油气、微生物与砂岩型铀矿形成关系研究——以东胜铀矿床和钱家店铀矿床为例

Sandstone-type uranium deposits are frequently found close to oil fields or uraniferous sandstones contain bitumen or petroleum. However, few evidence has been presented to indicate the association of uranium mineralization with petroleum oxidation. Thus, Dongsheng uranium deposit in Ordos Basin and Qianjiadian deposit in Kailu Basin are taken for examples to solve the puzzle. Integration data from sedimentary petrology, mineralogy, race elements geochemistry, isotope geochemistry and organic geochemistry, the uranium and petroleum sources, and diagenetic paragenesis of the host sandstone are analyzed, and then the genetic relationship between microbes, petroleum and uranium deposits are discussed. The observation under microscope shows that the host sandstone samples from Middle Jurassic Zhiluo Formation in the Dongsheng deposit contained different kinds of metamorphic rock fragments, which should have been derived form outcrops north to this basin. The LREE/HREE ratios of gneiss and amphibolite sampled from outcrops were close to the highest and the lowest LREE/HREE ratios of the sandstones with well-compared chondrite-normalized REE patterns, respectively. So these results consistently indicated that parent rocks of sandstones were mainly contributed from these two kinds of metamorphic rocks. There was very high Th/U ratio for granite gneiss, which was a mainly potential U resource. Hydrocarbon inclusions and adsorbed hydrocarbons are observed under fluorescence microscope in the host sandstone of Dongsheng uranium deposit, suggesting that the sandstones may have been utilized as oil migration pathways. Based on biomarker parameters, it is indicated that the inclusion oils and adsorbed hydrocarbons were marginally mature to mature, and were derived from humic-sapropel type organic matter under poor reducing freshwater to semi-saline environment. The features are similar to those of organic matter extracted from Triassic sandstone and source rock, but are different from that of cretaceous sandstone. Thus, it can be concluded that the inclusion oils and adsorbed hydrocarbons were mainly derived from Triassic lacustrine facies source rock. Observation results under Scanning Electron Microscopy and Electron Microprobe with Energy Spectrum Analysis show that, in Dongsheng area, the main uranium ore mineral is coffinite. The coffinite is intimately intergrown or coexists with pyrite and calcite, thus, the solution during mineralization stage is inferred to be alkaline. The alkaline environment is not favored for uranium to be pre-concentrated by absorption, and then be reduced abiogenetically. δ34S of pyrite and δ13C of calcite indicate that pyrite was formed by bacterial sulfate reduction (BSR) and part of the carbon of calcite has been dirived from oxidation of petroleum, respectively. Additionally, petroleum is found biodegraded. All the lines of evidence consistently indicate that petroleum was involved in uranium mineralization. Coffinite with microbe-like structures is found in the high U sandstone samples and is composed of nanoparticles, indicating the coffinite is biogenic. The conclusion are also supportted by laboratory experiment studies, which have shown that SRB are capable of utilizing U(VI) as the preferred electron acceptor for respiration and reduce U(VI) to U(IV) directly, coupled the oxidaton of organic matter and sulfate reduction. Based on the research results mentioned above, in the Dongsheng area, coffinite is likely to have formed by mixing of brine containing petroleum derived from Triassic with uranium-bearing meteoric water from outcrops north to Ordos Basin. SRB utilize hydrocarbon as carbon source, and directly reduce U(VI) resulting in precipitation of coffinite. The product of metabolism, H2S and CO2, was precipitated as pyrite and calcite during mineralization stage. Petroleum in fluid inclusions and adsorbed type in host sandstone from Lower Cretaceous Yaojia Formation in Qianjiadian uranium deposit, Kailu Basin, are derived from Jurassic Jiufotang Formation in this basin and the uranium mineral consists mainly of pitchblende. The δ34S and δ13C values of pyrite and calcite during mineralization stage indicate SRB have likely degraded petroleum, which is similar to that of Dongsheng deposit. The alkaline environment as indicated by the diagenetic mineral assemblage calcite, Fe dolomite, pyrite and pitchblende deposit suggests that U ore in the Qiangjiajiadian has a similar origin, i.e., direct reduction by SRB. However, less part of pitchblende is intergrown with kaolinite, suggesting the solution during mineralization stage is acidic. The environment is favorable for U(VI) to be adsorded on quartz or other mineral, and then reduced by H2S produced by SRB. Thus, it can be concluded that U(VI) reduction with petroleum oxidation by SRB and other microbes is an important ore-forming mechanism in petroleum-related sandstone-type uranium deposits. The finding is significant in that it provides a theoretical basis for exploration of both uranium and petroleumr.

埕北断阶带油气运聚动力学研究

The problem of oil and gas migration and accumulation have been investigated for many years in petroleum geology field. However, it is still the most weak link. It is a challenge task to research the question about the dynamics of hydrocarbon migration and accumulation. The research area of this article,Chengbei step-fault zone is the important exploration area of Dagang oil field.The oil distribution is complicated in this area because of abundant faults and rock-reservoir-cap assemblage.In recent years, oil shows is often discovered, but no large-scale pool is found. The most important problem influencing exolore decision is lake of kowning about accumulation process of oil and resources potential. According to the geology characteristic and exolore difficult, the analysis principles of dynamics is used in this paper. The course from source to reservoir is considered as main research line, and relation of valid source rcok, migration dynamic and heterogeneous distribution of carrier is discussed especially in key time. By use of numerial model the couling of migration and passage is realized and dynamic process of oil migration is analysed quantitatively. On the basis of other research about structure and sendiment, basin model is built and parameters are choiced. The author has reconstructed characteristic and distribution of fluid dynamical in main pool-forming time by numerical model. The systems of oil migration and acuumulaiton are divided according to distribution of fluid potential. Furthermore, the scope of valid sourece rock and scale of discharging hydrocarbon is studied in geology history by the method of producting hydrocarbon poential. In carrier research, it is outstanding to analyse the function that fault controls the oil-gas migration and accumulation. According to the mechanism of fault sealing, the paper author puts forward a new quantitative method evaluating fault opening and sealing properties-fault connective probability by using the oil and gas shows in footwall and hangwall reservoir as the index of identifying fault sealing or non-sealing. In this method, many influencing factors are considered synthetically. Then the faut sealing propery of different position in third deimention of faults controlling hydrocarbon acummulation are quantitative evaluated, and it laies a foundation for building compex carrier systems. Ten models of carrier and dynamical are establishe by analysis of matching relation of all kinds of carriers in main pool-forming period. The forming process and distribution of main pathway has been studied quantitatively by Buoyancy-Percolation mode, which can conbine valid source rock, migration dynamical and carrier. On the basis of oil-gas migration and accumulation model, the author computes the loss of hydrocarbon in secondary migration, ahead of cap formation, and the quantity of valueless accumulation according to the stage of migration and accumulation and the losing mechamism. At the same time, resource potential is evaluated in every migration and accumulation system. It shows that the quanlity of middle systems arrive to 5.67×108t, which has a huge explore potential prospect. Finally, according to the result of quantitve analysis above mentioned, the favorable explore aims are forcasted by the way of overlapping migration pathway and valid trap and considering factors of pool-forming. The drilling of actual wells proved that the study result is credible. It would offer strong support to optimize explore project in Chengbei step-fault zone.

准噶尔盆地滴南凸起中生界层序地层及有利勘探目标优选

Based on the theories of sequence stratigraphy and sedimentology, as well as comprehensive studies of seismic data, drilling data, core interpretation and setting of this area, the thesis presents an analysis for Mesozoic formation in Dinan uplift. By means of recognizing the boundary of the sequence, dividing and correlating the systems tract, Mesozoic of Dinan uplift is divided into ten sequences and twenty-five systems tracts during the establishment of the sequence framework. In the framework, some sequences are featured by mature systems of lowstand, water-transgression and highstand, while some undeveloped systems of lowstand or highstand. The main sedimentary facies in Mesozoic of Dinan uplift are braided river, meandering river, delta and lake. The braided river was divided into sandy river and rudaceous river by the lithology of the river channel and was divided into dry climate and wet climate condition by the color of the flood plain. Additionally, The concept of “wetland” is put forward for the first time and regarded as the consequence of wet climate. The analysis includes the classification of six types of traps: (1) stratigraphic overlap trap, (2) lithologic trap with updip pinchout, (3) stratigraphic unconformity trap, (4) fault-lithology trap, (5) fault trap, (6) anticlinal trap, and combining with the research of the characteristics and distribution rules for the known reservoir, it draws out that “fault control” is the petroleum accumulation pattern in this area, in which fault is the key element of the transporting system. Finally the thesis concludes the distribution characteristics and optimized some targets for the potential exploration zone.

柴达木盆地北缘西段油气运聚动力学研究

Hydrocarbon migration and accumulation are the important process to form reservoirs in sedimentary basins, and their researches are usually very difficult to be done in petroleum geology. In this paper, the west segment of northern margin of the Qaidam Basin was selected as study area. The concept of fault open coefficient, that combines multi-factors dealing with fault sealing, was applied to estimate semi-quantitatively the sealing characteristics of six faults which were considered controlling the hydrocarbon migration and accumulation. The data from boreholes were investigated to appraise the permeable characteristics of lithology combinations upon and beneath the unconformity surface. The result suggests that the basal conglomerates consist frequently the carriers. The data from boreholes and outcrops were collected to describe the sand carrier system. In order to eliminate the influence of inverse activities of the basin that made the formations be very steep, author adopts the phase method to build the basin models: for the steps before Pliocene the recovered true thickness maps were used to build the basin block; for the steps after Pliocene, the structure maps of today were used to build the basin block. During the modeling process, the results were calibrated by various measured data . the modeled results includes the dynamic evolvement course of trap form phase, vitrinite reflectance mature, the source rock expelled hydrocarbon intensity and fluid potential and petroleum plays. Author integrates the source rock expelled hydrocarbon intensity, fluid potential and carrier system and apply the migration technology based on percolation theory to simulate the oil and gas migration and accumulation course in the main accumulation times. The dominant pathways of oil and gas may show clearly the prospect distribution. Based on the hydrocarbon migration characteristics, the main control factors were synthesized, that including the effective source rock distribution, the match relationship of structural trap forming and hydrocarbon expelling from source rocks, the unconformity of Mesozoic and Cenozoic, the structures and the faults movement at Quaternary Finally, the author figures out the prospect plays in the study area.

环渤海花岗岩体地下油库建设的工程地质力学研究

As a kind of strategic resource，petroleum play an very important role in current social stability, economic development and state safety. Since 1993 China has turned from a net oil exporter into a net oil importer, the figure of imported oil increased from then on. In 2004 China's total energy consumption exceeded Japan’s, and ranked in the second place, just inferior to America. Today China is the world’s third-largest importing nation, accounting for 6% of world imports and 8% of world consumption. Comparing with other strategic petroleum reserve schemes, underground oil storage possess many advantages, such as security, economy, less pollution, save land, suited for strategic reserve and so on, so it is the most ideal form for strategic petroleum reserve. In the background of China Strategic Petroleum Reserve Program started just now, this paper choose Circum-Bo sea region as a study area, and do some system study on the underground oil storage caverns constructed in inter-large granite rock masses in Circum-Bo sea region. On the foundation of a great amount of information come from both home and abroad, firstly this paper analysed the principle, economy, cavern shape, profile dimension, and gain some cognizances and logos, as follows: ①Hard rock mass such as granite is the major rock, in which underground oil storage are constructed; ②Unlined underground oil storage caverns had been wide spread used as a sort of oil storage form abroad, there already exist a suit of skilled experience and technologies to prevent oil product from leaking; ③Compared with surface tanks, underground oil storage cavern possess predominance in economy clearly. In general, it will be more economical when the storage capacity exceed 50000m3. The quality of rock mass is the most important factor for underground storage cost, however such as hydrogeology, storage capacity, the number of storage galleries, the length, storage product, mechanical equipments, geographic location also influent the cost. In designed depth of the underground storage, the rock mass of Jinzhou mainly belong to class Ⅱ, but parts with dykes, clayization alteration, and dense joints are Ⅲ, Ⅳ; ④Now, there are few underground oil storages span more than 25m in both abroad and home. The examples of some ancient underground works and modern underground excavation with wide span surely give us many precious elicitations to construct more great unlined storage caverns, when the rock mass quality is good, cavern shape and construction method also are proper, it is quite possible to construct underground oil storage cavern with span more than 30m . The main axis orientation of Jinzhou underground oil storage cavern is NW direction, the cavern's elevation locate between -53msl and -76msl. The storage's total volume is about 3×106m3, composed of 8 parallel galleries with 950m length, the pillars between them are 45m, and every two of galleries form one unit, which can deposit 75×104m3 for each unit. The product will be stored are Saudi light and Saudi medium crude oil, the main cavern's section is 411.5m2, with 23m height and 19m width. According to the principle and technique of engineering geomechanics, this study supply a sort of system scientific thinking and method for sitting location of underground oil storage in granite region: ① On the foundation of the earth crust stability sub-zone appraise of Circum-Bo sea region, farther research concerning granite distribution, genesis, geological period and fault structure are conducted in stable areas, generally, this paper select Liaoxi, east shore of Liaotung peninsula and Jiaotung peninsula as target areas for underground oil storage regions, where Mesozoic granite is magnitude; ②After roundly comparison in facts of geologic structure, engineering geology, hydrogeology, topography, transportation and so on of three granite distributed areas, at last, selecting Jingzhou granite zone in Liaoxi out as an ideal construction area; ③ Detailed investigation is conducted in the southeast of Baimashi in Jingzhou development district, the final field. Ultrasonic Borehole Television, as a major way to collect original information of borehole rock mass were used, which is very effective to appraise the quality of deep rock mass; ④ According to the field data of tectonic stress, rock mass quality, the spatial distribution of fracture water, some optimum designs in cross section, axial direction and cavern span have been designed for the underground oil storage cavern layout in Jinzhou. To understand the characteristics of swelling alteration rock in Jinzhou granite mass, collected abundant swelling alteration rock engineering examples in granite, which study them in detail, concluded the swelling alteration rock distribute nearly everywhere in China, intruded medium-basic dykes alteration, along discontinuities and mineral hydrothermal alteration with genesis of granite are three main forms clayization alteration rock in granite rock mass. In Jinzhou field, from macro to micro studied the swelling rock which induced by mid-basic dyke intrusion, with weak swelling. In conclusion, this paper conclude the distribution rule and features of expansion alteration rock in filed, and advise some technical suggestions for excavation at swelling alteration rock part. The main features of this paper: ①In the process of site selection, investigation and design, a suit of technique and method of engineering geomechanics metasynthesis were formed, which is significative to guide the large scale underground oil storage cavern sitting location, investigation and design in granite rock mass; ②The detailed discussion on the engineering geology problems in granite mass, such as weathering crust, faults, dykes and clayization alteration rock, are useful for other projects in aspects of site selection, engineering geology evaluation and stability estimation; ③The summary and integration of the genesis, type, countermeasure relate to swelling alteration rock, also is likely to be used for other underground oil storage caverns constructed in swelling alteration granite. In conclusion, this study is meaningful for guiding the large scale underground oil storage for site selection, investigation and design in granite rock mass.

均衡重力异常计算与综合解释——以黄海地区为例

Petroleum and Natural Gas is an important strategic resources. The reserves of Petroleum and Natural Gas can’t meet the need of our country, which also blocks the development of economy and threatens the safety of national. Therefore, it makes a great sense to bring “the second round of oil & gas exploration” into effect and study the exploration of oil and gas of Pre-Cenozoic residual basins in China. The integrated geophysical exploration is the main way to research the Pre-Cenozoic residual basins. Gravity exploration is one of the most important exploration methods, which has played an important role in oil and gas prospecting, such as compartmentalizing geotectonic elements, delineating the distribution range of sedimentary basins, searching oil and gas structure, abstracting oil and gas information, and so on, from its naissance. The isostatic gravity anomalies is significant for exploration, which can help us research deep crustal structure, the equilibrium state of earth, the geologic structure of shallow crust, the basement shape of sedimentary basins and the genetic evolution of sedimentary basins. In the paper, we stress the implication and physical meanings systemically, and discuss the calculation theory. On the basis of previous work, we test different isostatic compensation models and parameters to find out their influences to the result of isostatic gravity anomalies. In addition, we improve the method of isostatic gravity anomalies calculation and give a system of isostatic gravity anomalies calculation which is proved has satisfying effect. From the research above, we find that the results of Platt model and Airy model are consistent, which have similar form and almost the same value. However, by contrast, the Airy model is proved has better adaptability than Platt model. The two main parameters——crust thickness and density difference of crust and mantle, both have influence to the isostatic gravity anomalies, but the latter have more. Finally, we adopt the regional field extending edge method to make the result more of actual geologic condition. On the methods above, we calculate the isostatic gravity anomalies field in Yellow Sea area from the Bouguer gravity anomalies and the water depth and altitude data. And then the isostatic gravity anomalies character is analyzed and the integrated geological-geophysical interpretation is made on the basis of summarizing the previous research result systemically and analyzing other geophysical data and geological information. From the research, we find that the Yellow Sea area belongs to continental type crust equilibrium regions, where the isostatic gravity anomalies field is placid and has less fluctuation values, which implies that the area is in equilibrium state to different extends.

砂泥岩薄互层储层预测方法与应用研究

With the deeply development of exploration and development in petroleum in China, new increasing reserves are found in old oil fields and the verge of the old ones through re-study of geological property. It is more and more important to discovery and develop thin layer or thin inter-bedded layers reservoirs. All of the targets are thin sand-shale inter-bedded reservoirs and the core technology is reservoir predictions between wells in thin sand-shale inter-bedded layers. The continuity of the thin sand-shale inter-bedded layers in space or separating and heterogeneity is the key of reservoir geology research. The seismic reflection, high resolution analysis method and inversion method to thin sand-shale inter-bedded layers are thorough discussed and deeply studied in this paper to try to find the methods and resolutions of reservoir geology research. The below is followed. 1. Based on the pre-research of other people, five models are created: the sand sphenoid body, interlay sandstone and interlay shale of the equal thickness, interlay sandstone of the equal thickness and interlay shale of the unequal thickness, interlay sandstone of the unequal thickness and interlay shale of the unequal thickness, interlay sandstone of the changing thickness in sequence and interlay shale of the changing thickness in sequence. Then the study of the forward modeling are conducted on the thin layer and thin inter-bedded layers geological characters and seismic reflections including amplitude, frequency, phase, wave shape and time-frequency responding in the domains of time and frequency. The affect of petro-physics difference of layers, single thin layer thickness, thickness of inter-bedded, layer number of inter-bedded, incident wavelet domain frequency and types, sample interval to seismic reflection characters, frequency spectrum and time-frequency respond of reflectivity is theoretically discussed. 2. Qualitatively analyzing the sedimentary rhythm of the thin inter-bedded layers in vertical orientation and computing the single layer thickness or the average thickness with the method of generalized S transform. Identifying the reflecting interface or lithology interface using the amplitude value of amplitude spectrum domain frequency. 3. Based on the seismic respond of thin sand-shale inter-bedded layers, bring out the high resolution analysis method of seismic data in thin sand-shale inter-bedded layers using wavelet analysis and the idea of affecting low and high frequency with middle frequency. Then analyzing the effect to the method and testing some wavelets in the method. This method is applied to the theoretical models and the field data. 4. Bring forward one improved very fast simulated annealing method (IVFSA) to resolve the problem nonlinearity and multi-parameters of the inversion in thin inter-bedded layers. And IVFSA is more productive and higher precision than general ways. 5. New target constrained function is used in the inversion based on the property of the inversion in thin inter-bedded layers. 6. Making the full use of geological and logging information, IVFSA and the new function are applied in the non-linear inversion to improve reservoir prediction and evaluation in thin inter-bedded formations combined with the idea of logging and seismic inversion. This method was applied to the field data and got good results.

奇异性分析方法及其在储层预测中的应用研究

In research field of oil geophysical prospecting, reservoir prediction is refers to forecasting physical properties of petroleum reservoir by using data of seismic and well logging, it is a research which can guide oil field development. Singularities of seismic and logging data are caused by the heterogeneity of reservoir physical property. It's one of important methods that using singularity characteristics of seismic and logging data to study the reservoir physical property in recently. Among them, realization of reservoir quantitative prediction by analyzing singularity of the data and enhancing transition description of data is difficulty in method research. Based on wavelet transform and the fractal theory, the paper studied the singularity judgment criterion for seismic and logging data, not only analyzed quantitative relation between singularity data and reservoir physical property, but also applied it in practical reservoir prediction. The main achievements are: 1. A new method which provides singular points and their strength information estimation at only one single scale is proposed by Herrmann (1999). Based on that, the dissertation proposed modified algorithm which realized singularity polarity detection. 2. The dissertation introduced onset function to generalize the traditional geologic boundaries variations model which used singularity characteristics to represent the abruptness of the lithologic velocity transition. We show that singularity analysis reveals generic singularity information conducted from velocity or acoustic impedance to seismogram based on the convolution seismic-model theory. Theory and applications indicated that singularity information calculated from seismic data was a natural attribute for delineating stratigraphy boundaries due to its excellent ability in detecting detailed geologic features. We demonstrated that singularity analysis was a powerful tool to delineate stratigraphy boundaries and inverse acoustic impedance and velocity. 3. The geologic significances of logging data singularity information were also presented. According to our analysis, the positions of singularities indicate the sequence stratigraphic boundary, and there is subtle relationship between the singularity strength and sedimentary environment, meanwhile the singularity polarity used to recognize stratigraphic base-level cycle. Based on all those above, a new method which provided sedimentary cycle analysis based on the singularity information of logging data in multiple scales was proposed in this dissertation. This method provided a quantitative tool for judging interface of stratum sequence and achieved good results in the actual application.

南襄盆地泌阳凹陷断裂斜坡带构造特征与油气成藏

The faulted slope zone of Biyang depression, a multiple hydrocarbon accumulation zone lying in a rich oil depression of Nanxiang basin, is a structural-sedimentary compounded slope, which is developed in Yanshanian period and has an area of 500 km2. From the ‘bottom up’, the developed strata may be divided into Yuhuangding formation in Neogene, Dacang Fang, Hetao-yuan plus Liaozhuang formations and Fenghuangzheng plus Pingyuan formation in Neogene, while Hetao-yuan formation is the main hydrocarbon-bearing target. Because of transtensional stress fields formed by persistent action of large-scale faulting in the south of the depression, sedimentary differential compaction in different stages, and tectonic inversion in later developing stage of the depression, a series of nose structure zones cut by different strike faults are developed. Therefore, the reservoir migration and accumulation are controlled by the complex faulted-nose structural zone, reservoir types are dominated by faulted-noses, faulted-blocks and fault-lithology, while lithology and stratigraphic unconformable reservoirs are locally developed. In combination with demands of practical production, applying with a new research approach of systematology and a combination with dynamic and static modes, guided by modern petroleum geologic theory, and based on previous data and studies, new techniques, methods of geophysical exploration, various computer simulation and forecasting techniques are applied in the new research of this paper. Starting from the structural features and formation mechanism, the forming mechanism of faulted structure, conditions and controlling factors of hydrocarbon accumulation, as well as various space-time allocation relationships in the process of accumulation are analyzed in the research. Besides that, the hydrocarbon migration, accumulation mechanism and dynamic evolution process are also discussed in the paper. Through the research, the accumulation rule of the faulted slope zone in faulted lake basin, the distribution and enrichment regularity of different reservoir controlling factors are systematically summarized. The summarizations indicate that the faulted slope is a favorable orientational zone, hydrocarbon is accumulated in nose structures and enriched in the main body of nose structures, faulted transformation zone and the ascent direction of laddering faulted blocks, the faults are the controlling factors, hydrocarbon accumulation zones controlled by fault-lithology are distributed along the faulting direcion. In the end, hydrocarbon migration and accumulation models of complex faulted-nose blocks are established. 1) Down cut model—‘flank-sheet’: the hydrocarbon is migrated like ‘sheet’ along a series of faults with parallel distribution and accumulated in the flank of nose structures; 2）Cross cut --‘axis-string’ model: the hydrocarbon cutting across the faults is migrated like ‘string’ and accumulated in the axis of nose structures. In view of different distribution models, reservoir forming combination patterns are divided and hydrocarbon reservoir evaluation exploration is carried out, which achieves good results in application. Key words: faulted slope zone; migration and accumulation model; reservoir controlling mechanism; reservoir-forming combination

陕北何家集区延长组长4＋5－长6储层特征研究

Abstract： Hejiaji area lies on eastern part of Shanbei Slope in Ordos Basin and the primary oil-bearing bed is Chang 4＋5 and Chang 6 of Yanchang Formation. It is indicated that the sedimentary facies and reservoir characteristics restricted the hydrocarbon accumulation regularity by the geological information. Therefore, Applied with outcrop observation，core description, geophysical logging interpretation, thin section determination, Scanning Electron Microscope, reservoir lithology and physical property analysis and other analytic machinery, the sedimentary facies ,micro-characteristic and master control factors on hydrocarbon reservoir of Yanchang Formation in Hejiaji area are studied deeply by means of sedimentology，reservoir geology and petroleum geology and provide a reliably reference for later prospect . Delta facies are identified in Hejiaji area and of which distributary channels in delta plain microfacies controlled the distribution of sand bodies and accumulation of oil and gas.The distribution of sand bodies distributed from northeast to southwest are dominated by sedimentary facies . It was shown that the sandstones are medium to granule arkose，which the mud matrix is r and including，calcite，the content of matrix is lower and that mostly are cements which are mainly quartz and feldspar overgrowths and chlorite films, in the second place are hydromica and ferrocalcite. All the sandstones have entered a period of late diagenetic stage in which the dominant diagenesis types in the area are compaction, cementation and dissolution. Remnant intergranular porosity and feldspar dissolved pore are main pore types which are megalospore and medium pore. Medium-fine throat, fine throat and micro-fine throat are the mainly throat type. Pore texture can be classified as megalospore and fine throat type, medium-pore and micro-fine throat type mainly, and they are main accumulate interspace in research region. The reservoir of Yanchang Formation in Hejiaji area is low- pore and low- permeability in the mass which have strong heterogeneity in bed, interbedded and plane. Studying the parameter of pore and permeability comprehensively and consulting prevenient study results of evaluation of reservoir, the reservoir is classifiedⅡ，Ⅲ and Ⅳ three types in which the Ⅱand Ⅲ can be divided into Ⅱa and Ⅱb, Ⅲa and Ⅲb respectively. Ⅱb and Ⅲa are the main reservoir type in Hejiaji area which are about 72.73％and 80％percent of whole reservoir and effective reservoir respectively.

陕北地区石家湾-李家岔探区三叠系延长组石油成藏条件分析

Shijiawan –Lijiacha area, lying on the northeastern part of the Shanbei Slope of Ordos Basin, was selected as studying area. The previous explorations proved that the 2nd segment and 6th segment of the Yanchang Formation are the most important oil-bearing formations. It is indicated that the sedimentary facies and reservoir characteristics restricted the hydrocarbon accumulation regularity. Therefore, with petrology methodologies, such as outcrop observation, core description, geophysical logging interpretation, thin section determination, scanning electron microscope, as well as rock property analysis, the reservoirs was were systematically studied and characterized. The sedimentary micro-facies, seals, reservoir-seal combines, migration pathways and entrapping modes were taken into account. The author tempted to establish a base for further studies on reservoirs and on petroleum geology, and to provide some reliably geological evidences for later prospect activities. It was found that the sediments in the 2nd and 3rd segments of the Yanchang Formation in Shijiawan –Lijiacha area were deposited in braided rivers, and most sandy-bodies were identified as channel sandbars. The 4+5th and 6th segments were principally deposited in deltaic-plain environment, consisting of corresponding sub-facies such as distributary channels, natural levee, crevasse-splay and marsh. The skeleton sandy-bodies were identified as sandy sediments of distributary channels. The sand grains in reservoir in studied area possess generally low mineralogical maturity and moderate structural maturity, and the form of pores may be classified into intergranular types and dissolved types. Most reservoirs of Yanchang Formation in Shijiawan –Lijiacha area belong to extreme low-porosity low-permeability ones (type III), and the 2nd sediments belongs to low permeability one (type II) and the 6th segment belong to super low-permeability one(type Ⅳ). The reservoirs in the 2nd segment behave more heterogeneous than those in the 6th segment. The statistic analysis results show that, for 6th and 4+5th segments, the high quality reservoir-seal combines may be found everywhere in the studied area except in the northwest and the southwest parts; and for 1st and 2nd segments, in the northeast, central and southwest parts Petroleum migration happened in the duration of the Early Cretaceous period in both lateral and vertical directions. The migration paths were mainly constructed by permeable sandy-bodies. The superimposed channel sandy-bodies consist of the principal part of the system of carriers. the vertical fractures, that may travel through the seals between reservoirs, offered the vertical paths for migrating oil. It may be synthesized that oil coming from south kitchens migrated first laterally in carriers in the 6th segment. When arrived at the studied area, oil will migration laterally or/and vertical within both the sandy-bodies and fractures, in a climbing-stair way. The results demonstrate that the oil was entrapped in traps structure-lithology and/or lithology traps. In some cases, the hydrodynamic force may help to trap oil. Accumulation of oil in the area was mainly controlled by sedimentary facies, seals, structure, and heterogeneity of reservoir in the 2nd, 4+5th and 6th segments. Especially, the oil distributions in both the 2nd and 6th segments were obviously influenced by seals in the 4+5th segment. The existence of seals in 1st segment seems important for accumulation in the 2nd segment.

陕北桥镇油田延长组长2、长1油层组沉积相及储层研究

The Ordos Basin is a large-scale craton superimposed basin locating on the west of the North China platform, which was the hotspot of interior basin exploration and development. Qiaozhen oil field located in the Ganquan region of south-central of Ordos Basin. The paper is based on the existing research data, combined with the new theory and progress of the sedimentology, sequence stratigraphy, reservoir sedimentology, petroleum geology, etc, and analyzes systematically the sedimentary and reservoir characteristics in the chang2 and chang1 oil-bearing strata group of Yanchang formation On the basis of stratigraphic classification and comparison study, the strata chang2 and chang1 were divided into five intervals. Appling the method of cartography with single factor and dominance aspect, we have drawn contour line map of sand thickness, contour line map of ratio between sand thickness and stratum thickness. We discussed distribution characteristics of reservoir sand body and evolution of sedimentary facies and microfacies. And combining the field type section , lithologic characteristics, sedimentary structures, the sedimentary facies of single oil well and particle size analysis and according to the features of different sequence, the study area was divided into one sedimentary facies、three parfacies and ten microfacies. The author chew over the characteristics of every facies, parfacies and microfacies and spatial and temporal distribution. Comprehensive research on petrologic characteristics of reservoir , diagenesis types, pore types, distribution of sand bodies, physical properties, oiliness, reservoir heterogeneities, characteristics of interlayer, eventually research on synthetic classifying evaluation of reservoir.The reservoir is classified four types: Ⅰ、Ⅱ、Ⅲ、Ⅳ and pore type, fracture-porosity type. Take reservoir's average thickness, porosity, permeability, oil saturation and shale content as parameters, by using clustering analysis and discriminant analysis, the reservoir is classified three groups. Based on the evaluation, synthetizing the reservoir quality, the sealing ability of cap rock, trap types, reservoir-forming model ,in order to analyze the disciplinarian of accumulation oil&gas. Ultimately, many favorable zones were examined for chang23，chang223，chang222，chang221，chang212，chang12，chang11 intervals. There are twenty two favorable zones in the research area. Meanwhile deploy the next disposition scheme.

油气勘探风险评价与决策技术研究

PetroChina and other national petroleum incorporations need rigorous procedures and practical methods in risk evaluation and exploration decision at home and abroad to safeguard their international exploration practice in exploration licence bidding, finding appropriate ratio of risk sharing with partners, as well as avoiding high risk projects and other key exploration activities. However, due to historical reasons, we are only at the beginning of a full study and methodology development in exploration risk evaluation and decision. No rigorous procedure and practical methods are available in our exercises of international exploration. Completely adopting foreign procedure, methods and tools by our national incorporations are not practical because of the differences of the current economic and management systems in China. The objective of this study is to establish a risk evaluation and decision system with independent intellectual property right in oil and gas exploration so that a smooth transition from our current practice into international norm can take place. The system developed in this dissertation includes the following four components: 1. A set of quantitative criteria for risk evaluation is derived on the basis of an anatomy of the parameters from thirty calibration regions national wide as well as the characteristics and the geological factors controlling oil and gas occurrence in the major petroleum-bearing basins in China, which provides the technical support for the risk quantification in oil and gas exploration. 2. Through analysis of existing methodology, procedure and methods of exploration risk evaluation considering spatial information are proposed. The method, utilizing Mahalanobis Distance (MD) and fuzzy logic for data and information integration, provides probabilistic models on the basis of MD and fuzzy logic classification criteria, thus quantifying the exploration risk using Bayesian theory. A projection of the geological risk into spatial domain provides a probability map of oil and gas occurrence in the area under study. The application of this method to the Nanpu Sag shows that this method not only correctly predicted the oil and gas occurrence in the areas where Beibu and Laoyemiao oil fields are found in the northwest of the onshore area, but also predicted Laopu south, Nanpu south and Hatuo potential areas in the offshore part where exploration maturity was very low. The prediction of the potential areas are subsequently confirmed by 17 exploration wells in the offshore area with 81% success, indicating this method is very effective for exploration risk visualization and reduction. 3. On the basis of “Methods and parameters of economic evaluation for petroleum exploration and development projects in China”, a ”pyramid” method for sensitivity analysis was developed, which meets not only the need for exploration target evaluation and exploration decision at home, but also allows a transition from our current practice to international norm in exploration decision. This provides the foundation for the development of a software product “Exploration economic evaluation and decision system of PetroChina” (EDSys). 4. To solve problem in methodology of exploration decision, effort was made on the method of project portfolio management. A drilling decision method was developed employing the concept of geologically risked net present value. This method overcame the dilemma of handling simultaneously both geological risk and portfolio uncertainty, thus casting light into the application of modern portfolio theory to the evaluation of high risk petroleum exploration projects.

南海北部陆缘深水区构造－热演化与烃源岩成熟度史研究

Abstract In order to provide basic data for evaluation of the petroleum potential in the deep water area of the northern margin of the South China Sea (SCS), present-day thermal regime and basin tectonothermal evolution are reconstructed and the maturation history of the Cenozoic major source rocks in the study area is derived. The present-day geothermal regime in the deep water area of the northern margin of SCS is defined according to the geothermal gradient, thermal properties and heat flow data. Tectonic subsidence history is reconstructed based on borehole and seismic data, and accordingly the stretching episodes are determined from the subsidence pattern. Heat flow history in the deep water area of the northern margin of SCS is estimated on a finite time, laterally non-uniform and multi-episode stretching model. Maturation history of the main source rocks in the study area is estimated through EASYRo% kinetic model and thermal history, and the potential of petroleum in the deep water area of the northern margin of SCS is evaluated based on the data above. The results show that the present-day geothermal regime in the deep water area of the northern margin of SCS is characterized by “hot basin” with high geothermal gradient (39.1±7.4℃/km) and high heat flow (77.5±14.8 mW/m2), and that the Qiongdongnan Basin (QDNB) underwent three stretching episodes and consequently suffered three heating episodes (Eocene, Oligocene and Pliocene time) with highest paleo-heat flow of 65～90 mW/m2 at the end of the Pliocene, that the Pearl River Mouth Basin (PRMB) two stretching and two heating episodes (Eocene, Oligocene time) with highest paleo-heat flow of 60～70 mW/m2 at the end of the Oligocene, and that the source rocks matured drastically responding to the heating episodes. There are four hydrocarbon generation kitchens in the deep water area of the northern margin of SCS which are favor of its bright petroleum perspective. Tectonothermal analysis indicates that the present-day geothermal regime which is characterized with “hot basin” in the deep water area of the PRMB resulted mainly from the Cenozoic stretching as well as faulting and magmatic activities during the Neotectonic period, and that the Pliocene heating episode of the QDNB is coupled with the transition from sinistral to dextral gliding of the Red Rive fault, and that the deep water basins in the northern margin of SCS are typical of multiple rifting which caused multi-episode heating process.

鄂尔多斯盆地陇东地区长8段砂岩输导体定量表征研究

Migration carriers act as the “Bridges” connecting source rock and traps and play important roles in petroleum migration and accumulation system. Among various types of carriers, sandstone carrier constitutes the basis of carrier system consisting of connected sandstone bodies, of sand-bodies connected with other carriers, such as faults and/or unconformities. How do we understand sandstone carrier beyond the traditional reservoirs concept? How could we characterize quantitatively this kind of carriers for petroleum migration? Such subjects are important and difficult contents in dynamic studies on hydrocarbon migration and accumulation. Sandstone carrier of Chang 8 member in Longdong area of Ordos Basin is selected as the research target in this thesis. Through conducting integrated reservoir analysis on many single wells, the correlation between single sandstone thickness and oil thickness seems good. Sketch sandstone is defined in this thesis as the principal part of carrier based on systematical analysis on lithology and sandstone thickness. Geometry connectivity of sandstone bodies was identified by the spatial superposition among them and was proved by the oil property features in oilfields. The connectivity between sandstone carriers is also hydrodynamically studied by observing and analyzed various diagenetic phenomena, especially the authigenic minerals and their forming sequence. The results were used to characterize transporting capability of sandstone carriers during the key petroleum migration periods. It was found that compaction and cementation are main causes to reduce pore space, and resolution may but not so importantly increases pore space after the occurrence of first migration. The cements of ferrocalcite and kiesel seem like the efficient index to demonstrate the hydraulic connection among sandy bodies. Diagenetic sequence and its relationship with petroleum migration phases are analyzed. Sandstone carrier of Chang 8 member was then characterized by studying their pore space and permeable properties. The results show an average porosity and permeability of Chang 8 carriers are respectively 8% and 0.50md, belongs to low porosity - low permeability reservoirs. Further, the physical properties of Chang 81 member are commonly better than those of Chang 82 member. Methods to reconstruct property of sandstone carrier during petroleum migration phase (late Jurassic) are built based on diagenetic sequence. Planal porosity, porosity and permeability of sandstone carrier in this period are statistically analyzed. One combining index - product of thickness and ancient porosity - is selected as the idea parameter to characterize sandstone carrier of late Jurassic after contrast with other parameters. Reservoirs of Chang 8 member in Longdong area are lithological reservoir controlled by sand body in which oil layers in middle part are clamped with dry layers in upper and lower parts, in a sandwich way. Based a newly proposed “migration-diagensis-remigration” model in low permeability sandstone of Chang 8 member in Longdong area, oil migration and accumulation processes during different periods are simulated with the reconstructed sandstone carriers system. Results match well with current reservoir distributions. Finally, suggestions for next favorable exploration areas are given based on all research achievements.