical conditions. Joint evaluation of this evidence shows that the very stiff soils of the Athens basin, compared to the nearby outcropping soft rocks, have amplified the peak horizontal acceleration by an average of 40% or more and have shifted elastic response spectra to higher periods. US and the European seismic code provisions (NEHRP-97 and EC-8), place stiff soils and soft rocks at the same site category and consequently fail to predict these adverse effects. A larger number of site categories and new site coefficients that depend on the seismic excitation frequency appear necessary in order to overcome this deficit of the codes.     

地震多属性综合解释的支持向量机方法研究

能够同时对多种属性进行训练,具有优秀推广能力的支持向量机(Support Vector Machine,简称SVM)方法是进行高精度地震参数预测的有力保障。然而,支持向量机中用于构建回归估计函数的参数最优解很难确定。针对该问题,通过建立数学模型进行参数选择研究,总结出了参数ε、C、σ2对样本预测的影响规律。在此基础上提出了求取惩罚因子C和核参数σ2的权系数公式。结合提出的参数求取公式,利用支持向量机方法,以地震属性为输入向量对渤海SZ36-1油田的砂泥岩百分比和孔隙度进行了预测。结果表明,利用该方法对储层参数进行预测具有较高的预测精度;权系数公式的提出极大地缩短了构建回归估计函数所耗用的时间,简化了参数选取的难度。     

鄂尔多斯盆地陕北地区长101高渗储层的控制因素

鄂尔多斯盆地中部的陕北地区,是盆地中生界油藏最为丰富的区带之一,主要含油层系为三叠系延长组长6层,其次是侏罗系延安组,以往的研究也多集中于以上含油层。长101层是近几年勘探评价的新层系,利用现代测试技术和数理统计研究了长101层的沉积、成岩特征,分析高渗储层控制因素。结果表明,沉积环境控制长101高渗储层分布,成岩作用对长101高渗储层的形成起主导作用。主河道砂岩厚度大、粒度粗、孔喉大、孔隙连通性好,河道侧翼砂岩厚度薄、粒度细、孔喉小、孔隙连通性差。因此,压实作用后主河道砂岩粒间孔含量多于河道侧翼砂岩,导致主河道砂岩胶结作用弱于河道侧翼砂岩,而溶蚀作用强于河道侧翼砂岩,主河道砂岩物性明显好于河道侧翼。沉积、成岩作用共同造成长101高渗储层发育于河道主带和分流交汇部位。     

基于原子力显微镜表征的含油储层微观孔隙结构分析及应用

为研究岩心微观孔隙结构在强碱三元复合驱替过程中的变化特征,以大庆油田南5-4-检725井855.0m处岩心为对象,通过原子力显微镜观察岩心形貌特征,定量分析孔喉宽度和深度;分析驱替过程中岩心样品的面孔率、孔喉宽度和深度、分形维数等参数变化反映的微观孔隙结构变化规律.结果表明:原子力显微镜获得的图像可以真实反映储层岩石微观形貌特征,储层微观孔隙结构具有二段式分形特点.微观孔隙结构变化特征在驱替初期,主要表现为岩石粒间颗粒运移;在驱替中后期,主要表现为强碱三元驱替剂与岩石相互作用,生成驱替剂残留或其他产物.该研究结果对分析强碱三元复合驱替后剩余油分布规律、制定后续开发方案具有指导意义.     

Geotechnical properties of the Cassino Beach mud

Knowledge of the marine soils properties, together with hydrodynamic and climatic data, plays an important role for a better understanding of the dynamic behavior of sandy and muddy coasts. This paper deals with reporting and basic interpretation of two campaigns of exploration and characterization of the mud of Cassino Beach, southern Brazil, carried out during the years of 2004 and 2005. Samples were obtained by means of cores collected at some locations offshore, and were submitted to various laboratory geotechnical tests, including determination of the physical index, grain size distribution, Atterberg limits, and shear resistance by both triaxial and shear vane tests. Results confirm the existence of a very soft soil deposit offshore Cassino Beach, highly plastic, compressible, and viscous, forming an important database for further studies.     

A new method to characterize the spatial structure of soil macropore networks in effects of cultivation using computed tomography

Soil macropore networks are subsurface connected void spaces caused by processes such as fracture of soils, micro‐erosion and fauna burrows. Axial X‐ray computed tomography (CT) scanning provides a convenient means of recording the spatial structure of soil macropore networks. The objective of this study were to (1) based on CT technique and GIS digitized image method, construction a new technique for tracing, visualizing and measuring the soil macropore networks and (2) investigate the effects of farming activities on soil macropore networks characteristics. Our technique uses left‐turning and nine‐direction judgment methods, a combination of the layer‐by‐layer analysis method and the up‐down tracking algorithm. The characteristics for the overall structure patterns of macropores, the spatial distribution of the macropore networks and each single macropore network can be conveniently identified by our technique. Eight undisturbed soil columns from fields with two distinct land uses (under cultivation and not been cultivated) and four different depths (0–20, 20–40, 40–60 and 60–80 cm) were investigated. The soil columns were scanned using X‐ray CT at a voxel resolution of 0.075 × 0.075 × 3.000 mm. Results indicate that farming activities can destroy the initial structure of macropores, and those remaining are mainly small‐sized and medium‐sized networks with lower extension and hydraulic conductivity. The network properties show a significant difference between upper and lower layer. The results can provide beneficial reference to further research centered on non‐equilibrium flow prediction and chemical transport modeling in field soils. Copyright © 2013 John Wiley & Sons, Ltd.     

Environmental assessment and nano-mineralogical characterization of coal,overburden and sediment from Indian coal mining acid drainage

The deterioration of environmental conditions is the major contributory factor to poor health and quality of life that hinders sustainable development in any region.Coal mining is one of the major industries that contribute to the economy of a country but it also impacts the environment.The chemical parameters of the coal,overburden,soil and sediments along with the coal mine drainage(CMD)were investigated in order to understand the overall environmental impact from high sulphur coal mining at northeastern coalfield(India).It was found that the total sulphur content of the coal is noticeably high compared to the overburden(OB)and soil.The volatile matter of the coal is sufficiently high against the high ash content of the soil and overburden.The water samples have a High Electrical Conductivity(EC)and high Total Dissolve Solid(TDS).Lower values of pH,indicate the dissolution of minerals present in the coal as well as other minerals in the mine rejects/overburden.The chemical and nano-mineralogical composition of coal,soil and overburden samples was studied using a High Resolution-Transmission Electron Microscopy(HR-TEM),Energy Dispersive Spectroscopy(EDS),Selected-Area Diffraction(SAED),Field Emission-Scanning Electron Microscopy(FE-SEM)/EDS,X-ray diffraction(XRD),Fourier Transform Infrared Spectroscopy(FTIR),Raman and Ion-Chromatographic analysis,and Mossbauer spectroscopy.From different geochemical analysis it has been found that the mine water sample from Ledo colliery has the lowest pH value of 3.30,Tirap colliery samples have the highest electrical conductivity value of5.40 ms cm~(-1)Both Ledo and Tirap coals have total sulphur contents within the range 3-3.50%.The coal mine water from Tirap colliery(TW-15 B)has high values of Mg~(2+)(450 ppm),and Br~-(227.17 ppm).XRD analysis revealed the presence of minerals including quartz and hematite in the coals.Mineral analysis of coal mine overburden(OB)indicates the presence both of pyrite and marcasite which was also confirmed in XRD and Mossbauer spectral analysis.The presented data of the minerals and ultra/nano-particles present shows their ability to control the mobility of hazardous elements,suggesting possible use in environmental management technology,including restoration of the delicate Indian coal mine areas.     

(T2,D)二维核磁共振测井识别储层流体的方法

当地层孔隙中油气和水同时存在时,在核磁共振T2分布上不同流体信号往往重叠,很难有效识别.本文采用改变回波间隔测量多组自旋回波串序列实现了（T2,D）二维核磁共振方法,为有效识别储层流体提供了基础.通过数值模拟系统研究了（T2,D）方法在不同储层、不同测量信噪比以及不同外加磁场梯度条件下识别流体的效果.结果表明：（T2,D）方法识别中、低黏度油层具有优势,随着信噪比增加和外加磁场梯度加大,分辨油和水的效果将变好.在气层,对磁场梯度有一定要求,并且,测量数据的信噪比越高,分辨气与水的效果越好,当测量数据信噪比低于70时（T2,D）方法在气层可能失效.在2MHz共振频率下,利用MARAN核磁共振岩芯分析仪器,对含顺磁性物质的饱和流体岩样进行了实验测量,验证了（T2,D）方法的有效性.