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1.
Tom Myers 《Ground water》2012,50(6):872-882
Hydraulic fracturing of deep shale beds to develop natural gas has caused concern regarding the potential for various forms of water pollution. Two potential pathways—advective transport through bulk media and preferential flow through fractures—could allow the transport of contaminants from the fractured shale to aquifers. There is substantial geologic evidence that natural vertical flow drives contaminants, mostly brine, to near the surface from deep evaporite sources. Interpretative modeling shows that advective transport could require up to tens of thousands of years to move contaminants to the surface, but also that fracking the shale could reduce that transport time to tens or hundreds of years. Conductive faults or fracture zones, as found throughout the Marcellus shale region, could reduce the travel time further. Injection of up to 15,000,000 L of fluid into the shale generates high pressure at the well, which decreases with distance from the well and with time after injection as the fluid advects through the shale. The advection displaces native fluids, mostly brine, and fractures the bulk media widening existing fractures. Simulated pressure returns to pre‐injection levels in about 300 d. The overall system requires from 3 to 6 years to reach a new equilibrium reflecting the significant changes caused by fracking the shale, which could allow advective transport to aquifers in less than 10 years. The rapid expansion of hydraulic fracturing requires that monitoring systems be employed to track the movement of contaminants and that gas wells have a reasonable offset from faults. 相似文献
2.
ZHAO Wenzhi WANG Zhaoyun HE Haiqing ZHANG Mingjie WANG Hongjun WANG Yunpeng & QIN Yong . Research Institute of Petroleum Exploration & Development PetroChina Beijing China . PetroChina Exploration & Production Beijing China . Department of Geology Lanzhou University Lanzhou China . Guangzhou Geochemical Institute Chinese Academy of Sciences Guangzhou China . China University of Mining Technology Xuzhou China 《中国科学D辑(英文版)》2005,48(4):441-453
It has been proven in exploration practice that thecarbonates in China not only can generate hydrocar-bons, but also form commercial reservoirs. The car-bonates are different from clastic rocks in view of theirdeposition environment as well as their sedimentaryand diagenetic processes. Therefore, the evaluationcriteria and hydrocarbon generation mechanism forcarbonates can not be the same as that for clasticrocks, and it is important to establish a special hydro-carbon generation mechanism and… 相似文献
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实际的地球介质十分复杂,远非当今人们所采用的理想模型可以概括,因为其属性和结构的变异是非均匀、非线性和各向异性的.在研究地球内部壳幔介质与结构、构造与属性差异、金属矿产资源和油、气、煤能源的勘查中,无论是区域构造格局、岩相和结构特征(如裂缝、破碎带、不同尺度的洞穴以及一些不规则几何体)均十分复杂.近年来基于成山、成盆、成矿、成岩和成灾研究的不断深化,对地下介质各向异性的研究受到广泛的关注.地震波动传播理论和介质与结构的物理属性研究结果表明:地震各向异性在成因上主要是由岩石、矿物和晶体的晶格优势取向、应力场异常变异和构造裂缝与深部物质运移造成的.为此,本文对14次地震各向异性会议的主体内涵进行分析,在此基础上,指出了在各向异性研究的发展进程中、特别是在应用中尚存在着的一些问题.在深化认识地球内部物质物理属性的基础上,探讨了S波分裂和偏振效应与地震各向异性与介质结构分区、构造活动,油气田勘探与岩相特征,裂隙与构造精细刻划和地震活动区(带)深部介质与构造环境的深层过程和动力学响应的关系.最后提出了地震各向异性在地球物理学发展中的作用和今后的任务. 相似文献
5.
Zou Caineng Yang Zhi Sun Shasha Zhao Qun Bai Wenhua Liu Honglin Pan Songqi Wu Songtao Yuan Yilin 《中国科学:地球科学(英文版)》2020,63(7):934-953
The Sichuan Basin is rich in shale oil and gas resources, with favorable geological conditions that the other shale reservoirs in China cannot match. Thus, the basin is an ideal option for fully "exploring petroleum inside source kitchen" with respect to onshore shale oil and gas in China. This paper analyzes the characteristics of shale oil and gas resources in the United States and China, and points out that maturity plays an important role in controlling shale oil and gas composition. US shale oil and gas exhibit high proportions of light hydrocarbon and wet gas, whereas Chinese marine and transitional shale gas is mainly dry gas and continental shale oil is generally heavy. A comprehensive geological study of shale oil and gas in the Sichuan Basin reveals findings with respect to the following three aspects. First, there are multiple sets of organic-rich shale reservoirs of three types in the basin, such as the Cambrian Qiongzhusi Formation and Ordovician Wufeng Formation-Silurian Longmaxi Formation marine shale, Permian Longtan Formation transitional shale, Triassic Xujiahe Formation lake-swamp shale, and Jurassic lacustrine shale. Marine shale gas enrichment is mainly controlled by four elements: Deep-water shelf facies, moderate thermal evolution, calcium-rich and silicon-rich rock association, and closed roof/floor. Second, the "sweet section" is generally characterized by high total organic carbon, high gas content, large porosity, high brittle minerals content, high formation pressure,and the presence of lamellation/bedding and natural microfractures. Moreover, the "sweet area" is generally characterized by very thick organic-rich shale, moderate thermal evolution, good preservation conditions, and shallow burial depth, which are exemplified by the shale oil and gas in the Wufeng-Longmaxi Formation, Longtan Formation, and Daanzhai Member of the Ziliujing Formation. Third, the marine, transitional, and continental shale oil and gas resources in the Sichuan Basin account for 50%, 25%, and 30% of the respective types of shale oil and gas geological resources in China, with great potential to become the cradle of the shale oil and gas industrial revolution in China. Following the "Conventional Daqing-Oil"(i.e., the Daqing oilfield in the Songliao Basin) and the "Western Daqing-Oil Gas"(i.e., the Changqing oilfield in the Ordos Basin), the Southwest oil and gas field in the Sichuan Basin is expected to be built into a "Sichuan-Chongqing Daqing-Gas" in China. 相似文献
6.
在油气勘探与开发过程中,寻求能够从地震资料中直接识别储层油气的流体指示因子至关重要.由于现存多数流体指示因子都是在Biot理论假设前提下建立起来的,因此在双相孔隙介质条件下不能有效地识别流体.为此,本文基于前人提出的双孔介质统一波动理论,考虑岩石裂缝间挤喷流效应,在经典流体指示因子基础上构建了一种新的流体指示因子.该流体因子能够较好地反映岩石内孔隙流体的变化对波传播产生的影响.在实际资料的应用中,采用多种方法分析、对比该流体识别因子与以Biot理论为基础的传统流体因子的优劣,理论分析与实际资料的验证表明该流体因子对于储层中油气的检测有较高的精度和灵敏度. 相似文献
7.
Gui-Hong Guo Jian-Ping Yan Zhi Zhang José Badal Jian-Wu Cheng Shuang-Hu Shi Ya-Wei Ma 《应用地球物理》2018,15(2):299-310
Elastic wave propagation and attenuation in porous rock layers with oriented sets of fractures, especially in carbonate reservoirs, are anisotropic owing to fracture sealing, fracture size, fracture density, filling fluid, and fracture strike orientation. To address this problem, we adopt the Chapman effective medium model and carry out numerical experiments to assess the variation in P-wave velocity and attenuation, and the shear-wave splitting anisotropy with the frequency and azimuth of the incident wave. The results suggest that velocity, attenuation, and anisotropy vary as function of azimuth and frequency. The azimuths of the minimum attenuation and maximum P-wave velocity are nearly coincident with the average strike of the two sets of open fractures. P-wave velocity is greater in sealed fractures than open fractures, whereas the attenuation of energy and anisotropy is stronger in open fractures than sealed fractures. For fractures of different sizes, the maximum velocity together with the minimum attenuation correspond to the average orientation of the fracture sets. Small fractures affect the wave propagation less. Azimuth-dependent anisotropy is low and varies more than the other attributes. Fracture density strongly affects the P-wave velocity, attenuation, and shear-wave anisotropy. The attenuation is more sensitive to the variation of fracture size than that of velocity and anisotropy. In the seismic frequency band, the effect of oil and gas saturation on attenuation is very different from that for brine saturation and varies weakly over azimuth. It is demonstrated that for two sets of fractures with the same density, the fast shear-wave polarization angle is almost linearly related with the orientation of one of the fracture sets. 相似文献
8.
Rui-Zhao Yang Zheng-Guang Zhao Wei-Jun Peng Yu-Bo Gu Zhan-Gang Wang Xi-Qin Zhuang 《应用地球物理》2013,10(2):157-169
The development of unconventional resources, such as shale gas and tight sand gas, requires the integration of multi-disciplinary knowledge to resolve many engineering problems in order to achieve economic production levels. The reservoir heterogeneity revealed by different data sets, such as 3D seismic and microseismic data, can more fully reflect the reservoir properties and is helpful to optimize the drilling and completion programs. First, we predict the local stress direction and open or close status of the natural fractures in tight sand reservoirs based on seismic curvature, an attribute that reveals reservoir heterogeneity and geomechanical properties. Meanwhile, the reservoir fracture network is predicted using an ant-tracking cube and the potential fracture barriers which can affect hydraulic fracture propagation are predicted by integrating the seismic curvature attribute and ant-tracking cube. Second, we use this information, derived from 3D seismic data, to assist in designing the fracture program and adjusting stimulation parameters. Finally, we interpret the reason why sand plugs will occur during the stimulation process by the integration of 3D seismic interpretation and microseismic imaging results, which further explain the hydraulic fracture propagation controlling factors and open or closed state of natural fractures in tight sand reservoirs. 相似文献
9.
海底冷泉渗漏是海洋环境中广泛分布的自然现象.本文主要介绍海底冷泉原住观测技术及全球几个典型冷来渗漏活动地区的原位观测结果.冷泉渗漏活动主要发育在海底裂隙和断层发育的地区,海底常有泥火山、麻坑、水合物、冷泉生物群落和冷泉碳酸盐岩的发育.冷泉渗漏主要包括液体和气体两种形式,流体流动包括上升流和下降流两种方式,流量变化大,主要与海底环境及构造作用有关.烃类渗漏是以气泡、油滴的形式沿断层向海底喷溢,释放量大,运移过程主要受涌浪、静水压力和裂隙压力等因素控制.冷泉渗漏活动是复杂的水文地质过程,受水合物形成和分解产生的气藏的充注和排空、深部常规油气藏的破坏及海底环境变化等多种作用的控制. 相似文献
10.
Localization of fractured areas is of primary interest in the study of oil and gas geology in carbonate environments. Hydrocarbon reservoirs in these environments are embedded within an impenetrable rock matrix but possess a rich system of various microheterogeneities, i.e., cavities, cracks, and fractures. Cavities accumulate oil, but its flow is governed by a system of fractures. A distinctive feature of wave propagation in such media is the excitation of the scattered/diffracted waves by the microheterogeneities. This scattering could be a reliable attribute for characterization of the fine structure of reservoirs, but it has extremely low energy and any standard data processing renders them practically invisible in comparison with images produced by specular reflections. Therefore, any attempts to use these waves for image congestion of microheterogeneities should first have a preliminary separation of the scattering and specular reflections. In this paper, the approach to performing this separation is based on the asymmetric summation. It is implemented by double focusing of Gaussian beams. To do this, the special weights are computed by propagating Gaussian beams from the target area towards the acquisition system separately for sources and receivers. The different mutual positioning of beams in each pair introduces a variety of selective images that are destined to represent some selected singular primitives of the target objects such as fractures, cavities, and edges. In this way, one can construct various wave images of a target reservoir, particularly in scattered/diffracted waves. Additional removal of remnants of specular reflections is done by means of spectral analysis of the scattered/diffracted waves' images to recognize and cancel extended lineaments. Numerical experiments with Sigsbee 2A synthetic seismic data and some typical structures of the Yurubcheno‐Tokhomskoye oil field in East Siberia are presented and discussed. 相似文献
11.
R.E. Jackson A.W. Gorody B. Mayer J.W. Roy M.C. Ryan D.R. Van Stempvoort 《Ground water》2013,51(4):488-510
Unconventional natural gas extraction from tight sandstones, shales, and some coal‐beds is typically accomplished by horizontal drilling and hydraulic fracturing that is necessary for economic development of these new hydrocarbon resources. Concerns have been raised regarding the potential for contamination of shallow groundwater by stray gases, formation waters, and fracturing chemicals associated with unconventional gas exploration. A lack of sound scientific hydrogeological field observations and a scarcity of published peer‐reviewed articles on the effects of both conventional and unconventional oil and gas activities on shallow groundwater make it difficult to address these issues. Here, we discuss several case studies related to both conventional and unconventional oil and gas activities illustrating how under some circumstances stray or fugitive gas from deep gas‐rich formations has migrated from the subsurface into shallow aquifers and how it has affected groundwater quality. Examples include impacts of uncemented well annuli in areas of historic drilling operations, effects related to poor cement bonding in both new and old hydrocarbon wells, and ineffective cementing practices. We also summarize studies describing how structural features influence the role of natural and induced fractures as contaminant fluid migration pathways. On the basis of these studies, we identify two areas where field‐focused research is urgently needed to fill current science gaps related to unconventional gas extraction: (1) baseline geochemical mapping (with time series sampling from a sufficient network of groundwater monitoring wells) and (2) field testing of potential mechanisms and pathways by which hydrocarbon gases, reservoir fluids, and fracturing chemicals might potentially invade and contaminate useable groundwater. 相似文献
12.
塔河油田碳酸盐岩缝洞型储层的测井识别与评价方法研究 总被引：12，自引：4，他引：12
塔河油田奥陶系以碳酸盐岩为主，油气的主要储渗空间为裂缝和溶蚀孔洞，具有很强的非均质性．本文利用常规及成像测井资料，对碳酸盐岩缝洞型储层的识别与评价方法进行研究．为了综合各种测井方法识别裂缝，建立了综合裂缝概率模型，计算综合裂缝概率指示裂缝的发育程度．利用地层微电阻率扫描成像测井资料进行裂缝和溶蚀孔洞的定性、定量解释．定量计算的裂缝参数为：裂缝密度、裂缝长度、裂缝平均宽度、平均水动力宽度、裂缝视孔隙度；定量计算的溶蚀孔洞参数有：面孔率、孔洞密度．根据缝洞型储层孔隙空间类型及其中子孔隙度、补偿密度、声波、双侧向电阻率的测井响应物性特征，建立缝洞型碳酸盐岩储层复杂孔隙介质解释模型，用于确定裂缝、溶蚀孔洞孔隙度和评价储层． 相似文献
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Geochemical features and genesis of the natural gas and bitumen in paleo-oil reservoirs of Nanpanjiang Basin, China 总被引：4，自引：0，他引：4
ZHAO MengJun ZHANG ShuiChang ZHAO Lin & DA Jiang Research Institute of Exploration Development PetroChina Beijing China Guizhou Institute of Petroleum Geology Southern Petroleum Exploration Development Corp. Sinopec Guiyang China 《中国科学D辑(英文版)》2007,50(5):689-701
Bitumen from the Nanpanjiang Basin occurs mainly in the Middle Devonian and Upper Permian reef limestone paleo-oil reservoirs and reserves primarily in holes and fractures and secondarily in minor matrix pores and bio-cavities. N2 is the main component of the natural gas and is often associated with pyrobitumen in paleo-oil reservoirs. The present study shows that the bitumen in paleo-oil reservoirs was sourced from the Middle Devonian argillaceous source rock and belongs to pyrobitumen by crude oil cracking under high temperature and pressure. But the natural gas with high content of N2 is neither an oil-cracked gas nor a coal-formed gas generated from the Upper Permian Longtan Formation source rock, instead it is a kerogen-cracked gas generated at the late stage from the Middle Devonian argilla- ceous source rock. The crude oil in paleo-oil reservoirs completely cracked into pyrobitumen and methane gas by the agency of hugely thick Triassic deposits. After that, the abnormal high pressure of methane gas reservoirs was completely destroyed due to the erosion of 2000--4500-m-thick Triassic strata. But the kerogen-cracked gas with normal pressure was preserved under the relatively sealed condition and became the main body of the gas shows. 相似文献
14.
《中国科学D辑(英文版)》2008,(Z1)
Shallow gas reservoirs are distributed widely in Chinese heavy oil-bearing basins.At present,shallow gas resources have opened up giant potentials.The previous researches indicate the intimate genetic relationship between shallow gas and heavy oil.Shallow gas resources are generated from crude oil degraded by anaerobic microscopic organism,it belongs to biogenic gas family of secondary genesis, namely heavy oil degraded gas.Shallow gas resources are usually distributed in the upward position or the vicinity of heavy oil reservoirs.They are mainly of dry gas,which are composed of methane and only tiny C2 heavy hydrocarbon and relatively higher contents of nitrogen gas.Generally,methane isotopes are light,whose values are between biogenic gas and thermal cracking gas.Ethane isotopes are heavy,which mixed possibly with thermogenic gas.Carbon dioxide bear the characteristics of very heavy carbon isotope,so carbon isotopic fractionation effects are very obvious on the process of microscopic organism degradation crude oil.The heavy oil degraded gas formation,a very complex geological,geochemical and microbiological geochemical process,is the result of a series of reactions of organic matter-microbes and water-hydrocarbon,which is controlled by many factors. 相似文献
15.
An analysis of local seismicity within the Klyuchevskoi Volcanic Cluster and Shiveluch Volcano for the period 2000–2017 revealed a sequence of plane-oriented earthquake clusters that are interpreted here as the emplacement of dikes and sills (magmatic fracking). The geometry of magma bodies reflects the geomechanical conditions in volcanic plumbing systems and at the bases of the volcanoes. Magmatic fracking within active magmatic plumbing systems results in the formation of permeable reservoirs whose vertical extent can reach 35 km (Klyuchevskoi) and can be as wide as 15 km across (Shiveluch), depending on the geomechanical condition of the host rocks. These reservoirs will be the arena of subsequent hydrothermal circulation, producing geothermal and ore fields, as well as hydrocarbon fields. TOUGH2-EOS1sc simulation tools were used to estimate the conditions for the formation of hydrothermal reservoirs at temperatures below 1200°С and pressures below 1000 bars. 相似文献
16.
由于流体本身的粘滞性和摩擦性,使得地震波在含油气地层中传播时衰减形成低频阴影.通过对叠后地震资料做时频分解,分析地层衰减特征,是当前除了AVO技术之外,比较流行的直接识别流体和气藏的技术.本文基于波动方程正演,模拟了地震波对含油气地层的响应.然后采用连续小波变换分析不同尺度剖面的瞬时能量特征,提取分频剖面上每一个点的峰值能量对应的频率,得到瞬时峰值能量频率剖面.通过分析瞬时峰值能量频率剖面,分析了地震波在地下介质中传播时的衰减特征.最后应用此方法对实际地震剖面进行了分析,验证了其有效性. 相似文献
17.
断裂（裂缝）对油气藏既有破坏又有保存作用。胜利埕岛奥陶系潜山油藏受裂缝控制，非均质性强，勘探目标预测难度大。本文以地震边缘检测为先验信息和启发因子，在自适应地震相干数据体上进行蚂蚁体追踪，精细检测裂缝，弥补了单一相干体检测分辨低的缺陷，获得了与钻井和实际地下情况吻合度更高的裂缝检测结果。对该区的油气勘探起到了指导作用。 相似文献
18.
近几年受地震属性分析技术的启发,出现了利用测井属性分析泥页岩裂缝油气藏的新方法.为了避免常规测井信号受到噪声干扰影响裂缝识别效果,利用小波变换的高频属性对裂缝识别展开研究.以贵州岑巩地区下寒武统牛蹄塘组的泥页岩裂缝性油气藏为例,观察和分析野外黑色页岩露头、岩心薄片及镜下照片,总结了该地区裂缝发育特征和成因;然后着重利用研究区的测井资料,运用小波阈值去噪和小波高频属性方法对裂缝进行了识别.研究结果表明:研究区主要发育高角度剪性缝、张剪性缝、低角度滑脱缝及层间缝,采用的小波阈值去噪方法具有高信噪比和低均方差特点,在保留原始信号特点的基础上得到更加真实的信号;通过小波高频属性方法提取了声波时差信号中的高频信号,识别出了常规测井方法无法识别的泥页岩裂缝,该套方法成功在贵州岑巩页岩气裂缝识别中得到成功应用,并具有一定的借鉴意义. 相似文献
19.
The southeastern Karoo Basin is considered to be one of the most prospective areas for shale gas exploration in South Africa. An interesting magnetic anomaly, the Beattie magnetic anomaly (BMA), and geologic intrusions are seen on the magnetic map. To date, the source of the BMA and interconnectivity of the igneous intrusions are not well understood. In this study, we investigate the interconnectivity of the igneous intrusions and possible location of the source of the BMA using gravity and magnetic methods. The gravity model results showed that igneous intrusions are interconnected at depth, which probably pose threat by increasing the risk of fracking the Karoo for shale gas exploration. The magnetic results revealed that the BMA becomes stronger with depth. The average depths to the top of the shallow and deep magnetic sources were estimated to be approximately 0.6 and 15 km, respectively. 相似文献
20.
GuangYou Zhu ShuiChang Zhang WenZhi Zhao ZhengJun Wang YingBo Liang XueFeng Zhao JingYan Zhang 《中国科学D辑(英文版)》2008,51(1):96
Shallow gas reservoirs are distributed widely in Chinese heavy oil-bearing basins. At present, shallow gas resources have opened up giant potentials. The previous researches indicate the intimate genetic relationship between shallow gas and heavy oil. Shallow gas resources are generated from crude oil degraded by anaerobic microscopic organism, it belongs to biogenic gas family of secondary genesis, namely heavy oil degraded gas. Shallow gas resources are usually distributed in the upward position or the vicinity of heavy oil reservoirs. They are mainly of dry gas, which are composed of methane and only tiny C 2 + heavy hydrocarbon and relatively higher contents of nitrogen gas. Generally, methane isotopes are light, whose values are between biogenic gas and thermal cracking gas. Ethane isotopes are heavy, which mixed possibly with thermogenic gas. Carbon dioxide bear the characteristics of very heavy carbon isotope, so carbon isotopic fractionation effects are very obvious on the process of microscopic organism degradation crude oil. The heavy oil degraded gas formation, a very complex geological, geochemical and microbiological geochemical process, is the result of a series of reactions of organic matter-microbes and water-hydrocarbon, which is controlled by many factors. 相似文献