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.

准噶尔盆地西北缘三叠系层序地层及有利勘探目标选择

Based on outcrop, borehole, seismic and regional geological data, the sequence stratigraphy, sedimentary facies of the Triassic in the western margin of the Zhugaer basin was studied, and favorable exploration target was forecasted. The major achievements include: (1) the Triassic in the western margin of the Zhugaer basin can be divided into 1 second-order sequence and 5 third-order sequences, which are, in ascending order, TSQ1, TSQ2, TSQ3, TSQ4, and TSQ5. TSQ1 is equivolent to Baikouquan formation, TSQ2 is equivolent to lower Kelamayi formation, TSQ3 is equivolent to upper Kelamai formation, TSQ4 is equivolent to lower and middle Baijiantan formation, and TSQ5 is equivolent to upper Baijiantan formation. Each sequence is divided into transgressive and regressive system tracts. Thus the sequence correlation framework is established. (2) The factors controlling development of sequences are analyzed, and it is believed that tectonic is the major controlling factor. Model of sequence development is summarized. (3)Through study on sedimentary facies, 6 types of facies are recognized: alluvial fan, fan delta, braided river, braided delta, delta and lake. Their microfacies are also recognized. In this study, it is proposed that the upper and lower Kelamayi formation（TSQ2、 TSQ3）is deposited by braided river instead of alluvial fan. This conclusion is of important theoretical and practical significance.(4) The sedimentary facies map of each sequence is compiled, and the sedimentary facies developed in each sequence is determined. In TSQ1, the sedimentary facies developed is alluvial fan and fan delta. In TSQ2, the sedimentary facies developed is mainly alluvial fan and fan delta in the north, and braided river and braided delta in the south. In TSQ3, the sedimentary facies developed is mainly braided river and braided delta. In TSQ4, the sedimentary facies developed is mainly braided delta in the north, and meandering delta in the south. In TSQ5, the sedimentary facies developed is mainly braided river and braided delta. (5) In the framework of sequence stratigrahpy, favorable areas for concealed traps are forecasted, and different types of traps are developed in different system tracts. (6) Favorable areas for future exploration are predicted.

北天山新生代构造演化与古环境演变

The Tianshan Mountains is located about 1000-2000 km north of the India-Asia suture and is the most outstanding topography in central Asia, with transmeridional length of nearly 2500 km, north-southern wideness of ~ 300-500 km, peaks exceeding 7000 m above sea level (asl.), and average altitude of over 4000 m asl. Much of the modern relief of the Tianshan Range is a result of contraction driven by the collision of the India subcontinent with the southern margin of Asia, which began in early Tertiary and continues today. Understanding where, when and how the deformation of the Tianshan Mountains occurred is essential to decipher the mechanism of intracontinental tectonics, the process of foreland basin evolution and mountain building, and the history of climate change in central Asia. In order to better constrain the Cenozoic building history of the Tianshan Mountains and the climate change in the southern margin of the Junggar Basin, we carried out multiple studies of magnetostratigraphy, sedimentology, and stable isotopes of paleosol carbonate at the Jingou River section, which is located at the Huoerguosi anticline, the westernest one of the second folds and thrust faults zone in the northern piedmont of the Tianshan Mountains. The Jingou River section with a thickness of about 4160 m is continuous in deposits according to the observed gradual change in sedimentary environments and can be divided into five formations: Anjihaihe, Shawan, Taxihe, Dushanzi and Xiyu in upward sequence. Characteristic remamences were isolated by progressive thermal demagnetization, generally between 300 and 680℃. A total of 1133 out of 1607 samples yielded well-defined ChRMs and were used to establish the magnetostratigraphic column of a 3270-m-thick section from the exposed base of the Anjihaihe Formation to the middle of the Xiyu Formation. Two vertebrate fossil sites and a good correlation with the CK95 geomagnetic polarity time scale suggest that the section was deposited from ~30.5 to ~4.6 Ma and the age of the top of the Xiyu formation is ~2.6 Ma based on an extrapolation of the sedimentation rates. A plot of magnetostratigraphic age vs. height at the Jingou River section shows that significant increases in sedimentation rates as well as notable changes in depositional environments occurred at ~26-22.5 Ma, ~13-11 Ma and ~7 Ma, which represent the initial uplift of the Tianshan Mountains and two subsequent rapid uplift events. In addition, changes in sedimentation rates display characteristic alternations between increases and decreases, which probably indicate that the uplift of the Tianshan Mountains was episodic. We discussed the history of C4 biomass and climatic conditions in the southern margin of the Junggur Basin using the stable carbon and oxygen isotope composition of paleosol carbonates from the Jingou River section during ~17.5-6.5 Ma. The δ13C values indicate that the proportion of C4 biomass was uniform and moderate (15-20 %) during the interval of ~17.5-6.5 Ma. We proposed three hypotheses for this pattern of C4 biomass: (1) counteraction of two opposed factors (global cooling since ~15 Ma and thereafter increased dry and seasonality in central Asia) controlling the growth of C4 grasses, (2) variability in abundance of C3 grasses relative to C3 trees and shrubs if vegetation had ever changed in ecosystems, and (3) the higher latitude of the studied region. The δ18O values show a stepwise negative trend since ~13 Ma which may be attributed to three factors: (1) the temperature decreasing gradually after the middle Miocene (~15 Ma), (2) the increasing contribution of the moistures carried by the polar air masses from the Arctic Ocean to precipitation, and (3) the gradual retreat westward and disappearance of the Paratethys Ocean. Among them, which one played a more important role will need further study of the paleoclimate in central Asia.

准噶尔盆地南缘台13井区侏罗系油藏表征与建模

Junggar Basin has a large amount of recoverable reserves, However, due to the unfavorable factors, such as bad seismic data quality, complex structure with many faults and less wells, the exploration of oil and gas is still relatively limited, so advanced theoretical guidance and effective technical supports are desirable. Based on the theories of sedimentology, as well as comprehensive studies of outcrops, seismic data, drilling data and setting of this area, the paper establishes the isochronous correlation framework, and analyzes the sedimentary facies types and provenance direction, and obtains the profile and plain maps of the sedimentary facies combined with the logging constrained inversion. Then the paper analyzes the reservoir controlling factors, reservoir lithology attribute, 4-property relationship and sensibility based on the sedimentary facies research, and sets up a 3D geological model using facies controlled modeling. Finally, the paper optimizes some target areas with the conclusions of reservoir, structure and reservoir formation.Firstly, the paper establishs the isochronous correlation framework by the seismic data, drilling data and setting of this area. The sedimentary facies in Tai13 well block are braided river and meandering river according to the analysis of the lithology attribute, logging facies and sedimentary structure attribute of outcrop. The concept of “wetland” is put forward for the first time. The provenance direction of Badaowan and Qigu formation is obtained by the geology setting, sedimentary setting and paleocurrent direction. The paper obtains the profile and plain maps of the sedimentary facies from the sand value of the wells and the sand thickness maps from the logging constrained inversion. Then, this paper takes characteristics and control factors of the Jurassic reservoirs analysis on thin section observation, scanning transmission electron microscope observation and find out the petrology characteristics of reservoir, space types of reservoir and lithofacies division. In this area, primary pores dominate in the reservoir pores, which believed that sedimentation played the most important roles of the reservoir quality and diagenesis is the minor factor influencing secondary porosity. Using stochastic modeling technique，the paper builds quantitative 3-D reservoir Parameter. Finally, combined the study of structure and reservoir formation, the reservoir distribution regularity is concluded: (a) structures control the reservoir formation and accumulation. (b) Locating in the favorable sedimentary facies belt. And the area which meets these conditions mentioned above is a good destination for exploration.

鄂尔多斯盆地志丹地区延长组储层综合评价

Sedimentary provenance direction，sedimentary facies，reservoir geological characteristic，pore structure； physical property characteristic，reservoir classification and evaluation ，forthermore，favorable area area are forecasted of Yanchang formation in ZhiDan region， by mainly study on the data of field section observation ，core observation, well logging explaination and routine microscope slice identification，scanning Electron Microscope and reservoir analysis of lithology and physical property , Under the guidance of such advanced theories and methods as sedimentology，reservoir sedimentology，lithological oil pool and so on，in the thesis. The following fruits are mainly achieved in this paper： Yanchang formation stratum is divided and correlated in this entire region， and the characteristic of oil layer unit is detailed discussed , respectively. According to main marker bed and supplementary ones.and research result shows that the source of provenance direction during Yanchang Formation mianly is north-east. Delta and lake are mainly developed in study area ，sub-facies and micro-facies are divided，distribution of sedimentary micro-facies in plane and palaeogeographic evolution are described，and gentle slope type- shallow water delta depositional model is established. Fine-grain arkose sandstone is the main reservoir，and which have experienced such different degree diagenesis as compaction, cementation, replacement and dissolution, and in which compaction and cementation are mainly factors to reduce sandstone physical property and dissolution effectively improved physical property during burial diagenesis procedure. All reservoirs of Yanchang Formation have entered A period of late diagenetic stage according to scheme of diagenesis period division . Intergranular porosity，dissolution porosity，fissure porosity are main pore types. And porosity structure are analyse by mercury penetration capillary pressure parameter，fine-shortness type and fine- length throat type are mainly developed. as a whole，the reservoir， with the characteristic of porosity and permeability altering apparently，strong inhomogeneity ， is a medium- porosity and medium permeability one. In plane，higher- porosity and higher-permeability are corresponded well with distributary channel area， physical property and inhomogeneity are affected by both deposition and diagenesis，and distributary channel and underwater distributary channel are favorable facies . According to such characteristic as lithology，physical property，pore structure ，diagenesis and sandstone distribution, the sandy reservoir can be classified 4 types, and the main sandy in every oil layer unit are evaluated according to the standard. The analysis result of petroleum concentration rule shows that Yanchang Formation are with not only favourable oil source rock，reservoir，covering combination ，but also good entrapment condition in study area. Lithology and structure-lithology oil pool are mainly developed ，based on condition of favorable reservoir developments，accounting for deliverability and sandstone superface elevation，zone of profitabilitis are forecasted.

鄂尔多斯盆地三叠系延长组特低渗透储层分类评价

On the basis of the character of sedimentation and reservoir researching as well as diagenesis, using conventional and update testing measures, classificati-on and evaluation of the tesla low permeability reservoir in Ordos Basin is pr-esented. From Chang 8 to Chang 4+5 oil formations, four facies developed, includi-ng alluvial fan facies, delta facies, lake facies as well as density current. They were controlled by the northeastern, the southwest, the southern and the northwestern provenances. Distributary channel underwater and mouth bar of delta fr-ont are the main reservoirs. Detrital component has the different character in s-outh and in north. Sedimentary system in the northeastern part has more felds-par and less quartz. Sedimentary system in the southern part has more quartz and less feldspar. Because of sedimentation and diagenesis, the oil formations in region of interest formed the different features of pore array of the tesla l-ow permeability reservoirs. After researching, it is found that the active porosity and the main throat radius of Chang 4+5 are the highest, and they are positive correlation with per-meability. The exponent of flowing interval falls in the sortorder: Chang 8, Chang 4+5, Chang 6, Chang 7. Using clustering procedure and quaternion, the reservoirs of Yanchang for-mation in Ordos Basin are divided into five types. Ⅰ-good reservoirs and Ⅱ-appreciably good reservoirs occur in distributary channel and mouth bar. Ⅲ-poor reservoirs and Ⅳ-poorer reservoirs exist in natural levee, crevasse splay under-water and turbidity fan. It is forecasted that the oil area in Ⅰ-good reservoirs is about 4336.68 square kilometers, and the oil area in Ⅱ-appreciably good reservoirs is 28013.28 square kilometers or so, and the oil area in Ⅲ-poor rese-rvoirs is 28538.05 square kilometers more or less.

安塞油田三叠系延长组长10油层组沉积相研究

Ordos basin is a large-scale craton overlapping basin, which locates in western North China platform and possesses abundant hydrocarbon resources. Ansai area in 2007 to extend the head of Chang10 of Yangchang Formation has made breakthrough progress in the region, long a high of Gao52 was Chang10 industrial oil flow, for oil exploration Ansai Oil Field opened a new chapter. in 2008, high of Gao52, Wang519, Gao34 producing wells area of building and found the existence of Chang10 great potential for the discovery of Chang10 Reservoir, Ansai Oil Field for a new direction, showing a good exploration development prospects.The study of occurrence and distribution features of hydrocarbon should be made by new theories and evolutions of sedimentology, sequence stratigraphy, reservoir sedimentology and petroleum geology form different angles on the base of regional geology background. Ansai Oil Field is in mid Shanbei Slope, which is a considerable producing zone of Ordos basin. Chang10 of Yangchang Formation is an important oil-bearing series, which sedimentary formation was formed in Indosinian orogeny, Late Triassic, sedimentary background is a momentary uplifting in Ordos basin, and exploration and exploitation of hydrocarbon in this area is very important. To further descripte disciplinarian of accumulation hydrocarbon, carefully study on sedimentary facies, reservoir type and disciplinarian of accumulation hydrocarbon of Chang10 of Yangchang Formation in study area is needed. By collecting date of field profile, outcrop, core and many other geological, through sedimentary and oil geological analysis, sedimentary facies types were identified, distributing of sedimentary facies and extension of sand body were analyzed too. Finally, the main controlling factors of hydrocarbon and the favorable areas were found out by deeply studying sedimentary system and disciplinarian of accumulation oil&gas in Chang10 of Yangchang Formation, Late Triassic in Ansai Oil Field. Chang10 of Yangchang Formation is main study formation, which is divided into three members (Chang101, Chang102 and Chang103), Chang101 is subdivided into three (Chang1011, Chang1012and Chang1013) reservoirs. By defining Layered borderline between every member and detailed describing rock and electro characteristic, member zonation become more reasonable and accurate also sedimentary facies and disciplinarian of accumulation oil&gas in study area are confirmed Through researching sedimentary facies, reservoir sand and hydrocarbon migration, accumulation, distribution, hydrocarbon accumulation models of Chang10 of Yangchang Formation in study area is pointed out, which is lithologic hydrocarbon reservoir and tectonic-lithologic hydrocarbon reservoir. Different play is formed by different processes and factors. Through analysis of reservoir property, trap type and accumulation model, several favorable exploration areas can be found out in Chang 10 reservoirs （Chang1011, Chang1012and Chang1013） of the Ansai Oil Field.

松辽盆地南部大情字井地区CO2埋存体地质格架及储层建模

Increasing attentions have been paid to the subsurface geological storage for CO2 in view of the huge storage capacity of subsurface reservoirs. The basic requirement for subsurface CO2 storage is that the CO2 should be sequestrated as supercritical fluids (physical trapping), which may also interact with ambient reservoir rocks and formation waters, forming new minerals (chemical trapping). In order to the effective, durable and safe storage for CO2, enough storage space and stable sealing caprock with strong sealing capacity are necessitated, in an appropriate geological framework. Up till now, hydrocarbon reservoirs are to the most valid and appropriate CO2 storage container, which is well proven as the favorable compartment with huge storage capacity and sealing condition. The thesis focuses on two principal issues related to the storage and sealing capacity of storage compartment for the Qingshankou and Yaojia formations in the Daqingzijing block, Southern Songliao Basin, which was selected as the pilot well site for CO2-EOR storage. In the operation area, three facies, including deltaic plain, deltaic front and subdeep-deep lake facies associations, are recognized, in which 11 subfacies such as subaqueous distributary channel, river- mouth bar, interdistributary bay, sheet sandbody, crevasse splay and overflooding plain are further identified. These subfacies are the basic genetic units in the reservoir and sealing rocks. These facies further comprise the retrogradational and progradational depositional cycles, which were formed base- level rise and fall, respectively. During the regressive or lake lowstand stage, various sands including some turbidites and fans occurred mostly at the bottom of the hinged slope. During the progradation stage, these sands became smaller in size and episodically stepped backwards upon the slope, with greatly expanded and deeped lake. However, most of Cretaceous strata in the study area, localized in the basin centre under this stage, are mainly composed of grey or grizzly siltstones and grey or dark grey mudstones intercalated with minor fine sandstones and purple mudstones. On the base of borehole and core data, these siltstones are widespread, thin from 10 to 50 m thick, good grain sorting, and have relative mature sedimentary structures with graded bedding and cross- lamination or crossbeds such as ripples, which reflect strong hydrodynamic causes. Due to late diagenesis, pores are not widespread in the reservoirs, especially the first member of Qingshankou formation. There are two types of pores: primary pore and secondary cores. The primary pores include intergranular pores and micropores, and the secondary pores include emposieus and fracture pores. Throat channels related to pores is also small and the radius of throat in the first, second and third member of Qingshankou formation is only 0.757 μm, 0.802 μm and 0.631 μm respectively. In addition, based on analyzing the probability plot according to frequency of occurrence of porosity and permeability, they appear single- peaked distribution, which reflects strong hetero- geneity. All these facts indicate that the conditions of physical property of reservoirs are not better. One reason may be provided to interpret this question is that physical property of reservoirs in the study area is strong controlled by the depositional microfacies. From the statistics, the average porosity and permeability of microfacies such as subaqueous distributary channel, channel mouth bar, turbidites, is more than 9 percent and 1md respectively. On the contrary, the average porosity and permeability of microfacies including sand sheet, flagstone and crevasse splay are less than 9 percent and 0.2md respectively. Basically, different hydrodynamic environment under different microfacies can decide different physical property. According to the reservoir models of the first member of Qingshankou formation in the No. well Hei47 block, the character of sedimentary according to the facies models is accord to regional disposition evolution. Meantime, the parameter models of physical property of reservoir indicate that low porosity and low permeability reservoirs widespread widely in the study area, but the sand reservoirs located in the channels are better than other places and they are the main sand reservoirs. The distribution and sealing ability of fault- fractures and caprock are the key aspects to evaluate the stable conditions of compartments to store CO2 in the study area. Based on the core observation, the fractures widespread in the study area, especially around the wells, and most of them are located in the first and second member of Qingshankou formation, almost very few in the third member of Qingshankou formation and Yaojia formation instead. In addition, analyzing the sealing ability of eleven faults in the three-dimensional area in the study area demonstrates that most of faults have strong sealing ability, especially in the No. well Hei56 and Qing90-27. To some extent, the sealing ability of faults in the No. well Hei49, Qing4-6 and Qing84-29 are worse than others. Besides, the deposition environment of most of formations in the study area belongs to moderately deep and deep lake facies, which undoubtedly take advantage to caprocks composed of mudstones widespread and large scale under this deposition environment. In the study area, these mudstones distribute widely in the third member of Qingshankou formation, Yaojia and Nenjiang formation. The effective thickness of mudstone is nearly ~550m on an average with few or simple faults and fractures. In addition, there are many reservoir beds with widely- developed insulated interbeds consist of mudstones or silty mudstone, which can be the valid barrier to CO2 upper movement or leakage through diffusion, dispersion and convection. Above all, the closed thick mud caprock with underdeveloped fractures and reservoir beds can be taken regard as the favorable caprocks to provide stable conditions to avoid CO2 leakage.

酒泉盆地酒东坳陷下白垩统储层特征及有利勘探方向研究

Jiuquan basin, located in the middle of the Hexizoulang, is one of the major important Mesozoic、cenozoic oil-gas bearing basin in the west of China. Jiuquan basin is composed of Jiuxi depression、Huahai-jinta depression and Jiudong depression. Basement of Jiudong depression is Silurian shallow metamorphic rock. Ying-er sag , focus of this study, is the biggest sag in Jiudong depression and the targeting study object is cretacic strata. Structure evolution and geological background were carefully studied in this research. A series of methods were applied to this research: values of oxygen and carbon isotope and trace elements analysis were used to recover salinity of the palae-lake water of the sag. The evolution and distribution of sedimentary faces were carefully studied. Also, various analysis and tests were made to study the diagenesis of the reservoir sandstones、porosity evolution and porosity distribution. All the studies indicate that sedimentary faces are main macroscopic factor controlling the reservoir quality; Compaction is the main factor destroying reservoir property. Carbonate cements greatly preserved the porosity in eodiagenesis because it had prevented significant early mechanical compaction and its dissolution in the late diagenesis generated secondary pores. Carbonate cements in the late diagenesis occluded primary porosity and played a negative role in the porosity preservation. Source of the carbonate cements were also preliminarily discussed. Feldspar grains and lithic fragments were dissolved by acid fluid and formed a great amount of secondary pores and developed the reservoir quality. Also, sedimentary-diagenesis zones were identified. On basis of these studies, Reservoir forming factors were studied. Keywords: Jiudong depression, sedimentary faces，reservoirs diagenesis reservoir evaluation，secondary pores

基于分形和统计理论的地层非均质研究

Basin-scale heterogeneity contains information about the traces of the past sedimentary cycle and tectonic process, and has been a major concern to geophysicists because of its importance in resource exploration and development. In this paper, the sonic data of 30 wells of Sulige field are used to inverse the power-law spectra slope and correlation length which are measures of the heterogeneity of the velocity of the log using fractal and statistic correlation methods. By taking the heterogeneity parameters of different wells interpolated, we get power law spectra slope and correlation length contours reflecting the stratum heterogeneity. Then using correlation and gradient, we inverse the transverse heterogeneity of Sulige field. Reservior-scale heterogeneity influnce the distribution of remaining oil and hydrocarbon accumulation. Using wavelet modulus maximum method to divide the sedimentary cycle using Gr data, therefore we can calculate the heterogeneity parameter in each layer of each log. Then we get the heterogeneity distribution of each layer of Sulige field. Finally, we analyze the relation between the signal sigularity and the strata heterogeneity, and get two different sigularity profiles in different areas.

鄂尔多斯盆地东部地区奥陶系马家沟组沉积相与储层特征研究

Ordos Basin is one of the primary bases for petroleum exploration in our country. A series of Ordovician large gas fields were discovered, which suggest that the Lower Paleozoic carbonate, especiallly for Ordovician carbonate rocks, preserve plenty of hydrocarbon resources. Well Longtong 1 is studied as the typical exploration well. Acorrding to the specific research on the type of lithology, texture, structure and sedimentary sequence in Ordovician Majiagou Formation as well as additional data from another 20 wells, the sedimentary model has been built in Majiagou Formation. The sedimentary characteristics for each Member in Majiagou Formaiton and the feature of distribution are well understood as below: It suggests that period of Member 1, Member 3 and Member 5 in Majiagou Formation characterize with dry and hot climate as well as drop of the sea level. The area of Well Longtan 1 in the eastern basin is abundant of platform evaporite lithofacies with the depositional anhyrock and salt rock, whereas yield a suite of dolomite intercalated by the thin layers of anhyrock from the anhyrcok-dolomite platform sediment. It deposits muddy dolomite, dolomitic limestone and fine-grain dolomite in limestone-dolomite platform and restricted sea. During the stage of Member 2 and Member 4 in Majiagou Formation, the climate is wet and hot with increasing sea level. The study region occurs limestone with little dolomite in the open sea environment; but the margin area is the restricted sea settings with interbeding dolomite and limestone. Based on the thin section identification, element and isotope analysis as well as the study of texture and structure, it sugguests that the main reserviors are dolomite while the gypsum are major cap rocks. The Member 2 in Majiagou Formation is both the source rocks and the resveroirs; gypsum rocks widely occur in Member 3 as the better cap; similar to the Member 2, the Member 4 in Majiagou Formation is both the source rocks and the resveroirs; there are two source-reservoir-cap assemblages in the Member 5 alone and the cap is gypsum with high quality and great thickness, which is a favorite source-reservoir-cap assemblage.