宁夏固原炭山油页岩矿床的主要特征及开发利用前景

油页岩作为非常规新能源之一,已经受到人们的广泛关注,是目前油气领域里的研究热点。前人及我们最近的研究结果表明：宁夏固原炭山地区存在大量的与煤伴生的油页岩资源。油页岩赋存于中侏罗统延安组之中。成矿环境为内陆湖泊环境。矿区构造为一中度弯曲的复式褶皱,两翼产状角度20°～30°。以纵向正断层为主。油页岩呈层状,有一定规模的油页岩一般分布于煤层的上部或底部;油页岩共8层,总厚度14.4m,含油率为2.7%～11%,发热量2.88～20.98MJ/kg,视比重1.55～2.46,灰分34.30%～83.68%。其中,煤19灰分大于40%,但含油率大于7%,被前人称之为炼油用煤。炭山油页岩宏观上呈黑色,略具油脂光泽。片状、层状构造,参差状、贝壳状断口。硬度小,条痕亮褐色,油脂光泽明显。油页岩矿石和页岩油边际经济的资源量分别为40301万吨、3718.3万吨,达中型规模,目前其经济价值至少在483亿元以上。炭山油页岩含油率高,品质好,资源量级别高,埋藏浅,交通条件好,并且现在已有煤矿正在采煤,可考虑与其联合开发和利用。     

柴达木盆地西部古近系干柴沟组页岩储层特征

岩心观察和岩石薄片鉴定显示,柴达木盆地西部古近系干柴沟组存在层状-非层状泥页岩、层状-非层状灰质泥页岩、泥灰岩、层状-非层状粉砂质泥岩和泥质粉砂岩5种岩相。总有机质含量（TOC）为0.2%~1.4%,有机质以Ⅱ型干酪根为主,普遍处于成熟阶段。泥页岩矿物成分以碎屑石英和粘土矿物为主,并含有不等量的方解石、白云石、长石、黄铁矿等;发育原生孔隙、有机质生烃形成的孔隙、次生溶蚀孔隙、粘土矿物伊利石化体积缩小形成的微孔隙及微裂缝5种页岩气储集空间类型。研究表明,储集空间发育主要受岩相类型、矿物成分、成岩作用、有机碳含量和有机质成熟度的影响。虽然研究区泥页岩中有机质含量普遍较低,但有机质普遍处于成熟阶段,储层中发育多种储集空间类型,并富含脆性矿物和富伊利石的粘土矿物。因此,柴达木盆地西部干柴沟组泥页岩为良好的页岩气储集层,具有一定的页岩气勘探前景。     

岩相古地理研究可作为页岩气地质调查之指南

得益于水平井和压裂技术的发展,页岩气已成为中国油气勘探开发的热点。沉积环境决定了有机质的含量、类型、矿物组成和含量、厚度、埋深等页岩气基本地质要素的特征。在开展区域沉积相研究的基础上,通过岩相古地理编图方法,可以明确烃源岩有利相带的时空分布,从而为页岩气勘探提供基础和方向。以四川盆地南部及邻区志留系龙马溪组为例,通过详细的沉积相及岩相古地理研究,确定了烃源岩的有利相带和空间展布特征。在岩相古地理图的基础上,叠加矿物组成、有机碳含量、成熟度、厚度等页岩气评价参数,预测了四川盆地南部及邻区志留系龙马溪组页岩气远景区和有利区。页岩气地质调查的根本目标是寻找页岩气的远景区和有利区,为页岩气勘探开发提供科学依据。因此,岩相古地理研究与编图可作为基本方法及关键的技术,为页岩气的地质调查工作提供指南。     

鄂尔多斯盆地南缘延长组长7油页岩地球化学特征及其地质意义

微量、稀土元素和有机地球化学参数对于揭示油页岩沉积环境、古气候等沉积成矿作用、预测油气、油页岩资源潜力具有重要意义。对鄂尔多斯盆地南部延长组长7油页岩获得的地球化学参数进行研究,油页岩微量元素与地壳平均值及其他地区油页岩相比,W、Mo、As、Sb、U等元素明显富集,Sc、Cr、Ni、Cl等元素明显亏损。油页岩稀土元素总量较低,轻稀土元素富集,重稀土元素亏损,稀土元素较球粒陨石发生了明显分异,较北美页岩分异不明显。油页岩有机质类型为Ⅰ型和Ⅱ_1型,以Ⅱ_1型为主,有机质丰度达到最好级,成熟度为低成熟-成熟。通过对这些地球化学参数及特征的进一步分析,获得以下认识:1长7油页岩是在温暖潮湿的气候条件下,形成于陆相淡水深湖-半深湖还原环境中,这种沉积环境有利于油页岩有机质的富集和保存;2本区不具备形成油气田的潜力,具备形成中-高品级的特大型油页岩矿床的潜力。     

下辽河盆地东部凹陷古近系沙河街组页岩气成藏条件分析及资源量计算

在分析录井、钻井及地球化学等资料的基础上,对辽河盆地东部凹陷沙河街组页岩气成藏地质条件进行研究。东部凹陷沙河街组富有机质泥岩主要为沉积于半深湖-深湖的暗色泥岩及发育在沼泽环境中的炭质泥岩,分布面积为3 000 km~2,有机碳丰度为1%~16.97%,干酪根类型以Ⅱ_1和Ⅱ_2型为主,其有机质镜质体反射率(Ro)整体处于低成熟-高成熟阶段。通过类比美国五大页岩气产区成藏地质条件,笔者预测东部凹陷驾掌寺—二界沟、黄于热地区可评为有利页岩气远景区。利用气测全烃值、孔隙度及吸附气计算总含气量,求得有利远景区在沙三段与沙一、二段页岩气资源量分别为871×10~8m~3和742×10~8m~3。     

松辽盆地东南隆起区增深3井上白垩统青山口组油页岩特征

为近一步了解松辽盆地东南隆起区上白垩统青山口组油页岩特征,对该地区新钻井增深3井青山口组全取芯井段进行了详细的岩芯观察、取样与测试等单井分析。结果表明:研究区增深3井青山口组共发育5层油页岩,主要形成于半深-深湖沉积环境,油页岩单层最厚达5 m;含油率为3.50%~7.34%,平均为4.73%;发热量分布范围为1 928.68~4 537.08 J/g,平均为2 691.42 J/g;灰分含量为82.65%~87.56%,平均为85.02%;全硫含量为0.59%~4.08%,平均为1.40%,为高灰分、低发热量、低硫、中--低品质油页岩。其中含油率与发热量、有机碳含量呈明显的正相关性,与灰分含量呈明显的负相关性,表明发热量、有机碳和灰分含量可作为油页岩含油率良好的替代指标。对油页岩段的测井曲线分析显示,油页岩层较泥岩具有高声波时差、高电阻率、低密度的特征,可作为识别油页岩的辅助标志。通过对样品岩石热解参数进行分析,表明油页岩中的有机质类型主要为Ⅰ型,其次为Ⅱ型,有机质成熟度处于未熟-低熟阶段。     

沉积环境对页岩气储层的控制作用——以渝东北地区五峰组-龙马溪组为例

以"沉积控相,相控储层"为研究思路,基于野外露头剖面实测与室内实验测试,以及前人的研究成果,探讨渝东北地区上奥陶统五峰组-下志留统龙马溪组沉积环境对页岩气储层的控制作用。研究表明,渝东北地区五峰组-龙马溪组富有机质泥页岩主要发育于滞留浅海陆棚相中,沉积中心页岩厚度可达70~80m,有机碳含量(TOC)最高可达7.56%,平均3.09%。静水缺氧还原沉积环境岩石类型主要以富含有机质的含碳质含粉砂泥(页)岩、含碳质含硅质泥(页)岩、含硅质泥(页)岩、含碳质泥(页)岩、含粉砂泥(页)岩及硅质泥(页)岩为主。页岩矿物成分以石英(平均达62.76%)和黏土矿物(平均达22.61%)为主。缺氧还原环境下沉积的大量黄铁矿形成的黄铁矿晶间孔、黏土矿物层间微孔隙、有机质生烃形成的微孔隙以及脆性矿物控制形成的微裂缝为页岩气提供了良好的储集空间。沉积环境控制的储层发育特征的研究可为页岩展布、有机质丰度、储集空间及其之后有利区评价等研究提供基础。     

Gcochemical characteristics and the (Ecological significance of oil shales from the youganwo formation,maoniing basin. China北大核心CSCD

Geochemical elements of oil shale in the Maoniing Basin were analyzed to discuss provenance attribute and depositional environment of the Youganwo formation. Experimental date of the major elements, trace elements and rare earth elements of 24 samples from the Maoye I well were examined. The analyzed oil shale samples were characterized by enrichment of Tb, U, Kb and LREE, depleted of Zr, Cr and Hf, negative Eu and Ce anomalies, indicating that these samples were originated from continental crust. The chemical index of alteration( CIA) values and the ZrZSc-Th/Sc diagrams indicate that source rooks had undergone intense chemical weathering and deposition recirculation. Based on the La/Th-Hf and La/Yb-^REE diagrams and the negative anomaly of Eu element, the oil shale in the Maoniing Basin has diverse sources, which mainly came from felsic source region of the upper crust or the mixture of felsic volcanic rocks, granite and sedimentary rocks. Ratios of the SrZCu, MgO/CaO suggest that oil shale was formed in fresh water under warm and humid climate, shallow water column became deeper during the middle and late sedimentary period. The depositional environment is interpreted to be limnetic with weak reduction at the early stage and gradually turned into semi-deep to deep lacustrine.     

新疆北部吉木乃坳陷下二叠统卡拉岗组页岩气地质特征初探

为评价新疆北部吉木乃坳陷页岩气勘探潜力,通过对吉木乃坳陷下二叠统卡拉岗组暗色页岩段有机地球化学以及储层特征分析,初步探讨其页岩气地质特征。卡拉岗组下段暗色页岩段烃源岩以碳质泥页岩为主,TOC最小值为0.3%,最大值为4.32%,平均值为1.01%。有机质丰度中等,有机质类型为Ⅲ型,Ro值介于1.43%~2.87%之间,平均值为2.12%。热演化程度为成熟-过成熟度阶段,具较好天然气生成能力。暗色页岩矿物成分以石英、长石等脆性矿物为主,粘土质矿物次之,具较好可裂性及吸附性。页岩孔隙以宏孔、细小孔以及小孔为主,储集空间主要为粒内及粒间溶孔、矿物间的微孔隙与微缝隙、矿物微裂缝。孔隙度为0.97%~1.52%,平均为1.36%。渗透率为0.0097~0.0197m D,平均为0.0139m D,具较好天然气储集能力。     

A possible shale gas prospect? First results of the organic composition and thermal maturity of the Carboniferous Namoi Formation,northern NSW,Australia

The Namoi Formation in the Werrie Syncline, north and west of Tamworth, is part of the well-preserved Devonian–Carboniferous fore arc in the New England Fold Belt. The formation is between 640–914 m thick and consists of dominant olive-green mudstones with lenses of sandstone and oolitic limestone. To assess shale gas prospectivity, we analysed five outcrop samples from the Namoi Formation in the Keepit area. Well-preserved aliphatic and aromatic hydrocarbon fractions do not show evidence of weathering or biodegradation. n-Alkanes in all samples have a unimodal distribution maximising at C₂₆ to C₂₈. Little odd-to-even n-alkane carbon number predominance and relatively low Pr/n-C₁₇ and Ph/n-C₁₈ ratios are consistent with a high thermal maturity. Based on the distribution of alkylnaphthalenes and alkylphenanthrenes, the Namoi Formation is in the gas window. Calibration of the methylphenanthrene index and ratio with vitrinite reflectance suggests a calculated reflectance around 2.1%, which given a normal geothermal gradient is equivalent to a maximum temperature of 205°C for the deepest burial of the formation. There is a dominance of parent polycyclic aromatic hydrocarbons (PAH) over alkylated PAHs, supporting a high thermal maturity. Some samples contain biomarkers suggestive of a marine depositional environment, including the C₃₀ sterane index and the C₃₁/C₃₀ hopane ratio. The Namoi Formation is a prospective shale-gas source, as it has been buried sufficiently to be well within the gas window. Where it is exposed at the surface gas will have been lost, but elsewhere it will be buried beneath other sediments and may still retain gas. Key exploration uncertainties include information on organic richness, lateral variation in thermal maturity, mineralogy, and porosity–permeability relationships.