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天然气水合物在沉积地层中的分布模式 总被引：1，自引：0，他引：1
简要介绍了3种模式的天然气水合物在地层中的分布特征。第1种模式的水合物以胶结物的形式存在,主要分布在火山灰、凝灰质泥和浊流层中,埋深通常较小,孔隙度较高,水合物饱和度较低,沿地层层面分布;第2种模式的水合物以块状(或“鸡窝状”)的形式存在,主要分布在泥质粉砂和粉砂质泥中,埋深通常较大,沉积地层的孔隙度较低,但呈块状(或“鸡窝状”)分布的水合物的饱和度却很高,地震剖面上有时会出现VAMP异常(速度振幅异常),同样沿地层层面分布;第3种模式的水合物主要分布在泥岩或砂质白云岩的裂隙和孔洞中,以小碎块(或细脉状)穿层分布,水合物饱和度通常较低。 相似文献
3.
《海洋地质与第四纪地质》2016,(2)
温度对岩石热导率的影响是一个重要的地热学研究课题。在前人岩石热导率实验的基础上,结合南海西南海次盆地壳实际资料,用数值模拟的方法,对倒数型、直线型和指数型热导率-温度模型系数进行了约束,并对温度对热导率影响条件下莫霍面深度的求解方法以及海底热流与莫霍面温度关系的探讨产生了新的认识。计算结果表明:倒数型(K(T)=a+b/(T+c),a、b、c为常数)和直线型(K(T)=a·T+b,a、b为常数)热导率-温度模型系数呈线性相关,指数型(K(T)=a·ebT,a、b为常数)则更符合二次多项式形式,据此可简化热导率-温度表达式系数个数,使岩石热导率与温度之间的定量化描述更进一步。根据模拟结果与实验室统计结果对比分析得到西南次海盆莫霍面深度为14~16km。通过热导率-温度模型系数反演发现,热导率受温度影响时海底热流值同莫霍面温度呈正相关,当海底热流为100~125mW/m2、莫霍面深度为10.3km时,西南次海盆莫霍面温度为420~540℃,且随莫霍面深度增加而升高,当莫霍面深度增至14~16km时则可达600~1 000℃。 相似文献
4.
综合利用常规测井、核磁共振测井、电阻率成像测井及地层测试数据，并结合岩芯实验分析结果对琼东南盆地松涛凸起区低阻油藏的储层特征进行精细表征，从宏观及微观等多方面深入分析了低阻油藏的成因及主控因素并定量确定低阻油藏的储层下限。结果表明，低阻油藏岩性以细砂岩为主，含少量粉砂岩、泥质粉砂岩及生屑砂岩，孔隙度及渗透率值变化较大，电阻率增大系数<1.5。研究区沉积环境主要为滨岸相环境，细粒物质含量偏高，较小的粒间孔隙及较差的孔隙结构造成地层中束缚水含量偏高，是造成研究区储层电阻率偏低的重要因素，泥浆侵入、导电矿物及黏土矿物附加导电性等对储层电阻率影响较小。在此基础上对低阻油藏储层下限进行了定量分析，确定了研究区低阻油藏储层孔喉半径、孔隙度、渗透率、电阻率、含油饱和度及泥质含量的下限值。此研究为琼东南盆地松涛凸起区低阻油藏的识别及勘探评价提供了理论基础，加速了研究区低阻油藏的开发进程。 相似文献
5.
岩石生热率是研究地球内热的一个重要的参数。本文根据自然伽马与岩石生热率的关系,利用盆地4口钻井的自然伽马测井曲线,计算出桑托斯盆地主要岩石或矿物及地层的生热率。本文统计了2964个自然伽马测井数据值,主要岩石或矿物的生热率从大到小依次为：泥岩、砂岩、页岩、玄武岩、石灰岩、硬石膏和盐岩;盆地地层的生热率随深度增加显著降低,生热率体现出受控于岩性变化的特征。以S1井为例,根据岩石生热率和热流的关系,计算出盆地中各个组的生热率,Marambaia组、Itajai-Acu组、Itanhaem组、Ariri组、Guaratiba群、Camboriu组生热率分别是1.36±0.16μW/m3、1.52±0.15μW/m3、1.30±0.3μW/m3、0.46±0.18μW/m3、0.64±0.23μW/m3、0.37±0.07μW/m3,盆地沉积地层产生的热量占表层大地热流的13.62%,因此沉积地层具有一定的产热潜力,对区域有机质的成熟度有一定的影响。建立了岩石圈分层生热模型,其中地壳热流贡献为15.38mW/m2,占表层大地热流的30.76%,地幔热流贡献值为34.62mW/m2,地壳和地幔的热流比例为0.44,具有“冷壳热幔”的特征。 相似文献
6.
天然热释光技术在海洋油气田勘查中的应用 总被引：18，自引：2，他引：18
沉积物热释光能有效地反映海洋环境下深部油气田引起的微弱放射性异常。热释光在不同的测试粒级、不同的岩性中的丰度不同，结果为粗粒级＞细粒级、砂岩＞粉砂质砂岩＞泥质粉砂岩＞泥岩。热释光也与部分金属元素含量有关，Ti、Ba、Zn、Fe^3 /Fe^2 与热释光呈正相关关系。热释光与烃类也呈较强的正相关性。不同采用深度热释光测量结果表明，热释光剂量随沉积物的沉积深度和沉积时间的增加而增加，深层样的热释光对油气藏的指示效果更好。 相似文献
7.
琼东南盆地深水区中央峡谷黄流组储层特征及主控因素 总被引：2，自引：1，他引：1
在利用钻井和岩心资料基础上,结合铸体薄片、常规物性、压汞实验等分析测试手段,对琼东南盆地深水区中央峡谷黄流组储层特征及其影响因素进行了分析。研究表明,中央峡谷黄流组砂岩以岩屑石英砂岩为主,砂岩粒级较细且分选好,成熟度较高。原生粒间孔为主要孔隙类型,孔隙结构普遍为中孔细喉型。储层物性总体表现为中孔-特高孔、中渗-特高渗的特征。沉积微相和成岩作用是影响黄流组储层物性的主要因素,深水浊流沉积的水道砂岩是发育优质储层的前提,同时中央峡谷特殊的水深和温压条件是影响储层成岩作用的重要因素。海水深度大,而实际地层埋深浅,储层总体处于低温常压环境中,以致成岩作用程度普遍不强,但中央峡谷黄流组储层物性的内在差异仍主要受控于压实作用,中央峡谷自西向东,水深增加,实际地层埋深变浅,压实作用减弱,储层孔隙度和渗透率较好,总体上峡谷东部气层含气饱和度也较西部高。 相似文献
8.
地震解释中,标定、地震解释属性提取时时窗的选取、断裂解释都存在一些主观的不确定性。针对这些问题,模拟实际地震资料的视主频和频宽,采用雷克正子波,进行了正演研究。研究表明：剖面上厚层泥岩／厚层砂岩组合方式、砂层的顶界正对着波峰,这时要获得更多砂岩的信息,提取属性选择时窗应该在波峰下取时窗;大套泥岩中的5m砂和10na砂提取属性选择时窗应该在波峰以下取时窗;大套泥中的15m砂岩、20m砂岩和25m砂岩应以波峰对称来开时窗;剖面上厚层砂岩／厚层泥岩组合方式,泥层的顶界将会正对波谷,此可作为标定时的第二标志层;大断面下往往会出现近断面相位上提、远断面下拉,从而造成断裂假象;煤层（低速）横向相变或突变,将会在相变处或突变处造成断裂解释误区。这些认识应用效果良好。 相似文献
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《中国海洋大学学报(自然科学版)》2017,(3)
针对西湖凹陷中深层普遍存在异常压力的现象,以实测地层压力为约束,结合钻井异常压力预测,在测井约束的波阻抗反演方法反演花港组的层速度的基础上,利用Fillippone公式计算地层压力系数,最终实现平湖斜坡带花港组异常压力的预测。预测结果显示:平湖斜坡带花港组地层泥岩段普遍存在异常高压,且异常高压明显呈带状分布,在垂向上可划分为4个异常高压带。随着花港组地层埋深的增加,异常高压带的压力系数由西向东、由南向北具有逐渐增大的特征,即平湖斜坡带花港组地层异常压力的分布受到泥岩发育和地层埋深的共同影响。 相似文献
10.
新西兰Taranaki MM地层晚中新世深水沉积的野外剖面显示了盆底扇和斜坡扇不同沉积单元下各异的物理沉积特征。通过对砂岩粒度特征的研究，从而来区分这两种类型的深水沉积相。野外露头资料表明：盆底扇相对砂质含量较多，而斜坡扇则碎屑含量相对较高。从交汇图上可以看出，盆底扇和斜坡扇的砂岩样品都有随着粒度增大，分选变好的关系，但是这种关系又有细微的差别。盆底扇和斜坡扇的砂岩样品都随着粒度增大，分选变好的这种关系同样适用于井下样品。这个结论对于一个厚达600m代表了几百万年沉积历史的地层来说是不可思议的。同时，这个发现也意味着一直以来整个盆地有一个统一的沉积结构。
区别盆底扇和斜坡扇是很重要的，特别在包括了油井数据的地下背景时。相对于斜坡扇储层，盆底扇油气勘探地层是显著不同的。岩石学上这种类型的差别对于油田开发的优选是很重要的。对于井下样品，这两种储层砂岩的岩相通常很难区分。粒度变化特征似乎可以模拟细微地区别这两种深水沉积环境的沉积机制。 相似文献
11.
The 380 m thick fine-grained Vischkuil Formation comprises laterally extensive hemipelagic mudstones, separated by packages of graded sandstone and siltstone turbidites, and volcanic ash beds, and is an argillaceous precursor to a 1 km thick sand-prone basin floor fan to shelf succession. The Vischkuil Formation provides an insight into the process by which regional sand supply is initiated and for testing sequence stratigraphic principles in a basin plain setting. Regionally mapped 1–2 m thick hemipelagic mudstone units are interpreted as condensed drapes that represent the starved basin plain equivalents of transgressive systems tracts and maximum flooding surface on the coeval shelf (now removed during later uplift). The section above each mudstone drape comprises siltstone turbidites interpreted as highstand systems tract deposits and a surface of regional extent, marked by an abrupt grain size shift to fine sandstone. These surfaces are interpreted as sequence boundaries, related to abrupt increases in flow volume and delivery of sand grade material to the basin-plain. The interpreted lowstand systems tract comprises sandstone-dominated turbidites and is overlain by another hemipelagic mudstone drape. The upper Vischkuil Formation is marked by three 20–45 m thick debrites, with intraformational sandstone clasts up to 20 cm in diameter that can be mapped over 3000 km2. In each case, debrite emplacement resulted in widespread deformation of the immediately underlying 3–10 m of silty turbidites. A sequence boundary is interpreted at the base of each deformation/debrite package. Six depositional sequences are recognised and the interfered energy shift across each successive sequence boundary and LSTs include a larger volume of sandstone increases up section. The lower two sequences thin to the NW and show NW-directed palaeocurrents. The four overlying sequences show a polarity switch in palaeocurrent directions and thinning, to the E and SE. Sequence 6 is overlain sharply by the 300 m thick sandstone dominated Fan A of the Laingsburg Formation. The LST debrites may indicate gradual development of major routing conduits that subsequently fed Fan A. The polarity shift from westward flowing turbidity currents to an eastward prograding deepwater to shelf system represents establishment of a long term feeder system from the west. Sand supply to the Karoo basin floor was established in an incremental, stepwise manner. Given the early post-glacial setting in an icehouse climate, glacio-eustatic sea-level changes are considered to have been the main control on sequence development. 相似文献
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In this study, the deformation induced by the first wetting typically referred to as wetting deformation of a sandstone–mudstone particle mixture is examined. Wetting deformation can lead to collapse-inducing cracks. The cracks may weaken the strength of the structure. To investigate the first wetting-induced deformation of the sandstone and mudstone particle mixture, three triaxial tests were conducted. Two of the triaxial tests used saturated soil and dry soil. These tests were used to calculate the strain under the condition of minimized deviator stress ratio at wetting. The third triaxial test accesses various deviator stress ratios at wetting. Additionally, the influence on axial and volumetric strain of wetting at varying levels of the confining stress and deviator stress ratios at wetting was evaluated. The wetting axial and volumetric strains were found to increase with an increased confining stress and deviator stress ratio at wetting. The relationships between the wetting axial strain and deviator stress ratio at wetting yielded a logarithmic curve for various levels of confining stress. In contrast, the wetting volumetric strain yielded a direct relationship with the deviator stress ratio at wetting for various levels of confining stress. Based on these results, two equations for predicting the wetting axial and volumetric strains are suggested. 相似文献
13.
Jun-Jie Wang Zhen-Feng Qiu Wen-Jie Deng Hui-Ping Zhang 《Marine Georesources & Geotechnology》2016,34(4):395-402
The present study focuses on the shear strength, deformation, and particle crushing of sand which is mixed by crushed sandstone and mudstone particles. Two triaxial tests—one for unsaturated specimens and the other for saturated specimens—were performed, along with sieve analysis tests. Results obtained from the triaxial tests indicate that, with the increment of the mudstone particle content by weight, the angle of internal friction decreases, the cohesion increases and then decreases, and both the initial angle of shearing resistance at the atmospheric pressure and decremental angle increase and then decrease. Compared to the unsaturated specimens, the deviator stress or normalized deviator stress of the saturated specimens at the same axial stress may decrease due to the wetting action. Thus, the shear strength of the tested materials may be reduced by the wetting action. Results of sieve analysis tests indicate that the mixing of some mudstone particles into the sandstone particle mixture may reduce the amount of particle crushing, but the wetting action may increase the amount. The amount of the crushed particle may arrive at a minimum of 40% of mudstone particle content by weight. 相似文献
14.
Reservoir pressures within the Bullwinkle minibasin (Green Canyon 65, Gulf of Mexico continental slope) increase at a hydrostatic gradient whereas pressures predicted from porosity within mudstones bounding these reservoirs increase at a lithostatic gradient: they are equal at a depth 1/3 of the way down from the crest of the structure. Two- and three-dimensional steady-state flow models demonstrate that bowl-shaped structures will have lower pressures than equivalent two-dimensional structures and that if a low permeability salt layer underlies the basin, the pressure is reduced. We conclude that at Bullwinkle, pressure is reduced due to an underlying salt body and the bowl-shape of the basin. A geometric approach to predict sandstone pressure is to assume that the reservoir pressure equals the area-weighted average of the mudstone pressure. When the mudstone pressure gradient is constant, as at Bullwinkle, the reservoir pressure equals the mudstone pressure at the average depth (centroid) of the reservoir. 相似文献
15.
基于热探针法原理,测试了在杭州湾以东陆架区取得的28个海底表层柱状样0.2、1.0和1.8 m处的导热系数,结合激光粒度分析结果,比较了研究区6种土导热系数的大小,发现含砂量大于10%的粗粒土拥有较大的导热系数。土质类型相同时,含水量和干密度对其导热系数影响显著。杭州湾沉积区、混合沉积区,陆架砂质沉积区表层土导热系数的平均值分别是:1.25、1.45 和1.46 W·m-1·K-1,呈现出由近岸向外海增大的趋势。而土样导热系数在垂向的变化表明:水深、埋深等空间分布因素对海洋土的热物性没有直接影响。 相似文献
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The South Caspian Basin contains major hydrocarbon reservoirs within the largely Early Pliocene Productive Series. This paper describes and contrasts outcrops of the uppermost ∼500 m of the series (the Surakhany Suite) deposited by two of the main fluvial systems that supplied the Azeri margin of the basin. Sedimentary facies and, for the first time from the Productive Series, palynological analyses document fluvial channel belt complexes, sheetflood overbank and flood plain to flood plain lake environments. The Productive Series on the Apsheron Peninsula, Azerbaijan, was supplied predominantly from the north by the palaeo-Volga river system. It displays an overall fining-upward trend, such that the Surakhany Suite at Lokbatan is dominated by mudstone. Siltstone and coarser-grained sediments make up 28% of the section. Channel bodies are on average 1.5 m thick and form 13% of the succession. In the sub-surface of the Apsheron Peninsula, ratty wireline log responses also indicate that siltstone and sandstone bodies are predominantly thin bedded, with SP-derived net-to-gross sand ratios of ∼0.35–0.40. The succession in the Kura Basin was sourced predominantly from the west by the palaeo-Kura river system. It displays a coarsening-upward trend, such that in the middle and upper Surakhany Suite at Babazanan siltstone and coarser sediments make up 52% of the section. It is characterised by numerous stacked and laterally continuous channel sandstone bodies that are on average 5.8 m thick and comprise 42% of the outcrop. In the sub-surface of the Kura Basin, wireline log responses of the Surakhany Suite have a blocky character and indicate SP-derived net-to-gross sand ratios of 0.26–0.38. These values are similar to calculated sandstone volumes at outcrop (44%). The palynological data, including multivariate analyses, show that the main controls on palynomorph distribution are the degree of fluvial or lacustrine influence, subaerial exposure and salinity. Despite their more lithic nature, Surakhany Suite sandstones derived from the palaeo-Kura river system along the Kurovdag-Babazanan-Neftchala trend have similar or better petrophysical properties than those derived from the palaeo-Volga river on the Apsheron Peninsula and its offshore continuation. This is probably due to their coarser-grain size. This, combined with their greater sandstone body thickness, would suggest that the axis of the Kura Basin forms the most promising part of the Azeri sector of the South Caspian Basin for exploration within the uppermost part of the Productive Series. 相似文献
18.
A 120 m thick section of the Cozy Dell Formation (middle Eocene), southem California, consists of a graylaminated mudstone and a tanungraded mudstone; sandstone beds are associated with the laminated mudstone. Sedimentary structures, stratification sequences, foraminiferal
distributions, and composition indicate that the ungraded mudstone is an upper slope hemipelagic deposit, while the laminated
mudstone is an overbank deposit associated with shallow channels or gullies in which the sandstone beds were deposited. This
depositional setting may be analogous to that of the modern Mississippi River delta front. 相似文献
19.
由于存在部分泥岩井眼垮塌,东海春晓气田测井曲线砂泥岩阻抗部分叠置。针对这一现象,采用未垮塌段泥岩伽马与密度拟合关系校正垮塌段泥岩密度,声波时差经本区伽德那公式拟合后求取。通过泥岩垮塌测井数据校正前后对比、直方交会、岩石物理、正演及反演效果分析,认为校正后的测井数据比较真实地反映垮塌段扩径泥岩地层特征,储层与围岩波阻抗差异明显,为储层反演、砂体空间展布分析提供了有力依据。 相似文献
20.
The Mio-Pliocene Misaki Formation, Miura Peninsula, Japan is characterized by alternation of mafic scoriaceous pebbly sandstone, pumiceous sandstone and siltstone, and mudstone formed in a fore-arc basin in an arc–arc collisional zone. The qualitative as well as quantitative evidences of tide during the Misaki sedimentation in the Jogashima area, Miura Peninsula are presented here. The lunar synodic period of ∼28 days/lunar month extracted from the Misaki tidal rhythmite agrees well with the published Miocene tidal rhythmite data. The couplet series of the Misaki tidal rhythmite, however, is often interrupted by downslope resedimentation via turbidity currents, intense penecontemporaneous deformation and bioturbation. Association of deep sea turbidites, mass flow deposits and tidal rhythmite suggest Misaki sedimentation in the Miura Peninsula took place in a submarine canyon setting. 相似文献