Method and device for determining interlayer distribution characteristics in oil field block level layer

Abstract

The invention relates to the technical field of oil field development, in particular to a method and a device for determining interlayer distribution characteristics in an oil field block level layer. The method comprises the following steps: determining interlayer development data according to the physical property of a closed coring well and a comprehensive washing histogram; the interlayer data are input into the three-level layering boundary data so that the interlayer data can be displayed on the sedimentary facies belt graph, an interlayer space distribution form is drawn on the sedimentary facies belt graph through a sedimentary microfacies description method, a sedimentary unit interlayer plane distribution graph is obtained, and interlayer plane distribution characteristics are determined according to the sedimentary unit interlayer plane distribution graph; determining the saturation of remaining oil near interlayers at different development positions of the work area according to the physical property of the closed coring well; and determining interlayer distribution characteristics according to the interlayer development data, the interlayer plane distribution characteristics and the remaining oil saturation. The invention aims to solve the problem that the potential tapping difficulty of remaining oil in an interlayer in the development process is high because the existing interlayer identification is mainly carried out according to logging information, the identification result is not representative, and the interlayer space distribution rule cannot be determined.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield development, and in particular to a method and device for determining interlayer distribution characteristics within a block-level layer of an oilfield. Background Art

[0002] Oilfield development practice demonstrates that in the late stages of development, with high water cuts, as the target deteriorates, the distribution of remaining oil becomes increasingly fragmented, making it increasingly difficult to tap its potential. In particular, interlayered residual oil with a certain degree of permeability barrier has become a key target for water / polymer flooding development. Therefore, to effectively tap this interlayered residual oil, calculation methods for the distribution characteristics of interlayers at the oilfield block level are crucial. Existing research on interlayer characteristics primarily focuses on interlayer genesis, lithology, density, and distribution frequency. Most of this research is based on manual identification and analysis of logging data from a small number of cored wells, making it unrepresentative. In particular, limited research has examined the spatial distribution patterns of interlayers in different reservoirs, making tapping the potential of interlayered residual oil during water / polymer flooding development in oilfields more difficult. Therefore, accurately determining the distribution characteristics of interlayers at the oilfield block level has become an urgent challenge. Summary of the Invention

[0003] The present invention proposes a method and device for determining the distribution characteristics of interlayers at the block level in an oilfield, in order to solve the problem that interlayer identification is currently mainly based on manual identification based on well logging data, the identification results are not representative, and the spatial distribution pattern of interlayers cannot be clearly defined, resulting in great difficulty in tapping the potential of remaining oil in interlayers during development.

[0004] According to one aspect of the present invention, a method for determining interlayer distribution characteristics within an oilfield block level layer is provided, comprising:

[0005] Obtain basic static data within the target oilfield block, including at least: physical properties of sealed core wells, comprehensive water wash histogram, three-level stratification boundary data, sedimentary facies map and interlayer data;

[0006] Determining the interlayer development data based on the physical properties of the sealed coring well and the comprehensive water washing histogram;

[0007] Inputting the interlayer data into the three-level stratification boundary data, so that the interlayer data is displayed on the sedimentary facies belt map corresponding to each layer, and using the sedimentary microfacies characterization method, drawing the interlayer spatial distribution morphology along the river channel direction on the sedimentary facies belt map to obtain the sedimentary unit interlayer plane distribution map;

[0008] Determining interlayer plane distribution characteristics according to the interlayer plane distribution diagram of the deposition unit;

[0009] Determine the remaining oil saturation near interlayers at different development locations in the work area based on the physical properties of the sealed coring wells;

[0010] The interlayer distribution characteristics are determined based on the interlayer development data, interlayer plane distribution characteristics and remaining oil saturation.

[0011] Preferably, the interlayer development data at least include: interlayer development location, distribution frequency, distribution density, lithology, oil content, interlayer physical properties and flow blocking capacity.

[0012] Preferably, before inputting the interlayer data into the three-level stratification boundary data, each oil layer in each sedimentary unit in the three-level stratification boundary data is further divided into a plurality of layers, the method comprising:

[0013] If the effective thickness of the oil layer is less than a predetermined value, the oil layer is divided into two sections. If the effective thickness of the oil layer is greater than or equal to the predetermined value, the oil layer is divided into three sections.

[0014] Preferably, the interlayer plane distribution characteristics include at least: interlayer development width, extension distance, interlayer development ratio in different parts of the oil layer, and interlayer number ratio.

[0015] Preferably, the interlayer development ratio is calculated by formula (1);

[0016]

[0017] The ratio of the number of interlayers is calculated using formula (2);

[0018]

[0019] Where C 沉积单元i夹层发育比例 is the development ratio of interlayer in sedimentary unit i, %; n 沉积单元i河道钻遇夹层井数 is the number of wells with intercalations in sedimentary unit i that encountered a river channel, n 沉积单元i钻遇河道总井数 is the total number of wells drilling into the river channel in sedimentary unit i, D 沉积单元i夹层个数比例 is the ratio of intercalation number in single well of sedimentary unit i, number / well; m 沉积单元i河道内夹层数 is the total number of interlayers encountered in the channel of sedimentary unit i,

[0020] Preferably, before determining the remaining oil saturation near interlayers at different development positions in the work area based on the physical properties of the sealed coring well, the method further includes:

[0021] According to the interlayer plane distribution diagram of the sedimentary unit, the lateral accumulation interlayer is identified, and the interlayer dip angle corresponding to the lateral accumulation interlayer is determined.

[0022] Preferably, the method for identifying lateral accumulation interlayers comprises:

[0023] An abandoned river channel is identified on the planar distribution diagram of the interlayer of the sedimentary unit, and the interlayer in the abandoned river channel is the lateral accumulation interlayer.

[0024] Preferably, the method for determining the interlayer dip angle corresponding to the lateral accumulation interlayer comprises:

[0025] Use formula (3) to calculate the intercalation angle corresponding to the lateral accumulation intercalation;

[0026] α=H1 / H2 (3);

[0027] Where H1 is the distance between the two wells containing the same lateral accumulation interlayer, and H2 is the difference in vertical depth of the same lateral accumulation interlayer between the two wells.

[0028] According to one aspect of the present invention, a device for determining interlayer distribution characteristics within an oilfield block level layer is provided, comprising:

[0029] An acquisition unit is used to acquire basic static data within the target oilfield block, including at least: physical properties of sealed core wells, comprehensive water washing histogram, three-level stratification boundary data, sedimentary facies map and interlayer data;

[0030] an interlayer development data determining unit, configured to determine the interlayer development data according to the physical properties of the sealed coring well and a comprehensive water-washing histogram;

[0031] an interlayer characterization unit, configured to input the interlayer data into the three-level stratification boundary data, so that the interlayer data is displayed on a sedimentary facies belt map corresponding to each layer, and to draw the spatial distribution morphology of the interlayer along the river channel direction on the sedimentary facies belt map using a sedimentary microfacies characterization method to obtain a planar distribution map of the interlayer of the sedimentary unit;

[0032] an interlayer distribution feature determination unit, configured to determine an interlayer plane distribution feature according to the interlayer plane distribution diagram of the deposition unit;

[0033] A remaining oil saturation determination unit is used to determine the remaining oil saturation near interlayers at different development positions in the work area based on the physical properties of the sealed coring well;

[0034] The interlayer distribution characteristic determination unit is used to determine the interlayer distribution characteristics according to the interlayer development data, the interlayer plane distribution characteristics and the remaining oil saturation.

[0035] The present invention has at least the following beneficial effects:

[0036] The present invention proposes a method and device for determining the distribution characteristics of interlayers at the block level in an oilfield. By combining interlayer data with a sedimentary facies map, the planar distribution characteristics of the interlayers are obtained. Combined with the development data of the interlayers and the remaining oil saturation data near the interlayers, the interlayer distribution characteristics are determined. This achieves a qualitative description and quantitative determination of the longitudinal and planar distribution characteristics of the interlayers. The identification results are highly accurate, providing a reliable basis for subsequent residual oil potential development. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present invention and, together with the specification, are used to explain the technical solutions of the present invention.

[0038] Figure 1 A flow chart showing a method for determining interlayer distribution characteristics within an oilfield block level layer according to an embodiment of the present invention;

[0039] Figure 2 A schematic diagram illustrating a process for depicting the spatial distribution of an inner interlayer according to an embodiment of the present invention is shown;

[0040] Figure 3 Shows the upper and lower interlayer stacking distribution diagram of the PII8+9 unit according to an embodiment of the present invention;

[0041] Figure 4 1. A plan view showing the side accumulation layer of the PII8+9 unit according to an embodiment of the present invention is shown;

[0042] Figure 5 A diagram showing the core water washing condition near the interlayer of a coring well according to an embodiment of the present invention is shown;

[0043] Figure 6 A diagram showing the oil saturation of the core at the interlayer portion of a coring well according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0044] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0045] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0046] The term "and / or" herein simply describes an association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can represent the existence of three situations: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" herein refers to any combination of at least two of any one or more of a plurality of items. For example, "at least one of A, B, and C" can represent any one or more elements selected from the set consisting of A, B, and C.

[0047] In addition, numerous specific details are provided in the following detailed description to better illustrate the present invention. Those skilled in the art will appreciate that the present invention may be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of the present invention.

[0048] Figure 1 A flow chart showing a method for determining interlayer distribution characteristics within an oilfield block level layer according to an embodiment of the present invention; Figure 2 A schematic diagram illustrating a process for depicting the spatial distribution of an inner interlayer according to an embodiment of the present invention is shown; Figure 3 Shows the upper and lower interlayer stacking distribution diagram of the PII8+9 unit according to an embodiment of the present invention; Figure 4 1. A plan view showing the side accumulation layer of the PII8+9 unit according to an embodiment of the present invention is shown; Figure 5 A diagram showing the core water washing condition near the interlayer of a coring well according to an embodiment of the present invention is shown; Figure 6 The oil saturation diagram of the core in the interlayer of the coring well according to the embodiment of the present invention is shown. Figure 1-6 As shown, a method for determining the distribution characteristics of interlayers in oilfield block layers comprises: step S01: obtaining basic static data in the target oilfield block, which at least includes: physical properties of sealed coring wells, comprehensive water washing histogram, three-level stratification boundary data, sedimentary facies map and interlayer data; step S02: determining the interlayer development data according to the physical properties of the sealed coring wells and the comprehensive water washing histogram; step S03: inputting the interlayer data into the three-level stratification boundary data so that the interlayer data is displayed in each layer pair. On the corresponding sedimentary facies belt map, the spatial distribution morphology of the interlayer is drawn along the river channel direction on the sedimentary facies belt map using the sedimentary microfacies characterization method to obtain the sedimentary unit interlayer plane distribution map; step S04: according to the sedimentary unit interlayer plane distribution map, the interlayer plane distribution characteristics are determined; step S05: according to the physical properties of the closed coring well, the remaining oil saturation near the interlayer at different development positions in the work area is determined; step S06: according to the interlayer development data, the interlayer plane distribution characteristics and the remaining oil saturation, the interlayer distribution characteristics are determined.

[0049] The method for determining the distribution characteristics of interlayers within an oilfield block provided by an embodiment of the present invention specifically includes the following steps:

[0050] Step S01: Obtain basic static data within the target oilfield block, including at least: physical properties of sealed core wells, comprehensive water washing histogram, three-level stratification boundary data, sedimentary facies map and interlayer data.

[0051] In an embodiment of the present invention, the basic static data of the target oil field and block is checked to verify the validity of the data, and the method includes:

[0052] Extract element data from the three-level stratification boundary data, sedimentary facies belt map and interlayer data, including at least the injection and production well number, sedimentary unit name, sedimentary facies category of each well in each sedimentary unit, stratification boundary of each well in each sedimentary unit, interlayer thickness and effective thickness, and the position of interlayer and stratification boundary; based on the above element data, check and determine whether the distribution position of the interlayer of the sedimentary unit is within the three-level stratification boundary of the same sedimentary unit, and whether the sedimentary unit category and the three-level stratification boundary of the sedimentary unit of each well are consistent with the sedimentary unit reservoir data. If not, the data is invalid and needs to be deleted or modified to valid data.

[0053] Step S02: Determine the interlayer development data according to the physical properties of the sealed coring well and the comprehensive water washing histogram.

[0054] In the present invention, the interlayer development data at least include: interlayer development location, distribution frequency, distribution density, lithology, oil content, interlayer physical properties and flow blocking capacity.

[0055] In an embodiment of the present invention, through the physical properties of the sealed coring wells and the comprehensive water-washed histogram data within the target oil field block over the years, the interlayer development data such as the interlayer development position, distribution frequency, distribution density, lithology, oil content, as well as the thickness and number data of the interlayer can be analyzed to obtain the interlayer development data, thereby determining the interlayer physical properties and flow blocking capacity of the target oil field block.

[0056] The method for obtaining interlayer development data by analyzing the physical properties of closed coring wells and comprehensive water-washing histogram data is as follows: the corresponding sample number of the interlayer and the development position, thickness, lithology, and oil content data of the interlayer are determined by the comprehensive water-washing histogram of the coring well; the physical property parameters such as porosity and permeability of the interlayer can be found by the interlayer sample number in the physical property data of the coring well; and the development position, thickness, lithology, and oil content of the interlayer determined by the water-washing histogram are supplemented to the corresponding interlayer physical property data to form a basic table of interlayer statistical data.

[0057] Step S03: Input the interlayer data into the three-level stratification boundary data, so that the interlayer data is displayed on the sedimentary facies belt map corresponding to each layer, and use the sedimentary microfacies characterization method to draw the interlayer spatial distribution morphology along the river channel direction on the sedimentary facies belt map to obtain the sedimentary unit interlayer plane distribution map.

[0058] In the present invention, before the interlayer data is input into the three-level stratification boundary data, each oil layer in each sedimentary unit in the three-level stratification boundary data is further divided into several layers. The method includes: if the effective thickness of the oil layer is less than a predetermined value, the oil layer is divided into two sections; if the effective thickness of the oil layer is greater than or equal to the predetermined value, the oil layer is divided into three sections.

[0059] In the embodiment of the present invention, an equal division method is adopted to establish new three-level stratified boundary data of the GPTMAP work area of the target oilfield block, and the new boundaries are named as the upper part, lower part, or upper part, middle part, and lower part of a sedimentary unit;

[0060] The three-level boundary data for the target GPTMAP work area was reprocessed. Each sedimentary unit within the target oilfield block was divided equally based on its top and bottom reservoir depths. If the reservoir thickness was small (i.e., its effective thickness was less than a predetermined value), it was split into upper and lower reservoir sections. If the effective reservoir thickness was greater than the predetermined value, it was split into upper, middle, and lower reservoir sections. This equalization of the reservoir section allows for a more detailed characterization of the planar distribution of interlayers within the reservoir. The predetermined value was 2 meters.

[0061] When the oil layer is divided into two parts, the top depths of the upper and lower parts of the oil layer are as shown in the following equations (4) and (5):

[0062] H 上部顶深i =H 顶深i (4)

[0063]

[0064] Where: H 上部顶深i is the top depth of the oil layer after the sedimentary unit i is evenly divided, m; H 顶深i is the top depth of the oil layer before the sedimentary unit i is evenly divided, m; H 下部顶深i is the top depth of the lower part of the oil layer after the sedimentary unit i is evenly divided, m; H 底深i is the depth of the oil layer bottom before sedimentary unit i is evenly divided, m.

[0065] Input the interlayer data into the new three-level stratification boundary data after equalization, so that the interlayer data is displayed on the sedimentary facies belt map corresponding to each equalized layer. Specifically, use GPTMAP software to display the interlayer thickness data of the target block in the new three-level stratification boundary data category after equalization. The process is as follows: create a new horizon in GPTMAP software, import the new three-level stratification boundary data after equalization, and simultaneously import the interlayer data into the sandstone category, using the sandstone data to split the layer data. The interlayer data will now be displayed in the three-level stratification boundary data category.

[0066] The specific operation process in the software is:

[0067] The first step is to define the layers. In the GPTMAP software start menu, select Define Layers to import the newly divided sedimentary units.

[0068] The second step is to import the new three-level stratification boundary data: import the newly divided new three-level stratification boundary data into the stratification boundary classification under the data directory;

[0069] The third step is to import interlayer: import the sorted interlayer data into the sandstone classification under the data directory; because the software does not originally have the function of displaying interlayer data, import the interlayer data into the original sandstone classification data entry, and use the interlayer thickness data to replace the first and second type sandstone thickness data or effective thickness data;

[0070] The fourth step is to split the layered data: In the data menu - data calculation - calculation method - user-specific customization and others, choose to use sandstone data to split the layered data. At this time, the imported interlayer data will be displayed in the new three-level layered boundary data category.

[0071] After the above operations are completed, the interlayer data of each layer will be displayed on the sedimentary facies map corresponding to the new three-level stratification boundary data.

[0072] The interlayer data information corresponding to the upper and lower parts, or the upper, middle and lower parts of the equally divided oil layer are marked on the corresponding sedimentary facies belt map. According to the principle that the distribution of interlayers within the layer is similar to the distribution morphology of river channel sand bodies, the sedimentary microfacies characterization method is used to draw the plane distribution map of interlayers in each sedimentary unit. The spatial distribution law of interlayers within the river channel is intuitively displayed on the sedimentary facies belt map, realizing the plane tracking of interlayers in the same layer.

[0073] When drawing in the GPTMAP software, first establish the filling mode of the interlayer in the settings-sedimentary phase, then establish an information identification layer on the original sedimentary phase belt map, and display the interlayer thickness data near the well position of the sedimentary phase belt map in the form of generating a base map. Then, draw the spatial distribution form of the interlayer on the sedimentary phase belt map along the river channel direction. After the drawing is completed, the plane distribution map of the sedimentary unit interlayer corresponding to each layer is obtained.

[0074] Step S04: determining interlayer plane distribution characteristics according to the interlayer plane distribution diagram of the deposition unit.

[0075] In the present invention, the interlayer plane distribution characteristics include at least: interlayer development width, extension distance, interlayer development ratio in different parts of the oil layer, and interlayer number ratio.

[0076] In the present invention, the interlayer development ratio is calculated by formula (1);

[0077]

[0078] The ratio of the number of interlayers is calculated using formula (2);

[0079]

[0080] Where C 沉积单元i夹层发育比例 is the development ratio of interlayer in sedimentary unit i, %; n 沉积单元i河道钻遇夹层井数 is the number of wells with intercalations in sedimentary unit i that encountered a river channel, n沉积单元i钻遇河道总井数 is the total number of wells drilling into the river channel in sedimentary unit i, D 沉积单元i夹层个数比例 is the ratio of intercalation number in single well of sedimentary unit i, number / well; m 沉积单元i河道内夹层数 is the total number of interlayers encountered in the channel of sedimentary unit i,

[0081] In an embodiment of the present invention, according to the planar distribution pattern of interlayers in the upper and lower parts, or the upper, middle and lower oil layers of each sedimentary unit of the target block obtained in step S03, that is, the planar distribution diagram of the sedimentary unit interlayers, key characterization parameters of the planar distribution characteristics of the interlayers, such as the interlayer development width, extension distance, interlayer development ratio and interlayer number ratio at different parts of different oil layers in the target block, can be determined. The interlayer development width and extension distance can be calculated by comparing with the scale scale to obtain actual values. The calculation formulas for the interlayer development ratio and interlayer number ratio are shown in Formulas (1) and (2).

[0082] Step S05: Determine the remaining oil saturation near interlayers at different development positions in the work area based on the physical properties of the sealed coring well.

[0083] In an embodiment of the present invention, the physical property logging interpretation results of sealed coring wells in the target oilfield block over the years can be used, combined with the interlayer position, lithology, thickness and other data of the comprehensive water washing histogram of the coring wells, as well as the interlayer development data, to statistically determine the remaining oil saturation at different development positions of the interlayer, i.e., near the interlayer, above the interlayer, below the interlayer, or above, middle and below the interlayer, to determine the scale of the interlayer-type remaining oil reserves in the target area, and quantitatively evaluate the influence of the interlayer on the distribution of the remaining oil.

[0084] In the present invention, before determining the remaining oil saturation near interlayers at different development positions in the work area based on the comprehensive water-washed histogram, the method further includes: identifying lateral accumulation interlayers based on the interlayer plane distribution diagram of the sedimentary unit, and determining the interlayer dip angle corresponding to the lateral accumulation interlayers.

[0085] In the present invention, the method for identifying lateral accumulation interlayers comprises: identifying an abandoned river channel on a planar distribution diagram of interlayers in the sedimentary unit, wherein the interlayers in the abandoned river channel are the lateral accumulation interlayers.

[0086] In the present invention, the method for determining the interlayer dip angle corresponding to the lateral accumulation interlayer comprises: calculating the interlayer dip angle corresponding to the lateral accumulation interlayer using formula (3);

[0087] α=H1 / H2 (3);

[0088] Where H1 is the distance between the two wells containing the same lateral accumulation interlayer, and H2 is the difference in vertical depth of the same lateral accumulation interlayer between the two wells.

[0089] In an embodiment of the present invention, an abandoned river channel is first identified on the planar distribution diagram of the interlayers in the sedimentary unit. The interlayers in the abandoned river channel are in a lateral accumulation form, and the planar distribution form of the interlayers is similar to that of the abandoned river channel. The interlayers in the layer are distributed nearly horizontally along the abandoned river channel and have a certain occurrence in the direction perpendicular to the abandoned river channel.

[0090] The study found that the greater the inclination angle of the interlayer, the greater the impact on development. The inclination angle of the lateral interlayer in the abandoned river channel is relatively large, which will have a greater impact on oilfield gas development. Once the lateral interlayer is identified, targeted transformation measures can be taken to tap the potential of the lateral interlayer-obstructed residual oil.

[0091] Step S06: Determine interlayer distribution characteristics based on the interlayer development data, interlayer plane distribution characteristics, and remaining oil saturation.

[0092] In the embodiment of the present invention, the interlayer development data, the interlayer plane distribution characteristics and the remaining oil saturation reflect the distribution characteristics of the interlayer. According to the interlayer distribution characteristics, a strategy for tapping the potential of interlayer type remaining oil is formulated.

[0093] Potential development direction of interlayer residual oil: The interlayer residual oil of positive rhythm oil layer is mainly enriched near the oil well and in the upper part of the interlayer. Therefore, the water polymerization flooding process of positive rhythm oil layer should focus on tapping the potential of the residual oil in the upper part of the interlayer and near the oil well; the interlayer residual oil of negative rhythm oil layer is mainly enriched near the oil well and in the lower part of the interlayer. Therefore, the negative rhythm oil layer should focus on tapping the potential of the residual oil near the oil well and in the lower part of the interlayer.

[0094] Countermeasures for tapping the potential of remaining oil in interlayers: For the vertical interlayer direction, fracturing and plugging measures should be used to tap the potential of obstructed remaining oil; while for the direction along the interlayer, injection parameter adjustment should be the main measure.

[0095] In this embodiment, a typical Class II oil reservoir block in Block A in the northern region of the oil field is used as an example. The block has a five-point areal well pattern with a well spacing of 150 meters and 237 injection and production wells, including 107 injection wells and 130 production wells. The target strata for production are Pu II 7 to Gao I 4+5, with eight sedimentary units. Basic static data for the block is obtained, including: physical properties of sealed core wells collected over the years within the target oil field, comprehensive water wash histograms, well logging interpretation curves, the target block GPTMAP work area, the target block injection and production well numbers, sedimentary unit reservoir data (sedimentary facies map), GPTMAP work area three-level stratification boundary data, the target block GPTMAP work area sedimentary facies map, and an interlayer database.

[0096] Extract element data from sedimentary unit reservoir data, three-level stratification boundary data, sedimentary facies data, and interlayer data. This includes injection and production well numbers, sedimentary unit names, sedimentary facies categories for each well within each sedimentary unit, stratification boundaries for each well within each sedimentary unit, interlayer thickness and effective thickness, and the location of interlayers and stratification boundaries. Verify that the distribution of sedimentary unit interlayers is within the three-level stratification boundaries of the same sedimentary unit, and that the sedimentary unit categories and three-level stratification boundaries of each well are consistent with the sedimentary unit reservoir data to verify the validity of the data.

[0097] Using the physical property data of sealed coring wells combined with a comprehensive water-washed histogram, and based on the intercalation information in the comprehensive water-washed histogram, we obtained data such as the location, distribution frequency, distribution density, thickness, number, lithology, oil content, and physical properties of intercalations within the interlayer. A statistical table of intercalation characteristics in the coring wells was generated. Some of the results are shown in Table 1. A total of 55 intercalations were identified in the coring wells, with a thickness ranging from 0.08 to 0.33 m and an average thickness of 0.16 m. These intercalations were primarily physical and lithologic, with low permeability and strong flow resistance. The lithology was primarily argillaceous siltstone and siltstone, accounting for 73%. In terms of oil content, dry layers, oil spots, and oil-immersion were the main components, accounting for approximately 80%. Intercalation frequency = number of intercalations / effective thickness = 55 / 127 = 0.43 intercalations / m, and intercalation density = intercalation thickness / effective thickness = 8.91 / 127 = 0.07 m / m.

[0098] Table 1: Statistics of intercalation development data of core wells in the northern block of the oil field

[0099]

[0100]

[0101] Using Excel to process the three-level stratification boundary data, formulas (4) and (5) were used to divide the oil layer of each sedimentary unit in the block into two or three sections, named the upper and lower parts or the upper, middle, and lower parts of a sedimentary unit. When the oil layer thickness is small, that is, the average effective thickness of the oil layer is less than 2m, the oil layer is divided into two sections. When the oil layer thickness is large, that is, greater than or equal to 2m, it can also be divided into three sections: upper, middle, and lower. The results of the division are shown in Table 2.

[0102] Table 2: New three-level stratification boundaries of the northern block of the oil field

[0103]

[0104] Use GPTMAP software to display the interlayer data in the three-level stratification boundary data category. The specific operations are:

[0105] The first step is to define the layers. In the start menu, define the layers and import the newly divided sedimentary units.

[0106] The second step is to import the newly divided three-level stratification boundary data: import the newly divided three-level stratification boundary data into the stratification boundary classification under the data directory;

[0107] The third step is to import interlayers: import the sorted interlayer data into the sandstone classification under the data directory; use the depth of the interlayer top to correspond to the bottom depth of the second-class sandstone, and the thickness to correspond to the thickness of the second-class sandstone;

[0108] The fourth step is to split the layered data: In the data menu - data calculation - calculation method - user-specific customization and others, choose to use sandstone data to split the layered data. At this time, the interlayer data will be displayed in the second-level sandstone data under the third-level layer boundary data category.

[0109] The method of drawing sedimentary microfacies is used to draw the spatial distribution of interlayers along the river channel on the sedimentary facies belt map, so that the spatial distribution law of interlayers in the river channel can be intuitively displayed on the sedimentary facies belt map, and the plane tracking of interlayers in the same layer can be achieved. The specific operations in GPTMAP software are as follows:

[0110] Step 1: Establish the filling pattern of the upper and lower interlayers in the setup-deposition phase;

[0111] Step 2: Create an information identification layer on the original phase map to generate a base map to display the interlayer thickness near the well location in the sedimentary phase map. Take P28+9 as an example, open the P28+9 sedimentary phase belt map, create a new information identification layer in the layer management, and then select Plane Map-Base Map-Information Identification, set the layer level to 3, select P28+9 for the layer number, select the layer boundary for the data table, select the thickness of the second-class sandstone, and select any of the 8 directions for the relative position. Select the left side of the relative well location. After clicking OK, the interlayer thickness will be displayed on the left side of the well location in the phase belt map.

[0112] Step 3: Create a sedimentary facies layer according to the sedimentary model and draw an interlayer distribution map. Extend the distance along the provenance direction and cut the provenance direction to a single channel boundary. Add a facies line - Close and select the interlayer type. Select Format - Point Method - Fill - Lower Interlayer Type.

[0113] Use this method to draw the upper and lower interlayer planar layouts of each sedimentary unit. Figure 2 As shown, in Figure 2 In the figure, Figure a is the interlayer thickness marking diagram, Figure b is the interlayer extension depiction diagram, and Figure c is the interlayer plane distribution diagram of the PII8+9 sedimentary unit.

[0114] According to the planar distribution pattern of interlayers in the upper and lower oil layers of each sedimentary unit in the target block obtained in the previous step (interlayer planar distribution diagram), key characterization parameters such as interlayer development width, extension distance, interlayer development ratio in different parts of the oil layer, and interlayer number ratio under different river channel deposition modes are calculated using formulas (1) and (2).

[0115] like Figure 3 The figure shows the superimposed distribution of the interlayer of unit PII8+9 in the northern A block. Figure 3 This block demonstrates low-lying distributary channel deposits. Intercalations are well-developed both above and below the wide channel, with a lateral width of approximately 150-300 meters and a vertical extension of approximately 600-800 meters. Intercalations are also well-developed above and below the narrow channel, with a width comparable to the channel itself. Intercalations are stably distributed, extending an average of 3-5 well spacings, allowing for traceability and comparison. Table 3 shows the statistical characteristics of intercalation parameters within the channel sand bodies of Block A in the north. Intercalation rates within the channel in Block A range from 40% to 60%, with a per-well ratio of 1.5-2.0 intercalations. The proportion of upper intercalations is higher than that of lower intercalations.

[0116] Table 3: Characteristics of interlayer parameters in the northern A block

[0117]

[0118] Identify lateral accumulation interlayers on the interlayer plane distribution map of the sedimentary unit, and calculate the inclination angle of the lateral accumulation interlayers. First, identify the abandoned river channel on the interlayer plane distribution map of the sedimentary unit. The interlayers in the abandoned river channel are in the form of lateral accumulation. The interlayer plane distribution form is similar to that of the abandoned river channel. The interlayers are nearly horizontally distributed along the abandoned river channel, and have a certain occurrence perpendicular to the abandoned river channel. Lateral accumulation interlayers are distributed in meandering rivers and high and low bend diversion channels. PII8+9 unit identifies a single river channel and an abandoned river channel, and the interlayer plane is distributed in a single river channel; Figure 4 The figure shows the identified lateral accumulation intercalation. The intercalation within the abandoned channel exhibits a lateral accumulation pattern, with a planar distribution similar to that of the abandoned channel. The intercalation lies nearly horizontally along the abandoned channel, with a definite occurrence perpendicular to the abandoned channel. The intercalation angle (intercalation dip) is α = H1 / H2 = 3.1°. H1 is the distance between the two wells containing the same intercalation, and H2 is the difference in vertical depth between the two wells.

[0119] The oil saturation of the remaining oil near the interlayer is calculated based on the comprehensive water washing histogram, and the distribution pattern of the remaining oil is determined. The calculation results are shown in Table 4. The difference in the distribution of the remaining oil between the upper and lower parts of the interlayer is compared using the comprehensive water washing data (comprehensive water washing histogram). Figure 6 The figure shows the oil saturation of the core in the interlayer of the core well in Block A. Figure 6It can be seen that although the water flooding development time of the second type oil layer in the oil field is relatively long, the oil saturation of the remaining oil near the interlayer is still relatively high at about 50%. Compared with the adjacent core, the oil saturation near the interlayer is 11.5% higher than that of the adjacent core.

[0120] Table 4: Remaining oil saturation and water washing conditions near the interlayer in the cored wells of Block A in the northern part of the oilfield

[0121]

[0122] like Figure 5 The following is a diagram showing the core water washing condition near the interlayer of the coring well in Block A. Figure 5 It can be seen that due to the shielding effect of interlayers on the remaining oil, the rock samples near the interlayers are weak and the proportion of unwashed samples is as high as 37%, and the remaining oil is enriched, which is an important potential site.

[0123] Based on the interlayer development data, interlayer planar distribution characteristics, lateral accumulation of interlayers, and remaining oil saturation obtained above, the interlayer distribution and remaining oil control are determined. Polymer flooding development in oil fields has entered a phase of precise control and deep potential development, requiring personalized design of injection parameters and the timing of adjustment measures. Based on numerical simulations investigating the impact of interlayer distribution characteristics on polymer flooding effectiveness, targeted efforts are being made to tap the potential of interlayer-type remaining oil. For positive-rhythm reservoirs, interlayer-type remaining oil is primarily concentrated near the wells and above the interlayers. Therefore, water-polymer flooding in positive-rhythm reservoirs should focus on tapping the remaining oil above the interlayers and near the wells. For negative-rhythm reservoirs, interlayer-type remaining oil is primarily concentrated near the wells and below the interlayers. Therefore, tapping the remaining oil near the wells and below the interlayers should be the focus in negative-rhythm reservoirs. The strategy for tapping the potential of interlayer remaining oil is to use fracturing and gap filling measures perpendicular to the interlayers to tap the potential of obstructed remaining oil; while for those along the interlayers, injection parameter adjustment is the primary approach.

[0124] It can be understood that the above-mentioned various method embodiments mentioned in the present invention can be combined with each other to form combined embodiments without violating the principle logic. Due to space limitations, the present invention will not elaborate on them.

[0125] The execution subject of the method for determining the distribution characteristics of interlayers within an oilfield block-level layer may be an apparatus for determining the distribution characteristics of interlayers within an oilfield block-level layer. For example, the method for determining the distribution characteristics of interlayers within an oilfield block-level layer may be executed by a terminal device, a server, or other processing device, wherein the terminal device may be a user equipment (UE), a mobile device, a user terminal, a terminal, a cellular phone, a cordless phone, a personal digital assistant (PDA), a handheld device, a computing device, an in-vehicle device, a wearable device, etc. In some possible implementations, the method for determining the distribution characteristics of interlayers within an oilfield block-level layer may be implemented by a processor calling computer-readable instructions stored in a memory.

[0126] Those skilled in the art will understand that in the above-mentioned method of the specific implementation method, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0127] The present invention also proposes a device for determining the distribution characteristics of interlayers in oilfield block-level layers, comprising: an acquisition unit for acquiring basic static data in the target oilfield block, which at least includes: physical properties of sealed coring wells, comprehensive water-washing histograms, three-level stratification boundary data, sedimentary facies maps, and interlayer data; an interlayer development data determination unit for determining the interlayer development data based on the physical properties of the sealed coring wells and the comprehensive water-washing histograms; an interlayer characterization unit for inputting the interlayer data into the three-level stratification boundary data so that the interlayer data is displayed in the sedimentary facies corresponding to each layer. On the sedimentary facies belt map, the sedimentary microfacies characterization method is used to draw the spatial distribution morphology of the interlayer along the river channel direction on the sedimentary facies belt map to obtain the interlayer plane distribution map of the sedimentary unit; the interlayer distribution feature determination unit is used to determine the interlayer plane distribution features based on the interlayer plane distribution map of the sedimentary unit; the remaining oil saturation determination unit is used to determine the remaining oil saturation near the interlayer at different development positions in the work area based on the physical properties of the closed coring well; the interlayer distribution feature determination unit is used to determine the interlayer distribution features based on the interlayer development data, interlayer plane distribution features and remaining oil saturation.

[0128] In some embodiments, the functions or modules included in the device provided by the embodiment of the present invention can be used to execute the method described in the above method embodiment. Its specific implementation can refer to the description of the above method embodiment. For the sake of brevity, it will not be repeated here.

[0129] Most existing methods for studying the distribution characteristics of interlayers are based on statistical analysis of data from a small number of coring wells. They can only provide a rough understanding of the longitudinal development characteristics of interlayers, such as development frequency and density, but have a poor understanding of the planar distribution patterns of interlayers at different locations in the target block's oil layer. The method of the present invention can achieve qualitative description and quantitative calculation of the longitudinal and planar distribution characteristics of interlayers at the oil field block level and in different locations in the oil layer. It can be used to objectively evaluate the distribution characteristics of interlayers within the oil field block level and the scale of interlayer-type remaining oil reserves, solving the problems of the difficulty in tapping the potential of interlayer-type remaining oil. In particular, it breaks through the technical bottleneck of the lack of objective evaluation of the planar distribution patterns of interlayers in different locations in the oil layer and the large errors in manual identification of interlayers. The method provided by the present invention can not only obtain the longitudinal distribution characteristics of interlayers, but also determine the planar distribution patterns of interlayers in all target layers of the target block. With the help of this method, not only can the scale of interlayer-type remaining oil reserves in the oil layer be clarified, but also guidance can be provided for the tapping direction and potential tapping strategies of interlayer-type remaining oil in the water / polymer flooding development process.

[0130] While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for determining the distribution characteristics of interlayers within an oilfield block, characterized in that: include: Obtain basic static data within the target oilfield block, including at least: physical properties of sealed core wells, comprehensive water wash histogram, three-level stratification boundary data, sedimentary facies map and interlayer data; Determining the interlayer development data based on the physical properties of the sealed coring well and the comprehensive water washing histogram; Inputting the interlayer data into the three-level stratification boundary data, so that the interlayer data is displayed on the sedimentary facies belt map corresponding to each layer, and using the sedimentary microfacies characterization method, drawing the interlayer spatial distribution morphology along the river channel direction on the sedimentary facies belt map to obtain the sedimentary unit interlayer plane distribution map; Determining interlayer plane distribution characteristics according to the interlayer plane distribution diagram of the deposition unit; Determine the remaining oil saturation near interlayers at different development locations in the work area based on the physical properties of the sealed coring wells; The interlayer distribution characteristics are determined based on the interlayer development data, interlayer plane distribution characteristics and remaining oil saturation.

2. The method for determining the distribution characteristics of interlayers within an oilfield block according to claim 1, characterized in that: The interlayer development data at least include: interlayer development location, distribution frequency, distribution density, lithology, oil content, interlayer physical properties and flow blocking capacity.

3. The method for determining the distribution characteristics of interlayers within an oilfield block according to claim 1, characterized in that: Before inputting the interlayer data into the three-level stratification boundary data, each oil layer in each sedimentary unit in the three-level stratification boundary data is further divided into a plurality of layers, the method comprising: If the effective thickness of the oil layer is less than a predetermined value, the oil layer is divided into two sections. If the effective thickness of the oil layer is greater than or equal to the predetermined value, the oil layer is divided into three sections.

4. The method for determining the distribution characteristics of interlayers within an oilfield block according to claim 1, characterized in that: The interlayer plane distribution characteristics include at least: interlayer development width, extension distance, interlayer development ratio in different parts of the oil layer, and interlayer number ratio.

5. The method for determining the distribution characteristics of interlayers within an oilfield block according to claim 4, characterized in that: The interlayer development ratio is calculated by formula (1); The ratio of the number of interlayers is calculated using formula (2); Where C 沉积单元i夹层发育比例 is the development ratio of interlayer in sedimentary unit i, %; n 沉积单元i河道钻遇夹层井数 is the number of wells with intercalations in sedimentary unit i that encountered a river channel, n 沉积单元i钻遇河道总井数 is the total number of wells that encountered river channels in sedimentary unit i, mouth; D 沉积单元i夹层个数比例 is the ratio of intercalation number in single well of sedimentary unit i, number / well; m 沉积单元i河道内夹层数 is the total number of interlayers encountered in the channel of sedimentary unit i, 6. The method for determining the distribution characteristics of interlayers within an oilfield block according to claim 1, characterized in that: Before determining the remaining oil saturation near interlayers at different development positions in the work area based on the physical properties of the sealed coring well, the method further includes: According to the interlayer plane distribution diagram of the sedimentary unit, the lateral accumulation interlayer is identified, and the interlayer dip angle corresponding to the lateral accumulation interlayer is determined.

7. The method for determining the distribution characteristics of interlayers within an oilfield block according to claim 6, characterized in that: The method for identifying lateral accumulation interlayers comprises: An abandoned river channel is identified on the planar distribution diagram of the interlayer of the sedimentary unit, and the interlayer in the abandoned river channel is the lateral accumulation interlayer.

8. The method for determining the distribution characteristics of interlayers within an oilfield block according to claim 6, characterized in that: The method for determining the interlayer dip angle corresponding to the lateral accumulation interlayer comprises: Use formula (3) to calculate the intercalation angle corresponding to the lateral accumulation intercalation; α=H1 / H2 (3); Where H1 is the distance between the two wells containing the same lateral accumulation interlayer, and H2 is the difference in vertical depth of the same lateral accumulation interlayer between the two wells.

9. A device for determining the distribution characteristics of interlayers within an oilfield block, characterized in that: include: An acquisition unit is used to acquire basic static data within the target oilfield block, including at least: physical properties of sealed core wells, comprehensive water washing histogram, three-level stratification boundary data, sedimentary facies map and interlayer data; an interlayer development data determining unit, configured to determine the interlayer development data according to the physical properties of the sealed coring well and a comprehensive water-washing histogram; an interlayer characterization unit, configured to input the interlayer data into the three-level stratification boundary data, so that the interlayer data is displayed on a sedimentary facies belt map corresponding to each layer, and to draw the spatial distribution morphology of the interlayer along the river channel direction on the sedimentary facies belt map using a sedimentary microfacies characterization method to obtain a planar distribution map of the interlayer of the sedimentary unit; an interlayer distribution feature determination unit, configured to determine an interlayer plane distribution feature according to the interlayer plane distribution diagram of the deposition unit; A remaining oil saturation determination unit is used to determine the remaining oil saturation near interlayers at different development positions in the work area based on the physical properties of the sealed coring well; The interlayer distribution characteristic determination unit is used to determine the interlayer distribution characteristics according to the interlayer development data, the interlayer plane distribution characteristics and the remaining oil saturation.

Images