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1.
Conditions for the Formation of oil and gas pools in Tertiary volcanics in the western part of the Huimin sag, Shandong and then (?)stribution have been studied based on the geological, seismic and well-logging information. In this paper, the types and lithofacies of the volcanic rocks in the western part of the Huimin sag are described; the relationship between rocks and electrical properties, the seismic reflection structures, the development and distribution of the volcanic rocks are expounded; and the fourfold role of the volcanic activities in the formation of the oil and gas pools is also dealt with. It is considered by the authors that the volcanic activities were not destructive to the formation of oil and gas pools but a factor favourable to the accumulation of organic matters and their conversion to hydrocarbon. The volcanic rocks might have served as reservoir rocks and cap rocks, or as a synsedimentary anticline. The prerequisites and important factors for the formation of oil and gas pools and their distribution are pointed out in the paper.  相似文献   

2.
1 Introduction Since the 1990’s of the 20th century, oil & gas geochemists have shifted their research focus on hydrocarbon source rocks in the past to that on reservoir rocks and oil reservoirs at present; their research field has been expanded from oil & gas exploration to the assessment of oil reservoirs and production & management. Therefore, reservoir geochemistry as a branch disciplinary of organic geochemistry is now attracting great concern of many oil & gas explorers and oilfield en…  相似文献   

3.
<正>1 Introduction In early oil and gas exploration in jiyang depression stage,abnormal gas logging and oil and gas shows are frequently seen in the period of the shale.Most wells obtain commercial oil flow,such as Well Luo42,xinyishen9 in zhanhua sag and Well he88 in dongying sag,shows great potential for exploration of fractured shale oil.Once upon a time people in view of the current situation in the research  相似文献   

4.
Based on the analysis of the hydrocarbon geochemical characteristics in the Kuqa petroleum system of the Tarim Basin, this study discusses the causes and controlling factors of the phase diversities and their differences in geochemical features. According to the characteristics and differences in oil and gas phase, the petroleum system can be divided into five categories: oil reservoir, wet gas reservoir, condensate gas-rich reservoir, condensate gas-poor reservoir and dry gas reservoir. The causes for the diversities in oil and gas phases include diversities of the sources of parent material, maturity of natural gas and the process of hydrocarbon accumulation of different hydrocarbon phases. On the whole, the Jurassic and Triassic terrestrial source rocks are the main sources for the hydrocarbon in the Kuqa Depression. The small differences in parent material may cause diversities in oil and gas amount, but the impact is small. The differences in oil and gas phase are mainly affected by maturity and the accumulation process, which closely relates with each other. Oil and gas at different thermal evolution stage can be captured in different accumulation process.  相似文献   

5.
This work discussed the origins, alteration and accumulation processes of the oil and gas in the Kekeya gas condensate field based on molecular compositions, stable carbon isotopes, light hydrocarbons, diamondoid hydrocarbons and biomarker fingerprints. A comparison study is also made between the geochemical characteristics of the Kekeya hydrocarbons and typical marine and terrigenous hydrocarbons of the Tarim Basin. Natural gas from the Kekeya gas condensate field is derived from Middle–Lower Jurassic coal measures while the condensates are derived from Carboniferous–Permian marine source rocks with a higher maturity. In the study area, both natural gas and condensates have experienced severe water washing. A large amount of methane was dissolved into the water, resulting in a decrease in the dryness coefficient. Water washing also makes the carbon isotopic compositions of the natural gas more negative and partially reverse. Considering that the gas maturities are higher than once expected, gas generation intensity in the study area should be much stronger and the gas related to the Jurassic coal measures could promise a greater prospecting potential. As a result of evaporative fractionation, the Kekeya condensates are enriched in saturates and lack aromatics. Evaporative fractionation disguises the original terrigenous characteristics of the light hydrocarbons associated with the natural gas, making it appear marinesourced. Thus, alteration processes should be fully taken into consideration when gas–source correlations are carried out based on light hydrocarbons. With the condensates discovered in the study area all being "migration phase", the pre-salt Cretaceous and Jurassic reservoirs may promise great exploration potential for the "residual phase" hydrocarbons. This research not only is of significance for oil and gas exploration in the southwest Tarim Basin, but also sheds light on the oil/gas-source correlations in general.  相似文献   

6.
Terrigenous clastic reservoir rocks are widespread in China,and nearly all the industrial oil and gas accumulations in eastern China occur in the clastic rocks.The study shows that organic inclusions are mostly distributed in the secondary fissures and pores which were ormed in the process of oil-rock interaction,rather than in the cements or secondary enlargements. The organic inclusions are dominantly organic gas-rich or are composed of pure hydrocarbons.Homogenization temperatures range mainly from 120℃ to 130℃,which shows a relatively high maturity of organic matter.Vertical and horizontal temperature changes provide the grounds for the investigation of basin evolution and thermal fluid-kinetics-model.Fluorescence spectral characteristics o the organic inclusions indicate that oils and gases in the area studied probably have experienced two-stage or two-time migration.Micro-fluorescence rescearch is one of the effective approaches to oil/source correlation and oil migration-stage determination.The abundance and occurrence of organic inclusions is one of the indicators of oil and gas abundance and accumulation in rock layers.With the help of other informatio,organic inclusions can provide the basis for the prospective assessment of oil and gas in clastic reservoir rocks.  相似文献   

7.
The formation conditions and distribution regularities of oil-gas pools in volcanic rocks in western Huimin Depression have been studied in terms of geolgic,sesmic and well logging information,This paper discusses the types and lithofacies,development and distribution of Tertiary volcanic rocks in the area.The results demonstrate that volcanic activity occurred mainly during the period from the Sha-4 stage to the Guantao episode,i.e.,before the oil-generating period(before the end of the Guantao episode and the Minghuazhen episode).The activity did not destroy oil and gas formation and accumulation,but was favourable for the concentration of organic matter and its conversion to hydrocarbons;besides,volcanic rocks can serve as reservoir rocks and cap rocks,playing a role very similar to that of a syndepositional anticline,The volcanic rocks are distributed near the margins of the oil-generating depression;there are many secondary interstices in the rocks,which are connected with each other.These are the leading conditions for the formation of oil-generating period and their self-sealing or good combination with other cap rocks are important factors for forming volcanic rock-hosted oil and gas pools.The oil-gas pools associated with volcanic rocks in western Huimin are mainly distributed around the deep oil-generating depression,in the central up lift or the high structural levels on the margins of the depression.In particular,the sites where several faults cross are usually locatons where hith-yielding oil-gas pools in volcanic rocks are concentrated.  相似文献   

8.
Thickened heavy oils in China are genetically characteristic of continenta .As to their physico-chemical properties,these oils are very high in viscosity and low in sulphur and trace element con-tents.In the group constituents,the concentrations of non-hydrocarbons and asphaltene are very high but those of saturated hydrocarbons and aromatics are very low.The gas chromatograms of alkanes show that these heavy oils have high abundances of iso-alkanes and cyclic hydrocarbons.In all the steroids and terpenoids ,bicyclic sesquiterpenoids,tricyclic diterpenoids,re-arranged steranes and gammacerane are strongly bildegradation-resistent.The formation of heavy oil reservoirs is controlled mainly by late basin ascendance,biodegradation,flushing by meteoric water and oxidation in the oil-bearing formations.Ac-cording to their formation mechanisms,heavy oil reservoirs can be classified as four categories:weathering and denudation,marginal oxidation,secondary migration and thickening of bottom water .Spacially,heavy thick oil reservoirs are distributed regularly:they usually show some paragenetic relationships with normal oil reservoirs.Heavy oil reservoirs often occur in structural highs or in overlying younger strata.Their burial depth is about 200m.Horizontally,most of them are distributed on the margins of basins or depressions.  相似文献   

9.
The Chinese landmass, as a composite region, consists of multiple small continental blocks, such as Sino-Korea, Yangtze, Tarim, etc., and orogenic belts. Because of its distinctive tectonosedimentary evolution, China’s oil/gas-bearing regions differ remarkably from that elsewhere in the world. For instance, in comparison to the Middle East oil/gas-bearing regions which are characterized by Mesozoic-Cenozoic marine oil/gas-bearing beds, early oil and gas discoveries in China are distributed mainly in Mesozoic-Cenozoic continental sedimentary basins. Generation of oil from terrestrial organic matter, or terrestrial oil generation, and the formation of large oil/gas fields in continental sedimentary basins were previously the major characteristics of petroleum geology of China. However, in the past 20 years, a series of major oil and gas discoveries from marine strata have been made. Marine oil/gas fields in China are mainly distributed in the Tarim, Sichuan, and Ordos basins, which are tectonically stable and covered with Mesozoic-Cenozoic deposits. In these basins, hydrocarbon-bearing strata are of old age and the oil/gas fields are commonly deeply-buried. Cumulatively, 995 oil/gas fields have been found so far, making China the fourth largest oil-producing country and the sixth largest gas-producing country in the world. In terms of petroleum and natural gas geology, theories of hydrocarbon generation from continental strata, such as terrestrial oil generation and coal-generated hydrocarbons, etc., have been established. Significant progress has been made in research on the sequence stratigraphy of continental strata, formation mechanisms of ultra-deep clastic reservoirs, and hydrocarbon accumulation in the continental subtle reservoir. Regarding research on the marine petroleum geology of China, with respect to the major characteristics, such as deeply-buried reservoirs, old strata, and multiple phases of transformation, important advances have been made, in areas such as the multiple-elements of hydrocarbon supply, formation of reservoirs jointly controlled by deposition, tectonic activities, and diagenetic fluid-rock reactions, and oil/gas reservoirs formed through superimposed multi-stage hydrocarbon accumulation. As more and more unconventional hydrocarbon resources are discovered, unconventional oil and gas reservoirs are under study by Chinese petroleum geologists, who endeavor to come up with new discoveries on their formation mechanisms.  相似文献   

10.
11.
Complicated oil and gas fields occupy an important position in oil and gas exploration. In this paper, complicated oil and gas fields are grouped into four types: fault-block, lithologic, stratigraphic and fissure types. On the basis of the new theory of petroleum geological exploration in composite oil and gas accumulation areas within continental basins, a new exploration sequence suitable for complicated oil and gas fields has been established, which comprises four stages:(1) initial exploration;(2) preliminary exploration;(3) early step-by-step exploration and development: and(4) late step-by-step exploration and development. The idea of cybernetics has been taken to control various links of a systematic exploration project so as to fully, effectively and comprehensively utilize the new exploration techniques, eventually realizing the optimization of exploration with the aim of raising the efficiency of exploration of complicated oil and gas fields.  相似文献   

12.
The Triassic in the Longmengshan foreland basin is rich in oil and gas resources. Its reservoirs feature low-porosity, low-permeability, small pore throat, high water saturation, and strong heterogeneity. The existence of abnormally high pressure and various reservoir-cap combinations developed at different times provide favorable conditions for trapping oil and gas. Taking the theory of petroleum systems as a guide, and beginning with research on tectonics, sedimentary history, distribution and evolution of source rocks, reservoir evolution, hydraulic force distribution, and hydrocarbon migration, analysis and study of static factors like source rocks, reservoirs and cap rocks, and dynamic factors such as hydrocarbon generation, migration, and accumulation revealed the characteristics of the Upper Triassic petroleum system in western Sichuan province. The deepbasin gas in the central hydrocarbon kitchen of the Upper Triassic, structural-lithological combination traps on the surrounding slopes, and the structural traps of the Indo-Chinese-Yangshan paleohighs, are potential plays. The relatively well- developed fault zones in the southern segment of the Longmengshan foothill belt are favorable Jurassic gas plays. Pengshan-Xinjin, Qiongxi, and Dayi are recent exploration targets for Jurassic oil/gas reservoirs.  相似文献   

13.
<正>Condensates and light oils are generally characterized by high maturity,low concentration of sterane and terpane biomarkers and low content of non-hydrocarbon fraction.As a result,some commonly-used sterane,terpane and carbazole migration parameters in conventional oil reservoirs may have a certain limitation in condensate and light oil reservoirs for their poor signal-noise ratios in the gas chromatography-mass spectrometry(GC-MS).Naphthalene,phenanthrene and their methylated substituents,however,are present in significant concentrations in condensates and light oils.Taking the Fushan depression(in the Beibuwan Basin,Northern South China Sea) as an example, this paper attempts for the first time to use polycyclic aromatic hydrocarbon(PAH)-related parameters to trace migration directions and filling pathways for condensate and light oil reservoirs.The result shows that TMNr(i.e.1,3,7-TMN/(1,3,7-TMN + 1,2,5-TMN),TMN:trimethylnaphthalene)),MPI-1 (i.e.1.5×(2-MP + 3-MP)/(P + 1-MP + 9-MP),P:phenanthrene MP:methylphenanthrene),MN/DMN (Σmethylnaphthalene/Σdimethylnaphthalene,%) and MN/TMN(Σmethylnaphthalene/Σtrimethylnaphthalene, %) can be used to trace the filling pathways of condensate and light oil reservoirs.These parameters,together with geological consideration and other bulk oil properties(e.g.the gas to oil ratio and density),suggest that the condensates and light oils in the Huachang oil and gas field are mainly sourced from the Bailian sag that is located to the northeast of the Huachang uplift in the Fushan depression.  相似文献   

14.
正Objective The Dayangshu Basin located in eastern Inner Mongolia,is one of the key areas for oil and gas exploration in the periphery of Songliao Basin.So far,this basin has been poorly explored,and the basic geological research is still weak,due to the lack of high-quality paleontologic and stratigraphic data.The previous oil and gas investigations were mainly focused on the Early Cretaceous strata.However,the Late Cretaceous Nenjiang Formation in the basin also has hydrocarbon potential according to the latest research.In recent oil and gas geological survey,palynological fossils have been discovered from the Nenjiang Formation in the Dayangshu Basin,providing new evidence for biostratigraphic division and correlation.  相似文献   

15.
This paper,based on the fundamental inorganic chemical and organic geochemical characteristics of oilfield waters from the Turpan Depression,presents the contents of organic matter,the distribution of low-carbon fatty acids and the contents of aromatic hydrocarbons as well as their principal ultraviolet absorption spectral and fluorescence spectral characteristics in oilfield waters from different oil/gas-bearing areas.The oil/gas reservoirs in this depression are classified in terms of their conserving conditions.In additon,the paper also discusses the chemical characteristics of oilfield waters from different types of oil/gas reservoirs with an emphasis on the characteristics of their localization in the γNa/γCa-γN a/γCl correction diagram.On this basis it is attempted to expound the fundamental geochemical characteristics of oilfield waters from the Turpan Depression and their geological significance.  相似文献   

16.
Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule upli  相似文献   

17.
Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule upli  相似文献   

18.
Hydrocarbon Accumulation Conditions of Ordovician Carbonate in Tarim Basin   总被引:5,自引:1,他引:4  
<正>Based on comprehensive analysis of reservoir-forming conditions,the diversity of reservoir and the difference of multistage hydrocarbon charge are the key factors for the carbonate hydrocarbon accumulation of the Ordovician in the Tarim Basin.Undergone four major deposition-tectonic cycles, the Ordovician carbonate formed a stable structural framework with huge uplifts,in which are developed reservoirs of the reef-bank type and unconformity type,and resulted in multistage hydrocarbon charge and accumulation during the Caledonian,Late Hercynian and Late Himalayan. With low matrix porosity and permeability of the Ordovician carbonate,the secondary solution pores and caverns serve as the main reservoir space.The polyphase tectonic movements formed unconformity reservoirs widely distributed around the paleo-uplifts;and the reef-bank reservoir is controlled by two kinds of sedimentary facies belts,namely the steep slope and gentle slope.The unconventional carbonate pool is characterized by extensive distribution,no obvious edge water or bottom water,complicated oil/gas/water relations and severe heterogeneity controlled by reservoirs. The low porosity and low permeability reservoir together with multi-period hydrocarbon accumulation resulted in the difference and complex of the distribution and production of oil/gas/water.The distribution of hydrocarbon is controlled by the temporal-spatial relation between revolution of source rocks and paleo-uplifts.The heterogenetic carbonate reservoir and late-stage gas charge are the main factors making the oil/ gas phase complicated.The slope areas of the paleo-uplifts formed in the Paleozoic are the main carbonate exploration directions based on comprehensive evaluation.The Ordovician of the northern slope of the Tazhong uplift,Lunnan and its periphery areas are practical exploration fields.The Yengimahalla-Hanikatam and Markit slopes are the important replacement targets for carbonate exploration.Gucheng,Tadong,the deep layers of Cambrian dolomite in the Lunnan and Tazhong-Bachu areas are favorable directions for research and risk exploration.  相似文献   

19.
The origin of natural gases in central Tarim Basin is very complicated and there has been no definite conclusion in this aspect. Based on the results of systematic research on their composition and carbon isotopic characteristics, natural gases in central Tarim Basin are composed mainly of hydrocarbon gas, Ordovician natural gas with the characteristics of crude oil-cracking gas, and Carboniferous natural gas not only originating from kerogen cracking, but also from oil cracking. There are significant differences in composition and carbon isotope of natural gases between the eastern and western areas. The causes for the differences in geochemical characteristics of natural gases are presented as follows: different thermal evolution degrees of organic matter. Natural gases in the western region may have generated from the Middle- Upper Ordovician source rocks, and natural gases in the eatern region may be derived from the Cambrian source rocks, which entered into high to over mature stages; the gases migrated from west to east and caused the different compositional and carbon isotopic characteristics of natural gases; difference in the strength of thermal sulfate reduction between the eastern and western parts, with the reduction in the eastern part being stronger than that in the western part.  相似文献   

20.
The new century has witnessed a strategic breakthrough in unconventional oil gas.Hydrocarbon accumulated in micro-/nano-scale pore throat shale systems has become an important domain that could replace current oil gas resources.Unconventional oil gas plays an increasingly important role in our energy demand.Tight gas,CBM,heavy oil and asphaltic sand have served as a key domain of exploration development,with tight oil becoming a 'bright spot' domain and shale gas becoming a 'hotspot' domain.China has made great breakthroughs in unconventional oil gas resources,such as tight gas,shale gas,tight oil and CBM,and great progress in oil shale,gas hydrate,heavy oil and oil sand.China has an estimated(223-263)×10~8t of unconventional oil resources and(890-1260)×l0~(12)m~3 of gas resources.China has made a breakthrough for progress in unconventional oil gas study.New progress achieved in fine-grained sedimentary studies related to continental open lacustrine basin large-scale shallow-water delta sand bodies,lacustrine basin central sandy clastic flow sediments and marine-continental fine-grained sediments provide a theoretical basis for the formation and distribution of basin central reservoir bodies.Great breakthroughs have been made in unconventional reservoir geology in respect of research methodology technology,multi-scale data merging and physical simulation of formation conditions.Overall characterization of unconventional reservoirs via multi-method and multi-scale becomes increasingly popular and facilitates the rapid development of unconventional oil gas geological theory,method and technology.The formation of innovative,continuous hydrocarbon accumulation theory,the establishment of the framework of the unconventional oil gas geological theory system,and the determination of the implications,geological feature,formation mechanism,distribution rule and core technology of unconventional oil gas geological study lays a theoretical foundation for extensive unconventional oil gas exploration and development.Theories and technologies of unconventional oil gas exploration and development developed rapidly,including some key evaluation techniques such as 'sweet spot zone' integrated evaluation and a six-property evaluation technique that uses hydrocarbon source,lithology,physical property,brittleness,hydrocarbon potential and stress anisotropy,and some key development engineering technologies including micro-seismic monitoring,horizontal drilling completion and "factory-like" operation pattern, "man-made reservoir" development,which have facilitated the innovative development of unconventional oil gas.These breakthroughs define a new understanding in four aspects:①theoretical innovation;② key technologies;③ complete market mechanism and national policy support;and ④ well-developed ground infrastructure,which are significant for prolonging the life cycle of petroleum industry,accelerating the upgrade and development of theories and technologies and altering the global traditional energy structure.  相似文献   

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