A composite point dam identification method and device

Abstract

The present disclosure relates to a composite point dam identification method and device, comprising: obtaining a abandoned river plane combination facies belt map according to the obtained random facies belt map of each deposition unit and the modern deposition aerial map; combining the abandoned river plane combination facies belt map with the sandstone thickness contour map to identify all point dam regions in the map, and drawing a stratigraphic correlation section along the direction of abandoned river side accumulation; if the level difference between the energy microfacies of the adjacent two production wells on the stratigraphic correlation section is two levels or more, the corresponding point dam region is a composite point dam. To solve the problem that when the point dam of the wide channel sand body is identified, it is always assumed to be a single point dam, and the composite point dam cannot be identified, so that the change of the heterogeneity difference of the sand body in the composite point dam cannot be understood, resulting in prominent imbalance of effectiveness, and the problem that the most suitable and effective fracturing, profile control and other schemes in oil displacement development cannot be prepared and subsequent adjustment measures cannot be guided, and the oil production maximization cannot be achieved.

Description

Technical Field

[0001] This disclosure relates to the field of oilfield reservoir research technology, and in particular to a method and apparatus for identifying composite point dams. Background Technology

[0002] Point bars are the main sedimentary features in the lateral aggradation process of meandering rivers. As sand-rich zones within the channel, they develop into relatively thick sand bodies, generally lenticular in shape. Previous studies assumed that point bars were all single points. However, during development, it was discovered that significant differences in lithology and physical properties exist within the same point bar, leading to prominent contradictions in the uneven treatment. Field profile investigations have confirmed that, whether in modern meandering river deposits or underground fluvial reservoir deposits, the probability of complete single-stage point bars is relatively low; they often appear as point bar complexes. Therefore, providing a method for identifying complex point bars in wide-channel sand bodies is crucial.

[0003] Existing patents related to composite point dam technology include patent number CN202010304464.7, which discloses a "method for describing the geometric features of a meandering river facies composite sand body configuration unit". Based on the planar geometric features of the configuration unit, both the single channel zone-level configuration unit and the composite point dam-level configuration unit are divided into multiple surface elements and digitized. Based on the data of the aforementioned surface elements, a computer program can describe and reconstruct the geometry and scale of single channel zone-level structural units and composite point dam-level structural units. Patent number CN201510574469.0 discloses a "quantitative characterization method for the scale of meandering river sand bodies," which identifies intact single-point dams within a meandering river sand body, determines the thickness of the single-point dam sand body, calculates the full-bank depth of the channel, and then calculates the scale of different levels of sand bodies and interlayers in the meandering river. This existing related technology has at least the following problems: 1. The existing technology describes the geometry and scale of composite point dam-level structural units, but does not describe the identification process and method of composite point dams; 2. It describes the scale of different levels of sand bodies and interlayers within a intact single-point dam in a meandering river sand body, but does not describe the configuration of composite point dams. Summary of the Invention

[0004] This disclosure proposes a method and apparatus for identifying composite point dams, which addresses the problem that existing point dam identification methods for wide-channel sand bodies default to identifying single point dams and fail to identify composite point dams. Consequently, the method fails to understand the changes in the heterogeneity of the sand body within the composite point dam, leading to significant imbalances in the effect and hindering the development of the most suitable and effective fracturing and profile control schemes and subsequent measures to maximize oil production.

[0005] According to one aspect of this disclosure, a method for identifying composite point dams is provided, comprising the steps of: acquiring random facies maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers, modern sedimentary aerial maps, and sandstone thickness contour maps;

[0006] Based on the random facies maps of each sedimentary unit and the modern sedimentary aerobatic maps, a planar assemblage facies map of abandoned channels is obtained;

[0007] By combining the planar combination facies map of the abandoned river channel with the sandstone thickness contour map, an overlay map of the abandoned river channel and sandstone thickness is obtained, and all point dam areas are identified in the overlay map of the abandoned river channel and sandstone thickness.

[0008] Using the identified point dam area, a stratigraphic correlation profile is drawn along the direction of the lateral accumulation of the abandoned river channel;

[0009] If the energy microphases of two adjacent production wells on the stratigraphic correlation profile differ in level by more than two levels, then the corresponding point dam area is a composite point dam.

[0010] Preferably, the method for obtaining random facies maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers includes:

[0011] Acquire stratified data of each sedimentary unit in the study area, and further subdivide all channel microfacies in the stratified data of each sedimentary unit into a predetermined number of channel energy microfacies.

[0012] The predetermined number of channel energy microfacies are labeled respectively, and random facies maps of each sedimentary unit with the predetermined number of channel energy microfacies labels are generated based on the labeled channel energy microfacies.

[0013] Preferably, the method for subdividing all channel microfacies in the stratified data of each sedimentary unit into a predetermined number of channel energy microfacies includes:

[0014] Determine the sand-to-land ratio of each sedimentary unit in the stratified data of each sedimentary unit;

[0015] Using the sand-to-soil ratio of each sedimentary unit, and based on the classification standard of channel sand energy microfacies in the core well, all channel microfacies in the stratified data of each sedimentary unit are subdivided into a predetermined number of channel energy microfacies.

[0016] Preferably, the method for obtaining a planar assemblage facies map of abandoned channels based on the random facies maps of each sedimentary unit and the modern sedimentary aerobatic chart includes:

[0017] Abandoned channels are identified by single wells on the random facies maps of each sedimentary unit. The random facies maps of each sedimentary unit with abandoned channels identified by single wells are combined with the modern sedimentary aerobatic maps according to the combination mode to obtain a combined facies map of abandoned channels.

[0018] Preferably, the method for identifying abandoned channels in a single well on a random facies map of each sedimentary unit includes:

[0019] The outer boundary of the composite sand body is identified on the generated random facies map of each sedimentary unit;

[0020] Based on the outer boundary of the composite sand body and the lithology and electrical characteristics of abandoned channels in the energy microfacies classification standard of channel sand in the core well, abandoned channels in the random facies zone diagram of each sedimentary unit are identified in a single well.

[0021] Preferably, the method for identifying all point dam areas in the superimposed map of abandoned river channels and sandstone thickness includes:

[0022] Select the abandoned river channel whose continuity in the superimposed diagram of the abandoned river channel and sandstone thickness meets the first predetermined condition;

[0023] In the abandoned river channel whose continuity meets the first predetermined condition, the area within its envelope that has sandstone thickness greater than or equal to the first predetermined value is selected as the point dam area.

[0024] Preferably, the method for obtaining the sandstone thickness contour map of the study area includes:

[0025] Stratification data of each sedimentary unit in the study area were obtained, and the sandstone thickness of each well in the stratification data of each sedimentary unit was statistically analyzed. Based on the sandstone thickness of each well, a sandstone thickness contour map was drawn.

[0026] Preferably, it further includes:

[0027] Obtain the phase zone diagram for plane identification of composite point dams;

[0028] Based on the positions of two adjacent production wells in the composite point dam region where the energy microphases of the sedimentary units differ by more than two levels, the boundary zone is drawn at the corresponding position on the composite point dam plane identification facies zone map.

[0029] According to one aspect of this disclosure, a composite point dam identification device is provided, comprising:

[0030] The acquisition unit is used to acquire random facies maps, modern sedimentary aerial maps, and sandstone thickness contour maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers.

[0031] The point dam identification unit is used to obtain a planar composite facies map of abandoned channels based on the random facies map of each sedimentary unit and the modern sedimentary aerial map; combine the planar composite facies map of abandoned channels with the sandstone thickness contour map to obtain an overlay map of abandoned channels and sandstone thickness, and identify all point dam areas in the overlay map of abandoned channels and sandstone thickness.

[0032] A stratigraphic correlation generation unit is used to draw a stratigraphic correlation profile along the direction of the lateral accumulation of the abandoned river channel using the identified point dam area.

[0033] The judgment unit is used to determine that if the energy microphases of two adjacent production wells on the stratigraphic correlation profile differ in level by more than two levels, then the corresponding point dam area is a composite point dam.

[0034] This disclosure has at least the following beneficial effects:

[0035] This disclosure proposes a method and apparatus for identifying composite point dams. By combining random facies maps of sedimentary units in the study area, each marked with a predetermined number of channel energy microfacies, with modern aerobatic sedimentary maps, a planar composite facies map of abandoned channels is obtained. Then, by combining this abandoned channel planar composite facies map with sandstone thickness contour maps, all point dam areas are accurately identified. Stratigraphic correlation profiles are drawn within the point dam areas. By determining whether the energy microfacies difference between adjacent production wells on the stratigraphic correlation profile reaches two or more levels, the point dam is identified as a composite point dam. This invention can accurately identify composite point dams in wide-channel sand bodies, understand the changes in sand body heterogeneity within composite point dams, and facilitate the development of fracturing, profile modification, and subsequent adjustments, thereby maximizing oil production. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0037] Figure 1 A flowchart of a composite point dam identification method according to an embodiment of the present disclosure is shown.

[0038] Figure 2 This diagram illustrates random facies zones of each sedimentary unit with a predetermined number of channel energy microfacies markers according to an embodiment of this disclosure.

[0039] Figure 3 A plan view of the phase zone of an abandoned river channel according to an embodiment of the present disclosure is shown.

[0040] Figure 4 An isometric map of sandstone thickness according to an embodiment of the present disclosure is shown.

[0041] Figure 5 An overlay diagram of abandoned river channels and sandstone thickness according to an embodiment of the present disclosure is shown.

[0042] Figure 6 A stratigraphic correlation plane well distribution diagram is shown according to an embodiment of the present disclosure.

[0043] Figure 7 A stratigraphic comparison profile of a composite point dam according to an embodiment of the present disclosure is shown.

[0044] Figure 8 A planar identification phase zone diagram of a composite point dam according to an embodiment of the present disclosure is shown. Detailed Implementation

[0045] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0046] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0047] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0048] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can 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 this disclosure.

[0049] Figure 1 A flowchart of a composite point dam identification method according to an embodiment of the present disclosure is shown. Figure 2 This diagram illustrates random facies zones of each sedimentary unit with a predetermined number of channel energy microfacies markers according to an embodiment of this disclosure. Figure 3 A plan view of the phase zone of an abandoned river channel according to an embodiment of the present disclosure is shown. Figure 4 An isometric map of sandstone thickness according to an embodiment of the present disclosure is shown. Figure 5 An overlay diagram of abandoned river channels and sandstone thickness according to an embodiment of the present disclosure is shown. Figure 6 A stratigraphic correlation plane well distribution diagram is shown according to an embodiment of the present disclosure. Figure 7 A stratigraphic comparison profile of a composite point dam according to an embodiment of the present disclosure is shown. Figure 8 A phase zone diagram for identifying composite point dams according to an embodiment of this disclosure is shown. Figure 1 , 2 As shown in Figures 3, 4, 5, 6, 7, and 8, a method for identifying composite point dams includes the following steps: Step S101: Obtain random facies maps, modern sedimentary aerial maps, and sandstone thickness contour maps of each sedimentary unit with a predetermined number of channel energy microfacies markers in the study area; Step S102: Obtain a planar composite facies map of abandoned channels based on the random facies maps of each sedimentary unit and the modern sedimentary aerial maps; Step S103: Combine the planar composite facies map of abandoned channels with the sandstone thickness contour map to obtain an overlay map of abandoned channels and sandstone thickness, and identify all point dam areas in the overlay map of abandoned channels and sandstone thickness; Step S104: Using the identified point dam areas, draw a stratigraphic correlation profile along the direction of the lateral accumulation of the abandoned channels; Step S105: Determine if the energy microfacies levels of two adjacent production wells on the stratigraphic correlation profile differ by more than two levels, then the corresponding point dam area is a composite point dam. This approach addresses the current practice of identifying point dams in wide-channel sand bodies, which often assumes they are single point dams and fails to identify composite point dams. Consequently, it fails to understand the variations in sand body heterogeneity within composite point dams, leading to significant imbalances in the effects of these dams. This hinders the development of the most suitable and effective fracturing and profile control schemes for oil recovery, as well as the guidance for subsequent adjustments to maximize oil production.

[0050] The composite point dam identification method provided in this embodiment of the invention specifically includes the following steps:

[0051] Step S101: Obtain random facies maps, modern sedimentary aerial maps, and sandstone thickness contour maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers.

[0052] In this disclosure, the method for obtaining random facies maps of each sedimentary unit in a study area with a predetermined number of channel energy microfacies markers includes: obtaining stratified data of each sedimentary unit in the study area; subdividing all channel microfacies in the stratified data of each sedimentary unit into a predetermined number of channel energy microfacies; marking the predetermined number of channel energy microfacies respectively; and generating random facies maps of each sedimentary unit with the predetermined number of channel energy microfacies markers based on the marked channel energy microfacies.

[0053] In this disclosure, the method for subdividing all channel microfacies in the stratified data of each sedimentary unit into a predetermined number of channel energy microfacies includes: determining the sand-soil ratio of each sedimentary unit in the stratified data of each sedimentary unit; and using the sand-soil ratio of each sedimentary unit, according to the classification standard of channel sand-energy microfacies in the core well, subdividing all channel microfacies in the stratified data of each sedimentary unit into a predetermined number of channel energy microfacies.

[0054] In this embodiment of the disclosure, when identifying composite point dams in the study area, the stratification data of each sedimentary unit in the study area are first obtained, and the stratification data of each sedimentary unit is stored in a stratification database. To further subdivide all channel microfacies in the stratification data of each sedimentary unit into a predetermined number of channel energy microfacies, the sand-to-land ratio of each sedimentary unit must first be determined. The method includes: calculating the ratio of sandstone thickness to stratigraphic thickness in the stratification data of each sedimentary unit to obtain the sand-to-land ratio.

[0055] Based on the classification criteria for channel sand energy microfacies from core wells, and considering the sand-to-soil ratio distribution range of each sedimentary unit in the channel sand and the electrical characteristics of the energy logging models, the channel microfacies are further subdivided into a predetermined number of channel energy microfacies. The predetermined number is 5.

[0056] The classification standard for energy microfacies of river sand from core wells specifically includes the following five levels:

[0057] (1) Class I channel sand energy microfacies:

[0058] Sandstone / stratum thickness (sand-soil ratio) [1.0-0.6], effective / stratum thickness [1.0-0.6], electrical logging curves are typical smooth thick box-shaped curves with high amplitude abrupt change at the bottom and gradual to abrupt change at the top, exhibiting extremely high amplitude and high amplitude difference;

[0059] (2) Class II channel sand energy microfacies:

[0060] Sandstone / stratum thickness [0.8-0.6], effective / stratum thickness [0.7-0.5], electrical logging curves are smooth bell-shaped or slightly toothed box-shaped, with high amplitude abrupt change at the bottom and gradual to abrupt change at the top, extremely high amplitude, and high amplitude difference;

[0061] (3) Class III channel sand energy microfacies:

[0062] Sandstone / stratum thickness [0.6-0.3], effective / stratum thickness [0.5-0.3], electrical logging curves are smooth bell-shaped, toothed thick box-shaped, smooth thin box-shaped, with high amplitude abrupt change at the bottom and gradual to abrupt change at the top, fine middle layer, high amplitude difference;

[0063] (4) Class IV channel sand energy microfacies:

[0064] Sandstone / stratum thickness [0.5-0.2], effective / stratum thickness [0.4-0.2], electrical logging curves are serrated bell-shaped, serrated thin box-shaped, smooth thin box-shaped, with high amplitude abrupt change at the bottom and gradual to abrupt change at the top, fine middle layer, high amplitude difference;

[0065] (5) Energy microphase of abandoned riverbed sand:

[0066] Sandstone / stratum thickness [0.5-0.2], effective / stratum thickness [0.4-0.2], electrical logging curves are smooth bell-shaped, toothed thin box-shaped, abrupt change at the bottom, gradual change at the top, fine middle layer, high amplitude difference.

[0067] The aforementioned five energy microfacies correspond to five levels. After subdividing the channel microfacies in the stratified data of the study area into five levels based on the above classification criteria, each of the five channel energy microfacies needs to be labeled. This labeling can be done using different colors to allow the subsequently generated random facies maps to more intuitively display the various parts of different types of channel energy microfacies. For example, the color of Class I channel sand energy microfacies is set to purplish-red; Class II channel sand energy microfacies to red; Class III channel sand energy microfacies to purple; Class IV channel sand energy microfacies to pink; and abandoned channel sand energy microfacies to blue. After color labeling, random facies maps of each sedimentary unit in the study area are generated using the five types of channel energy microfacies, each labeled with one of the five channel energy microfacies colors. In this embodiment, the generated random facies maps of each sedimentary unit with the five channel energy microfacies color labels are as follows: Figure 2 As shown.

[0068] Step S102: Based on the random facies map of each sedimentary unit and the modern sedimentary aerobatic map, obtain the planar composite facies map of the abandoned channel.

[0069] In this disclosure, the method for obtaining a planar composite facies map of abandoned channels based on the random facies maps of each sedimentary unit and the modern sedimentary aerobatic map includes: identifying abandoned channels in a single well on the random facies maps of each sedimentary unit; and combining the random facies maps of each sedimentary unit with the modern sedimentary aerobatic map in a planar manner according to a combination pattern to obtain a planar composite facies map of abandoned channels.

[0070] In this disclosure, the method for identifying abandoned channels in a single well on a random facies map of each sedimentary unit includes: identifying the outer boundary of the composite sand body on the generated random facies map of each sedimentary unit; and identifying the abandoned channels in the random facies map of each sedimentary unit in a single well based on the outer boundary of the composite sand body and the lithology and electrical logging characteristics of the abandoned channels in the energy microfacies classification standard of channel sand in the cored well.

[0071] In this embodiment of the disclosure, the method for identifying the outer boundary of the composite sand body includes: identifying two outer boundary lines between the channel facies and the non-channel facies on the random facies map of each sedimentary unit, which are the outer boundary lines of the composite sand body. The composite sand body is the superposition of multiple rivers, with a planar width reaching thousands of meters. On the random facies map of each sedimentary unit, five channel energy microfacies are identified by five colors. Other areas besides the five channel energy microfacies are non-channel facies. Identifying the two outer boundary lines of the composite sand body (superimposed rivers) between the channel facies (channel energy microfacies) and the non-channel facies constitutes the identification of the outer boundary of the composite sand body.

[0072] Among them, abandoned channels are laterally deposited abandoned channels. These are the last sediments left by the final lateral deposition of each channel within the composite sand body. Therefore, finding abandoned channels means finding the boundary regions between each individual channel within the composite sand body, and laterally deposited abandoned channels must be within the composite sand body. After identifying the outer boundary of the composite sand body, and combining the lithological and electrical logging characteristics of abandoned channels in the channel sand energy microfacies classification standard (i.e., the distribution range of sandstone thickness / stratum thickness (sandstone-to-soil ratio) in the sedimentary unit is [0.5, 0.2], the distribution range of effective thickness / stratum thickness is [0.4, 0.2], the curve smoothness includes smooth / serrated, and the curve shape includes thin box and bell shapes), laterally deposited abandoned channels can be identified in a single well within the composite sand body.

[0073] After identifying abandoned lateral sedimentary channels on a single well's random facies map of a sedimentary unit, the map needs to be combined with a modern aerobatic sedimentary map according to a set of patterns. The modern aerobatic sedimentary map is an aerial image of the modern sedimentary channel taken by an aircraft. The combination patterns for this modern aerobatic sedimentary map include three types: continuous high-curvature abandoned channels, single high-curvature abandoned channels, and arc-shaped strip abandoned channels. The river morphology captured in the modern aerobatic sedimentary map is combined with the abandoned channels identified by the single well on the random facies map of the sedimentary unit according to these three combination patterns. On the combined map, based on the river morphology, the abandoned lateral sedimentary channels identified by the single well are connected to draw their morphology and direction, ultimately resulting in the image shown below. Figure 3 The diagram shows the facies zone composition of the abandoned river channel. Figure 3 In the middle, the thick, dark strip-shaped area is the strip-shaped area of ​​abandoned lateral accumulation river channel.

[0074] In this disclosure, the method for obtaining sandstone thickness contour maps of the study area includes: obtaining stratification data of each sedimentary unit in the study area, statistically analyzing the sandstone thickness of a single well in the stratification data of each sedimentary unit, and drawing sandstone thickness contour maps based on the sandstone thickness of the single well.

[0075] In this embodiment of the disclosure, the stratification data of each sedimentary unit in the study area are geological data obtained after drilling production wells. The geological data includes the stratification data of each sedimentary unit, and the stratification data of each sedimentary unit includes the sandstone thickness of a single well. Based on the sandstone thickness of the single well, a sandstone thickness contour map is drawn. Figure 4 This is a sandstone thickness contour map drawn based on the sandstone thickness of a single well in each sedimentary unit, as described in this embodiment of the disclosure. Figure 4 In the sandstone thickness contour map, different colors correspond to different sandstone thicknesses, combined with... Figure 4 The coordinate table on the right side of the table can intuitively show the distribution range of sandstone thickness values ​​for each sedimentary unit.

[0076] Step S103: Combine the abandoned river channel planar composite facies map with the sandstone thickness contour map to obtain an overlay map of abandoned river channel and sandstone thickness, and identify all point dam areas in the overlay map of abandoned river channel and sandstone thickness.

[0077] In this disclosure, the method for identifying all point dam areas in an overlay map of abandoned river channels and sandstone thickness includes: selecting abandoned river channels whose continuity in the overlay map of abandoned river channels and sandstone thickness meets a first predetermined condition; and selecting areas within the envelope of abandoned river channels whose continuity meets the first predetermined condition as point dam areas, where the sandstone thickness is greater than or equal to a first predetermined value.

[0078] In this embodiment of the disclosure, the first predetermined condition is: within the strip-shaped area of ​​the abandoned river channel in the planar composite facies map, the actual drilling encounter rate of the abandoned river channel is greater than or equal to a predetermined percentage; wherein, the predetermined percentage can be set according to the number and distribution of oil wells in the study area, such as setting it to 60%, then the drilling encounter rate must be greater than or equal to 60%. The drilling encounter rate is: the percentage of abandoned river channel oil wells actually drilled within the strip-shaped area of ​​the abandoned river channel out of the expected number of abandoned river channel oil wells to be drilled. That is, according to... Figure 3 In the abandoned river channel strip area identified in the planar composite facies map, a higher number of drilled single wells (oil layer wells) within that area indicates... Figure 3 The more accurate the identified abandoned river channel areas, the better. The expected number of wells to encounter abandoned river channel oil formations can be set based on the actual number and distribution of oil wells on the well rows in the study area. For example, if the abandoned river channel strip area spans 100 well rows, and the width of the abandoned river channel is less than the distance between two wells, assuming that each well row it spans has one well within the abandoned river channel strip area, then the expected number of wells to encounter abandoned river channel oil formations is 100. If the actual number of single wells encountered within the abandoned river channel strip area reaches 60 or more, the encounter rate will be greater than or equal to 60%, indicating that the continuity of the abandoned river channel meets the first predetermined condition.

[0079] In a continuous strip-shaped area of ​​an abandoned river channel that meets the first predetermined condition, the thickness of the developed sandstone within its enclosed area must be greater than or equal to a first predetermined value, where the first predetermined value is 2.5 meters, to be considered a point dam area. When the sandstone thickness within the enclosed area of ​​a continuous strip-shaped area of ​​an abandoned river channel that meets the first predetermined condition is greater than or equal to 2.5 meters, the abandoned river channel area is identified as a point dam area. For example... Figure 5 In the overlay map of abandoned river channels and sandstone thickness shown, the area enclosed by the box is the identified point dam area.

[0080] Step S104: Using the identified point dam area, draw a stratigraphic correlation profile along the direction of the lateral accumulation of the abandoned river channel.

[0081] In this embodiment of the disclosure, after identifying all point dam areas on the overlay map of abandoned river channels and sandstone thickness, a stratigraphic correlation profile is drawn along the lateral accretion direction of the abandoned river channels. The method for drawing the stratigraphic correlation profile is to draw a line from the opening of the strip-shaped abandoned river channel within the point dam area towards the closing direction. The result is as follows: Figure 6 The stratigraphic correlation plane map showing the distribution of wells is shown. Figure 6 Three correlation profiles were drawn within the three point dam areas. Based on these three correlation profiles, a stratigraphic correlation profile map can be generated, which can display the production well curve morphology and sandstone thickness within the three point dam areas.

[0082] Step S105: If the energy microphases of two adjacent production wells on the stratigraphic correlation profile differ in level by more than two levels, then the corresponding point dam area is a composite point dam.

[0083] In this embodiment of the disclosure, a stratigraphic correlation plane connecting well distribution map is drawn after the stratigraphic correlation profile is plotted ( Figure 6 On the stratigraphic correlation profile, determine whether the energy microfacies levels of the sedimentary units corresponding to any two adjacent production wells on the stratigraphic correlation profile differ by more than two levels. That is, if the energy microfacies levels of the sedimentary units corresponding to any two adjacent production wells on the stratigraphic correlation profile within one of the point bar areas differ by more than two levels, then the energy microfacies levels of the sedimentary units corresponding to any two adjacent production wells on the stratigraphic correlation profile (reference...) Figure 2 If the energy microfacies of the sedimentary units corresponding to the two adjacent production wells are classified as Class I and Class III, it indicates that the energy microfacies between the two adjacent production wells differ by two levels, and the point bar area is considered a composite point bar. If the energy microfacies levels of the sedimentary units corresponding to all two adjacent production wells on the stratigraphic correlation profile are the same or differ by no more than two levels, then the point bar area is a single point bar.

[0084] If the energy microfacies levels of sedimentary units corresponding to two adjacent production well locations within a point dam area differ by more than two levels, it indicates that the sandstone thickness within the point dam exhibits a thick-thin-thick trend, consistent with the characteristics of a composite point dam. The stratigraphic correlation profile generated based on the identified composite point dams in this embodiment is shown below. Figure 7 As shown, in Figure 7 The data shows that the sandstone thickness changes in a thick-thin-thick pattern, and the production well curves are also different, indicating that the point dam area is a composite point dam.

[0085] This disclosure also includes: obtaining a composite point dam planar identification facies map; and drawing a boundary zone on the composite point dam planar identification facies map at the corresponding positions of two adjacent production wells in the composite point dam region whose energy microphases of the sedimentary units differ by more than two levels.

[0086] In this embodiment of the disclosure, the composite point dam is composed of two parts: early sedimentation and lateral sedimentation point dam. If the production well curve morphology characteristics in the early sedimentation area are similar, the production well curves and sandstone thickness of the lateral sedimentation point dam and the early sedimentation part are significantly different, and the sandstone thickness shows a change from thick to thin to thick, that is, an abrupt change occurs.

[0087] After identifying the composite point dam, it is necessary to draw the boundary zone on the composite point dam planar identification facies map at the location where the sandstone thickness abruptly changes in the composite point dam area, such as... Figure 8 The planar identification facies map of the composite point dam shows the boundary changes between early sedimentary deposits and later-formed lateral accretion point dams within the composite point dam area. The boundary zones drawn on this planar identification facies map reveal the differences in lithological properties within the composite point dam, which can be used to guide the analysis of the effective direction of injection-production well groups and to formulate potential tapping measures.

[0088] In this embodiment of the disclosure, the executing entity of the composite point dam identification method can be a composite point dam identification device. For example, the composite point dam identification method can be executed by a terminal device, a server, or other processing devices. The terminal device can be a user equipment (UE), mobile device, user terminal, terminal, cellular phone, cordless phone, personal digital assistant (PDA), handheld device, computing device, vehicle-mounted device, wearable device, etc. In some possible implementations, the composite point dam identification method can be implemented by a processor calling computer-readable instructions stored in memory.

[0089] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply 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.

[0090] This disclosure also provides a composite point dam identification device, comprising: an acquisition unit for acquiring random facies maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers, modern sedimentary aerobatic maps, and sandstone thickness contour maps;

[0091] The point dam identification unit is used to obtain a planar composite facies map of abandoned channels based on the random facies map of each sedimentary unit and the modern sedimentary aerial map; combine the planar composite facies map of abandoned channels with the sandstone thickness contour map to obtain an overlay map of abandoned channels and sandstone thickness, and identify all point dam areas in the overlay map of abandoned channels and sandstone thickness.

[0092] A stratigraphic correlation generation unit is used to draw a stratigraphic correlation profile along the direction of the lateral accumulation of the abandoned river channel using the identified point dam area.

[0093] The judgment unit is used to determine that if the energy microphases of two adjacent production wells on the stratigraphic correlation profile differ in level by more than two levels, then the corresponding point dam area is a composite point dam.

[0094] In some embodiments, the functions or units and modules included in the apparatus provided in this disclosure can be used to execute the methods described in the above method embodiments. The specific implementation can be referred to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0095] This disclosed method for identifying composite point dams can identify composite point dams in composite channel sand bodies, dissect the changes in heterogeneity differences within the sand bodies, identify the boundary zones between early sedimentary and later-formed lateral accretion point dams, and clarify the degree of sand body connectivity. It can accurately guide the analysis of the effective direction of polymer flooding wells, and for adjusting measures such as fracturing schemes, it implements well parameter adjustments according to the principle of "high flowing pressure in favorable directions and low flowing pressure in unfavorable directions," solving the problem of large differences in planar effective direction, which is of great significance for maintaining stable oilfield production. It improves the understanding of heterogeneity within point dams, is applicable to the analysis of the activation status of medium-to-high permeability reservoirs, and has broad prospects for application.

[0096] In practical application experiments, a target well group, before dissection, appeared to consist entirely of channel sand within a point bar, seemingly homogeneous, based on facies maps. However, the water content of the surrounding four oil wells varied, with two wells exhibiting high flowing pressure (over 5 Ma) and two wells exhibiting low flowing pressure (below 5 Ma), the cause of which was unclear. Using the composite point bar identification method disclosed in this paper, the area where the well group is located was identified as a composite point bar. Two wells are connected to water wells, belonging to Class I channel connectivity, indicating good connectivity, low pressure, and early deposition. The other two wells are connected to water wells, belonging to Class I and Class III channel connectivity, with reduced oil well thickness and deteriorating lithological properties, resulting in poor connectivity, high pressure, and location on the boundary between early deposition and lateral deposition point bars. By analyzing the sand body connectivity, the differences in planar effect were clarified. Following the principle of "high flowing pressure in favorable directions and low flowing pressure in unfavorable directions," the flow parameters of two low-flow-pressure wells were adjusted to low levels and intermittent pumping, while the flow parameters of two high-flow-pressure wells were adjusted to high levels. After the adjustment, the water cut of the well group decreased more uniformly, reflecting a more even effect and solving the problem of large differences in planar effect. Using the composite sand body identification method, the connectivity of the injection and production well groups was analyzed. During the water cut decline period, planar adjustments were implemented in 24 wells, resulting in a daily increase of 1.6 tons of oil per well and a decrease in water cut of 0.8 percentage points.

[0097] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are 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 chosen to best explain the principles, practical applications, or technical improvements to the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for identifying composite point dams, characterized in that, Including the following steps: Obtain random facies maps, modern sedimentary aerial maps, and sandstone thickness contour maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers; Based on the random facies maps of each sedimentary unit and the modern sedimentary aerobatic maps, a planar assemblage facies map of abandoned channels is obtained; By combining the planar combination facies map of the abandoned river channel with the sandstone thickness contour map, an overlay map of the abandoned river channel and sandstone thickness is obtained, and all point dam areas are identified in the overlay map of the abandoned river channel and sandstone thickness. Using the identified point dam area, a stratigraphic correlation profile is drawn along the direction of the lateral accumulation of the abandoned river channel; If the energy microphases of two adjacent production wells on the stratigraphic correlation profile differ in level by more than two levels, then the corresponding point dam area is a composite point dam.

2. The composite point dam identification method according to claim 1, characterized in that, The step of obtaining random facies maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers includes: Acquire stratified data of each sedimentary unit in the study area, and further subdivide all channel microfacies in the stratified data of each sedimentary unit into a predetermined number of channel energy microfacies. The predetermined number of channel energy microfacies are labeled respectively, and random facies maps of each sedimentary unit with the predetermined number of channel energy microfacies labels are generated based on the labeled channel energy microfacies.

3. The composite point dam identification method according to claim 2, characterized in that, The step of subdividing all channel microfacies in the stratified data of each sedimentary unit into a predetermined number of channel energy microfacies includes: Determine the sand-to-land ratio of each sedimentary unit in the stratified data of each sedimentary unit; Using the sand-to-soil ratio of each sedimentary unit, and based on the classification standard of channel sand energy microfacies in the core well, all channel microfacies in the stratified data of each sedimentary unit are subdivided into a predetermined number of channel energy microfacies.

4. The composite point dam identification method according to claim 1, characterized in that, The step of obtaining the planar assemblage facies map of abandoned channels based on the random facies maps of each sedimentary unit and the modern sedimentary aerobatic map includes: Abandoned channels are identified by single wells on the random facies maps of each sedimentary unit. The random facies maps of each sedimentary unit where the abandoned channels are identified by single wells are combined with the modern sedimentary aerobatic maps according to the combination mode to obtain a combined facies map of abandoned channels.

5. The composite point dam identification method according to claim 4, characterized in that, The step of identifying abandoned channels in a single well on a random facies map of each sedimentary unit includes: The outer boundary of the composite sand body is identified on the generated random facies map of each sedimentary unit; Based on the outer boundary of the composite sand body and the lithology and electrical characteristics of abandoned channels in the energy microfacies classification standard of channel sand in the core well, abandoned channels in the random facies zone diagram of each sedimentary unit are identified in a single well.

6. The composite point dam identification method according to claim 1, characterized in that, The step of identifying all point dam areas in the superimposed map of abandoned river channels and sandstone thickness includes: Select the abandoned river channel whose continuity in the superimposed diagram of the abandoned river channel and sandstone thickness meets the first predetermined condition; In the abandoned river channel whose continuity meets the first predetermined condition, the area within its envelope that has sandstone thickness greater than or equal to the first predetermined value is selected as the point dam area.

7. The composite point dam identification method according to claim 1, characterized in that, The steps to obtain sandstone thickness contour maps of the study area include: Stratification data of each sedimentary unit in the study area were obtained, and the sandstone thickness of each well in the stratification data of each sedimentary unit was statistically analyzed. Based on the sandstone thickness of each well, a sandstone thickness contour map was drawn.

8. The composite point dam identification method according to any one of claims 1-7, characterized in that, Also includes: Obtain the phase zone diagram for plane identification of composite point dams; Based on the positions of two adjacent production wells in the composite point dam region where the energy microphases of the sedimentary units differ by more than two levels, the boundary zone is drawn at the corresponding position on the composite point dam plane identification facies zone map.

9. A composite point dam identification device, characterized in that, include: The acquisition unit is used to acquire random facies maps, modern sedimentary aerial maps, and sandstone thickness contour maps of each sedimentary unit in the study area with a predetermined number of channel energy microfacies markers. The point dam identification unit is used to obtain a planar composite facies map of abandoned channels based on the random facies map of each sedimentary unit and the modern sedimentary aerial map; combine the planar composite facies map of abandoned channels with the sandstone thickness contour map to obtain an overlay map of abandoned channels and sandstone thickness, and identify all point dam areas in the overlay map of abandoned channels and sandstone thickness. A stratigraphic correlation generation unit is used to draw a stratigraphic correlation profile along the direction of the lateral accumulation of the abandoned river channel using the identified point dam area. The judgment unit is used to determine that if the energy microphases of two adjacent production wells on the stratigraphic correlation profile differ in level by more than two levels, then the corresponding point dam area is a composite point dam.

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