Method for structure-multiple attribute tectonic palaeogeographic reconstruction of deep buried area of superimposed basin

Abstract

The present application relates to the field of basin forming dynamics and oil exploration technology, in particular to a method for structure-multiple attribute tectonic palaeogeographic reconstruction of deep buried area of superimposed basin, establishing outcrop area and drilling stratum sequence framework and sedimentary facies model; determining vertical structure-stratigraphic unit of deep buried area of superimposed basin; determining spatial distribution of unconformity structure of deep buried area under single tectonic movement; determining main palaeoactive fault and magmatic activity of deep buried area; identifying and determining spatial distribution of seismic stratigraphic characteristics and attributes in single structure-stratigraphic unit; reconstructing tectonic palaeogeography of deep buried area of superimposed basin under single tectonic movement, using outcrop data, drilling and logging data, etc. to carry out comprehensive geology and geophysical analysis, using basin structure and geophysical multiple attributes in different periods to restore tectonic palaeogeography of deep buried area, and providing scientific, reliable and high-precision evidence for cognition and resource exploration of deep and ultra-deep layers under the double conditions of mutual constraint of palaeostructure and palaeogeography.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of basin formation dynamics and oil exploration technology, in particular to a method for structure-multiple attribute tectonic paleogeographic reconstruction in deep buried area of superimposed basin. BACKGROUND

[0002] Tectonic paleogeographic research is the reconstruction of paleogeography under the control of multi-scale tectonics from plate tectonics to intrabasin tectonics, which reflects the constraints of basin formation dynamics on tectonic-sedimentary strata development. The tectonic paleogeographic reconstruction of the deep buried area of superimposed basin is a reshaping of the development process of the extremely poorly understood deep basin, which clarifies the tectonic-sedimentary development and genesis, and has great economic significance for deep and ultra-deep oil and gas resource potential evaluation and new field oil and gas exploration.

[0003] Current international paleogeography is mainly guided by plate tectonics theory, relying on paleomagnetism, paleontology and geochemistry to reconstruct the position of continents, plate boundaries and sea-land distribution during the geological history, and to restore plate tectonic paleogeography on the scale of plate. It emphasizes the analysis of paleogeographic changes from the time scale of the earth, and gradually integrates tectonics, topography, climate change, basin-mountain coupling, source-sink system, catchment basin characteristics, paleontology and paleo-ocean into paleogeographic research (Hall, 2009; Kanygin et al., 2009; Li Jianghai and Jiang Hongfu, 2013; Chen Hongde et al., 2017). Chinese paleogeography research began in the 1930s, and then Feng Zengzhao (1988, 2004, 2007, 2016) proposed the single factor analysis and multi-factor comprehensive mapping method to establish quantitative paleogeographic maps by dividing into paleocontinent and paleo-ocean, basin and platform, beach, set, flat, lake and reef. Wang Hongzhen (1985, 1990) used the "activity theory" of global tectonics and the "stage theory" of historical evolution as a guide, and compiled global paleocontinent reconstruction maps for the Sino-Korean, Yangtze and Tarim platforms with the help of paleomagnetic polarity curves. There are also paleogeography and paleoenvironment recovery under the coupling of deep earth processes and earth surface systems, and restoration of different geological period prototype basins, which are more based on stratigraphic development, biological fossils and sedimentary filling characteristics for lithofacies paleogeographic restoration, and serve for mineral resource exploration.

[0004] But the previous lithofacies paleogeographic mapping, often using a large number of field outcrops and drilling data, but due to the difference in drilling density, the area not revealed by drilling is difficult to form high-quality paleogeographic map, especially lack of contemporaneous tectonic control. And for the deep buried area of the superimposed basin, due to the unclear distribution of the prototype basin and the uncertain preservation of the residual basin, combined with the few drilling data, the paleogeographic map is mostly medium and small scale, which causes most of the regions to be almost data and material supported speculation and extension, and it is difficult to provide scientific, direct and practical evidence for deep resource evaluation.

[0005] Therefore, the present application designs a structure-multiple attribute tectonic paleogeographic reconstruction method for deep buried area of superimposed basin. On the basis of paleostructure recovery, the method qualitatively and semi-quantitatively reconstructs the paleogeography of deep buried area in different periods. SUMMARY

[0006] The purpose of the present application is to fill the gap in the prior art, and provide a structure-multiple attribute tectonic paleogeographic reconstruction method for deep buried area of superimposed basin. On the basis of paleostructure recovery, the method qualitatively and semi-quantitatively reconstructs the paleogeography of deep buried area in different periods.

[0007] In order to achieve the above purpose, the present application provides a structure-multiple attribute tectonic paleogeographic reconstruction method for deep buried area of superimposed basin, comprising the following steps:

[0008] S1, establishing outcrop area and drilling stratigraphic sequence framework and sedimentary facies model;

[0009] S2, determining the vertical structure-stratigraphic unit of the deep buried area of the superimposed basin;

[0010] S3, determining the spatial distribution of unconformity structure under single tectonic movement in the deep buried area;

[0011] S4, determining the main paleoactive fault and magmatic activity in the deep buried area;

[0012] S5, identifying and determining the spatial distribution of seismic stratigraphic characteristics and seismic attributes in the single structure-stratigraphic unit;

[0013] S6, reconstructing the tectonic paleogeography of the superimposed basin under single tectonic movement according to S3, S4 and S5.

[0014] Step S1: According to the field geological survey of the outcrop profile of the basin edge, the regional unconformity and local unconformity are identified and determined, the regional unconformity is taken as the boundary of the stratigraphic sequence framework, the petrological and sedimentological characteristics of the stratigraphic sequence are analyzed, and the sedimentary facies model is established.

[0015] Step S2 is: comparing the development characteristics of the stratigraphic sequences in the outcrop area, combining the comprehensive analysis of the drilling, logging and seismic data in the basin, establishing the stratigraphic sequence framework which can be compared in the outcrop area and downhole; determining the tecto-stratigraphic units in the deep buried area according to the main tectonic movement stages.

[0016] Step S3 is: according to the tecto-stratigraphic unit division scheme, using the drilling, logging and seismic data, making the synthetic seismogram, determining the tecto-stratigraphic units on the cross-well section, and developing the identification and interpretation of the tecto-stratigraphic units in the deep buried area, carrying out the main unconformity ternary structure tectonic interpretation, including the systematic analysis of the tectonic deformation of the underlying strata of the unconformity, the planar distribution of the unconformity structure type, the sedimentary structure and the initial sediments of the overlying strata of the unconformity and their sources; using the layer flattening method to qualitatively and semi-quantitatively further identify and analyze the main unconformity structure types and deformation characteristics in the deep buried area, respectively marking them on the plan view, and determining the spatial distribution of the basin-scale unconformity structure.

[0017] Step S4 is: according to the drilling, logging, reflection seismic and other data, through the interpretation of the tecto-stratigraphic units in the deep buried area, identifying the main faults, using the balanced section method to qualitatively and semi-quantitatively determine the fault tectonic activity and effect in different periods; combining the gravity, magnetic, electrical and other geophysical data, identifying the magmatic rock records existing in the tecto-stratigraphic units, and clarifying the possible magmatic events, superimposing the results of step S4 on the unconformity structure distribution map of the main tectonic movement, to obtain the paleostructure-paleogeomorphology map in different periods.

[0018] Step S5 is: using the synthetic record and velocity analysis to finely calibrate the seismic reflection interface, analyzing the seismic reflection characteristics of each tecto-stratigraphic unit in the deep buried area, and drawing the planar distribution map of the seismic reflection structure and the reflection amplitude, frequency, continuity and other multi-attribute characteristics. Through seismic wavelet extraction, low-frequency model establishment, and multi-time window layered wave impedance inversion, the wave impedance profile of each tecto-stratigraphic unit obtained by constrained sparse pulse inversion is obtained, and it is converted into tecto-sedimentary section according to S1, S2 and S3.

[0019] Step S6 is: on the basis of the paleostructure-paleogeomorphology map in different periods, combining the seismic attributes and wave impedance profile of the tecto-stratigraphic units according to the drilling and sedimentary facies model, forming the spatial distribution of the sedimentary facies belts controlled by paleostructure. According to the tectonic activity of the basin edge and deep part in different periods, the basin-scale tectonic paleogeography in each single tectonic movement period is restored.

[0020] Compared with the prior art, the present application makes full use of outcrop data, drilling, logging and various geophysical data, carries out comprehensive geology and geophysics analysis, restores the structure and paleogeography of deep buried area by using the basin structure and geophysical multi-attribute of different periods, and provides scientific, reliable and high-precision evidence for the cognition and resource exploration of deep and super-deep layers under the double conditions of mutual constraint of paleostructure and paleogeography. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the method of the present application.

[0022] Figure 2a The figure is a process diagram for establishing the paleostructure-sedimentary section of the embodiment of the present application, and is a Cambrian bottom reflection layer layer-pulled section diagram of the section AA' in the southeast Tarim Basin;

[0023] The unconformity structure characteristics and types are annotated, and the seismostriagraphy characteristics are also marked in the section, wherein H, M and L represent high, medium and low respectively, and A, F, C and I represent the seismic reflection wave amplitude, frequency, continuity and wave impedance of the single structure-stratigraphic unit respectively;

[0024] Figure 2b The figure is a sparse pulse wave impedance inversion section diagram of the section AA' of the embodiment of the present application.

[0025] Figure 2c The figure is a structure-sedimentary section diagram obtained by the comprehensive analysis of the sequence stratigraphic framework, sedimentary facies and b, c of the embodiment of the present application, and the section position is shown in Figure 3 .

[0026] Figure 3 The figure is a spatial distribution diagram of the unconformity structure and seismic attribute in the single structure-stratigraphic unit of the deep buried area, and is a schematic diagram of the planar distribution of the unconformity structure and the seismic stratigraphic multi-attribute characteristics of the Nanhua System and the Sinian System in the Tarim Basin.

[0027] Figure 4 The figure is a restored structure paleogeography diagram under the single structure movement of the deep buried area, and is a schematic diagram of the pre-Sinian structure paleogeography in the Tarim Basin. ①-⑩ are the obtained magmatic event ages. DETAILED DESCRIPTION

[0028] The present application will be further described in combination with the drawings.

[0029] Referring to Figures 1-4 , the present application discloses a method for reconstructing the structure-polyattribute paleogeography of the deep buried area of a superimposed basin, which comprises the following steps:

[0030] S1, establishing the outcrop area and drilling stratigraphic sequence framework and sedimentary facies model;

[0031] S2, determining the vertical structure-stratigraphic unit of the deep buried area of the superimposed basin;

[0032] S3, determining the spatial distribution of the unconformity structure of the deep buried area under single tectonic movement;

[0033] S4, determining the main paleo-active faults and magmatic activities in the deep buried area;

[0034] S5, identifying and determining the spatial distribution of the seismic stratigraphic characteristics and seismic attributes in the single tectonic-stratigraphic unit;

[0035] S6, reconstructing the tectonic paleogeography under single tectonic movement of the superimposed basin according to S3, S4 and S5.

[0036] Step S1: According to the field geological survey of the outcrop profile of the basin edge, identify and clarify the regional unconformity and local unconformity, take the regional unconformity as the boundary of the stratigraphic sequence framework, analyze the petrological and sedimentological characteristics of the stratigraphic sequence, and establish the sedimentary facies model.

[0037] Step S2: Comparing the stratigraphic sequence development characteristics of the outcrop area, combining with the comprehensive analysis of the drilling, logging and seismic data in the basin, establishing the stratigraphic sequence framework that can be compared in the outcrop area and downhole; determining the tectonic-stratigraphic unit in the deep buried area according to the main tectonic movement period.

[0038] Step S3: According to the tectonic-stratigraphic unit division scheme of the deep buried area, using drilling, logging and seismic data, making synthetic seismograms, determining each tectonic-stratigraphic unit on the cross-well section, and expanding the identification and interpretation of each tectonic-stratigraphic unit in the deep buried area, dissecting the unconformity structure of the main tectonic-stratigraphic unit, including systematic analysis of the tectonic deformation of the underlying strata of the unconformity, the planar distribution of the unconformity structure type, the sedimentary structure of the overlying strata and the initial sediments and their sources, etc.; using the layer flattening method, qualitatively and semi-quantitatively identifying and analyzing the main unconformity structure types and deformation characteristics in the deep buried area (such as Figure 2a ), marking them on the plan view according to different tectonic-stratigraphic units, and determining the spatial distribution of the basin-scale unconformity structure.

[0039] Step S4: According to the drilling, logging, reflection seismic and other data, through the interpretation of the tectonic-stratigraphic unit in the deep buried area, identifying the main faults, using the balanced section method to qualitatively and semi-quantitatively determine the fault tectonic activity and effect of different periods; combining with gravity, magnetic, electrical and other geophysical data, identifying the magmatic rock records existing in the tectonic-stratigraphic unit, clarifying the possible magmatic events, superimposing the results of step S4 on the unconformity structure distribution map of different tectonic movements, and obtaining the paleo-tectonic-paleogeomorphology map of different periods.

[0040] Step S5 is: using synthetic recording and velocity analysis fine calibration seismic reflection interface, the seismic reflection characteristics of each structure-stratigraphic unit in the deep buried area are analyzed, and the planar distribution map of seismic reflection structure and reflection amplitude, frequency, continuity and other multi-attribute characteristics (such as Figure 3 ) is drawn; through seismic wavelet extraction, low frequency model establishment, multi-time window layered wave impedance inversion, the wave impedance profile of each structure-stratigraphic unit obtained by constrained sparse pulse inversion (such as Figure 2b ) is obtained, and it is converted into a structure-sedimentary profile (such as Figure 2c ) according to S1, S2 and S3.

[0041] Step S6 is: on the basis of paleostructure-paleogeomorphology maps in different periods, according to drilling and sedimentary facies model, the seismic attributes and wave impedance profile of the structure-stratigraphic unit are combined to form a spatial distribution of sedimentary facies belts controlled by paleostructure. According to the tectonic activity of the basin edge and deep part in different periods, the basin-scale tectonic paleogeography in each single tectonic movement period is restored (such as Figure 4 ).

[0042] The above is only the preferred embodiment of the present application, which is only used to help understand the method and its core idea of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments, and any technical solution belonging to the idea of the present application shall belong to the protection scope of the present application. It should be noted that for ordinary skilled persons in the technical field, some improvements and decorations without departing from the principle of the present application shall also be considered as the protection scope of the present application.

[0043] The present application solves the problems in the prior art that due to the difference in drilling distribution density, it is difficult to form high-quality paleogeographic maps in the area where no drilling is revealed, especially lacking the control of contemporaneous tectonic action. For the deep buried area of the superimposed basin, due to unclear distribution of the prototype basin and uncertain preservation of the residual basin, combined with very few drilling data, the paleogeographic map is mostly in medium and small scales, causing that most regions are almost speculated and extended without data and material support, and it is difficult to provide scientific, direct and practical evidence for deep resource evaluation. Through fully utilizing outcrop data, drilling and logging and various geophysical data, comprehensively analyzing geology and geophysics, using basin structures and geophysical multi-attributes in different periods, the tectonic paleogeography of the deep buried area is restored, and from the double conditions of mutual constraint of paleostructure and paleogeography, scientific, reliable and high-precision evidence is provided for cognition and resource exploration of deep and ultra-deep layers.

Claims

1. A method for structure-multiple attribute palaeogeographic reconstruction of deep buried area in a superimposed basin, characterized in that, The method comprises the following steps: S1, establishing outcrop area and drilling stratum sequence framework and sedimentary facies model; S2, determining vertical structure-stratum unit in deep buried area of superimposed basin; S3, determining spatial distribution of unconformity structure under single tectonic movement in deep buried area; S4, determining main ancient active faults and magmatic activity in deep buried area; S5, identifying and determining spatial distribution of seismic stratigraphic characteristics and seismic attribute in single structure-stratum unit; S6, reconstructing tectonic palaeogeography under single tectonic movement of superimposed basin according to S3, S4 and S5. The step S3 is: according to structure-stratum unit division scheme of deep buried area, using drilling, logging and seismic data, making composite seismic record, determining each structure-stratum unit on well profile, and unfolding identification and interpretation of each structure-stratum unit in deep buried area, dissecting main unconformity ternary structure, including systematic analysis of structure deformation of underlying stratum of unconformity, plane distribution of unconformity structure type, sedimentary structure and initial sediments and their sources of overlying stratum of unconformity; adopting layer flattening method to qualitatively and semi-quantitatively further identify and analyze main unconformity structure type and deformation characteristics in deep buried area, respectively marking on plane graph, and determining spatial distribution of each unconformity structure in basin scale. The step S4 is: according to drilling, logging and reflection seismic data, identifying main faults through interpretation of structure-stratum unit in deep buried area, qualitatively and semi-quantitatively determining fault tectonic activity and effect in different periods by adopting balanced section method, combining gravity, magnetic and electrical geophysical data, identifying magmatic rock record in structure-stratum unit, and determining possible magmatic event, superimposing results of step S4 on unconformity structure distribution graph of each main tectonic movement, and obtaining palaeostructure-palaeogeomorphology graph in different periods. The step S5 is: using composite record and velocity analysis to finely mark seismic reflection layer interface, analyzing seismic reflection characteristics of each structure-stratum unit in deep buried area, drawing plane distribution graph of seismic reflection structure and reflection amplitude, frequency and continuity multi-attribute characteristics, extracting seismic wavelet, establishing low frequency model, and performing multi-time window layered wave impedance inversion, obtaining wave impedance profile of each structure-stratum unit obtained by constrained sparse pulse inversion, and converting it into structure-sedimentary profile according to S1, S2 and S3.

2. The method of multi-attribute structural palaeogeographic reconstruction of the deep-buried zone of the superimposed basin according to claim 1, characterized in that, The step S1 is: according to field geological survey of basin edge outcrop profile, identifying and determining existing regional unconformity and local unconformity, taking regional unconformity as division of stratum sequence framework, analyzing petrology and sedimentology characteristics of stratum sequence, and establishing sedimentary facies model.

3. The method of claim 1, wherein the method is a method of multi-attribute structural palaeogeographic reconstruction of a deep-burial zone structure of a superimposed basin, characterized in that, The step S2 is: comparing stratum sequence development characteristics of outcrop area, combining comprehensive analysis of drilling, logging and seismic data in basin, establishing stratum sequence framework of outcrop area and downhole comparable stratum sequence; and determining structure-stratum unit in deep buried area according to main tectonic movement period.

4. The method of claim 1, wherein the method is a method of multi-attribute structural palaeogeographic reconstruction of a deep-burial zone structure of a superimposed basin. The step S6 is: on the basis of the paleostructure-paleogeomorphology maps of different periods, combining the seismic attributes of the structural stratigraphic units with the wave impedance profiles according to the drilling and the sedimentary facies model, the spatial distribution of the sedimentary facies belts controlled by the paleostructure is formed; according to the tectonic activities of the basin edges and the deep parts in different periods, the basin-scale tectonic palaeogeography of each single tectonic movement period is restored.

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