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991.
Thirteen coal areas of the Maritime Provinces in Atlantic Canada are estimated to contain some 2.23 trillion m3 (78.8 TCF) [TCF, BCF, MCF: trillion, billion, million cubic feet]) of coalbed methane resources. This compares with 510 billion m3 (18 TCF) of natural gas calculated for the Sable offshore resources in eastern Canada. In the United States, where coalbed methane resource evaluations and production have increased substantially over the past 20 years, 7% (1.34 TCF) of total domestic gas production is derived from coalbed methane. In this period, the cumulative US production of coalbed methane has exceeded 198 billion m3 (7 TCF) and more than 8000 coalbed methane wells have been drilled.In Maritime Canada, the largest coalbed methane resources occur in the offshore areas of the Gulf of St. Lawrence and Sydney Basins where 196 and 26 billion m3 (69 and 9.3 TCF) of gas, respectively, have been projected. In the old mines, the greatest resources are present in the Prince and Phalen mines of the Sydney coalfield, which together contain 1.70 billion m3 (60 BCF) of gas, and in the Westville mine of the Pictou coalfield with 198 million m3 (70 BCF).Vitrinite is the dominant constituent in 27 of the 42 coals examined. Vitrinite/inertinite ratios for these 27 coals range from 4.0 to 8.4. These high values may indicate the presence of highly fractured coals with corresponding high permeability and flow efficiency, favourable for the storage and flow of methane gas. Coal rank has a pronounced effect on coalbed methane generation, and the prime gas zone often lies between 1.2% and 1.6% Ro max. (medium to low volatile bituminous). The prime zone in the Maritimes Basin underlies much of the central and eastern Gulf of St. Lawrence, and extends for significant distances seaward into the offshore Sydney Basin.Coalbed methane production from the very large resources available in Atlantic Canada may provide a valuable and long-lasting energy resource, largely free of polluting components. 相似文献
992.
地形指数的物理意义分析 总被引:34,自引:4,他引:34
地形指数模型 ( TOPMODEL)用地形指数在流域中的空间格局来确定流域饱和缺水量的空间分布和产流区的空间位置与范围 ,物理意义明确。本文介绍了地形指数的物理基础及其与土壤水分的关系。分析了地形指数空间变化与汇流面积 a及局地坡度空间变化的关系 ,a范围内有效汇流面积的变化 ,提出了一种确定 a上限值的方法。 相似文献
993.
Suspended sediment transport effectiveness was examined near the mouths of three large impounded rivers (Rio Grande, Brazos,
and Pearl Rivers) in differing precipitation regimes in the U.S. Gulf Coastal Plain. Magnitude and frequency analysis of suspended
sediment transport was performed by examining the effectiveness of both discharge and time in transporting suspended sediment.
Bivariate plots of discharge with infrequent values of silt/clay and sand provide an insight into the relative proportion
of coarse-versus fine-grained sediment transport for the three rivers. Despite the aridity of the Rio Grande and Brazos drainage
basins, which is often associated with infrequent or episodic transport of sediment, the duration of the effective discharge
is similar to humid basins described in the literature. The majority of sediment transport occurs during the moderate discharge
events, having a duration of 2.4%, 1.5%, and 4.4% for the Rio Grande, Brazos, and Pearl Rivers, respectively. This may be
due to the influence of scale or the influence of upstream dams and reservoirs on discharge and sediment transport. Findings
from this research suggest that magnitude and frequency analysis of discharge and suspended sediment near the mouths of large
rivers may provide a useful framework for understanding the timing and delivery of riverine sediments to the nearshore coastal
environment from rivers draining a range of geologic and climatic settings.
Received: 6 September 1996 · Accepted: 4 February 1997 相似文献
994.
柴达木盆地跃进地区E31、N1、N21碎屑岩储层特征 总被引:5,自引:0,他引:5
通过 15口井近百个铸体片的鉴定及压汞数据的分析,对跃进地区E31、N1、N21碎屑岩储层取得如下认识 :①长石砂岩、岩屑长石砂岩、长石岩屑砂岩为主,成分成熟度和结构成熟度均较低;②储层经历压实压溶作用、成岩自生矿物胶结和溶解作用,剩余原生粒间孔占绝对优势,相同层位地层在跃东和跃西因埋藏深度不同导致成岩-孔隙演化史也不同,西区储层物性明显优于东区;③储层主要发育于水上分流河道、砂坪和辫状河道微相,碎屑的成份和结构成熟度、填隙物含量、成岩环境对储层性质有重要影响;④西区E31储层属高孔中渗的Ⅱ类储层,大孔细喉道组合特征,储集物性较佳,东区E31储层属特低孔特低渗的Ⅴ类储层,中孔微细喉道组合特征,储层物性不理想,N1储层属低孔特低渗的Ⅳ-Ⅴ类储层,大孔小喉道组合特征,渗透率不佳. 相似文献
995.
塔里木盆地库车坳陷白垩系辫状三角洲砂体成岩作用和储层特征 总被引:40,自引:8,他引:40
通过对库车坳陷白垩系辫状三角洲的研究,总结辫状三角洲的沉积特征是:1.由于辫状河流直入湖泊,沉积物比较粗,中砂岩和细砂岩占有相当的比例,可达 6 0 %~ 80 %,最高达 95 %。 2.成分和结构成熟度低-中等,一般为长石砂岩、岩屑长石砂岩和岩屑砂岩,石英含量 30 %~ 5 0 %,岩屑含量可高达 5 0 %以上,一般为 30 %左右,岩屑成分复杂。3.沉积构造以块状层理、大型槽状交错层理和斜层理为主,见平行层理、波状层理和极少量的水平层理。4.辫状河道的主要沉积期是洪水期,因而河道具快速迁移性,沉积作用具有阶段性,砂体之间多次重复叠加,在滨岸地区辫状砂体性质相似而垂向侧向连接,成为分布面积很大的砂体,砂层之间只有薄层的泥质夹层。对研究区露头和岩心的普通薄片、铸体薄片、阴极发光及扫描电镜等资料的分析研究,认为该区成岩作用包括压实、胶结、溶蚀、交代、压溶和重结晶等作用,并且以前三类为主。根据对自生矿物、粘土矿物、I/S间层中的S %、包裹体测温、成岩作用类型及特点等分析,判断研究区白垩系成岩阶段已达晚成岩A期。白垩系砂岩储层特殊的沉积-成岩水介质条件、构造-埋藏演化史、异常高压背景等决定了其特有的成岩序列演化的特点。白垩系巴什基奇克组上部和底部、巴西盖组砂 相似文献
996.
I. M. Artemieva 《Surveys in Geophysics》1996,17(3):289-306
Fluids saturating cracked rocks within the crust can vary widely in composition and physical properties, which depend greatly on pressure and temperature. External non-hydrostatic stress applied to a cracked medium may result in a significant change of crack volume (and hence, for the undrained regime, pore-fluid pressure) due to the processes of crack closure (opening), and thus lead to a drastic change of the overall physical parameters of a rock. The purpose of the study is to estimate theoretically, using the effective-medium theory, the macroscopic seismic and transport parameters (such as permeability) of cracked rocks (granites) saturated with hydrocarbon gases, oils, brines and water. Variations of crack geometry and fluid parameters in the closed system (at constant fluid mass) under uniaxial compression are considered as well. The results show that composition of a saturating fluid as well as fluid temperature greatly influence the effective permeability and shear velocities of a rock mass, while thermal conductivity is not so sensitive to variations of fluid parameters. 相似文献
997.
998.
四川资阳及邻区灯影组古岩溶特征与储集空间 总被引:8,自引:1,他引:8
本文通过对资阳地区灯影组钻井岩心的宏观、微观及地球化学特征的研究发现,灯影组曾受到多期不同程度岩溶作用的改造,形成了一系列特征的岩溶标志。根据岩溶期次及与储集空间发育的关系等进一步将岩溶划分为同生-准同生期、表生期、中-深埋藏期、褶皱期四种岩溶类型。现今灯影组天然气的储集空间主要受到岩溶作用的控制,是多期岩溶作用长期叠加的结果。 相似文献
999.
岩体系统渗流场与应力场耦合的广义双重介质模型的应用研究 总被引:11,自引:1,他引:11
本文通过实验资料分析, 提出了裂隙岩体应力与渗流之间的分形几何关系式。以研究区岩体系统结构为基础, 提出了岩体系统应力场与渗流场耦合的广义双重介质模型, 并将该模型应用于某水利水电工程的渗流与控制中, 对坝区岩体进行了应力场和渗流场的耦合分析, 取得了比较满意的结果。 相似文献
1000.