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1.
Well che89, located in the Chepaizi area in the northwest margin of Junggar basin, acquires high production industrial oil flow, which is an important breakthrough in the exploration of the south foreland slope area of Junggar basin. The Chepaizi area is near two hydrocarbon generation depressions of Sikeshu and Shawan, which have sets of hydrocarbon source rock of Carboniferous to Jurassic as well as Upper Tertiary. Geological and geochemical parameters are proper for the accumulation of mixed source crude oil. Carbon isotope, group composition and biomarkers of crude oil in Upper Tertiary of well Che89 show that the features of crude oil in Upper Tertiary Shawan Formation are between that of Permian and Jurassic, some of them are similar to these two, and some are of difference, they should be the mixed source of Permian and Jurassic. Geochemical analysis and geological study show that sand extract of Lower Tertiary Wulunguhe Formation has the same source as the crude oil and sand extract of Upper Tertiary Shawan Formation, but they are not charged in the same period. Oil/gas of Wulunguhe Formation is charged before Upper Tertiary sedimentation, and suffered serious biodegradation and oxidation and rinsing, which provide a proof in another aspect that the crude oil of Upper Tertiary Shawan Formation of well Che89 is not from hydrocarbon source rock of Lower Tertiary.  相似文献   

2.
1 INTRODUCnONThe comPonents of terrigenous sedimenop rocks indicate not only provenance information, but alsotoctOnic evolution of basin. The chdrical composition of the soure rOCks is probaby the major conttDon the chendstry of sedimentny rocks although this can be greaily modified by subsequent Processes(Rollinson l993). Thus, through exndning Petrological and chendcal comPosihons of tenigenoussedlinmp rocks, the comPonentS of the provenance or somee rOCks - which are conunnly a fun…  相似文献   

3.
The Junggar Basin is one of the largest and most petroliferous superimposed petroleum basins in China. The central depression area has become the frontier field for petroleum exploration. The characteristics of potential source rocks and reservoir sandstones, and the pressure regime in the central Junggar Basin were studied. Permian shales are dominated by hydrogen-rich, oil-prone algal organic matter, and Jurassic mudstones are dominated by hydrogen-poor, higher-plant derived organic matter. These source rocks are widespread and have been mature for hydrocarbon generation, suggesting good to excellent exploration potential, both for crude oils and for natural gases. The deeply buried Jurassic sandstones usually have low porosity and permeability. However, sandstones beneath the Jurassic/Cretaceous unconformity display relatively high porosity and permeability, suggesting that meteoric water leaching had improved the quality of the sandstones. Overpressure developed over much of the central Junggar Basin. The overpressured rocks are characterized by slightly increased interval transit time, low sandstone permeability, increased organic matter maturity, and high relative hydrocarbon-gas contents. Mudstones in the overpressured system have quite the same clay mineral compositions as mudstones in the lower part of the normally pressured system. Overpressure generation in the central Junggar Basin is best to be explained as the result of hydrocarbon generation and fluid retention in low-permeability rocks. Petroleum generated from Permian and Jurassic source rocks could migrate laterally through preferential petroleum migration pathways and accumulated in structural traps or lithological traps in the overpressured system, or migrate vertically through faults/hydraulic fractures into the overlying, normally pressured system and accumulate in structural or lithological traps. Therefore, commercial petroleum reservoirs could be potentially found in both the overpressured system, and in the normally pressured system.  相似文献   

4.
Since the discovery of the Tahe oilfield, it has been controversial on whether the main source rock is in the Cambrian or Middle-Upper Ordovician strata. In this paper, it is assumed that the crude oil from the Wells YM 2 and TD 2 was derived from the Middle-Upper Ordovician and Cambrian source rocks, respectively. We analyzed the biomarkers of the crude oil, asphalt-adsorbed hydrocarbon and saturated hydrocarbon in bitumen inclusions from the Lunnan and Hade areas in the North Uplift of the Tarim Basin. Results show that the ratios of tricyclic terpane C21/C23 in the crude oil, asphalt-adsorbed hydrocarbon and saturated hydrocarbon in bitumen inclusions are less than 1.0, indicating that they might be from Upper Ordovician source rocks; the ratios of C28/(C27+C28+C29) steranes in the saturated hydrocarbon from reservoir bitumen and bitumen inclusions are higher than 25, suggesting that they might come from the Cambrian source rocks, however, the ratios of C28/(C27+C28+C29) steranes in oil from the North Uplift are less than 25, suggesting that they might be sourced from the Upper Ordovician source rocks. These findings demonstrate that the sources of crude oil in the Tarim Basin are complicated. The chemical composition and carbon isotopes of Ordovician reservoired oil in the Tarim Basin indicated that the crude oil in the North Uplift (including the Tahe oilfield) and Tazhong Depression was within mixture areas of crude oil from the Wells YM 2 and TD 2 as the end members of the Cambrian and Middle-Upper Ordovician sourced oils, respectively. This observation suggests that the crude oil in the Ordovician strata is a mixture of oils from the Cambrian and Ordovician source rocks, with increasing contribution from the Cambrian source rocks from the southern slope of the North Uplift to northern slope of the Central Uplift of the Tarim Basin. Considering the lithology and sedimentary facies data, the spatial distribution of the Cambrian, Middle-Lower Ordovician and Upper Ordovician source rocks was reconstructed on the basis of seismic reflection characteristics, and high-quality source rocks were revealed to be mainly located in the slope belt of the basin and were longitudinally developed over the maximum flooding surface during the progressive-regressive cycle. Affected by the transformation of the tectonic framework in the basin, the overlays of source rocks in different regions are different and the distribution of oil and gas was determined by the initial basin sedimentary structure and later reformation process. The northern slope of the Central Uplift-Shuntuo-Gucheng areas would be a recent important target for oil and gas exploration, since they have been near the slope area for a long time.  相似文献   

5.
Bitumen from the Nanpanjiang Basin occurs mainly in the Middle Devonian and Upper Permian reef limestone paleo-oil reservoirs and reserves primarily in holes and fractures and secondarily in minor matrix pores and bio-cavities. N2 is the main component of the natural gas and is often associated with pyrobitumen in paleo-oil reservoirs. The present study shows that the bitumen in paleo-oil reservoirs was sourced from the Middle Devonian argillaceous source rock and belongs to pyrobitumen by crude oil cracking under high temperature and pressure. But the natural gas with high content of N2 is neither an oil-cracked gas nor a coal-formed gas generated from the Upper Permian Longtan Formation source rock, instead it is a kerogen-cracked gas generated at the late stage from the Middle Devonian argilla- ceous source rock. The crude oil in paleo-oil reservoirs completely cracked into pyrobitumen and methane gas by the agency of hugely thick Triassic deposits. After that, the abnormal high pressure of methane gas reservoirs was completely destroyed due to the erosion of 2000--4500-m-thick Triassic strata. But the kerogen-cracked gas with normal pressure was preserved under the relatively sealed condition and became the main body of the gas shows.  相似文献   

6.
Lower Cretaceous lacustrine oil shales are widely distributed in southeastern Mongolia. Due to the high organic carbon content of oil shale, many geochemical studies and petroleum exploration have been conducted. Although most of the oil shales are considered to be Early Cretaceous in age, a recent study reveals that some were deposited in the Middle Jurassic. The present study aims at establishing depositional ages and characteristics of the Jurassic and Cretaceous lacustrine deposits in Mongolia. The Lower Cretaceous Shinekhudag Formation is about 250 m thick and composed of alternating beds of shale and dolomite. The Middle Jurassic Eedemt Formation is about 150 m thick and composed of alternating beds of shale, dolomitic marl, and siltstone. The alternations of shale and dolomite in both formations were formed by lake level changes, reflecting precipitation changes. Shales were deposited in the center of a deep lake during highstand, while dolomites were formed by primary precipitation during lowstand. Based on the radiometric age dating, the Shinekhudag Formation was deposited between 123.8 ±2.0 Ma and 118.5 ±0.9 Ma of the early Aptian. The Eedemt Formation was deposited at around 165–158 Ma of Callovian–Oxfordian. The calculated sedimentation rate of the Shinekhudag Formation is between 4.7 ±2.6 cm/ky and 10.0 ±7.6 cm/ky. Shales in the Shinekhudag Formation show micrometer‐scale lamination, consisting of algal organic matter and detrital clay mineral couplets. Given the average thickness of micro‐laminae and calculated sedimentation rate, the micro‐lamination is most likely of varve origin. Both Middle–Upper Jurassic and Lower Cretaceous lacustrine oil shales were deposited in intracontinental basins in the paleo‐Asian continent. Tectonic processes and basin evolution basically controlled the deposition of these oil shales. In addition, enhanced precipitation under humid climate during the early Aptian and the Callovian–Oxfordian was another key factor inducing the widespread oil shale deposition in Mongolia.  相似文献   

7.
The study of Upper Paleozoic and Mesozoic palynomorphs in three boreholes from the Deocha-Pachami area, Birbhum Coalfield, West Bengal, India, has allowed dating of the Talchir, Barakar, Dubrajpur, and Rajmahal formations, and revealed many hiatuses. The lowermost unit, the Talchir Formation, yielded earliest Permian palynomorphs. The Barakar Formation, which includes coal-bearing strata, was previously dated as Early Permian. However, data presented herein indicate an Early Permian to earliest Triassic age for this unit-containing actually the Karharbari, Barakar s.s., Kulti, and Ranigang formations as well as the basal part of the Panchet Formation. The overlying Dubrajpur Formation is Jurassic (Callovian to Tithonian), with an unconformity at its base. The uppermost Dubrajpur Formation is Tithonian-Berriasian. The palynomorphs from the intertrappeans within the Rajmahal Formation suggest an Early Cretaceous age. The revised ages of the Barakar and Dubrajpur formations are of major regional significance. The distribution patterns of spore-pollen may provide a broad spectrum of paleoclimate during Permian, Late Jurassic, and Early Cretaceous times, as there is no record of marine signatures in the study area.  相似文献   

8.
河南省孟州市石庄位于济源盆地东南缘,地层属华北地层区山西分区太行山小区。出露的主要地层有中生界三叠系、新生界第三系、第四系。中生代经历了长期陆相湖盆沉积阶段,岩石中有机物含量高。所以该区中生界地层一直作为煤系地层并进行了煤矿资源的勘查工作。本文通过对中生界上三叠统谭庄组的灰黑色岩系取样分析研究,认为该区上三叠统谭庄组为一套含生油岩地层,是济源盆地东侧生油区。在具备一定的运移、储集及盖层等地质条件下可以形成一定规模的油气资源。为今后在河南西北济源盆地寻找油气资源提供了启示。  相似文献   

9.
羌塘盆地是目前国内石油勘探的热点地区之一,作者综合研究了羌塘盆地的地球物理、石油地质调查资料及INDEPTH-3深部调查结果,得出:1, 盆地内烃源层、储集层、盖层及其组合条件很好, 局部构造发育,有利于形成和保存油气藏,断裂不会成为致命问题,提出了今后工作的主要目的层为上三叠世-中侏罗系组成的中构造层;2,对盆地二级构造作了新的划分,否定羌中隆起,提出盆地表层的主要构造方向为北西-南东向,成“三凹三隆”及“一深凹”的地壳结构特征,其中主沉降带内部及其两侧是最有利的找油气远景地带;3,本区壳幔之间的相互作用较强,盆地北部火山及热活动多,对油气远景评价有较大影响,而盆地南部沉积厚度大,受深层热影响相对较小,是找油气的更有利的地段。4,强调查明深部地层物性、油气赋存状况,烃类物质的来源和上下构造符合情况是当务之急。重点是加强点上的调查和评价研究;5,提出不能轻视伦坡拉陆相第三系盆地找油前景,它可能汇聚有两侧海相地层的油气。  相似文献   

10.
烃源岩热演化是含油气盆地烃源岩评价的基本内容之一,也是油气动态成藏研究的基础.通过系统分析地层沉积样式,结合盆地热史恢复结果,应用Easy%Ro化学动力学模型,模拟了四川盆地86口代表性钻井和200余口人工井点震旦系-下古生界烃源岩热演化史.结果表明,在盆地不同构造单元,下寒武统和下志留统烃源岩热演化特征存在明显差异,并据此建立了四种热演化模式:①加里东期成熟,早晚二叠世期间快速演化定型,以川南地区下寒武统烃源岩为代表;②加里东期未熟,早晚二叠世期间一次快速演化定型,以川西南下寒武统和川南下志留统烃源岩为代表;③加里东期成熟,晚海西-燕山期再次增熟,以川东、川北地区下寒武统烃源岩为代表;④加里东期未熟,晚海西-燕山期持续增熟,以川中地区下寒武统和川东、川北下志留统烃源岩为代表.通过对比研究沉积速率、热流和增温速率之间的耦合关系,剖析了四川盆地震旦系-下古生界烃源岩热演化的控制因素,即川西南和川南局部地区主要受控于早晚二叠世期间峨眉山地幔柱和玄武岩的异常热效应,而盆地其它地区则受沉积地层埋深增热和盆地热流演化的共同作用,其中沉积地层埋深增热对烃源岩增温效应更加显著.  相似文献   

11.

Well Yingnan 2, an important exploratory well in the east of Tarim Basin, yields high commercial oil and gas flow in Jurassic. Natural gas components and carbon isotopic composition indicate that it belongs to sapropel type gas. Because this region presents many suits of hydrocarbon source rocks, there are some controversies that natural gases were generated from kerogen gas or crude oil cracking gas at present. By using the kinetics of hydrocarbon generation and carbon isotope, natural gas of Well Yingnan 2 is composed mainly of crude oil cracking gas, about 72%, it is generated from secondary kerogen gas of Cambrian-Lower Ordovician source rock and crude oil cracking gas of Mid-Upper Ordovician oil reservoir. The main oil and gas filling time is 65 Ma later in the Jurassic gas reservoir of Well Yingnan 2, so the gas reservoir belongs to late accumulation and continuous filling type.

  相似文献   

12.
Zou  Caineng  Yang  Zhi  Sun  Shasha  Zhao  Qun  Bai  Wenhua  Liu  Honglin  Pan  Songqi  Wu  Songtao  Yuan  Yilin 《中国科学:地球科学(英文版)》2020,63(7):934-953
The Sichuan Basin is rich in shale oil and gas resources, with favorable geological conditions that the other shale reservoirs in China cannot match. Thus, the basin is an ideal option for fully "exploring petroleum inside source kitchen" with respect to onshore shale oil and gas in China. This paper analyzes the characteristics of shale oil and gas resources in the United States and China, and points out that maturity plays an important role in controlling shale oil and gas composition. US shale oil and gas exhibit high proportions of light hydrocarbon and wet gas, whereas Chinese marine and transitional shale gas is mainly dry gas and continental shale oil is generally heavy. A comprehensive geological study of shale oil and gas in the Sichuan Basin reveals findings with respect to the following three aspects. First, there are multiple sets of organic-rich shale reservoirs of three types in the basin, such as the Cambrian Qiongzhusi Formation and Ordovician Wufeng Formation-Silurian Longmaxi Formation marine shale, Permian Longtan Formation transitional shale, Triassic Xujiahe Formation lake-swamp shale, and Jurassic lacustrine shale. Marine shale gas enrichment is mainly controlled by four elements: Deep-water shelf facies, moderate thermal evolution, calcium-rich and silicon-rich rock association, and closed roof/floor. Second, the "sweet section" is generally characterized by high total organic carbon, high gas content, large porosity, high brittle minerals content, high formation pressure,and the presence of lamellation/bedding and natural microfractures. Moreover, the "sweet area" is generally characterized by very thick organic-rich shale, moderate thermal evolution, good preservation conditions, and shallow burial depth, which are exemplified by the shale oil and gas in the Wufeng-Longmaxi Formation, Longtan Formation, and Daanzhai Member of the Ziliujing Formation. Third, the marine, transitional, and continental shale oil and gas resources in the Sichuan Basin account for 50%, 25%, and 30% of the respective types of shale oil and gas geological resources in China, with great potential to become the cradle of the shale oil and gas industrial revolution in China. Following the "Conventional Daqing-Oil"(i.e., the Daqing oilfield in the Songliao Basin) and the "Western Daqing-Oil Gas"(i.e., the Changqing oilfield in the Ordos Basin), the Southwest oil and gas field in the Sichuan Basin is expected to be built into a "Sichuan-Chongqing Daqing-Gas" in China.  相似文献   

13.
Synthetical research has been done on the geological thermal history of the Turpan-Hami Basin by using vitrinite reflectance, fluid inclusion geothermometry and fission track. The geotcmperature of the Turpan-Hami Basin has the character that suggests higher temperature in the past, in the east and south of the basin, and in the areas of large-fracture, and lower temperature in the present day and in the west and north of the basin. This feature is controlled by the difference of burial depth of basement and heat flow values, which made Permian source rock mature in the late Triassic and Jurassic source rock mature at the end of Jurassic and the early Tertiary. Project supported by the Chinese Tnrpan-Hami Oil Field cooperation project.  相似文献   

14.
Well Yingnan 2, an important exploratory well in the east of Tarim Basin, yields high commercial oil and gas flow in Jurassic. Natural gas components and carbon isotopic composition indicate that it belongs to sapropel type gas. Because this region presents many suits of hydrocarbon source rocks, there are some controversies that natural gases were generated from kerogen gas or crude oil cracking gas at present. By using the kinetics of hydrocarbon generation and carbon isotope, natural gas of Well Yingnan 2 is composed mainly of crude oil cracking gas, about 72%, it is generated from secondary kerogen gas of Cambrian-Lower Ordovician source rock and crude oil cracking gas of Mid-Upper Ordovician oil reservoir. The main oil and gas filling time is 65 Ma later in the Jurassic gas reservoir of Well Yingnan 2, so the gas reservoir belongs to late accumulation and continuous filling type.  相似文献   

15.
Well Yingnan 2,an important exploratory well in the east of Tarim Basin,yields high commercial oil and gas flow in Jurassic.Natural gas components and carbon isotopic composition indicate that it belongs to sapropel type gas.Because this region presents many suits of hydrocarbon source rocks,there are some controversies that natural gases were generated from kerogen gas or crude oil cracking gas at present.By using the kinetics of hydrocarbon generation and carbon isotope,natural gas of Well Yingnan 2 is composed mainly of crude oil cracking gas,about 72%,it is generated from secondary kerogen gas of Cambrian-Lower Ordovician source rock and crude oil cracking gas of Mid-Upper Ordovician oil reservoir.The main oil and gas filling time is 65 Ma later in the Jurassic gas reservoir of Well Yingnan 2,so the gas reservoir belongs to late accumulation and continuous filling type.  相似文献   

16.
应用含油气盆地热史模拟系统, 对江汉盆地南部的钻井资料进行了模拟计算, 恢复了研究区的热史和埋藏史. 在此基础上, 正演了下志留统烃源岩成熟度的演化史. 研究结果表明,江汉盆地在印支期(240 Ma)以前处于稳定的低热流(50~55 mW/m2)状态, 印支期后热流开始整体升高. 潜北断裂以北地区的热流在中燕山期(155 Ma)达到峰值(~72 mW/m2), 断裂以南的热流在晚燕山期(40 Ma)达到峰值(~76 mW/m2). 晚喜山期后, 整个研究区的热流快速下降, 盆地开始冷却. 早三叠世末, 下志留统烃源岩在枝江、当阳、沔阳凹陷一带率先进入生油门限, 早侏罗世至早白垩世末烃源岩进入快速增熟期, 成熟度具有北高南低的特征. 晚白垩世末, 烃源岩热演化特征表现为东强西弱. 到了新近纪末, 烃源岩热演化终止. 研究区热史恢复和下志留统烃源岩成熟度演化的研究为合理评估烃源岩生烃量、排烃量和油气资源量提供了科学依据.  相似文献   

17.
灵宝盆地位于华北板块南缘与秦岭造山带之间,是豫西北一系列北东-南西向断陷盆地之一.盆地内沉积地层主体为一套厚约2000m陆相碎屑岩夹泥灰岩、薄煤层沉积.本文根据盆地内的恐龙蛋、介形虫、腹足类、哺乳动物化石及少量孢粉等,将地层自下而上划分为下白垩统枣窳组、上白垩统南朝组、古近系古新统-下始新统项城群、中始新统川口组、上始新统庄里坡组及新近系上-中新世(组名暂未定)等6个地层单元.研究表明:下、上白垩统之间及其与项城群之间为不整合或超覆,上中新统与川口组或庄里坡组为不整合接触,整个地层是一套河流相沉积、局部洪泛洼地或小浅湖相沉积.  相似文献   

18.
The Turpan-Harmi (abbreviated to Tuha below) Basin is a typical basin of coal-generated oil accumulation in China. The Middle-Lower Jurassic coal measures are considered the main source beds. Hence, both desmocollinite and suberinite are considered the contributors for coal-generated oil. Principal geochemical features of the crude oil in the Tuha Basin are rich in alkanes (70%—80%), high pristane/phytane ratio (6—8), abundant heavy carbon isotope (δ13C PDB= -26%–-23%) and absolute GP sterane predominance. The hydrocarbon generation process from the coal series is characterized by multistages, early generation and early expulsion.  相似文献   

19.
The stratigraphy and radiolarian age of the Mizuyagadani Formation in the Fukuji area of the Hida‐gaien terrane, central Japan, represent those of Lower Permian clastic‐rock sequences of the Paleozoic non‐accretionary‐wedge terranes of Southwest Japan that formed in island arc–forearc/back‐arc basin settings. The Mizuyagadani Formation consists of calcareous clastic rocks, felsic tuff, tuffaceous sandstone, tuffaceous mudstone, sandstone, mudstone, conglomerate, and lenticular limestone. Two distinctive radiolarian faunas that are newly reported from the Lower Member correspond to the zonal faunas of the Pseudoalbaillella u‐forma morphotype I assemblage zone to the Pseudoalbaillella lomentaria range zone (Asselian to Sakmarian) and the Albaillella sinuata range zone (Kungurian). In spite of a previous interpretation that the Mizuyagadani Formation is of late Middle Permian age, it consists of Asselian to Kungurian tuffaceous clastic strata in its lower part and is conformably overlain by the Middle Permian Sorayama Formation. An inter‐terrane correlation of the Mizuyagadani Formation with Lower Permian tuffaceous clastic strata in the Kurosegawa terrane and the Nagato tectonic zone of Southwest Japan indicates the presence of an extensive Early Permian magmatic arc(s) that involved almost all of the Paleozoic non‐accretionary‐wedge terranes in Japan. These new biostratigraphic data provide the key to understanding the original relationships among highly disrupted Paleozoic terranes in Japan and northeast Asia.  相似文献   

20.
Aromatic hydrocarbons are generally main distillation of crude oil and organic extract of source rocks. Bicyclic and tricyclic aromatic hydrocarbons can be purified by two-step method of chromatography on alumina. Carbon isotopic composition of individual aromatic hydrocarbons is affected not only by thermal maturity, but also by organic matter input, depositional environment, and hydrocarbon generation process based on the GC-IRMS analysis of Upper Ordovician, Lower Ordovician, and Cambrian source rocks in different areas in the Tarim Basin, western China. The subgroups of aromatic hydrocarbons as well as individual aromatic compound, such as 1-MP, 9-MP, and 2,6-DMP from Cambrian-Lower Ordovician section show more depleted 13 C distribution. The 13 C value difference between Cambrian-Lower Ordovician section and Upper Ordovician source rocks is up to 16.1‰ for subgroups and 14‰ for individual compounds. It can provide strong evidence for oil source correlation by combing the 13 C value and biomarker distribution of different oil and source rocks from different strata in the Tarim Basin. Most oils from Tazhong area have geochemical characteristics such as more negative 13C9-MP value, poor gammacerane, and abundant homohopanes, which indicate that Upper Ordovician source rock is the main source rock. In contrast, oils from Tadong area and some oils from Tazhong area have geochemical characteristics such as high 13C9-MP value, abundant gammacerane, and poor homohopanes, which suggest that the major contributor is Cambrian-Lower Ordovician source rock.  相似文献   

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