A method and apparatus for characterizing underwater distributary channel sand bodies
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2024-12-27
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies have significant errors in characterizing underwater distributary sand bodies, especially in terms of stratigraphic thickness and paleotopographic undulations at fault edges, making it difficult to accurately depict the distribution of underwater distributary channels.
By acquiring seismic data, fault data, and well logging data, we established a stratigraphic thickness distribution map and a planar distribution feature of the fault activity index. Combined with paleogeographic distribution maps, we meticulously depicted the sedimentary microfacies of underwater distributary channels.
This technology enables the detailed characterization of paleogeography and underwater distributary channel sedimentary microfacies based on fault differential activity, providing new technical methods and offering more precise sand body research tools for the oil and gas exploration and development field.
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Figure CN122307684A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of petroleum geological exploration and development technology, specifically relating to a method and apparatus for characterizing underwater distributary channel sand bodies. Background Technology
[0002] Subaqueous distributary channels are one of the most important microfacies types and high-quality hydrocarbon reservoirs in the delta front subfacies. They are the underwater extensions of terrestrial distributary channels, also known as subaqueous branching channels. During their marine extension, the channels widen, decrease in depth, increase in bifurcation, slow down in flow velocity, and increase in deposition velocity. Sediments are mainly sand and silt, with very little mud. Cross-bedding, wavy bedding, and scour-fill structures are commonly found, along with intra-layer deformation structures. Vertically, they appear lenticular in the flow profile, transitioning to fine-grained sediments laterally.
[0003] Currently, underwater distributary channel sand body characterization techniques mainly rely on core samples, well logging, and seismic prediction to characterize the distribution of underwater distributary channels. In terms of paleogeomorphic sedimentation, it is reflected by stratigraphic thickness or paleotopographic undulation. However, there are significant errors in stratigraphic thickness and paleotopographic undulation at fault edges, especially at the edges of stepped normal faults. Therefore, targeted paleogeomorphic restoration is needed for faults. Summary of the Invention
[0004] The purpose of this invention is to provide a method and apparatus for characterizing underwater distributary channel sand bodies, which takes into account fault-dependent activity-controlled sedimentation to characterize underwater distributary channel sand bodies, providing new technologies and methods for the study of underwater distributary channel sedimentary sand bodies in the field of oil and gas exploration and development.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: According to a first aspect of the present invention, a method for characterizing underwater distributary channel sand bodies is provided, comprising the following steps: S1: Obtain basic data information for the target work area, including seismic data, fault data, well logging data, and lithological data; S2: Based on the aforementioned basic data information, establish a stratigraphic thickness distribution map of the target work area; S3: Based on the aforementioned basic data information, establish the planar distribution characteristics of the fault activity index of the target work area; S4: Based on the stratigraphic thickness distribution map and combined with the planar distribution characteristics of the fault activity index, establish a paleogeographic distribution map of the target work area; S5: Based on the paleogeographic distribution map and the basic data information, depict the underwater distributary channel sedimentary microfacies map.
[0006] In one possible implementation, step S2 includes the following sub-steps: S21: Based on the aforementioned basic data information, establish a sequence stratigraphic framework for the target work area, and perform fine sequence stratigraphic division on the sequence stratigraphic framework to determine the target stratigraphic position; S22: Establish the formation thickness distribution map for the target stratum.
[0007] In one possible implementation, sub-step S21 includes: Based on the seismic data of the target work area, a three-dimensional stratigraphic model of the target work area is established; Based on the three-dimensional stratigraphic model, the isochronous sequence stratigraphic information of the target work area is extracted; Based on the isochronous sequence stratigraphic information, the sequence stratigraphic framework is established; Based on the well logging data of the target work area, the sequence stratigraphic framework is finely divided to determine the target stratigraphic position.
[0008] In one possible implementation, step S3 includes the following sub-steps: S31: Based on the fault data of the target work area, pick the normal faults in the target work area; S32: For each of the normal faults, along the fault strike, a set of fault activity indices is obtained at regular intervals to form the fault activity index distribution of the entire fault. S33: Based on the fault activity index distribution of all normal faults, the planar distribution characteristics of the fault activity index of the target work area are obtained.
[0009] In one possible implementation, the fault activity index is obtained in the following manner: Read the vertical thickness of the strata on the hanging wall and the footwall of the fault; The fault activity index is obtained by dividing the vertical thickness of the strata on the hanging wall of the fault by the vertical thickness of the strata on the footwall of the fault.
[0010] In one possible implementation, sub-step S33 includes: For each of the normal faults, the active and inactive segments of the entire fault are determined based on the distribution of the fault activity index. By combining the active and inactive segments of all normal faults on a plane, the planar distribution characteristics of the fault activity index of the target work area are obtained.
[0011] In one possible implementation, the segment of the fault with an activity index greater than 1 is the active segment of the fault, and the segment of the fault with an activity index less than or equal to 1 is the inactive segment of the fault.
[0012] In one possible implementation, step S4 includes the following sub-steps: S41: Based on the stratigraphic thickness distribution map and combined with the planar distribution characteristics of the fault activity index, determine the distribution of paleoslopes and paleogullies in the target work area. The paleogullies include main gullies and secondary gullies. The inactive section forms the main gully, the hanging wall of the fault at the active section forms the secondary gully, and the footwall of the fault at the active section forms the paleoslope. S42: Based on the distribution of ancient slopes and ancient gullies in the target work area, establish a paleogeographic distribution map of the target work area.
[0013] In one possible implementation, step S5 includes: developing an underwater diversion main channel at the main channel and developing underwater diversion branch channels at the secondary channel.
[0014] According to a second aspect of the present invention, an apparatus for characterizing underwater distributary channel sand bodies is provided, comprising: The information acquisition module is configured to acquire basic data information of the target work area, including seismic data, fault data, well logging data, and lithological data. A stratigraphic thickness establishment module is configured to establish a stratigraphic thickness distribution map of the target work area based on the basic data information obtained by the information acquisition module. A fault feature establishment module is configured to establish the planar distribution characteristics of the fault activity index of the target work area based on the basic data information obtained by the information acquisition module. The paleogeographic modeling module is configured to establish a paleogeographic distribution map of the target work area based on the stratigraphic thickness distribution map established by the stratigraphic thickness modeling module and combined with the fault activity index planar distribution features established by the fault feature modeling module. A sedimentary microfacies characterization module is configured to characterize an underwater distributary channel sedimentary microfacies map based on the paleogeomorphic distribution map established by the paleogeomorphic establishment module and the basic data information.
[0015] By adopting the above technical solution, the present invention has at least the following beneficial technical effects: The method and apparatus for characterizing underwater distributary channel sand bodies provided by this invention consider fault-dependent activity-controlled sedimentation to characterize underwater distributary channel sand bodies. Specifically, it first considers fault-dependent activity-controlled sedimentation to finely characterize paleogeography, and then, based on the finely characterized paleogeography, it characterizes underwater distributary channel sedimentary microfacies. This invention provides a new technology and method for the study of underwater distributary channel sedimentary sand bodies in the field of oil and gas exploration and development. Attached Figure Description
[0016] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.
[0017] Figure 1 A flowchart of the method for characterizing underwater distributary channel sand bodies provided by the present invention; Figure 2 This is a schematic diagram of co-depositional faults and non-co-depositional faults in one embodiment of the present invention; Figure 3 This is a planar fault distribution and fault-controlled sand map in one embodiment of the present invention; Figure 4 This is a diagram showing the distribution and activity of stepped faults on a cross-section in one embodiment of the present invention. Figure 5 This is a paleogeographic distribution map established in one embodiment of the present invention; Figure 6 This is a sedimentary microfacies diagram of an underwater distributary channel depicted in one embodiment of the present invention; Figure 7 A schematic block diagram of the apparatus for characterizing underwater distributary channel sand bodies provided by the present invention. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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. These embodiments are provided in this disclosure to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art.
[0019] It should be noted that in the description of this disclosure, words such as "including" or "contains" mean that the element preceding the word covers the element listed after the word, and does not exclude the possibility that it may also cover other elements.
[0020] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.
[0021] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.
[0022] The core of characterizing underwater distributary channel sedimentary microfacies lies in identifying the primary and secondary channels that control underwater distributary channels. The factors influencing these channels are twofold: regional tectonic differential subsidence and differential fault activity. Considering that regional tectonic subsidence involves large-scale, wide-ranging structural analysis and is unsuitable for small-scale, localized tectonic-controlled sedimentary studies, this invention addresses this issue by considering fault-dependent differential activity in sedimentary sedimentary studies. This provides a new technology and method for characterizing underwater distributary channel sand bodies, offering a novel approach for research in underwater distributary channel sedimentary sand bodies in the oil and gas exploration and development field.
[0023] According to a first aspect of the present invention, a method for characterizing underwater distributary channel sand bodies is provided, such as... Figure 1 As shown, the method includes the following steps: S1: Obtain basic data information of the target work area, including seismic data, fault data, well logging data, and lithological data; S2: Based on the basic data information, establish a stratigraphic thickness distribution map of the target work area; S3: Based on the basic data information, establish the planar distribution characteristics of the fault activity index of the target work area; S4: Based on the stratigraphic thickness distribution map and combined with the planar distribution characteristics of the fault activity index, establish a paleogeographic distribution map of the target work area; S5: Based on the paleogeographic distribution map, depict the underwater distributary channel sedimentary microfacies map.
[0024] The present invention will now be described in detail with reference to each step of the method.
[0025] In step S1, the work area where underwater distributary channel sand body characterization needs to be carried out is taken as the target work area, and various basic data information of the target work area are obtained, including seismic data, fault data, well logging data and lithological data.
[0026] In step S2, based on the basic data information obtained in step 1, a stratigraphic thickness distribution map of the target work area is established. The stratigraphic thickness distribution map is a map showing the thickness variation of a certain stratigraphic unit at different locations. In particular, the stratigraphic thickness distribution map of the target work area can be established based on seismic data, fault data, and well logging data of the target work area.
[0027] In one possible implementation, step S2 includes the following sub-steps: S21: Based on basic data, establish a sequence stratigraphic framework for the target work area, and perform fine sequence stratigraphic subdivision on the sequence stratigraphic framework to determine the target strata; S22: For the target strata, establish a stratigraphic thickness distribution map. Here, the target strata refer to the sedimentary strata of a single-stage underwater distributary channel. Sub-step S21 includes: establishing a three-dimensional stratigraphic model of the target work area based on seismic data; acquiring isochronous sequence stratigraphic information of the target work area based on the three-dimensional stratigraphic model; establishing a sequence stratigraphic framework based on the isochronous sequence stratigraphic information; and combining well logging data of the target work area to perform fine sequence stratigraphic subdivision on the sequence stratigraphic framework to determine the target strata. Determining the target strata includes determining the structural upper and lower boundaries of the target strata. Sub-step S22 includes: establishing a stratigraphic thickness distribution map for the target strata using methods such as the impression thickness method and the residual stratigraphic thickness method. For example, establishing a stratigraphic thickness distribution map using the impression thickness method includes: selecting the top boundary of the overlying strata corresponding to the target stratum, and obtaining the thickness between the top boundary of the overlying strata and the structural top boundary of the target stratum, thereby establishing a stratigraphic thickness distribution map; establishing a stratigraphic thickness distribution map using the residual stratigraphic thickness method includes: determining the underlying base level of the target stratum, and obtaining the thickness between the underlying base level and the structural top boundary of the target stratum, thereby establishing a stratigraphic thickness distribution map.
[0028] Specifically, seismic data for the target work area is acquired, and based on the seismic profiles in the data, existing strata and faults in the target work area are identified. A three-dimensional stratigraphic model of the target work area is then established using a global isochronous sequence stratigraphic construction method. All sequence boundaries of the target layer are extracted from the full three-dimensional data volume of the three-dimensional stratigraphic model, and isochronous sequence stratigraphic information (including interpretation of unconformities, faults, and major strata information) is extracted from the seismic data volume of the three-dimensional stratigraphic model. This information is then subjected to curve parameterization, and a parametric spatial domain (UVT) transformation is established, linking each (x, y, z) point in the three-dimensional stratigraphic model spatial domain to a (u, v, t) point in the aforementioned spatial domain (UVT). The full three-dimensional data volume is a seismic data volume containing sequence stratigraphic information. After extracting the sequence boundary information of the target area using the global isochronous sequence stratigraphic construction method, a three-dimensional stratigraphic model is established, allowing the extraction of the target sequence information. The seismic data volume contains basic information about seismic wave reflections, such as amplitude, frequency, and waveform. Subsequently, to improve the accuracy of sequence stratigraphy, wavelet analysis and time-frequency analysis were employed to perform fine-grained sequence stratigraphy in the target area. Based on seismic data and seismic interpretation data of the target area, time-frequency analysis was performed on the seismic profiles. Wavelet transform was then applied to the well logging data of the target area. After the wavelet transform, the results were used to calibrate and correct the sequence stratigraphy results from the time-frequency analysis, achieving fine-grained sequence stratigraphy. Seismic data (including both seismic data and seismic interpretation data) exhibits good continuity laterally and reflects sedimentary characteristics, but suffers from poor vertical resolution. Well logging data has strong vertical resolution, but its agreement with seismic profiles is poor. Based on the characteristics of both seismic and well logging data, a combination of wavelet transform and time-frequency analysis was used for sequence stratigraphy, which not only improves the agreement with seismic profiles but also achieves the goal of fine-grained sequence stratigraphy.
[0029] In one possible implementation, based on regional geological stratification standard wells, the geological stratification of individual wells is divided using the cyclic characteristics of well logging curves; by producing seismic synthetic records and stratigraphic calibration, the stratification of all individual wells in the area is corrected and unified; and based on the seismic phase axis reflection characteristics, the structural upper and lower boundaries of the sedimentary strata of a single-stage underwater distributary channel (i.e., the target stratum) are traced and interpreted.
[0030] In step S3, based on basic data (especially fault data), the planar distribution characteristics of the fault activity index in the target work area are established. Here, the planar distribution characteristics of the fault activity index refer to the distribution pattern of the fault activity index on the plane.
[0031] In one possible implementation, step S3 includes the following sub-steps: S31: Based on the fault data of the target work area, pick the normal faults in the target work area; S32: For each normal fault, along the fault strike, obtain a set of fault activity indices at certain intervals (e.g., 100m), thereby forming the fault activity index distribution of the entire fault; S33: Based on the fault activity index distribution of all normal faults, obtain the planar distribution characteristics of the fault activity index of the target work area.
[0032] A normal fault is a type of geological fault, classified according to the relative displacement of its two sides. A normal fault is one where, after its formation, the hanging wall subsides relatively while the footwall rises relatively. It is primarily formed by tensile forces and gravity. Figure 3 In the illustrated embodiment, two normal faults are shown.
[0033] In substep S32, the fault activity index is obtained as follows: the vertical thickness of the strata on the hanging wall and footwall of the fault is read; the vertical thickness of the strata on the hanging wall and footwall is divided to obtain the fault activity index. Specifically, the fault activity index is abbreviated as FGI, and FGI = vertical thickness of strata on the hanging wall / vertical thickness of strata on the footwall. For a single fault, along the fault strike, an FGI is picked at regular intervals (e.g., 50 meters) to finally obtain the distribution of the fault activity index for the entire fault.
[0034] In one possible implementation, sub-step S33 includes: determining the active and inactive segments of the entire fault for each normal fault's fault activity index distribution; and combining the active and inactive segments of all normal faults in a plane to obtain the planar distribution characteristics of the fault activity index of the target work area. Combining the active and inactive segments of all normal faults in a plane means connecting the inactive segments of all normal faults with lines in a plane to form a generally closed region. In other words, it separates the inactive and active segments of all normal faults with closed lines.
[0035] In one possible implementation, the segment of the fault with an activity index greater than 1 is the active segment of the fault, and the segment with an activity index less than or equal to 1 is the inactive segment of the fault.
[0036] Specifically, the Fault Activity Index (FGI) can be used to identify whether a fault is a syn-depositional fault. An FGI > 1 indicates a syn-depositional fault, while an FGI ≤ 1 indicates a non-syn-depositional fault. For example... Figure 2As shown in the example on the left, FGI > 1, so it is a syn-sedimentary fault. In the example on the right, FGI < 1, so it is a non-syn-sedimentary fault. By using the differences in activity of syn-sedimentary fault segments, we can identify the "active segments" that restrict sand body deposition and the "inactive segments" that transport sand bodies on a certain fault.
[0037] Cosedimentary faults, also known as growth faults, mainly develop at the edges of sedimentary basins. During the formation and development of sedimentary basins, the basin continuously subsides, sedimentation continues, and the outer side of the basin continuously uplifts; these processes are all caused by the continuous activity of faults controlling the basin's edge. Cosedimentary faults mainly develop at the edges of sedimentary basins, especially large and medium-sized rift basins, but secondary cosedimentary faults are also common within large basins. Cosedimentary faults vary in size, with large and medium-sized being the most prevalent. In terms of formation age, they mainly occur during the Mesozoic and Cenozoic eras, likely closely related to the widespread development of Mesozoic and Cenozoic rift basins. Cosedimentary faults have the following main characteristics: they are generally strike-normal faults, often appearing as a spoon-shaped structure with a steep upper surface and a gentle lower surface in cross-section; the strata on the hanging wall (i.e., the downthrown block) are significantly thickened, which is the most basic characteristic and identifying feature of cosedimentary faults. The fault activity index reflects the intensity of cosedimentary fault activity.
[0038] The method provided by this invention is particularly applicable to stepped normal fault-controlled sedimentary underwater distributary channel sand bodies. In this case, stepped normal faults are identified through seismic tectonic interpretation, and the fault activity index (FGI) is read for each fault according to the method described above (see...). Figure 4 This study establishes the planar distribution characteristics of the activity index of stepped normal faults, thereby constructing the paleogeography of sediment-carrying channels and the distribution of underwater distributary channels controlled by paleogeography. Among them, stepped normal faults refer to a combination of several normal faults with roughly the same dip arranged in parallel, with the upper side of each fault descending in a stepped manner in the same direction, also known as stepped faults.
[0039] In one possible implementation, the main source direction is explicitly defined as approximately perpendicular or obliquely intersecting the fault strike, with the fault dip pointing in the direction of the main source, i.e., opposite to the paleotopographic dip. This fault is called a reverse fault. The active section of the reverse fault forms a significant drop, restricting sand body progradation; the inactive section of the reverse fault is flat, becoming a sand transport gap (e.g., ...). Figure 3 (As shown).
[0040] In step S4, based on the stratigraphic thickness distribution map and combined with the planar distribution characteristics of the fault activity index, a paleogeographic distribution map of the target work area is established.
[0041] In one possible implementation, step S4 includes the following sub-steps: S41: Based on the stratigraphic thickness distribution map and combined with the planar distribution characteristics of the fault activity index, determine the distribution of paleoslopes and paleogullies in the target work area. The paleogullies include main gullies and secondary gullies. The inactive section forms the main gully, the hanging wall of the fault in the active section forms the secondary gully, and the footwall of the fault in the active section forms the paleoslope. S42: Based on the distribution of paleoslopes and paleogullies in the target work area, establish a paleogeographic distribution map of the target work area.
[0042] In one possible implementation, based on stratigraphic thickness distribution maps and combined with the planar distribution characteristics of fault activity indices, a paleogeographic model is established, including the distribution of paleohigh zones, paleoslopes, and paleogullies (e.g., Figure 5 (As shown). The inactive section forms a sand-carrying gap, creating the main channel. The hanging wall of the fault subsides, resulting in a low topographical position, restricting sand body progression perpendicular to the fault strike. This creates a secondary channel in the lower part, guiding sand body progression parallel to the fault strike. The footwall of the fault rises, creating a high topographical position, forming a paleoslope with a certain angle of inclination, restricting sand body progression. A thin sand body is deposited on the paleoslope. Depositional events generally do not occur in the higher parts of the paleoslope due to the higher topographical position. Paleohigh zones generally refer to areas with higher underwater paleo-uplift structures. Although underwater, the higher structure hinders the advancement of sand bodies in underwater distributary channels. In paleohigh zones, passerby deposition (almost no sediment) or sedimentary mudstone generally occurs. Paleohigh zones are determined by a combination of fault activity and thickness distribution; structurally higher areas are considered paleohigh zones.
[0043] In step S5, based on the paleogeographic distribution map and the basic data, a microfacies map of underwater distributary channels is drawn.
[0044] In one possible implementation, step S5 includes: developing an underwater diversion main channel at the main channel and developing underwater diversion branch channels at the secondary channel.
[0045] In one possible implementation, based on paleogeographic distribution maps, and using well logging curves from single wells, cuttings logging, seismic attributes, or inversion predictions, a sedimentary microfacies map of underwater distributary channels is depicted. The main channel develops the main underwater distributary channel, and the secondary channels develop underwater distributary tributaries (such as...). Figure 6 (As shown).
[0046] Based on the same concept, according to a second aspect of the present invention, an apparatus for characterizing sand bodies in underwater distributary channels is provided, such as... Figure 7As shown, the device includes: an information acquisition module 10, configured to acquire basic data information of the target work area, including seismic data, fault data, well logging data, and lithological data; a stratigraphic thickness establishment module 20, configured to establish a stratigraphic thickness distribution map of the target work area based on the basic data information acquired by the information acquisition module 10; a fault feature establishment module 30, configured to establish the planar distribution characteristics of the fault activity index of the target work area based on the basic data information acquired by the information acquisition module 10; a paleogeomorphology establishment module 40, configured to establish a paleogeomorphology distribution map of the target work area based on the stratigraphic thickness distribution map established by the stratigraphic thickness establishment module 20 and combined with the planar distribution characteristics of the fault activity index established by the fault feature establishment module 30; and a sedimentary microfacies characterization module 50, configured to characterize an underwater distributary channel sedimentary microfacies map based on the paleogeomorphology distribution map established by the paleogeomorphology establishment module 40 and the basic data information.
[0047] In summary, the method and apparatus for characterizing underwater distributary channel sand bodies provided by this invention considers fault-dependent activity controlling sedimentation to characterize underwater distributary channel sand bodies. Specifically, it first considers fault-dependent activity controlling sedimentation to finely characterize paleogeography, and then, based on the finely characterized paleogeography, it characterizes the underwater distributary channel sedimentary microfacies. This invention provides new technologies and methods for the study of underwater distributary channel sedimentary sand bodies in the field of oil and gas exploration and development. Specifically, based on the conventional method of normal fault-controlled sedimentation, this invention employs new methods and technologies to characterize underwater distributary channels: first, by using the differences in activity of segments of the same sedimentary fault, it identifies the "active segment" that restricts sand body deposition and the "inactive segment" that transports sand bodies on a certain fault; second, it combines the "active segments" and "inactive segments" of each fault to characterize the paleochannels (main channels and secondary channels) that transport sand bodies on the plane, and then characterizes the underwater distributary channel sedimentary microfacies based on the finely characterized paleogeography.
[0048] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. The sequence numbers of the disclosed embodiments of this invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.
[0049] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.
Claims
1. A method for characterizing underwater distributary channel sand bodies, characterized in that, Includes the following steps: S1: Obtain basic data information for the target work area, including seismic data, fault data, well logging data, and lithological data; S2: Based on the aforementioned basic data information, establish a stratigraphic thickness distribution map of the target work area; S3: Based on the aforementioned basic data information, establish the planar distribution characteristics of the fault activity index of the target work area; S4: Based on the stratigraphic thickness distribution map and combined with the planar distribution characteristics of the fault activity index, establish a paleogeographic distribution map of the target work area; S5: Based on the paleogeographic distribution map and the basic data information, depict the underwater distributary channel sedimentary microfacies map.
2. The method for characterizing underwater distributary channel sand bodies according to claim 1, characterized in that, Step S2 includes the following sub-steps: S21: Based on the aforementioned basic data information, establish a sequence stratigraphic framework for the target work area, and perform fine sequence stratigraphic division on the sequence stratigraphic framework to determine the target stratigraphic position; S22: Establish the formation thickness distribution map for the target stratum.
3. The method for characterizing underwater distributary channel sand bodies according to claim 2, characterized in that, Sub-step S21 includes: Based on the seismic data of the target work area, a three-dimensional stratigraphic model of the target work area is established; Based on the three-dimensional stratigraphic model, the isochronous sequence stratigraphic information of the target work area is extracted; Based on the isochronous sequence stratigraphic information, the sequence stratigraphic framework is established; Based on the well logging data of the target work area, the sequence stratigraphic framework is finely divided to determine the target stratigraphic position.
4. The method for characterizing underwater distributary channel sand bodies according to claim 1, characterized in that, Step S3 includes the following sub-steps: S31: Based on the fault data of the target work area, pick the normal faults in the target work area; S32: For each of the normal faults, along the fault strike, a set of fault activity indices is obtained at regular intervals to form the fault activity index distribution of the entire fault. S33: Based on the fault activity index distribution of all normal faults, the planar distribution characteristics of the fault activity index of the target work area are obtained.
5. The method for characterizing underwater distributary channel sand bodies according to claim 4, characterized in that, The fault activity index is obtained through the following method: Read the vertical thickness of the strata on the hanging wall and the footwall of the fault; The fault activity index is obtained by dividing the vertical thickness of the strata on the hanging wall of the fault by the vertical thickness of the strata on the footwall of the fault.
6. The method for characterizing underwater distributary channel sand bodies according to claim 4, characterized in that, Sub-step S33 includes: For each of the normal faults, the active and inactive segments of the entire fault are determined based on the distribution of the fault activity index. By combining the active and inactive segments of all normal faults on a plane, the planar distribution characteristics of the fault activity index of the target work area are obtained.
7. The method for characterizing underwater distributary channel sand bodies according to claim 6, characterized in that, The sections of the fault with an activity index greater than 1 are the active sections of the fault, and the sections with an activity index less than or equal to 1 are the inactive sections of the fault.
8. The method for characterizing underwater distributary channel sand bodies according to claim 6, characterized in that, Step S4 includes the following sub-steps: S41: Based on the stratigraphic thickness distribution map and combined with the planar distribution characteristics of the fault activity index, determine the distribution of paleoslopes and paleogullies in the target work area. The paleogullies include main gullies and secondary gullies. The inactive section forms the main gully, the hanging wall of the fault at the active section forms the secondary gully, and the footwall of the fault at the active section forms the paleoslope. S42: Based on the distribution of ancient slopes and ancient gullies in the target work area, establish a paleogeographic distribution map of the target work area.
9. The method for characterizing underwater distributary channel sand bodies according to claim 8, characterized in that, Step S5 includes: An underwater branch channel is developed at the main channel, and an underwater branch channel is developed at the secondary channel.
10. A device for characterizing sand bodies in underwater distributary channels, characterized in that, include: The information acquisition module is configured to acquire basic data information of the target work area, including seismic data, fault data, well logging data, and lithological data. A stratigraphic thickness establishment module is configured to establish a stratigraphic thickness distribution map of the target work area based on the basic data information obtained by the information acquisition module. A fault feature establishment module is configured to establish the planar distribution characteristics of the fault activity index of the target work area based on the basic data information obtained by the information acquisition module. The paleogeographic modeling module is configured to establish a paleogeographic distribution map of the target work area based on the stratigraphic thickness distribution map established by the stratigraphic thickness modeling module and combined with the fault activity index planar distribution features established by the fault feature modeling module. A sedimentary microfacies characterization module is configured to characterize an underwater distributary channel sedimentary microfacies map based on the paleogeomorphic distribution map established by the paleogeomorphic establishment module and the basic data information.