997 resultados para Geophysics.
Resumo:
On 70~(th) SEG Annual meeting, many author have announced their result on the wave equation prestack depth migration. The methods of the wave-field imaging base on wave equation becomes mature and the main direction of seismic imaging. The direction of imaging the complex media has been the main one of the projects that the national "85" and "95" reservoir geophysics key projects and "Knowledge innovation key project of Chinese Academy of Science" have been supported. Furthermore, we began the study for special oil field situation of our nation with the international research groups. Under the background, the author combined the thoughts of symplectic with wave equation pre-stack depth migration, and develops and efficient wave equation pre-stack depth migration method. The purpose of this work is to find out a way to imaging the complex geological goals of Chinese oilfields and form a procedure of seismic data processing. The paper gives the approximation of one way wave equation operator, and shows the numerical results. The comparisons have been made between split-step phase method, Kirchhoff and Ray+FD methods on the pulse response, simple model and Marmousi model. The results shows that the method in this paper has an higher accuracy. Four field data examples have also be given in this paper. The results of field data demonstrate that the method can be usable. The velocity estimation is an important part of the wave equation pre-stack depth migration. A parallel velocity estimation program has been written and tested on the Beowulf clusters. The program can establish a velocity profile automatically. An example on Marmousi model has shown in the third part of the paper to demonstrate the method. Another field data was also given in the paper. Beowulf cluster is the converge of the high performance computer architecture. Today, Beowulf Cluster is a good choice for institutes and small companies to finish their task. The paper gives some comparison results the computation of the wave equation pre-stack migration on Beowulf cluster, IBM-SP2 (24 nodes) in Daqing and Shuguang 3000, and the comparison of their prize. The results show that the Beowulf cluster is an efficient way to finish the large amount computation of the wave equation pre-stack depth migration, especially for 3D.
Resumo:
On 70~(th) SEG Annual meeting, many author have announced their result on the wave equation pre-stack depth migration. The methods of the wave-field imaging base on wave equation becomes mature and the main direction of seismic imaging. The direction of imaging the complex media has been the main one of the projects that the national "85" and "95" reservoir geophysics key projects and "Knowledge innovation key project of Chinese Academy of Science" have been supported. Furthermore, we began the study for special oil field situation of our nation with the international research groups. Under the background, the author combined the thoughts of symplectic with wave equation pre-stack depth migration, and develops and efficient wave equation pre-stack depth migration method. The purpose of this work is to find out a way to imaging the complex geological goals of Chinese oilfields and form a procedure of seismic data processing. The paper gives the approximation of one way wave equation operator, and shows the numerical results. The comparisons have been made between split-step phase method, Kirchhoff and Ray+FD methods on the pulse response, simple model and Marmousi model. The result shows that the method in this paper has an higher accuracy. Four field data examples have also be given in this paper. The results of field data demonstrate that the method can be usable. The velocity estimation is an important part of the wave equation pre-stack depth migration. A. parallel velocity estimation program has been written and tested on the Beowulf clusters. The program can establish a velocity profile automatically. An example on Marmousi model has shown in the third part of the paper to demonstrate the method. Another field data was also given in the paper. Beowulf cluster is the converge of the high performance computer architecture. Today, Beowulf Cluster is a good choice for institutes and small companies to finish their task. The paper gives some comparison results the computation of the wave equation pre-stack migration on Beowulf cluster, IBM-SP2 (24 nodes) in Daqing and Shuguang3000, and the comparison of their prize. The results show that the Beowulf cluster is an efficient way to finish the large amount computation of the wave equation pre-stack depth migration, especially for 3D.
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Impedance inversion is very important in seismic technology. It is based on seismic profile. Good inversion result is derived from high quality seismic profile, which is formed using high resolution imaging resolution. High-resolution process demands that signal/noise ratio is high. It is very important for seismic inversion to improve signal/noise ratio. the main idea is that the physical parameter (wave impedance), which describes the stratigraphy directly, is achieved from seismic data expressing structural style indirectly. The solution of impedance inversion technology, which is based on convolution model, is arbitrary. It is a good way to apply the priori information as the restricted condition in inversion. An updated impedance inversion technology is presented which overcome the flaw of traditional model and highlight the influence of structure. Considering impedance inversion restricted by sedimentary model, layer filling style and congruence relation, the impedance model is built. So the impedance inversion restricted by geological rule could be realized. there are some innovations in this dissertation: 1. The best migration aperture is achieved from the included angle of time surface of diffracted wave and reflected wave. Restricted by structural model, the dip of time surface of reflected wave and diffracted wave is given. 2. The conventional method of FXY forcasting noise is updated, and the signal/noise ratio is improved. 3. Considering the characteristic of probability distribution of seismic data and geological events fully, an object function is constructed using the theory of Bayes estimation as the criterion. The mathematics is used here to describe the content of practice theory. 4. Considering the influence of structure, the seismic profile is interpreted to build the model of structure. A series of structure model is built. So as the impedance model. The high frequency of inversion is controlled by the geological rule. 5. Conjugate gradient method is selected to improve resolving process for it fit the demands of geophysics, and the efficiency of algorithm is enhanced. As the geological information is used fully, the result of impedance inversion is reasonable and complex reservoir could be forecasted further perfectly.
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At present the main object of the exploration and development (E&D) of oil and gas is not the structural oil-gas pools but the subtle lithological oil-gas reservoir. Since the last 90's, the ratio of this kind of pools in newly-added oil reserves is becoming larger and larger, so is the ratio in the eastern oilfields. The third oil-gas resource evaluation indicates the main exploration object of Jiyang depression is the lithological oil-gas pools in future. However, lack of effective methods that are applied to search for this kind of pool makes E&D difficult and the cost high. In view of the urgent demand of E&D, in this paper we deeply study and analyze the theory and application in which the seismic attributes are used to predict and describe lithological oil-gas reservoirs. The great results are obtained by making full use of abundant physics and reservoir information as well as the remarkable lateral continuity involved in seismic data in combination with well logging, drilling-well and geology. ①Based on a great deal of research and different geological features of Shengli oilfield, the great progresses are made some theories and methods of seismic reservoir prediction and description. Three kinds of extrapolation near well seismic wavelet methods-inverse distance interpolation, phase interpolation and pseudo well reflectivity-are improved; particularly, in sparse well area the method of getting pseudo well reflectivity is given by the application of the wavelet theory. The formulae for seismic attributes and coherent volumes are derived theoretically, and the optimal method of seismic attributes and improved algorithms of picking up coherent data volumes are put forward. The method of making sequence analysis on seismic data is put forward and derived in which the wavelet transform is used to analyze not only qualitatively but also quantitatively seismic characteristics of reservoirs.② According to geologic model and seismic forward simulation, from macro to micro, the method of pre- and post-stack data synthetic analysis and application is put forward using seismic in close combination with geology; particularly, based on making full use of post-stack seismic data, "green food"-pre-stack seismic data is as possible as utilized. ③ In this paper, the formative law and distributing characteristic of lithologic oil-gas pools of the Tertiary in Jiyang depression, the knowledge of geological geophysics and the feasibility of all sorts of seismic methods, and the applied knowledge of seismic data and the geophysical mechanism of oil-gas reservoirs are studied. Therefore a series of perfect seismic technique and software are completed that fit to E&D of different categories of lithologic oil-gas reservoirs. ④ This achievement is different from other new seismic methods that are put forward in the recent years, that is multi-wave multi-component seismic, cross hole seismic, vertical seismic, and time-lapse seismic etc. that need the reacquisition of seismic data to predict and describe the oil-gas reservoir. The method in this paper is based on the conventional 2D/3D seismic data, so the cost falls sharply. ⑤ In recent years this technique that predict and describe lithologic oil-gas reservoirs by seismic information has been applied in E&D of lithologic oil-gas reservoirs on glutenite fans in abrupt slop and turbidite fans in front of abrup slop, slump turbidite fans in front of delta, turbidite fans with channel in low slope and channel sanbody, and a encouraging geologic result has been gained. This achievement indicates that the application of seismic information is one of the most effective ways in solving the present problem of E&D. This technique is significant in the application and popularization, and positive on increasing reserves and raising production as well as stable development in Shengli oilfield. And it will be directive to E&D of some similar reservoirs
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Since 1970s, igneous reservoirs such as Shang741, Bin674 and Luol51 have been found in Jiyang depression, which are enrichment and heavy-producing. Showing good prospect of exploration and development, igneous reservoirs have been the main part of increasing reserves and production in Shengli oilfield. As fracture igneous reservoir being an extraordinary complex concealed reservoir and showing heavy heterogeneity in spatial distribution, the study of recognition, prediction, formation mechanism and the law of distribution of fracture is essential to develop the reservoir. Guided by multiple discipline theory such as sedimentology, geophysics, mineralogy, petroleum geology, structural geology and reservoir engineering, a set of theories and methods of recognition and prediction of fractured igneous rock reservoir are formed in this paper. Rock data, three-dimensional seismic data, log data, borehole log data, testing data and production data are combined in these methods by the means of computer. Based on the research of igneous rock petrography and reservoir formation mechanism, emphasized on the assessment and forecast of igneous rock reservoir, aimed at establishing a nonhomogeneity quantification model of fractured igneous rock reservoir, the creativity on the fracture recognition, prediction and formation mechanism are achieved. The research result is applied to Jiyang depression, suggestion of exploration and development for fractured igneous rock reservoir is supplied and some great achievement and favourable economic effect are achieved. The main achievements are gained as follows: 1. The main facies models of igneous rock reservoir in JiYang depression are summarized. Based on data and techniques of seism, well log and logging,started from the research of single well rock facies, proceeded by seismic and log facies research, from point to line and line to face, the regional igneous facies models are established. And hypabyssal intrusion allgovite facies model, explosion volcaniclastic rock facies model and overfall basaltic rocks facies model are the main facies models of igneous rock reservoir in JiYang depression. 2. Four nonhomogenous reservoir models of igneous reservoirs are established, which is the base of fracture prediction and recognition. According to characteristics of igneous petrology and spatial types of reservoir, igneous reservoirs of Jiyang depression are divided into four categories: fractured irruptive rock reservoir, fracture-pore thermocontact metamorphic rock and irruptive rock compound reservoir, pore volcanic debris cone reservoir and fracture-pore overfall basaltic rock reservoir. The spatial distribution of each model's reservoir has its features. And reservoirs can be divided into primary ones and secondary ones, whose mechanism of formation and laws of distribution are studied in this paper. 3. Eight geologic factors which dominate igneous reservoirs are presented. The eight geologic factors which dominates igneous reservoirs are igneous facies, epigenetic tectonics deformation, fracture motion, intensity of intrusive effect and adjoining-rock characters, thermo-contact metamorphic rock facies, specific volcano-tectonic position, magmatic cyclicity and epigenetic diagenetic evolution. The interaction of the eight factors forms the four types nonhomogenous reservoir models of igneous reservoirs in Jiyang depression. And igneous facies and fracture motion are the most important and primary factors. 4. Identification patterns of seismic, well log and logging facies of igneous rocks are established. Igneous rocks of Jiyang depression show typical reflecting features on seismic profile. Tabular reflection seismic facies, arc reflection seismic facies and hummocky or mushroom reflection seismic facies are the three main facies. Logging response features of basic basalt and diabase are shown as typical "three low and two high", which means low natural gamma value, low interval transit-time, low neutron porosity, high resistivity and high density. Volcaniclastic rocks show "two high and three low"-high neutron porosity, high interval transit-time, low density, low-resistance and low natural gamma value. Thermo-contact metamorphic rocks surrounding to diabase show "four high and two low" on log data, which is high natural gamma value, high self-potential anomaly, high neutron porosity, high interval transit-time and low density and low-resistance. Based on seismic, well log and logging data, spatial shape of Shang 741 igneous rock is described. 5. The methods of fracture prediction and recognition for fractured igneous reservoir are summarized. Adopting FMI image log and nuclear magnetic resonance log to quantitative analysis of fractured igneous reservoir and according to formation mechanism and shape of fracture, various fractures are recognized, such as high-angle fracture, low-angle fracture, vertical fracture, reticulated fracture, induced fracture, infilling fracture and corrosion vug. Shang 741 intrusive rock reservoir can be divided into pore-vug compound type, pore fracture type, micro-pore and micro-fracture type. Physical properties parameters of the reservoir are computed and single-well fracture model and reservoir parameters model are established. 6. Various comprehensive methods of fracture prediction and recognition for fractured igneous reservoir are put forward. Adopting three-element (igneous facies, fracture motion and rock bending) geologic comprehensive reservoir evaluation technique and deep-shallow unconventional laterolog constrained inversion technique, lateral prediction of fractured reservoir such as Shang 741 is taken and nonhomogeneity quantification models of reservoirs are established.
Resumo:
Jiyang depression is one of the most important petroleum production basins in China. The petroleum pools, found easier, have been densely explored and developed. At present, the subtle traps are becoming the main exploring aims. A lot of Tertiary sand-conglomerate body petroleum pools, as one of the important subtle pools, have been discovered recently. It is necessary and urgent to study deeply the developing characteristics and petroleum pool distribution of Tertiary sand-conglomerate bodies in Jiyang Depression. The present dissertation has concluded the main developing characteristics of the Tertiary sand-conglomerate bodies in Jiyang Depression, and studied the sand-conglomerate bodies in Chengnan Fault Zone in detail. Depending on the synthesized studies of geology, geophysics and logging data, the following conclusions have been arrived at. Four criterion layers in Member 3 of Shahejie Formation, according to the depositional cycle analyses, have been established for the subdivision of different layers of sand-conglomerate bodies and the correlation of different sand-conglomerate bodies. It indicated that the alluvial delta, delta-fan, alluvial fan, shallow water fan , deep water turbidite , fan-front turbidite are the six kinds of sand-conglomerate bodies, which have been distinguished in Jiyang Depression with the study of genetic types, characteristics and distribution of sand-conglomerate bodies. The shallow water fan, steep slope deep water turbidite and fan-front turbidite were the main types of sand-conglomerate bodies developed in Chengnan steep slope. Their identification and distribution have been described in detail. The development and distribution of sand-conglomerate bodies were resulted by fault depressing, palco-climate change and channel or trough on the uplift. The fault depressing is the most important-factor to the episodic developing of sand-conglomerate bodies. An episodic developing genetic mode has been established by the contrast analyses between episodic fault depressing and climate change cycles. The hydrocarbon accumulation in the sand-conglomerate bodies in the steep slope was correlated with fan types, depositional phases, fault depressing and diagenesis. Sand-conglomerate wedge out (include up-oblique and onlap), lithological wedge out, mud screen (for anticline), fault plugging (by mud opposite sand, mud daubing) are the 5 possible mechanisms of oil accumulation. Lithological pool, stratigraphic pool and tectonic pool and lithologic-tectonic complex pool, and 9 subtypes of petroleum pools have been detected. It is easy for different pools to be combined as a complex reservoir, which was distributed along the syn-depositional fault slopes. The sand-conglomerate bodies in deep sag were usually evaluated as pore zone for hydrocarbon accumulation before. In fact, they are potential. Because of fan-front turbidite sands were especially developed in these zones, the sands have a close connection with the oil mud, and lithological pools can be expected to find in these zones. Chengnan fault slope was main channel of oil migration, and mud screen is the principle key for the oil accumulation in the sand-conglomerate bodies. If there was no mud between the sand-conglomerate bodies or on the top of sand-conglomerate bodies, the sand-conglomerate bodies would connect each other and there would be no dense material to hold up the oil migration along the slope. As the sand-conglomerate bodies could not been taken as a screen, the mud screen is the key for developing pool in this slope. According to this principle, about 6 potential traps, such as C915 block, C913 block, C916 block, south of Y109 well block, Y104 block and Y153 block, were selected for exploration and development.
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In this paper, the complex faulted-block oil reservoir of Xinzhen area in Dongying depression is systematically studied from basic conditions forming faulted-block oil and gas reservoir integrating geology, seismic, logging and reservoir engineering information and computer; guided by petroleum geology, geomechanics, structural geology and geophysics and other theories. Based on analysis of background condition such as regional strata, structure and petroleum geology, structural research on geometry, kinemaitcs and dynamics, oil-controlling fault research on the seal features, sealing mechanism and sealing pattern, and research on enrichment rules and controlling factors of complex faulted-block oil reservoir are carried out to give out the formation mechanics of oil reservoir of Xinzhen complex faulted-block oil reservoir. As a result, the reservoir formation pattern is established. At the same time, through dissecting the characteristics and hydrocarbon enrichment law of complex faulted-block oil reservoir, and studying its distribution law of remaining oil after entering extra high water-cut period, a set of technologies are formed to predict complex faulted-block oil reservoir and its remaining oil distribution and to enhance oil recovery (EOR). Based on the time relationship between migration of hydrocarbon and trap formation, accumulating period of Xinzhen oil reservoir is determined. The formation of Xinzhen anticlinal trap was prior to the primary migration. This is favorable to formation of Xinzhen anticlinal hydrocarbon reservoir. Meanwhile, because anticline top caving isn't at the sane time as that of moving or faulted-trap forming inner anticline, oil and gas migrated many times and Xinzhen complex faulted-block oil reservoir formed from ES_3~(upper) to EG. Accumulating law and controlling factors of complex faulted-block reservoir are analyzed from many aspects such as regional structure background controlling hydrocarbon accumulating, plastic arch-open structure controlling oil-bearing series and reservoir types, sealing-opening of fault controlling hydrocarbon distribution and structure pattern controlling enriched trap types. Also, we established the structure pattern in Xinzhen a'ea: the arch-open of underlying strata cause expanding fracture. The main block groups developed here are shovel-like normal fault block group in the north area of Xinzhen and its associated graben block group. Block groups dominate the formation and distribution of reservoirs. We studied qualitatively and quantitatively the sealing characteristics, sealing history and sealing mechanism of faults, too. And, the sealing characteristics are evaluated and the distribution pattern of hydrocarbon controlled by faults is researched. Due to movement intensity of big faults, deep falling of downthrown block, high degree of repture and development of fracture, shallow layers close to the downthrown block of secondary faults are unfavorable to hydrocarbon accumulation. This is confirmed by the exploration practice in Xinzhen anticline. In terms of the downthrown blocks of sencondary contemporaneous faults lied in the south and north area of Xinzhen, hydrocarbon is poor close to fracture belt, while it is relatively abundant in tertiary companion faults. Because of long-term movement of faults that control hydrocarbon, fi'om ES3 to EG, six set of oil-bearing series formed. And their opening causes the inhomogeneity in hydrocarbon abundance among each block--in two flanks of anticline reservoirs are abundant while in the axial area, oil and gas are sporadic. There the sealing characteristics control oil-bearing area of oil/gas accumulation and the height of oil reservoir. Longitudinally, oil and gas are enriched in dip-flat areas in mid-plane of faults. It is established that there are four types of accumulating patterns in complex faulted-block oil reservoirs in Xinzhen. The first is accumulating pattern of lithologic oil reservoirs in E~S_3~(mid-lowwer), that is, self-generating-self-reserving-self-covering lithologic trap pattern. The second is drag-anticline accumulating pattern in Xinzhen. The structure traps are drag anticlines formed by the contemporaneous faults of the second basement in the north of Xinzhen, and the multiple source rocks involve Ek_2, Es_4, Es_3 and Es_1 members. The reservoirs are fluvial-delta sandstones of the upper member of Shahejie formation and Guantao formation, covered by regional thick mudstone of the upper member of Guantao formation and MingHuazhen formation. The third is the accumulating pattern of reverse listric fault, the third-degree fault of Xinzhen anticline limb and the reservoirs form reservoir screened by reverse listric faults. The forth is accumulating pattern of crossing faults which form closing or semi-closing faulted-blocks that accumulate hydrocarbon. The technologies of predicting remaining oil in complex faulted-block reservoir during the mid and late development stage is formed. Remaining oil in simple large faulted-blocks enriches in structural high, structural middle, structural low of thick bottom water reservoirs, points near bent edge-fault oftertiary faults and part the fourth ones with big falling displacement, microstructure high place of oil-sandbodies and areas where local well pattern isn't perfect. While that in small complex faulted-blocks enriches near small nose, small high point, angle of small faults, small oil-bearing faulted-blocks without well and areas with non-perfect well pattern. The technologies of enhancing recovery factor in complex faulted-block reservoir during the mid and late development stage is formed as follows: fine reservoir description, drilling adjust wells, designing directional wells, sub-dividing layer series of development, improving flooding pattern, changing water-injection direction and enhancing swept volume, cyclic waterflooding and gas-injection, etc. Here, directional wells include directional deflecting wells, lateral-drilling wells, lateral-drilling horizontal wells and horizontal wells. The results of this paper have been used in exploration and development of Shengli oilfield, and have achieved great social and economic profit, especially in predicting distribution of complex faulted-block reservoir, remaining oil distribution during middle and late stage of development, and in EOR. Applying the achievement of fault-closure research, new hydrocarbon-bearing blocks are discovered in flanks of Dongying central uplift and in complex blocks with proved reserves 15 million tons. With the study of remaining oil distribution law in complex faulted-block reservoirs, recovery factors are increased greatly in Dongxin, Xianhe and Linpan complex faulted-block reservoirs and accumulated oil production increment is 3 million tons.
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The main research projects reported in this paper are the establishment of a luminescence (OSL/TL) dating laboratory in The Institute of Geology and Geophysics, CAS, and studies on OSL dating technique and protocol of sediments from North China. These projects have been suggested in order to fit in with the needs of research developments in environmental changes, in particular the aridity and desertification in North China. A new luminescence dating laboratory in which there are a Rise TL/OSL-DA-15B/C reader with Sr-90 beta source, a set of Little More Tape 9022 alpha and beta irradiators, three set of Daybreak 583 intelligent alpha counters and sample preparation system has been set up in the Institute in June 2001. The courses of the establishment of a new laboratory involved a series of technical works, besides making a suitable choice of the equipment, as follows: installing and testing TL/OSL reader, calibrating the dose rate of the beta and alpha sources in the irradiators with the standard sources, testing and calibrating the count rates of the thick source alpha counting in the alpha counters with a standard sample, and then dating of the know age samples to check and examine the OSL/TL dating system. All data obtained from above calibrations and tests show that the established OSL/TL system, including the used equipment in it, can be used to determine age of the geological and archaeological samples with an error of equivalent dose (De) of less than 5%. The OSL dates of several sediment samples obtained from the system are good agreement with those from the OSL dating laboratory in Hong Kong University and ~(14)C dates within 1 - 2 standard deviations. The studies on OSL dating technique and protocol of sediment samples being in progress involve the De determinations with single aliquot regeneration (SAR) (Murray and Wintle, 2000) of the coarse grain quartz from sand dune samples and comparison of the De determinations obtained from SAR with those measured by using multiple aliquot regeneration of loess fine grains. The preliminary results from these research works are shown as follows. The very low natural equivalent dose (De) of about 0.012 - 0.03 Gy, corresponding age of less than 10 years, for BLSL (blue light stimulated luminescence) of the coarse grain quartz from modern sand dune samples in Horqin sand fields has been determined with both the SAR and multiple aliquot regeneration (MAR) techniques. This imply that the BLSL signal zeroing of the quartz could be reached before burying of the sand in Horqin sand fields. The De values and ages of the coarse grain quartz measured with SAR protocol are in good agreement with those obtained from multiple aliquot technique for the modern sand dune samples, but the errors of De from the MAR is greater than those from the SAR. This may imply that the higher precision of age determination for younger sand dune samples could be achieved with the SAR of coarse grain quartz. The MAR combining with "Australian Slide method" may be a perfect choice for De measurements of loess fine grain samples on the basis of analysis of De values obtained from the SAR and from the MAR. The former can be employed to obtain a reliable age estimate of loess sample as older as approximately SO ka BR There is a great difference between De determinations from the (post-IR) OSL of the SAR (Roberts and Wintle, 2001) and those from independent or expected estimates for the older samples. However, the age estimates obtained from the (post-IR) OSL of the SAR are mostly closed to the independent age determinations for the younger (age less than 10 ka) fine grain samples. It may be suggested that the (post-IR) OSL of the SAR protocol of the fine grain fraction would be a suitable choice to dating of the younger samples, but may be unsuitable for the older samples.
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Under the auspices of the 'knowledge-Innovation Program' of CAS, Institute of Geology and Geophysics has established the Broadband Seismic Laboratory. A new kind of 24-bit high-resolution seismograph DAS24-3B has been designed and manufactured in an effort of developing China's own technology of seismic array. Since these instruments will primarily be used in field operation, there is a need to optimize the system software of data acquisition system (DAS) to enhance its stability, compatibility and maintenance. The design ideas of the system software of DAS24-3B are partly learned from the advanced DAS 72A-08. In this system there are two exclusive communication programs DNAPI-COM1 and DNAPI-LPT1, which are suitable for all standard industrial computers with ECP parallel port and serial port. By these exclusive parallel and serial communication interface the system software is split into three parts, acquisition program, user's control program and graphical display program, which can function well in separate units and can run correctly in whole. The three parts of DAS24-3B's system software possess different functions and advantages. The function of acquisition program is to control the process of seismic data acquisition. DAS24-3B system reduced its power and harddisk read-write disturbance by using the extended memory attached to its CPU, which functions as enlarging the data buffer of system and lessening the times of harddisk read-write operations. Since GPS receiver of DAS is strongly sensitive to the around environment and has the possibility of signal loss the acquisition program has been designed with the ability to automatically trail the GPS locked time. The function of user's controlling program is to configure the system's work environment, to inform the user's commands to DAS, to trail the status of DAS in real-time. The function of graphical display program is to illustrate data in figures, to convert data file into some common formatted file, to split data file in parts and combine data files into one. Both user's control program and graphical display program are API (Application Programming Interface) in window 95/98 system. Both possess the features of clearness and friendship by use of all kind of window controls, which are composed by menu, toolbar, statusbar, dialogue box, message box, edit box, scrollbar, time control, button and so on. Two programs of systemic exception handles are provided to treat the trouble in field. The DAS24-3B DAS has been designed to be easier to use-better ability, more stable and simpler. It has been tested in field and base station and has been proved more suitable for field operation of seismic array than other native instruments.
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As a marginal subject, dynamic responses of slopes is not only an important problem of engineering geology (Geotechnical problem), but also of other subjects such as seismology, geophysics, seismic engineering and engineering seismic and so on. Owning to the gulf between different subjects, it is arduous to study dynamic responses of slopes and the study is far from ripeness. Studying on the dynamic responses of slopes is very important in theories as well as practices. Supported by hundreds of bibliographies, this paper systemically details the development process of this subject, introduces main means to analyze this subject, and then gives brief remarks to each means respectively. Engineering geology qualitative analysis is the base of slopes dynamic responses study. Because of complexity of geological conditions, engineering geology qualitative analysis is very important in slopes stability study, especially to rock slopes with complex engineering geology conditions. Based on research fruits of forerunners, this paper summarizes factors influencing slopes dynamic stability into five aspects as geology background, stratums, rock mass structure, and topography as well as hydrogeology condition. Based on rock mass structure controlling theory, engineering geology model of the slope is grouped into two typical classes, one is model with obvious controlling discontinuities, which includes horizontal bedded slope, bedding slope, anti-dip slope, slide as well as slope with base rock and weathered crust; the other is model without obvious controlling discontinuities, which includes homogeneous soil slope, joint rock mass slope. Study on slope failure mechanism under dynamic force, the paper concludes that there are two effects will appear in slope during strong earthquake, one is earthquake inertia force, the other is ultra pore pressure buildup. The two effects lead to failure of the slope. To different types of slope failure, the intensity of two effects acting on the slope is different too. To plastic flow failure, pore pressure buildup is dominant; to falling rock failure and toppling failure, earthquake inertia force is dominant in general. This paper briefly introduces the principle of Lagrangian element method. Through a lot of numerical simulations with FLAC3D, the paper comprehensively studies dynamic responses of slopes, and finds that: if the slope is low, displacement, velocity and acceleration are linear enlarging with elevation increasing in vertical direction; if the slope is high enough, displacement, velocity and acceleration are not linear with elevation any more, on the other hand, they fluctuate with certain rhythm. At the same time, the rhythm appears in the horizontal direction in the certain area near surface of the slope. The distribution form of isoline of displacement, velocity and acceleration in the section of the slope is remarkably affected by the slope angle. In the certain area near the slope surface, isoline of displacement, velocity and acceleration is parallel to the surface of the slope, in the mean time, the strike direction of the extreraum area is parallel to the surface of the slope too. Beyond this area, the isoline direction and the strike direction of the extremum area turn to horizontal with invariable distance. But the rhythm appearing or not has nothing to with the slope angle. The paper defines the high slope effect and the low slope effect of slopes dynamic responses, discusses the threshold height H^t of the dynamic high slope effect, and finds that AW is proportional to square root of the dynamic elastic moduli El P , at the same time, it is proportional to period Tof the dynamic input. Thus, the discriminant of H^t is achieved. The discriminant can tell us that to a slope, if its height is larger than one fifth of the wavelength, its response regular will be the dynamic high slope effect; on the other hand, its response regular will be the dynamic low slope effect. Based on these, the discriminant of different slopes taking on same response under the same dynamic input is put forward in this paper. At the same time, the paper studies distribution law of the rhythm extremum point of displacement, velocity and acceleration, and finds that there exists relationship of N = int among the slope height H, the number of the rhythm extremum
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point N and ffthre- Furthermore, the paper points out that if N^l, the response of the slope will be dynamic high slope effect; \fN
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This paper is belonging to Chinese Petrochemical Industry Corporation's key project. Although it is very difficult, it has important theoretical and practical value. Its targets is to make lithological petroleum pool exploration great breakthrough in Dongying sag, by applying advanced theories, the last-minute methods and technology in highly explored zones. By using synthetically multi- discipline theories, methods and technology such as petroleum geology, sedimentology, structure geology, rock mechanics, dynamics of petroleum pool formation, geochemistry, geophysics and so on, and by making full use of computer , the process of petroleum pool forming and distribution rules of lithological petroleum pools have been thoroughly investigated and analyzed in sharp-slope, gentle-slope as well as low-lying region of Dongying sag including dynamic and static. With the study of tectonic stress field, fluid potential field and pressure field, we revealed dynamics condition, distribution rule, control factors and petroleum forming mechanism of lithological pool, and established the forming mode of lithological pool of Dongying sag. The main conclusion as follow: Strata framework, structure framework and sedimentary system of Dongying sag have been established which were the basis of petroleum prediction. There are three kinds of oil source which were from Es4,Es3 and mixed type, also three petroleum forming phases which were the telophase of Dongying stage, Guantao stage and Minghuazhen group, which occur in different geological environment. By using of most advanced numerical modeling software, the space distribution and time evolve of stress field and fluid potential field have been revealed from Esl up to the present. The region with low earth stress and low fluid potential were enrichment region of lithological petroleum pool and fault-block pool. The dynamics mechanism of Lithological petroleum pool in Dongying sag was collocating seal box, abnormity pressure, index number of petroleum forming and static factors on time and space, which was the most important factor of controlling petroleum pool forming, distribution and enrichment. The multi phase active and evolve of seal and unseal about different order fault were main factors of controlling petroleum pool forming of Dongying sag, which have important value for predicting lithological petroleum pool. It is revealed the lithological petroleum pool forming mode that included respective character, forming mechanism and distribution rule in four structural belt, which was a base for lithological petroleum pool prediction. The theories, technology and methods of studying, description, characterize and prediction lithological petroleum pool were established, which have important popularization value. Several lithological pool have been predicted in stress transform, zone, abrupt slope zone, fractured surface changed zone, tosional stress growth zone and abnormity pressure zone with noticeable economic benefit after exploration.
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As the largest and highest plateau on the Earth, the Tibetan Plateau has been a key location for understanding the processes of mountain building and plateau formation during India-Asia continent-continent collision. As the front-end of the collision, the geological structure of eastern Tibetan Plateau is very complex. It is ideal as a natural laboratory for investigating the formation and evolution of the Tibetan Plateau. Institute of Geophysics, Chinese Academy of Sciences (CAS) carried out MT survey from XiaZayii to Qingshuihe in the east part of the plateau in 1998. After error analysis and distortion analysis, the Non-linear Conjugate Gradient inversion(NLCG), Rapid Relaxation Inversin (RRI) and 2D OCCAM Inversion algorithms were used to invert the data. The three models obtained from 3 algorithms provided similar electrical structure and the NLCG model fit the observed data better than the other two models. According to the analysis of skin depth, the exploration depth of MT in Tibet is much more shallow than in stable continent. For example, the Schmucker depth at period 100s is less than 50km in Tibet, but more than 100km in Canadian Shield. There is a high conductivity layer at the depth of several kilometers beneath middle Qiangtang terrane, and almost 30 kilometers beneath northern Qiangtang terrane. The sensitivity analysis of the data predicates that the depth and resistivity of the crustal high conductivity layer are reliable. The MT results provide a high conductivity layer at 20~40km depth, where the seismic data show a low velocity zone. The experiments show that the rock will dehydrate and partially melt in the relative temperature and pressure. Fluids originated from dehydration and partial melting will seriously change rheological characteristics of rock. Therefore, This layer with low velocity and high conductivity layer in the crust is a weak layer. There is a low velocity path at the depth of 90-110 km beneath southeastern Tibetan Plateau and adjacent areas from seismology results. The analysis on the temperature and rheological property of the lithosphere show that the low velocity path is also weak. GPS measurements and the numerical simulation of the crust-mantle deformation show that the movement rate is different for different terranes. The regional strike derived from decomposition analysis for different frequency band and seismic anisotropy indicate that the crust and upper mantle move separately instead of as a whole. There are material flow in the eastern and southeastern Tibetan Plateau. Therefore, the faults, the crustal and upper mantle weak layers are three different boundaries for relatively movement. Those results support the "two layer wedge plates" geodynamic model on Tibetan formation and evolution.
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By applying synthetically multi-subject theories, methods and technology, such as petroleum geology, sedimentology, seep mechanics, geochemistry, geophysics and so on; and by making full use of computer; combining quantity and quality, macroscopic and microscopic, intensive static and active description, comprehensive studying and physical modeling, 3 dimension and 4 dimension description; the paper took Wen-33 block of Zhongyuan oil field as an example; and studied reservoir macroscopic and microscopic parameter changing rule and evolve mechanics in different water-blood stage. The reservoir dynamic model and remaining-oil distribution mode was established, and several results were achieved as follows: (1) Three types of parameter gaining, optimizing and whole data body of Wen33th reservoir were established. Strata framework, structure framework, reservoir types and distribution of Wen33th reservoir were discussed. Reservoir genesis types, space distribution law and evolve rule of Wen33th reservoir were explained. 4D dynamic model of macroscopic parameter of reservoir flow dynamic geologic function of Wen33th reservoir was established. The macroscopic remaining-oil distribution and control factor was revealed. The models of the microscopic matrix field, pore-throat network field, fluid field, clay mineral field of Wen-33 block were established. The characters, changing rules and controlled factors in different water stage were revealed. The evolve rule and mechanics of petroleum fluid field in Wen-33 block reservoir were revealed. Macroscopic and microscopic remaining oil distribution mode of Wen-33 block were established. Seven types, namely 12 shapes of dynamic model of microscopic remaining oil were discussed, and the distribution of mover remaining oil was predicted. Emulation model: mathematical model and prediction model of Wen-33 block were established. The changing mechanics of reservoir parameter and distribution of remaining-oil were predicted. Firstly, the paper putting forward that the dynamic geologic function of petroleum development is the factor of controlling remaining-oil, which is the main factor leading to matrix field, network field, clay mineral field, fluid field, physic and chemical field, stress field and fluid field forming and evolving. (10) A set of theories, methods and technologies of investigating, describing, characterizing and predicting complex fault-block petroleum were developed.
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In this paper, we have presented the combined preconditioner which is derived from k =±-1~(1/2) circulant extensions of the real symmetric positive-definite Toeplitz matrices, proved it with great efficiency and stability and shown that it is easy to make error analysis and to remove the boundary effect with the combined preconditioner. This paper has also presented the methods for the direct and inverse computation of the real Toeplitz sets of equations and discussed many problems correspondingly, especially replaced the Toeplitz matrices with the combined preconditoners for analysis. The paper has also discussed the spectral analysis and boundary effect. Finally, as an application in geophysics, the paper makes some discussion about the squared root of a real matrix which comes from the Laplace algorithm.
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With the development of oil and gas exploration, the exploration of the continental oil and gas turns into the exploration of the subtle oil and gas reservoirs from the structural oil and gas reservoirs in China. The reserves of the found subtle oil and gas reservoirs account for more than 60 percent of the in the discovered oil and gas reserves. Exploration of the subtle oil and gas reservoirs is becoming more and more important and can be taken as the main orientation for the increase of the oil and gas reserves. The characteristics of the continental sedimentary facies determine the complexities of the lithological exploration. Most of the continental rift basins in East China have entered exploration stages of medium and high maturity. Although the quality of the seismic data is relatively good, this areas have the characteristics of the thin sand thickness, small faults, small range of the stratum. It requests that the seismic data have high resolution. It is a important task how to improve the signal/noise ratio of the high frequency of seismic data. In West China, there are the complex landforms, the deep embedding the targets of the prospecting, the complex geological constructs, many ruptures, small range of the traps, the low rock properties, many high pressure stratums and difficulties of boring well. Those represent low signal/noise ratio and complex kinds of noise in the seismic records. This needs to develop the method and technique of the noise attenuation in the data acquisition and processing. So that, oil and gas explorations need the high resolution technique of the geophysics in order to solve the implementation of the oil resources strategy for keep oil production and reserves stable in Ease China and developing the crude production and reserves in West China. High signal/noise ratio of seismic data is the basis. It is impossible to realize for the high resolution and high fidelity without the high signal/noise ratio. We play emphasis on many researches based on the structure analysis for improving signal/noise ratio of the complex areas. Several methods are put forward for noise attenuation to truly reflect the geological features. Those can reflect the geological structures, keep the edges of geological construction and improve the identifications of the oil and gas traps. The ideas of emphasize the foundation, give prominence to innovate, and pay attention to application runs through the paper. The dip-scanning method as the center of the scanned point inevitably blurs the edges of geological features, such as fault and fractures. We develop the new dip scanning method in the shap of end with two sides scanning to solve this problem. We bring forward the methods of signal estimation with the coherence, seismic wave characteristc with coherence, the most homogeneous dip-sanning for the noise attenuation using the new dip-scanning method. They can keep the geological characters, suppress the random noise and improve the s/n ratio and resolution. The rutine dip-scanning is in the time-space domain. Anew method of dip-scanning in the frequency-wavenumber domain for the noise attenuation is put forward. It use the quality of distinguishing between different dip events of the reflection in f-k domain. It can reduce the noise and gain the dip information. We describe a methodology for studying and developing filtering methods based on differential equations. It transforms the filtering equations in the frequency domain or the f-k domain into time or time-space domains, and uses a finite-difference algorithm to solve these equations. This method does not require that seismic data be stationary, so their parameters can vary at every temporal and spatial point. That enhances the adaptability of the filter. It is computationally efficient. We put forward a method of matching pursuits for the noise suppression. This method decomposes any signal into a linear expansion of waveforms that are selected from a redundant dictionary of functions. These waveforms are chosen in order to best match the signal structures. It can extract the effective signal from the noisy signal and reduce the noise. We introduce the beamforming filtering method for the noise elimination. Real seismic data processing shows that it is effective in attenuating multiples and internal multiples. The s/n ratio and resolution are improved. The effective signals have the high fidelity. Through calculating in the theoretic model and applying it to the real seismic data processing, it is proved that the methods in this paper can effectively suppress the random noise, eliminate the cohence noise, and improve the resolution of the seismic data. Their practicability is very better. And the effect is very obvious.