保重心脉冲压缩滤波及其在速度自动拾取中的应用

To pick velocity automatically is not only helpful to improve the efficiency of seismic data process, but also to provide quickly the initial velocity for prestack depth migration. In this thesis, we use the Viterbi algorithm to do automatic picking, but the velocity picked usually is immoderate. By thorough study and analysis, we think that the Viterbi algorithm has the function to do quickly and effectually automatic picking, but the data provided for picking maybe not continuous on derivative of its curved surface, viz., the curved face on velocity spectrum is not slick. Therefore, the velocity picked may include irrational velocity information. To solve the problem above, we develop a new method to filter signal by performing nonlinear transformation of coordinate and filter of function. Here, we call it as Gravity Center Preserved Pulse Compressed Filter (GCPPCF). The main idea to perform the GCPPCF as follows: separating a curve, such as a pulse, to several subsection, calculating the gravity center (coordinate displacement), and then assign the value (density) on the subsection to gravity center. When gravity center departure away from center of its subsection, the value assigned to gravity center is smaller than the actual one, but non other than gravity center anastomoses fully with its subsection center, the assigned value equal to the actual one. By doing so, the curve shape under new coordinate breadthwise narrows down compare to its original one. It is a process of nonlinear transformation of coordinate, due to gravity center changing with the shape of subsection. Furthermore, the gravity function is filter one, because it is a cause of filtering that the value assigned from subsection center to gravity center is obtained by calculating its weight mean of subsetion function. In addition, the filter has the properties of the adaptive time delay changed filter, owing to the weight coefficient used for weight mean also changes with the shape of subsection. In this thesis, the Viterbi algorithm inducted, being applied to auto pick the stack velocity, makes the rule to integral the max velocity spectrum ("energy group") forward and to get the optimal solution in recursion backward. It is a convenient tool to pick automatically velocity. The GCPPCF above not only can be used to preserve the position of peak value and compress the velocity spectrum, but also can be used as adaptive time delay changed filter to smooth object curved line or curved face. We apply it to smooth variable of sequence observed to get a favourable source data ta provide for achieving the final exact resolution. If there is no the adaptive time delay-changed filter to perform optimization, we can't get a finer source data and also can't valid velocity information, moreover, if there is no the Viterbi algorithm to do shortcut searching, we can't pick velocity automatically. Accordingly, combination of both of algorithm is to make an effective method to do automatic picking. We apply the method of automatic picking velocity to do velocity analysis of the wavefield extrapolated. The results calculated show that the imaging effect of deep layer with the wavefield extrapolated was improved dominantly. The GCPPCF above has achieved a good effect in application. It not only can be used to optimize and smooth velocity spectrum, but also can be used to perform a correlated process for other type of signal. The method of automatic picking velocity developed in this thesis has obtained favorable result by applying it to calculate single model, complicated model (Marmousi model) and also the practical data. The results show that it not only has feasibility, but also practicability.

东营凹陷沙三中亚段湖相浊积岩储层特征及油气成藏规律研究

Turbidity sandstone reservoirs have been an important field of hydrocarbon exploration and development in the basins all over the world, as well as in China. Lithologic pools are composed of turbidity sandstones and other sandstones are frequently found in the Jiyang Depression that is a Mesozoic-Cenozoic non-marine oil-bearing basin. The Dongying Sag lies in the sedimentary center of the basin. The subtle traps with turbidity reservoirs are generally difficult to be predicted and described by using current techniques. The studies on turbidity reservoirs plays thus an important theoretical and theoretical practical role in exploration and development in the Jiyang Depression. The attention is, in this thesis, focused on the petrologic properties and oil accumulating behaviors in lake turbidity sedimentary systems in the middle part of the third section of Shahejie Formation in the Dongying Sag, especially in Dongxin area, which lies on the central uplift of the Sag. The paper has disclosed the origin types of turbidity sandstones, distribution pattern and controlling factors of turbidity sandstones, and set up hydrocarbon accumulation patterns of the middle part of the third section of Shahejie Formation in Dongxin, based on nonmarine high resolution sequence stratigraphy, event sedimentology and new theories of hydrocarbon forming. By studying prediction method and technology of turbidity sandstone reservoirs, using precise geological model developing, new techniques of high resolution seismic inversion constrained by logging, the paper has forecast low permeability turbidity sandstone reservoirs and pointed out advantage exploration aims to progressive exploration and development. The paper has obtained mainly many productions and acknowledges as follows: 1.Turbidity sandstone reservoirs of the third section of Shahejie Formationin Dongying Sag are formed in such specifical geological background as rift and extension of basin. The inherited Dongying delta and transgression make up many turbidity distribution areas by overlaying and joining together. The hydrocarbon migrates from depression area to adjacent turbidity sandstone continuously. Accumulation area which is sufficient in oil is formed. 2.The paper has confirmed distinguishable sign of sequence boundary , established stratigraphic framework of Dongying Sag and realized isotime stratigraphic correlation. Es3 of Dongying delta is divided into eleven stages. Among them, the second period of the lower section in Es3, the sixth period of the middle section in Es3, the third period of the upper section in Es3 correspond to eleven sedimentary isotime surface in seismic profile, namely Es3 is classified into eleven Formations. 3.According to such the features of turbidity sandstone as deep in burial, small in area, strong in subtle property, overlaying and joining together and occurring in groups, management through fault and space variations of restriction quantum are realized and the forecast precision of turbidity sandstone by using precise geological model developing, new techniques of high resolution seismic inversion constrained by logging, based on the analysis of all kinds of interwell seismic inversion techniques. 4.According to the features of low permeable turbidity sandstone reservoirs, new method of log interpretation model is put forward. At the same time, distinguish technology of familiar low resistivity oil layer in the turbidity sandstone reservoirs is studied based on petrophysical laboratory work and "four properties" interrelationship between lithological physical Jogging and bearing hydrocarbon properties. Log interpretation model and reservoir index interpretation model of low resistivity oil layer are set up. So the log interpretation precision is improved. 5.The evolution law and its difference of the turbidity sandstone are embodies as follows: the source of sediments come from the south and east of the study area in the middle period of Es3. East source of sediments is pushed from west to east. However, the south source supply of sediments in the early and middle period of Es3 is in full, especially in Es3. subsequently, the supply is decreased gradually. Turbidity fan moves back toward the south and the size of fan is minished accordingly. The characteristic of turbidity sandstone in Dongying Sag is different in different structural positions. Dongxin in the middle-east of the central lift and Niuzhuang Sag He in Dongying delta front and prodelta deep lake subfacies. Although the turbidity sandstone of the two areas root in the Dongying delta sedimentary system, the sand body has different remarkably characteristic. 6.The sedimentary model of the turbiditys in study area have three types as follows: (1) collapse turbidity fan in respect of delta; (2) fault trench turbidity fan; (3) other types of microturbidity sandstone. Middle fan and outer fan, can be found mainly in sublacustrine fan. Middle fan includes braided channel microfacies, central microfacies and braided interchannel microfacies, which is main prospecting oil-bearing subfacies. The middle section of the third section of Shahejie Formation in study area (for example the central lift) can be divided into middle-lower and upper part. The middle-lower part is characteristic of turbidity fan. The upper part is sedimented mainly by delta-collapse fan. 7.The turbidity reservoirs of the middle part of the third section of Shahejie Formation in study area characterize by low maturity both in component and texture, strong in diagenesis and low in permeability. The reservoir can be classified into four types. Type III is the body of reservoir and comprises two types of H a and HI b. M a belongs to middle porosity - low permeability reservoir and distributes in the central lift. Hlb belongs to low porosity - low permeability and distributes in Haojia region. 8.A11 single sand body of lens turbidity reservoir of the middle part of the third section of Shahejie Formation in study area are surrounded by thick dark source rocks. The oil-water system is complex and behaves that every sandstone is single seal unit. The water body is 1/3-1-5 of the sand body. The edge water is not active. The gas exists in the top of reservoir in the form of mixed gas. For far-range turbidity fan with big scale channel, the area and volume of sand body is large and the gap is big in oil packing degree. There are lots of edge water and bottom water, and the latter increases rapidly during the course of development. 9.By exerting the modern hydrocarbon forming theories, the third section of Shahejie Formation in study area belongs to abnormally pressured fluid compartment. The lithological reservoir of the third section of Shahejie Formation is formed in the compartment. The reservoir-formed dynamic system belongs to lower self-source enclosed type. The result and the practice indicate that the form and accumulation of lithological oil reservoirs are controlled by the temperature and pressure of stratum, microfacies, thickness of sand body, fault and reservoir heterogeneity. 10. Based on studies above, the emphases focus on in south and north part of Dongying structure, west Dongxin region and south part Xinzhen structure in the application of production. The practice proves that the turbidity sandstone reservoirs in Ying 11 block and the fault-lithological reservoirs in Xin 133 block have been obtained significant breakthrough. The next target is still sandstone groups of the third section of Shahejie Formation in the bordering areas of Dongxin region for instance Xin 149 area, He 89 area, Ying 8 area etc.

济阳地区深部结构与含油气性讨论

Oil and gas exploration of marine strata in China's Pre-Cenozoic residual basins is regarded as a worldwide puzzle because of existent problems and cruxes. Objectively speaking, the subsurface geologic structure is complicated, and the surface conditions of some areas are tough. On the other hand, there are still many problems to be solved in oil and gas exploration technologies of Pre-Cenozoic marine fades, and theoretic cognition about petroleum geology is not profound yet. Therefore, it is principal to explore integrated geophysical research ways of Pre-Cenozoic residual basins. Seismic prospecting and geophysical integrated interpretation technologies aimed at middle Paleozoic marine facies with deeper burial and complicated geologic conditions have not formed due to bad quality of deep strata data. Pre-Cenozoic strata, and especially extension, thickness and internal structure of Paleozoic strata can not be recognized from seismic profiles, so it is hard to systematically cognize structural features and oil-gas resources prospect of Pre-Cenozoic basins. To further investigation of fabric and structural features, basin prototype, formation and evolution pattern of Pre-Cenozoic basins, and also their control over formation, migration and aggregation of oil and gas, will play a guiding and promotive role in developing new surveying areas, selecting advantageous zones and predicting oil-gas resources.This paper follows the modem macrocontrol theory of "Region constrains local, deep strata controls shallow ones", and uses the integrated geophysical method of "One guide, two hinges, three combinations and multi feedbacks'*. Based on several years of geological and geophysical results of the Shengli Oilfield, and 14 newly-joint regional seismic profiles, deep structure and oil-gas bearing capacity of the Jiyang area are discussed and new cognitions are drawn as below.Seismic identification marks Tr, Tg, Tgl and Tg2 are established for importantPre-Cenozoic geological interfaces, and promoted to the whole Jiyang area.Through area-wide tracking and clogging of important seismic reflection marker,the isochronic framework of pre-Tertiary basin is set up in the Jiyang area for the firsttime, which is vital for basin research.Integrated with geological and geophysical research results, the Jiyang area isdivided into four first-order tectonic sequences- basement, lower tectonic layer,upper tectonic layer, and top tectonic layer. The basement and lower tectonic sequence which are related to Pre-Cenozoic are studied with emphasis.Through the research of regional seismic profiles, the point of view is given thatthe Kongdian Formation of Jiyang is structural transition period. The top-bottomunconformable interface of the Kongdian Formation is found out for the first time,and the basin model is determined primarily, which lay a basis for prototype basinresearch of the Jiyang Kongdian Formation.The distribution status of Middle-Paleozoic is delineated in the Jiyang area.The maximum thickness of Paleozoic lies in the top of the south declivity of half-graben. The thickness gets thinner towards the center of Mesozoic and Cenozoic half-graben basin, and even disappears. Structural action in the west-north affects the distribution of Paleozoic residual strata.6. The features of second-order tectonic sequence of the Jiyang depression isstudied and its evolution history of is rebuilt.Combined with the 5-stage evolution history of the China continent and structure evolution features of the Jiyang area, the structure sedimentary process since Paleozoic is divided into 5 periods - basement forming , Indosinian orogenic, Yanshan negative reversal, Himalayan extension and Neogene subsidence period.Combined with the research results of gravity, magnetic surveying and regionalprofiles, this paper brings forward the idea for the first time that the western boundaryof the Jiyang depression is the Ningjin-Yangpan fracture zone, and forms aside-column assemblage with the Wudi fracture zone.The opinion that under Middle-Cenozoic basins in the middle Jiyang area theremight superimpose an old residual basin is given for the first time. And if it is provedto be true, a new exploration space will be pioneered for Jiyang and even north China.There exists many types of tectonic-stratigraphic traps formed under piezotropy,extension and compound action in Pre-Cenozoic Jiyang. Therein all kinds of burialhills are the most important oil-gas trap type of Pre-Cenozoic, which should besurveyed layeredly according to the layout of oil sources.As such a new challenging project and field, the paper systematically analyses different geophysical responses of the Jiyang area, frames the deep structure of the area, and preliminarily recognizes the Pre-Cenozoic residual basins. It breaks through to a certain extent in both theory and practice, and is expected to provide new geophysical and geotectonic clues for deep exploration in Shengli.