972 resultados para pier cap
Resumo:
After the half century exploration, previous scholar evaluating thought that there were poor Petro-Geological conditions in Chepaizi area of Zhungar basin. Recently, with the great discovery in the Well Pai2,the study on the subtle reservoir in Chepaizi area are gained great attentions by the scholars all over the world day by day. Chepaizi uplift is a inherited palaeohigh, and its structural traps are undeveloped. The sedimentary faces of Shawan Formation of Neogene have apron type of alluvial fan, alluvial plain, alluvial fan delta, salt lake, shore and shallow lake and so on. The sedimentary faces of Shawan Formation of Well Pai2 is alluvial fan delta and shore and shallow lake, the first part of Shawan Formation(N1s1) is the main target for exploration. Using the seismic forward, property analysis, spectral factorization, logging restrain inversion and so on, The spatial distribution of the sand reservoir and its hydrocarbon, predicted and 20 lithology traps in 5 substratums were carried out. The traps have a total areal of 107.13 Km2, and the geological reserves in it can reach 8703.7×104t. After comprehensive research on the trap,reservoir, cap and the condition of the hydrocarbon accumulation, it is considered that the elements of hydrocarbon in Chepaizi area are various. Because it can’t generate hydrocarbon, the oil and gas conducting and accumulation are the most important factors in this area, and the validity of the lithology traps in monoclinal is another important factor. Research indicates that the master control factor of the subtle reservoir in Chepaizi area is fault and sand. The sand of beach and sandbar provide the space for the hydrocarbon accumulation, the fault provides the migration channel for the hydrocarbon. Most faults have a characteristics of up seal and the down open, which not only can conduct hydrocarbon, but also can prevent hydrocarbon overtopping, therefore the effect trap is results of good match of fault and sand.
Resumo:
The anchorages are unparalleled structures only in a suspension bridge, and as main bearing facilities, play an important role in connecting the superstructures and the ground. The tunnel anchorage, as one alternative type of the anchorages, has more advantages over its counterpart, the gravity anchorage. With the tunnel anchorages adopted, not only can surface excavation be reduced to protect the environment, and natural condition of the rock be utilized and potential bearing capacity of surrounding rock be mobilized to save engineering cost, but also the technological predominance of auxiliary engineering measures, such as prestressed concrete, anchoring piles, rock anchors and collar beam between the two separated anchorages, can be easily cooperated to work together harmoniously under the circumstances of poor rock quality. There are plentiful high mountains and deep canyons in west part of China, and long-span bridge construction is inevitably encountered in order to realize leapfrogging development of the transportation infrastructure. Western mountainous areas usually possess the conditions for constructing tunnel anchorages, and therefore, the tunnel anchorages, which are conformed to the conception of resource conservative and sustainable society, extremely have application and popularization value in western underdeveloped region. The scientific and technological problem about the design, construction and operation of tunnel anchorages should be further investigated. Combining the engineering of western tunnel anchorages for the Balinghe Suspension Bridge, this paper probed into the survey method and in-situ test method for tunnel anchorages, scientific rock quality evaluation of surrounding rock to provide reasonable physical and mechanical parameters for design, construction and operation of tunnel anchorages, bearing capacity estimation for tunnel anchorage, deformation prediction of the anchorage-rockmass system, tunnel-anchorage slope stability analysis and the evaluation of excavation stability and degree of safety of the anchorage tunnel. The following outcomes were obtained: 1. Materials of tunnel anchorages of suspension bridge built (and in progress) at home and abroad were systematically sorted out, with the engineering geological condition and geomechanical property of surrounding rock around the anchorage tunnel, the design size of anchorages and the construction method of anchorage tunnel paid more emphasis on, to unveil the internal relationship between the engineering geological conditions of surrounding rock and the design size and axis angle of anchorages and provide references for future design, construction and study of tunnel anchorages. 2. Physical and mechanical parameters were recommended based on three domestic and foreign methods of rock quality evaluation. 3. In-situ tests, adopting the back-thrust method, of two kinds of reduced scale model, 1/30 and 1/20, for the tunnel anchorages were conducted in the declining exploration drift with rock mass at the test depth being the same as surrounding rock around real anchorages, and reliable field rockmass displacement data were acquired. Attenuation relation between the increment of distance from the anchorage and the decrement of rockmass displacement under maximum test load, and influential scope suffered by anchorage load were obtained. 4. Using similarity theory, the magnitude of real anchorage and rockmass displacement under design load and degree of safety of the anchorage system were deduced. Furthermore, inversion analysis to deformation modulus of slightly weathered dolomite rock, the surrounding rock of anchorage tunnel, was performed by the means of numerical simulation. 5. The influential law of the geometrical size to the limit bearing capacity of tunnel anchorage was studied. 6. Based on engineering geological survey data, accounting for the combination of strata layer and adverse discontinuities, the failure patterns of tunnel anchorage slope were divided into three modes: sliding of splay saddle pier slope, superficial-layer slippage, and deep-layer slippage. Using virtual work principle and taking anchorage load in account, the stability of the three kinds of failure patterns were analyzed in detail. 7. The step-by-step excavation of anchorage tunnel, the numerical overload and the staged decrement of rock strength parameters were numerically simulated to evaluate the excavation stability of surrounding rock around anchorage tunnel, the overload performance of tunnel anchorage, and the safety margin of strength parameters of the surrounding rock.
Resumo:
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.
Resumo:
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.
Resumo:
Complex fault block reservoir is very important type in chinese oilfield.The reservoir have for many years and it has been the important issue of oil-gas exploration and development in china that how to increase reserves and production. Therefore,taking the Pucheng-oil field as an example, the article intensive study the geologic feature of oil pool, correctly recognize the rule of oil-gas accumulation and based on the fine representation of the characteristic of reservoir, research the remaining oil in high developed area,which is important for progressive exploratioon and development and taping the remaining oil. The article multipurpose uses the data of geology,drilling,wellloging, analysis and assay and so on, under the guidance multi-disciplinary theory, intensify the comprehension of the geologic feature of oil pool in high developed oil field. Based on the high-resolution sequence stratigraphic framework ,the article points out that Es_2 upper 2+3 reservoir in the south area of Pucheng oilfield is in the depositional environment of Terminal Fan, which has constant supply of sedimentary source ,and build the sedimentation model. Studies have shown that the major reservoir in work area is the distributary channel sandbody in central Sub-facies of Terminal Fan,secondary is both lateral accretion sandbodies of channel sands,nearby and far away from the channel overflowing sandbodies in front of the fan. The article analyze the effect of depth of burial of the reservoir, sandstone structure, strata pressure and bioturbate structure on control action of physical property for reservoir and indicate that deposition and diagenesis are major controlling factors.By building the model of reservoir heterogeneity, the article show the magnitude of reservoir heterogeneity ,the genesis and identification mark of Interlayer and build the the model of interlayer. in this area the vertical distribution of interlayer is complicated,but the intraed interlayer distribute steady. Thick interlayer is steady and the thin is relatively spreaded. By building models of fault sealing,stress field and fluid potential field of the south of the pucheng oil field, the regular pattern of fluid migration and accumulation runs out. By researching the elements of oil accumulation, migration pathway and accumulation period with quantification and semiquantitative methods,we bulit the oil-gas reservoir-forming mode of the south of the pucheng oil field,which will be the foundation of the rolling exploratory development in the future. We promulgated the master control element and the rule of distribution of the remaining oil with the upside 2+3 oil layer in shaer in the south of the pucheng oil field as an example.In this area, the formation and the distribution of the remaining oil is controled by the sedimentary microfacies, reservoir heterogeneity,fault and reservoir engineering. The remaining oil is concentrated in the vicinity of the gas cap, updip of the fault block and the area with incomplete flooding. Remaining oil saturation in some area can get 50%, so there are many places in which we can enhance oil recovery.
Resumo:
High resolution geochemical analysis of Ediacaran Doushantuo Formation deposits in eastern Gorges area, including carbon and sulfur isotope compositions, trace elements, rare earth elements, and so on, show a whole panorama of the oceanic environment in Ediacaran Doushantuo Formation. The deposits of Doushantuo II recorded consistent δ13Corg values and variable δ13Ccarb values, which suggets that it is strongly redox stratified in Doushantuo ocean, and there is a large DOC reservior in the deep ocean. The redox state of Doushantuo ocean in Yangtze area was not steady. The movement of chemocline was concerned with the transgression and/or regression. During the transgression, raising sea level and upwelling with anoxic deep water would cause the ocean anoxic; during the regression, declining sea level and weathered sulfate input would cause the suface ocean becoming oxic. The oxidations of this DOC reservior would caused negative δ13C excurions in Doushantuo Formation. Comparing with oceanic redox states and fossils productivity, we found that the stratum with high biologic productivity and diversity did not indicated oxic conditions. In the opposite, these stratum recorded anoxic conditions. We suggeste that it would be relatived to burial and preservation of fossils, because anoxic conditions are in favor of burial and preservation of fossils. It is proved that methane seep occurred at the base of Duoshantuo cap carbonate. However, comparing cap carbonate with seep carbonate, we found that oxidation of methan and the post-diagenesis could not derictely result in cap carbonate deoposition. Cap carbonate would be derived from the high level CO2 in atomosphere.
Resumo:
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.
Resumo:
As a kind of special lithologic ones, Igneous rock oil and gas pool is more and more paid attention, and it has different forming condition and distribution from conventional ones, such as various terrane distribution types, serious reservoir anisotropy, complicated hydrocarbon-bearing, so there is not successful experience to follow for exploration and development of this complex subtle oil and gas pool at present. For an example of Igneous oil and gas pool of Luo151 area in Zhanhua seg, Eastern China, this article study the difficult problem, including petrologic nd lithofacies analysis, Origin, invasion age and times of Igneous rock, reservoir anisotropy, Geological Modeling, Igneous reservoir synthesis evaluation. forming condition and distribution are studied synthetically, and an integrated method to predict igneous rock oil and gas pool is formed, which is evaluated by using development data. The Igneous rock is mainly diabase construction in Luo151 area of Zhanhua Sag, and petrologic types include carbonaceous slate, hornfels, and diabases. Based on analyzing synthetically petrologic component, texture and construct, 4 lithofacies zones, such as carbonaceous slate subfacies, hornfels subfacies containing cordierite and grammite, border subfacies and central subfacies, are divided in the diabase and wall rock. By studying on isotopic chronology, terrane configuration and imaging logging data, the diabase intrusion in Zhanhua Sag is formed by tholeiite magma emplacing in Shahejie formation stratum on the rift tension background Lower Tertiary in North China. The diabase intrusion of Luo151 is composed possibly of three periods magma emplacement. There is serious anisotropy in the diabase reservoirs of Luo151 in Zhanhua Sag. Fracture is primary reservoir space, which dominated by tensile fracture in high obliquity, and the fracture zones are mainly developed round joint belt of igneous rock and wall rock and position of terrane thickness changing rapidly. The generation materials of the reservoirs in Luo151 igneous oil pools consist of Intergranular micropore hornfels, condensate blowhole-solution void diabase condensate edge, the edge and center of the condensate seam diabase, of which are divided into horizontal, vertical and reticulated cracks according fracture occurrence. Based on the above research, a conceptual model of igneous rock reservoir is generated, which is vertically divided into 4 belts and horizontally 3 areas. It is built for the first time that classification evaluation pattern of igneous rock reservoir in this area, and 3 key wells are evaluated. The diabase construction is divided into grammite hornfels micropore type and diabase porous-fracture type reservoirs. The heavy mudstone layers in Third Member of Shahejie formation (Es3) provide favorable hydrocarbon source rock and cap formation, diabase and hornfels belts serve as reservoirs, faults and microcracks in the wall rocks as type pathways for oil and gas migration. The time of diabase invasion was about in the later deposition period of Dongying Formation and the middle of that of Guantao Formation, the oil generated from oil source rock of Es3 in the period of the Minghuazhen formation and is earlier more than the period of diabase oil trap and porous space forming. Based on geological and seismic data, the horizon of igneous rocks is demarcated accurately by using VSP and synthetic seismogram, and the shape distribution and continuity of igneous rocks are determined by using cross-hole seismic technology. The reservoir capability is predicted by using logging constraining inversion and neural network technology. An integrated method to predict igneous rock oil and gas pool is formed. The study is appraised by using development data. The result show the reservoir conceptual model can guide the exploration and development of oil pool, and the integrated method yielded marked results in the production.
Resumo:
Jiyang & Changwei depressions are two neighboring depressions in Bahai Bay Basin, the famous oil rich basin in East China. The exploration activities in the past 40 years has proved that, within the basins, there exists not only plentiful sandstone hydrocarbon reservoirs (conventional), but also abundant special reservoirs as igneous rock, mudstone and conglomerate ones which have been knowing as the unconventional in the past, and with the prospecting activity is getting more and more detailed, the unconventional reservoirs are also getting more and more important for further resources, among which, the igneous lithological reservoir be of significance as a new research and exploration area. The purpose of this paper is, with the historical researches and data as base, the System Theory, Practice Theory and Modern Comprehensive Petroleum Geology Theory as guide, the theoretical and practice break through as the goal, and the existing problems in the past as the break through direction, to explore and establish a valid reservoir formation and distribution models for igneous strata in the profile of the eastern faulted basins. After investigating the distribution of the igneous rocks and review the history of the igneous rocks reservoirs in basins, the author focused on the following issues and correspondingly the following progresses have been made: 1.Come to a new basin evolution and structure model named "Combined-Basin-bodies Model" for Jiyang even Eastern faulted basins based on the study on the origin and evolution of Jiyang & Changwei basins, depending on this model, every faulted basin in the Bo-hai Bay Basin is consisted of three Basin-Bodies including the Lower (Mesozoic), Middle (Early Tertiary) and the Upper (Late Tertiary) Bodies, each evolved in different geo-stress setting and with different basin trend, shape and igneous-sedimentary buildings system, and from this one to next one, the basin experienced a kind of process named "shape changing" and "Style changing". 2. Supposed a serious of new realizations as follows (1) There were "multi-level magma sources" including Upper mantel and the Lower, Middle and even the Upper Shell magma Chambers in the historical Magma Processes in the basins; (2) There were "multi-magma accessing or pass" from the first level (Mantel faults) to the second, third and fourth levels (that is the different levels of fault in the basin sediment strata) worked in the geo-historical and magma processes; (3) Three tectonic magma cycles and more periods have been recognized those are matched with the "Basin -body-Model" and (4)The geo-historical magma processes were non-homogeneous in time and space scale and so the magma rocks distributed in "zones" or "belts". 3. The study of magma process's effect on basin petroleum conditions have been made and the following new conclusions were reached: (1) the eruptive rocks were tend to be matched with the "caped source rock", and the magma process were favorable to the maturing of the source rocks. (2) The magma process were fruitful to the accumulation of the non-hydrocarbon reservoirs however a over magma process may damage the grade of resource rock; (3) Eruptive activity provided a fruitful environment for the formation of such new reservoir rocks as "co-eruptive turbidity sandstones" and "thermal water carbonate rocks" and the intrusive process can lead to the origin of "metamorphism rock reservoir"; (4) even if the intrusive process may cause the cap rock broken, the late Tertiary intrusive rocks may indeed provide the lateral seal and act as the cap rock locally even regionally. All above progresses are valuable for reconstructing the magma-sedimentary process history and enriching the theory system of modem petroleum geology. 4. A systematic classification system has been provided and the dominating factors for the origin and distribution of igneous rock reservoirs have been worked out based on the systematic case studies, which are as follows: (1) The classification is given based on multi-factors as the origin type, litho-phase, type of reservoir pore, reservoir ability etc., (2) Each type of reservoir was characterized in a detailed way; (3) There are 7 factors dominated the intrusive reservoir's characteristics including depth of intrusion, litho-facies of surrounding rocks, thickness of intrusive rock, intrusive facies, frequency and size of the working faults, shape and tectonic deformation of rock, erosion strength of the rock and the time of the intrusion ect., in the contrast, 4 factors are for eruptive rocks as volcanic facies, frequency and size of the working faults, strength of erosion and the thermal water processing. 5. Several new concept including "reservoir litho-facies", "composite-volcanic facies" and "reservoir system" ect. Were suggested, based on which the following models were established: (1) A seven reservoir belts model for a intrusive unit profile and further more, (2) a three layers cubic model consisted of three layer as "metamorphic roe layer", "marginal layer" and "the core"; (3) A five zones vertical reservoir sequence model consisted of five litho-facies named A, B, C, D and E for a original lava unit and furthermore three models respectively for a erosion, subsidence and faulted lava unit; (4) A composite volcanic face model for a lava cone or a composite cone that is consisted of three facies as "crater and nearby face", "middle slope" and "far slope", among which, the middle slope face is the most potential reservoir area and producible for oil & gas. 6. The concept of "igneous reservoir" was redefined as the igneous, and then a new concept of "igneous reservoir system" was supposed which means the reservoir system consisted of igneous and associated non-igneous reservoirs, with non-hydrocarbon reservoir included. 7. The origin and distribution of igneous reservoir system were probed and generalized for the exploration applications, and origin models of the main reservoir sub-systems have been established including those of igneous, related non-igneous and non-hydrocarbon. For intrusive rocks, two reservoir formation models have been suggested, one is called "Original or Primary Model", and the another one is "Secondary Model"; Similarly, the eruptive rock reservoirs were divided in three types including "Highly Produced", "Moderately Produced" and "Lowly Produced" and accordingly their formation models were given off; the related non-igneous reservoir system was considered combination of eight reservoirs, among which some ones like the Above Anticline Trap are highly produced; Also, the non-hydrocarbon. Trap system including five kinds of traps was discussed. 8. The concept models for four reservoir systems were suggested, which include the intrusive system consisted of 7 kinds of traps, the land eruptive system with 6 traps, the under water eruptive system including 6 kinds of traps and the non-hydrocarbon system combined by 5 kinds of traps. In this part, the techniques for exploration of igneous reservoir system were also generalized and probed, and based on which and the geological progresses of this paper, the potential resources and distributions of every reservoir system was evaluated and about 186 millions of reserves and eight most potential non-hydrocarbon areas were predicted and outlined. The author believe that the igneous reservoir system is a very important exploration area and its study is only in its early stage, the framework of this paper should be filled with more detailed studies, and only along way, the exploration of igneous reservoir system can go into it's really effective stage.
Resumo:
Natural gas pays more important role in the society as clean fuel. Natural gas exploration has been enhanced in recent years in many countries. It also has prospective future in our country through "85" and "95" national research. Many big size gas fields have been discovered in different formations in different basins such as lower and upper Paleozoic in Erdos basin, Tertiary system in Kuche depression in Tarim basin, Triassic system in east of Sichuan basin. Because gas bearing basins had been experienced multiple tectogenesis. The characteristics of natural gases usually in one gas field are that they have multiple source rocks and are multiple maturities and formed in different ages. There has most difficult to research on the gas-rock correlation and mechanism of gas formation. Develop advanced techniques and methods and apply them to solve above problems is necessary. The research is focused on the critical techniques of geochemistry and physical simulation of gas-rock correlation and gas formation. The lists in the following are conclusions through research and lots of experiments. I 8 advanced techniques have been developed or improved about gas-rock correlation and gas migration, accumulation and formation. A series of geochemistry techniques has been developed about analyzing inclusion enclave. They are analyzing gas and liquid composition and biomarker and on-line individual carbon isotope composition in inclusion enclave. These techniques combing the inclusion homogeneous temperature can be applied to study on gas-rock correlation directly and gas migration, filling and formation ages. Technique of on-line determination individual gas carbon isotope composition in kerogen and bitumen thermal pyrolysis is developed. It is applied to determine the source of natural is kerogen thermal degradation or oil pyrolysis. Method of on-line determination individual gas carbon isotope composition in rock thermal simulation has being improved. Based on the "95"former research, on-line determination individual gas carbon isotope composition in different type of maceral and rocks thermal pyrolys is has been determined. The conclusion is that carbon isotope composition of benzene and toluene in homogenous texture kerogen thermal degradation is almost same at different maturity. By comparison, that in mixture type kerogen thermal pyrolysis jumps from step to step with the changes of maturity. This conclusion is a good proof of gas-rock dynamic correlation. 3. Biomarker of rock can be determined directly through research. It solves the problems such as long period preparing sample, light composition losing and sample contamination etc. It can be applied to research the character of source rock and mechanism of source rock expulsion and the path of hydrocarbon migration etc. 4. The process of hydrocarbon dynamic generation in source rock can be seen at every stage applying locating observation and thermal simulation of ESEM. The mechanism of hydrocarbon generation and expulsion in source rock is discussed according to the experiments. This technique is advanced in the world. 5. A sample injection system whose character is higher vacuum, lower leaks and lower blank has been built up to analyze inert gas. He,Ar,Kr and Xe can be determined continuously on one instrument and one injection. This is advanced in domestic. 7. Quality and quantity analysis of benzene ring compounds and phenolic compounds and determination of organic acid and aqueous gas analysis are applied to research the relationship between compounds in formation water and gas formation. This is another new idea to study the gas-rock correlation and gas formation. 8. Inclusion analysis data can be used to calculate the Paleo-fluid density, Paleo-geothermal gradient and Paleo-geopressure gradient and then to calculate the Paleo-fluid potential. It's also a new method to research the direction of hydrocarbon migration and accumulation. 9. Equipment of natural gas formation simulation is produced during the research to probe how the physical properties of rock affect the gas migration and accumulation and what efficiency of gas migrate and factors of gas formation and the models of different type of migration are. II study is focused on that if the source rocks of lower Paleozoic generated hydrocarbon and what the source rocks of weathered formation gas pool and the mechanism of gas formation are though many advanced techniques application. There are four conclusions. 1.The maturity of Majiagou formation source rocks is higher in south than that in north. There also have parts of the higher maturity in middle and east. Anomalous thermal pays important role in big size field formation in middle of basin. 2. The amount of gas generation in high-over maturity source rocks in lower Paleozoic is lager than that of most absorption of source rocks. Lower Paleozoic source rocks are effective source rocks. Universal bitumen exists in Ordovician source rocks to prove that Ordovician source rocks had generated hydrocarbon. Bitumen has some attribution to the middle gas pool formation. 3. Comprehensive gas-rock correlation says that natural gases of north, west, south of middle gas field of basin mainly come from lower Paleozoic source rocks. The attribution ratio of lower Paleozoic source rocks is 60%-70%. Natural gases of other areas mainly come from upper Paleozoic. The attribution ratio of upper Paleozoic source rocks is 70%. 4. Paleozoic gases migration phase of Erdos basin are also interesting. The relative abundance of gasoline aromatic is quite low especially toluene that of which is divided by that of methyl-cyclohexane is less than 0.2 in upper Paleozoic gas pool. The migration phase of upper Paleozoic gas may be aqueous phase. By comparison, the relative abundance of gasoline aromatic is higher in lower Paleozoic gas. The distribution character of gasoline gas is similar with that in source rock thermal simulation. The migration phase of it may be free phase. IH Comprehensive gas-rock correlation is also processed in Kuche depression Tarim basin. The mechanism of gas formation is probed and the gas formation model has been built up. Four conclusions list below. 1. Gases in Kuche depression come from Triassic-Jurassic coal-measure source rocks. They are high-over maturity. Comparatively, the highest maturity area is Kelasu, next is Dabei area, Yinan area. 2. Kerogen thermal degradation is main reason of the dry gas in Kuche depression. Small part of dry gas comes from oil pyrolysis. VI 3.The K12 natural gas lays out some of hydro-gas character. Oil dissolved in the gas. Hydro-gas is also a factor making the gas drier and carbon isotope composition heavier. 4. The mechanism and genesis of KL2 gas pool list as below. Overpressure has being existed in Triassic-Jurassic source rocks since Keche period. Natural gases were expulsed by episode style from overpressure source rocks. Hetero-face was main migration style of gas, oil and water at that time. The fluids transferred the pressure of source rocks when they migrated and then separated when they got in reservoir. After that, natural gas migrated up and accumulated and formed with the techno-genesis. Tectonic extrusion made the natural gas overpressure continuously. When the pressure was up to the critical pressure, the C6-C7 composition in natural gas changed. The results were that relative abundance of alkane and aromatic decreased while cycloalkane and isoparaffin increased. There was lots of natural gas filling during every tectonic. The main factors of overpressure of natural gas were tectonic extrusion and fluid transferring pressure of source rocks. Well preservation was also important in the KL2 gas pool formation. The reserves of gas can satisfy the need of pipeline where is from west to east. IV A good idea of natural gas migration and accumulation modeling whose apparent character is real core and formation condition is suggested to model the physical process of gas formation. Following is the modeling results. 1. Modeling results prove that the gas accumulation rule under cap layer and gas fraction on migration path. 2. Natural gas migration as free phase is difficult in dense rock. 3. Natural gases accumulated easily in good physical properties reservoirs where are under the plugging layer. Under the condition of that permeability of rock is more than 1 * 10~(-3)μm~(-1), the more better the physical properties and the more bigger pore of rock, the more easier the gas accumulation in there. On the contrary, natural gas canonly migrate further to accumulate in good physical properties of rock. 4. Natural gas migrate up is different from that down. Under the same situation, the amount of gas migration up is lager than that of gas migration down and the distance of migration up is 3 times as that of migration down. 5. After gas leaks from dense confining layer, the ability of its dynamic plug-back decreased apparently. Gas lost from these arils easily. These confining layer can confine again only after geology condition changes. 6. Water-wetted and capillary-blocking rocks can't block water but gases generally. The result is that water can migrate continuously through blocking rocks but the gases stay under the blocking rocks then form in there. The experiments have proved the formation model of deep basin gas.
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Based on the study of sequence stratigraphy, modern sedimentary, basin analysis, and petroleum system in Gubei depression, this paper builds high resolution sequence stratigraphic structure, sedimentary system, sandbody distribution, the effect of tectonic in sequence and sedimentary system evolution and model of tectonic-lithofacies. The pool formation mechanism of subtle trap is developed. There are some conclusions and views as follows. 1.With the synthetic sequence analysis of drilling, seismic, and well log, the highly resolution sequence structure is build in Gubei depression. They are divided two secondary sequences and seven three-order sequences in Shahejie formation. They are include 4 kinds of system traces and 7 kinds of sedimentary systems which are alluvial fan, under water fan, alluvial fan and fan-delta, fan-delta, lacustrine-fan, fluvial-delta-turbidite, lakeshore beach and bar, and deep lake system. Sandbody distribution is show base on third order sequence. 2.Based on a lot of experiment and well log, it is point out that there are many types of pore in reservoir with the styles of corrosion pore, weak cementing, matrix cementing, impure filling, and 7 kinds of diagenetic facies. These reservoirs are evaluated by lateral and profile characteristics of diagenetic facies and reservoir properties. 3.The effect of simultaneous faulting on sediment process is analyzed from abrupt slope, gentle slope, and hollow zone. The 4 kinds of tectonic lithofacies models are developed in several periods in Gubei depression; the regional distribution of subtle trap is predicted by hydro accumulation characteristics of different tectonic lithofacies. 4.There are 4 types of compacting process, which are normal compaction, abnormal high pressure, abnormal low pressure and complex abnormal pressure. The domain type is normal compaction that locates any area of depression, but normal high pressure is located only deep hollow zone (depth more than 3000m), abnormal low pressures are located gentle slope and faulted abrupt slope (depth between 1200~2500m). 5.Two types dynamic systems of pool formation (enclosed and partly enclosed system) are recognized. They are composed by which source rocks are from Es3 and Es4, cap rocks are deep lacustrine shale of Esl and Es3, and sandstone reservoirs are 7 kinds of sedimentary system in Es3 and Es4. According to theory of petroleum system, two petroleum systems are divided in Es3 and Es4 of Gubei depression, which are high or normal pressure self-source system and normal or low pressure external-source system. 6.There are 3 kinds of combination model of pool formation, the first is litholgical pool of inner depression (high or normal pressure self-source type), the second is fault block or fault nose pool in marginal of depression (normal type), the third is fault block-lithological pool of central low lifted block (high or normal pressure type). The lithological pool is located central of depression, other pool are located gentle or abrupt slope that are controlled by lithological, faulting, unconfirmed. 7.This paper raise a new technique and process of exploration subtle trap which include geological modeling, coring description and logging recognition, and well log constrained inversion. These are composed to method and theory of predicting subtle trap. Application these methods and techniques, 6 hydro objects are predicted in three zone of depression.
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The Grove Mountains, including 64 nunataks, is situated on an area about 3200km2 in the inland ice cap of east Antarctica in Princess Elizabeth land (72o20'-73°101S, 73°50'-75o40'E), between Zhongshan station and Dome A, about 450km away from Zhongshan station (69°22'S, 76°22'E). Many workers thought there was no pedogenesis in the areas because of the less precipitation and extreme lower temperature. However, during the austral summer in 1999-2000, the Chinaer 16 Antarctic expedition teams entered the inland East Antarctica and found three soil spots in the Southern Mount Harding, Grove Mountains, East Antarctica. It is the first case that soils are discovered in the inland in East Antarctica. Interestingly, the soils in this area show clay fraction migration, which is different from other cold desert soils. In addition, several moraine banks are discovered around the Mount Harding. The soil properties are discussed as below. Desert pavement commonly occurs on the three soil site surfaces, which is composed of pebbles and fragments formed slowly in typical desert zone. Many pebbles are subround and variegated. These pebbles are formed by abrasion caused by not only wind and wind selective transportation, but also salt weathering and thaw-freezing action on rocks. The wind blows the boulders and bedrocks with snow grains and small sands. This results in rock disintegration, paved on the soil surface, forming desert pavement, which protects the underground soil from wind-blow. The desert pavement is the typical feature in ice free zone in Antarctica. There developed desert varnish and ventifacts in this area. Rubification is a dominant process in cold desert Antarctic soils. In cold desert soils, rubification results in relatively high concentrations of Fed in soil profile. Stained depth increases progressively with time. The content of Fed is increasing up to surface in each profile. The reddish thin film is observed around the margin of mafic minerals such as biotite, hornblende, and magnetite in parent materials with the microscope analyzing on some soil profiles. So the Fed originates from the weathering of mafic minerals in soils. Accumulations of water-soluble salts, either as discrete horizons or dispersed within the soil, occur in the soil profiles, and the salt encrustations accumulate just beneath surface stones in this area. The results of X-ray diffraction analyses show that the crystalline salts consist of pentahydrite (MgSO4-5H2O), hexahydrite (MgSO4-6H2O), hurlbutite (CaBe2(PO4)2), bloedite (Na2Mg(S04)2-4H2O), et al., being mainly sulfate. The dominant cations in 1:5 soil-water extracts are Mg2+ and Na+, as well as Ca2+ and K+, while the dominant anion is SO42-, then NO3-, Cl- and HCO3-. There are white and yellowish sponge materials covered the stone underside surface, of which the main compounds are quartz (SiO2, 40.75%), rozenite (FeSOKkO, 37.39%), guyanaite (Cr2O3-1.5H2O, 9.30%), and starkeyite (MgSO4-4H2O, 12.56%). 4) The distribution of the clay fraction is related to the maximum content of moisture and salts. Clay fraction migration occurs in the soils, which is different from that of other cold desert soils. X-ray diffraction analyses show that the main clay minerals are illite, smectite, then illite-smectite, little kaolinite and veirniculite. Mica was changed to illite, even to vermiculite by hydration. Illite formed in the initial stage of weathering. The appearance of smectite suggests that it enriched in magnesium, but no strong eluviation, which belongs to cold and arid acid environment. 5) Three soil sites have different moisture. The effect moisture is in the form of little ice in site 1. There is no ice in site 2, and ice-cement horizon is 12 cm below the soil surface in site 3. Salt horizon is 5-10 cm up to the surface in Site 1 and Site 2, while about 26cm in site 3. The differentiation of the active layer and the permafrost are not distinct because of arid climate. The depth of active layer is about 10 cm in this area. Soils and Environment: On the basis of the characteristics of surface rocks, soil colors, horizon differentiation, salt in soils and soil depth, the soils age of the Grove Mountains is 0.5-3.5Ma. No remnants of glaciations are found on the soil sites of Mount Harding, which suggests that the Antarctic glaciations have not reached the soil sites since at least 0.5Ma, and the ice cap was not much higher than present, even during the Last Glacial Maximum. The average altitude of the contact line of level of blue ice and outcrop is 2050m, and the altitude of soil area is 2160m. The relative height deviation is about 110m, so the soils have developed and preserved until today. The parental material of the soils originated from alluvial sedimentary of baserocks nearby. Sporepollen were extracted from the soils, arbor pollen grains are dominant by Pinus and Betula, as well as a small amount Quercus, Juglans, Tilia and Artemisia etc. Judging from the shape and colour, the sporepollen group is likely attributed to Neogene or Pliocene in age. This indicates that there had been a warm period during the Neogene in the Grove Mountains, East Antarctica.
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The research area of this paper covers the maximum exploration projects of CNPC, including Blocks 1/2/4 and Block 6 of the Muglad basin and the Melut basin in Bocks 3/7 in Sudan. Based on the study of the evolution history of the Central African Shear Zone (CASZ), structural styles and filling characteristics of the rift basins, it is put forward that the rift basins in Sudan are typical passive rift basins undergoing the strike-slip, extension, compression and inversion since the Cretaceous. The three-stage rift basins overlapped obliquely. The extension and rifting during the Early Cretaceous is 50-70% of the total extension. The features of the passive rift basins decided that there is a single sedimentary cycle and one set of active source rocks within the middle. Influenced by the three-stage rifting and low thermal gradient, hydrocarbon generation and charging took place very late, and the oil pool formation mechanism is very unique from the Lower Cretaceous rift sequences to the Paleogene. The reservoir-seal assemblages are very complicated in time and space. The sealing capacity of cap rocks was controlled by the CASZ. In general the oils become heavier towards the CASZ and lighter far away. The oil biodegradation is the reason causing the high total acid number. The determination of effective reservoir depth ensures that all discovered fields up to now are high-production fields. The propagation and growth of boundary faults in the rift basins can be divided into a simple fault propagation pattern and a fault growth-linkage pattern. It is firstly found that the linkage of boundary fault segments controls the formation of petroleum systems. Three methods have been established to outline petroleum systems. And a new classification scheme of rift-type petroleum system has been put forward: pre-rift, syn-rift (including passive and active) and post-rift petroleum systems. This scheme will be very important for the further exploration of rift basins. This paper firstly established the formation models of oil pools for the passive rift basins in Sudan: the coupling of accommodation zones and main plays for the formation of giant fields. The overlapping of late rifting broke the anticlines to be several fault-blocks. This process determined that anti-fault blocks are the main traptypes in the cretaceous sequences and anticlines in the Paleogene. This can explain why the traptypes are different between the Muglad and Mefut basins, and will provide theoretic guidance for the exploration strategy. The established formation mechanism and models in this paper have had great potential guidance and promotion for the exploration in Sudan, and resulted in significant economic and social benefit. A giant field of 500 million tons oil in place was found 2003. The cost in Blocks 3/7 is only 0.25
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The main research area of this thesis is Jiyang Depression in the Bohaiwan Basin and its southern margin. The object formation is Ordovician carbonate. The research is based on the outcrop observation and measurement of Ordovician carbonate and the drilling data of the oilfield. The internal reservoir characteristics of carbonate buried hill and its distribution were studied by comprehensive methods of sedimentology, reservoir geology and structural geology and technics of cathodoluminescence(CL)3electron microprobe,casting and C O isotope analysis etc. The influence depth of paleokarst facies formed during the Paleozoic is discriminated as 36-84m. The sollution porosity is well developed in paleokarst facies of Ordovician carbonate and is an important type of internal reservoir of buried hill. It may be infered that the fractures may be formed mainly during the Mesozoic and Cenozoic, they were not developed during the early Paleozoic when only micro-fractures might be created. The carbon and oxigen isotope analysis shows that the calcite cements in the fractures of Ordovician carbonate and secondary solution pores were related with meteoric water and three stages of fractures were divided. The reservoir space of Ordovician carbonate are mainly secondary porosity, cavern and fracture. The development of structural fracture was controlled by the lithology and tectonic background. More fractures exist in dolomite than that in limestone. There are also more fractures near the fault and the axis of fold. The development of porous reservoir is mainly controlled by the lithology and diagenesis, especially dolomitization and dissolution. It also results in the heterogeneity vertically. So the lithology is the basic factor for the forming of internal reservoir of buried hill and the tectogenesis and diagenesis are key factors to improve it. The porosity in carbonate might experienced solution-cementation-resolution or recementation. The porosity evolution history was a kind of historical dynamic equilibrium. The internal reservoir of Ordovician carbonate is the comprehensive result of constructive and/or destructive diagenesis. The worm's eye maps of the early Paleozoic and middle-upper Proterozoic were plotted. It was inferred that the paleostress field evoluted from NNW to NW during the Mesozoic and Cenozoic. Three types of buried hills can be divided: C-P/Pzi, Mz/ Pzi and E/ Pzi. The unconformity of the buried hill of E/ Pzi type, comparatively, was formed and reconstructed latestly, t he p orous r eservoir c ould b e w ell p reseved. T his c ondition w as v ery favorable t o t he migration and accumulation of oil and gas and could form upstanding association of source-reservoir-cap rocks. The buried hills of Mz/ Pzi and C-P/Pz] type were took second place.
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In order to realize fast development of the national economy in a healthy way and coordinate progress with whole society, the country has implemented the strategy of development of the western region. An important action of finishing this strategic task is to accelerate the highway construction in the western region, join the western region and places along the coast, the river, the border with goods and materials, technology, and personnel interchanges, and then drive development of the local economy.The western region was influenced by the Himalaya Tectonization in Cenozoic, and the crust rose and became the plateau. In the course of rising, rivers cut down sharply to form a lot of high mountains and gorges.Because of topography and geomorphology, bridges in the traffic construction in the alpine gorge area are needed. Rivers have characteristics of large flow, fast velocity and high and steep river valley, so building a pier in the river is not only very difficult, but also making the cost increase. At the same time, the impact that the pier is corroded and the bridge base that is drawn to be empty by flow are apt to cause destruction of the pier. For those reasons, suspending bridge and cable-stay bridge are usually adopted with the single and large span. For the large span bridge, the pier foundation could receive ten thousand and more vertical strength, bending moment and near kiloton horizontal thrust.Because bank slope in the alpine gorge district is cut deeply and unsettled big, natural stability is worse under endogenic and exogenic force. When bank slope bears heavy vertical strength, bending moment and horizontal thrust facing the river, it will inevitably make the balance state of rock and soil mass change, bridge bank slope deform, and even destroyed. So the key problem at the time of the large span's bridge construction in the alpine gorge area is how to make it stable.So based on the spot investigation, the Engineering Geology Analysis Method is very important to grasp the bank slope stability. It can provide the bank slope stability macroscopic ally and qualitatively, and reference to the indoor calculation. The Engineering Geology Analysis Method is that by way of analyzing and investigating terms of bank slope instability, stability development trend, the ancient rock slide and devolution in the site, stability comprehensive evaluation primarily, current and future stability of bank slope is gotten, realizing the intention to serving the concrete engineering.After the Engineering Geology Analysis Method is applied to project instances of BeiPan River Bridge and BaLin River Bridge, results are accord with bank slope actual conditions, which proves sites are suited to building bridges from site stability.we often meet bank slope stability issues in the traffic construction in the alpine gorge areao Before the evaluation of the bank slope stability, the engineering geological condition is investigated first. After that, the next exploration target and geology measures are decided. So, the Engineering Geology Analysis Method that the investigation of the engineering geological condition is the main content is quite important in practice. The other evaluations of the bank slope stability are based on it. Because foundation receives very heavy load, for the big span's bridge in the alpine gorge area, a long pile of the large diameter (D^0.8m) is usually selected. In order to reflect rock mass's deformation properties under rock-socketed pile function, the author has used the FLAG30 software for rock and soil mass and done many numerical simulations. By them, the author launches the further investigation on deformation properties of bank slope under different slope angle, pile length, diameter, elastic modulus, load, bank slope's structure, etc. Some conclusion meaningful to the design and produce are obtained.