Construction method and identification method of shale oil stratigraphic development degree identification chart
By constructing a bedding development degree identification chart based on geochemical parameters, the problems of accuracy and efficiency in identifying the bedding development degree of shale oil formations were solved, achieving rapid and accurate bedding identification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2026-03-31
AI Technical Summary
In existing technologies, the identification of the bedding development of shale oil formations relies on core observation and thin section analysis, which is greatly affected by human factors and is inefficient, making it difficult to achieve rapid and accurate identification.
Elemental logging technology was used to analyze the geochemical parameters of shale core or cuttings samples. Cross plots were established based on geochemical parameters that were strongly correlated with the degree of bedding development, and a bedding development identification plot was constructed to evaluate the degree of bedding development in shale oil formations in real time.
It improves the accuracy and efficiency of shale oil formation bedding identification, overcomes the limitations of existing technologies that rely on core observation and thin section analysis, and provides a simple, low-cost, and rapid identification method.
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Figure CN121760701A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of petroleum engineering technology, specifically relating to a method for constructing a bedding development identification map of shale oil formations based on formation elements. Furthermore, this invention also relates to a method for identifying the bedding development degree of shale oil formations based on formation elements. Background Technology
[0002] In my country, continental shale formations are widely bedding-developed, and the degree of bedding development significantly affects the oil-bearing capacity, reservoir properties, mobility, and compressibility of shale formations. Based on the different bedding development conditions, shale is generally classified into three categories: laminated shale (bedding thickness < 1 mm); layered shale (bedding thickness > 1 mm); and massive shale (bedding is not well developed). Laminated and layered shale formations typically have better reservoir properties, more developed porosity and fractures, and higher shale oil production. Currently, the identification of shale sedimentary structures mainly uses core observation and thin-section analysis. Core observation is greatly influenced by human factors, and different geologists describe bedding development characteristics inconsistently. Thin-section analysis, due to its operational complexity, is difficult to perform large-scale and rapid bedding identification. Because the scale of continental shale oil formations in my country is small, sensitive to climate and provenance, and has diverse vertical and longitudinal lithofacies types, real-time evaluation of the target shale layer is necessary during horizontal well drilling for shale oil. In addition, the evaluation of the degree of shale bedding development at the drilling site mainly relies on the description of rock cuttings, but there is a problem that the rock cuttings are small and the description is inaccurate when viewed with the naked eye.
[0003] Therefore, proposing a method for constructing a bedding development degree identification chart for shale oil formations and a method for identifying the degree of bedding development, in order to further provide guidance for field operations, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention
[0004] The purpose of this invention is to overcome the current problem that shale oil formation bedding identification relies on core and thin section observations and lacks reliable well site identification methods. It provides a method for constructing a bedding development degree identification chart for shale oil formations based on formation elements, and a method for identifying the degree of bedding development. Innovatively, it uses shale formation element data and analyzes the correlation between formation element geochemical parameters and bedding development characteristics to establish a reliable method for identifying the degree of bedding development, thereby improving the accuracy and efficiency of bedding identification at drilling sites.
[0005] One of the objectives of this invention is to provide a method for constructing a map for identifying the degree of bedding development in shale oil formations, comprising:
[0006] S1: Conduct elemental analysis on shale core or rock fragment samples to obtain geochemical parameters of the formation;
[0007] S2: Conduct core observations on shale cores or rock fragments to determine the degree of bedding development in the strata;
[0008] S3: Based on the geochemical parameters and the degree of bedding development, obtain geochemical parameters that are strongly correlated with the degree of bedding development;
[0009] S4: Based on the geochemical parameters that are strongly correlated with the degree of bedding development, a bedding development identification map is obtained.
[0010] In a preferred embodiment of the present invention, in step S1,
[0011] S11: Elemental logging technology is used to conduct elemental analysis on shale core or cuttings samples to obtain elemental content data;
[0012] S12: Based on elemental content data, the geochemical parameters of the strata are obtained.
[0013] In a preferred embodiment of the present invention, in step S1,
[0014] The geochemical parameters include, but are not limited to, at least one of paleoreducibility, chemical weathering intensity, paleosalinity, paleowater depth, sedimentation rate, paleosource, and paleoclimate index.
[0015] In a preferred embodiment of the present invention, in step S2,
[0016] The core observation includes at least one of direct observation and microscopic observation.
[0017] In a preferred embodiment of the present invention, in step S2,
[0018] The degree of bedding development includes massive shale, lamellar shale, and layered shale.
[0019] In a preferred embodiment of the present invention, in step S3,
[0020] S31: Based on the geochemical parameters, the degree and depth of bedding development, a columnar section is established;
[0021] S32: By comparing the geochemical parameters and bedding development degree within the same depth segment in the columnar section, geochemical parameters that are strongly correlated with the bedding development degree are obtained.
[0022] In a preferred embodiment of the present invention, in step S4,
[0023] S41: Establish cross plots for each pair of geochemical parameters that are strongly correlated with the degree of bedding development;
[0024] S42: Select intersection maps with clear boundaries and distribution areas of bedding development to obtain bedding development identification maps.
[0025] In a preferred embodiment of the present invention, in step S42,
[0026] Intersection maps with clear distribution areas and boundaries of bedding development degree and a matching rate of not less than 85% were selected to obtain bedding development degree identification maps.
[0027] The second objective of this invention is to provide a method for identifying the degree of bedding development in shale oil formations, including...
[0028] (1) Conduct elemental analysis on the shale core or rock fragment samples to be identified to obtain the geochemical parameters of the strata to be identified;
[0029] (2) The geochemical parameters of the strata to be identified are plotted onto the bedding development degree identification chart obtained by the construction method described in one of the objectives of this invention, so as to obtain the bedding development degree of the strata to be identified.
[0030] In a preferred embodiment of the present invention, in step (1), elemental logging technology is used to conduct elemental analysis on the shale core or rock cutting sample to be identified, and the elemental content data of the stratum to be identified is obtained; based on the elemental content data of the stratum to be identified, the geochemical parameters of the stratum to be identified are obtained.
[0031] Compared with the prior art, the beneficial effects of the present invention are:
[0032] 1. The method for constructing a bedding development degree identification chart for shale oil formations of the present invention analyzes the correlation between formation element geochemical parameters (paleoreducibility, paleowater depth, paleoclimate, sedimentation rate, intensity of chemical weathering, etc.) and bedding development degree, selects combinations of element geochemical parameters strongly correlated with bedding development degree, and then establishes a bedding development degree identification cross-plot for identifying bedding development degree, thereby providing a method for identifying bedding development degree while drilling for shale oil horizontal wells.
[0033] 2. The method for constructing a bedding development degree identification chart for shale oil formations of the present invention has a high consistency rate in the established bedding development degree identification intersection chart, which can accurately identify the bedding development degree of shale oil formations and overcome the limitations of the prior art, which relies on core observation and thin section analysis for bedding development degree identification of shale oil formations and has poor identification effect of bedding development degree in horizontal sections.
[0034] 3. The method for constructing a bedding development degree identification chart for shale oil formations according to the present invention adopts the widely used elemental logging technology. On the one hand, the identification method of the present invention is simple to operate, low in cost, and can perform large-scale and rapid bedding identification, with a wide range of applications. On the other hand, the identification method of the present invention can establish a bedding development degree identification cross-plot solely based on logging element data, which is timely and continuous, overcoming the limitations of existing technologies that rely on core observation and thin section analysis for bedding development degree identification in shale oil formations and have low efficiency in identifying bedding development degree in horizontal sections. Attached Figure Description
[0035] Figure 1 This is a schematic diagram illustrating the method for constructing a shale oil formation bedding development degree identification chart according to the present invention;
[0036] Figure 2 This is a schematic diagram illustrating the correlation analysis between the degree of bedding development and geochemical parameter characteristics in the method for constructing a bedding development identification chart for shale oil formations according to the present invention.
[0037] Figure 3 The paleowater depth-paleoclimate index intersection plot is used in the method for constructing a shale oil stratigraphic bedding development degree identification plot of the present invention.
[0038] Figure 4 This invention provides a paleopropagation-paleoclimate index intersection chart for the construction of a shale oil stratigraphic bedding development identification chart.
[0039] Figure 5 This invention provides a paleosource-paleowater depth intersection chart for the construction method of a shale oil stratigraphic bedding development degree identification chart. Detailed Implementation
[0040] In this invention, the matching rate refers to the degree of matching between data points in a cross-plot and regions with different bedding development levels; that is, the proportion of data points falling within regions that match their bedding development levels among all data points. In practical applications, the matching rate can be used to evaluate the accuracy of cross-plot analysis.
[0041] The present invention will now be described in further detail with reference to the accompanying drawings: Figure 1 As shown, this invention provides a method for constructing a map for identifying the degree of bedding development in shale oil formations. The main steps are as follows:
[0042] S1: Conduct elemental analysis on shale core or cuttings samples, i.e., extract elemental content data of shale formations from pilot wells or adjacent wells of the shale oil horizontal well to be drilled, and conduct elemental geochemical analysis of the shale formations; preferably, elemental analysis should be performed on shale cores. It should be noted that the elemental analysis here includes measurement results of different depths and different categories of elements. The specific steps are as follows:
[0043] S11: Perform elemental analysis on core or cuttings samples from the target layer in the pilot well or adjacent well to obtain elemental content data. Preferably, elemental logging technology is used to perform elemental analysis on core or cuttings samples from the target layer in the pilot well or adjacent well to obtain elemental logging data. It should be noted that elemental logging technology for shale oil horizontal wells is a mature technology. Generally, a small X-ray fluorescence spectrometer (elemental logging instrument) is used to analyze and test core or cuttings samples. The samples need to be dried and ground. Generally, all major elements and major trace elements can be measured, with more than 20 types of elements measured. The measurement results are the mass fractions of each element. For specific methods of elemental logging technology, please refer to "Research on the Application Method of X-ray Fluorescence Elemental Logging Technology" published by Daqing Drilling Engineering Company Geological Logging Company No. 1 in "Western Exploration Engineering" in 2023. The advantages of elemental logging technology are its simple operation and high timeliness, enabling operations such as cuttings retrieval, elemental measurement, and elemental analysis to be completed during drilling.
[0044] S12: Based on elemental content data, preferably elemental logging data, the geochemical parameters of the strata are calculated. It should be noted that step S12 ultimately yields values for different geochemical parameters at different depths. Preferably, the geochemical parameters include, but are not limited to, paleoreducibility, chemical weathering intensity, paleosalinity, paleowater depth, sedimentation rate, paleoprovince, and paleoclimate index. The calculation methods and representative meanings of each parameter are shown in Table 1.
[0045] Table 1 Geochemical parameters of commonly used elements
[0046]
[0047]
[0048] It should be noted that the second column of Table 1, "Calculation Formula," involves many elements, and these elements refer to their mass fraction. The following example uses paleosalinity to illustrate its calculation formula.
[0049]
[0050] In equation (1), Index 古盐度 W is the paleosalinity index. Sr W represents the mass percentage of strontium (Sr); Ba This represents the mass percentage of barium (Ba).
[0051] S2: Core observation is conducted on shale core or rock fragment samples to determine the degree of bedding development. It should be noted that the degree of bedding development here includes bedding development at different depths. Preferably, the core observation includes direct observation or microscopic observation; wherein, core observation is direct observation with the naked eye, and microscopic observation is observation using a microscope; the focus of core observation is on observing the degree of bedding development. Specifically, for the aforementioned shale core or rock fragment samples, the degree of bedding development is determined through direct observation or microscopic observation. More preferably, the degree of bedding development includes massive shale, lamellar shale, and layered shale. When conducting core observation, if bedding is not developed, the degree of bedding development is massive shale; if bedding is developed, the thickness of the bedding is measured; if it is less than 1 mm, the degree of bedding development is lamellar shale, and if it is greater than 1 mm, the degree of bedding development is layered shale. Direct observation and microscopic observation are conventional techniques in this field and will not be elaborated further here.
[0052] It should be noted that steps S1 and S2 of the present invention do not constitute a limitation on the order of the invention; they can be performed simultaneously or at different times.
[0053] S3: Based on the geochemical parameters of the strata in step S1 and the degree of bedding development in step S2, obtain geochemical parameters that are strongly correlated with the degree of bedding development. Preferably, S31: Based on the geochemical parameters and the degree of bedding development, establish a columnar section; S32: Compare the geochemical parameters and the degree of bedding development within the same depth segment in the columnar section to obtain geochemical parameters that are strongly correlated with the degree of bedding development.
[0054] Specifically, step S1 yields values for different geochemical parameters at different depths, while step S2 yields the degree of bedding development at different depths. Therefore, using the specific values at different depths as the ordinate, bar charts for bedding development and different geochemical parameters are established. The "bar charts for different geochemical parameters" here include, but are not limited to, bar charts for paleoreduction, chemical weathering intensity, paleosalinity, paleowater depth, sedimentation rate, paleoprovince, and paleoclimate indices. The bar charts for geochemical parameters and bedding development at the same depth are compared. If the value of a certain geochemical parameter at the same depth is strongly correlated with the degree of bedding development, then that geochemical parameter is a geochemical parameter strongly correlated with the degree of bedding development; if the value of a certain geochemical parameter at the same depth is weakly correlated with the degree of bedding development, then that geochemical parameter is not a geochemical parameter strongly correlated with the degree of bedding development.
[0055] For example, taking the comparison between the source Si and the degree of bedding development as an example, the mass fraction of source Si is relatively low in the depth range of layered shale with a degree of bedding development; when the degree of bedding development transitions to the depth range of massive shale, the mass fraction of source Si increases significantly, and this pattern remains consistent in most depth ranges, indicating that the source Si parameter is strongly correlated with the degree of bedding development. Source Si is a geochemical parameter that is strongly correlated with the degree of bedding development.
[0056] S4: Based on the geochemical parameters strongly correlated with the degree of bedding development in step S3, a bedding development degree identification map is obtained. Preferably, S41: Cross-plots are established for each pair of geochemical parameters strongly correlated with the degree of bedding development; S42: Cross-plots with clear distribution areas and boundaries of bedding development degree are selected to obtain the bedding development degree identification map. Specifically, cross-plots are established for each pair of geochemical parameters strongly correlated with the degree of bedding development in step S3, and cross-plots with clear distribution areas and boundaries of shale with different bedding development degrees are selected as the bedding development degree identification map. Here, "clear distribution areas and boundaries of shale with different bedding development degrees" means that the distribution areas of data points with different bedding development degrees on the cross-plot do not overlap significantly and have regional characteristics. More preferably, cross-plots with clear distribution areas and boundaries of bedding development degree and a conformity rate of not less than 85% are selected to obtain the bedding development degree identification map. The paleodepth-paleoclimate index intersection chart is used as an example. Each intersection point consists of two data points: the paleodepth and the paleoclimate index at the same depth.
[0057] This invention also provides a method for identifying the degree of bedding development in shale oil formations, comprising the following steps:
[0058] (1) Conduct elemental analysis on the shale core or rock fragment samples to be identified to obtain the geochemical parameters of the strata to be identified;
[0059] (2) Project the geochemical parameters of the strata to be identified onto the bedding development degree identification plate obtained by the aforementioned construction method to obtain the bedding development degree of the strata to be identified.
[0060] Preferably, in step (1), elemental logging technology is used to conduct elemental analysis on the shale core or rock cuttings sample to be identified, and the elemental content data of the strata to be identified is obtained; based on the elemental content data of the strata to be identified, the geochemical parameters of the strata to be identified are obtained.
[0061] Specifically, in this embodiment, after obtaining the bedding development degree identification chart in step S4, during the horizontal well drilling process in the well area, rock cuttings samples or shale cores at different depths are collected, and elemental measurements are carried out (elemental logging technology can be used to obtain elemental logging data) to obtain elemental content data; based on the elemental content data, geochemical parameters at different depths are calculated; the calculated geochemical parameters at different depths are projected onto the bedding development degree identification chart obtained in step S4, and the degree of bedding development can be obtained according to the distribution area of the data points, thereby determining whether the bedding is developed.
[0062] Example 1
[0063] S1: Conduct elemental analysis on shale core or cuttings samples, that is, extract the elemental content data of shale formations from the pilot well of Well X and carry out elemental geochemical analysis of shale formations.
[0064] S11: Continuous drilling and coring were performed on the X-well pilot well to obtain core samples. X-ray fluorescence elemental analysis was conducted on the core samples to obtain elemental content data. In this embodiment, elemental content data refers to the content of each element obtained through X-ray fluorescence spectroscopy analysis, including the mass fractions of more than 20 elements such as Si, Ca, Mg, Fe, K, Na, Al, P, S, Cl, Sr, Ba, Ni, Ti, and V. The mass fractions of each element at different depths are shown in Table 2. It should be noted that due to the large number of element contents obtained in this embodiment, only a portion is shown.
[0065] Table 2 shows the mass fractions of some elements at different depths in Example 1.
[0066] Top depth Bottom depth V Cr Mn Fe Co Ni Cu Zn Ga Mo 4012 4016 492.7821 92.7439 0.0386 0.4495 0 7.032 20.5519 34.2223 5.5929 0.2203 4016 4020 352.3737 80.8712 0.0268 2.0371 0 0 19.135 31.6463 4.0178 0.22 4020 4024 348.9232 107.821 0.0332 2.3537 0 21.8843 19.4203 30.37 3.9771 0.2163 4024 4028 417.7813 90.4103 0.0339 0.4383 0 11.6467 20.21 39.6295 6.8422 0.2405 4028 4032 419.4497 89.3801 0.0328 0.3606 0 13.6632 20.424 35.6611 6.1904 0.2401 4032 4036 399.9601 83.1649 0.0298 2.113 0 5.2094 19.563 27.0282 4.5881 0.2275 4036 4040 409.3257 87.6328 0.0315 2.1975 0 6.9545 20.0501 27.6083 4.8869 0.2357 4040 4044 335.1591 85.174 0.0262 2.0298 0 6.1401 19.1104 23.872 3.9364 0.2173 4044 4048 331.519 98.4412 0.0295 2.1804 0 12.1896 18.98 20.9712 3.7055 0.2171 4048 4052 347.141 88.8337 0.0278 1.9831 0 6.6443 19.2334 26.1927 3.4611 0.2095 4052 4056 347.8994 150.8325 0.0475 0.2516 0 66.0146 23.2849 22.9206 3.3118 0.2224 4056 4060 454.7509 90.9169 0.0344 2.4532 0 10.9487 19.686 37.448 4.2894 0.2392
[0067] S12: Based on elemental content data, the geochemical parameters of the strata are calculated. Specifically, in this embodiment, the geochemical parameters include paleoreducibility (V / Cr), paleoreducibility (V / (V+Ni)), paleosalinity (Sr / Ba), paleowater depth, paleosource (Si), and paleoclimate index. Therefore, this embodiment calculates paleoreducibility (V / Cr), paleoreducibility (V / (V+Ni), paleosalinity (Sr / Ba), paleowater depth, paleosource (Si), and paleoclimate index. The calculation methods and representative meanings of each parameter are shown in Table 1.
[0068] It should be noted that in this embodiment, only "paleoreducibility (V / Cr), paleoreducibility (V / V+Ni), paleosalinity (Sr / Ba), paleowater depth, paleowater depth, sedimentation rate, paleosource, and paleoclimate index" were selected from the parameters "paleoreducibility, chemical weathering intensity, paleosalinity, paleowater depth, sedimentation rate, paleosource, and paleoclimate index." This selection is based on the calculation results of specific geochemical parameters. For example, if the calculated result of a certain geochemical parameter significantly deviates from the normal value, it will not be selected. Those skilled in the art know that the mass fraction of each element in the strata has a normal range, and therefore, its corresponding geochemical parameters also have a normal range (as shown in Table 1). When the calculated result of a certain geochemical parameter significantly deviates from this normal range, it means that the geochemical parameter cannot be used. For example, if the paleoclimate index is greater than 1, or even generally as high as 2-3, then as can be seen from Table 1, the paleoclimate index cannot be used. There are many reasons for significant deviations from normal values. It may be due to the small element logging instrument measuring rock cuttings contaminated by drilling fluid, resulting in inaccurate measurement results for one or more elements. It may also be due to other factors affecting the local formation deposition process, leading to abnormal content of one or more elements.
[0069] The paleoreducing ratio V / Cr, paleoreducing ratio V / V+Ni, paleowater depth, paleosource Si, and paleoclimate index calculated in this embodiment are shown in Table 3.
[0070] Table 3 shows the paleoreducible V / Cr, paleoreducible V / V+Ni, paleowater depth, paleosource Si, and paleoclimate index calculated in Example 1.
[0071]
[0072] S2: Core observation was conducted on the shale core of the X well pilot hole to determine the degree of bedding development. Specifically, the degree of bedding development was determined for the shale core of the X well pilot hole through direct observation and microscopic observation. The degree of bedding development in this embodiment is shown in Table 3.
[0073] S3: Based on the geochemical parameters of the strata in step S1 and the degree of bedding development in step S2, determine the geochemical parameters that are strongly correlated with the degree of bedding development. Using the geochemical parameters of the strata in step S1 and the degree of bedding development in step S2, construct a columnar section (e.g., Figure 2 As shown, the values of geochemical parameters and the degree of bedding development within the same depth segment are compared. If the value of a certain geochemical parameter and the degree of bedding development are strongly correlated within the same depth segment, then that geochemical parameter is a geochemical parameter strongly correlated with the degree of bedding development; if the value of a certain geochemical parameter and the degree of bedding development are weakly correlated within the same depth segment, then that geochemical parameter is not a geochemical parameter strongly correlated with the degree of bedding development.
[0074] Specifically, in this embodiment, taking the comparison between provenance Si and bedding development as an example, the mass fraction of provenance Si is relatively low in the depth range of layered shale with high bedding development. As the bedding development transitions to the depth range of massive shale, the mass fraction of provenance Si increases significantly, and this trend remains consistent across most depth ranges, indicating a strong correlation between provenance Si and bedding development. Similarly, the correlations between paleoreducibility V / Cr, paleoreducibility V / V+Ni, paleowater depth, and paleoclimate index and bedding development were determined sequentially. Ultimately, paleowater depth, provenance Si, and paleoclimate index were found to be strongly correlated with bedding development.
[0075] S4: Based on the geochemical parameters strongly correlated with the degree of bedding development in step S3, a bedding development identification map is obtained. Specifically, geochemical parameters strongly correlated with the degree of bedding development (paleowater depth, paleosource Si, paleoclimate index) are selected, and cross-plots are established in pairs. In this embodiment, cross-plots of paleowater depth-paleosource, paleowater depth-paleoclimate index, and paleosource-paleoclimate index are established respectively (e.g., Figures 3-5 ).by Figure 3 Provided as an example, Figure 3 The CCP includes 20 intersection points, each consisting of two data points: the intersection of paleowater depth and paleoclimate index at a well depth of 4013m, the intersection of paleowater depth and paleoclimate index at a well depth of 4065m, etc., which will not be elaborated here.
[0076] Select intersection maps with distinct boundaries and distribution areas of different bedding development levels as bedding development level identification maps. Still using... Figure 3 Provided as an example, by Figure 3 The paleowater depth-climate index crossplot shows that the data points for layered shale and massive shale are clearly not distributed in the same area. More specifically, the paleowater depth of layered shale is <0.35 and the climate index is <0.53, while that of massive shale is >0.35 and the climate index is >0.53. It should be noted that the boundaries between the areas containing the data points for layered shale and massive shale need to be determined and drawn manually. Similarly, Figure 4 Paleolithic-climate index cross plot and Figure 5 In the paleosource-paleodepth intersection map, the data points for layered shale and massive shale are clearly not distributed in the same area, and the boundaries are obvious.
[0077] analyze Figures 3-5It can be seen that the elemental geochemical parameters of samples with different bedding development levels are clearly zoned and have distinct boundaries in the three cross plots. Only 2 out of 20 data points do not conform to the regional boundaries. Therefore, the consistency rate of the three cross plots is 90%. The paleowater depth-paleoclimate index cross plot, the paleomaterial provenance-paleoclimate index cross plot, and the paleomaterial provenance-paleowater depth cross plot can all be used as maps for identifying the degree of bedding development.
[0078] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0079] In the description of this invention, unless otherwise stated, the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0080] The above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the technical solutions described in the specific embodiments of the present invention. Therefore, the foregoing description is only a preferred option and is not restrictive.
Claims
1. A method for constructing a shale oil formation bedding development degree identification chart, characterized in that, The method comprises the following steps: S1: element analysis is performed on a shale core or a shale cutting sample to obtain geochemical parameters of the formation; S2: core observation is performed on the shale core or the shale cutting sample to obtain the bedding development degree of the formation; S3: based on the geochemical parameters and the bedding development degree, geochemical parameters with strong correlation with the bedding development degree are obtained; S4: based on the geochemical parameters with strong correlation with the bedding development degree, a bedding development degree identification chart is obtained.
2. The method of claim 1, wherein, In step S1, S11: element analysis is performed on a shale core or a shale cutting sample by using element logging technology to obtain element content data; S12: based on the element content data, geochemical parameters of the formation are obtained.
3. The method of claim 1, wherein, In step S1, The geochemical parameters include, but are not limited to, at least one of paleo-reduction, chemical weathering intensity, paleo-salinity, paleo-water depth, sedimentation rate, paleo-provenance, and paleo-climate index.
4. The method of claim 1, wherein, In step S2, The core observation includes at least one of direct observation and microscopic observation.
5. The method of claim 1, wherein, In step S2, The bedding development degree includes massive shale, laminated shale, and bedded shale.
6. The method of claim 1, wherein, In step S3, S31: a column chart is established based on the geochemical parameters, the bedding development degree, and the depth; S32: the geochemical parameters and the bedding development degree in the same depth section in the column chart are compared to obtain geochemical parameters with strong correlation with the bedding development degree.
7. The method of claim 1, wherein, In step S4, S41: the geochemical parameters with strong correlation with the bedding development degree are respectively and pairwise established into cross-plot charts; S42: cross-plot charts with obvious bedding development degree distribution area and boundary are screened out to obtain a bedding development degree identification chart.
8. The method of claim 7, wherein, In step S42, Cross-plot charts with obvious bedding development degree distribution area and boundary and a coincidence rate of no less than 85% are screened out to obtain a bedding development degree identification chart.
9. A method of identifying the degree of shale oil formation stratigraphic layering, characterized by, The method comprises the following steps: (1) element analysis is performed on a shale core or a shale cutting sample to obtain geochemical parameters of the to-be-identified formation; (2) the geochemical parameters of the to-be-identified formation are plotted into the bedding development degree identification chart obtained by the construction method in any one of claims 1-8 to obtain the bedding development degree of the to-be-identified formation.
10. The identification method according to claim 9, characterized in that, In step (1), element analysis is performed on a shale core or a shale cutting sample by using element logging technology to obtain element content data of the to-be-identified formation; based on the element content data of the to-be-identified formation, geochemical parameters of the to-be-identified formation are obtained.