Accumulation Conditions of Organic Matter during the Deposition of Black Shales of the Buxin Formation (Early Paleogene) in the Sanshui Basin, South China

Analyses of organic carbon, nitrogen, sulfur and iron have been performed in order to understand sources and preservation of organic matter in black shale of the Buxin Formation (Early Paleogene) from the Sanshui Basin. The C/N ratios show that the organic matter is characterized by a mixture of terrestrial and phytoplanktonic contributions. The relative importance of different sources depend on climate conditions and most of organic matter is of terrestrial origin. The relationships between C, S and Fe indicate that the brackish environment with alternation of anoxia and low-O2 developed in the bottom waters during the deposition of these organic-rich sediments as a result of a mixed setting of thermal stratification and salinity stratification, the latter being the consequence of intermittent sea water incursion. Bacterial sulfate reduction is the most effective early diagenesis affecting the preservation of organic matter. The intensity of sulfate reduction is related to the relative proportion of metabolizable organic matter supplied to sediments.

Occurrence of Highly Mature Organic Matter in Marine Black Shale Petroleum Source Rocks of Basal Cambrian from Northern Tarim Basin, China

More and more evidence indicates that organic matter (OM) in immature organic-rich sediments and sedimentary rocks is chemically adsorbed onto the outer surfaces of minerals and into interlayer (inner) surfaces of smectitic clay minerals in the form of amorphous molecular-scale carbon. But there have been few reports about the occurrence of highly mature OM in marine black shales (petroleum source rocks). The occurrence of highly mature OM in the black shales of basal Cambrian from northern Tarim Basin is studied in this paper. Based on the comprehensive analyses of total organic carbon contents (TOC), maximum thermolysis temperatures (T-max) of OM, mineral surface areas (MSA), and scanning electronic microscopic (SEM) and transmission electronic microscopic (TEM) observations of the black shales, it is concluded that the highly mature OM in the marine black shales of the basal Cambrian from northern Tarim Basin occurs in particulates ranging in size from 1 to 5 μm in diameter. Through the contrast of the occurrence of the highly mature OM in the black shales with that of the immature ones in modern marine continental margin sediments, some scientific problems are proposed, which are worth to study further in detail.

Geochemistry of lower Silurian shale of Longmaxi Formation,southeastern Sichuan Basin,China:Implications for provenance and source weathering

Lower Silurian Longmaxi Shale(SLS) in southeastern Sichuan Basin, China, was analyzed for major and selected trace elements, and their provenance, intensity of palaeoweathering of the source rocks were analyzed based on these elements. The results show that SiO_2, Al_2O_3 and Fe_2O_3, are dominant major elements with average contents of 60.59%, 15.91% and 5.87% in Upper Silurian Longmaxi Shale(USLS), and 65.14%, 13.24% and 4.68% in Lower Silurian Longmaxi Shale(LSLS). The TiO_2-Zr plot, Hf(ppm) versus La/Th discriminant diagram, and abundance of Cr and Ni suggest a dominantly felsic source for the Longmaxi sediments. Average chemical index of alteration(CIA), plagioclase index of alteration(PIA) values(64.05% and 72.86%, respectively) imply low-degree chemical weathering of the source material in early Longmaxi time, and average CIA, PIA values(68.44% and 80.35%, respectively) imply moderate chemical weathering of the source material in late Longmaxi time.

Shallow-Water Origin of a Devonian Black Shale, Cleveland Shale Member (Ohio Shale), Northeastern Ohio, USA

Black shales are usually interpreted to require anoxic bottom waters and deeper water sedimentation. There has long been a debate about whether the Devonian Cleveland Shale Member of the Ohio Shale (CSM) was deposited in shallow- or deep-water depositional environments. This study looked at the CSM at 3 stratigraphic sections and 5 well cores in northeastern Ohio. The CSM mostly consists of sapropelite (interbedded carbonaceous black mudstones and gray calcareous claystones). The black and gray “shales” are rhythmically bedded at micro- (<1 cm thick), meso- (<10 cm thick) and macro-scales (10s of cm thick) and represent changes in organic matter content (ranging from 7% - 20% TOC). Three types of event layers are interbedded with the mudrocks: 1) tempestites, 2) proximal turbidites, and 3) hyperpycnites. Individual tempestites and turbidites are laterally continuous?≥35 km, while hyperpycnites are too thin (<1 cm) to trace laterally. Tempestites consist of hummocky stratified sandstones with groove casts and escape burrows overlain by planar laminated sandstones with wave ripples at the top. Tempestites average 13 cm thick, but can be amalgamated up to 45 cm thick, and are more common in the lower half of the unit. Turbidites are incomplete Bouma sequences that average 6 cm thick, show evidence of combined flow (“wave-modified turbidites”), and are more common toward the top of the unit. Hyperpycnites (density underflows from river discharge) consist of inverse-to-normal graded sandy or silty microlaminae that have been studied primarily by using petrography and SEM. Condensed sections in the CSM are probable firmgrounds with carbonate concretions, and indicate intervals of low sedimentation rates. The evidence shows that the CSM depositional environment was receiving siliciclastics from the northeast (e.g., Catskill delta), and that the coarser-grained clastic sediment was primarily transported as density underflows (turbidites and hyperpycnites). However, significant storm deposits (tempestites) within the CSM indicate erosion and redeposition occurred on a muddy clastic marine shelf at paleo-water depths less than storm-weather wave base (probably?≤50 m depth).

川东北地区陡山沱组页岩地球化学特征与古环境分析

下震旦统陡山沱组页岩是四川盆地震旦系成藏的主要烃源岩,是近年来海相古老地层天然气勘探的重点层位。根据川东北城口地区白包溪、柿坪两个剖面的46件样品的有机地球化学(总有机碳、岩石热解、干酪根碳同位素)和元素地球化学(主微量元素、稀土元素)特征,分析了陡二段和陡四段烃源岩的地球化学特征与沉积环境的变化情况。结果表明,该地区陡山沱组页岩有机质丰度高,总有机碳(TOC)含量在0.19%~20.38%(均值4.76%),有机质类型为Ⅰ型干酪根,成熟度已达到过成熟;黑色页岩较高的δEu异常值与异常富集V、Mn、Mo、Ba和U微量元素,揭示了该时期强烈的热液作用;稀土元素配分模式与氧化还原指标识别出川东北地区陡二段沉积时期水体在缺氧-贫氧-硫化的水体条件下反复波动,陡四段水体环境则由贫氧演变为缺氧-硫化环境,总体盆地环境水体连通性较强,沉积速率较高,上升流携带热液来源的营养元素造成了生产力的繁盛,促进了有机质页岩的形成。

Lithofacies paleogeography and exploration significance of Sinian Doushantuo depositional stage in the middle-upper Yangtze region, Sichuan Basin, SW China

In recent years, natural gas exploration in the Sinian Dengying Formation and shale gas exploration in Doushantuo Formation have made major breakthroughs in the Sichuan Basin and its adjacent areas. However, the sedimentary background of the Doushantuo Formation hasn't been studied systematically. The lithofacies paleogeographic pattern, sedimentary environment, sedimentary evolution and distribution of source rocks during the depositional stage of Doushantuo Formation were systematically analyzed by using a large amount of outcrop data, and a small amount of drilling and seismic data.(1) The sedimentary sequence and stratigraphic distribution of the Sinian Doushantuo Formation in the middle-upper Yangtze region were controlled by paleouplifts and marginal sags. The Doushantuo Formation in the paleouplift region was overlayed with thin thickness, including shore facies, mixed continental shelf facies and atypical carbonate platform facies. The marginal sag had complete strata and large thickness, and developed deep water shelf facies and restricted basin facies.(2) The Doushantuo Formation is divided into four members from bottom to top, and the sedimentary sequence is a complete sedimentary cycle of transgression–high position–regression. The first member is atypical carbonate gentle slope deposit in the early stage of the transgression, the second member is shore-mixed shelf deposit in the extensive transgression period, and the third member is atypical restricted–open sea platform deposit of the high position of the transgression.(3) The second member has organic-rich black shale developed with stable distribution and large thickness, which is an important source rock interval and major shale gas interval. The third member is characterized by microbial carbonate rock and has good storage conditions which is conducive to the accumulation of natural gas, phosphate and other mineral resources, so it is a new area worthy of attention. The Qinling trough and western Hubei trough are favorable areas for exploration of natural gas(including shale gas) and mineral resources such as phosphate and manganese ore.

川南地区上奥陶统—下志留统五峰组—龙马溪组快速海进页岩特征及有机质分布

快速海进页岩的特征及形成机理是细粒储层地质学研究的重点之一。地震层位追踪、连井地层对比、X衍射全岩分析、总有机碳测试和场发射扫描电镜分析表明,川南地区五峰组—龙马溪组快速海进页岩位于龙马溪组最底部,对应于笔石带LM1。该页岩石英平均含量49.3%(其中黏土级石英含量85%),方解石平均含量10.5%,白云石平均含量8.4%,黏土矿物平均含量23.4%。向盆地方向,石英含量增加,黏土矿物含量降低。快速海进页岩形成于相对海平面快速上升阶段,页岩厚度0.5~2.8 m,由盆地边缘向盆地中心逐渐增厚。页岩平均TOC含量5.4%,由盆缘向盆地中心逐渐降低,纵向TOC含量剖面呈现4种叠置样式。该套页岩的矿物组成和厚度分布与沉积时期的快速海进、生物及火山作用密切相关。快速海进导致陆源供给减少,故页岩厚度较小;生物及火山作用导致页岩以微晶石英为主,盆地中心厚度较大。该套页岩的高TOC含量与水体缺氧、低沉降速率和高初级生产力有关。水体缺氧导致有机质保存能力增强,低沉积速率可减弱有机质的稀释,而初级生产力高可增加有机质的供给。该套页岩TOC含量平面变化及叠置样式与水深有关。随着水深增加,有机质沉降过程中的降解和再循环增加,故TOC含量降低。同时,随着水深增加,沉积物可容空间增大,从而形成不同的TOC含量叠置样式。

松辽盆地青山口组页岩沉积水体环境演变的古生物学证据

松辽盆地古龙页岩油勘探开发目的层和有利区优选对页岩沉积水体环境恢复提出了新要求。以古生物群落作为古湖泊水体环境演变的示踪指标,对古页8HC井白垩系青山口组古生物组合(包括鱼、叶肢介、介形类、藻类)进行了系统分析。研究发现,满洲鱼和叶肢介仅出现在Q7油层,丰度高但属种单一;介形类在Q7—Q9油层的种属数目和丰度相较于Q1—Q6油层均显著增加;沟鞭藻丰度在Q1,Q2和Q7油层存在3个峰值。古生物组合指示松辽盆地青山口组沉积期整体为淡水-微咸水的古湖泊环境;Q7油层中生物多样性的显著增加和沟鞭藻的峰值丰度,则指示比较明确的海侵事件;Q1和Q2油层的沟鞭藻峰值丰度可能指示了湖平面上升初期的海侵事件。通过与现代马拉开波湖的对比,提出松辽盆地青山口组沉积期虽出现了海洋生物,但海侵可能只是在独特古地理位置和气候背景下的暂时性或偶发性湖-海连通,并未显著改变松辽古湖泊整体的水体属性和生态组成。

川东北地区页岩气地质条件及其勘探潜力——以峰探1井上二叠统吴家坪组为例

四川盆地上二叠统吴家坪组沉积相横向变化大,川北地区发育一套海相黑色页岩。以川东北峰探1井为研究对象,通过岩石学、地球化学分析、扫描电镜、低温氮气吸附和甲烷吸附等方法,对页岩气地质条件进行研究。研究结果表明:①在川东北地区吴家坪组发育两套黑色页岩,吴二段发育一套滨岸潮坪相黏土质灰黑—黑色页岩,脆性指数低,可压裂性弱;吴三段发育一套深水陆棚相黑色硅质、钙质页岩,脆性指数高,可压裂性强。②吴二段页岩有机质丰度平均值为1.41%,黑色页岩厚度较薄,有机碳含量大于2%,有机质类型为Ⅲ型;吴三段页岩有机质丰度平均值为3.52%,黑色页岩厚度26 m,有机碳含量大于2%,有机质类型为Ⅱ1—Ⅱ2型,均达到过成熟阶段。③吴家坪组二段页岩储集空间主要以黏土矿物之间粒间孔和微裂缝为主,有机质孔相对不发育,孔隙体积0.0066 cm3/g,以介孔为主、微孔次之,含气性为1.5190 cm3/g;吴家坪组三段页岩储集空间主要以有机质孔为主,孔隙体积平均为0.0141cm3/g,孔隙以微孔为主、介孔次之,含气性平均为2.3070 cm3/g,孔隙结构和含气性受有机质丰度控制明显,矿物组分对其没有明显控制作用。④吴二段页岩气地质条件相对较差,页岩气资源勘探潜力较弱;吴三段页岩气地质条件较好,含气性和有机质丰度优于下志留统龙马溪组,显示良好的页岩气勘探潜力。

Biostratigraphic correlation of the Ordovician black shales in Tarim Basin and its peripheral regions

Ordovician black shales are widely distributed in the Tarim Basin and its peripheral regions,and some of them may serve as potential hydrocarbon source rocks.The present study of the Ordovician graptolite fauna from these shales,together with the yielded conodonts and chitinozoans etc.,permits a refined correlation of the rocks.Based mainly on a new collecting of the graptolites and a study of the faunas in Kalpin and Kuruktag regions,and the successful identification of the new graptolite material from a few drill cores within the basin,we are able to update our knowledge of the Ordovician in the regions,and draw some conclusions:(1) The most widespread distribution of the black shales in the Tarim Basin and its peripheral regions,which correspond to the Nemagraptus gracilis Zone,may be related to a global sea-level rise during this time interval.(2) Black shales of Ordovician occur most frequently and extensively in the Kuruktag(also spelled as Quruq Tagh) region in east-ern Tianshan Mountains,spanning Tremadocian to mid-Katian(D.spiniferus Zone) temporally and extending southeastwards into Manjiaer Depression.The black shales of the D.spiniferus Zone may even extend into the central Tarim Basin.(3) Three different bio-and litho-facies belts(Bachu:carbonate platform and reef belt;Kalpin-Aksu:marginal platform and upper slope belt;Wushi:slope belt) are recognized in the northwestern Tarim Basin.(4) The internationally well-correlated Saergan black shale,which has been considered to possess high potential for hydrocarbon source rock,may possess a restricted distribution in the Kalpin and Aksu areas.

Geochemistry of black shale at the bottom of the Lower Cambrian in Tarim Basin and its significance for lithosphere evolution

The systematic analyses of trace elements, REEs and PGEs of black shale at the bot-tom of the Lower Cambrian in Tarim Basin have been made for the first time in this work. The basic geochemical features are that some trace elements having something to do with the deep-level fluids are highly enriched, including V, Cr, Ni, Cu, Zn, Ge, As, Sr, Y, Mo, Ag, Cd, Sb, Ba, Pb and U, and the Th/U and Th/Sc ratios decreased compared with those in the same kind of rocks in the crust, that the enriched degrees of LREEs are reduced, Eu and Ce depleted distinctly in the chon-drite-normalized REE patterns, and that the contents of PGEs and Au are increased. These char-acteristics indicate that there were more mafic interior sources in the basin when the black shale was deposited. Generally, the interior sources show an extensional tectonic setting of lithosphere. It can be seen from the change of the characteristics of trace elements, REEs and PGEs along the black shale section that the quantity of interior source from inner earth is gradually increased upwards in the lower part of the section, reaches the peak value as shown by sample No. 4 (XCM7-1), and then decreased, which might indicate the episodic extension of lithosphere in the beginning of the Lower Cambrian.

黔东北大塘坡组菱锰矿矿床控矿因素研究

黔东北黑色泥岩盆地中菱锰矿的品位普遍偏低,高品位的块状菱锰矿在横向上和垂向上并非稳定存在,弄清菱锰矿的空间分布规律可以为勘探开发提供指导。文章首先从区域尺度分析了菱锰矿矿床分布与黑色泥岩盆地内部次级洼陷的关系,然后以杨家湾锰矿床为例,分析了同一次级洼陷内锰品位与含锰岩系厚度和矿层厚度的相关性。最后选取次级洼陷内的典型探井,从矿石的结构特征和矿物共生组合规律等微观尺度,研究了菱锰矿矿床的垂向非均质性,探讨了黑色泥岩盆地中菱锰矿富集的控制因素。研究表明,菱锰矿主要赋存于有机质含量较高的大塘坡组一段底部,锰矿品位与矿层厚度呈正相关,高品位的锰矿主要为泥晶结构的块状菱锰矿,平面上主要分布于黑色泥岩盆地的次级洼陷沉积中心;锰矿层在横向上并非稳定的均质沉积,从洼陷中心到洼陷边缘,菱锰矿的品位逐渐降低;锰矿层与粉砂质泥页岩交互沉积,具有很强的垂向非均质性。

黑色岩系型矿床的形成作用及其在我国的产出特征

黑色岩系作为地史上反复出现的时限沉积相 ,反映了环境的突变及环境事件 ,构成了许多重要矿床的赋矿岩系。我国共有 2 5种以上的有用元素和组份的聚集成矿与黑色岩系有关 ,它们呈自然金属、硫化物、氧化物、碳酸盐、硫酸盐、磷酸盐等十余种形式产出。黑色岩系型矿床一般规模较大 ,我国南方赋存大—超大规模矿床的黑色岩系分布于 9个纪级单位的 13个含矿层位中 ,共形成了 4个超大型矿床和 6个大—中型矿床密集成矿区。根据盆地流体在黑色岩系型矿床成矿演化的阶段性 ,可以将其矿床的形成划分为 :沉积期和成岩期。前者可形成大—超大型锰、磷、重晶石矿床 ,成岩期可能形成大—超大型金、银、铅锌、锑、锡多金属矿床。

松辽盆地白垩系青山口组黑色页岩的形成环境及海水侵入的底流模式

通过对中央坳陷区两口钻井剖面和东南隆起区野外露头剖面的沉积学、矿物学和地球化学研究，认为松辽盆地白垩系青山口组黑色页岩形成于稳定分层的湖相环境；周期性海水注入形成的底流是导致水体分层和黑色页岩沉积的重要因素。

塔里木盆地北部下寒武统底部黑色页岩形成的次氧化条件

富有机质黑色页岩的形成长期以来被认为是缺氧沉积环境的证据,并被作为全球缺氧事件的标志。塔里木盆地下寒武统底部黑色页岩的岩石学特征说明其沉积在受陆源有一定影响的陆棚环境中。矿物学研究表明,硫均以硫酸盐状态存在,没有见到黄铁矿,说明其形成在硫酸盐还原带以上。黑色页岩中结核状氟磷灰石的存在以及剖面底部结核状磷块岩的出现,表明了一种与现代热带太平洋东海岸和阿拉伯海相类似的广泛发育上升洋流的大陆边缘沉积环境。黑色页岩的地球化学特征中,Re和Mo的高度富集、高的Re/Mo比以及含有一定量的Mn,Cd和U的相对富集以及低的Cd/U比等,这些特点均支持了黑色页岩沉积于次氧化条件的认识。

应用ICP-MS研究川西南龙马溪组泥页岩稀土元素特征及沉积环境

为深入研究盐源盆地龙马溪组黑色岩系的沉积环境、构造背景及物源属性,指导区域页岩气勘探及相关研究,本文利用电感耦合等离子体质谱技术研究了盐源盆地南缘龙马溪组黑色页岩的稀土元素地球化学特征和沉积环境。结果表明:该区稀土总量偏低,轻稀土富集重稀土亏损,轻重稀土分异较大;δCe_N均值为0.87,显示弱的负异常,δEu_N值为0.66~1.43,变化范围较大,说明源岩成分复杂;La_S/Yb_S均值为1.31,说明研究区构造背景主要为被动大陆边缘,源岩为古老沉积岩、花岗岩及中基性岩的混合物,推测康滇古陆为其提供了主要物源。δCe_S为负异常,δEu_S为正异常,La/Ce<1等特征均指示沉积期水体为还原环境,推测为深水陆棚沉积,且受到一定程度热水沉积影响。深海热液带来丰富的营养元素有利于有机质形成,还原水体环境有利于有机质保存,使得研究区龙马溪组泥岩页富含有机质,且富有机质页岩段厚度较大,由此初步认为龙马溪组泥页岩为优质烃源岩储层。

三水盆地古近系(土布)心组黑色页岩中黄铁矿的形成及其控制因素

黄铁矿是富有机质沉积的特征矿物。根据TOC/S、TOC/DOP、S/Fe关系以及S-TOC-Fe多重线性回归分析结果对三水盆地古近系土布心组红岗段黑色页岩中沉积黄铁矿的形成及其控制因素进行了分析。土布心组红岗段黑色页岩的黄铁矿有成岩黄铁矿和同生黄铁矿两种成因组分。红岗段下部(亚段A)有机碳含量普遍较低,底部水体以弱氧化条件为主,硫酸盐还原作用发生于沉积物/水界面以下,黄铁矿为成岩成因,其形成主要受有机质的限制。红岗段中上部(亚段B和C)的沉积条件变化频繁,其有机碳含量变化幅度大。富有机质(TOC>4%)岩层形成于缺氧的底部水体条件下。水体中可含H2S,碎屑铁矿物在埋藏之前即与之在水体中反应形成同生黄铁矿。这一过程不受有机质的限制,而是受活性铁与H2S接触时间的限制。同时,由于大量淡水输入导致硫酸盐浓度的降低,从而对硫化物形成有一定的限制作用。对于低有机质(TOC<4%)样品,黄铁矿由同生和成岩组分组成。其中以成岩黄铁矿为主,其形成过程主要受有机质限制,而同生黄铁矿受铁矿物与H2S接触时间的限制。

塔里木盆地西北缘白垩纪大洋缺氧事件(OAE_2)

大洋缺氧事件(OAEs)关系到碳-氧循环、古海洋-古气候变化等一系列重大科学问题。本文通过对塔里木盆地西北缘乌恰地区库孜贡苏剖面白垩系地层的沉积和生物特征以及沉积物色度、有机质和碳氧同位素指标的研究,结合前人研究成果,论证并证实该区上白垩统库克拜组存在大洋缺氧事件(0AE_2),并认为该区这次海洋缺氧条件可能存在四次(分别为OAE_(2a)、OAE_(2b)、OAE_(2c)和OAE_(2d)),它与我国西藏南部地区的OAE_2事件构成白垩纪Cenomanian-Turonian时期特提斯海伸向我国的南北两个分支,这次大洋缺氧事件可能与同期全球海平面大幅度上升有关。这对丰富我国白垩纪事件研究、查清白垩纪新特提斯洋演化以及塔里木盆地白垩纪古环境和烃源岩大规模形成等具重要意义。

江西修武盆地下寒武统黑色页岩矿物成分特征及意义

以江西修武盆地下寒武统王音铺组、观音堂组黑色页岩为研究对象,通过对野外剖面样品和钻井取心样品定性和定量分析,研究修武盆地下寒武统页岩气储层矿物成分特征,结果表明,王音铺组、观音堂组黑色页岩矿物成分以黏土矿物和石英为主,石英的平均质量分数为58.63%,黏土矿物平均为25.4%。其次为方解石,平均为51.46%,另外还含有较高的长石和黄铁矿,平均质量分数分别为2.5%和4.68%。其余矿物如方解石、白云石、(硬)石膏等含量较少,平均质量分数<5%。这种矿物成分组成与Barnett页岩及龙马溪组页岩既有相似性,又有差异性。修武盆地下寒武统页岩矿物组分所反映的沉积环境、有机质演化及黑色页岩储集意义表明,该套页岩石英的质量分数>50%的泥(页)岩厚度接近50m,是理想的页岩气勘探开发层位。

辽河西部凹陷页岩纹层结构及其储集空间意义

几乎所有的富有机质页岩均不同程度地包含了纹层结构,对应反映了不同的沉积相产物、页岩有机质丰度、生烃能力、储集空间及含气性等特点。按照陆相断陷盆地富有机质页岩的沉积特点并依据有机质分布的连续性差异,将辽河西部凹陷黑色页岩结构划分为连续型、断续型和分散型3种纹层结构。借助岩心观察、薄片分析、扫描电镜等手段,结合统计学研究,对辽河西部凹陷黑色页岩纹层结构进行了研究。沙四段黑色页岩主要形成于半咸水的半深湖相,发育了灰云质型弯曲状连续型纹层和黏土型平直状连续型纹层;沙三段黑色页岩主要为深湖—半深湖相长英质断续型纹层和分散状纹层。连续型碳酸盐混合纹层页岩既可以与化学作用有关,也可以与藻类勃发产生的生物化学作用有关,或者是二者的共同作用。富有机质黏土连续型页岩,主要为气候变化所形成的季节性纹层(生物作用)。断续型纹层通常由黏土纹层有韵律组合,粉砂、黏土则是以平流或层间流的方式季节性输入(机械作用)。页岩纹层形态在很大程度上决定了页岩的生烃能力和生烃特点,进而可能影响储集能力。连续型纹层结构(白云质泥岩)碳酸盐含量高,易发生溶蚀作用,有机质丰度高、生烃能力强,有机孔发育,有机孔—微缝储集空间系统造成含油气性好,且碳酸盐含量与含油气性正相关。断续纹层除发育各种无机孔外,还发育有机孔、沿层理裂缝和矿物解理裂缝,从而导致页岩储集空间发育,页岩含气性条件优越。分散型(块状泥岩)储集空间相对不发育,含气性条件较差。