Method and system for identifying continuous change in depositional environment

Abstract

The application discloses a method and system for identifying continuous change of a deposition environment, and relates to the technical field of oil exploration. The method comprises the following steps: performing single-element semi-quantitative profile numericalization on the result of continuous scanning of a profile of a sample; performing superposition operation on the information after the single-element semi-quantitative profile numericalization to obtain a parameter profile distribution value reflecting combined element information; obtaining a combined element parameter profile distribution value image after imaging the parameter profile distribution value; and identifying the deposition environment according to the change of the combined element parameter profile distribution value image. The application can intuitively identify the deposition environment in which a deposition sample is located and the transformation rule of the deposition environment, solves the identification method mainly based on single-point data collection and analysis all the time, realizes the change of XRF element analysis content from qualitative to quantitative, and makes the identification of continuous deposition more accurate.

Description

Technical Field

[0001] This invention relates to the field of petroleum exploration technology experiments, and in particular to a method and system for identifying continuous changes in sedimentary environments. Background Technology

[0002] The sedimentary environment in which clastic and carbonate rocks are deposited has a significant impact on the subsequent physical and chemical alterations of sediments. Particularly in oil and gas exploration, favorable source rocks generally develop in specific sedimentary environments, such as reducing or saline environments. Oxidizing environments tend to destroy organic matter, thus diminishing hydrocarbon generation capacity, while saline environments are more conducive to microbial production and accumulation. Furthermore, arid or humid environments significantly influence diagenesis following clastic rock deposition, ultimately affecting the development of pore space in oil and gas reservoirs. Therefore, identifying the sedimentary environment of rocks is crucial for predicting favorable oil and gas exploration areas. Currently, the identification of sedimentary environments primarily utilizes the distribution range of trace element or rare earth element combination parameters in rock minerals. This method requires crushing the rock sample to collect a sample from a single location for elemental analysis. This method not only damages the sample but can only analyze the sample from one location. Although continuous sampling is possible, the variation of sedimentary rhythm in the core is at the millimeter level. Due to the influence of the sampling interval, the continuous single-point sampling method cannot reflect the changing characteristics of the continuous sedimentary environment, and therefore cannot identify the changes in the continuous sedimentary environment.

[0003] Traditional fragmented sampling analysis methods suffer from problems such as long processing times, high costs, complex sample handling, and a tendency to cause contamination. The use of handheld X-ray fluorescence spectrometry (XRF) to perform simple elemental assemblages to reflect sedimentary environments has only been applied at single sampling points. Due to the limitations of XRF's working principle, XRF scans can only qualitatively determine the types of elements. Although the intensity of fluorescent X-rays is related to the content of corresponding elements, many factors influence the quantitative identification of elemental content. Therefore, its application in quantitative elemental analysis has been limited, and there are no reports of continuous quantitative elemental identification in sedimentary rocks. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for identifying continuous changes in sedimentary environments, solving the problem of traditional methods that primarily rely on single-point data acquisition and analysis. It also enables a shift from qualitative to quantitative XRF elemental analysis of sediment content, making the identification of continuous sedimentation more accurate. To achieve the above objectives, this invention provides the following technical solution:

[0005] On the one hand, the present invention provides a method for identifying continuous changes in sedimentary environments, the method comprising the following steps:

[0006] The results of continuous scanning of the sample profile are quantified into single-element semi-quantitative profiles.

[0007] The information after the numericalization of the single-element semi-quantitative profile is superimposed to obtain the parameter profile distribution value that reflects the information of the combined elements.

[0008] The combined element parameter profile distribution value image is obtained by visualizing the parameter profile distribution value.

[0009] The depositional environment is identified based on the changes in the profile distribution values ​​of the combined element parameters.

[0010] Furthermore, the method also includes the following steps:

[0011] Cut the sample along the vertical layering plane;

[0012] The cross-section of the sample was subjected to continuous scanning using X-ray fluorescence spectroscopy.

[0013] Furthermore, the sample is a core sample or a sample collected in the field;

[0014] The sample has the following characteristics:

[0015] The core samples are block samples obtained through continuous core extraction;

[0016] The samples collected in the field are blocky samples from field outcrops, and the top and bottom of the deposits can be determined.

[0017] Furthermore, the sample profile is a fresh surface and shows depositional characteristics.

[0018] Furthermore, the sedimentation environment includes: redox environment, arid climate environment, warm and humid climate environment, marine environment and freshwater environment.

[0019] Based on the above method, the present invention also provides a system for identifying continuous changes in the sedimentary environment, the system comprising: a numerical unit, a computation unit, an image processing unit, and an identification unit, wherein...

[0020] The numericalization unit is used to perform single-element semi-quantitative profile numericalization of the results of continuous scanning of the sample profile.

[0021] The calculation unit is used to superimpose the information of the single-element semi-quantitative profile after numericalization to obtain the parameter profile distribution value reflecting the information of the combined elements.

[0022] The image processing unit is used to image the parameter profile distribution values ​​to obtain a combined element parameter profile distribution value image;

[0023] The identification unit is used to identify the deposition environment based on the changes in the profile distribution value image of the combined element parameters.

[0024] Furthermore, the system also includes:

[0025] Cutting unit, used to cut along the vertical bedding plane;

[0026] The scanning unit is used to continuously scan the sample profile in an X-ray fluorescence spectrum.

[0027] Furthermore, the sample is a core sample or a sample collected in the field;

[0028] The sample has the following characteristics:

[0029] The core samples are block samples obtained through continuous core extraction;

[0030] The samples collected in the field are blocky samples from field outcrops, and the top and bottom of the deposits can be determined.

[0031] Furthermore, the sample profile is a fresh surface and shows depositional characteristics.

[0032] Furthermore, the sedimentation environment includes: redox environment, arid climate environment, warm and humid climate environment, marine environment and freshwater environment.

[0033] The technical effects and advantages of this invention are as follows:

[0034] By continuously scanning the profiles of core samples or samples collected in the field using XRF, and performing combined element superposition operations on the scanned single-element semi-quantitative data, and generating images based on the relationship between numerical values ​​and color intensity, the depositional environment of the sedimentary sample and the changing patterns of the depositional environment can be intuitively identified. This solves the problems of incomplete information reflection, sample damage, and long time cycles in the single-point identification process.

[0035] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0036] Figure 1 This is a flowchart of a method for identifying continuous changes in sedimentary environment according to the present invention;

[0037] Figure 2 This is a schematic diagram illustrating the specific process of a method for identifying continuous changes in the sedimentary environment according to the present invention;

[0038] Figure 3This is a relative abundance diagram of V element in the core axial section of the present invention;

[0039] Figure 4 This is a diagram showing the relative abundance of Cr in the core axial section of the rock core according to the present invention.

[0040] Figure 5 This is a distribution diagram of element V content in this embodiment;

[0041] Figure 6 This is a diagram showing the content distribution of Ni element in this embodiment;

[0042] Figure 7 This is a schematic diagram illustrating the evolution of the sedimentary environment during continuous deposition, as obtained by the method in this embodiment. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] To address the shortcomings of existing technologies, this invention discloses a method for identifying continuous changes in the sedimentary environment, such as... Figure 1 This is a flowchart of a method for identifying continuous changes in sedimentary environments according to the present invention. The method includes the following steps:

[0045] The continuous scanning results of the sample profile are quantified into single-element semi-quantitative profiles.

[0046] The information after the numericalization of the single-element semi-quantitative profile is superimposed to obtain the parameter profile distribution value that reflects the information of the combined elements.

[0047] The combined element parameter profile distribution value image is obtained by visualizing the parameter profile distribution value.

[0048] The depositional environment is identified based on the changes in the profile distribution values ​​of the combined element parameters.

[0049] Preferably, the method further includes the following steps:

[0050] Cut the sample along the vertical layering plane;

[0051] The cross-section of the sample was subjected to continuous scanning using X-ray fluorescence spectroscopy.

[0052] Based on the above method, the present invention also discloses a system for identifying continuous changes in the sedimentary environment, the system comprising: a numerical unit, a computation unit, an image processing unit, and an identification unit, wherein...

[0053] The numericalization unit is used to perform single-element semi-quantitative profile numericalization of the continuous scanning results of the sample profile.

[0054] The calculation unit is used to superimpose the information of the single-element semi-quantitative profile after numericalization to obtain the parameter profile distribution value reflecting the information of the combined elements.

[0055] The image processing unit is used to image the parameter profile distribution values ​​to obtain a combined element parameter profile distribution value image;

[0056] The identification unit is used to identify the deposition environment based on the changes in the profile distribution value image of the combined element parameters.

[0057] Preferably, the system further includes: a cutting unit and a scanning unit;

[0058] The cutting unit is used to cut the sample along the perpendicular layering plane;

[0059] The scanning unit is used to continuously scan the sample profile in an X-ray fluorescence spectrum.

[0060] Limited by XRF instruments, only the types and percentages of elements can be determined, not the precise values ​​of a particular element. This invention, through the following methodological transformation, achieves numerical values ​​that reflect the characteristics of elemental combinations, thereby reflecting the sedimentary environment.

[0061] The above method and system are described below with reference to specific embodiments. The sample used in this embodiment is a core sample, which is a block sample obtained by continuous coring. The block sample has a definite top and bottom of deposition, and the test profile after cutting is a fresh surface.

[0062] like Figure 2 This is a schematic diagram illustrating a specific process for a method to identify continuous changes in the sedimentary environment according to this embodiment. The identification method includes the following steps:

[0063] Step 1: Cut the core sample along the vertical bedding plane and place the profile that will show the sedimentary features in a high-resolution XRF.

[0064] Preferably, if the sample collected in the field is a blocky sample with a defined top and bottom of deposition, and the test profile after cutting is a fresh surface, it is also applicable to the present invention.

[0065] Step 2: Place the fresh profile of the cut sample showing deposition features into a high-resolution XRF scanner for continuous scanning.

[0066] Step 3: The abundance distribution data of various elements on the profile formed by continuous XRF scanning is used to form the numerical distribution of the relative abundance of single elements on the profile using computer software.

[0067] Preferably, elements sensitive to changes in the sedimentary environment are selected, and numerical distribution profiles of the relative abundance of these elements are formed. Elements sensitive to redox environments include V, Cr, Ni, and combinations of other elements; elements relatively sensitive to dry and humid climates include Sr, Cu, and combinations of other elements; elements sensitive to seawater, freshwater, and intermediate water-bearing media include Sr, Ba, and combinations of other elements.

[0068] Step 4: Based on the element combination parameters of the sedimentary environment, the numerical distribution profile of the relative abundance of individual elements is transformed into a mass content percentage value that can be compared between elements by using the relative mass ratio between each element. Then, according to the characteristics of the element combination, the mass content percentage values ​​are superimposed to obtain the profile distribution value that reflects the information parameters of the combined elements.

[0069] Step 5: Based on the relationship between the numerical value and color intensity, the parameter profile distribution values ​​are visualized to obtain a combined element parameter profile distribution value image.

[0070] Step 6: Identify the depositional environment based on the changes in the profile distribution values ​​of the combined element parameters.

[0071] Preferably, the identifiable sedimentary environments include: redox environments, arid climate environments, warm and humid climate environments, marine environments, and freshwater environments.

[0072] like Figure 3 This is a relative abundance map of V element along the core axial section in an embodiment of the present invention. Specifically, it is a relative abundance map of V element along the core axial section extracted from the XRF scanned data volume using computer software. Figure 4 The relative abundance map of Cr element in the axial section of the core in this embodiment of the invention is specifically a relative abundance map of Cr element in the axial section of the core extracted by computer software from the XRF scan data volume. A single-element planar abundance map only reflects the difference in the content of that element on a plane and cannot be compared with other elements. Figure 3 and Figure 4The varying shades of color reflect the differences in the abundance of an element on a plane, but only reflect the abundance of that element itself; it is not comparable to other elements, a limitation inherent to the instrument. However, the instrument can provide the normalized mass percentage of elements on the cross-section. By redistributing the normalized mass percentage of a single element according to its abundance, the mass percentage value of each element in each numerical grid can be obtained, thus forming the numerical distribution of the relative abundance of a single element on the cross-section. Further, by performing one-to-one correspondence calculations on the grid values ​​of each element, precise ratios of different element combinations can be obtained. Sensitive elements can then be selected, and the characteristic values ​​of element combinations can be used to reflect the continuous variation characteristics of the sedimentary environment.

[0073] Taking the combined parameter of sensitive elements V and Ni, V / (V+Ni)>0.84 as an example to reflect an oxygen-rich oxidation deposition environment, such as... Figure 5 This is an abundance distribution diagram of element V in this embodiment, as shown below. Figure 6 This is an abundance distribution diagram of Ni element in this embodiment.

[0074] To avoid excessive data volume, this time... Figure 5 Taking the planar abundance map of element V as an example, the abundance values ​​of element V within the selected area of ​​the white box are processed by computer software and converted into a numerical distribution map of the relative mass content of element V. As shown in Table 1, the relative mass content of each element in the sample obtained by continuous XRF scanning is 0.0349% and the relative content of Ni is 0.0054%.

[0075] Table 1. Relative content of each element in the sample obtained by continuous XRF scanning.

[0076] element Atomic number mass percentage Atomic percentage Na(sodium) 11 7.2304％ 6.9415％ O (oxygen) 8 42.3115％ 58.3694％ Mg (Magnesium) 12 2.0572％ 1.8681％ K (potassium) 19 3.4354％ 1.9393％ Ca (calcium) 20 11.4142％ 6.2860％ Ti (Titanium) 22 0.5336％ 0.2460％ Si (silicon) 14 22.39880％ 17.6024％ Al (aluminum) 13 6.0699％ 4.9653％ Fe (iron) 26 4.351％ 1.7166％ Sr (Strontium) 38 0.1038％ 0.0262％ Ni(Nickel) 28 0.0054％ 0.0020％ V (vanadium) 23 0.0349％ 0.0151％ Rb (rubidium) 37 0.0158％ 0.0041％ Cr (chromium) 24 0.0381％ 0.0181％ Total content \ 100％ 100％

[0077] Next to Figure 5 The values ​​in the white box are gridded and assigned as shown in Table 2. Assuming the number of grids is 100, the sum of all totals in the grid is S = a1 + ... + a10 + b1 + ... + b10 + ... + j1 + ... + j10.

[0078] Table 2 Figure 5 The value assignment table for the numerical gridded region within the white box

[0079] \ a b c d e f g h i j 1 a1 b1 c1 d1 e1 f1 g1 h1 i1 j1 2 a2 b2 c2 d2 e2 f2 g2 h2 i2 j2 3 a3 b3 c3 d3 e3 f3 g3 h3 i3 j3 4 a4 b4 c4 d4 e4 f4 g4 h4 i4 j4 5 a5 b5 c5 d5 e5 f5 g5 h5 i5 j5 6 a6 b6 c6 d6 e6 f6 g6 h6 i6 j6 7 a7 b7 c7 d7 e7 f7 g7 h7 i7 j7 8 a8 b8 c8 d8 e8 f8 g8 h8 i8 j8 9 a9 b9 c9 d9 e9 f9 g9 h9 i9 j9 10 a10 b10 c10 d10 e10 f10 g10 h10 i10 j10

[0080] S V S is the sum of the abundance values ​​in the V element grid. Ni The sum of the total abundance values ​​of Ni across all grids is 0.0349% / S. V Multiplying this by the value in a single grid cell gives the mass V of element V relative to other elements in each grid cell. xy(Where x represents the column and y represents the row, indicating each numerical grid); similarly, 0.0054% / S Ni Multiplying this by the value in a single grid cell represents the mass of Ni relative to other elements in each grid cell (Ni). xy Then V xy / (V xy +Ni xy This allows us to derive the element ratios between corresponding grids, thus enabling accurate measurement of the ratios between element combinations without precisely measuring the absolute content of elements at individual points. Furthermore, it allows us to derive the ratio of V / (V+Ni) for the entire plane. Visualizing this ratio—that is, by correlating the magnitude of the value with color intensity—provides a more intuitive understanding of changes in the depositional environment. Figure 7 This is a schematic diagram illustrating the evolution of the sedimentary environment during a continuous deposition process, derived from the method described in this embodiment. From... Figure 7 It can be seen that the rock underwent an oxidizing environment → reducing environment → oxidizing environment → reducing environment → predominantly oxidizing environment → transitioning from oxidizing environment to reducing environment → predominantly reducing environment during the deposition process.

[0081] This example only illustrates the method for identifying redox environments. However, arid or humid climate environments, as well as marine or freshwater environments, can all be identified intuitively using the same method. This solves the problem of the previous identification method that relied mainly on single-point data collection and analysis, and greatly improves the accuracy of identifying continuous sediments.

[0082] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for identifying continuous changes in sedimentary environments, characterized in that, The method includes the following steps: The continuous scanning results of the sample profile are quantified into single-element semi-quantitative profiles. The information from the numericalized single-element semi-quantitative profile is superimposed to obtain the parameter profile distribution value reflecting the information of the combined elements. Specifically, this includes: based on the element combination parameters for identifying the sedimentary environment, the numerical distribution profile of the relative abundance of single elements is converted into a mass content percentage value that can be compared between elements by using the relative mass ratio between each element. Then, based on the characteristics of the element combination, the mass content percentage values ​​are superimposed to obtain the profile distribution value reflecting the information parameters of the combined elements. The combined element parameter profile distribution value image is obtained by visualizing the parameter profile distribution value; specifically, it includes: visualizing the parameter profile distribution value according to the relationship between the numerical value and the color intensity to obtain the combined element parameter profile distribution value image. The depositional environment is identified based on the changes in the profile distribution values ​​of the combined element parameters.

2. The method for identifying continuous changes in sedimentary environment according to claim 1, characterized in that, The method further includes the following steps: Cut the sample along the vertical layering plane; The cross-section of the sample was subjected to continuous scanning using X-ray fluorescence spectroscopy.

3. A method for identifying continuous changes in sedimentary environment according to claim 1 or 2, characterized in that, The sample is a core sample or a sample collected in the field; The sample has the following characteristics: The core samples are block samples obtained through continuous core extraction; The samples collected in the field are blocky samples from field outcrops, and the top and bottom of the deposits can be determined.

4. The method for identifying continuous changes in sedimentary environment according to claim 1, characterized in that, The sample profile was fresh and showed depositional characteristics.

5. The method for identifying continuous changes in sedimentary environment according to claim 1, characterized in that, The sedimentary environments include redox environments, arid climate environments, warm and humid climate environments, marine environments, and freshwater environments.

6. A system for identifying continuous changes in sedimentary environments, characterized in that, The system includes: a numericalization unit, a computation unit, an image processing unit, and a recognition unit, wherein... The numericalization unit is used to perform single-element semi-quantitative profile numericalization of the continuous scanning results of the sample profile. The calculation unit is used to superimpose and calculate the information of the single-element semi-quantitative profile after numericalization to obtain the parameter profile distribution value reflecting the information of the combined elements; specifically, it includes: based on the element combination parameters for identifying the sedimentary environment, the numerical distribution profile of the relative abundance of the single element is converted into the relative abundance profile of the elements that cannot be compared between the elements by using the relative mass ratio between each element, and then the mass content percentage values ​​are superimposed and calculated according to the characteristics of the element combination to obtain the profile distribution value reflecting the information parameters of the combined elements. The image processing unit is used to image the parameter profile distribution values ​​to obtain a combined element parameter profile distribution value image; specifically, it includes: image processing the parameter profile distribution values ​​according to the relationship between numerical value and color intensity to obtain a combined element parameter profile distribution value image; The identification unit is used to identify the deposition environment based on the changes in the profile distribution value image of the combined element parameters.

7. A system for identifying continuous changes in sedimentary environment according to claim 6, characterized in that, The system also includes: a cutting unit and a scanning unit; The cutting unit is used to cut the sample along the perpendicular layering plane; The scanning unit is used to continuously scan the sample profile in an X-ray fluorescence spectrum.

8. A system for identifying continuous changes in sedimentary environment according to claim 7, characterized in that, The sample is a core sample or a sample collected in the field; The sample has the following characteristics: The core samples are block samples obtained through continuous core extraction; The samples collected in the field are blocky samples from field outcrops, and the top and bottom of the deposits can be determined.

9. A system for identifying continuous changes in sedimentary environment according to claim 6, characterized in that, The sample profile was fresh and showed depositional characteristics.

10. A system for identifying continuous changes in sedimentary environment according to claim 6, characterized in that, The sedimentary environments include redox environments, arid climate environments, warm and humid climate environments, marine environments, and freshwater environments.

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