泥页岩裂缝研究进展   总被引：12，自引：0，他引：12  

丁文龙  许长春  久凯  李超  曾维特  吴礼明 《地球科学进展》2011,26(2):135-144

国内外大量泥岩裂缝油气藏不断发现和近年来北美地区页岩气勘探获得的巨大成功表明,泥页岩裂缝的研究尤为重要.在对国内外泥页岩裂缝研究成果全面系统调研和详细深入分析总结的基础上,认为与其他岩石类型的储层相比,塑性相对较大的泥页岩储层在裂缝类型与成因、裂缝识别方法、裂缝参数估算、裂缝分布预测等方面既有共性也有其特殊性.依据成因...  相似文献   

Defining the concept of stratigraphic grade and applying it to stratal (reservoir) architecture and evolution of the slope-to-basin profile: An outcrop perspective   总被引：1，自引：0，他引：1  

David R. Pyles  James P.M. SyvitskiRoger M. Slatt 《Marine and Petroleum Geology》2011,28(3):675-697

Stratigraphic grade is the similarity of the morphology of successive slope-to-basin profiles in a genetically related depositional system. In this article we use data collected from regional cross-sections of six depositional systems, stratal architecture derived from outcrops of the Lewis Shale (Wyoming, USA), and the Ross Sandstone (Ireland), and supplementary outcrop and subsurface data from other depositional systems to determine how stratigraphic grade relates to stratal (reservoir) architecture in deepwater systems.Four methods are developed that collectively define stratigraphic grade: (1) regional stacking patterns of fourth-order stratigraphic surfaces, (2) the relationship between the trajectory of the shelf edge (T_se) and the trajectory of the depocenter (T_d) for fourth-order stratigraphic units, (3) morphology of the slope-to-basin profiles of fourth-order stratigraphic surfaces, and (4) the similarity of the morphologies of slope-to-basin profiles of fourth-order surfaces in a system (σ_s, σ_r). Several characteristics of stratigraphic (reservoir) architecture of fourth-order stratigraphic cycles are related to stratigraphic grade: (1) longitudinal distribution of sandstone in fourth-order cycles, (2) location of maximum sandstone relative to the depocenter of fourth-order cycles, (3) lengths of fourth-order submarine fans, and (4) longitudinal and vertical distribution of architectural elements. Stratigraphic grade is thus a predictor of reservoir architecture and can thereby be used to reduce the uncertainty in the interpretation of subsurface data.The concept of stratigraphic grade is useful in understanding the stratigraphic evolution of deepwater systems. Most deepwater systems analyzed in this study initiated as out-of-grade and temporally evolved to graded systems over a time span of millions of years. Systems rarely evolve from graded to out-of-grade. First-order controls on stratigraphic grade are determined to be angle of slope, tectonically forced changes in angle of slope during deposition, and sediment supply.  相似文献   

Fracture development in Paleozoic shale of Chongqing area (South China). Part two: Numerical simulation of tectonic stress field and prediction of fractures distribution     

《Journal of Asian Earth Sciences》2013

A tectonics sedimentation evolution has been researched in Southeast Chongqing, and the reasonable Longmaxi shale highstand system tract (HST) and transgressive system tract (TST) geological model were built respectively based on the rock mechanical test and acoustic emission experiment which the samples are from field outcrop and the Yuye-1 well. The Longmaxi shale two-dimension tectonic stress field during the Cenozoic was simulated by the finite element method, and the distribution of fractures was predicted. The research results show that the tectonic stress field and the distribution of fractures were controlled by lithology and structure. As a result of Cretaceous movement, there are trough-like folds (wide spaced synclines), battlement-like folds (similar spaces between synclines and anticlines) and ejective folds (wide spaced anticlines), which are regularly distributed from southeast to northwest in the study area. Since the strain rate and other physical factors such as the viscosity are not taken into account, and the stress intensity is the main factor that determines the tectonic strength. Therefore, the stronger tectonic strength leads the higher stress intensity in the eastern and southeastern study area than in the northwest. The fracture zones are mainly concentrated in the fold axis, transition locations of faults and folds, the regions where are adjacent to faults. The fragile mineral contents (such as siliceous rock, carbonate rock and feldspar) in the shelf facies shale from south of the study area are higher than in the bathyal facies and abyssal facies shale from center of the study area. The shales characterized by low Poisson’s ratio and high elastic modulus from south of the study area are easily broken during Cenozoic orogenic movement.  相似文献   

云南油页岩资源现状及潜力分析     

冯晓宏 《云南地质》2013,(4):369-378

截止目前云南已知油页岩矿点20余处,资源量1.58亿吨,折合页岩油550万吨;含油页岩岩系自寒武系下统—新近系上新统,主要赋存于下寒武统、中泥盆统近底部、中侏罗统、上白垩统和新近系中新统、上新统等层位.除下古生界为滨海—海湾泻湖相和滨外平原相外,其他则为内陆湖泊相.大部分矿点油页岩厚度可以达到最低可采厚度1m以上,含油率也达到或超过油页岩边界品位4ω％.下古生界油页岩含油率普遍较高,最高含油率可达27.07％.云南油页岩矿资源有望成为重要的非常规油气资源.  相似文献   

Identification and micro‐stratigraphy of hyperpycnites and turbidites in Cretaceous Lewis Shale,Wyoming     

OLATUNDO A. SOYINKA  ROGER M. SLATT 《Sedimentology》2008,55(5):1117-1133

Sandy hyperpycnal flows and their deposits, hyperpycnites, have been documented in modern environments and, more recently, in Cretaceous and Tertiary strata; they may be more common in the rock record, and within petroleum reservoirs, than has been previously thought. Muddy hyperpycnites also occur within the rock record, but these are more difficult to document because of their finer‐grained nature and lack of common sedimentary structures. This paper documents the presence of submarine slope mudstone and siltstone hyperpycnites (and muddy turbidites) in the delta‐fed, Upper Cretaceous Lewis Shale of Wyoming; based on field measurements, analyses of rock slabs and thin sections, and laser grain‐size distributions. Four lithofacies comprise laminated and thin‐bedded mudstones that are associated with levéed channel sandstones: (L1) grey, laminated, graded mudstone with thin siltstone and sandstone interbeds; (L2) dark grey to tan, laminated mudstone with very thin siltstone and sandstone stringers; (L3) light grey, laminated siltstones; and (L4) laminated mudstones and siltstones with thin sandstone interbeds. Two styles of mudstone grain‐size grading have been documented. The first type is an upward‐fining interval that typically ranges in thickness from 2·5 to 5 cm. The second type is a couplet of a lower, upward‐coarsening interval and an upper, upward‐fining interval (sometimes separated by a micro‐erosion surface) which, combined, are about 3·8 cm thick. Both individual laminae and groups of laminae spaced millimetres apart exhibit these two grain‐size trends. Although sedimentary structures indicative of traction‐plus‐fallout sedimentary processes associated with sandier hyperpycnites are generally absent in these muddy sediments, the size grading patterns are similar to those postulated in the literature for sandy hyperpycnites. Thus, the combined upward‐coarsening, then upward‐fining couplets are interpreted to be the result of a progressive increase in river discharge during waxing and peak flood stage (upward increase in grain‐size), followed by waning flow after the flood begins to abate (upward decrease in grain‐size). The micro‐erosion surface that sometimes divides the two parts of the size‐graded couplet resulted from waxing flows of sufficiently high velocity to erode the sediment previously deposited by the same flow. Individual laminae sets which only exhibit upward‐fining trends could be either the result of waning flow deposition from either dilute turbidity currents or from hyperpycnal flows. The occurrence of these sets with the size‐graded couplets suggests that they are associated with hyperpycnal processes.  相似文献   

Selenium enrichment in Carboniferous Shales,Britain and Ireland: Problem or opportunity for shale gas extraction?     

《Applied Geochemistry》2016

The Carboniferous Bowland Shale in England, and its correlatives in Ireland, contain anomalously high concentrations of trace elements, including selenium (Se), molybdenum (Mo) and arsenic (As). High levels of these elements reflect high sulphur contents as these elements occur as trace constituents of pyrite. Anomalous Se in particular may have a volcanic provenance, from contemporary volcanic activity and/or drainage from Ordovician volcanogenic sulphide deposits. Following concern over the release of Se and As into groundwater during shale gas extraction in the US, the potential fate of Se and As during any future shale gas extraction from the Bowland Shale merits attention. It is at least an environmental issue that must be managed, but at best it could be an opportunity for extraction of Se in an environmentally sensitive manner.  相似文献   

渝东北下寒武统水井沱组陆棚相黑色页岩沉积演化特征   总被引：1，自引：0，他引：1       下载免费PDF全文

朱瑜  张帆  李少荣 《地质科学》2016,(3):961-977

渝东北地区位于四川中生代前陆盆地和扬子陆块南部被动边缘褶冲带的结合部位,形成东西向密集、大体平行、不对称的背、向斜构造。研究区下寒武统水井沱组发育在克拉通内坳陷形成的滞留盆地沉积环境中,是页岩气富集层位,埋藏深,岩相组合变化大。本文利用地层剖面组合、岩性、标准层、地层厚度和地球化学指标等将水井沱组页岩地层划分为两个三级层序（SQ1、 SQ2）,每个层序又进一步划分为两个体系域,即海侵体系域TST和高位体系域HST。通过野外剖面沉积相分析和沉积相平面展布特征的研究,结合连井剖面、黑色页岩分布规律等分析该区陆棚相黑色页岩沉积演化特征。研究结果表明：该套页岩主要由浅海深水陆棚相、浅水陆棚相和砂质陆棚相组成,为3种陆棚亚相沉积。  相似文献   

吉木萨尔凹陷芦草沟组烃源岩评价及页岩油富集条件探讨          下载免费PDF全文

邱振  陶辉飞  卢斌  吴晓智  杨智  唐勇  崔景伟  周杰 《地质科学》2016,(2):533-546

准噶尔盆地吉木萨尔凹陷芦草沟组为一套优质陆相烃源岩, 是我国当前页岩油气研究的热点地区之一.基于吉木萨尔凹陷18口井芦草沟组约为580 m岩心观察、薄片观察、地球化学测试等数据, 对芦草沟组烃源岩岩石类型、地球化学特征等方面开展了研究与评价, 结果表明: 1)芦草沟组烃源岩整体上为优质烃源岩, 且以Ⅰ-Ⅱ型有机质类型为主, 处于低熟至成熟阶段; 2)烃源岩主要划分为5种类型, 包括纯页岩、白云质页岩、纯泥岩, 白云质泥岩和粉砂质泥岩, 其有机质类型和丰度存在一定差异.综合研究得出, 吉木萨尔凹陷芦草沟组优质有效烃源岩的有机质丰度下限值为2.0%, 并认为TOC≥2.0%的烃源岩段也是该区页岩油发育的有利层段.  相似文献   

Release of selected chemical elements from shale drill cuttings to aqueous solutions of different pH     

《Applied Geochemistry》2016

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Deep groundwater circulation and associated methane leakage in the northern Canadian Rocky Mountains     

《Applied Geochemistry》2016

Concern over potential impact of shale gas development on shallow groundwater systems requires greater understanding of crustal scale fluid movement. We examined natural deeply circulating groundwater systems in northeastern British Columbia adjacent to a region of shale gas development, in order to elucidate origin of waters, depths of circulation, and controls on fluid flow. These systems are expressed as thermal springs that occur in the deformed sedimentary rocks of the Liard Basin. Stable isotope data from these springs show that they originate as meteoric water. Although there are no thermal anomalies in the region, outlet temperatures range from 30 to 56 °C, reflecting depth of circulation. Based on aqueous geothermometry and geothermal gradients, circulation depths up to 3.8 km are estimated, demonstrating connection of deep groundwater systems to the surface. Springs are also characterised by leakage of thermogenic gas from deep strata that is partly attenuated by methanotrophic microbial communities in the spring waters. Springs are restricted to anomalous structural features, cross cutting faults, and crests of fault-cored anticlines. On a regional scale they are aligned with the major tectonic features of the Liard Line and Larsen Fault. This suggests that while connection of surface to deep reservoirs is possible, it is rare and restricted to highly deformed geologic units that produce permeable pathways from depth through otherwise thick intervening shale units. Results allow a better understanding of potential for communication between deep shale gas units and shallow aquifer systems.  相似文献