Oil-source rock correlation and quantitative assessment of Ordovician mixed oils in the Tazhong Uplift, Tarim Basin

The origin of the marine oils in the Tarim Basin has long been a disputed topic. A total of 58 DST （drill stem test） crude oil and 8 rock samples were investigated using a comprehensive geochemical method to characterize and identify the origin of the Ordovician oils in the Tazhong Uplift, Tarim Basin, northwest China. Detailed oil–oil and oil–source rock correlations show that the majority of the oils have typical biomarker characteristics of the Middle-Upper Ordovician （O2＋3） source rock and the related crude oil. These characteristics include a distinct ＂V-shaped＂ relative abundance of C27, C28 and C29 regular steranes, low abundance of dinosterane, 24-norcholestanes, triaromatic dinosteroids and gammacerane. Only a few oils display typical biomarker characteristics indicating the Cambrian–Lower Ordovician （∈-O1） genetic affinity, such as linear or anti ＂L＂ shape distribution of C27, C28 and C29 regular sterane, with relatively high concentrations of dinosterane, 24-norcholestanes, triaromatic dinosteroids and gammacerane. It appears that most of the Ordovician oils in the Tazhong Uplift were derived from the O2＋3 intervals, as suggested by previous studies. However, the compound specific n-alkane stable carbon isotope data indicate that the Ordovician oils are mixtures from both the ∈-O1 and O2＋3 source rocks rather than from the O2＋3 strata alone. It was calculated that the proportion of the∈-O1 genetic affinity oils mixed is about 10.8%-74.1%, with an increasing trend with increasing burial depth. This new oil-mixing model is critical for understanding hydrocarbon generation and accumulation mechanisms in the region, and may have important implications for further hydrocarbon exploration in the Tarim Basin.

Effective source rock selection and oil–source correlation in the Western Slope of the northern Songliao Basin,China

This study considers the Upper Cretaceous Qingshankou Formation,Yaojia Formation,and the first member of the Nenjiang Formation in the Western Slope of the northern Songliao Basin.Dark mudstone with high abundances of organic matter of Gulong and Qijia sags are considered to be significant source rocks in the study area.To evaluate their development characteristics,differences and effectiveness,geochemical parameters are analyzed.One-dimensional basin modeling and hydrocarbon evolution are also applied to discuss the effectiveness of source rocks.Through the biomarker characteristics,the source–source,oil–oil,and oil–source correlations are assessed and the sources of crude oils in different rock units are determined.Based on the results,Gulong and Qijia source rocks have different organic matter primarily detrived from mixed sources and plankton,respectively.Gulong source rock has higher thermal evolution degree than Qijia source rock.The biomarker parameters of the source rocks are compared with 31 crude oil samples.The studied crude oils can be divided into two groups.The oil–source correlations show that group I oils from Qing II–III,Yao I,and Yao II–III members were probably derived from Gulong source rock and that only group II oils from Nen I member were derived from Qijia source rock.

On the time-varying correlations between oil-,gold-,and stock markets:The heterogeneous roles of policy uncertainty in the US and China

This paper investigates the effects of economic policy uncertainty(EPU)and monetary policy uncertainty(MPU)in the US and China on oil-stock and gold-stock correlations.A quantile regression approach is employed to analyze the heterogeneous impacts under different market correlation regimes.Our findings suggest that the“US impact”prevails across all market correlations in the sample,while“China impact”is found for oil-stock correlations.Furthermore,the impacts of EPU and MPU on correlations of different asset pairs exhibit heterogeneity in direction and in different correlation regimes.EPU and MPU have homogenously negative effects on gold-stock correlations across various correlation regimes.Differently,in terms of oil-stock correlations,they exhibit more significant and stronger positive impacts in the medium and high correlation regime than in the low correlation regime.Gold can provide a better diversification for stock market risks than crude oil during the period of high level of economic uncertainty.

Distribution and isotopic signature of 2-alkyl-1,3,4-trimethylbenzenes in the Lower Paleozoic source rocks and oils of Tarim Basin:Implications for the oil-source correlation

Series of 2-alkyl-1,3,4-trimethylbenzenes(ATMBs)were detected in most of crude oils and source rocks collected from various strata and locations of the Tarim Basin.They appeared to have heavy carbon isotopic signatures(δ13C,up to~-16‰)compared to those hydrocarbons from oxygenic phototrophic organisms,indicating that the unequivocal source of green sulfur bacteria(GSB)and photic zone euxinia(PZE)existed in the original environment.Considering the high paleoproductivity,the PZE may have enhanced the preservation of organic matter,which triggered the formation of extremely organic-rich source rocks with TOC up to 29.8%for the Lower Cambrian Yuertus Formation(€1y).The coexistence of ATMBs and the diagnostic products from secondary alterations(e.g.,abundant 25-norhopanes,thiadiamondoids,and diamondoids)indicated a stronger ability of anti-second-alterations.Combined with the results of quantitatively de-convoluting mixed oil,the oil-source correlation based on ATMBs from a large number of Lower Paleozoic samples of the Tarim Basin suggested that the abundant deep crude oil resources co ntained a dominant contribution(>50%)from the€1y source rocks.Therefore,the ATMBs,as diagnostic biomarkers indicating unequivocal precursors under special habitat conditions,might provide important insights for the exploration of deep Lower Paleozoic crude oils in the Tarim Basin.

Measurement and Correlation of the Solubility of Ligusticum Chuanxiong oil in Supercritical CO_2

有超级批评 CO_2 ( SC-CO_2 )的 Ligusticum Chuanxiong 油的抽取在从 25 MPa 从 55deg 6号元素碳的化学符号 到 70deg 6号元素碳的化学符号和压力到提取的油在抽取的 constanttemperature.The 起始斜率与压力增加了的 Ligusticum Chuanxiong 的 35MPa .The 质量的温度被调查被看作油的溶解度 inSC-CO_2.Chrastil 方程习惯于 Chrastil 方程也是的 Ligusticum Chuanxiong oil.Animproved 的溶解度数据介绍了的相互关联并且被采用相关溶解度 data.Thecorrelation 结果证明偏差是的平均绝对亲戚的价值 5.94 %and3.33%分别地，显示改进版本比那个 ofChrastil 方程有更好的关联精确性。

The Occurrence of Oleananes in the Beibuwan Basin and Its Application to the Study of Maturity and Oil-Source Rock Correlation

The oleanane parameter, i.e., OP （oleananes/（oleananes＋C30hopanes）） in the two sedimentary columns of the Beibuwan Basin, South China Sea, can be used to delimit the top of oil generation window, with Ro （/%） of 0.53 in Well M1 and 0.55 in Wells H1/Hd1/Hd2, respectively. Comparing with vitrinite reflectance （Ro/%）, the OP features a dynamic range and can indicate the oil generation window more precisely. By using OP and other geochemical indices, the oil-source correlation is also conducted. It suggests that the oils in wells M1 and M2 are derived from the source rocks in situ. The mudstone in Huachang uplift is not the main source rocks for oils in this area, The OP is also a useful oil-source correlation parameter in some Tertiary lacustrine basins.

Origin of condensate oil and natural gas in Bozhong 19-6 gas field,Bohai Bay Basin

The discovery of the Bozhong 19-6 gas field has opened a new frontier for deep gas exploration in the Bohai Bay Basin,with a great potential for further gas exploration.However,poor understanding of oil and gas origin has been limiting the exploration progress in this area.To clarify the origin of condensate oil and gas in Bozhong 19-6 gas field,this study adequately utilized the organic geochemical analysis data to investigate the composition and geochemical characteristics of condensate oil and natural gas,and analyzed the relationship between condensate oil and the three sets of source rocks in the nearby subsags.Results show that the lighter components dominate the condensate oil,with a forward type predominance.The parent material of crude oil was primarily deposited in a shallow,clay-rich,low-salinity,weakly reducing aquatic environment.The condensate and natural gas have similar parent source characteristics and maturity,with Ro ranging from 1.4%to 1.6%.Both are products of high maturity stage,indicating that they are hydrocarbon compounds produced by the same group of source rocks in the same stage.Oil-sources correlation shows that condensate oil and gas mainly originate from the source rocks of the third member of Shahejie Formation in the nearby subsags of the Bozhong 19-6 structural belt.

Dibenzofuran Series in Terrestrial Source Rocks and Crude Oils and Applications to Oil-Source Rock Correlations in the Kuche Depression of Tarim Basin, NW China

Ten series of aromatic hydrocarbon compounds (biphenyl, naphthalene, phenanthrene, anthracene, retene, chrysene, benzoanthracene, dibenzofuran, fluorene, dibenzothiophene) isolated from seven Triassic and Jurassic lacustrine mudstone samples and three swamp coal samples, as well as five crude oil samples collected in the Kuche depression of the Tarim Basin, NW China, have been analysed by GC-MS techniques. It is found that the relative abundances of dibenzofuran series are higher in the three swamp coal samples than those in the lacustrine mudstone samples. Based on the similar relative abundances of dibenzofuran series, especially dibenzofuran compound, in the TICs of aromatic hydrocarbons, crude oils from wells SA3 (K), YTK5 (E, K) and QL1 (E) are thought to have been derived predominantly from the coals of the Lower Jurassic Yangxia Formation or Middle Jurassic Kezilenuer Formation, whereas those from wells YM7 (O) and YH1 (E) were derived mainly from Triassic and Jurassic lacustrine mudstones in the Kuche depression. This is the first report about how to distinguish coal-generated oils from lacustrine mudstone-generated oils in the Kuche depression in terms of the dibenzofuran series. The present paper has enlightening and directive significance for further oil-source rock correlations and oil and/or gas exploration in the Kuche depression of the Tarim Basin.

Ruthenium-ion-catalyzed oxidation of asphaltenes and oil-source correlation of heavy oils from the Lunnan and Tahe oilfields in the Tarim Basin, NW China

The identification of marine source rocks in the Tarim Basin is debated vigorously. The intention of this paper is to investigate the asphaltenes in heavy oils from the Lunnan and Tahe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations. The RICO products included n-alkanoic acids, α, ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid , regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bounded on the asphaltenes were of unsusceptibility to biodegradation. The distribution and absolute concentrations of n-alkanoic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields are different from those of Well TD2. The biomarkers bounded on the asphaltenes, especially steranes, have a distribution trend similar to that of the counterparts in saturates. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields, dominated by C-{30} sterane and C-{31} 4-methylsterane carboxylic acids, respectively, are significantly different from those of the heavy oils of Well TD2, whose dominating sterane and 4|methylsterane carboxylic acids are C-{28} sterane and C-{29} 4-methylsterane acids, respectively. The RICO products of the asphaltenes further indicate that the Middle-Upper Ordovician may be the main source rocks for heavy oils from the Lunnan and Tahe oilfields.

The geochemical characteristics and oil-source rock correlation of oilshow from the Majiashan profile, Chaoxian County, South of Anhui Province

In the future time the exploration of marine oil and gas will be one of the significant domains in China. In this paper the biomarker assemblage characteristics of oilshow in the Nanlinghu Formation of the Majiashan pro- file, which is located in Chaoxian County, south of Anhui Province, are described in the light of gas chromatogra- phy/mass spectrometric (GCMS) analysis on the qualitative and quantitative basis. Based on the investigation of the biomarker assemblage characteristics of possible source rocks developed in the area studied, a conclusion is drawn that the oilshow was generated from the Nanlinghu Formation source rocks (abbreviated as T1n), instead of the Qixia Formation source rocks (abbreviated as P1q). It is pointed out that the T1n is of strong potential for future oil explora- tion, and therefore much attention should be paid to it.

Study on oil–source correlation by analyzing organic geochemistry characteristics: a case study of the Upper Triassic Yanchang Formation in the south of Ordos Basin, China

In the south of the Ordos Basin, the oil source of the Upper Triassic Yanchang Formation is confused all the time, which affects further exploration. In this study, oil sources from the oil layers of Ch6, Ch8 and Ch9 are all analyzed and confirmed. Through their carbon isotope value and biomarkers, characteristics of crude oils from the Yanchang Formation are analyzed. Then, the oil–source relation is discussed, with the source rocks' features.Finally, the oil–source relation is calculated through cluster analysis. It is believed that the oils from the Yanchang Formation deposit in a similar redox environment, with weak oxidation–weak reduction, and have all entered maturity stage. Ch9 crude oil is more mature than crude oils from Ch6 and Ch8, and has more advanced plants and fewer algae. Gas chromatography(GC) and gas chromatography–mass spectrometry(GC–MS) analysis show that crude oils from Ch6 and Ch8 may come from Ch7, and Ch9 crude oil may not. Cluster analysis displays that crude oils from Ch6 and Ch8 have closer squared Euclidean distance with Ch7 source rocks than Ch9 crude oil does,indicating crude oils from Ch6 and Ch8 stem from Ch7 source rocks. And Ch9 crude oil has rather close squared Euclidean distance with Ch9 source rocks, illustrating Ch9 crude oil may be from Ch9 source rocks. This research may provide the theoretical basis for the next exploration deploy in the south of Ordos Basin.

Oil-source correlation of the pre-Tertiary in the Huanghua Depression:Insights from stable carbon isotopes and molecular markers

Stable carbon isotopes were used together with molecular markers to constrain genetic relationships between sandstone extracts and potential source rocks in the pre-Tertiary in the Huanghua Depression,North China.Comparison of the extracts from Permo-Carboniferous terrigenous mudstones and Ordovician marine carbonates indicated that their prominent differences are in stable carbon isotopes,molecular markers and thermal maturity.Although the extracts of the Mesozoic and Lower Permian Xiashihezi Formation sandstones have some similar iso-topic characteristics,molecular markers data provide a good correlation between the Upper Jurassic-Lower Cretaceous oils and the Upper Carboniferous Taiyuan Formation mudstones,and between the Lower Permian Xiashihezi Formation oils and the Lower Permian mudstones.The results showed that the Upper Jurassic-Lower Cretaceous sandstone oils were derived chiefly from the Upper Carboniferous Taiyuan Formation terrigenous mudstones and that the Lower Permian Xiashihezi Formation oils were sourced from the Lower Permian Shanxi Formation and Xiashihezi Formation terrigenous mudstones.

An improved correlation to determine minimum miscibility pressure of CO2–oil system

An accurate and reliable estimation of minimum miscibility pressure(MMP) of CO2-oil system is a critical task for the design and implementation of CO2 miscible displacement process.In this study,an improved CO2-oil MMP correlation was developed to predict the MMP values for both pure and impure CO2 injection cases based on ten influential factors,i.e.reservoir temperature(TR),molecular weight of C7+oil components(MWC7+),mole fraction of volatile oil components(xvol),mole fraction of C2-C4 oil components(xC2-C4),mole fraction of C5-C6 oil components(xCs-5-C6),and the gas stream mole fractions of CO2(yCO2),H2S(yH2S),C1(yC1),hydrocarbons(yHC)and N2(yN2).The accuracy of the improved correlation was evaluated against experimental data reported in literature concurrently with those estimated by several renowned correlations.It was found that the improved correlation provided higher prediction accuracy and consistency with literature experimental data than other literature correlations.In addition,the predictive capability of the improved correlation was further validated by predicting an experimentally measured CO2-Oil MMP data,and it showed an accurate result with the absolute deviation of 4.15%.Besides,the differential analysis of the improved correlation was analyzed to estimate the impact of parameters uncertainty in the original MMP data on the calculated results.Also,sensitivity analysis was performed to analyze the influence of each parameter on MMP qualitatively and quantitatively.The results revealed that the increase of xC2-C4,xC5-C6 and yH2 S lead to the decrease of MMP,while the increase of TR,MWC7+,xvol,yCO2,YC1,yHC and yN2 tend to increase the MMP.Overall,the relevance of each parameter with MMP follows the order of TR> xC5-C6> MWC7+> xvol> yH2 S> yHC> yCO2>yC1>yN2>xC2-C4.

Cross-correlation analysis of crude oil and new energy markets: A new perspective based on carbon emission market

Taking the return series of the EU carbon allowance price, WTI crude oil price, the European renewable energy index and Shenzhen carbon emission price, Daqing crude oil price, the China securities new energy index as sample data, the multifractal detrend cross-correlation analysis method(MF-DCCA)is used to research the dynamic cross-correlation relationships among the carbon emission market, crude oil market and the new energy market in Europe and China and the source of the multifractality. The empirical analysis shows that the cross-correlations among the carbon emission market, crude oil market and new energy market in Europe and China have all significant multifractal characteristics. Moreover, the multifractal strength of cross-correlation between the carbon emission market and crude oil market is less than that between the carbon emission market and new energy market in Europe. The Chinese market is the opposite. In addition, the multifractal strength of cross-correlation between the crude oil market and new energy market in Europe is more than that between the crude oil market and new energy market in China. It is also found that the long-range correlation of the sequences themselves and the fat-tailed distribution in fluctuations are the common causes of the multifractality, and the fat-tailed in fluctuations distribution contributes more to the multifractals of the series.

Oil-source correlation of Lower-Triassic oil seepages in Ni＇erguan village, Southern Guizhou Depression, China

There are abundant bitumens and oil seepages stored in vugs in a Lower-Triassic Daye formation(T_1d)marlite in Ni'erguan village in the Southern Guizhou Depression. However, the source of those oil seepages has not been determined to date. Multiple suites of source rocks of different ages exist in the depression. Both the oil seepages and potential source rocks have undergone complicated secondary alterations, which have added to the difficulty of an oil-source correlation. For example, the main source rock, a Lower-Cambrian Niutitang Formation"(∈_1n) mudstone, is over mature, and other potential source rocks, both from the Permian and the Triassic, are still in the oil window. In addition, the T_1d oil seepages underwent a large amount of biodegradation. To minimize the influence of biodegradation and thermal maturation, special methods were employed in this oil-source correlation study. These methods included catalytic hydropyrolysis, to release covalently bound biomarkers from the over mature"kerogen of ∈_1n mudstone, sequential extraction, to obtain chloroform bitumen A and chloroform bitumen C from the T_1d marlite, and anhydrous pyrolysis, to release pyrolysates from the kerogen of T_1d marlite. Using the methods above, the biomarkers and n-alkanes releasedfrom the oil samples and source rocks were analysed by GC–MS and GC-C-IRMS. The oil-source correlation indicated that the T_1d oil seepage primarily originated from"the ∈_1n mudstone and was partially mixed with oil generated from the T_1d marlite. Furthermore, the seepage also demonstrated that the above methods were effective for the complicated oil-source correlation in the Southern Guizhou Depression.

Correlation Dimension in Fault Diagnosis of 600 MW Steam Turbine Generator

GP algorithm of correlation dimension computation is ameliorated which overcomes the shortage of traditional one. Improved process of GP algorithm takes the influence of temporal correlative pairs of points on correlation dimension into account and promotes the computational efficiency prominently. Iterative SVD method is applied to remove the influence of noise on the result of correlation dimension. The faults of steam flow turbulence and oil film disturbance which occur in 600 MW Steam Turbine Generator are analyzed and whose correlation dimensions are computed. More distinct quantitative index than FFT is gained to distinguish two faults and it’s of little importance to apply correlation dimension to study the influence of various factors on steam flow turbulence fault for nonexistence of convergent floor in correlation integral curve, which presents a new way to learn the operational function of large capacity steam turbine generator and carry out comprehensive condition monitoring.

Reclassification and distribution patterns of discovered oils in theDongying Depression, Bohai Bay Basin, China

The Dongying Depression is an important petrolifeous province,with diverse source rocks and complex petroleum distribution patterns.A total of 32 crude oils were analyzed by the gas chromatographyemass spectrometry and isotopic compositions to better understanding the petroleum systems in the study area.Three oil types were classified by hierarchical cluster analyses.Type I and II oils have closely correlation with the discovered source rocks,which have been confirmed to be mainly derived from the lower third and upper forth member of the Eocene Shahejie Formation source rocks(Es3^(L) and Es4^(U)),respectively.Obviously,type III oils contain abundant gammacerane,tricyclic terpanes and C_(29) steranes and have lower values of δ13C than type I and II oils,indicating a completely different source rock and biological origins.Until recently,type III oils fail to match any of the discovered source rock,which contains main contribution of aquatic organism or/and bacteria inputs.In addition,the spacial distribution of these three oil types were discussed.Type I oils mainly distributed in the Es3 and Es4 reservoirs that closed to the generative kitchens.Type II oils occurred in the Es4 reservoirs in the sourthern slope of the depression,which probably caused by lateral migration along the horizontal fractures and sandstone layers within the Es4 interval.Differently,type III oils in the sourthern slope of the depression were mainly discovered in the Eocene Kongdian or Ordocician reservoirs,which suggests great exploration potential of deep underlying strata.

Controlling factors on the charging process of oil and gas in the eastern main sub-sag of the Baiyun Sag,Zhujiang River(Pearl River)Mouth Basin

The eastern main sub-sag(E-MSS)of the Baiyun Sag was the main zone for gas exploration in the deep-water area of the Zhujiang River(Pearl River)Mouth Basin at its early exploration stage,but the main goal of searching gas in this area was broken through by the successful exploration of the W3-2 and H34B volatile oil reservoirs,which provides a new insight for exploration of the Paleogene oil reservoirs in the E-MSS.Nevertheless,it is not clear on the distribution of“gas accumulated in the upper layer,oil accumulated in the lower layer”(Gas_(upper)-Oil_(lower))under the high heat flow,different source-rock beds,multi-stages of oil and gas charge,and multi-fluid phases,and not yet a definite understanding of the genetic relationship and formation mechanism among volatile oil,light oil and condensate gas reservoirs,and the migration and sequential charge model of oil and gas.These puzzles directly lead to the lack of a clear direction for oil exploration and drilling zone in this area.In this work,the PVT fluid phase,the origin of crude oil and condensate,the secondary alteration of oil and gas reservoirs,the evolution sequence of oil and gas formation,the phase state of oil and gas migration,and the configuration of fault activity were analyzed,which established the migration and accumulation model of Gas_(upper)-Oil_(lower)cocontrolled by source and heat,and fractionation controlled by facies in the E-MSS.Meanwhile,the fractionation evolution model among common black reservoirs,volatile reservoirs,condensate reservoirs and gas reservoirs is discussed,which proposed that the distribution pattern of Gas_(upper)-Oil_(lower)in the E-MSS is controlled by the generation attribute of oil and gas from source rocks,the difference of thermal evolution,and the fractionation controlled by phases after mixing the oil and gas.Overall,we suggest that residual oil reservoirs should be found in the lower strata of the discovered gas reservoirs in the oil-source fault and diapir-developed areas,while volatile oil reservoirs should be found in the deeper strata near the sag with no oil-source fault area.

Genesis and distribution of oils in Mahu Sag,Junggar Basin,NW China

Based on the geological and geochemical analysis of potential source rocks in different formations and the classification of crude oil types,combined with the hydrocarbon generation thermal simulation experiments,the source,genesis,and distribution of different types of oils in the Mahu large oil province of the Junggar Basin are investigated.Four sets of potential source rocks are developed in the Mahu Sag.Specifically,the source rocks of the Permian Fengcheng Formation have the highest hydrocarbon generation potential and contain mainly TypesⅡandⅠorganic matters,with a high oil generation capacity.In contrast,the source rocks in other formations exhibit lower hydrocarbon generation potential and contain mainly TypeⅢorganic matter,with dominant gas generation.Oils in the Mahu Sag can be classified as three types:A,B and C,which display ascending,mountainous and descending C_(20)-C_(21)-C_(23)tricyclic terpenes abundance patterns in sequence,and gradually increasing relative content of tricyclic terpenes and sterane isomerization parameters,indicating an increasing oil maturity.Different types of oils are distributed spatially in an obviously orderly manner:Type A oil is close to the edge of the sag,Type C oil is concentrated in the center of the sag,and Type B oil lies in the slope area between Type A and Type C.The results of oil-source correlation and thermal simulation experiments show that the three types of oils come from the source rocks of the Fengcheng Formation at different thermal evolution stages.This new understanding of the differential genesis of oils in the Mahu Sag reasonably explains the source,distribution,and genetic mechanism of the three types of oils.The study results are of important guidance for the comprehensive and three-dimensional oil exploration,the identification of oil distribution in the total petroleum system,and the prediction of favorable exploration areas in the Mahu Sag.

渤海湾盆地南堡凹陷2号构造带油气地球化学特征与来源

渤海湾盆地南堡凹陷2号构造带具有多洼、多层系供烃的特征。为了揭示其复杂的油气来源,开展色谱-质谱等地化测试,分析原油地化特征,将原油分为3类,并确定每类原油的来源。结果表明:(1)Ⅰ类原油主要分布于西构造带沙三段储层中,原油中C27与C29规则甾烷相对含量接近,孕甾烷参数((孕甾烷+升孕甾烷)/规则甾烷)和甾烷异构化参数(C29甾烷20S/(20R+20S)、C29甾烷ββ/(αα+ββ))较高,具有水生生物和高等植物共同输入特征,原油成熟度高,来源于沙三段烃源岩;(2)Ⅱ类原油主要分布于西构造带东二段储层中,原油中C29规则甾烷含量具明显优势,孕甾烷参数和甾烷异构化参数均低,原油母质中高等植物具有明显优势,原油成熟度整体偏低,来源于沙一段—东三段烃源岩;(3)Ⅲ类原油主要分布于东构造带东三段和西构造带东一段和明化镇组储层中,原油中C29规则甾烷具有一定优势,孕甾烷参数较低,甾烷异构化参数较高,以高等植物输入为主,原油成熟度较高,为3套烃源岩的混合来源;(4)原油4-/1-MDBT和Ts/Tm指数具有沿断层向浅部层系减小的趋势,且原油甲基菲换算的镜质体反射率与下覆烃源岩镜质体反射率一致,表明研究区原油具有原地供烃的特点。本研究成果为研究区的浅层精细勘探及深层勘探提供理论指导。