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神府解家堡区构造上位于鄂尔多斯盆地东缘晋西挠褶带,上古生界自下而上发育本1段、太2段、山2段和千5段等多套致密砂岩储集层.储层岩石类型以石英砂岩、岩屑石英砂岩、长石石英砂岩、岩屑砂岩和长石岩屑砂岩为主,自下而上储层石英含量呈递减、岩屑和长石含量呈递增趋势.储集空间类型以粒间溶孔、粒内溶孔、晶间孔和微裂缝为主,储层最大孔隙半径总体偏小,孔隙中值半径较小,排驱压力中等,储层孔隙以小孔—微孔为主.本溪组海相障壁—潮坪沉积、太原组浅水三角洲沉积、山西组三角洲沉积和石千峰组陆相辫状河沉积演化序列下,岩石成分成熟度和结构成熟度自下而上降低,储层空间展布呈层多而薄、砂—泥—煤岩交互特征.成岩作用类型以压实、胶结、溶蚀作用为主,局部发育高岭石化和微裂缝.以沉积相带、岩石类型和成岩作用类型作为3个控制端元,以孔隙度和渗透率为标准,上古生界致密砂岩储层可划分为4个大类和10个亚类,优势相和强溶蚀、弱胶结作用下的Ⅰ类储层孔隙度大于8%,渗透率大于0.5 mD,是最优质储层. 相似文献
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Md. Aminul Islam 《Journal of the Geological Society of India》2010,76(6):621-631
The present study has been carried out for core and log based petrophysical evaluation of subsurface reservoir sandstones considering at least one well from each of the Kailas Tila, Titas, Bakhrabad and Shahbazpur gas fields of Bangladesh. Core analysis results show that average core porosity, permeability and pore throat values are 20%, 209 mD and 44020 Å, respectively. These measured values support that the sandstone reservoirs are categorized as good quality reservoirs. Core porosity values usually exceed thin section porosity. Different cross-plots indicate that permeability is largely dependent on porosity. Permeability and porosity are also dependent on textural parameters that include size, shape, sorting and matrix of the reservoir sandstones. It reveals from both thin section study and different cross plots that diagenetic cements are the main controlling factors of the reservoirs. Quantitative determination of the volume of cements shows that cements have inverse correlation with porosity and permeability. Log based petrophysical parameters include shale volume, porosity, water and hydrocarbon saturation, permeability, moveability index and bulk volume of water. The average values of the mentioned parameters are 20%, 22%, 26%, 74%, 110 mD, 0.28 and 0.05, respectively. The most important parameters are porosity and permeability, which indicate that log porosity exceeds core porosity and log permeability significantly lags behind core permeability. The study also reveals that 23 gas zones covering total thickness of 385 m sandstones mostly posses good quality reservoirs except few moderate quality reservoirs. 相似文献
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通过铸体薄片显微镜下观察、孔喉图像、毛细管压力、恒速压汞、气水相对渗透率、核磁共振等多种分析实验手段,研究了鄂尔多斯盆地东部上古生界盒8段低孔、低渗-特低渗砂岩储层的微观孔隙结构和渗流特征,探讨了孔隙结构对储层渗流特征的影响。结果表明,孔隙结构特征是影响低孔、低渗-特低渗砂岩储集性能与渗流特征的主要因素。而砂岩的孔隙结构特征主要受砂岩原生矿物组合与成岩演化过程及其产物的控制,盒8段各砂岩类型由于其矿物成分不同导致孔隙结构的差异,也是各砂岩类型储集性能与渗流能力存在差别的直接原因。在孔隙结构参数中,喉道的大小、有效孔隙与喉道的体积及其连通性是决定储层储集与渗流能力的关键。大孔喉对储层渗流能力的贡献更大,中-小孔喉则对储集能力的贡献相对较高。微裂缝是除孔隙结构以外影响砂岩储集性能与渗流特征的重要因素。 相似文献
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金湖凹陷戴南组储层总体为一套中低孔-中低渗碎屑储层,次生孔隙是本区最有效、最重要的孔隙类型,而搞清次生孔隙的分布规律及其成因成为下一步有利储层预测的关键。文中综合利用岩心、普通薄片、铸体薄片、扫描电镜及物性参数等资料,对戴南组储层的岩石类型、物性特征、孔隙类型及次生孔隙分布规律进行了综合分析,并从溶蚀作用的发育条件入手探讨了次生孔隙的成因,以期为下一步有利储层预测和勘探开发提供科学依据。研究认为,金湖凹陷戴南组碎屑岩储层主要发育于三角洲、扇三角洲和滨浅湖,受沉积相带控制,储层类型复杂,以不等粒砂岩、含砾不等粒砂岩、细砂岩及粉砂岩为主,不同地区岩性存在差异。根据岩性三角图,砂岩类型以长石岩屑质石英砂岩为主。砂岩成分成熟度中等偏低,结构成熟度中等。戴南组砂岩孔隙度峰值分布在12.0%~14.0%,渗透率峰值分布在1~10 mD。不同沉积环境和地区储层物性也存在一定差异。三角洲前缘亚相的储层物性最好,平均孔隙度约19.4%,平均渗透率约134.2 mD,岩性以细砂岩为主,主要分布于研究区西部和中部。扇三角洲物性次之,平均孔隙度约12.5%,平均渗透率约6.2 mD,岩性以含砾不等粒砂岩为主,位于桐城断裂带东南部便1井附近。滨浅湖亚相的储层物性最差,岩性以粉砂岩为主,平均孔隙度约8.3%,平均渗透率约2.3 mD。戴南组储层孔隙分为原生孔隙和次生孔隙两大类,以次生粒间溶蚀孔隙为主。溶蚀孔隙包括粒间溶孔、粒内溶孔和铸模孔。粒间溶孔多由粒间碳酸盐胶结物如方解石、白云石、铁方解石等溶蚀后形成,粒内溶孔主要是长石及碳酸盐岩屑被选择性溶解而形成,可见白云石晶粒溶解留下的铸模孔。戴南组储层中的原生孔隙相对较少,主要以石英次生加大后的残余粒间孔的形式存在,发育于埋藏较浅的井如新庄1井、关1-1井。戴南组储层孔隙经历了由原生到次生的演化过程。总体上,在浅于约1 100 m,储层主要处于早成岩A阶段,以原生孔隙为主。在1 100~1 500 m,储层处于早成岩B阶段,形成混合孔隙段。超过1 500 m,储层进入中成岩A阶段,原生孔隙消失殆尽,基本上以次生孔隙为主。戴南组储层存在3个次生孔隙发育带:第一次生孔隙发育带在1 200~1 600 m,分布于埋藏相对较浅-中等的井区;第二次生孔隙发育带分布在1 800~2 800 m;第三次生孔隙发育带在2 900~3 000 m左右。第一、二次生孔隙发育带次生孔隙的绝对值较大,说明溶蚀作用较强。戴南组储层次生孔隙发育与方解石、白云石胶结物的溶蚀及长石碎屑和碳酸盐岩岩屑的溶蚀有关。烃源岩成熟排烃是次生孔隙发育的主控因素;碳酸盐胶结物发育提供了次生孔隙发育的物质基础;长石的溶蚀对次生孔隙发育有一定的贡献;次生孔隙的形成与黏土矿物的相互转化有一定的关系;断裂活动进一步促使了次生孔隙的发育。 相似文献
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重力流是自然界中广泛存在的一种流体形式,不同学者基于不同切入点往往会提出多种重力流的划分方案。采用浊流和碎屑流的二分方案,对浊积岩和砂质碎屑流岩的沉积特征展开综述和探讨,旨在进一步概括这2类岩石的沉积特征,明确具有指示意义的最典型相标志。研究表明,在野外露头和钻井岩心中,可以通过以下典型特征鉴别浊积岩和砂质碎屑流岩: 砂岩内若发育以正粒序为特征的递变层理,则应该将其认定为浊积岩;若砂岩内发育泥岩撕裂屑、漂浮状泥砾或不含任何层理构造(块状砂岩),则应该将其认定为砂质碎屑流岩。这些特征是鉴别浊积岩和砂质碎屑流岩最可靠的标志。此外,变形层理、爬升波纹交错层理、波状层理、平行纹层、冲刷侵蚀界面、岩性突变界面和槽模等沉积构造也具有一定指示意义,出现这些特征时需要结合沉积背景、岩相的垂向组合关系和地球物理等资料进行综合判断。 相似文献
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Gravity flow is a widely-distributed fluid type in nature. Various classification schemes of gravity flow are proposed by different researchers from different viewpoints. The scheme of turbidity flow and debris flow is adopted in this paper. The sedimentary characteristics of turbidite and sandy debrite are summarized and discussed to clarify most typical facies marks of these two rock types. The study shows that turbidite and sandy debris can be identified by the following typical characteristics during the outcrop and core observation: If the graded bedding is developed in sandstone,it should be identified as turbidite;if the muddy rip-up clast or no bedding structure(massive sandstone)is developed in sandstone,it should be identified as sandy debris. These characteristics are the most reliable signatures to distinguish turbidite and sandy debris. In addition,some other sedimentary structures such as deformation bedding,climbing ripple cross bedding,wavy bedding,parallel bedding,scouring surface,lithologic abrupt interface,and flute cast also have certain indicative significance. It is necessary to make a comprehensive judgment based on the sedimentary background,vertical combination of lithofacies,geophysics and other materials when these characteristics are presented in the study. 相似文献
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以岩心分析、测井数据为基础,结合薄片鉴定、扫描电镜等分析手段对鄂尔多斯盆地甘泉-富县地区长7致密砂岩储层的岩性、物性以及成岩相进行了研究。长7致密砂岩储层岩性主要以长石砂岩为主,孔隙度主要分布在3%~10%之间,渗透率主要分布在0.05~0.60 mD之间。依据成岩作用类型和强度及成岩矿物组合特征,并结合孔隙发育特征,将研究区内岩相划分为中压实绿泥石薄膜胶结原生粒间孔相、中压实不稳定组分溶蚀溶孔相、强压实弱溶蚀微孔相、强压实伊利石胶结致密相和强压实钙质胶结致密相5类。通过对成岩相较为灵敏的自然伽马和声波时差交汇建立成岩相识别标准,利用"优势相"法绘制研究区成岩相平面图。勘探成果显示,成岩相对致密油富集具有一定控制作用。 相似文献
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The temporal permeability, porosity, and reactive surface area evolution during dissolution of nonfractured/clay-free Fontainebleau sandstone cores was measured using a flow through percolation reactor. Four core dissolution experiments, each of ∼1000 h duration, were performed on sandstone cores having initial porosities ranging from 5.1 to 16.6%. All experiments were performed at 80°C and at far from equilibrium conditions using a 0.1 M NaOH input solution with a calculated in situ pH of 11.4. Permeability evolution was determined using Darcy’s law together with in situ measured differential pressures. Reactive surface area and porosity evolution were quantified from the mass of Si leaving the core during the experiments. The 5.1 and 8.9% initial porosity sandstone cores experienced porosity increases of 1.2 and 1.4 percent, respectively, during the experiments. These cores experienced a corresponding permeability increase from 0.27 to 0.74 mD and 0.57 to 0.87 mD, respectively. In contrast, the 10.6 and 16.6% initial porosity sandstone cores had permeabilities that were essentially constant during the dissolution experiments despite porosity increases of 6.3 and 2.5%, respectively. Only the 5.1% initial porosity core experienced a permeability evolution roughly consistent with a cubic law dependence on porosity. Reactive surface areas increased during the experiments for all cores; those for the 5.1, 10.6, and 16.6% initial porosity cores increased by 21±6% for each percent porosity increase. The reactive surface area of the 8.9% initial porosity core, however, increased by 148% for each percent porosity increase. These results suggest that dissolution of the 8.9% initial porosity core opened a substantial number of isolated pores, exposing new quartz grain surfaces to dissolution. 相似文献
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在油气勘探过程中,对于小位移断层分隔油水封闭能力的控制因素研究尚浅,野外也难以获得不同变形过程的断层带结构及其渗透性变化规律.因此,以高孔隙度纯净砂岩人造岩心为研究对象,采用自主研发的“高压~低速环形剪切装置”开展实验,实验后样品取心分别进行覆压孔渗测试、纳米CT扫描、铸体薄片分析等分析测试.以有效正应力和断层位移为实验变量开展了多组环剪实验,其研究结果表明:宏观上断层面上可观察到明显擦痕与粉末状碎裂岩,微观上确定了断层带内碎裂作用导致的颗粒粒度降低与颗粒的定向排列是孔渗降低的主要原因,断层带渗透率小于10 mD,较母岩降低2~3个数量级.随着断层有效正应力或断层滑动位移增加,断层带碎裂程度增大且粒径和孔径减小,断层带厚度增大,孔隙度和渗透率逐渐减小.这一结果可为小位移断层侧向封闭能力与油气勘探领域的研究奠定理论基础. 相似文献
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野外地质露头为精细刻画沉积体内部结构、建立准确地下地质模型发挥着重要作用。以鄂尔多斯盆地延河剖面长7段为例,采用岩石学、野外露头沉积学方法,详细剖析了湖泊细粒沉积的岩相类型、特征、垂向组合及沉积环境。研究结果表明,延河剖面长7段发育平行层理细砂岩相、流水交错层理细砂岩相、浪成交错层理粉砂岩相、沙纹层理粉砂岩相、变形层理粉砂岩相、水平层理(泥质)粉砂岩相、块状泥岩相、水平层理(砂质)泥岩相、水平纹层页岩相9种岩相类型。在结合区域地质特征基础上,研究认为长7段为远源的曲流河三角洲前缘和浅湖-半深湖沉积,进一步细分出7类沉积单元,其中水下分支河道、支流间湾较为发育,水下天然堤、远砂坝、席状砂发育规模较小,浅湖-半深湖沉积只在长72段下部发育,河口坝基本不发育,仅局部可见。对各沉积单元的垂向分布特征进行深入研究,识别出Ⅰ、Ⅱ、Ⅲ、Ⅳ 4类垂向分布形式,其中Ⅰ、Ⅱ组合主要分布在研究区长71、长73亚段,Ⅲ、Ⅳ组合主要分布在研究区长72亚段。剖面相分析表明,长7沉积期整体为一套先变细、再变粗的细粒沉积序列,为曲流河三角洲前缘沉积—浅湖-半深湖沉积—曲流河三角洲前缘沉积。 相似文献
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渤南洼陷沙四上段油气储层非均质性明显,砂层薄且与泥质间层分布,储层分布规律和空间叠置关系复杂。储层主要受深水盐湖、扇三角洲、滑塌浊积扇、近岸浊积扇、远岸浊积扇五类沉积相控制。利用先进的GridStrat建模软件,采用特殊的"二步建模"处理方法,根据不同沉积相的储层参数分布规律,进行井间插值或随机模拟,建立了沉积相、岩性、孔隙度、渗透率和产能系数模型。沉积相模型显示出扇三角洲及浊积扇是砂体分布的主体,且分布范围广;岩性模型显示出不同岩类的分布受沉积相带、构造位置及不同物源控制。孔、渗模型显示沉积相带和岩性是决定储层孔隙度与渗透率发育程度的主控因素。孔隙度决定了储油气空间的数量,渗透率决定了储层产能系数的大小。产能系数模型显示出产能潜力区为浊积扇和扇三角洲的叠合分布区。研究结论对油田开发部署起到积极指导作用。 相似文献
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鲁武马盆地古近系-新近系发育多套超深水、超大型、富含天然气藏的重力流沉积砂体。以始新统砂体为解剖对象,分析区内重力流砂岩储层特征及成因。结果表明砂体以巨厚层状产出于深海泥岩内部,并与周围泥岩截然接触,测井曲线表现出宏观均一性;岩心揭示此类巨厚砂体是由多期单砂体叠置而成,单砂体是由底部高密度颗粒流和顶部低密度浊流两部分组成,且经历过强底流改造。鲁武马河流三角洲强大物源供给决定了区内砂体分布面积和体积规模;深海滑塌、块体搬运等重力流沉积过程控制了沉积体粒序构造和内部结构;海底区域性强底流持续冲刷并携带走单砂体顶部细粒沉积物,残留了底部“干净”的中粗粒砂岩;多期沉积事件和频繁水道迁移决定了砂体纵、横向叠加展布,并最终形成了区内厚度巨大、岩性宏观均一且连通性极好的超大型深水重力流沉积砂岩储层。 相似文献
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A key challenge in the oil and gas industry is the ability to predict key petrophysical properties such as porosity and permeability. The predictability of such properties is often complicated by the complex nature of geologic materials. This study is aimed at developing models that can estimate permeability in different reservoir sandstone facies types. This has been achieved by integrating geological characterization, regression models and artificial neural network models with porosity as the input data and permeability as the output. The models have been developed, validated and tested using samples from three wells and their predictive accuracy tested by using them to predict the permeability in a fourth well which was excluded from the model development. The results indicate that developing the models on a facies basis provides a better predictive capability and simpler models compared to developing a single model for all the facies combined. The model for the combined facies predicted permeability with a correlation coefficient of 0.41 which is significantly lower than the correlation coefficient of 0.97, 0.93, 0.99, 0.96, 0.96 and 0.85 for the massive coarse-grained sandstones, massive fine-grained sandstones-moderately sorted, massive fine-grained sandstones-poorly sorted, massive very fine-grained sandstones, parallel-laminated sandstones and bioturbated sandstones, respectively. The models proposed in this paper can predict permeability at up to 99% accuracy. The lower correlation coefficient of the bioturbated sandstone facies compared to other facies is attributed to the complex and variable nature of bioturbation activities which controls the petrophysical properties of highly bioturbated rocks. 相似文献
17.
塔里木盆地乌什凹陷白垩系冲积扇—扇三角洲沉积相及有利储盖组合 总被引：1，自引：0，他引：1
通过对乌什凹陷南缘坳陷乌参1井及北缘露头剖面地详细观察,结合测井曲线形态和地震剖面综合分析,乌什凹陷北部和南部由于受构造条件、古气候和物源的影响,发育了截然不同的沉积相类型,北缘露头区以滨浅湖相沉积为主,南部坳陷区则发育了典型的冲积扇—扇三角洲粗粒沉积相。这套沉积碎屑岩颗粒粒度悬殊且不连续,砾岩和砂岩间常显示粒度不连续的现象,剖面中巨厚层砾岩常与中厚层细砂岩、粉砂岩、泥岩沉积层直接接触,无过渡性粒级存在。造成这种现象的主要原因是由于北缘露头区处于相对稳定的构造条件及较远的物源条件,而南缘坳陷区由于靠近温宿凸起物源并受断裂控制。乌什凹陷发育两套较好的储盖组合,分别是亚格列木组—舒善河组中下部砂砾岩与舒善河组泥岩、含膏泥岩和巴什基奇克组—库姆格列木群底砂砾岩与库姆格列木群盐层、含膏泥岩。乌参1井已在第一套储盖组合中的舒善河组中下部的扇三角洲砂体中获得重大发现,这些砂体为扇三角洲前缘的砂坝、辫状河水道充填可形成较好的储层。第二套储盖组合中巴西盖组和巴什基奇克组的砂体分布广泛,岩性较致密;储层厚度较大,纵向发育集中,但物性较差,总体上属于一套中等储盖组合,预测离物源区一定距离应分布有优质储集相带。 相似文献
18.
陆相深水重力流水道的类型细分及其沉积模式是制约其油气勘探开发的重要因素,但研究程度低。通过对鄂尔多斯盆地南缘瑶曲铁路桥剖面三叠系延长组实测、水道形态参数统计及岩相、粒度等分析,开展了湖相重力流水道的沉积特征、沉积过程及沉积模式研究。结果表明:(1)研究区内可识别出4期复合水道,主要为洪水重力流成因。根据其内部单一水道及单砂体形态特征、岩相组成,将其细分为沉积型和过渡型两类。(2)剖面下部2期复合水道为沉积型,以悬浮载荷成因岩相为主,常见块状净细砂岩、薄层泥岩岩相组合和鲍马序列岩相组合;上部2期复合水道为过渡型,岩相以底床载荷与悬浮载荷共存为特征,自下而上以交错层理细砂岩或叠瓦状泥砾细砂岩与含泥砾/泥岩撕裂屑块状细砂岩、平行层理粗粉砂岩及薄层泥岩的岩相组合为特征。(3)结合单一水道规模及其相互关系,建立了区内过渡、沉积型重力流水道的半定量沉积模式。过渡型水道内部侵蚀与沉积作用共存,单一水道宽度小、宽厚比低,呈透镜状,水道间切割性强,砂体横向稳定性较低,表现出不定向叠加、侧向拼接样式;沉积型水道内部由沉积作用主导,单一水道宽度较大、宽厚比较高,呈似板状—透镜状,砂体横向稳定性较高,表现出稳定的垂向加积样式。 相似文献
19.
Relationship of diagenetic chlorite rims to depositional facies in Lower Cretaceous reservoir sandstones of the Scotian Basin 总被引：1，自引：0，他引：1
The relationship between diagenetic chlorite rims and depositional facies in deltaic strata of the Lower Cretaceous Missisauga Formation was investigated using a combination of electron microprobe, bulk geochemistry and X‐ray diffraction data. The succession studied comprises several stacked parasequences. The delta progradational facies association includes: (i) fluvial or distributary channel sandstones (some with tidal influence); (ii) thick‐bedded delta‐front graded beds of sandstone interpreted as resulting from fluvial hyperpycnal flow during floods and storms; and (iii) more distal muddier delta‐front and prodeltaic facies. The transgressive facies association includes lag conglomerate, siderite‐cemented muddy sandstone and mudstone, and bioclastic sandy limestone. Chlorite rims are absent in the fluvial facies and best developed in thick sandstones lacking mudstone baffles. Good quality chlorite rims are well correlated with Ti in bulk geochemistry. Ti is a proxy for Fe availability, principally from the breakdown of abundant detrital ilmenite (FeTiO3). Under conditions of sea floor diagenesis, the abrupt decrease in sedimentation rate at transgressive surfaces caused progressive shallowing of the sulphate‐depletion level and of the overlying Eh‐controlled diagenetic zones, resulting in conditions suitable for diagenetic formation of berthierine to migrate upwards through the packet of reservoir sandstones. This early diagenetic berthierine suppressed silica cementation and later recrystallized to chlorite. Thick euhedral outer chlorite rims were precipitated from formation water in sandstone lacking muddy baffles on this chlorite substrate and inhibited late carbonate cementation. This study thus shows that the preservation of porosity by chlorite rims is a two‐stage process. Rapidly deposited delta‐front turbidite facies create early diagenetic conditions that eventually lead to the formation of chlorite rims, but the best quality chlorite rims are restricted to sandstones with high permeability during burial diagenesis. 相似文献
20.
鄂尔多斯盆地镇北地区长3砂岩的成岩作用及其对储层的影响 总被引：21，自引：0，他引：21
根据砂岩薄片、铸体薄片、扫描电镜、X-衍射分析,研究了鄂尔多斯盆地西峰油田镇北地区长3储层的成岩作用特征,认为该区长3储层处于晚成岩A期阶段,压实作用和胶结作用强烈地破坏了砂岩的原生孔隙结构,溶蚀作用和破裂作用则有效地改善了砂岩的孔隙结构。该区长3储层发育溶蚀作用相、压实作用相、胶结作用相和自生绿泥石胶结残余孔隙相,储层成岩相发育状况决定了孔隙结构的发育特征。发育次生孔隙相和残余孔隙相的砂岩具有较好的孔隙结构,孔渗较高;压实作用相和胶结作用相发育的砂岩具有很差的孔隙结构,孔渗很低。 相似文献