准噶尔盆地西缘车排子地区隐蔽油气藏识别与勘探目标研究

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.

基于弹性参数分析的碳酸盐岩储层预测方法研究

Prediction of Carbonate Reservoir Based on the Elastic Parameter Analysis Zhang Guangzhi (Solid Geophysics) Directed by Professor Liu Hong Abstract With the exploration and development of Puguang Oilfield, oil-gas exploration of carbonate rock in China has shown good prospects. Research on earthquake prediction methods for carbonate reservoir becomes the key of oil and gas exploration. Starting with analysis of geological characteristics of carbonate rock, prestack AVO inversion method, prestack elastic impedance inversion and parameter calculation method and seismic attribute extraction and optimization method were studied based on the analysis of rock physics in this work. First, variation characteristic and law of carbonate rock reservoir parameters were studied based on experimental data of rock physics, log data, analysis assay data, mud logging data and seismic data, so as to lay a foundation for the further reservoir identification and description. Then, the structure, type and propagation law of seismic wave field were analyzed through seismic forward modeling of the reservoir, and contact between information from log and geology data with elastic parameters, such as compressional wave and shear wave velocity and density were established, so as to provide a standard for reservoir identification and hydrocarbon detection using seismic reflection characteristics of the research area. Starting with the general concept of inverse problem, through analysis of Zoeppritz equation, three kinds of pre-stack inversion methods were derived and analyzed in detail, the AVO 3-parameter inversion based on Bayesian theory, the prestack AVO waveform inversion method and the simultaneous inversion method, based on the statistical hypothesis of inversion parameters and observation data and the Gauss distribution assumption of noise. The three methods were validated by model data and real data. Then, the elastic wave impedance inversion method of carbonate reservoir was investigated and the method of elastic parameter extraction from elastic impedance data was put forward. Based on the analysis of conventional methods of seismic attribute extraction and optimization, the time-frequency attributes and the wavelet attributes with time and amplitude feature were presented, and the prestack seismic attribute calculation method which can characterize the reservoir rock and fluid characteristic was presented. And the optimization of seismic attribute using the nonlinear KPCA method was also put forward. A series of seismic prediction technologies for carbonate reservoir were presented based on analysis of rock physics and seismic forward simulation technology. Practical application of these technologies was implemented in A oil field of Southern China and good effect has been achieved. Key words: carbonate rock; reservoir prediction; rock physics, prestack seismic inversion; seismic attribute

青藏高原及邻区面波频散反演--岩石圈-软流层体系结构研究

The Qinghai-Tibet Plateau lies in the place of the continent-continent collision between Indian and Eurasian plates. Because of their interaction the shallow and deep structures are very complicated. The force system forming the tectonic patterns and driving tectonic movements is effected together by the deep part of the lithosphere and the asthenosphere. It is important to study the 3-D velocity structures, the spheres and layers structures, material properties and states of the lithosphere and the asthenosphere for getting knowledge of their formation and evolution, dynamic process, layers coupling and exchange of material and energy. Based on the Rayleigh wave dispersion theory, we study the 3-D velocity structures, the depths of interfaces and thicknesses of different layers, including the crust, the lithosphere and the asthenosphere, the lithosphere-asthenosphere system in the Qinghai-Tibet Plateau and its adjacent areas. The following tasks include: (1)The digital seismic records of 221 seismic events have been collected, whose magnitudes are larger than 5.0 over the Qinghai-Tibet Plateau and its adjacent areas. These records come from 31 digital seismic stations of GSN , CDSN、NCDSN and part of Indian stations. After making instrument response calibration and filtering, group velocities of fundamental mode of Rayleigh waves are measured using the frequency-time analysis (FTAN) to get the observed dispersions. Furthermore, we strike cluster average for those similar ray paths. Finally, 819 dispersion curves (8-150s) are ready for dispersion inversion. (2)From these dispersion curves, pure dispersion data in 2°×2° cells of the areas (18°N-42°N, 70°E-106°E) are calculated by using function expansion method, proposed by Yanovskaya. The average initial model has been constructed by taking account of global AK135 model along with geodetic, geological, geophysical, receiving function and wide-angle reflection data. Then, initial S-wave velocity structures of the crust and upper mantle in the research areas have been obtained by using linear inversion (SVD) method. (3)Taking the results of the linear inversion as the initial model, we simultaneously invert the S wave velocities and thicknesses by using non-linear inversion (improved Simulated Annealing algorithm). Moreover, during the temperature dropping the variable-scale models are used. Comparing with the linear results, the spheres and layers by the non-linear inversion can be recognized better from the velocity value and offset. (4)The Moho discontinuity and top interface of the asthenosphere are recognized from the velocity value and offset of the layers. The thicknesses of the crust, lithosphere and asthenosphere are gained. These thicknesses are helpful to studying the structural differentia between the Qinghai-Tibet Plateau and its adjacent areas and among geologic units of the plateau. The results of the inversion will provide deep geophysical evidences for studying deep dynamical mechanism and exploring metal mineral resource and oil and gas resources. The following conclusions are reached by the distributions of the S wave velocities and thicknesses of the crust, lithosphere and asthenosphere, combining with previous researches. (1)The crust is very thick in the Qinghai-Tibet Plateau, varying from 60 km to 80 km. The lithospheric thickness in the Qinghai-Tibet Plateau is thinner (130-160 km) than its adjacent areas. Its asthenosphere is relatively thicker, varies from 150 km to 230 km, and the thickest area lies in the western Qiangtang. India located in south of Main Boundary thrust has a thinner crust (32-38 km), a thicker lithosphere of about 190 km and a rather thin asthenosphere of only 60 km. Sichuan and Tarim basins have the crust thickness less than 50km. Their lithospheres are thicker than the Qinghai-Tibet Plateau, and their asthenospheres are thinner. (2)The S-wave velocity variation pattern in the lithosphere-asthenosphere system has band-belted distribution along east-westward. These variations correlate with geology structures sketched by sutures and major faults. These sutures include Main Boundary thrust (MBT), Yarlung-Zangbo River suture (YZS), Bangong Lake-Nujiang suture (BNS), Jinshajiang suture (JSJS), Kunlun edge suture (KL). In the velocity maps of the upper and middle crust, these sutures can be sketched. In velocity maps of 250-300 km depth, MBT, BNS and JSJS can be sketched. In maps of the crustal thickness, the lithospheric thickness and the asthenospheric thickness, these sutures can be still sketched. In particular, MBT can be obviously resolved in these velocity maps and thickness maps. (3)Since the collision between India and Eurasian plate, the “loss” of surface material arising from crustal shortening is caused not only by crustal thickening but also by lateral extrusion material. The source of lateral extrusion lies in the Qiangtang block. These materials extrude along the JSJS and BNS with both rotation and dispersion in Daguaiwan. Finally, it extends toward southeast direction. (4)There is the crust-mantle transition zone of no distinct velocity jump in the lithosphere beneath the Qiangtang Terrane. It has thinner lithosphere and developed thicker asthenosphere. It implies that the crust-mantle transition zone of partial melting is connected with the developed asthenosphere. The underplating of asthenosphere may thin the lithosphere. This buoyancy might be the main mechanism and deep dynamics of the uplift of the Qinghai-Tibet hinterland. At the same time, the transport of hot material with low velocity intrudes into the upper mantle and the lower crust along cracks and faults forming the crust-mantle transition zone.

天然气藏地震识别技术研究

The Research of Seismic Recognition Techniques for Gas Reservoir Shang Yong_sheng(Geophysics) Directed by Yang Chang-chun Abstract Gas reservior is one of the most important nature resources. Someone forecast that the output will exceed crude oil in 2015 and become the largest energy source. Recently,more and more gas reservior are discovered as the oil field and gas filed exploration go deep into development. Although the gas proved reserves rise greatly the explorative degree of natural gas resource in our country is still very low. The potential of gas exploration is very great and our task is so hard. How to recognise and discover new gas reservoir is the first task based on the great gas reservior resources foreground. the gas reservior in different oil and gas field have its special gas generation, reservoiring, physical property conditions. However,it may have the same geophysical characters. So,it is very important to analyse, research, summarizing the geophysical characters of the gas reservior and make use of the characters to identify the gas layer effectively. This paper start with modeling,and it discuss the geophysical characters of the gas reservior response. It analyse the seismical wave characters of the gas reservoir. Furthermore, it summarize the method of using the seismica profile to identify the gas reservior directly. The paper discuss the research of extracting diffraction wave for mass diffraction wave grow at the edge of the gas reservoir at the seismic section. Making use of the technique of extracting diffraction wave to identify the gas reservior is the first experiment of the gas reservoir prediction technique. The avo technology is a new geophysical method. From the pre-stack analysis, this paper discuss the technique of using the rich information to identify the gas reservoir. Based on the case study of the Qidam basin and the Hailaer basin it discuss the method of predicating gas reservoir using pre-stack information. It include pre-stack amplitude preserve process, AVO modeling, fluid replacement technique, AVO analysis and interpretation technique. The paper summarize a gas reservoir prediction procedure focusing on the pre-stack information. The seismic wave will cause great attenuation when it pass through the gas layer and the high frequency component loss. This paper discuss the technique of extracting seismic attributes to represent the attenuation degree of seismica wave. Based on the attenuation attributes,it does the research of the gas reservor identification and prediction. At last,the paper discuss the method of calculating the azimuthal anisotropy to predict the fracture reservoir. Keyword: gas reservoir, diffraction wave, AVO, attenuation attribute,fracture prediction

油气勘探中的弱磁异常提取与区域场分析

Petroleum and natural gas is an important strategic resources. The short of the reserves will block the development of economy and threaten the safety of nation, along with the main oil fields of our country coming to the height of power and splendor of the exploitation and exploration. Therefore, it makes a great sense to inaugurate new explorative field and increase the reserves of petroleum and natural gas. Magnetic exploration is a main method of geophysics exploration. the developing observation apparatus and the perfect processing method provide wide space for magnetic exploration in these years. The method of magnetic bright spot is an application of magnetic exploration. The vertical migration of the hydrocarbon changes physical and chemical environment above the hydrocarbon reservoir, the new environment make tervalent iron translate into bivalent iron, that produce small scale magnetic anomaly, that is magnetic bright spot. The method of magnetic bright spot explores oil and gas field by the relation between the hydrocarbon and magnetic anomaly. This paper systemically research to pick-up and identify magnetic bright spot combining an oil field item, then point out advantaged area. In order to test the result, the author use the seismic information to superpose the magnetic bright spot, that prove the magnetic bright spot is reliable. then, the author complete a software to pick and identify the magnetic bright spot. The magnetic basement is very important to research forming and evolvement of the basin, especially, it is a crucial parameter of exploring residual basin in the research on pre-Cenozoic residual. This paper put forward a new method to inverse the interface of the magnetic layer on the basis of previous work, that is the method of separation of magnetic field step by step. The theory of this method is to translate the result of magnetic layer fluctuation to the result of magnetization density change, and the magnetic layer is flat, the paper choose thickness of magnetic layer as unit thickness, and define magnetic layer as a unit-thickness layer in order to convenient calculation, at the same time, define the variational magnetization density as equivalent magnetic density. Then we translate the relation between magnetic field and layer fluctuation to the relation between magnetic field and equivalent magnetic density, then, we can obtain the layer fluctuation through calculating equivalent magnetic density. Contrast to conventional parker method, model experimentation and example checkout prove this method is effective. The merit of this method is to avoid flat result in a strongly fluctuant area because of using a uniform average depth, the result of this method is closer to the fact, and this method is to inverse equivalent magnetic density, then translate equivalent magnetic density to layer fluctuation, this lays a foundation to inverse variational magnetic density in the landscape orientation and portrait.

基于随机介质理论的多尺度储层非均质性定量描述

Application of long-term exploration for oil and gas shows that the reservoir technology of prediction is one of the most valuable methods. Quantitative analysis of reservoir complexity is also a key technology of reservoir prediction. The current reservoir technologies of prediction are based on the linear assumption of various physical relationships. Therefore, these technologies cannot handle complex reservoirs with thin sands, high heterogeneities in lithological composition and strong varieties in petrophysical properties. Based on the above-mentioned complex reservoir, this paper conducts a series of researches. Both the comprehending and the quantitative analysis of reservoir heterogeneities have been implemented using statistical and non-linear theories of geophysics. At the beginning, the research of random media theories about reservoir heterogeneities was researched in this thesis. One-dimensional (1-D) and two-dimensional (2-D) random medium models were constructed. The autocorrelation lengths of random medium described the mean scale of heterogeneous anomaly in horizontal and deep directions, respectively. The characteristic of random medium models were analyzed. We also studied the corresponding relationship between the reservoir heterogeneities and autocorrelation lengths. Because heterogeneity of reservoir has fractal nature, we described heterogeneity of reservoir by fractal theory based on analyzing of the one-dimensional (1-D) and two-dimensional (2-D) random medium models. We simulated two-dimensional (2-D) random fluctuation medium in different parameters. From the simulated results, we can know that the main features of the two-dimensional (2-D) random medium mode. With autocorrelation lengths becoming larger, scales of heterogeneous geologic bodies in models became bigger. In addition, with the autocorrelation lengths becoming very larger, the layer characteristic of the models is very obvious. It would be difficult to identify sandstone such as gritstone, clay, dense sandstone and gas sandstone and so on in the reservoir with traditional impedance inversion. According to the obvious difference between different lithologic and petrophysical impedance, we studied multi-scale reservoir heterogeneities and developed new technologies. The distribution features of reservoir lithological and petrophysical heterogeneities along vertical and transverse directions were described quantitatively using multi-scale power spectrum and heterogeneity spectrum methods in this paper. Power spectrum (P spectrum) describes the manner of the vertical distribution of reservoir lithologic and petrophysical parameters and the large-scale and small-scale heterogeneities along vertical direction. Heterogeneity spectrum (H spectrum) describes the structure of the reservoir lithologic and petrophysical parameters mainly, that is to say, proportional composition of each lithological and petrophysical heterogeneities are calculated in this formation. The method is more reasonable to describe the degree of transverse multi-scale heterogeneities in reservoir lithological and petrophysical parameters. Using information of sonic logs in Sulige oil field, two spectral methods have been applied to the oil field, and good analytic results have been obtained. In order to contrast the former researches, the last part is the multi-scale character analysis of reservoir based on the transmission character of wave using the wavelet transform. We discussed the method applied to demarcate sequence stratigraphy and also analyzed the reservoir interlayer heterogeneity.

埕北断阶带油气运聚动力学研究

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

松辽盆地古龙地区葡萄花油层组沉积成岩相研究

The sediment and diagenesis process of reservoir are the key controlling factors for the formation and distribution of hydrocarbon reservoir. For quite a long time, most of the research on sediment-diagenesis facise is mainly focusing on qualitative analysis. With the further development on exploration of oil field, the qualitative analysis alone can’t meet the requirements of complicated requirements of oil and gas exploreation, so the quantitative analysis of sediment-diagenesis facise and related facies modling have become more and more important. On the basis of the research result from stratum and sediment on GuLong Area Putaohua Oil Layer Group, from the basic principles of sedimentology, and with the support from the research result from field core and mining research results, the thesis mainly makes the research on the sediment types, the space framework of sands and the evolution rules of diagenesis while mainly sticking to the research on sediment systement analysis and diagenetic deformation, and make further quantitative classification on sediment-diageneses facies qualitatively, discussed the new way to divide the sediment-diagenesis facies, and offer new basis for reservoir exploration by the research. Through using statistics theory including factor analysis, cluster analysis and discriminant analysis, the thesis devided sediment-diagenesis facies quantitatively. This research method is innovative on studying sediment-diagenesis facies. Firstly, the factor analysis could study the main mechanism of those correlative variables in geologic body, and then could draw a conclusion on the control factors of fluid and capability of reservoir in the layer of studying area. Secondly, with the selected main parameter for the cluster analysis, the classification of diagenesis is mainly based on the data analysis, thus the subjective judgement from the investigator could be eliminated, besides the results could be more quantitative, which is helpful to the correlative statistical analysis, so one could get further study on the quantitative relations of each sediment-diagenesis facies type. Finally, with the reliablities of discriminant analysis cluster results, and the adoption of discriminant probability to formulate the chart, the thesis could reflect chorisogram of sediment-diagenesis facies for planar analysis, which leads to a more dependable analytic results.According to the research, with the multi-statistics analysis methods combinations, we could get quantitative analysis on sediment-diagenesis facies of reservoir, and the final result could be more reliable and also have better operability.

油气输导体系研究及应用─以准噶尔盆地东部白家海凸起侏罗系为例

Baijiahai uplift is an important hydrocarbon accumulation belt in eastern Jungger Basin, on which Cainan oilfield and lithologic hydrocarbon reservoir named Cai 43 have been discovered and both of them share the same target formation of Jurassic. However, in the subsequent exploration at this region, several wells that designed for lithologic traps of Jurassic were eventually failed, and that indicates the controlling factors of lithologic reservoir distribution are far more complicated than our previous expectation. This dissertation set the strata of the Jurassic in well Cai 43 region as the target, and based on the integrated analysis of structure evolution、fault sealing ability、simulations of sedimentary microfacies and reservoir beds、distribution analysis of high porosity-high permeability carrier beds、drive forces of hydrocarbons、preferential conduit system and conduit model as well as critical values of the reservoir physical properties for hydrocarbon charging, a special method that different from the conventional way to predict favorable lithologic traps was established. And with this method the controlling factors of the hydrocarbon reservoirs formation are figured out, and further more, the favorable exploration targets are point out. At Baijiahai uplift, fault plays as a crucial factor in the process of the hydrocarbon reservoir formation. In this study, it is found out that the availability of a fault that work as the seal for oil and gas are different. The critical value of the lateral mudstone smear factor (Kssf), which is used to measure the lateral sealing ability of fault, for oil is 3.9 while that for gas is 2.1; and the critical value of vertical sealing factor (F), which similarly a measurement for the vertical sealing ability of fault, for oil is 7.3 while that for gas is 5.1. Dongdaohaizi fault belt that possessed well lateral sealing ability since later Cretaceous have bad vertical sealing ability in later Cretaceous, however, it turns to be well now. Based on the comparison of the physical properties that respectively obtained from electronic log calculating、conventional laboratory rock analysis and the additive-pressure bearing laboratory rock analysis, we established the functions through which the porosity and permeability obtained though conventional method can be converted to the values of the subsurface conditions. With this method, the porosity and permeability of the Jurassic strata at the time of previous Tertiary and that in nowadays are reconstructed respectively, and then the characteristics of the distribution of high porosity-high permeability carrier beds in the evolution processes are determined. With the result of these works, it is found that both well Cai 43 region and Cainan oilfield are located on the preferential conduit direction of hydrocarbon migration. This conclusion is consistent with the result of the fluid potential analysis, in which fluid potential of nowadays and that of later Cretaceous are considered. At the same times, experiment of hydrocarbon injection into the addictive-pressure bearing rock is designed and conducted, from which it is found that, for mid-permeability cores of Jurassic, 0.03MPa is the threshold values for the hydrocarbon charging. And here, the conception of lateral pressure gradient is proposed to describe the lateral driving force for hydrocarbon migration. With this conception, it is found that hydrocarbons largely distributed in the areas where lateral pressure gradient is greater than 0. 03MPa/100m. Analysis of critical physical properties indicated that the value of the critical porosity and critical permeability varied with burial depth, and it is the throat radius of a certain reservoir bed that works as a key factor in controlling hydrocarbon content. Three parameters are proposed to describe the critical physical properties in this dissertation, which composite of effective oil-bearing porosity、effective oil-bearing permeability and preferential flow coefficient. And found that critical physical properties, at least to some extent, control the hydrocarbon distribution of Jurassic in Baijiahai uplift. Synthesize the content discussed above, this dissertation analyzed the key factors i.e., critical physical properties、driving force、conduit system and fluid potential, which controlled the formation of the lithologic reservoir in Baijiahai uplift. In all of which conduit system and fluid potential determined the direction of hydrocarbon migration, and substantially they are critical physical properties of reservoir bed and the lateral pressure gradient that controlled the eventually hydrocarbon distribution. At the same times, sand bodies in the major target formation that are recognized by reservoir bed simulation are appraised, then predict favorite direction of the next step exploration of lithologic reservoir.

西峰油田特低渗透油藏渗流机理及开发对策研究

Micro-pore-throat, micro-fracture and low permeability are the most obvious characters of Xifeng ultra-low permeability reservoir, and threshold pressure gradient and medium deformation during the period of oilfield developing results non-linear seepage feature of the formation liquid flowing in the porous medium underground. It is impossible to solve some problems in the ultra-low permeability reservoir development by current Darcy filtration theory and development techniques. In the view of the characters of ultra-low permeability and powerful-diagenesis and fracture up-growth, the paper quantitatively characterizes of through-going scope for reservoir parameters together with some materials such as similarity field outcrop, rock core, drilling, well logging and production dynamic, which provides geological base for further development adjustment. Based on the displacement experiment of different kinds of seepage fluid and oil-water two phases, this paper proves the relationship between threshold pressure gradient and formation permeability in experiment and theory, which is power function and its index is about -1. The variation rule and the mechanism of oil-water two phases threshold pressure gradient are studied. At the same time, based on the experiment of medium deformation, the variation rule of formation physical property parameters and the deformation mechanism are researched, and the influential factors on the medium deformation are analyzed systematically. With elastic unsteady filtration theory, nonlinear mathematical models of the steady and unsteady flow of single phase as well as horizontal well flow and oil-water two phases flow are deduced with the influence of nonlinear factors including threshold pressure gradient and media deformation. The influences of nonlinear factors upon well deliverability and reservoir pressure distribution as well as the saturation variation pattern of oil-water front are analyzed. By means of the researches such as reasonable well pattern, reasonable well array ration, artificial fracture length optimization advisable water flood timing and feasibility of advanced water flooding, it is necessary to find out effective techniques in order to improve development result of this kind of reservoir. This research result develops and improves on low-velocity nonlinear seepage theory, and offers ways to study similar kind of reservoir; it is meaningful to the development of the ultra-low permeability oil and gas reservoir.

柴达木盆地北缘西段油气运聚动力学研究

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

均衡重力异常计算与综合解释——以黄海地区为例

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

AVO分析与地震资料叠前储层预测技术

In this paper we base on the anisotropic theory and Zoeppritz function of the transmission theory and the law of amplitude versus offset simplify seismic reflection coefficient of different media, analyze the characteristic of the gas or oil saturated stratum or the VTI and HTI models. Discuss the P wave reflection relationship and the meanings of the different parameters. We use measured parameters of a reservoir to simulate the characteristic of the reservoir, study the different effects of stratum saturated with gas or oil and analyze the characteristic of the seismic response of different models which change with different incident angles and different azimuths. Using the field data of logs ,analyze the rock property parameters, build the relationship of logs and parameters by Gassmann theory or empirical function. Calculate the density and the shear modulus and bulk modulus, reconstruct the log curves, calculate shear wave logs and correlate the logs affected by mud and other environmental factors. Finally perform the relationship of the seismic data log of saturated stratum and enhance the ability and reliability in reservoir prediction. Our aim is by the prestack seismic processing to get high solution and amplitude preserved seismic data. Because in incident angle gathers or azimuthal gathers, the low signal to noise ratio and low different covers affect the result of the prestack reservoir prediction. We apply prestack noise erase, cell regularization process and relatively amplitude preservation in the high solution seismic process routine to preserve the characteristic of stratum response, and erase the effects of the noise. In this paper we finished prestack invertion in the BYT survey and fractured reservoir depiction in MB survey. By the invertion and multiple attributes crossplot. we can get the stratum profiles and oil indicator profiles which can predict the distribution of the reservoir and oil. In the MB survey, we get orientation and density of fractured reservoir by the azimuthal seismic amplitude and depict the potential oil and gas reservoir. Prestak invertion works better in distinguishing oil and reservoir.

北部湾盆地迈陈凹陷地震勘探方法研究

Maichen Depression lie between Leizhou Peninsula and Qiongzhou Strait. Oil and gas have been discovered in Weixinan Depression, Wushi Depression and Fushan Depression, which pertain to a same basin — North Sea Basin along with Maichen Depression.Jiangsu Oil started exploration at 2002. The first well began to drill at November, 2004 after gravity survey, electric method prospecting and 2D seismic exploration had been finished. Generating rock and hydrocarbon shows have been verified by the drilling. Low yield oil stream has been tested. And we started 3D seismic exploration at November, 2005. My thesis topic came from the actual needs of our exploration in the Maichen Depression. In the thesis, I give emphasis to analyse the own seismic geologic conditions of Maichen Depression. By real tests, we choosed the means to overcome or weaken the unfavorably impress owing to the own coditions in Maichen Depression. Finally, we obtained the usable seismic data. 1. Owing to the multiphase eruptive rock during the Quaternary Period, the near surface layers are very inhomogeneous. By simultaneous testing at same point with short refraction, uphole surveys of radial source and of surface source, the most appropriate method had been sorted out. Radial source uphole survey has been regarding the best practicable means in the complex area. Accurate surficial geology was very helpful to choosing of acquirement means and parameters. Basically the appropriate method of seismic acquirement has been built at Maichen area. 2. The seismic primary data has many, very strong and complex noise. By noise characteristic analysis in different domain, many means of denoising had been paralleled individual and joint application researched. As a result, the pre-stack multidomain joint denoise flow was the appropriate method. It can improve the seismic signal-to-noise ratio. 3. The problem of seismic static correction at Maichen Depression is very conspicuous. Many static correction methods had been tested individual and joint researched. The seismic data quality has been improved after choosing the appropriate combination of static correction flows. 4. Although the above-mentioned process are resultful, the seismic profile quality is just passable. Some reflector continuity and fault zone imagery are ambiguity. So it was the useful method to reduce the structural ambiguity during seismic interpretation that built-up geologic model in accord with real geologic character by areal structure study upon backbone seismic profiles. In the same way, traps have been assessed and drill targets have been selected.

消除采集脚印的处理方法研究

Seismic technique is in the leading position for discovering oil and gas trap and searching for reserves throughout the course of oil and gas exploration. It needs high quality of seismic processed data, not only required exact spatial position, but also the true information of amplitude and AVO attribute and velocity. Acquisition footprint has an impact on highly precision and best quality of imaging and analysis of AVO attribute and velocity. Acquisition footprint is a new conception of describing seismic noise in 3-D exploration. It is not easy to understand the acquisition footprint. This paper begins with forward modeling seismic data from the simple sound wave model, then processes it and discusses the cause for producing the acquisition footprint. It agreed that the recording geometry is the main cause which leads to the distribution asymmetry of coverage and offset and azimuth in different grid cells. It summarizes the characters and description methods and analysis acquisition footprint’s influence on data geology interpretation and the analysis of seismic attribute and velocity. The data reconstruct based on Fourier transform is the main method at present for non uniform data interpolation and extrapolate, but this method always is an inverse problem with bad condition. Tikhonov regularization strategy which includes a priori information on class of solution in search can reduce the computation difficulty duo to discrete kernel condition disadvantage and scarcity of the number of observations. The method is quiet statistical, which does not require the selection of regularization parameter; and hence it has appropriate inversion coefficient. The result of programming and tentat-ive calculation verifies the acquisition footprint can be removed through prestack data reconstruct. This paper applies migration to the processing method of removing the acquisition footprint. The fundamental principle and algorithms are surveyed, seismic traces are weighted according to the area which occupied by seismic trace in different source-receiver distances. Adopting grid method in stead of accounting the area of Voroni map can reduce difficulty of calculation the weight. The result of processing the model data and actual seismic demonstrate, incorporating a weighting scheme based on the relative area that is associated with each input trace with respect to its neighbors acts to minimize the artifacts caused by irregular acquisition geometry.