A method and apparatus for characterizing ancient river structures

Abstract

The application provides a method and device for characterizing ancient dark river structure, and solves the problem that there is no characterization method reflecting the difference of internal structure elements of ancient dark river at present. An embodiment of the application provides a method and device for characterizing ancient dark river structure, which comprises the following steps: obtaining single-well characteristics and inter-well characteristics, characterizing the external contour of the ancient dark river based on the single-well characteristics and the inter-well characteristics; obtaining identification marks, characterizing the internal structure of the ancient dark river based on the identification marks; and characterizing the structure of the ancient dark river based on the external contour of the ancient dark river and the internal structure of the ancient dark river.

Description

Technical Field

[0001] This invention relates to the field of oil reservoir development technology, and specifically to a method and apparatus for characterizing the structure of ancient underground rivers. Background Technology

[0002] Ancient underground rivers are near-horizontal caves primarily formed by dissolution, exhibiting characteristics similar to surface rivers, including large scale and clearly defined connections. They are an important reservoir type within fracture-vuggy oil reservoirs and are crucial for oilfield development. Characterizing the structural elements of ancient underground river reservoirs is key to oilfield development geology research, but currently, there are no methods to accurately represent the differences in internal structural elements within ancient underground rivers. Summary of the Invention

[0003] In view of this, the present invention provides a method and apparatus for characterizing the structure of ancient underground rivers, which solves the problem that there is currently no characterization method that can reflect the differences in the internal structural elements of ancient underground rivers.

[0004] An embodiment of the present invention provides a method and apparatus for characterizing the structure of ancient underground rivers, comprising:

[0005] Acquire single-well features and inter-well features, and characterize the external contour of the ancient underground river based on the single-well features and the inter-well features;

[0006] Obtain identification markers and characterize the internal structure of the ancient underground river based on the identification markers;

[0007] The structure of the ancient underground river is characterized based on its external outline and internal structure.

[0008] In one embodiment, the single-well characteristics include: logging response characteristics and well logging response characteristics.

[0009] In one embodiment, acquiring inter-well characteristics includes: identifying the inter-well characteristics based on marker layer flattening and / or seismic response characteristics.

[0010] In one implementation, characterizing the internal structure of the ancient underground river based on the identification markers includes:

[0011] The markers characterize the internal structural elements of the ancient underground river.

[0012] The internal structure of the ancient underground river is characterized based on the internal structural elements described above.

[0013] In one embodiment, the identification markers include at least one of developmental morphology, causal analysis, location, geomorphic features, well logging response, and seismic response.

[0014] In one embodiment, the structural elements include: an inlet, a main channel, a branch channel, a hall-shaped opening, and an outlet.

[0015] In one embodiment, the inlet includes: an open river, a sinkhole, a fracture, and fissures derived therefrom.

[0016] A device for characterizing the structure of ancient underground rivers includes:

[0017] The acquisition module is used to identify single-well characteristics and inter-well characteristics; and to acquire identification markers.

[0018] The identification module is used to characterize the external contour of the ancient underground river based on the single-well features and the inter-well features; to characterize the internal structure of the ancient underground river based on the identification markers; and to characterize the reservoir structure of the ancient underground river based on the external contour and the internal structure of the ancient underground river.

[0019] An electronic device includes a memory and a processor, the memory being used to store one or more computer instructions, wherein the one or more computer instructions, when executed by the processor, implement the method for characterizing ancient underground river structures as described above.

[0020] A computer-readable storage medium storing a computer program, which, when executed by a processor, is used to implement the method for characterizing ancient underground river structures as described in any one of the preceding claims.

[0021] This invention provides a method and apparatus for characterizing the structure of ancient underground rivers. Using the method described in this invention, the internal structural elements of the ancient underground river reservoir are described in greater detail. The differences between different structural elements can better guide the deployment of potential well locations, and the correlation between structural elements can better guide the formulation of water and gas injection schemes. The ancient underground river reservoir structure obtained using the above-mentioned method reflects the internal structure of the ancient underground river reservoir under karst regularity, which can constrain the establishment of three-dimensional geological models, reduce model uncertainty, and obtain models that better match geological reality. It has great application prospects in the development of carbonate fracture-vuggy reservoirs, and is of significant practical importance for geological modeling, numerical simulation, and rational formulation of development schemes for this type of reservoir. Furthermore, it can more accurately reveal the three-dimensional spatial distribution of this type of reservoir, providing important guidance for the efficient development of this type of reservoir. Attached Figure Description

[0022] Figure 1 The diagram shows a flowchart of a method for characterizing the structure of ancient underground rivers according to an embodiment of the present invention.

[0023] Figure 2 a~ Figure 2 Figure d shows a schematic diagram of the logging response characteristics of an ancient underground river according to an embodiment of the present invention.

[0024] Figure 3The diagram shown is a schematic cross-sectional view of an ancient underground river connecting wells provided in an embodiment of the present invention.

[0025] Figure 4 The diagram shown is a cross-sectional view of wave impedance properties provided in an embodiment of the present invention.

[0026] Figure 5 The diagram shown is a schematic diagram of three water inlet methods for an ancient underground river provided in an embodiment of the present invention.

[0027] Figure 6 a~ Figure 6 c is a schematic diagram of the seismic profile features of an ancient underground river inlet provided by an embodiment of the present invention.

[0028] Figure 7 a~ Figure 7 c is a schematic diagram of the seismic response characteristics of the main channel and branch channels of an ancient underground river, as provided in an embodiment of the present invention.

[0029] Figure 8 The diagram shown is a schematic representation of the development pattern of an ancient underground river hall cave provided in an embodiment of the present invention.

[0030] Figure 9 a~ Figure 9 c is a schematic diagram illustrating the response characteristics of a typical well hall cave provided in an embodiment of the present invention.

[0031] Figure 10 a~ Figure 10 b is a schematic diagram of the seismic attribute profiles of wells TH12164, TH12112, TH12182 and TH10112 provided in an embodiment of the present invention.

[0032] Figure 11 The diagram illustrates the cross-sectional views of wells TH12164, TH12112, TH12182, and TH10112, as provided in an embodiment of the present invention.

[0033] Figure 12 The diagram shown is a schematic representation of the planar identification results of underground river structural elements in the S94-TH12138 well area, provided by an embodiment of the present invention.

[0034] Figure 13 The diagram shown is a structural schematic of an ancient underground river structure characterization device provided in an embodiment of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Ancient underground rivers are near-horizontal caves primarily formed by dissolution, exhibiting characteristics similar to surface rivers, including large scale and clearly defined connections. They are an important reservoir type within fracture-vuggy oil reservoirs and are crucial for oilfield development. Characterizing the structural elements of ancient underground river reservoirs is key to oilfield development geology research, but currently, there are no methods to accurately represent the differences in internal structural elements within ancient underground rivers.

[0037] Early research on ancient underground rivers mainly focused on genetic descriptions and overall morphological depictions. Genetically, underground river structures were divided into hall caves, main stream caves, tributary caves, and terminal caves, and their internal filling characteristics were described. Alternatively, by analyzing the controlling factors of ancient underground rivers, types of karst caves within the channels, such as single-branch pipe types, network pipe types, and vertical shaft types, were summarized. Furthermore, using techniques such as seismic forward modeling, 3D visualization carving, and seismic coherence attribute extraction, combined with actual drilling, a set of methods and techniques for depicting and identifying ancient river channels was established. Another approach involved using wells... Seismic calibration and spectral decomposition techniques have been used to systematically characterize and identify ancient underground rivers in the western part of the Tarim Oilfield. Other methods classify underground rivers into three types: inflow-type, outflow-type, and aquifer-cavity type, and identify their overall morphology based on amplitude attributes and seismic reflection structure analysis. Alternatively, a comprehensive analysis of seismic, drilling, logging, well logging, and production dynamics data has been used to finely characterize the morphology of ancient underground rivers, further classifying the main channels into three types based on the size and filling degree of the tunnels: large-tunnel-deep zone, corridor zone, and silted zone. Characterizing ancient underground river reservoirs is crucial for the development of fracture-cavity reservoirs. However, the methods described above are insufficient for the detailed characterization required for the mid-to-late stages of oilfield development. Therefore, this invention proposes a method that comprehensively characterizes the internal structural elements of underground rivers from six aspects: development morphology, genetic analysis, location, geomorphological features, well logging response, and seismic response. This method provides a more detailed characterization of the underground river structure, better reflects the differences in internal structure, and offers greater guidance for 3D geological modeling and potential well location deployment.

[0038] Example 1:

[0039] Figure 1 The diagram shows a flowchart of a method for analyzing the structure of ancient underground rivers according to an embodiment of the present invention.

[0040] Figure 2 a~ Figure 2Figure b shows a schematic diagram of the logging response characteristics of an ancient underground river according to an embodiment of the present invention.

[0041] Figure 3 The diagram shown is a schematic cross-sectional view of an ancient underground river connecting wells provided in an embodiment of the present invention.

[0042] Figure 4 The diagram shown is a cross-sectional view of wave impedance properties provided in an embodiment of the present invention.

[0043] Figure 5 The diagram shown is a schematic diagram of three water inlet methods for an ancient underground river provided in an embodiment of the present invention.

[0044] Figure 6 a~ Figure 6 b is a schematic diagram of the seismic profile features of an ancient underground river inlet provided by an embodiment of the present invention.

[0045] Figure 7 a~ Figure 7 c is a schematic diagram of the seismic response characteristics of the main channel and branch channels of an ancient underground river, as provided in an embodiment of the present invention.

[0046] Figure 8 The diagram shown is a schematic representation of the development pattern of an ancient underground river hall cave provided in an embodiment of the present invention.

[0047] Figure 9 a~ Figure 9 b is a schematic diagram illustrating the response characteristics of a typical well hall cave provided in an embodiment of the present invention.

[0048] refer to Figure 1 As shown, this embodiment provides a method for characterizing the structure of an ancient underground river, wherein the ancient underground river structure includes the outer contour of the ancient underground river and the internal structure of the ancient underground river. The method for characterizing the structure of the ancient underground river includes:

[0049] Step S01: Obtain single-well features and inter-well features, and characterize the external contour of the ancient underground river based on the single-well features and inter-well features. The external contour of the ancient underground river can be identified from both single-well and inter-well perspectives.

[0050] The single-well characteristics of the ancient underground river are obtained, including well logging response characteristics and well logging response characteristics.

[0051] The inventors of this application have discovered that the distinctive characteristics of ancient underground rivers in drilling and logging are: during the drilling process, drill string venting, severe drilling fluid loss, drill string loss, and extremely low drilling time. In most cases, venting occurs in conjunction with severe well leakage.

[0052] The inventors of this application have discovered that the logging response characteristics of ancient underground rivers are as follows: the caliper logging curves show varying degrees of diameter expansion, with natural gamma ray values ​​greater than 5 API; the lateral resistivity logging curves at different depths exhibit a certain positive difference; the sonic logging value is greater than 50 μS / ft, and the neutron porosity logging value is close to zero; imaging logging (FMI) displays all or part of a dark image. The logging curve morphology of wells encountering underground rivers can be divided into four categories: composite type (such as...) Figure 2 As shown in a), box type (such as...) Figure 2 As shown in b), bell-shaped (as shown in b) Figure 2 As shown in c), finger-like (as shown in c) Figure 2 (as shown in d).

[0053] Methods for obtaining inter-well characteristics include: identifying the inter-well characteristics based on marker layer flattening and / or seismic response characteristics.

[0054] The inventors of this application have discovered that the ancient underground river system developed below the T74 unconformity interface is influenced by the groundwater level and is a near-horizontal karst cave system. The T56 unconformity interface of the Carboniferous system is the top boundary of the widely distributed thick limestone layers within the basin, and its logging curves show a distinct "double-peak" characteristic, which can be used as a marker layer. When the T56 interface is flattened, the top surface of the Ordovician carbonate rocks can approximate the paleogeography, and the ancient underground river system after multiple phases of karst alteration should be nearly parallel to the T56 marker layer. Therefore, by flattening the T56 interface, based on logging interpretation, approximately parallel ancient underground river reservoirs (such as...) can be identified on the well-connected profile. Figure 3 (As shown).

[0055] The inventors of this application have discovered that ancient underground rivers are often filled with sand, mud, breccia, calcite, or fluids. Compared to their hard surrounding carbonate rocks, these materials have lower velocity, density, and wave impedance, making the main body of the underground river clearly identifiable. Therefore, they often exhibit low-value areas with relatively high background seismic wave impedance. This demonstrates that continuous wave impedance properties can characterize the distribution of underground rivers between wells (e.g.,...). Figure 4 (As shown).

[0056] The single-well features and inter-well features obtained by the above method in this application can characterize the external contour of the ancient underground river.

[0057] Step S02: Obtain identification markers, and characterize the internal structure of the ancient underground river based on the identification markers. Characterizing the internal structure of the ancient underground river based on the identification markers includes: characterizing the internal structural elements of the ancient underground river based on the markers; and characterizing the internal structure of the ancient underground river based on the internal structural elements.

[0058] Identification markers may include at least one of the following: developmental morphology, genetic analysis, location, geomorphological features, well logging response, and seismic response.

[0059] Structural elements may include: inlet, main channel, branch channels, hall cave, and outlet.

[0060] A comprehensive analysis of developmental morphology, genesis, location, geomorphological features, well logging response, and seismic response is used to finely describe five structural elements: inlet, main channel, tributary channels, hall cave, and outlet. See Table 1 for details.

[0061] Table 1:

[0062]

[0063] ①Water inlet

[0064] Inlets are the main channels through which karst water enters underground rivers, either centrally or in a decentralized manner. These include three types: open rivers, sinkholes, and faults and their derived fissures (such as...). Figure 5 (As shown).

[0065] The main identifying features of open rivers as water inlets are: a strip-like shape in plan view and a trough-like shape in cross-section; in plan view, they appear as low-lying ancient landforms where they connect with underground rivers; in cross-section, they appear as a strong discontinuity in the continuous phase of seismic data, with wave troughs merging with the phase of the top surface of T74 (e.g., Figure 6 (as shown in a); the development location is at the confluence with an underground river. The internal structural elements of an ancient underground river possessing the aforementioned identifying features can be defined as an open river.

[0066] The main identifying features of sinkholes include: an elliptical shape in plan view and a conical or columnar shape in cross-section; a composite logging curve; and a location in a low-lying area of ​​ancient landforms in plan view, and a beaded distribution along an underground river in cross-section (e.g., ...). Figure 6 (As shown in b); the development location is at the beginning of the underground river and at the bend of the underground river. The internal structural elements of the ancient underground river with the above-mentioned identification marks can be defined as sinkholes.

[0067] The main identifying features of faults and their derived cracks are: planar morphology of strips or lines, and cross-sectional morphology of bands or veins; planar manifestation as low-lying areas, and cross-sectional manifestation as continuous strong phase discontinuities (e.g., Figure 6 (as shown in c); the development location is within a fault development zone. The internal structural elements of ancient underground rivers exhibiting the above-mentioned identifying characteristics can be defined as faults and their derived fissures.

[0068] ② Main river channel

[0069] The main channel is the section of the river where the water finally converges, and it develops in relatively low-lying parts of underground rivers (such as...). Figure 7 As shown in a), it extends long, is large in scale, and has a large water flow.

[0070] The main identifying features of a main channel include: a strip-like planar shape, a circular or elliptical profile, and a thickness greater than 5-10 meters; box-shaped or bell-shaped well logging curves; beaded reflections in the original seismic data; and a distinct, continuous low-value distribution of wave impedance properties, often found in relatively low-lying areas of the underground river. The internal structural elements of an ancient underground river exhibiting these identifying features can be defined as its main channel.

[0071] ③ Branch channels

[0072] The tributary channels generally converge towards the main channel, developing in relatively high sections of underground rivers and flowing towards lower sections before converging into the main channel (e.g., Figure 7 b— Figure 7 (as shown in c).

[0073] The main identifying features of tributary channels are: a planar branching strip shape; a cross-sectional shape that is circular or elliptical, with a thickness generally less than 5m; a finger-like appearance in well logging curves; beaded reflections in original seismic data; and a continuous low-value distribution of wave impedance properties, often found in relatively high parts of underground rivers. The internal structural elements of ancient underground rivers exhibiting these identifying features can be defined as tributary channels.

[0074] ④Hall Cave

[0075] Hall caves refer to large-scale caves (such as halls) formed by dissolution and collapse within a karst conduit network, resembling halls. Figure 8 (As shown).

[0076] The main identifying features of a hall-shaped cavern are: circular or elliptical plan and profile shapes, with a thickness greater than 10m; composite logging curves; and significant low impedance and large scale in seismic properties. These caverns often develop at the confluence of underground rivers, river bends, or where underground rivers intersect with faults. Well TK403 developed a typical hall-shaped cavern at depths of 5488-5554m, with a height of 66 meters. The cavern is heavily cemented, and the core samples are very complete. The cavern contains interlayered breccia, chemically infilled sandstone, and mudstone (e.g.,...). Figure 9 As shown in a), the wave impedance shows a significantly low value, with a large height and a large planar range compared to the main channel and tributary channel profiles (e.g., as shown in a). Figure 9 b- Figure 9 (As shown in c). The internal structural elements of ancient underground rivers with the above-mentioned identifying features can be defined as hall caves.

[0077] ⑤ Water outlet

[0078] The outlet of an underground river refers to the location where underground river water exits from the ground and enters the surface. It is mainly controlled by topography and geological structure and is distributed in low-lying areas.

[0079] The main identifying features of an outlet are: at the outlet, it mainly flows from an underground river to an open river or a karst spring, discharging onto the surface; the discharge area is located on either side of the valley floor or at the edge of a depression. The internal structural elements of an ancient underground river exhibiting these identifying features can be defined as an outlet.

[0080] Step S03: Characterize the ancient underground river structure based on its external outline and internal structure. The internal structural elements of the ancient underground river reservoir, described based on the external outline and internal structure, are more refined. The differences between different structural elements can better guide the deployment of potential well locations, and the correlation between structural elements can better guide the formulation of water and gas injection schemes.

[0081] The paleoriver reservoir structure obtained using the method described in this invention reflects the internal structure of the paleoriver reservoir under karst conditions. This structure can constrain the establishment of three-dimensional geological models, reduce model uncertainty, and yield models that better match geological realities. It has significant application prospects in the development of carbonate fracture-vuggy reservoirs, and is of great practical importance for geological modeling, numerical simulation, and the rational formulation of development plans for this type of reservoir. Furthermore, it can more accurately reveal the three-dimensional spatial distribution of this type of reservoir, providing important guidance for the efficient development of such reservoirs.

[0082] Example 2:

[0083] Figure 10 a~ Figure 10 b is a schematic diagram of the seismic attribute profiles of wells TH12164, TH12112, TH12182 and TH10112 provided in an embodiment of the present invention.

[0084] Figure 11 The diagram illustrates the cross-sectional views of wells TH12164, TH12112, TH12182, and TH10112, as provided in an embodiment of the present invention.

[0085] Figure 12 The diagram shown is a schematic representation of the planar identification results of underground river structural elements in the S94-TH12138 well area, provided by an embodiment of the present invention.

[0086] This embodiment uses a real-world example to characterize the river's horizontal distribution from two aspects: typical cross-sections.

[0087] (1) Typical cross-sectional analysis

[0088] refer to Figures 10-12This includes four single wells: TH12164, TH12112, TH12182, and TH10112. Taking the profile of TH12164-TH12112-TH12182-TH10112 as an example, this profile is nearly east-west oriented, following the direction of the underground river. Along this profile, there is a strip-like pattern with good continuity in wave impedance properties; all four wells show low impedance at their drilling locations (e.g.,...). Figure 10 As shown), based on the identification markers of the underground river structure, the drilling location of well TH12164 is located at the beginning of the underground river's development. The original seismic body shows a strong phase interruption, with the trough merging with the phase of the top surface of T74. The logging curve is a composite type, indicating that the drilling encountered the entrance of the underground river. Well TH12112 encountered the location outside the bend of the underground river, with a logging thickness of 67m, and is a hall-like cave. Wells TH12182 and TH10112 encountered branch channels (such as...). Figure 11 (As shown).

[0089] (2) Flat layout

[0090] Taking the S94-TH12138 well area of ​​the Tarim Oilfield as an example, through multi-profile prediction and planar analysis, 5 main river channels, 46 multi-level branch channels, 15 hall caves, and 28 sinkholes were identified (e.g., Figure 12 (As shown).

[0091] Example 3:

[0092] Figure 13 The diagram shown is a structural schematic of an ancient underground river structure characterization device provided in an embodiment of the present invention.

[0093] This embodiment provides a device 100 for characterizing ancient underground river structures, including an acquisition module 10 and an identification module 20. Wherein:

[0094] The function of module 10 is to identify single-well characteristics and inter-well characteristics; and to acquire identification markers.

[0095] The function of the identification module 20 is to characterize the external contour of the ancient underground river based on the single-well features and the inter-well features; to characterize the internal structure of the ancient underground river based on the identification markers; and to characterize the reservoir structure of the ancient underground river based on the external contour and the internal structure of the ancient underground river.

[0096] After the acquisition module 10 acquires the single-well features and inter-well features, the identification module 20 characterizes the external contour of the ancient underground river based on the single-well features and the inter-well features; after the acquisition module 10 acquires the identification mark, the identification module 20 characterizes the internal structure of the ancient underground river based on the identification mark; the identification module 20 then characterizes the reservoir structure of the ancient underground river based on the external contour and internal structure of the ancient underground river.

[0097] The acquisition module 10 acquires the single-well characteristics of the ancient underground river, including: logging response characteristics and well logging response characteristics.

[0098] The inventors of this application have discovered that the distinctive characteristics of ancient underground rivers in drilling and logging are: during the drilling process, drill string venting, severe drilling fluid loss, drill string loss, and extremely low drilling time. In most cases, venting occurs in conjunction with severe well leakage.

[0099] The inventors of this application have discovered that the logging response characteristics of ancient underground rivers are as follows: the caliper logging curves show varying degrees of diameter expansion, with natural gamma ray values ​​greater than 5 API; the lateral resistivity logging curves at different depths exhibit a certain positive difference; the sonic logging value is greater than 50 μS / ft, and the neutron porosity logging value is close to zero; imaging logging (FMI) displays all or part of a dark image. The logging curve morphology of wells encountering underground rivers can be divided into four categories: composite type (such as...) Figure 2 As shown in a), box type (such as...) Figure 2 As shown in b), bell-shaped (as shown in b) Figure 2 As shown in c), finger-like (as shown in c) Figure 2 (as shown in d).

[0100] The acquisition module 10 acquires inter-well features, including: identifying the inter-well features based on marker layer flattening and / or seismic response features.

[0101] The inventors of this application have discovered that the ancient underground river system developed below the T74 unconformity interface is influenced by the groundwater level and is a near-horizontal karst cave system. The T56 unconformity interface of the Carboniferous system is the top boundary of the widely distributed thick limestone layers within the basin, and its logging curves show a distinct "double-peak" characteristic, which can be used as a marker layer. When the T56 interface is flattened, the top surface of the Ordovician carbonate rocks can approximate the paleogeography, and the ancient underground river system after multiple phases of karst alteration should be nearly parallel to the T56 marker layer. Therefore, by flattening the T56 interface, based on logging interpretation, approximately parallel ancient underground river reservoirs (such as...) can be identified on the well-connected profile. Figure 3 (As shown)

[0102] The inventors of this application have discovered that ancient underground rivers are often filled with sand, mud, breccia, calcite, or fluids. Compared to their hard surrounding carbonate rocks, these materials have lower velocity, density, and wave impedance, making the main body of the underground river clearly identifiable. Therefore, they often exhibit low-value areas with relatively high background seismic wave impedance. This demonstrates that continuous wave impedance properties can characterize the distribution of underground rivers between wells (e.g.,...). Figure 4 (As shown).

[0103] The identification module 20 can identify the outer contour of the ancient underground river based on the single-well features and inter-well features obtained by the acquisition module 10.

[0104] The acquisition module 10 acquires identification markers and characterizes the internal structure of the ancient underground river based on the identification markers. Characterizing the internal structure of the ancient underground river based on the identification markers includes: characterizing the internal structural elements of the ancient underground river based on the markers; and characterizing the internal structure of the ancient underground river based on the internal structural elements.

[0105] Identification markers may include at least one of the following: developmental morphology, genetic analysis, location, geomorphological features, well logging response, and seismic response.

[0106] Structural elements may include: inlet, main channel, branch channels, hall cave, and outlet.

[0107] A comprehensive analysis of developmental morphology, genesis, location, geomorphological features, well logging response, and seismic response is used to finely describe five structural elements: inlet, main channel, tributary channels, hall cave, and outlet. See Table 1 for details.

[0108] Table 1:

[0109]

[0110]

[0111] ①Water inlet

[0112] Inlets are the main channels through which karst water enters underground rivers, either centrally or in a decentralized manner. These include three types: open rivers, sinkholes, and faults and their derived fissures (such as...). Figure 5 (As shown).

[0113] The main identifying features of open rivers as water inlets are: a strip-like shape in plan view and a trough-like shape in cross-section; in plan view, they appear as low-lying ancient landforms where they connect with underground rivers; in cross-section, they appear as a strong discontinuity in the continuous phase of seismic data, with wave troughs merging with the phase of the top surface of T74 (e.g., Figure 6 (as shown in a); the development location is at the confluence with an underground river. The internal structural elements of an ancient underground river possessing the aforementioned identifying features can be defined as an open river.

[0114] The main identifying features of sinkholes include: an elliptical shape in plan view and a conical or columnar shape in cross-section; a composite logging curve; and a location in a low-lying area of ​​ancient landforms in plan view, and a beaded distribution along an underground river in cross-section (e.g., ...). Figure 6 (As shown in b); the development location is at the beginning of the underground river and at the bend of the underground river. The internal structural elements of the ancient underground river with the above-mentioned identification marks can be defined as sinkholes.

[0115] The main identifying features of faults and their derived cracks are: strip-like or linear morphology in plan view, and band-like or vein-like morphology in cross section; in plan view, they appear as depressions in the terrain, and in cross section, they appear as continuous strong phase dislocations. Figure 6c) The development location is within a fault development zone. The internal structural elements of ancient underground rivers exhibiting the above-mentioned identifying characteristics can be defined as faults and their derived fissures.

[0116] ② Main river channel

[0117] The main channel is the section of the river where the water finally converges, and it develops in relatively low-lying parts of underground rivers (such as...). Figure 7 As shown in a), it extends long, is large in scale, and has a large water flow.

[0118] The main identifying features of a main channel include: a strip-like planar shape, a circular or elliptical profile, and a thickness greater than 5-10 meters; box-shaped or bell-shaped well logging curves; beaded reflections in the original seismic data; and a distinct, continuous low-value distribution of wave impedance properties, often found in relatively low-lying areas of the underground river. The internal structural elements of an ancient underground river exhibiting these identifying features can be defined as its main channel.

[0119] ③ Branch channels

[0120] The tributary channels generally converge towards the main channel, developing in relatively high sections of underground rivers and flowing towards lower sections before converging into the main channel (e.g., Figure 7 b— Figure 7 (as shown in c).

[0121] The main identifying features of tributary channels are: a planar branching strip shape; a cross-sectional shape that is circular or elliptical, with a thickness generally less than 5m; a finger-like appearance in well logging curves; beaded reflections in original seismic data; and a continuous low-value distribution of wave impedance properties, often found in relatively high parts of underground rivers. The internal structural elements of ancient underground rivers exhibiting these identifying features can be defined as tributary channels.

[0122] ④Hall Cave

[0123] Hall caves refer to large-scale caves (such as halls) formed by dissolution and collapse within a karst conduit network, resembling halls. Figure 8 (As shown).

[0124] The main identifying features of a hall-shaped cavern are: circular or elliptical plan and profile shapes, with a thickness greater than 10m; composite logging curves; and significant low impedance and large scale in seismic properties. These caverns often develop at the confluence of underground rivers, river bends, or where underground rivers intersect with faults. Well TK403 developed a typical hall-shaped cavern at depths of 5488-5554m, with a height of 66 meters. The cavern is heavily cemented, and the core samples are very complete. The cavern contains interlayered breccia, chemically infilled sandstone, and mudstone (e.g.,...). Figure 9 As shown in a), the wave impedance shows a significantly low value, with a large height and a large planar range compared to the main channel and tributary channel profiles (e.g., as shown in a). Figure 9 b- Figure 9(As shown in c). The internal structural elements of ancient underground rivers with the above-mentioned identifying features can be defined as hall caves.

[0125] ⑤ Water outlet

[0126] The outlet of an underground river refers to the location where underground river water exits from the ground and enters the surface. It is mainly controlled by topography and geological structure and is distributed in low-lying areas.

[0127] The main identifying features of an outlet are: at the outlet, it mainly flows from an underground river to an open river or a karst spring, discharging onto the surface; the discharge area is located on either side of the valley floor or at the edge of a depression. The internal structural elements of an ancient underground river exhibiting these identifying features can be defined as an outlet.

[0128] The identification module 20 characterizes the ancient underground river structure based on its external outline and internal structure. The internal structural elements of the ancient underground river reservoir, described using these characterizations, are more refined. The differences between these structural elements can better guide the deployment of potential well locations, and the correlations between structural elements can better guide the formulation of water and gas injection plans.

[0129] The paleo-underground river structure characterization device 100 in this embodiment represents the internal structure of the paleo-underground river reservoir under karst conditions. This can constrain the establishment of the three-dimensional geological model, reduce model uncertainty, and obtain a model that more closely matches geological reality. It has great application prospects in the development of carbonate fracture-vuggy reservoirs, and is of significant practical importance for geological modeling, numerical simulation, and the rational formulation of development plans for this type of reservoir. Furthermore, it can more accurately reveal the three-dimensional spatial distribution of this type of reservoir, providing important guidance for the efficient development of this type of reservoir.

[0130] Example 4:

[0131] This embodiment provides an electronic device, which may be a mobile phone, computer, or tablet computer, etc., including a memory and a processor. The memory stores a computer program, which, when executed by the processor, implements the method for characterizing ancient underground river structures as described in Embodiment 1. It is understood that the electronic device may further include an input / output (I / O) interface and communication components.

[0132] The processor is used to execute all or part of the steps in the method for characterizing the structure of ancient underground rivers, as described in Embodiment 1. The memory is used to store various types of data, which may include, for example, instructions for any application or method in the electronic device, as well as application-related data.

[0133] The processor may be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic components, and is used to execute the method for characterizing the ancient underground river structure in Embodiment 1 above.

[0134] The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0135] The electronic equipment used in this embodiment is employed to characterize the ancient underground river structure. The resulting description of the internal structural elements of the ancient underground river reservoir is more refined. The differences between various structural elements can better guide the deployment of potential well locations, and the correlation between structural elements can better guide the formulation of water and gas injection schemes. The ancient underground river reservoir structure obtained using the method described above reflects the internal structure of the ancient underground river reservoir under karst conditions. This can constrain the establishment of three-dimensional geological models, reduce model uncertainties, and obtain models that better match geological reality. It has great application prospects in the development of carbonate fracture-vuggy reservoirs, and is of significant practical importance for geological modeling, numerical simulation, and the rational formulation of development schemes for this type of reservoir. Furthermore, it can more accurately reveal the three-dimensional spatial distribution of this type of reservoir, providing important guidance for the efficient development of this type of reservoir.

[0136] Example 5:

[0137] This embodiment also provides a computer-readable storage medium. The functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0138] Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0139] The aforementioned storage media include: flash memory, hard disks, multimedia cards, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disks, optical discs, servers, APP application stores, and various other media capable of storing program verification codes, on which computer programs are stored. When the computer program is executed by a processor, it can implement the following method steps:

[0140] Step S01: Obtain single-well features and inter-well features, and characterize the external contour of the ancient underground river based on the single-well features and inter-well features. The external contour of the ancient underground river can be identified from both single-well and inter-well perspectives.

[0141] The single-well characteristics of the ancient underground river are obtained, including well logging response characteristics and well logging response characteristics.

[0142] The inventors of this application have discovered that the distinctive characteristics of ancient underground rivers in drilling and logging are: during the drilling process, drill string venting, severe drilling fluid loss, drill string loss, and extremely low drilling time. In most cases, venting occurs in conjunction with severe well leakage.

[0143] The inventors of this application have discovered that the logging response characteristics of ancient underground rivers are as follows: the caliper logging curves show varying degrees of diameter expansion, with natural gamma ray values ​​greater than 5 API; the lateral resistivity logging curves at different depths exhibit a certain positive difference; the sonic logging value is greater than 50 μS / ft, and the neutron porosity logging value is close to zero; imaging logging (FMI) displays all or part of a dark image. The logging curve morphology of wells encountering underground rivers can be divided into four categories: composite type (such as...) Figure 2 As shown in a), box type (such as...) Figure 2As shown in b), bell-shaped (as shown in b) Figure 2 As shown in c), finger-like (as shown in c) Figure 2 (as shown in d).

[0144] Methods for obtaining inter-well characteristics include: identifying the inter-well characteristics based on marker layer flattening and / or seismic response characteristics.

[0145] The inventors of this application have discovered that the ancient underground river system developed below the T74 unconformity interface is influenced by the groundwater level and is a near-horizontal karst cave system. The T56 unconformity interface of the Carboniferous system is the top boundary of the widely distributed thick limestone layers within the basin, and its logging curves show a distinct "double-peak" characteristic, which can be used as a marker layer. When the T56 interface is flattened, the top surface of the Ordovician carbonate rocks can approximate the paleogeography, and the ancient underground river system after multiple phases of karst alteration should be nearly parallel to the T56 marker layer. Therefore, by flattening the T56 interface, based on logging interpretation, approximately parallel ancient underground river reservoirs (such as...) can be identified on the well-connected profile. Figure 3 (As shown).

[0146] The inventors of this application have discovered that ancient underground rivers are often filled with sand, mud, breccia, calcite, or fluids. Compared to their hard surrounding carbonate rocks, these materials have lower velocity, density, and wave impedance, making the main body of the underground river clearly identifiable. Therefore, they often exhibit low-value areas with relatively high background seismic wave impedance. This demonstrates that continuous wave impedance properties can characterize the distribution of underground rivers between wells (e.g.,...). Figure 4 (As shown).

[0147] The single-well features and inter-well features obtained by the above method in this application can characterize the external contour of the ancient underground river.

[0148] Step S02: Obtain identification markers, and characterize the internal structure of the ancient underground river based on the identification markers. Characterizing the internal structure of the ancient underground river based on the identification markers includes: characterizing the internal structural elements of the ancient underground river based on the markers; and characterizing the internal structure of the ancient underground river based on the internal structural elements.

[0149] Identification markers may include at least one of the following: developmental morphology, genetic analysis, location, geomorphological features, well logging response, and seismic response.

[0150] Structural elements may include: inlet, main channel, branch channels, hall cave, and outlet.

[0151] A comprehensive analysis of developmental morphology, genesis, location, geomorphological features, well logging response, and seismic response is used to finely describe five structural elements: inlet, main channel, tributary channels, hall cave, and outlet. See Table 1 for details.

[0152] Table 1:

[0153]

[0154] ①Water inlet

[0155] Inlets are the main channels through which karst water enters underground rivers, either centrally or in a decentralized manner. These include three types: open rivers, sinkholes, and faults and their derived fissures (such as...). Figure 5 (As shown).

[0156] The main identifying features of open rivers as water inlets are: a strip-like shape in plan view and a trough-like shape in cross-section; in plan view, they appear as low-lying ancient landforms where they connect with underground rivers; in cross-section, they appear as a strong discontinuity in the continuous phase of seismic data, with wave troughs merging with the phase of the top surface of T74 (e.g., Figure 6 (as shown in a); the development location is at the confluence with an underground river. The internal structural elements of an ancient underground river possessing the aforementioned identifying features can be defined as an open river.

[0157] The main identifying features of sinkholes include: an elliptical shape in plan view and a conical or columnar shape in cross-section; a composite logging curve; and a location in a low-lying area of ​​ancient landforms in plan view, and a beaded distribution along an underground river in cross-section (e.g., ...). Figure 6 (As shown in b); the development location is at the beginning of the underground river and at the bend of the underground river. The internal structural elements of the ancient underground river with the above-mentioned identification marks can be defined as sinkholes.

[0158] The main identifying features of faults and their derived cracks are: planar morphology of strips or lines, and cross-sectional morphology of bands or veins; planar manifestation as low-lying areas, and cross-sectional manifestation as continuous strong phase discontinuities (e.g., Figure 6 (as shown in c); the development location is within a fault development zone. The internal structural elements of ancient underground rivers exhibiting the above-mentioned identifying characteristics can be defined as faults and their derived fissures.

[0159] ② Main river channel

[0160] The main channel is the section of the river where the water finally converges, and it develops in relatively low-lying parts of underground rivers (such as...). Figure 7 As shown in a), it extends long, is large in scale, and has a large water flow.

[0161] The main identifying features of a main channel include: a strip-like planar shape, a circular or elliptical profile, and a thickness greater than 5-10 meters; box-shaped or bell-shaped well logging curves; beaded reflections in the original seismic data; and a distinct, continuous low-value distribution of wave impedance properties, often found in relatively low-lying areas of the underground river. The internal structural elements of an ancient underground river exhibiting these identifying features can be defined as its main channel.

[0162] ③ Branch channels

[0163] The tributary channels generally converge towards the main channel, developing in relatively high sections of underground rivers and flowing towards lower sections before converging into the main channel (e.g., Figure 7 b— Figure 7 (as shown in c).

[0164] The main identifying features of tributary channels are: a planar branching strip shape; a cross-sectional shape that is circular or elliptical, with a thickness generally less than 5m; a finger-like appearance in well logging curves; beaded reflections in original seismic data; and a continuous low-value distribution of wave impedance properties, often found in relatively high parts of underground rivers. The internal structural elements of ancient underground rivers exhibiting these identifying features can be defined as tributary channels.

[0165] ④Hall Cave

[0166] Hall caves refer to large-scale caves (such as halls) formed by dissolution and collapse within a karst conduit network, resembling halls. Figure 8 (As shown).

[0167] The main identifying features of a hall-shaped cavern are: circular or elliptical plan and profile shapes, with a thickness greater than 10m; composite logging curves; and significant low impedance and large scale in seismic properties. These caverns often develop at the confluence of underground rivers, river bends, or where underground rivers intersect with faults. Well TK403 developed a typical hall-shaped cavern at depths of 5488-5554m, with a height of 66 meters. The cavern is heavily cemented, and the core samples are very complete. The cavern contains interlayered breccia, chemically infilled sandstone, and mudstone (e.g.,...). Figure 9 As shown in a), the wave impedance shows a significantly low value, with a large height and a large planar range compared to the main channel and tributary channel profiles (e.g., as shown in a). Figure 9 b- Figure 9 (As shown in c). The internal structural elements of ancient underground rivers with the above-mentioned identifying features can be defined as hall caves.

[0168] ⑤ Water outlet

[0169] The outlet of an underground river refers to the location where underground river water exits from the ground and enters the surface. It is mainly controlled by topography and geological structure and is distributed in low-lying areas.

[0170] The main identifying features of an outlet are: at the outlet, it mainly flows from an underground river to an open river or a karst spring, discharging onto the surface; the discharge area is located on either side of the valley floor or at the edge of a depression. The internal structural elements of an ancient underground river exhibiting these identifying features can be defined as an outlet.

[0171] Step S03: Characterize the ancient underground river structure based on its external outline and internal structure. The internal structural elements of the ancient underground river reservoir, described based on the external outline and internal structure, are more refined. The differences between different structural elements can better guide the deployment of potential well locations, and the correlation between structural elements can better guide the formulation of water and gas injection schemes.

[0172] The paleoriver reservoir structure obtained using the method described in this invention reflects the internal structure of the paleoriver reservoir under karst conditions. This structure can constrain the establishment of three-dimensional geological models, reduce model uncertainty, and yield models that better match geological realities. It has significant application prospects in the development of carbonate fracture-vuggy reservoirs, and is of great practical importance for geological modeling, numerical simulation, and the rational formulation of development plans for this type of reservoir. Furthermore, it can more accurately reveal the three-dimensional spatial distribution of this type of reservoir, providing important guidance for the efficient development of such reservoirs.

[0173] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention. It will be clearly understood by those skilled in the art that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0174] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0175] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0176] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner.

[0177] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0178] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0179] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, top, bottom, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of the components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0180] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0181] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0182] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of characterizing an ancient dark river structure, characterized by, The method comprises: obtaining single-well characteristics and inter-well characteristics, wherein the inter-well characteristics are obtained by taking a well curve with a bimodal display as a marker bed, and identifying the inter-well characteristics based on marker bed flattening; characterizing an external profile of the ancient dark river based on the single-well characteristics and the inter-well characteristics; obtaining identification markers, characterizing internal structural elements of the ancient dark river based on the identification markers, and characterizing an internal structure of the ancient dark river based on the internal structural elements, wherein the structural elements include an inlet, a main channel, a branch channel, a hall, and an outlet, the inlet includes a bright river, a sinkhole, a fracture, and a fissure derived from the fracture, and the identification markers include at least one of a development pattern, a genetic analysis, a location, a geomorphic feature, a well logging response, and a seismic response; characterizing the structure of the ancient dark river based on the external profile of the ancient dark river and the internal structure of the ancient dark river; wherein the identification markers of the bright river include a strip-shaped planar pattern and a groove-shaped cross-sectional pattern, a low-lying ancient landform on a planar surface, a junction with the dark river, a continuous strong phase interruption on a seismic data, a phase merging of a wave trough and a T74 top surface, and a development location at the junction with the dark river; the identification markers of the sinkhole include an elliptical planar pattern, a conical or columnar cross-sectional pattern, a composite well logging curve, a low-lying ancient landform on a planar surface, a beaded distribution along the dark river on a cross-sectional surface, and a development location at the beginning of the dark river or a bend of the dark river; the identification markers of the fracture and the fissure derived from the fracture include a strip-shaped or linear planar pattern, a strip-shaped or vein-shaped cross-sectional pattern, a low-lying landform on a planar surface, a continuous strong phase interruption on a cross-sectional surface, and a development location at a fracture development zone.

2. The method of characterizing an ancient river structure of claim 1, wherein, The single-well characteristics include logging response characteristics and well logging response characteristics.

3. The method of characterizing an ancient river structure of claim 1, wherein, The inter-well characteristics are obtained based on seismic response characteristics.

4. An ancient dark river structure characterizing apparatus based on the method of characterizing an ancient dark river structure according to any one of claims 1 to 3, characterized by, The method comprises: an obtaining module configured to obtain single-well characteristics and inter-well characteristics; an obtaining identification marker module, an identifying module configured to characterize an external profile of the ancient dark river based on the single-well characteristics and the inter-well characteristics, characterize an internal structure of the ancient dark river based on the identification markers, and characterize a structure of the ancient dark river based on the external profile of the ancient dark river and the internal structure of the ancient dark river.

5. An electronic device, comprising: A computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the method for characterizing the structure of the ancient dark river according to any one of claims 1-3.

6. A computer readable storage medium characterized by A computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the method for characterizing the structure of the ancient dark river according to any one of claims 1-3.

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