Methods, apparatus, devices, and storage media of determining a farshore underwater fan

Abstract

The method, device, equipment and storage medium for determining a distal submarine fan are provided in the embodiments of the present disclosure, and belong to the field of oil and gas exploitation. The method comprises the following steps: determining a source direction of the distal submarine fan; determining a development position of a fan root of the distal submarine fan on a section of a fault according to a paleofall of a first stratum of the fault and the source direction; determining a migration direction of a sand body according to a thickness of the first stratum of a downthrown side of the fault; determining a planar distribution characteristic of a sandstone thickness of the first stratum of the downthrown side of the fault; and determining a distribution characteristic of the distal submarine fan according to the development position of the fan root on the section of the fault, the migration direction of the sand body and the planar distribution characteristic. The embodiments of the present disclosure can effectively identify the fan root, fan middle and fan end subfacies of the distal submarine fan.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of oil and gas exploitation, and particularly relates to a method and device for determining a far-shore subaqueous fan, equipment and a storage medium. BACKGROUND

[0002] The far-shore subaqueous fan belongs to a type of gravity flow depositional system, and has the characteristics of large scale and sheet distribution. The far-shore subaqueous fan includes a fan root, a fan middle and a fan end, and is both a good reservoir and an important oil and gas carrier. Therefore, the identification of the distribution characteristics of the far-shore subaqueous fan and the exploration of the far-shore subaqueous fan are crucial.

[0003] In the related art, the upper and lower walls of a fault are researched to determine the sedimentary range of a far-shore subaqueous fan.

[0004] However, the above method has low accuracy in identifying the development position of the fan root of the far-shore subaqueous fan on the section of the fault, which affects the identification of the distribution characteristics of the far-shore subaqueous fan and the success rate of the exploration of the far-shore subaqueous fan. SUMMARY

[0005] The embodiments of the present disclosure provide a method, device, equipment and storage medium for determining a far-shore subaqueous fan, which can effectively identify the fan root, fan middle and fan end subfacies of the far-shore subaqueous fan. The technical solution is as follows:

[0006] In one aspect, a method for determining a far-shore subaqueous fan is provided, including: determining a source direction of the far-shore subaqueous fan; determining a development position of a fan root of the far-shore subaqueous fan on a section of a fault according to a paleofall of the fault in a first stratum and the source direction, the first stratum being any one of the strata in which the fault is formed in different periods; determining a migration direction of a sand body according to a thickness of the first stratum of a downthrown wall of the fault; determining a planar distribution characteristic of a sandstone thickness of the first stratum of the downthrown wall of the fault; and determining a distribution characteristic of the far-shore subaqueous fan according to the development position of the fan root on the section of the fault, the migration direction of the sand body and the planar distribution characteristic.

[0007] Optionally, the determining of the source direction of the far-shore subaqueous fan includes: obtaining mineral distribution characteristics of a plurality of wells near the fault in the first stratum; determining wells having the same source category as the wells including the same target mineral species and content distribution characteristic; and determining the source direction of the far-shore subaqueous fan according to the wells having the same source category.

[0008] Optionally, the determining the development position of the fan root of the distal subaqueous fan on the fault surface according to the paleo-relief of the fault in the first stratum and the provenance direction comprises: selecting a plurality of seismic profiles perpendicular to the extension direction of the fault on a structural plan of the oilfield, obtaining the thickness of the first stratum of a first point on the hanging wall of the fault in each seismic profile and the thickness of the first stratum of a second point on the foot wall of the fault, the first point being a sampling point of the first stratum of the hanging wall of the fault near the fault surface in the seismic profile, and the second point being a sampling point of the first stratum of the foot wall of the fault near the fault surface in the seismic profile; and determining the paleo-relief of the fault at the plurality of seismic profiles according to the difference between the thickness of the first stratum of the first point on the hanging wall of the fault and the thickness of the first stratum of the second point on the foot wall of the fault.

[0009] Optionally, the method further comprises: determining the location of the paleo-gully according to the paleo-relief; and determining the location of the paleo-gully overlapping with the provenance direction as the development position of the fan root of the distal subaqueous fan on the fault surface.

[0010] Optionally, the determining the migration direction of the sand body according to the thickness of the first stratum of the foot wall of the fault comprises: pointing from the direction with small thickness of the first stratum of the foot wall to the direction with large thickness of the first stratum of the foot wall as the migration direction of the sand body.

[0011] In another aspect, a device for determining a distal subaqueous fan is provided, comprising: a first determining module configured to determine a provenance direction of the distal subaqueous fan; a second determining module configured to determine a development position of a fan root of the distal subaqueous fan on a fault surface according to a paleo-relief of the fault in a first stratum and the provenance direction, the first stratum being any stratum in which the fault is formed in different periods; a third determining module configured to determine a migration direction of a sand body according to a thickness of the first stratum of a foot wall of the fault; a fourth determining module configured to determine a planar distribution feature of a sandstone thickness of the first stratum of the foot wall of the fault; and a fifth determining module configured to determine a distribution feature of the distal subaqueous fan according to the development position of the fan root on the fault surface, the migration direction of the sand body, and the planar distribution feature.

[0012] Optionally, the second determining module is configured to select a plurality of seismic profiles perpendicular to the extension direction of the fault on a field structure plan, obtain the thickness of the first stratum of a first point in the hanging wall of the fault in each of the seismic profiles and the thickness of the first stratum of a second point in the foot wall of the fault, the first point being a sampling point of the first stratum in the hanging wall of the fault near the section in the seismic profile, and the second point being a sampling point of the first stratum in the foot wall of the fault near the section in the seismic profile; determine the paleo-drop of the fault at the plurality of seismic profiles according to the difference between the thickness of the first stratum of the first point in the hanging wall of the fault and the thickness of the first stratum of the second point in the foot wall of the fault; determine the location of the paleo-gully according to the paleo-drop; and determine the development location of the root of the far-shore subaqueous fan on the section of the fault as the location of the paleo-gully overlapping the source direction.

[0013] In another aspect, a device for determining a far-shore subaqueous fan is provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to execute the foregoing method for determining a far-shore subaqueous fan.

[0014] In another aspect, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, the computer program being executed by a processor to implement the foregoing method for determining a far-shore subaqueous fan.

[0015] In another aspect, a computer program product is provided, comprising computer programs / instructions, the computer programs / instructions being executed by a processor to implement the foregoing method for determining a far-shore subaqueous fan.

[0016] The technical scheme provided by the embodiments of the present disclosure has the following beneficial effects:

[0017] In the embodiments of the present disclosure, the development location of the root of the far-shore subaqueous fan on the section of the fault is determined according to the paleo-drop of the fault and the source direction, and the distribution characteristics of the far-shore subaqueous fan are determined according to the development location of the root of the far-shore subaqueous fan on the section of the fault, the migration direction of the sand body, and the planar distribution characteristics of the sandstone thickness of the foot wall of the fault in the first stratum, so that the root, the middle and the end of the far-shore subaqueous fan can be more accurately identified, the distribution direction and the distribution range of the far-shore subaqueous fan can be determined, and the exploration success rate of the far-shore subaqueous fan can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the embodiments description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0019] Figure 1 is a flow chart of a method for determining a distal subaqueous fan provided by an embodiment of the present disclosure;

[0020] Figure 2 is a flow chart of another method for determining a distal subaqueous fan provided by an embodiment of the present disclosure;

[0021] Figure 3 is a schematic diagram of heavy mineral content provided by an embodiment of the present disclosure;

[0022] Figure 4 is a schematic diagram of a source direction and a selected seismic profile provided by an embodiment of the present disclosure;

[0023] Figure 5 is a schematic diagram of a seismic profile provided by an embodiment of the present disclosure;

[0024] Figure 6 is a paleofall fold line diagram of a fault provided by an embodiment of the present disclosure;

[0025] Figure 7 is a plan view of the thickness of the first stratum of the downthrown side of the fault provided by an embodiment of the present disclosure;

[0026] Figure 8 is a plan view of the sandstone thickness of the first stratum of the downthrown side of the fault provided by an embodiment of the present disclosure;

[0027] Figure 9 is a block diagram of a device for determining a distal subaqueous fan provided by an embodiment of the present disclosure;

[0028] Figure 10 is a block diagram of an apparatus for determining a distal subaqueous fan provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] In order to make the purposes, technical solutions and advantages of the present disclosure clearer, the embodiments of the present disclosure will be further described in detail below with reference to the drawings.

[0030] Unless otherwise defined, technical terms or scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terms "first", "second", "third", and the like, as used in the description and the claims herein, do not have any quantitatively meaning or significance, but are used only to distinguish one element from another. Similarly, the terms "one", "another", and the like, do not have any quantitatively meaning or significance, but are used only to distinguish one element from another. The terms "include", "comprise", and the like, mean that the elements listed after the terms "include", "comprise", and the like, encompass the elements listed and equivalents thereof, and do not exclude other elements. The terms "connected", "coupled", and the like, do not have any quantitatively meaning or significance, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", "top", "bottom", and the like, are used only to indicate relative positions, and can change when the absolute positions of the described objects change. In addition, the term "and / or" in the specification and the claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the front and rear associated objects.

[0031] Figure 1 is a flowchart of a method for determining a distal offshore subaqueous fan according to an embodiment of the present disclosure. As shown in Figure 1 , the method comprises:

[0032] Step S101: determining a source direction of the distal offshore subaqueous fan.

[0033] Step S102: determining a development position of a fan root of the distal offshore subaqueous fan on a fault surface of a fault according to a paleo-relief of a first stratum and the source direction.

[0034] The first stratum is any one of the strata in which the fault is formed in different periods.

[0035] Step S103: determining a migration direction of a sand body according to a thickness of the first stratum of a downthrown side of the fault.

[0036] Step S104: determining a planar distribution feature of a sandstone thickness of the first stratum of the downthrown side of the fault.

[0037] Step S105: determining a distribution feature of the distal offshore subaqueous fan according to the development position of the fan root on the fault surface, the migration direction of the sand body, and the planar distribution feature.

[0038] In the embodiments of the present disclosure, the development position of the fan root of the distal underwater fan on the fault surface is determined according to the paleo-relief of the fault and the source direction, and the distribution characteristics of the distal underwater fan are determined according to the development position of the fan root on the fault surface, the migration direction of the sand body, and the planar distribution characteristics of the sandstone thickness of the downthrown side of the fault in the first stratum, so that the fan root, the fan middle and the fan end subfacies of the distal underwater fan can be more accurately identified, the distribution direction and the distribution range of the distal underwater fan can be determined, and the exploration success rate of the distal underwater fan can be improved.

[0039] Figure 2 is a flowchart of another method for determining a distal underwater fan provided by the embodiments of the present disclosure. As shown in Figure 2 , the method comprises:

[0040] Step S201: Obtain the mineral distribution characteristics of a plurality of wells near the fault in the first stratum.

[0041] The fault is a sediment-controlling fault, the sediment-controlling fault is a long-term active fault with large vertical fault throw and large lateral extension, and the distal underwater fan can be formed in the sediment-controlling fault.

[0042] There are a plurality of strata near the fault, and different strata are formed in different periods. The first stratum can be any one of the strata near the fault.

[0043] Exemplarily, the strata near the fault can be divided in the following manner:

[0044] The plurality of wells near the fault are divided into standard wells and non-standard wells. The standard well is a well in which different strata have been divided by a geologist according to the stratum division standard, and the non-standard well is a well to be divided into different strata. The logging curve and the lithology data of each well are obtained, and the logging curve and the lithology data of the non-standard well are compared with the logging curve and the lithology data of the standard well, and the non-standard well is divided into different strata corresponding to the strata of the standard well by using the similarity or correlation.

[0045] After the strata division of the plurality of wells near the fault is completed, a stratum formed in the same period is selected as the first stratum, and then the mineral distribution characteristics of the plurality of wells in the first stratum are obtained.

[0046] Exemplarily, the standard well can be previously divided into a Sha-1 upper layer, a Sha-1 middle layer and a Sha-1 lower layer, the Sha-1 upper layer has a top depth of 2000 m and a bottom depth of 2025 m, the Sha-1 middle layer has a top depth of 2025 m and a bottom depth of 2050 m, and the Sha-1 lower layer has a top depth of 2050 m and a bottom depth of 2080 m. The non-standard well can also be divided into the Sha-1 lower layer, the Sha-1 middle layer and the Sha-1 upper layer by using the similarity or correlation between the logging curves and lithology data of the non-standard well and the logging curves and lithology data of the standard well. For example, the Sha-1 lower layer can be selected as the first layer, and of course other layers can also be selected as the first layer, which is not limited in the present disclosure.

[0047] The mineral distribution feature is used to indicate the kind and content distribution of the target mineral.

[0048] The target mineral can be a heavy mineral or a light mineral. The heavy mineral refers to a terrigenous clastic mineral with a specific gravity greater than 2.9, and the light mineral refers to a terrigenous clastic mineral with a specific gravity less than 2.9. The kinds of the heavy mineral include zircon, tourmaline, rutile, garnet, magnetite, etc., and the kinds of the light mineral include quartz, feldspar, rock debris, etc.

[0049] The content distribution of the target mineral refers to the high-low order of the content of various target minerals. For example, the target mineral is a heavy mineral, and the content of the heavy mineral from high to low is zircon, garnet and magnetite, which is considered as one kind of content distribution, and if the content of the heavy mineral from high to low is garnet, zircon and magnetite, which is considered as another kind of content distribution.

[0050] Each well has a plurality of sampling points arranged along the well depth direction in the first layer, and in this step S201, when the kind of the target mineral obtained from the plurality of sampling points is the same and the content distribution of the target mineral is the same, the data obtained from one of the sampling points can be selected as the mineral distribution feature of the well in the first layer.

[0051] When the kind of the target mineral obtained from the plurality of sampling points is different or the content distribution of the target mineral is different, it indicates that the well is controlled by multiple sources, and the data obtained from a plurality of representative sampling points can be selected as the mineral distribution feature of the well. Here, the representative sampling points can be determined in the following way: first, classify the plurality of sampling points according to the kind of the target mineral and the content distribution of the target mineral, the sampling points in the same class have the same kind of target mineral and the same content distribution of the target mineral; and then, select one sampling point from each class of sampling points as a representative sampling point, or select one sampling point from each class of sampling points containing a number greater than a set value as a representative sampling point. The set value can be 1 or 2, etc., which can be set according to actual conditions.

[0052] Figure 3This is a schematic diagram illustrating the content of heavy minerals according to an embodiment of this disclosure. For example... Figure 3 As shown, a well has four sampling points spaced along its depth in the first formation: sampling point 1, sampling point 2, sampling point 3, and sampling point 4. The heavy minerals at all four sampling points include zircon, tourmaline, rutile, garnet, and magnetite. The heavy mineral content distribution at sampling points 1 and 2, from highest to lowest, is zircon, tourmaline, rutile, garnet, and magnetite. Similarly, the heavy mineral content distribution at sampling points 3 and 4, from highest to lowest, is garnet, zircon, tourmaline, rutile, and magnetite. Therefore, data from either sampling point 1 or 2 can be selected as the distribution of one target mineral species in the first formation, and data from either sampling point 3 or 4 can be selected as the distribution of another target mineral species in the first formation. For example, data from sampling points 1 and 3 can be selected as the mineral distribution characteristics of the well, meaning that the mineral distribution characteristics include the distribution of two target mineral species and their contents.

[0053] Step S202: Wells whose mineral distribution characteristics include the same target mineral type and content distribution are identified as wells with the same source category.

[0054] When multiple wells have the same type of target mineral in the first formation and the same distribution of the target mineral content, these wells can be identified as wells with the same source category.

[0055] If the mineral distribution characteristics of the same well include multiple target mineral types or multiple target mineral content distributions, it indicates that the well has multiple source categories. If the source category of the well also exists in other wells, these wells can be identified as having the same source category.

[0056] The following example illustrates the distribution of heavy minerals in the first stratum from multiple wells.

[0057] When the types of heavy minerals in both the first and second wells include zircon, tourmaline, rutile, garnet, and magnetite, and the distribution of heavy mineral content from high to low is zircon, rutile, tourmaline, garnet, and magnetite, then the first and second wells can be identified as having the same source category.

[0058] When the types of the heavy minerals in the third well and the fourth well include zircon, tourmaline, rutile, garnet and magnetite, two different content distribution situations of target minerals are obtained in different sampling points of the third well, the first one is that the content distribution of the heavy minerals is in the order of zircon, rutile, tourmaline, garnet and magnetite from high to low, and the second one is that the content distribution of the heavy minerals is in the order of garnet, zircon, tourmaline, rutile and magnetite from high to low, and the content distribution of the heavy minerals in the fourth well is in the order of garnet, zircon, tourmaline, rutile and magnetite from high to low. At this time, the first well, the second well and the third well can be determined as wells with the same source category, and the third well and the fourth well can also be determined as wells with the same source category.

[0059] Step S203: determining the source direction of the distal subaqueous fan according to the wells with the same source category.

[0060] In this step S203, the wells with the same source category in adjacent positions can be divided together by an envelope line on a field structure plan, the field structure plan is used to describe the underground structure characteristics of the oilfield, and the source direction of the distal subaqueous fan is directed from the upthrown side of the fault to the downthrown side of the fault within the envelope line range on the plane.

[0061] Figure 4 is a schematic diagram of the source direction and the selected seismic profile provided by the embodiment of the present disclosure. Figure 4 The envelope line includes a first envelope line 10, a second envelope line 11, a third envelope line 12 and a fourth envelope line 13, and the circles in the envelope line represent wells. The types of the heavy minerals in the wells within the four envelope line ranges are zircon, garnet and magnetite. Among them, in the wells within the first envelope line 10 range and the third envelope line 12 range, the content distribution of the heavy minerals is in the order of garnet, zircon and magnetite from high to low; in the wells within the second envelope line 11 range and the fourth envelope line 13 range, the content distribution of the heavy minerals is in the order of zircon, garnet and magnetite from high to low, that is, the wells within the first envelope line 10 range and the third envelope line 12 range have the same source category, and the wells within the second envelope line 11 range and the fourth envelope line 13 range have the same source category. Within the four envelope line ranges, the source direction of the distal subaqueous fan is directed from the upthrown side of the fault to the downthrown side of the fault.

[0062] In some examples, the same well has multiple source categories, and the well can be divided into multiple envelope ranges. For example, a well has two source categories, and the species of heavy minerals in the well include zircon, garnet and magnetite. Two different content distribution conditions of target minerals are obtained from different sampling points in the well, the first one is that the content distribution of heavy minerals from high to low is garnet, zircon and magnetite, and the second one is that the content distribution of heavy minerals from high to low is zircon, garnet and magnetite. Then, according to the source categories of the well and its adjacent wells, the well can be divided into the first envelope 10 or the third envelope 12 range, and the well can also be divided into the second envelope 11 or the fourth envelope 13 range.

[0063] Through steps S201 to S203, the source direction of the offshore subaqueous fan can be determined, so as to preliminarily identify the distribution direction and range of the offshore subaqueous fan.

[0064] Step S204: selecting multiple seismic profiles perpendicular to the extension direction of the fault on the oilfield structure plane, and obtaining the thickness of the first stratum of the first point in the hanging wall of the fault and the thickness of the first stratum of the second point in the foot wall of the fault in each seismic profile.

[0065] In the formula, the first point is a sampling point of the first stratum of the hanging wall of the fault near the section in the seismic profile, and the second point is a sampling point of the first stratum of the foot wall of the fault near the section in the seismic profile. In the seismic profile, a plumb line is drawn along the first point and the second point respectively, the plumb line of the first point intersects with the top and bottom interfaces of the first stratum of the hanging wall, and the plumb line of the second point intersects with the top and bottom interfaces of the first stratum of the foot wall.

[0066] Figure 5 is a schematic diagram of a seismic profile provided by an embodiment of the present disclosure. As shown in Figure 5 The rock mass above the section 20 is the hanging wall 21, and the rock mass below the section 20 is the foot wall 22. The hanging wall 21 and the foot wall 22 each include multiple strata. In terms of relative displacement direction, the upward relative of the fault is the hanging wall, and the downward relative is the foot wall. Figure 5 D1 is the thickness of the first stratum of the hanging wall 21 of the fault at the first point in the seismic profile, which can also be referred to as the thickness of the first stratum of the foot wall of the fault at the first point in the seismic profile; and D2 is the thickness of the first stratum of the foot wall 22 of the fault at the second point in the seismic profile, which can also be referred to as the thickness of the first stratum of the hanging wall of the fault at the second point in the seismic profile.

[0067] In this step S204, a plurality of seismic profiles can be selected on the oilfield structure plan along the extension direction of the fault, which are equal in interval and parallel to each other and perpendicular to the extension direction of the fault. Since the extension direction of the fault is not a straight line, the seismic profiles can also be selected approximately perpendicular to the extension direction of the fault, as shown in FIG. 2. Figure 4 As shown in FIG. 2, the seismic profiles can be selected along the arrow direction in FIG. 2. Figure 4

[0068] As shown in FIG. 2, the top and bottom seismic two-way reflection times of the first stratum of the hanging wall 21 of the fault at a first point on the profile and the top and bottom seismic two-way reflection times of the first stratum of the foot wall 22 of the fault at a second point on the profile are obtained. Figure 5

[0069] H = 0.0000000141019945 * T 3 + 0.000119762957 * T 2 + 0.904809721 * T (1).

[0070] In formula (1), T represents the seismic two-way reflection time, and the unit is m; H represents the depth, and the unit is m. The seismic two-way reflection time T can be obtained from the seismic data.

[0071] According to formula (1), the top and bottom depths of the first stratum of the hanging wall 21 of the fault at the first point and the top and bottom depths of the first stratum of the foot wall 22 of the fault at the second point are obtained. Then, the thickness D1 of the first stratum of the hanging wall 21 of the fault at the first point and the thickness D2 of the first stratum of the foot wall 22 of the fault at the second point are also the difference between the corresponding top and bottom depths.

[0072] For example, a plurality of seismic profiles can be selected along the extension direction of the fault at an interval of 20 line numbers, which are parallel to each other and perpendicular to the extension direction of the fault. The line number represents the distance between the seismic lines, that is, the interval between the parallel arrows in FIG. 2 is 20 line numbers. Of course, the interval can be smaller or larger, and the present disclosure does not limit this. Figure 4

[0073] Step S205: determining the paleothrow of the fault at the plurality of seismic profiles according to the difference between the thickness of the first stratum of the hanging wall at the first point and the thickness of the first stratum of the foot wall at the second point.

[0074] The paleothrow refers to the thickness difference of the corresponding stratum of the hanging wall and the foot wall of the fault at a certain period. The paleothrow can reflect the activity degree of the fault at different periods.

[0075] ​​​As shown in the seismic profile in Figure 5 The difference between the thickness D1 of the first stratum of the hanging wall of the fault and the thickness D2 of the first stratum of the foot wall of the fault is the paleo-drop of the fault at the seismic profile.

[0076] Step S206: According to the paleo-drop, the position of the paleo-gully is determined.

[0077] According to the paleo-drop of the fault at multiple seismic profiles and the line number positions of the multiple seismic profiles, a paleo-drop broken line graph of the fault is established, according to the peak position in the broken line graph, between the peak and the trough, the position interval in which the difference between the paleo-drop near the peak and the paleo-drop of the peak is less than the target difference value is determined as the position of the paleo-gully. The line number position of the peak and the position near the peak are relatively strong in the activity of the fault, that is, the position in which the fault surface of the normal fault relatively rises and falls to a greater extent, which indicates that the paleo-gully is formed at these positions, so the line number position of the peak on the fault surface and the position near the peak can be determined as the position of the paleo-gully. Exemplarily, the target difference value can be 8m, of course, it can also be another difference value, which is not limited in the present disclosure.

[0078] Figure 6 is a paleo-drop broken line graph of a fault provided by an embodiment of the present disclosure. As shown in Figure 6 The horizontal coordinate represents the line number of the selected seismic profile, and the vertical coordinate represents the size of the paleo-drop, Figure 6 There are multiple peaks in the graph, between the peak and the trough, the position interval in which the difference between the paleo-drop near the peak and the paleo-drop of the peak is less than 8m is determined as the position of the paleo-gully, as shown in Figure 6 The positions of eight paleo-gullies can be determined.

[0079] Step S207: According to the position of the paleo-gully and the direction of the source, the development position of the fan root of the offshore subaqueous fan on the fault surface is determined.

[0080] For example, the position of the paleo-gully overlapping with the direction of the source is determined as the development position of the fan root of the offshore subaqueous fan on the fault surface.

[0081] Since the formation of the offshore subaqueous fan requires sufficient water depth, sufficient topographic slope angle, abundant source supply and certain triggering mechanism, not every paleo-gully will control the formation of the offshore subaqueous fan deposit as the fan root, therefore, according to the position of the paleo-gully, combined with the direction of the source of the offshore subaqueous fan, the position of the paleo-gully overlapping with the direction of the source can be determined as the development position of the fan root of the offshore subaqueous fan on the fault surface.

[0082] Through steps S204 to S207, the development position of the fan root of the offshore subaqueous fan on the fault surface can be effectively identified, so as to further identify the distribution range of the offshore subaqueous fan.

[0083] Step S208: Obtain the thickness of the first formation of the downthrown side of the fault.

[0084] In this step S208, the time domain data of the top and bottom boundaries of the first formation of the downthrown side of the fault can be obtained by using the seismic software, and the time domain data includes the seismic two-way reflection time. Since the seismic data is used to interpret the seismic profile by a certain interval of trace number and line number, the obtained time domain data needs to be interpolated, that is, encrypted, and then the depth domain data of the top and bottom boundaries of the first formation of the downthrown side of the fault is obtained according to formula (1). Then the thickness of the first formation of the downthrown side of the fault is the difference between the depth of the bottom boundary and the depth of the top boundary.

[0085] Step S209: Determine the migration direction of the sand body according to the thickness of the first formation of the downthrown side of the fault.

[0086] The migration direction of the sand body is from the direction with small thickness of the first formation of the downthrown side to the direction with large thickness of the first formation of the downthrown side.

[0087] The greater the thickness of the first formation of the downthrown side, the lower the ancient landform terrain, and the smaller the thickness of the first formation of the downthrown side, the higher the ancient landform terrain. From the direction with high terrain to the direction with low terrain, it indicates that the ancient structure is a depression, which is a good sedimentary space and is conducive to the migration and deposition of sand bodies. Therefore, according to the thickness of the first formation of the downthrown side of the fault, the migration direction of the sand body can be determined.

[0088] Figure 7 is a plan view of the thickness of the first formation of the downthrown side of the fault provided by the embodiment of the present disclosure. As shown in Figure 7 different shades of different colors represent different thicknesses of the first formation of the downthrown side, Figure 7 the arrow direction in is from the direction with small thickness of the first formation of the downthrown side to the direction with large thickness of the first formation of the downthrown side, that is, the migration direction of the sand body is indicated.

[0089] Through steps S208 to S209, the migration direction of the sand body can be effectively identified, so as to preliminarily identify the fan middle and fan end subfacies of the distal subaqueous fan, and further determine the distribution direction and range of the distal subaqueous fan.

[0090] Step S210: Obtain the sandstone thickness of the first formation of the downthrown side of the fault at multiple wells.

[0091] In this step S210, the sandstone thickness of the first formation of the downthrown side of the fault can be obtained according to the logging curve characteristics of the multiple wells corresponding to the downthrown side of the fault.

[0092] Step S211: determining the planar distribution feature of the sandstone thickness of the first formation in the downthrown wall of the fault according to the sandstone thickness of the first formation in the downthrown wall of the fault at multiple wells.

[0093] The planar distribution feature refers to the distribution of the sandstone thickness of the first formation in the downthrown wall of the fault at different positions in the plane.

[0094] Figure 8 is a planar graph of the sandstone thickness of the first formation in the downthrown wall of the fault provided by the embodiment of the present disclosure. As shown in Figure 8 , different colors are used to represent different sandstone thicknesses of the first formation in the downthrown wall. The sandstone thickness in the fan mid 301 is larger, and the sandstone thickness in the fan end 302 is smaller. Therefore, according to the distribution of the sandstone thickness at different positions in the plane, the fan mid 301 and the fan end 302 subfacies of the distal subaqueous fan can be clearly identified.

[0095] Through steps S210 to S211, the fan mid and fan end subfacies of the distal subaqueous fan can be clearly and accurately identified, and the distribution range of the distal subaqueous fan is determined again.

[0096] Step S212: determining the distribution feature of the distal subaqueous fan according to the development position of the fan root on the fault surface, the sand body migration direction, and the planar distribution feature of the sandstone thickness of the downthrown wall of the fault.

[0097] The distribution feature of the distal subaqueous fan includes the fan root, fan mid, and fan end subfacies. The development position of the fan root is determined, that is, the triggering position of the distal subaqueous fan is determined. According to the sand body migration direction and the planar distribution feature of the sandstone thickness of the downthrown wall of the fault, the fan mid and fan end subfacies of the distal subaqueous fan can be further effectively identified. Therefore, the determined fan root, fan mid, and fan end subfacies are combined in the plane, and the distribution direction and distribution range of the distal subaqueous fan can be clearly and accurately determined.

[0098] Figure 9 is a block diagram of a device for determining a distal subaqueous fan provided by the embodiment of the present disclosure. As shown in Figure 9 , the device 1000 for determining the distal subaqueous fan includes a first determination module 1001, a second determination module 1002, a third determination module 1003, a fourth determination module 1004, and a fifth determination module 1005.

[0099] The first determining module 1001 is configured to determine a source direction of the distal subaqueous fan. The second determining module 1002 is configured to determine a development position of a fan root of the distal subaqueous fan on a fault surface of a fault according to a paleo-drop of the fault in a first stratum and the source direction, the first stratum being any one of strata in which the fault is formed in different periods. The third determining module 1003 is configured to determine a migration direction of a sand body according to a thickness of the first stratum of a downthrown side of the fault. The fourth determining module 1004 is configured to determine a planar distribution feature of the sandstone thickness of the first stratum of the downthrown side of the fault. The fifth determining module 1005 is configured to determine a distribution feature of the distal subaqueous fan according to the development position of the fan root on the fault surface, the migration direction of the sand body and the planar distribution feature.

[0100] Optionally, the first determining module 1001 is configured to acquire mineral distribution features of a plurality of wells near the fault in the first stratum; determine wells with the same mineral distribution features including the same target mineral kind and content distribution as having the same source category; and determine the source direction of the distal subaqueous fan according to the wells having the same source category.

[0101] Optionally, the second determining module 1002 is configured to select a plurality of seismic profiles perpendicular to an extension direction of the fault on a field structure plane map, acquire a thickness of the first stratum of a first point in an upthrown side of the fault and a thickness of the first stratum of a second point in a downthrown side of the fault in each seismic profile, the first point being a sampling point of the first stratum of the upthrown side of the fault near the fault surface in the seismic profile, the second point being a sampling point of the first stratum of the downthrown side of the fault near the fault surface in the seismic profile; and determine the paleo-drop of the fault at the plurality of seismic profiles according to a difference between the thickness of the first stratum of the upthrown side of the fault at the first point and the thickness of the first stratum of the downthrown side of the fault at the second point in the plurality of seismic profiles.

[0102] Optionally, the second determining module 1002 is configured to determine a location of a paleo-gully according to the paleo-drop; and determine the location of the paleo-gully overlapping with the source direction as the development position of the fan root of the distal subaqueous fan on the fault surface.

[0103] Optionally, the third determining module 1003 is configured to point from a direction in which the thickness of the first stratum of the downthrown side is small to a direction in which the thickness of the first stratum of the downthrown side is large as the migration direction of the sand body.

[0104] It should be noted that the device 1000 for determining a distal underwater fan provided in the above embodiment is only used as an example for the division of the above functional modules in determining the distal underwater fan, and in actual application, the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the device for determining a distal underwater fan and the method for determining a distal underwater fan provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0105] Figure 10 is a block diagram of a device for determining a distal underwater fan provided in the embodiments of the present disclosure. As shown in the figure, the device 2000 for determining a distal underwater fan includes a processor 2001 and a memory 2002. The device 2000 for determining a distal underwater fan can be a computer device or other types of devices. Figure 10

[0106] The processor 2001 can include one or more processing cores, such as a 5-core processor, an 8-core processor, etc. The processor 2001 can be implemented in at least one of a hardware form of a digital signal processing (DSP), a field-programmable gate array (FPGA), a programmable logic array (PLA). The processor 2001 can also include a main processor and a coprocessor. The main processor is a processor for processing data in an awake state, also known as a central processing unit (CPU); the coprocessor is a low-power processor for processing data in a standby state. In some embodiments, the processor 2001 can be integrated with a graphics processor (GPU), which is used to render and draw the content required by the display screen. In some embodiments, the processor 2001 can also include an artificial intelligence (AI) processor, which is used to process machine learning-related computing operations.

[0107] ​The memory 2002 can include one or more computer-readable storage media. The computer-readable storage media can be non-transitory. The memory 2002 can also include high-speed random access memory and can include non-volatile memory, such as one or more magnetic disk storage devices, optical storage devices, flash memory devices, or other non-volatile solid-state storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 2002 is used to store at least one instruction for execution by the processor 2001 to implement the method for determining a distal subaqueous fan.

[0108] Those skilled in the art can understand that the structure shown in the above embodiments is not a limitation on the device 2000 for determining a distal subaqueous fan, and the device 2000 for determining a distal subaqueous fan can include more or fewer components than those shown in the figure, or combine certain components, or adopt a different arrangement of components. Figure 10

[0109] Exemplarily, a non-transitory computer-readable storage medium including instructions is also provided, for example, the memory 2002 including instructions, which can be executed by the processor 2001 of the device 2000 for determining a distal subaqueous fan to implement the method for determining a distal subaqueous fan. For example, the non-transitory computer-readable storage medium can be a read-only memory, a random access memory, an optical disc, a magnetic tape, a floppy disk, an optical data storage device, and the like.

[0110] Exemplarily, a computer program product is also provided, including a computer program / instruction, which, when executed by a processor, implements the method for determining a distal subaqueous fan provided in the embodiments of the present disclosure.

[0111] The above description is not intended to limit the present disclosure in any form, although the present disclosure has been disclosed as above through embodiments. However, any person skilled in the art can make some minor changes or modifications to the above-mentioned disclosed technical content as equivalent embodiments without departing from the technical solution of the present disclosure, as long as the changes or modifications do not depart from the technical solution of the present disclosure. Any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present disclosure are still within the scope of the technical solution of the present disclosure.​

Claims

1. A method of determining a distal offshore subaqueous fan, characterized by, The method comprises: determining a source direction of a distal subaqueous fan; determining a development position of a fan root of the distal subaqueous fan on a fault surface of a fault according to a paleo-drop of the fault in a first stratum and the source direction, the first stratum being any one of strata in which the fault is formed in different periods; determining a migration direction of a sand body according to a thickness of the first stratum of a downthrown side of the fault; determining a planar distribution feature of sandstone thickness of the first stratum of the downthrown side of the fault; determining a distribution feature of the distal subaqueous fan according to the development position of the fan root on the fault surface of the fault, the migration direction of the sand body and the planar distribution feature; the determining the development position of the fan root of the distal subaqueous fan on the fault surface of the fault according to the paleo-drop of the fault in the first stratum and the source direction comprises: selecting a plurality of seismic profiles perpendicular to an extension direction of the fault on a structural plane map of an oilfield, obtaining a thickness of the first stratum of a first point in an upthrown side of the fault in each of the seismic profiles and a thickness of the first stratum of a second point in a downthrown side of the fault, the first point being a sampling point of the first stratum of the upthrown side of the fault near the fault surface in the seismic profile, the second point being a sampling point of the first stratum of the downthrown side of the fault near the fault surface in the seismic profile; determining a paleo-drop of the fault at the plurality of seismic profiles according to a difference between the thickness of the first stratum of the upthrown side of the fault at the first point and the thickness of the first stratum of the downthrown side of the fault at the second point in the plurality of seismic profiles; determining a position of a paleo-gully according to the paleo-drop; determining the position of the paleo-gully overlapping with the source direction as the development position of the fan root of the distal subaqueous fan on the fault surface of the fault.

2. The method of determining a distal offshore subaqueous fan of claim 1, wherein, The determining the source direction of the distal subaqueous fan comprises: obtaining a mineral distribution feature of the first stratum of a plurality of wells near the fault; determining wells with the same mineral distribution feature as wells with the same source category; determining the source direction of the distal subaqueous fan according to the wells with the same source category.

3. The method of determining a distal offshore subaqueous fan of claim 1, wherein, The determining the migration direction of the sand body according to the thickness of the first stratum of the downthrown side of the fault comprises: pointing from a direction with a small thickness of the first stratum of the downthrown side to a direction with a large thickness of the first stratum of the downthrown side as the migration direction of the sand body.

4. An apparatus for determining a distal offshore subaqueous fan, characterized by, The method comprises: a first determining module configured to determine a source direction of a distal subaqueous fan; a second determining module configured to determine a development position of a fan root of the distal subaqueous fan on a fault surface of a fault according to a paleo-drop of the fault in a first stratum and the source direction, the first stratum being any one of strata in which the fault is formed in different periods; a third determining module configured to determine a migration direction of a sand body according to a thickness of the first stratum of a downthrown side of the fault; a fourth determining module configured to determine a planar distribution feature of sandstone thickness of the first stratum of the downthrown side of the fault; a fifth determining module configured to determine the distribution feature of the distal subaqueous fan according to the development position of the fan root on the fault surface, the migration direction of the sand body, and the planar distribution feature; the second determining module is configured to select a plurality of seismic profiles perpendicular to the extension direction of the fault on a structural plane map of an oilfield, obtain the thickness of a first stratum at a first point in the hanging wall of the fault and the thickness of the first stratum at a second point in the foot wall of the fault in each of the seismic profiles, the first point being a sampling point of the first stratum in the hanging wall of the fault near the fault surface in the seismic profile, and the second point being a sampling point of the first stratum in the foot wall of the fault near the fault surface in the seismic profile; determine the paleo-fall of the fault at the plurality of seismic profiles according to the difference between the thickness of the first stratum at the first point in the hanging wall of the fault and the thickness of the first stratum at the second point in the foot wall of the fault in the plurality of seismic profiles; determine the location of the paleo-gully according to the paleo-fall; and determine the development position of the fan root of the distal subaqueous fan on the fault surface as the location of the paleo-gully overlapping the provenance direction.

5. An apparatus for determining a distal offshore subaqueous fan, characterized by, comprise: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to perform the method for determining a distal subaqueous fan according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The computer program is stored in the computer readable storage medium, and the computer program is executed by the processor to realize the method for determining a distal subaqueous fan according to any one of claims 1 to 3.

7. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instructions are executed by the processor to realize the method for determining a distal subaqueous fan according to any one of claims 1 to 3.

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