Sedimentary facies prediction system based on seismic amplitude attribute proportion analysis on level

Abstract

The invention discloses a sedimentary facies prediction system based on seismic amplitude attribute proportion analysis on a level, and relates to the technical field of petroleum geological exploration. Comprising a module for establishing a geologic mathematical model by utilizing modern deposition, a well-seismic data calibration association module, a well point stratum sand-to-ground ratio and sedimentary facies interpretation fitting module, a seismic amplitude parameter algorithm selection module, a seismic amplitude root-mean-square data statistical analysis module and a module for dividing value domain intervals of sedimentary facies in the vertical direction and the plane. The system comprises a seismic amplitude RMS model, a modern sedimentary geologic model and seismic amplitude layer plane proportion fitting module, a sedimentary facies color plate distribution module and a seismic amplitude root-mean-square attribute sedimentary facies display module, and a sedimentary facies plane relation established by modern sedimentary is applied to a statistical result of a numerical value plane analysis proportion of the seismic amplitude RMS. And speculating the distribution of the sedimentary facies on the layer according to the proportion of the accumulated area of each seismic amplitude RMS value, thereby realizing the spatial distribution prediction of the sedimentary facies on the vertical dimension and the layer dimension.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum geological exploration, and in particular to a sedimentary phase prediction system based on analysis of seismic amplitude attribute proportions at a layer. Background Art

[0002] Sedimentary facies research is an important branch of geology and sedimentology. It classifies and interprets strata based on the formation environment, formation conditions and characteristics of sediments. Through the study of modern sedimentary facies, the past sedimentary environment and geological history can be inferred, providing useful information for resource exploration, seismic exploration, marine engineering and other fields.

[0003] In terms of spatial distribution, vertically continuous sediments overlap each other without interruption. Sedimentary phase sequences can also be seen horizontally, and this can be used to infer the type and series of sedimentary phases in adjacent areas. The analysis of sedimentary phases uses the method of using the present to discuss the past. Inferring the past sedimentary environment with modern sedimentary patterns is the main means of sedimentary phase research at present. In practical applications, it is usually through analyzing the relationship between actual drilling sedimentary phases and sand-to-ground ratios, establishing the relationship between regional sedimentary phases and sand-to-ground ratios, and thus inferring the distribution of the corresponding sedimentary phases on the plane.

[0004] With the widespread use of satellite color imaging technology in modern sedimentary facies research, we can have a clearer understanding of the changing laws of sedimentary facies in different periods from a macro perspective. Taking the Poyang Lake Delta as an example, a large amount of data and image data on the changes in the area of ​​lakes and deltas in different periods have been accumulated. Through the study of the change rate of sedimentary area of ​​different sedimentary units, the changing laws of modern sedimentary facies on the plane can be established. These can provide a reliable theoretical basis for using modern sedimentary models to reveal the sedimentary laws that occurred in the past geological history.

[0005] It is an important physical method to reveal the distribution of sedimentary systems in three-dimensional space by analyzing the characteristics of seismic phases. Seismic phases are the seismic responses of specific sedimentary phases or geological bodies on three-dimensional seismic bodies, that is, the comprehensive reflection of the spatial combination of sedimentary body shapes, rock layer superposition patterns, and lithological differences. The geological interpretation of seismic parameters contained in seismic phases (such as reflection structure, continuity, external geometry, amplitude, frequency, layer velocity, etc.) can infer the distribution of different sedimentary bodies on the plane. The distribution law on the plane should also be similar to that of modern sediments, and modern sedimentary models can be applied to the analysis and research of ancient sedimentary phases.

[0006] The statistical data of sand-to-formation ratio in single-well sedimentary facies analysis is an important quantitative indicator for dividing sedimentary facies. By matching the sand-to-formation ratio obtained from drilling statistics with the results of single-well sedimentary facies analysis and combining them with regional data, the sand-to-formation ratio sedimentary facies division standard suitable for this block can be determined.

[0007] At present, the method of sand-to-formation ratio and the distribution of seismic attributes on the plane as a constraint is widely used in drawing sedimentary facies planar distribution maps. Due to the differences in the value ranges of sedimentary facies and sand-to-formation ratios in different regions, there is no unified division standard; secondly, when using seismic attribute data to predict the planar distribution of sedimentary facies, the sand-to-formation ratio of the well point is usually fitted with the seismic attribute value to determine the range of seismic attribute values ​​of the sedimentary facies to which the corresponding sand-to-formation ratio belongs, and this is used as the standard to divide the sedimentary facies on the plane. This method assumes that the sedimentary facies determined by the sand-to-formation ratio in the vertical direction is its distribution on the layer or plane.

[0008] The spatial distribution of sedimentary facies can be described as follows: sedimentary facies that change continuously in the vertical direction can also be observed continuously in the horizontal direction, and the corresponding description of the observed object is from the two dimensions of vertical and horizontal. From the perspective of geological sedimentology, the sedimentary facies determined by the sand-to-formation ratio in the vertical direction is not a simple mapping of it on the plane. The sedimentary facies is the spatial distribution of similar rocks with the same sedimentary environment and formation conditions. It reflects the vertical distribution of sedimentary facies determined by the sand-to-formation ratio range on the plane, that is, the spatial distribution proportion of the point set formed by each point on the plane. At present, in the analysis of sedimentary facies, the relationship between the vertical sand-to-formation ratio and sedimentary facies is usually used to infer the distribution of sedimentary facies on the plane, without considering the relationship between the change of the sand-to-formation ratio of each point in the vertical direction and its corresponding proportion on the plane. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a method for predicting the spatial distribution of sedimentary phases based on the analysis of the proportion of seismic amplitude attributes in two dimensions, vertical and horizontal.

[0010] In order to solve the above technical problems, the present invention provides a sedimentary facies prediction system based on the analysis of seismic amplitude attribute proportions at the layer, comprising: According to the distribution ratio of sedimentary phases observed in modern sedimentation, mathematical methods are selected to establish a mathematical geological model that conforms to the phase sequence change law, forming a prediction module for the plane distribution of ancient sedimentary phases based on modern sedimentary patterns; Well-seismic data calibration and association module, which produces seismic synthetic records based on drilling and seismic data, calibrates the studied layer section on the seismic section, and establishes the correspondence between drilling data and seismic data; Well-point formation sand-to-formation ratio and sedimentary facies interpretation fitting module determines the threshold value of the Vshl mud content parameter in the study area, uses the same threshold value to count the sand-to-formation ratio of each layer in different well sections, fits the sand-to-formation ratio with the interpreted sedimentary facies, and obtains the relationship between the sand-to-formation ratio and the continuous sedimentary facies; The seismic amplitude parameter algorithm selection module determines the seismic amplitude root mean square RMS algorithm as the data source reflecting the distribution law of sedimentary phases on the plane through analysis and comparison of the results of multiple algorithms.

[0011] The seismic amplitude root mean square RMS data acquisition module extracts the seismic amplitude RMS value along the seismic interpretation plane or between layers to obtain the seismic amplitude RMS value cumulative proportion curve; The module for fitting the modern sedimentary geological model and the RMS proportion of seismic amplitude in the plane is based on the mathematical geological model established by modern sedimentation, and is fitted with the curve of the cumulative proportion of the RMS plane of seismic amplitude to obtain the relationship between the proportion of the RMS plane of seismic amplitude and the continuous sedimentary phase; The module for dividing the value range of sedimentary phases in the vertical and horizontal planes obtains the relationship between the sand-to-formation ratio and the proportion of continuous sedimentary phases in the plane according to the relationship between the cumulative proportion of the seismic amplitude RMS plane and the continuous sedimentary phases, combined with the relationship between the sand-to-formation ratio and the continuous sedimentary phases, thereby determining the value range of the sand-to-formation ratio and the seismic amplitude RMS value for dividing the sedimentary phases in the vertical and horizontal planes of the continuous sedimentary phase sequence.

[0012] According to a preferred embodiment of the present invention, the sedimentary phase prediction system also includes a sedimentary phase color plate allocation module, which specifies colors for the seismic amplitude RMS value ranges corresponding to different deposits on the seismic amplitude RMS numerical analysis diagram, forming a sedimentary phase color plate that can both distinguish different sedimentary phases and present sedimentary characteristics.

[0013] According to a preferred embodiment of the present invention, the sedimentary phase prediction system also includes a seismic amplitude root mean square attribute sedimentary phase display module, which applies a sedimentary phase color plate to the acquired seismic amplitude RMS data and presents the distribution range of each sedimentary phase in different colors on the plane.

[0014] According to a preferred embodiment of the present invention, the module for establishing a geological mathematical model using modern sedimentation also performs statistical analysis based on changes in geological area to verify the relationship between sedimentary phases and the rate of change of geological area.

[0015] According to a preferred embodiment of the present invention, in the well-seismic data calibration association module, the drilling and seismic data are well acoustic waves, density data and seismic VSP data.

[0016] According to a preferred embodiment of the present invention, in the well point formation sand-to-formation ratio and sedimentary phase interpretation fitting module, the Vshl parameter threshold value of the study area is determined to be the optimal value of the correlation after the actual drilling logging curve of the study area is standardized.

[0017] According to a preferred embodiment of the present invention, in the seismic amplitude parameter algorithm selection module, the analysis is a correlation analysis of calculation results of different algorithms for commonly used seismic amplitude parameters.

[0018] According to a preferred embodiment of the present invention, in the seismic amplitude root mean square (RMS) data acquisition module, seismic amplitude RMS values ​​are counted at equal intervals.

[0019] According to a preferred embodiment of the present invention, in the modern sedimentary geological model and the layer seismic amplitude RMS proportion fitting module, the power exponent value of the fitting curve is adjusted to make the sedimentary phase area proportion and sedimentation relationship between modern sediments and ancient sediments match.

[0020] The technical effects of the present invention are: 1. The present invention provides a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the plane. By analyzing the distribution proportion of sedimentary phases or subphases of modern sediments on the plane, the distribution law of each sedimentary phase sequence on the plane is found, a mathematical geological model is established, and the distribution of the sedimentary phase sequence on the plane or plane is inferred based on the analysis of the seismic phase. The seismic phase includes various seismic parameters that reflect sedimentary information. The proportion of these seismic attribute parameters that can characterize the sedimentary phase information on the plane and the proportion of each sedimentary phase sequence of modern sedimentation are compared with the sedimentary phase observed in modern deposition and the change relationship of its area proportion, thereby establishing two different but mutually self-consistent sedimentary phase division interval standards based on sand-to-ground ratio and sedimentary area proportion in the vertical and planar dimensions, and realizing the prediction of the spatial distribution of sedimentary phases in the vertical and planar dimensions based on the analysis of seismic amplitude attribute proportion.

[0021] 2. The present invention provides a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes in the layer. The seismic amplitude root mean square (RMS) that can reflect the rock phase change is selected as the characteristic seismic phase parameter for sedimentary phase prediction. Compared with the minimum seismic amplitude sum algorithm, the seismic amplitude RMS has a higher correlation with the sand-to-land ratio, which can better reflect the geological sedimentological significance contained in its algorithm design.

[0022] 3. The present invention provides a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes in the layer. Based on the seismic amplitude value range corresponding to the proportion of different sedimentary phase areas on the seismic amplitude RMS numerical statistical histogram, a unified seismic amplitude attribute sedimentary phase color plate is compiled, so that the sedimentary significance represented by the sedimentary phase color plate can be traced.

[0023] 4. The present invention provides a sedimentary facies prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer level. The seismic amplitude attribute RMS numerical statistical analysis results are combined with the actual drilling sedimentary facies, and the seismic amplitude RMS value range corresponding to different sedimentary subfacies and microfacies is determined by referring to the regional sand-to-land ratio sedimentary facies demarcation standard, thereby forming a quantitative seismic sedimentary facies prediction model based on data statistical results.

[0024] 5. The present invention provides a sedimentary facies prediction system based on the analysis of the proportion of seismic amplitude attributes at the level. In the seismic amplitude RMS numerical statistical histogram, the sedimentary subfacies and sedimentary microfacies (secondary and tertiary sedimentary units) are determined by a unified sedimentary facies division standard, thereby making the concept of using seismic amplitude attributes to predict sedimentary facies more perfect and the hierarchy more complete.

[0025] 6. The present invention provides a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer level. By using data statistical methods, the threshold value for dividing sedimentary phases using the root mean square (RMS) of seismic amplitude is determined at both the layer level (macro) and the well point (micro) scales, thereby providing a more reasonable geological sedimentary interpretation of the lithofacies information contained in the seismic amplitude attributes from point to surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a sedimentary pattern diagram of lake basin river delta in a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer in the present invention; Figure 2 It is a geological complex function coordinate system relationship diagram of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer in the present invention; Figure 3 It is a relationship diagram between the accumulated amount of horizontal sedimentary phase components and the accumulated amount of vertical sedimentary phase components of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer surface of the present invention; Figure 4 It is a curve diagram of the relationship between the sedimentary phase or subphase and the area occupied by the sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer in the present invention; Figure 5 It is a relationship diagram between sedimentary phase sequence and sand-to-ground ratio of a sedimentary phase prediction system based on the analysis of seismic amplitude attribute proportion on the layer surface of the present invention; Figure 6 It is a water area distribution map of the main body of Poyang Lake and nearby waters from 2011 to June-August 2020 in a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer in the present invention; Figure 7 It is a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer, and a fitted diagram of the transformation of the water area of ​​Poyang Lake and nearby waters from 2013 to July 2020; Figure 8 It is a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer, and a map of the expansion rate of the water area of ​​Poyang Lake from 2013 to July 2020; Fig. 9It is a map of the area change of the front edge of the Ganjiang River Delta in Poyang Lake observed every 11 years from 1973 to November-December 2006 by a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer according to the present invention; Fig.10 It is a fitting diagram of the area change of the Poyang Lake and Ganjiang River Delta from 1973 to December 2006 based on the sedimentary phase prediction system of the present invention based on the analysis of the proportion of seismic amplitude attributes on the layer; Fig.11 It is a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer, and the area expansion rate map of the Poyang Lake Ganjiang River Delta from 1973 to December 2006; Fig.12 It is a fitting diagram of lake area change rate and triangle area expansion rate of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer in the present invention; Fig.13 The present invention is a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the plane, which is a planar distribution and proportion map of each sedimentary phase in the Ganjiang Delta; Fig.14 It is a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer, and a fitting diagram of the proportion of the sedimentary phase area distribution of the modern delta of Poyang Lake; Fig.15 It is a well-seismic calibration result diagram of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer in the present invention; Fig.16 It is a relationship diagram between T70-T71 threshold value cutoff cumulative thickness and layer thickness of a sedimentary phase prediction system based on the analysis of seismic amplitude attribute proportion on the layer surface of the present invention; Fig.17 It is a relationship diagram between the cumulative thickness and layer thickness of the sedimentary phase prediction system T70-EP210 threshold value cutoff based on the analysis of the proportion of seismic amplitude attributes on the layer in the present invention; Fig.18 It is a diagram of the seismic amplitude RMS value at the Enping 1 (T70-T71) well point of the sedimentary phase prediction system based on the analysis of the seismic amplitude attribute ratio at the layer in the present invention; Fig.19 It is a seismic amplitude RMS value diagram at the well point of Enping II (T71-EP210) of the sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer of the present invention; Fig. 20 It is a fitting diagram of the actual drilling sand-to-ground ratio and seismic amplitude RMS of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer in the present invention; Fig.21It is a fitting diagram of the sand-to-ground ratio and amplitude RMS of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer in the present invention; Fig. 22 It is a fitting diagram of the cumulative proportion of the plane distribution of the seismic amplitude RMS value of the sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer in the present invention; Fig.23 It is a sedimentary phase prediction system EP1 (T70-T71) seismic amplitude RMS numerical distribution diagram based on the analysis of seismic amplitude attribute proportion on the layer of the present invention; Fig.24 It is a seismic amplitude RMS numerical distribution diagram of the sedimentary phase prediction system EP2 (T70-EP210) based on the analysis of the seismic amplitude attribute ratio on the layer in the present invention; Fig.25 It is a superimposed diagram of the relationship between the cumulative proportion of the plane distribution of the seismic amplitude RMS value and the proportion of the area of ​​the modern sedimentary phase in a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the plane. Fig.26 It is a fitting relationship diagram between continuous sedimentary phase sequence and block seismic amplitude RMS of a sedimentary phase prediction system based on the analysis of seismic amplitude attribute proportion at the layer in the present invention; Fig. 27 It is a fitting relationship diagram of continuous sedimentary phase sequence and sand-to-ground ratio of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer in the present invention; Fig.28 It is a fitting relationship diagram of continuous sedimentary phase sequence and sedimentary phase plane proportion of a sedimentary phase prediction system based on the analysis of seismic amplitude attribute proportion on the layer in the present invention; Fig.29 It is a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer, and is a real drilling sand-to-ground ratio and sedimentary subphase division diagram of the present invention; Fig.30 It is a sedimentary phase prediction system T70-T71 seismic amplitude RMS value distribution histogram based on the analysis of seismic amplitude attribute proportion at the layer in the present invention; Fig.31 It is a sedimentary phase prediction system T71-EP210 based on the analysis of the proportion of seismic amplitude attributes on the layer of the present invention) seismic amplitude RMS value distribution histogram; Fig.32 The present invention provides a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer and a numerical interval distribution statistic and sedimentary phase diagram; Fig.33 It is a sedimentary phase color plate diagram of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes on the layer according to the present invention; Fig.34It is a sedimentary phase distribution prediction map of a sedimentary phase prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer according to the present invention; Fig.35 It is a flow chart of seismic amplitude RMS sedimentary phase distribution prediction of a sedimentary phase prediction system based on analysis of seismic amplitude attribute proportion at the layer level of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the invention.

[0029] like Figures 1 to 35 As shown, a sedimentary facies prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer, comprising: According to the distribution ratio of sedimentary phases observed in modern sedimentation, mathematical methods are selected to establish a mathematical geological model that conforms to the phase sequence change law, forming a prediction module for the plane distribution of ancient sedimentary phases based on modern sedimentary patterns; Well-seismic data calibration and association module, which produces seismic synthetic records based on drilling and seismic data, calibrates the studied layer section on the seismic section, and establishes the correspondence between drilling data and seismic data; Well-point formation sand-to-formation ratio and sedimentary facies interpretation fitting module determines the threshold value of the Vshl mud content parameter in the study area, uses the same threshold value to count the sand-to-formation ratio of each layer in different well sections, fits the sand-to-formation ratio with the interpreted sedimentary facies, and obtains the relationship between the sand-to-formation ratio and the continuous sedimentary facies; The seismic amplitude parameter algorithm selection module determines the seismic amplitude root mean square RMS algorithm as the data source reflecting the distribution law of sedimentary phases on the plane through analysis and comparison of the results of multiple algorithms.

[0030] The seismic amplitude root mean square RMS data acquisition module extracts the seismic amplitude RMS value along the seismic interpretation plane or between layers to obtain the seismic amplitude RMS value cumulative proportion curve; The module for fitting the modern sedimentary geological model and the RMS proportion of seismic amplitude in the plane is based on the mathematical geological model established by modern sedimentation, and is fitted with the curve of the cumulative proportion of the RMS plane of seismic amplitude to obtain the relationship between the proportion of the RMS plane of seismic amplitude and the continuous sedimentary phase; The module for dividing the value range of sedimentary phases in the vertical and horizontal planes obtains the relationship between the sand-to-formation ratio and the proportion of continuous sedimentary phases in the plane according to the relationship between the cumulative proportion of the seismic amplitude RMS plane and the continuous sedimentary phases, combined with the relationship between the sand-to-formation ratio and the continuous sedimentary phases, thereby determining the value range of the sand-to-formation ratio and the seismic amplitude RMS value for dividing the sedimentary phases in the vertical and horizontal planes of the continuous sedimentary phase sequence.

[0031] The key to giving a reasonable explanation for the distribution of sedimentary facies on the plane lies in how to use the method of inferring the past from the present to apply the sedimentary facies change laws observed today to the speculation of the ancient sedimentary facies distribution. To solve this geological problem, we can start from the following two aspects: First, by analyzing the distribution proportion of modern sedimentary facies or subfacies on the plane, we can find out the distribution law of each sedimentary facies sequence on the plane and establish a mathematical geological model; second, we can identify various data representing sedimentary facies information obtained from a depth of thousands of meters underground, find out the parameters with the best correlation with the sedimentary facies, establish the correlation between contemporary and ancient sedimentary facies through statistical analysis of the data, and apply the mathematical model based on modern sedimentation to the analysis and research of ancient sedimentary facies, so as to speculate the spatial distribution of sedimentary facies in both vertical and horizontal dimensions. For ancient deposits buried thousands of meters underground, the distribution of sedimentary phase sequences on the layer (or plane) can be inferred through the analysis of seismic phases. Seismic phases contain various seismic parameters that reflect sedimentary information. The proportion of these seismic attribute parameters that can characterize sedimentary phase information on the layer (or plane) should also be similar to the proportion of each sedimentary phase sequence in modern sediments. By analogy with the relationship between the sedimentary phases observed in modern sediments and their area proportion changes, a reasonable explanation can be given to ancient deposits from the perspective of modern sediments, and two different but self-consistent sedimentary phase division interval standards based on sand-to-ground ratio and sedimentary area proportion can be established in both vertical and planar dimensions. In order to verify the correctness of the mathematical model established by geological concepts, the area change rate data of the shore, shallow lake and front delta of the modern sedimentary Poyang Lake in the past 10-40 years were selected to examine the correlation between the modern sedimentary facies and its area change rate on the plane; for ancient sediments, the Enping stratum of the Paleogene Eocene in the Pearl River Mouth Basin was taken as the research target, the seismic amplitude attributes of En1 and En2 segments were extracted and the statistical analysis of the area distribution was performed, the numerical distribution of the area of ​​ancient and modern sedimentary facies was compared, and the division interval of the sand-to-land ratio of the plane sedimentary facies was determined, forming a prediction method for ancient sedimentary facies based on the modern sedimentary model and the plane ratio analysis results of seismic amplitude attributes.

[0032] Specifically, modern sediments are used to establish a geological mathematical model: by statistically analyzing the changes in the lake area and the area of ​​the front delta of Poyang Lake taken by meteorological satellites over the past 10-40 years, the relationship between sedimentary phases and area change rates is verified, and the observed geological phenomena are fitted with mathematical formulas to establish a mathematical geological model; First, the spatial distribution of the sedimentary phase sequence is described as follows: The spatial distribution of the sedimentary phase sequence is described as follows: the phases with similar genesis and closely adjacent development in the horizontal direction appear in succession without interruption in the vertical direction. Based on the phase sequence transition law: the phases and phase areas that appear successively on the same sedimentary interface at the same period in the sedimentary process overlap vertically and change successively, such as Figure 1The lake basin river delta sedimentary model shown in the figure; the phase sequence law reflects that the distribution of the sedimentary phase sequence on the isochronous sedimentary interface is closely related to its vertical superposition. If the change of the phase sequence on the sedimentary interface is expressed by the horizontal and vertical sedimentary phase components respectively, this geological concept is converted into the following mathematical model: like Figure 2 As shown in the figure, let the real axis x be the distribution of continuous sedimentary phase (or sub-phase) on the horizontal component, the y axis be the distribution of continuous sedimentary phase (or sub-phase) on the vertical component, the z axis be the distribution of sedimentary phase (or sub-phase) on the plane, and the sedimentary phase (or sub-phase) be limited by the range of sand-to-ground ratio. The geological problem can be expressed by the following complex variable function:

[0033] The real and imaginary parts of a complex number form a two-dimensional rectangular coordinate system. According to the relationship between the rectangular coordinate system and the polar coordinate system, it can be expressed as follows: Figure 2 As shown:

[0034] According to Euler's formula: , transformed into the exponential form of a complex number: .in is called the modulus of a complex number and is denoted by ; is called the argument of the complex number and is denoted by .

[0035] We only consider the cumulative amount of each sedimentary phase on the layer, ignoring its rotation on the complex plane, and the model can be simplified as , and converted into the relationship between the sedimentary phase or subphase and its layer area ratio, as shown in 3.

[0036] x and y are the horizontal and vertical components of the sedimentary facies (or subfacies), respectively. To define the minimum and maximum interval values ​​of the sedimentary phase (or subphase); the amplitude angle φ is between 0 and 1.8. Since the sedimentary phase (or subphase) in the sedimentary phase sequence is determined by the range of the sand-to-ground ratio, this formula is converted into the relationship between the sedimentary phase (or subphase) and the sand-to-ground ratio in the continuous sedimentary phase sequence.

[0037] According to е The exponential property of the base is that the value of a point on the curve is the area occupied by the line at that point, that is, the area occupied by any sedimentary phase sequence φ on the layer (plane) is the area occupied by the curve at that point. , the area proportion of the sedimentary phase (or subphase) can be inferred by calculation according to the formula, such as Figure 4 described.

[0038] The sand-to-ground ratio is a key parameter for vertically dividing each sedimentary facies or sub-facies. For a specific sedimentary facies (or sub-facies) in a continuous sedimentary sequence, as sedimentary layers are continuously superimposed, when the cumulative sand-to-ground ratio gradually approaches within its set threshold range, it is considered that the sedimentary sub-facies has changed. Thus, the geological concept is transformed into the following mathematical model. As Figure 5 shown, the sand-to-ground ratio shows a gradually increasing trend with the change of sedimentary facies sequence.

[0039] In a continuous sedimentary facies sequence formed by different sedimentary cycles, if each sedimentary facies or sub-facies can be distinguished by a series of interval values of sand-to-ground ratio 0 < a < b < c < d < e < 1 in this way, for any sedimentary facies or sub-facies, if n sedimentary cycles occur cumulatively within the interval value of sand-to-ground ratio 0 < a < b, then its ultimately cumulative maximum sand-to-ground ratio has an extreme value and approaches the constant e; here, it is only necessary to prove 0 < a < b, and the rest are the same. The following is the mathematical proof process: First step, we prove an inequality. For any real numbers a and b that satisfy b > a > 0, the inequality holds. This is because , and since a < b, so replacing all a in the second bracket of the above formula with b will surely make the result larger, thus the inequality to be proved holds. Then, this inequality is rearranged as ; Second step, let the integer n > 1, and let , , at this time, the prerequisite condition of b > a > 0 is still satisfied, then formula (2) still holds. Substituting it into formula (2), we get , which shows that increases monotonically with n; Third step, let , , substituting it into formula (2), we get , squaring both sides, we get , because n is any integer greater than 1, which shows that this sequence has an upper bound. A monotonically increasing sequence with an upper bound must have a limit. is transformed into . This shows that the interval value of the cumulative sand-to-ground ratio corresponding to the vertical division of sedimentary facies or sub-facies has an extreme value and approaches the natural constant e.

[0040] Finally, in order to verify the feasibility of the mathematical model, the modern sediment of Poyang Lake is selected as a sample to reveal ancient sedimentation. Figure 6This is the distribution map of the water area of ​​the main body of Poyang Lake and nearby waters from June to August 2011 to 2020; the data measured in 2011-2012 were not listed in the statistical table because they were measured in June and August, respectively, which deviated from the observation time in July in other years; in order to reduce the impact of short-term fluctuations in lake area on the overall change trend, the lake areas observed in the past 9 years are ranked from small to large, and the corresponding sedimentary phase sequence is assigned at intervals of 0.02 starting from 0.30, as shown in Table 1 below:

[0041] Table 1 Figure 7 and Figure 8 As a result of fitting these data, the fitting formula shows that the change in lake area can be expressed in exponential form. Fig. 9 Figure 2 shows the area changes of the Poyang Lake-Ganjiang River delta front observed every 11 years from November to December 1973 to 2006.

[0042] Table 2 below shows the local area changes and average annual area change rate of the front edge of the Ganjiang fan delta in Poyang Lake observed in different years, with the interval of 0.60 at the beginning of the sedimentary phase sequence being 0.05. The results of fitting these data are shown in the figure below. Fig.10 and Fig.11 shown.

[0043]

[0044] Table 2 like Fig.12 As shown, in order to further verify the distribution patterns of each sedimentary subfacies and its plane, publicly published articles related to the sedimentary facies and its plane distribution patterns were selected. The following Table 3 shows the plane proportions of each sedimentary subfacies according to satellite images.

[0045]

[0046] Table 3 The lake area change rate and triangle area expansion rate were combined for fitting. From the fitting results, the continuously changing sedimentary phase and its area change rate were consistent with y=0.0272*e 2x Mathematical expressions.

[0047] like Fig.13 The above data are combined to obtain the following fan delta deposition plane distribution proportion fitting relationship. The correlation between these data reveals that the area proportion of each delta sedimentary phase or subphase observed on the plane conforms to the exponential model, which provides a basis for using seismic parameters to infer sedimentary phases through numerical plane proportion statistical analysis.

[0048] Specifically, the well-seismic data calibration association module: Use well logging acoustic waves, density data or seismic VSP data to make high-precision seismic synthetic records, calibrate the studied layer on the seismic section, and establish a corresponding relationship between well data and seismic data. The well and seismic calibration results are as follows: Fig.15 shown.

[0049] Specifically, the well point formation sand-to-formation ratio and sedimentary facies interpretation and fitting module: standardize the actual well logging curves in the study area to obtain the Vshl parameter interpreted with a unified logging standard, use the same threshold value to calculate the sand-to-formation ratio of each layer in different wells, and then fit it with the interpreted sedimentary facies to obtain the relationship between the sand-to-formation ratio and the continuous sedimentary facies; The actual well logging curves in the study area were standardized to obtain the Vshl parameter interpreted by the unified logging standard. By changing the Vshl threshold cutoff value, the ratio of the cumulative thickness to the layer thickness corresponding to different threshold values ​​was obtained. The Vshl threshold values ​​of 0.55 (T70-T71) and 0.45 where the standard deviation was the smallest were obtained, and Vshl < 0.48 was selected as the statistical standard for the upper and lower sand-to-ground ratio. As shown in Tables 4 and 5, Fig.16 and 17 shown.

[0050] Table 4

[0051] Table 5 Tables 6 and 7 below show the relationship between the sand content and thickness of each layer when the Vshl threshold value is 0.48:

[0052] Table 6

[0053] Table 7 Specifically, the seismic amplitude parameter algorithm selection module: by performing correlation analysis on the calculation results of different algorithms for commonly used seismic amplitude parameters, the seismic amplitude root mean square algorithm (Amplitudes RMS) with a better linear relationship is selected as the data source that best reflects the distribution law of sedimentary phases on the plane; The seismic amplitude parameter algorithm is selected by comparing the seismic amplitude root mean square RMS and negative polarity amplitude with two algorithms, and the algorithm with the best correlation with the Vshl threshold value of 0.48 is selected. Through comparative analysis: the correlation between the negative polarity amplitude of the seismic amplitude at the well point and the sand-to-ground ratio is poor, and the correlation between the seismic amplitude root mean square RMS and the sand-to-ground ratio is 0.994. The seismic amplitude attribute RMS algorithm is preferred for sedimentary phase prediction.

[0054] like Fig.18 and Fig.19 This is the relationship between the RMS value of the interlayer seismic amplitude and the sand-to-ground ratio (Vshl<0.48) around the Enping 1 (T70-T71) and Enping 2 (T71-EP210) wells.

[0055] Table 8 below and Fig. 20 and Fig.21 It is the statistics and correlation analysis of seismic amplitude attributes and sand-to-ground ratio data.

[0056]

[0057] Table 8 Specifically, the seismic amplitude root mean square data statistical analysis module: extract the seismic amplitude RMS value along the seismic interpretation plane or between layers, obtain the amplitude RMS value corresponding to each sampling coordinate point, and count the data at equal intervals, and obtain the seismic amplitude RMS value cumulative proportion curve by fitting; like Fig. 22 , Fig.23 and Fig.24 As shown in the figure, since the root mean square (RMS) of seismic amplitude can better reflect the change of sand-to-land ratio on the plane, the seismic amplitude RMS values ​​are extracted along the seismic interpretation plane or between layers. By statistically analyzing these data, the cumulative proportion distribution diagram of different value intervals is obtained, and the cumulative proportion fitting curve of seismic amplitude RMS values ​​is obtained by fitting the data. The cumulative proportion value of the numerical interval is the cumulative proportion of the seismic amplitude RMS numerical distribution corresponding to the plane area proportion of each sedimentary phase sequence observed in the modern Poyang Lake sediments.

[0058] Specifically, the module for fitting the modern sedimentary geological model and the seismic amplitude plane proportion is based on the mathematical geological model established for modern sedimentation, which is fitted with the seismic amplitude RMS plane proportion curve. By adjusting the power exponent value of the fitted curve, the relationship between the sedimentary phase area proportion and the sedimentation between modern and ancient sedimentation is optimized, and then the relationship between the seismic amplitude RMS plane proportion and the continuous sedimentary phase is obtained; The mathematical geological model established based on modern sedimentation is superimposed with the results of the plane proportion analysis of the cumulative seismic amplitude RMS value. In other words, the plane proportion relationship of the sedimentary facies observed based on modern sedimentation is applied to the analysis and prediction of ancient sedimentary facies. Based on the relationship between the sand-to-formation ratio and sedimentary facies analyzed by actual drilling, the value range of the sand-to-formation ratio and the subfacies area proportion corresponding to each sedimentary subfacies in the study area is determined.

[0059] Fig.25 Shown is the fitting relationship between continuous sedimentary phase sequence, sedimentary phase plane ratio, sand-to-ground ratio and seismic amplitude RMS: Based on the superposition results of modern sedimentation and the continuous sedimentary phase sequence and plane distribution proportion of the Paleogene Enping Formation (38-34Ma) in the study area, it can be calculated that the seismic amplitude RMS is linearly correlated with the continuous sedimentary phase sequence, and the coordinate axis x can be expressed by both the seismic amplitude RMS and the continuous sedimentary phase sequence.

[0060] like Fig.26 As shown, the cumulative proportion of the continuous sedimentary phase sequence distribution represented by the seismic amplitude RMS of ancient sediments is fitted by the formula y=4.455*e -2x , the proportion of each phase sequence of modern sedimentary continuous sedimentation area is y=0.027*e 2X Based on the similarity of the distribution of modern sedimentary and ancient sedimentary phase sequences on the plane, the equation is solved to obtain the expression between the continuous sedimentary phase sequence X and the seismic amplitude RMS value x:

[0061] After fitting, the continuous sedimentary phase sequence, sand-to-ground ratio and sedimentary phase plane ratio are as follows Fig. 27 and Fig.28 Shown relationship.

[0062] The fitting relationship between the continuous sedimentary phase sequence, sand-to-ground ratio, sedimentary phase plane proportion and seismic amplitude RMS is shown in Table 9:

[0063] Table 9 Specifically, the module for dividing the value range interval of sedimentary phases in the vertical and horizontal planes: the relationship between the continuous sedimentary phase and the plane proportion of the seismic amplitude RMS is obtained, combined with the relationship between the sand-to-ground ratio and the continuous sedimentary phase, the relationship between the sand-to-ground ratio and its proportion in the plane can be obtained, so as to determine the different value range division intervals of the continuous sedimentary phase sequence in the vertical and horizontal planes, as well as the value range interval of the sedimentary phase divided by the seismic amplitude RMS value; like Fig.29 As shown, a sedimentological analysis was conducted on the actual drilling geological data, and the sedimentary facies and subfacies were divided according to the sedimentary cycles.

[0064] like Fig.30 and Fig.31 As shown in the figure, the sedimentary analysis results are mapped to the statistical histogram of the seismic amplitude RMS data of the layer according to the RMS value of the seismic amplitude read at the well point; based on the sedimentary facies sand-to-formation ratio data of the drilled wells, combined with the sand-to-formation ratio division ranges corresponding to various sedimentary microfacies in regional sedimentology statistics, the amplitude RMS value range corresponding to the sand-to-formation ratio of the sedimentary subfacies and microfacies divided on the well is determined on the histogram.

[0065] Finally, the sedimentary phase division value ranges in both vertical and horizontal dimensions are obtained, which can reflect the sedimentary characteristics of this block. Table 10 below shows the value ranges of sedimentary phase area, sand-to-ground ratio, and seismic amplitude RMS sedimentary phase and subphase division obtained by combining the actual drilling sedimentary phase analysis results:

[0066] Table 10 Specifically, the sedimentary phase color plate assignment module is used to assign colors to the seismic amplitude RMS value ranges corresponding to different deposits on the seismic amplitude RMS numerical analysis diagram, so as to form a sedimentary phase color plate that can distinguish different deposits and present sedimentary characteristics.

[0067] Specifically, the seismic amplitude root mean square attribute sedimentary phase display module is used to apply the sedimentary phase color plate to the acquired seismic amplitude RMS data, and present the distribution range of each sedimentary phase in different colors on the plane.

[0068] like Fig.32 , Fig.33 and Fig.34 As shown, colors are assigned to the seismic amplitude RMS value ranges corresponding to different deposits on the histogram, forming a sedimentary phase color plate that can distinguish different sedimentary phases and present sedimentary characteristics, thereby realizing the quantitative seismic sedimentation prediction based on the seismic amplitude RMS.

[0069] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A sedimentary facies prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer, characterized in that: include: According to the distribution ratio of sedimentary phases observed in modern sedimentation, mathematical methods are selected to establish a mathematical geological model that conforms to the phase sequence change law, forming a prediction module for the plane distribution of ancient sedimentary phases based on modern sedimentary patterns; Well-seismic data calibration and association module, which produces seismic synthetic records based on drilling and seismic data, calibrates the studied layer section on the seismic section, and establishes the correspondence between drilling data and seismic data; Well-point formation sand-to-formation ratio and sedimentary facies interpretation fitting module determines the threshold value of the Vshl mud content parameter in the study area, uses the same threshold value to count the sand-to-formation ratio of each layer in different well sections, fits the sand-to-formation ratio with the interpreted sedimentary facies, and obtains the relationship between the sand-to-formation ratio and the continuous sedimentary facies; The seismic amplitude parameter algorithm selection module determines the seismic amplitude root mean square RMS algorithm as the data source reflecting the distribution law of sedimentary phases on the plane through analysis and comparison of the results of multiple algorithms; The seismic amplitude root mean square RMS data acquisition module extracts the seismic amplitude RMS value along the seismic interpretation plane or between layers to obtain the seismic amplitude RMS value cumulative proportion curve; The module for fitting the modern sedimentary geological model and the RMS proportion of seismic amplitude in the plane is based on the mathematical geological model established by modern sedimentation, and is fitted with the curve of the cumulative proportion of the RMS plane of seismic amplitude to obtain the relationship between the proportion of the RMS plane of seismic amplitude and the continuous sedimentary phase; The module for dividing the value range of sedimentary phases in the vertical and horizontal planes obtains the relationship between the sand-to-formation ratio and the proportion of continuous sedimentary phases in the plane according to the relationship between the cumulative proportion of the seismic amplitude RMS plane and the continuous sedimentary phases, combined with the relationship between the sand-to-formation ratio and the continuous sedimentary phases, thereby determining the value range of the sand-to-formation ratio and the seismic amplitude RMS value for dividing the sedimentary phases in the vertical and horizontal planes of the continuous sedimentary phase sequence.

2. The sedimentary facies prediction system based on the analysis of seismic amplitude attribute ratio at the layer according to claim 1 is characterized in that: The sedimentary phase prediction system also includes a sedimentary phase color plate allocation module, which specifies colors for seismic amplitude RMS value ranges corresponding to different deposits on the seismic amplitude RMS numerical analysis diagram to form a sedimentary phase color plate that can both distinguish different sedimentary phases and present sedimentary characteristics.

3. The sedimentary facies prediction system based on the analysis of the proportion of seismic amplitude attributes at the layer according to claim 2 is characterized in that: The sedimentary phase prediction system also includes a seismic amplitude root mean square attribute sedimentary phase display module, which applies a sedimentary phase color plate to the acquired seismic amplitude RMS data and presents the distribution range of each sedimentary phase in different colors on the plane.

4. The sedimentary facies prediction system based on the analysis of seismic amplitude attribute proportions at the layer level according to claim 1 is characterized in that: The module for establishing a geological mathematical model using modern sedimentation also performs statistical analysis based on changes in geological area to verify the relationship between sedimentary phases and the rate of change of geological area.

5. The sedimentary facies prediction system based on the analysis of seismic amplitude attribute ratio at the layer according to claim 1 is characterized in that: In the well-seismic data calibration association module, the drilling and seismic data are well acoustic waves, density data and seismic VSP data.

6. The sedimentary facies prediction system based on the analysis of seismic amplitude attribute ratio at the layer according to claim 1 is characterized in that: In the well point formation sand-to-ground ratio and sedimentary phase interpretation fitting module, the Vshl parameter threshold value of the study area is determined to be the optimal value of the correlation after the actual drilling logging curve of the study area is standardized.

7. The sedimentary facies prediction system based on the analysis of seismic amplitude attribute ratio at the layer according to claim 1 is characterized in that: In the seismic amplitude parameter algorithm selection module, the analysis is to perform a correlation analysis on the calculation results of different algorithms for commonly used seismic amplitude parameters.

8. The sedimentary facies prediction system based on the analysis of seismic amplitude attribute ratio at the layer according to claim 1 is characterized in that: In the seismic amplitude root mean square RMS data acquisition module, seismic amplitude RMS values ​​are counted at equal intervals.

9. The sedimentary facies prediction system based on the analysis of seismic amplitude attribute ratio at the layer according to claim 1 is characterized in that: In the modern sedimentary geological model and the RMS proportion fitting module of the layer seismic amplitude, the power exponent value of the fitting curve is adjusted to make the sedimentary phase area proportion and sedimentation relationship between modern sedimentation and ancient sedimentation match.

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