Whole petroleum system in Jurassic coal measures of Taibei Sag in Tuha Basin,NW China

Based on the latest results of near-source exploration in the Middle and Lower Jurassic of the Tuha Basin,a new understanding of the source rocks,reservoir conditions,and source-reservoir-cap rock combinations of the Jurassic Shuixigou Group in the Taibei Sag is established using the concept of the whole petroleum system,and the coal-measure whole petroleum system is analyzed thoroughly.The results are obtained in three aspects.First,the coal-measure source rocks of the Badaowan Formation and Xishanyao Formation and the argillaceous source rocks of the Sangonghe Formation in the Shuixigou Group exhibit the characteristics of long-term hydrocarbon generation,multiple hydrocarbon generation peaks,and simultaneous oil and gas generation,providing sufficient oil and gas sources for the whole petroleum system in the Jurassic coal-bearing basin.Second,multi-phase shallow braided river delta–shallow lacustrine deposits contribute multiple types of reservoirs,e.g.sandstone,tight sandstone,shale and coal rock,in slope and depression areas,providing effective storage space for the petroleum reservoir formation in coal-measure strata.Third,three phases of hydrocarbon charging and structural evolution,as well as effective configuration of multiple types of reservoirs,result in the sequential accumulation of conventional-unconventional hydrocarbons.From high structural positions to depression,there are conventional structural and structural-lithological reservoirs far from the source,low-saturation structural-lithological reservoirs near the source,and tight sandstone gas,coal rock gas and shale oil accumulations within the source.Typically,the tight sandstone gas and coal rock gas are the key options for further exploration,and the shale oil and gas in the depression area is worth of more attention.The new understanding of the whole petroleum system in the coal measures could further enrich and improve the geological theory of the whole petroleum system,and provide new ideas for the overall exploration of oil and gas resources in the Tuha Basin.

Formation Conditions and Exploration-favoring Areas of Subtle Reservoirs in West Taibei Sag

At the initial stage of subtle reservoir exploration in the shallow to medium formations of the Taibei Sag, Tuha Basin, so far, three kinds of subtle reservoirs (stratigraphic, lithologic and structural-lithologic reservoirs) have been found. Since both the amount and reserve of the discovered subtle reservoirs are small, a great exploration potential remains in the Taibei Sag. The shallow to medium formations in the west of the Taibei Sag were divided into three second-order sequences and ten third-order sequences, of which the rising cyclothems of SQ(J2q) and SQ8 (J2s2) datum level are major exploration targets for the subtle reservoirs (lithologic). The depositional systems of Qiquanhu and Subashi braided river delta were developed there, where the sedimentary sand body is dominated by the regional slopes and slope break belts. There are four main modes the formation of lithologic traps: deltaic front onlap on the slope belt, deltaic front toplap on the slope break belt, lately tilted frontal sand body and sublacustrine fan—slope fan on the slope break belt, of which the first three modes are the major styles of the formation of subtle reservoirs. Major targets for subtle reservoir exploration in the near future include Putaogou Member on the north slope of Huoyanshan, the east slope of Pubei, the nose-like palaeohigh regions of Huobei, Subashi and Lianmuqin, around the Shengbei secondary sag.

Stable carbon and hydrogen isotopic characteristics of natural gas from Taibei sag, Turpan-Hami Basin, NW China

Turpan-Hami Basin is a major petroliferous basin in China. To date the natural gas exploration is concentrated in the Taibei sag. The origin and source of natural gas in the Taibei sag has long been controversial. To further investigate the origin and source of the natural gas in the Taibei sag, combined with previous studies and the local geological backgrounds, this study collected 23 gas samples from the Baka, Qiuling, Shanshan and Wenmi oil fields in the Taibei sag and analyzed the sample composition, stable carbon and hydrogen isotopes of all the gas samples. The results show that, gases from the four oil fields in the Taibei sag are dominated by hydrocarbon gas and belong to wet gas. Methane accounts for 65.84% to 97.94%, the content of heavy hydrocarbon (C2-5) can be up to 34.98%, while the content of nonhydrocarbon (CO2, N2) is trace. The δ13C1 value is –44.9‰ to –40.4‰,δ13C2 is –28.2‰ to –24.9‰,δ13C3 is –27.1‰ to –18.0‰ and δ13C4 is –26.7‰ to –22.1;while the variation of δD1 is not significant from –272‰ to –252‰,δD2 is –236‰ to –200‰ and δD3 is –222‰ to –174‰. Methane and its homologues (C2-5) are characterized by normal stable carbon and hydrogen isotopic distribution pattern, i.e., with the increase of carbon number, methane and its homologues become more and more enriched in 13C or D (δ13C1<δ13C2<δ13C3<δ13C4<δ13C5,δD1<δD2<δD3), which is consistent with the carbon and hydrogen isotopic features of typical thermogenic gas. All these results show that the natural gases in the four oil fields are coal-derived gas with low maturity (Ro averaged at 0.7%), and are sourced from the Middle-Lower Jurassic coal measure. The hydrogen isotopic data of natural gas are affected by both thermal maturity and the water medium of the environment where source rocks are formed. The hydrogen isotopic data indicate that the source rocks are formed in terrestrial limnetic facies with freshwater. Natural gases from Well Ba23 and Well Ke19 experienced biodegradation in the late stage.

First Symposium on Petroleum Across Taiwan Straits Held in Taibei

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Treasures of Taibei Palace Museum

Ilectured at the Taipei Universi-ty of Political Science for three months between May and Aur gust 1994,This gave me a chance to visit the Tibet Buddhist Objects Show put up by the Taiwan Palace Museum,

Geochemical characteristics and possible origin of natural gas in the Taibei Depression,Turpan-Hami Basin,China

292 chemical composition data and 82 isotopic composition data of gas samples collected from the Taibei Depression of the Turpan-Hami Basin, West China, were used in the study of their origin. Non-hydrocarbon gas is poor in most samples whereas abundant nitrogen in some samples is positively correlated with δ13C1. Although methane is the main constituent, higher molecular gaseous hydrocarbons, from ethane to pentane, are detected in most samples, in accordance with the distribution of oil reservoirs. The stable carbon isotope ratios of methane, eth-ane and propane are defined as δ13C1: -45.5‰ to -33.5‰, δ13C2: -30.2‰ to -10.5‰, and δ13C3: 27.6‰ to -11.2‰, respectively. According to the distribution of carbon isotope ratios, 2 families of gas can be grouped, most showing normal distribution of carbon isotopes, and others having obvious heavier carbon isotopes and being of abnormal distribution. Based on the isotopic composition, the disagreement between the relationship of △(δ13C1-δ13C2) and δ13C2 and that of △(δ13C1-δ13C2) and δ13C2, and the calculated Ro, there are oil-associated gas, coal-derived gas and mixture of them. Other samples with obviously heavier isotopic compositions from the Yanmuxi oilfield of the Taibei Depression have been degraded by organisms.

吐哈盆地台北凹陷中侏罗统西山窑组深层煤岩气地质特征与勘探潜力

深层煤岩气是吐哈盆地油气勘探的新领域,但研究程度相对较低。基于煤岩测试与基础资料,系统研究了吐哈盆地台北凹陷中侏罗统西山窑组煤层分布、煤岩煤质、储层物性、宏微观煤岩、煤储层气源及煤岩等温吸附特征,揭示了煤岩储层含气性及其影响因素,提出了深层煤岩气形成富集条件,建立了深层煤岩气富集成藏模式,预测了台北凹陷煤岩气勘探潜力。结果表明:(1)台北凹陷深层侏罗系西山窑组煤层分布广、厚度大,为中低阶、原生结构、割理发育的低灰、低水、富镜质组煤层;(2)煤储层孔渗较高且受埋深影响不明显,煤层段气测异常普遍且储层吸附性能中等—好,具有游离气与吸附气共存、试采快速见气、气组分齐全等特征;(3)台北凹陷煤岩气的油气供给充注,可以形成正向构造带“调整型”和斜坡及洼陷区“自生自储型”两种成藏模式;(4)台北凹陷煤岩气资源丰富,西山窑组主煤层煤岩气资源量近3×10^(12)m^(3)。根据煤岩气资源丰度、煤层厚度、含气量、保存条件等综合评价优选出温吉桑构造带、小草湖南斜坡为深层煤岩气勘探有利目标区。

白先勇《台北人》的“神圣空间”

白先勇《台北人》的表现主题除了以“今昔之比”为主要内容的时间主题外,还有一个更为本质且少有人关注的空间主题,此空间主题可称之为“神圣空间”。在《台北人》中,白先勇通过“时间的空间化”和“空间的时间化”,使空间成为一种具有表现力的积极因素,空间不仅是时间的标识物,而且还是推动时间之流的“框架性的事物综合体”。这导致“今昔之比”的表现内容最后却落实为两个空间的对比,在此基础上,“神圣空间”主题得以凸显和确立。《台北人》叙事中存在着“神圣空间”/“世俗空间”互相比照的空间结构。在此结构中,“神圣空间”是小说人物灵性存在的关键所在,当人物被“贬谪”入“世俗空间”,其灵性以及与灵性相关联的美好品质便趋于消亡。小说人物的塑造就是围绕此“神圣空间”主题而展开。

吐哈盆地台北凹陷侏罗系煤系全油气系统特征

基于吐哈盆地中下侏罗统近源勘探最新成果,以全油气系统理念和思路重新认识台北凹陷侏罗系水西沟群烃源岩、储层条件和生储盖组合,深入解析煤系全油气系统。结果表明:(1)水西沟群八道湾组、西山窑组煤系烃源岩和三工河组泥质烃源岩表现为长时间生烃、具有多个生烃高峰和油气兼生的特点,为侏罗系煤系全油气系统提供充足的油气来源;(2)多期浅水辫状河三角洲—浅湖沉积为斜坡区、洼陷区发育常规砂岩、致密砂岩、煤岩、泥页岩等多类型储层,为油气成藏聚集提供多种储集空间;(3)3期油气充注与构造演化、多类型储层有效配置,形成常规-非常规油气序次成藏聚集的特点,从构造高部位到洼陷区发育远源常规构造油气藏、构造-岩性油气藏,近源低饱和度构造-岩性油气藏和源内致密砂岩气聚集、煤岩储层气、页岩油等类型油气聚集。其中,源内致密砂岩气、煤岩气是当前勘探拓展的重点领域,洼陷区页岩油气值得未来探索研究。煤系全油气系统新认识将进一步丰富完善全油气系统地质理论,为吐哈盆地油气资源的整体勘探部署提供新思路。

吐哈盆地台北凹陷桃东沟群烃源岩风化校正及生排烃潜力

吐哈盆地台北凹陷桃东沟群地层钻井较少,而野外露头往往因风化作用导致地化参数失真。为探明桃东沟群烃源岩受风化影响程度和生排烃潜力,基于岩石热解、总有机碳、镜质体反射率等实验数据,应用风化校正法、生烃潜力法对烃源岩进行了风化校正和生排烃潜力计算。结果表明:风化作用对照壁山、坎尔其和恰勒尔剖面的样品影响较大,对塔尔朗沟剖面样品的影响较小;风化作用对生烃潜量的影响最大,其次是w (氯仿沥青“A”)的影响,对w (TOC)的影响最小;桃东沟群烃源岩有机质类型主要为Ⅲ型和Ⅱ_(2)型,部分为Ⅰ型和Ⅱ1型,有机质丰度较高,为中等—很好烃源岩,Ro为0.53%~1.49%,平均为1.03%,处于成熟阶段;台北凹陷桃东沟群烃源岩在R_(o)为0.62%时达到排烃门限,最大生烃潜力指数为615.88 mg/g,生烃中心位于连木沁次洼北部;桃东沟群烃源岩常规油气地质资源量为2.46×10^(8) t,具有良好的勘探前景。研究成果可为吐哈油田中二叠统桃东沟群油气资源的勘探部署提供理论指导。

吐哈盆地台北凹陷粘土矿物纵向异常演化与成因分析

台北凹陷粘土矿物的成岩演化在纵向上虽然存在伊 /蒙混层中蒙脱石层的基本正常成岩变化规律 ,但是 ,在各成岩阶段其他粘土矿物组分的变化中却出现了多种异常现象 .主要以鄯善构造为例 ,经分析研究后提出了该区粘土矿物在各成岩阶段出现异常变化的多种原因 ,如 :存在原沉积母岩、沉积水介质、煤系地层成岩产生的酸性流体、暗色泥岩热演化生成的有机酸及油层中有机酸等因素的影响 。

吐哈盆地天然气成藏地质条件与富集因素分析

吐哈盆地是我国西北主要的侏罗系含煤盆地,近年来不仅在天然气勘探上迟迟未能取得重大突破,而且发现的天然气田数量及储量规模均远小于油田的数量及储量规模,明显有悖于"含煤盆地贫油富气"的地质规律。为此通过对吐哈盆地天然气成藏地质特征及油气分布规律的解剖分析和探讨,认为煤系源岩成熟度相对较低,天然气转化率较小且明显滞后于液态烃的生成,是造成吐哈盆地"油气共生、油多气少"的主要原因;煤系源岩的热演化程度及油气藏后期的保存条件是盆地大、中型气田形成、富集的关键因素;台北凹陷中部的胜北、丘东和小草湖等地区,煤系源岩发育、热演化程度较高、且后期构造活动相对较弱,应是盆地下一步天然气勘探的最有利地区。

台北凹陷神泉油田断块油气藏特征与控油因素

台北凹陷神泉油田侏罗系油藏储量占全油田的 70 % ,是神泉油田的主力油藏 ,油藏类型为复杂断块油藏。平面上受北东走向断层和东西走向两组断层夹持形成了“墙角式”的 1 6个含油断块 ,各断块之间无统一油水界面 ;纵向上发育 44个油藏 ,单个油藏规模小 ,以低丰度油藏为主。继承性发育的古构造背景控制了油藏的形成与演化 ,正向构造的周全程度影响了油气的富集程度 ,断层封闭的相对性和易变性导致油气分布贫富差异更趋明显、油水关系更加复杂化 ,对这一典型油藏进行分析 ,明确控油因素 ,将有助于进一步明确该区滚动勘探的方向 ,开拓新的找油领域。

吐哈盆地台北凹陷西缘侏罗系层序划分及沉积体系演化

在对吐哈盆地台北凹陷西缘层序地层格架建立的基础上,以区域沉积背景分析为先导,在明确台北凹陷西缘沉积主控因素的前提下,分析准层序组及体系域的叠置样式,划分沉积体系类型,首次在研究区开展了以四级层序为单元的沉积体系展布特征及空间演化分析,为在研究区开展储、盖层评价、生储盖层组合分析、勘探层系优选和各类型油气藏区带评价奠定了基础。

博格达山构造演化对吐哈盆地台北凹陷西缘油气成藏的控制作用

博格达山的构造演化伴随着吐哈盆地成盆、充填的整个过程,盆内构造格局、储层展布、油气运移等与博格达山演化过程密不可分。通过研究台北凹陷西缘发现:燕山期—喜山期博格达山隆升过程直接影响着侏罗系—第三系沉积体系类型及展布特征,进而控制着生、储、盖等成藏要素;中晚燕山期及喜山期隆升形成的逆冲褶皱构造、区域断裂及不整合面控制着圈、运、保等成藏要素,进而控制着北凹陷西缘油气成藏整个过程。中晚燕山期—喜山期六排逆冲褶皱带南、北拓展及各褶皱带间叠合连片为研究区下步有利勘探方向。

台北凹陷温吉桑地区致密砂岩储层特征及其控制因素

通过恒速压汞、CT扫描、X线衍射等实验技术,对台北凹陷温吉桑地区水西沟群致密砂岩储层特征与控制因素进行研究。研究结果表明:研究区砂岩成分、结构成熟度较低,储层致密,储集空间以各类微孔隙和微裂缝为主;微孔隙的形态、分布特征会影响储层喉道半径、孔隙结构,进而影响储层物性,即微孔隙集中连片分布要优于分散孤立分布;沉积于强水动力环境下的粗粒砂岩,有利于原生孔隙的保存和溶蚀孔隙的形成,储层物性好,主要对应于三角洲前缘水下分流河道等沉积微相;在煤系特有的成岩流体环境下,早期快速埋深压实是储层致密化的主要原因,硅质胶结、伊利石胶结、晚期碳酸盐岩胶结等强化储层致密;溶解作用和绿泥石胶结是主要的建设性成岩作用类型;纵向上,浅层(<3.4 km)相对高孔隙度带主要受溶蚀作用影响,深层(>3.8 km)相对高孔隙度带受绿泥石膜影响显著,因此,成岩作用是台北凹陷温吉桑地区致密砂岩储层形成的主控因素。

吐哈盆地鲁克沁稠油藏成藏过程初探与勘探意义

吐哈盆地南部艾丁湖单斜带自１９９３年艾参１井发现三叠系克拉玛依组厚４０ｍ的稠油油砂以来，迄今已发现鲁克沁稠油藏，预计稠油储量规模超过５０×１０６ｔ。该油藏呈底水块状特征，生物降解程度东强西弱、南强北弱、构造高部位强而低部位弱，储集层物性与重质油含油饱和度正相关关系很好，表明原油在进入现今储油层段之前已发生了某种程度的稠变。对成藏过程分析，认为油源主要来自台北凹陷带的二叠系暗色泥岩，运聚成藏主要发生在印支运动末期及燕山运动早期。提出台北凹陷带的二叠系和三叠系勘探目标的选择宜偏北，火焰山断裂构造带下盘构造是勘探前侏罗系有望发现稀油油藏和天然气藏的有利目标。图５参３（王孝陵摘）

吐哈盆地台北凹陷西部侏罗系-古、新近系沉积体系与演化

在建立台北凹陷西部层序地层格架的基础上,通过区域沉积背景分析,明确了台北凹陷西部沉积主控因素,分析了准层序组及体系域的叠置样式,划分了沉积体系类型。首次在研究区开展了以四级层序为单元的沉积体系展布特征及空间演化分析,为储盖层评价、生储盖组合分析、勘探层系优选和各类型油气藏区带评价奠定了基础。

根据遗迹化石确定台北凹陷中侏罗世湖岸带

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