贵州中南部中三叠世群落古生态研究

文章从群落古生态学的角度,结合岩相学等方面的研究,详细地探讨了贵州中南部中三叠世时的4个生物相、13个群落的特征及其生境,指定了其地理分布范围和生存时限,建立了生物和沉积相模式。认为底栖群落的更替主要由外因——外界环境的变迁引起,而浮游群落的更替则主要由内因——生物自身的进化引起。     

海南岛西北部几处新发现的海滩岩及其意义

在海南岛新发现了三处海滩岩露头。本文从岩石学、沉积学和地球化学等方面探讨了它们的成岩环境,结合~(11)C测年分析,估算出琼西北沿海地区4000多年来的平均构造沉降量大于0.5mm/a。     

Discussion of gas enrichment mechanism and natural gas origin in marine sedimentary basin,China

There are abundant natural gas resources in Chinese marine sedimentary basin. The exploration hot shots of natural gas are the Palaeozoic marine strata here in recent years, and several large scale gas fields have been discovered. Chinese Palaeozoic high-post matured and coal measure hydrocarbon source rocks are mainly prone to gas generation in the present. This research considered that gas source rocks and TSR are the key cause of gas enrichment of marine strata. High-quality argillaceous and coal measure hydrocarbon rocks are distributed widely in the Palaeozoic marine strata, which have been in highly matured phase in the present. The argillaceous source rock generally contains various sulfates that could accelerate crude oil cracking to gas for TSR occurrence, and coal measure source rock mainly generates gas, so Chinese marine basin gives priority to accumulating gas. Marine strata have not founded oil reservoirs in the Sichuan Basin and Ordos Basin, and they consist mainly of dry gas. Marine natural gases are the mixed gases of oil cracking gas and coal-formed gas in a general way, oil cracking gases contain usually some H2S and CO2. Hydrocarbon carbon isotopes are very complicated, and methane and ethane isotopic values bear apparent reversal caused by thermal evolution and mixing among different genetic types of natural gas. Coal-formed gases are the main component of Chinese marine natural gas. The Upper Permian of the Sichuan Basin and the Carboniferous-Permian of the Ordos Basin coal measure hydrocarbon source rock present large hydrocarbon generation potential, which are the prospecting highlight of marine natural gas hereafter. Oil cracking gas exploration will be paid much attention to in the Tarim Basin because of the lack of coal measure hydrocarbon source rock.     

From deep basin gas to diagenetic trap—An example from the Yulin Gas Field in the Ordos Basin

In the updip portion of the Yulin Gas Field in the Ordos Basin, there are no any structural, stratigraphic and sedimentary lithologic seals. Using thin-section petrography, ultraviolet fluorescence microscopy, micro-thermometry and Raman microspectrometry, this paper finds out the diagenetic trap and studies the diagenetic history of this field. It was revealed that three phases of diagenesis and hydrocarbon charging happened in late Triassic, late Jurassic and the end of early Cretaceous respectively. In the first two phases, acid geofluid entered the reservoir and caused dissolution and cementation. Although the porosities had been increased, further compaction accompanying re-subsidence resulted in tight sandstone and conglomerates. Till the end of the early Cretaceous, bulk of gas migrated into the tight reservoir. Cementation, however, kept on in the updip portion of this field due to low gas saturation and formed the diagenetic trap. The mechanism for gas accumulation was changed from deep basin gas to diagenetic trap, which offers a sealing condition that can retain gas for much longer time.     

东濮凹陷濮城地区沙一段盐湖相原油地球化学特征

应用地球化学研究手段，对东濮凹陷濮城地区沙一段盐湖相烃源岩岩样、原油样和油砂样进行了族组分、饱和烃色谱-质谱实验分析。结果表明，濮城地区沙一段原油与含油砂岩抽提物的饱和烃含量在47.39%～65.33%，族组分碳同位素分布在-28.06‰～-26.29‰，芳烃、非烃和沥青质组分之间的同位素分馏效应较小;w（Pr）/w（Ph）小于0.5，具有明显的植烷优势;甾烷w（C2920R）/w（20（R＋S））为0.23～0.27，w（C29ββ）/w（αα＋ββ）为0.19～0.40，甾烷系列中C27含量略占优势，重排甾烷含量极低;γ-蜡烷含量较高，w（γ-蜡烷）/w（C30藿烷）在0.60左右，w（γ-蜡烷）/w（HC3122S）大于2.0，三升藿烷-五升藿烷呈“翘尾”状升序分布，反映了高盐度水体沉积环境下形成的未熟-低熟油特征。油源对比分析认为其烃源灶为沙一段泥岩和部分沙三段泥岩。     

低渗透储层成岩储集相及储集空间演化模式

以砂西油田古近系下干柴沟组下段（E3^1）为例,综合应用取心井的岩石铸体薄片、图像分析、扫描电镜、电子探针能谱、阴极发光、粘土矿物X衍射分析、镜质体反射率等实验测试资料,对E3^1储层的成岩作用、成岩演化序列和成岩阶段划分方法进行了研究,分析了低渗透储层成岩作用对储集物性的影响,详细阐述了低渗透储层中各类成岩储集相的特征及其形成机制,并探讨了其储集空间类型及演化模式。研究结果表明,本区储层砂岩较低渗透率的主要成因是成岩期各种自生矿物的充填和胶结作用。根据成岩作用及其特有的储集空间组合,可将E3^1储层划分为4种成岩储集相类型,即不稳定组分中强溶解次生孔隙成岩储集相（A相）、中等胶结中强压实残余粒间孔成岩储集相（B相）、碳酸盐强胶结成岩储集相（C相）和早期硬石膏强胶结成岩储集相（D相）,其中A类储集相的储集性能最好,D类最差,为差储层或非储层。     

西藏江孜县沙拉岗锑（金）矿区重力流沉积特征

对西藏江孜县沙拉岗锑 (金 )矿区的沉积相进行了划分 ,并重点阐述了颇具特色的各种重力流沉积 (滑动沉积、碎屑流沉积、浊流沉积 ) ,为分析研究锑 (金 )成矿作用提供了丰富的基础资料。     

Fundamental geological elements for the occurrence of Chinese marine oil and gas accumulations

The Paleozoic strata in the Tarim Basin, Sichuan Basin and Ordos Basin are the major targets for marine petroleum exploration, with developed high quality hydrocarbon, mainly argillite. The deep burial of these source rocks suggests that they mainly develop gas instead of oil. But different maturities of organic matter may lead to different hydrocarbon facies. Through thermochemical sulfate reduction （TSR）, the hydrocarbon in the carbonate rocks may undergo a process of pyrolytic cracking and be catalyzed into gases. The marine reservoirs mainly consist of carbonate and clastic rocks, and the former is controlled by sedimentary facies, dolomitization, solution, TSR and cracking. The multiphase tectonic cycling develops multiple source-reservoir-cap combinations and diversified types of traps and reservoirs, featuring multiphase reservoir formation, mainly late-phase formation or consolidation. Palaeo-uplifts play a controlling role in hydrocarbon accumulation. Differences in major source rocks in the three basins lead to different locations of oil-gas accumulation layers, different types and patterns of reservoirs and different features of reservoir formation.     

柴达木盆地北缘第三系沉积体系演化模式

基于柴达木盆地北缘第三系的地质背景和构造演化,结合野外露头、岩心、测井解释和地震相特征,研究了沉积相的纵横分布特征并建立了柴北缘第三系沉积体系演化模式。结果表明:盆地边缘的马北、马西和平台地区一带主要以冲积扇和辫状河沉积为主,靠近湖盆中心的南八仙、冷湖Ⅵ号和Ⅶ号、鄂博梁等地区主要发育辫状河三角洲平原或前缘相带。路乐河组(E1+2)冲积扇较为发育,辫状河相对发育;下干柴沟组(E3)主要发育辫状河和辫状河三角洲沉积,下干柴沟组下段(E13)到下干柴沟组上段(E23)是一个辫状河向辫状河三角洲演化的水进沉积序列;上干柴沟组(N1)和油砂山组(N2)发生进一步湖侵,湖盆扩张,为辫状河三角洲前缘与滨浅湖的交互沉积。在此基础上,建立了柴北缘古近纪—新近纪从物源区向盆地中心发育的冲积扇—辫状河—辫状河三角洲—湖泊沉积体系模式,并探讨了沉积体系演化过程及其油气意义。