Hydrodynamic quantitative evaluation method based on land frame sand ridge morphology

Abstract

The invention discloses a hydrodynamic force quantitative evaluation method based on land frame sand ridge morphology. The method comprises the following steps: acquiring related data for supporting land frame sand ridge characteristic characterization of a target work area; carrying out sand body seismic horizon interpretation; dividing a land frame sand ridge of a target layer into different system domains; carrying out correlation analysis on the seismic attributes and the sand body thickness, preferably selecting the seismic attributes and depicting a strip sand sedimentary facies; carrying out statistics on related physical property parameters of land frame sand ridges; carrying out statistics on land frame sand ridge morphology parameters of different system domains; classifying the land frame sand ridge morphology according to different system domains; hydrodynamic indexes of different system domains are calculated according to topographic features of land frame sand ridges; and according to the morphology type of the land frame sand ridge morphology and the hydrodynamic indexes of the different system domains, determining hydrodynamic influence types of the different system domains. According to the method, the hydrodynamic indexes formed by the land frame sand ridges in the different system domains are defined by representing the plane morphology parameters of the land frame sand ridges in the different system domains, and the subsequent exploration and development progress of lithologic oil and gas reservoirs can be boosted.

Description

Technical Field

[0001] The present invention relates to a hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges, belonging to the technical field of oil exploration and development. Background Art

[0002] The exploration and discovery of structural hydrocarbon reservoirs are becoming fewer and fewer, and lithologic hydrocarbon reservoirs such as updip pinch-out of sand bodies and lenticular bodies are gradually becoming important exploration targets for the growth of oil and gas reserves in China. On the shallow sea shelf dozens or hundreds of kilometers offshore, sand bodies with linear or radial planar shapes are often distributed, and these sand bodies are called shelf sand ridges (tidal sand ridges or beach ridges or ribbon sands). Most shelf sand ridges are distributed along the direction parallel to the shoreline, and are often wrapped by shelf mudstones to form lenticular lithologic traps, which are matched and communicated with the lower source rocks through faults or sand body networks, and have superior oil and gas accumulation conditions, and are important targets for lithologic exploration and development in China.

[0003] However, during the formation process of shallow sea shelf sand ridges, they are long-term affected by complex hydrodynamic gravitational forces, including tides or alongshore currents, etc. The shallow sea shelf mixed hydrodynamic process is complex, there are differences in hydrodynamic forces in different periods in the same area, and the hydrodynamic transformation intensities suffered by different facies belts in the same period are also different. This results in characteristics such as rapid changes in the morphology and lateral phase changes of shelf sand ridges, leading to strong heterogeneity in reservoir thickness and physical properties, and extremely large differences in oil (gas) content. For a long time, the method for evaluating the hydrodynamic influence of shelf sand ridges mainly relies on the bedding analysis recorded by cores. However, during the process of offshore oil and gas exploration, drilling and coring are often lacking, and it is difficult to accurately determine the types of hydrodynamic influence and evaluation methods, which greatly increases the difficulty of exploration and evaluation of such lithologic traps. Summary of the Invention

[0004] The purpose of the present invention is to provide a hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges in view of the problems existing in the prior art.

[0005] The technical solution provided by the present invention to solve the above technical problems is: a hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges, including the following steps:

[0006] Step S10: Obtain relevant data for characterizing the features of shelf sand ridges in the target work area;

[0007] Step S20: Based on the seismic data of the target work area and relying on the shelf sand ridge horizon interpretation scheme, carry out seismic horizon interpretation of the sand body;

[0008] Step S30: Identify the sequence boundary and system tract interface according to the seismic reflection termination relationship and the accommodation space sequence method, and based on the identified interfaces, divide the target layer shelf sand ridges into different system tracts respectively;

[0009] Step S40: Constrained by the seismic horizons of sand bodies, extract various conventional seismic attributes, and based on well logging data and the Direct software module, extract the single-well sand body thickness; then conduct a correlation analysis between the seismic attributes and the sand body thickness, optimize the seismic attributes, and characterize the sedimentary facies of the ribbon sand.

[0010] Step S50: Based on core and thin section data, constrained by the system tract division scheme, count the lithologies of the shelf sand ridges according to different system tracts.

[0011] Step S60: Based on physical property data and constrained by the system tract division scheme, count the physical property parameters related to the shelf sand ridges according to different system tracts.

[0012] Step S70: Based on the characterized sedimentary microfacies, use CorelDraw software and VB to write programs to count the morphological parameters of the shelf sand ridges in different system tracts.

[0013] Step S80: Comprehensively analyze the counted morphological parameters of the shelf sand ridges, and classify the morphologies of the shelf sand ridges according to different system tracts.

[0014] Step S90: According to the morphological characteristics of the shelf sand ridges, calculate the hydrodynamic indices of different system tracts.

[0015] Step S100: Determine the hydrodynamic influence types of different system tracts according to the morphological types of the shelf sand ridges and the hydrodynamic indices of different system tracts.

[0016] A further technical solution is that the relevant data includes seismic data, well logging data, core / thin section data, physical property data, and regional geological data.

[0017] A further technical solution is that when interpreting the seismic horizons of sand bodies in Step S20, follow the principles of isochronous correlation, hierarchical control, and model guidance, adopt the well-seismic joint method, and interact between plane and profile to achieve the closed interpretation of sand body horizons.

[0018] A further technical solution is that the specific process of Step S30 includes:

[0019] Step S31: Identify the sequence boundaries according to the seismic reflection termination relationships and sequence stratigraphy theories and methods.

[0020] Step S32: Identify the system tract boundaries according to the seismic reflection termination relationships and the accommodation space sequence method.

[0021] Step S33: Divide the different system tracts to which the shelf sand ridges belong according to the sequence boundaries and system tract boundaries.

[0022] A further technical solution is that the specific process of Step S40 includes:

[0023] Step S41: With the seismic horizons of sand bodies as constraints, extract various conventional seismic attributes including amplitude attributes, statistical attributes, signal attributes, and waveform attributes.

[0024] Step S42: Based on well logging data, use the Diret software module to extract the single-well sand body thickness of the target layer.

[0025] Step S43: Conduct a correlation analysis between the extracted seismic attributes and the sand body thickness, and optimize the seismic attributes.

[0026] Step S44: According to the optimized seismic attributes, and in combination with well logging, core, and sand body thickness data, characterize the shelf sand ridge sedimentary facies.

[0027] A further technical solution is that the physical property parameters of the shelf sand ridge in step S60 include porosity and permeability.

[0028] A further technical solution is that the morphological parameters of the shelf sand ridge in step S70 include length, maximum width, area, and strike.

[0029] A further technical solution is that the morphology of the shelf sand ridge in step S80 is divided into type I, type II, and type III; among them, type I is wider in the south and narrower in the north; type II has approximately equal width in the north and south; type III is slightly wider in the north and narrower in the south.

[0030] A further technical solution is that the calculation formula for the hydrodynamic index in step S90 is:

[0031]

[0032] In the formula: L1 is the maximum width value of the northern part of the ribbon sand body; L2 is the maximum width value of the southern part of the ribbon sand body; Δ is the hydrodynamic index.

[0033] A further technical solution is that in step S100, when the shape of the shelf sand ridge is type I, the hydrodynamic index Δ is 0.62 - 1.06, and its hydrodynamic influence type is mainly wave action;

[0034] When the shape of the shelf sand ridge is type II, the hydrodynamic index Δ is 0.06 - 0.2, and its hydrodynamic influence type is mainly tidal action;

[0035] When the shape of the shelf sand ridge is type III, the hydrodynamic index Δ is 0.25 - 0.53, and its hydrodynamic influence type is coastal current - tidal hybrid power.

[0036] The beneficial effects of the present invention: By characterizing the planar morphological parameters of the shelf sand ridges in different systems tracts, the present invention defines the hydrodynamic index for the formation of shelf sand ridges in different systems tracts, which can boost the exploration and development progress of subsequent lithologic oil and gas reservoirs. Description of the Drawings

[0037] Figure 1 It is a schematic diagram for identifying system tract interfaces by the seismic termination relationship and accommodation space sequence method;

[0038] Figure 2 It is a seismic profile and interface identification map of the target work area;

[0039] Figure 3 It is a schematic diagram for system tract division of the target work area;

[0040] Figure 4 It is a statistical chart of the thickness of shelf sand ridges in different system tracts;

[0041] Figure 5 It is a root mean square attribute map;

[0042] Figure 6 It is a sedimentary facies map of shelf sand ridges in the target work area;

[0043] Figure 7 It is a statistical chart of the lithology of shelf sand ridges in different system tracts;

[0044] Figure 8 It is a statistical chart of the physical properties of shelf sand ridges in different system tracts;

[0045] Figure 9 It is a statistical chart of the hydrodynamic index of shelf sand ridges in different system tracts. Detailed implementation manners

[0046] Next, the technical solution of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] As Figure 1 shown, a hydrodynamic quantitative evaluation method based on shelf sand ridge morphology provided by the present invention includes the following steps:

[0048] Step S10: Obtain relevant data for characterizing the features of shelf sand ridges in the target work area, where the relevant data includes seismic data, logging data, core / thin section data, physical property data, and regional geological data;

[0049] Step S20: Based on the seismic data of the target work area and according to the shelf sand ridge horizon interpretation scheme, carry out seismic horizon interpretation of the sand body;

[0050] Specifically, based on the shelf sand ridge horizon division scheme and referring to typical seismic reflection termination relationships (erosion, toplap, onlap, downlap), manually interpret and adjust the seismic horizons, and finally obtain a complete and closed three-dimensional seismic interpretation horizon.

[0051] When conducting seismic horizon interpretation, follow the principles of "isochronous correlation, hierarchical control, and model guidance", adopt the method of combining wells and seismic data, interact between the plane and the section, and achieve the closed interpretation of sand body horizons;

[0052] Step S30: According to the seismic reflection termination relationship and the accommodation space sequence method, identify the sequence boundaries and system tract boundaries, and based on the identified boundaries, divide the shelf sand ridges of the target layer into different system tracts respectively;

[0053] Step S31: According to the seismic reflection termination relationship and the theory and method of sequence stratigraphy, identify the sequence boundaries;

[0054] Apply the theory and method of sequence stratigraphy and the previous sequence division scheme for the target interval of the target work area to establish the basis for identifying sequence boundaries according to the seismic reflection characteristics of the target work area.

[0055] Sequence boundaries are generally unconformity surfaces, which will show seismic unconformity phenomena on seismic profiles. They can be judged by the reflection termination mode of seismic event axes on seismic profiles. Typical seismic unconformities include erosion, toplap, onlap, and downlap.

[0056] (1) Erosion

[0057] Erosion generally occurs at the top boundary of the sequence. The strata disappear laterally towards the top boundary of the sequence, and on the seismic profile, it is manifested as the seismic event axis terminating laterally towards the top boundary of the sequence, usually caused by erosion and tectonic fractures.

[0058] (2) Toplap

[0059] Toplap often occurs at the top boundary of the sequence, which means that the originally inclined strata reverse dip and gradually thin out until they disappear with the increase in the thickness of the sequence top boundary. On the seismic profile, it is manifested as the event axis below the interface gradually terminating tangentially at the interface, and the thickness of the stratigraphic unit below the interface varies greatly laterally. It is often associated with delta complexes and can also be seen in deep-sea sediment fans. Toplap is also evidence of sedimentary hiatus formed by non-deposition.

[0060] On seismic profiles, it is usually not easy to distinguish between erosion and toplap. The following are the differences between them:

[0061] 1. Toplap often appears at the top of the delta;

[0062] 2. The stratigraphic thickness reflected by toplap varies greatly in a small range, and the strata gradually disappear with the sequence top boundary; the stratigraphic thickness of erosion is often stable in a large range, and the event axes are approximately parallel to each other;

[0063] 3. Toplap is often associated with downlap;

[0064] (3) Onlap

[0065] The onlap phenomenon often appears at the base of a sequence. It refers to the overlying strata overlapping against an original sedimentary slope in the reverse dip direction. On a seismic section, it is manifested as the in-phase axis above the interface successively terminating on the in-phase axis with a larger dip angle below from a lower position to a higher position.

[0066] (4) Downlap

[0067] The downlap phenomenon often appears at the base of a sequence. It refers to the overlying inclined strata overlapping against an inclined or horizontal original sedimentary surface in the forward dip direction. On a seismic section, it is manifested as the in-phase axis above the interface successively terminating on the in-phase axis with a smaller dip angle below the interface in front of the sediment body. The downlap surface often corresponds to the maximum flooding surface, with a very thin thickness but no sedimentary hiatus;

[0068] According to the seismic reflection termination relationship at the sequence boundary, two third-order sequence boundaries, SB1 and SB2, in the third member of the Zhujiang Formation in the target work area were identified.

[0069] Among them, obvious toplap and onlap termination relationships can be seen in SB1, while the erosion and downlap relationships are not obvious. The in-phase axis generally shows characteristics of low-medium frequency, medium amplitude, and medium continuity.

[0070] Obvious toplap, onlap, and downlap termination relationships can be seen in SB2, while the erosion relationship is not obvious. The in-phase axis generally shows characteristics of low-medium frequency, medium-strong amplitude, and medium continuity ( Figure 2 );

[0071] Step S32: Identify the system tract boundary according to the seismic reflection termination relationship and the accommodation space sequence method;

[0072] Identify the system tract boundary according to the four seismic reflection termination relationships of erosion, toplap, onlap, and downlap and the accommodation space sequence method, including the maximum flooding surface (MFS), the maximum regression surface (MRS), and the forced regression surface (FRS).

[0073] The accommodation space sequence method was proposed by researchers of Exxon in 2009. This method believes that three stratigraphic stacking sequences can be developed successively from bottom to top in a sequence: the PA (progradation - aggradation) sequence, the R (retrogradation) sequence, and the APD (aggradation - progradation - degradation) sequence; among them, the APD sequence can be further divided into the AP (aggradation - progradation) sequence and the PD (progradation - degradation) sequence.

[0074] (1) Maximum flooding surface (MFS): This interface is the boundary between the R (retrogradation) sequence and the AP (aggradation - progradation) sequence in the stratigraphic stacking sequence. Above the interface is the AP (aggradation - progradation) sequence, and below the interface is the R (retrogradation) sequence. On the interface, onlap termination relationship of the in-phase axis and downlap phenomenon of multiple progradational beds can be identified.

[0075] (2) Maximum Regression Surface (MRS): This interface is the boundary between the PA (progradation - aggradation) sequence and the R (retrogradation) sequence in the stratigraphic stacking sequence. Above the interface is the R (retrogradation) sequence, and below the interface is the PA (progradation - aggradation) sequence.

[0076] (3) Forced Regression Surface (FRS): This interface is the boundary between the AP (aggradation - progradation) sequence and the PD (progradation - degradation) sequence in the stratigraphic stacking sequence. Above the interface is the PD (progradation - degradation) sequence, and below the interface is the AP (aggradation - progradation) sequence.

[0077] Step S33: Divide the different system tracts to which the shelf sand ridges belong according to the sequence boundaries and system tract interfaces;

[0078] Based on the identified system tract interfaces, four different system tracts are divided, namely the early transgressive system tract (E - TST), the late transgressive system tract (L - TST), the highstand system tract (HST), and the forced regression system tract (FRST) ( Figure 2 、 Figure 3 ).

[0079] Step S40: Constrained by the seismic horizons of the sand bodies, extract various conventional seismic attributes, and based on well logging data and the Direct software module, extract the single - well sand body thickness; then conduct a correlation analysis between the seismic attributes and the sand body thickness, optimize the seismic attributes, and characterize the sedimentary facies of the banded sand;

[0080] Step S41: Constrained by the seismic horizons of the sand bodies, extract various conventional seismic attributes including amplitude - type, statistical - type, signal - type, and waveform - type;

[0081] Among them, the amplitude - type seismic attributes include root - mean - square amplitude, maximum amplitude, minimum amplitude, half - energy, average positive amplitude, average negative amplitude, average amplitude, and average energy;

[0082] The statistical - type seismic attributes include sum of energy, sum of amplitude, sum of positive amplitude, sum of negative amplitude, threshold value, and amplitude standard deviation;

[0083] The signal - type seismic attributes include average instantaneous amplitude and average instantaneous frequency;

[0084] The waveform - type seismic attributes include arc length;

[0085] Step S42: Based on well logging data, use the Diret software module to extract the single - well sand body thickness of the target layer;

[0086] When counting the sand body thickness, only count the thickness of fine sandstone and siltstone that are favorable for oil and gas accumulation.

[0087] Such as Figure 4As shown, the thickness of the siltstone in the forced regression system domain ranges from 6.8m to 39.3m, with an average thickness of 23.18m. The thickness of the HST siltstone ranges from 2.1m to 13.52m, with an average thickness of 4.76m. The thickness of the L-TST siltstone ranges from 2.1m to 6.2m, with an average thickness of 4.66m. The thickness of the E-TST siltstone ranges from 6.1m to 22.51m, with an average thickness of 14.11m.

[0088] Step S43, performing correlation analysis between the extracted seismic attributes and the sand body thickness, and optimizing the seismic attributes;

[0089] Pearson correlation analysis was used to select seismic attributes with higher correlation with sand thickness.

[0090] The Pearson correlation coefficient calculation formula is as follows:

[0091]

[0092] Where: x is the sand body thickness information; y is the seismic attribute information.

[0093] The strength of the correlation between the seismic attribute information and the lithology information is determined according to the absolute value of the Pearson correlation coefficient:

[0094] When Pearson is between 0.8 and 1.0, there is a very strong correlation;

[0095] When Pearson is between 0.6 and 0.8, there is a strong correlation;

[0096] When Pearson is between 0.4 and 0.6, it is moderately correlated;

[0097] When Pearson is between 0.2 and 0.4, there is a weak correlation;

[0098] When Pearson is between 0.0-0.2, there is very weak correlation or no correlation.

[0099] According to the Pearson correlation coefficient, the root mean square attribute has the best correlation, and the root mean square seismic attribute is preferred to reflect the morphology of the shelf sand ridge in the target work area.

[0100] Step S44, characterizing the sedimentary facies of the shelf sand ridge according to the preferred seismic attributes and in combination with the well logging, core and sand body thickness data;

[0101] (1) Seismic attribute contour: The root mean square attribute can better reflect the planar shape of the shelf sand ridge, and the sand bodies are mostly distributed in the northeast-southwest direction. In the root mean square attribute map, strong amplitude (red color scale) to weak amplitude (green color scale) can also reflect the state of sand body thickness from thick to thin.

[0102] (2) Constraints from well logging, core, and sand thickness data: Using lithologic well logging curves, core identification reports, and the extracted single-well sand body thickness, constrain and adjust the continental shelf sand ridge boundaries characterized based on attributes.

[0103] Step S50: Based on core and thin section data, with the system tract division scheme as a constraint, statistically analyze the lithology of the continental shelf sand ridges according to different system tracts.

[0104] According to the obtained sidewall cores and thin section identification reports, statistically analyze the lithology of the continental shelf sand ridges according to different system tracts. According to the statistical results, the main lithologies are fine sandstone, siltstone, muddy siltstone, and silty mudstone.

[0105] As Figure 7 shown, among them, the main lithologies deposited in FRST are fine sandstone and siltstone, with fine sandstone being the dominant lithology, accounting for 80%, followed by siltstone, accounting for 20%; HST also mainly deposits fine sandstone and siltstone, accounting for 66.67% and 33.33% respectively; L-TST mainly deposits siltstone, muddy siltstone, and silty mudstone, with their proportions being 25%, 20%, and 55% respectively, and the proportion of transitional lithologies reaching 75%; E-TST deposits fine sandstone, siltstone, muddy siltstone, and silty mudstone, with their proportions being 1.61%, 38.71%, 27.42%, and 32.26% respectively. The total proportion of transitional lithologies, muddy siltstone and silty mudstone, is the highest, reaching 59.68%, followed by siltstone, and the least is fine sandstone.

[0106] Step S60: Based on physical property data, with the system tract division scheme as a constraint, statistically analyze the physical property parameters related to the continental shelf sand ridges according to different system tracts.

[0107] The physical property parameters of the continental shelf sand ridges in the target work area are mainly porosity and permeability, which are statistically analyzed according to different system tracts.

[0108] As Figure 8As shown in the figure, the porosity distribution range of FRST is 20.1% - 28.2%, and the average value is 23.72%; the permeability distribution range is 53.7 mD - 606.04 mD, and the average value is 442 mD. The porosity distribution range of HST is 12.3% - 24.5%, and the average value is 19.4%; the permeability distribution range is 11 mD - 675 mD, and the average value is 223.4 mD. The porosity distribution range of L-TST is 8.61% - 15.96%, and the average value is 11.74%; the permeability distribution range is 0.02 mD - 0.7 mD, and the average value is 0.15 mD. The porosity distribution range of E-TST is 3.14% - 17.43%, and the average value is 13.03%; the permeability distribution range is 0.01 mD - 12.04 mD, and the average value is 0.90 mD. According to the physical property data counted, the physical property quality of the shelf sand ridges in different systems can be obtained: FRST > HST > L-TST > E-TST;

[0109] Step S70: Based on the characterized sedimentary microfacies, use CorelDraw software and VB to write a program to count the morphological parameters of the shelf sand ridges in different systems;

[0110] Based on the characterized sedimentary microfacies, use CorelDraw software and VB code to count the morphological parameters of the shelf sand ridges in different systems. The main morphological parameters counted are length, maximum width, area, and trend. Among them, the length and maximum width of the strip sand can be measured using the measurement tool built in CorelDraw software; the closed graphic area calculation code written in VB language can also be used to measure the area of the shelf sand ridges when running in CorelDraw software.

[0111] It should be noted that the VB code for measuring the area is publicly released on the Internet, and its code is:

[0112] Sub Test()

[0113] On Error Resume Next

[0114] ActiveDocument.Unit = cdrMillimeter

[0115] Dim sl As Shape, xSel As ShapeRange, m As Double, n As Double

[0116] Set xSel = ActiveSelectionRange

[0117] If ActiveSelectionRange.Count>1 Or ActiveSelectionRange.Count = 0 Then

[0118] MsgBox "Please select 1 curve first."

[0119] Exit Sub

[0120] End If

[0121] m = xSel.Shapes(1).Curve.Length

[0122] n = xSel.Shapes(1).Curve.Area

[0123] MsgBox "Curve length L (mm): " & Format(m, "0.0000") & Chr(13) & "Curve area S (mm2): " & Format(n, "0.0000")

[0124] End Sub

[0125] Step S80: Comprehensively analyze the statistically obtained morphological parameters of the shelf sand ridges, and classify the shelf sand ridge morphology according to different systems tracts;

[0126] The shelf sand ridge morphology is divided into Type I, Type II, and Type III; among them, Type I is wide in the south and narrow in the north; Type II is approximately equal in width from north to south; Type III is slightly wider in the north and narrower in the south.

[0127] In the forced regression systems tract, the morphology of the shelf sand ridges is mostly Type I (wide in the south and narrow in the north); in the early stage of the transgressive systems tract, it is mainly Type II (approximately equal in width from north to south), with some Type III (slightly wider in the north and narrower in the south); in the late stage of the transgressive systems tract, it is mainly Type III (slightly wider in the north and narrower in the south), with some Type II (approximately equal in width from north to south).

[0128] Step S90: Calculate the hydrodynamic index of different systems tracts according to the morphological characteristics of the shelf sand ridges;

[0129] During the deposition period of the shelf sand ridges in the target work area, it was affected by the north - east to south - west tides and the south - west coastal current for a long time. Due to the characteristics of the two - way flow of the tides, the planar shape of the sand body is easily transformed into a relatively symmetric shape, that is, Type II or Type III sand bodies; while the coastal current tends to be unidirectional transformation and is prone to form Type I sand bodies with convergence in the north and divergence in the south. In order to highlight the morphological differences caused by different hydrodynamic influences, the hydrodynamic index (Δ) is defined for semi - quantitative characterization, and its expression is:

[0130]

[0131] Where: L1 is the maximum width value of the northern part of the strip sand body; L2 is the maximum width value of the southern part of the strip sand body; Δ is the hydrodynamic index;

[0132] Among them, for the hydrodynamic index Δ, when the value is approximately close to 0, it indicates that the sand body is mainly affected by tidal action; on the contrary, when the value deviates more from 0, it indicates that the sand body is mainly affected by the longshore current;

[0133] During measurement, all the shelf sand ridges are approximately regarded as symmetric strip objects, and the symmetry axis of the sand body is roughly found, and the maximum values are measured along the symmetry axis towards the south and north respectively.

[0134] The statistical results show that during the FRST period, the number of type I sand bodies is the largest, with its hydrodynamic index ranging from 0.47 to 1.08 and an average value of 0.70; the hydrodynamic index of type II sand bodies ranges from 0.11 to 0.31 and an average value of 0.19; the hydrodynamic index of type III sand bodies ranges from 0.47 to 0.60 and an average value of 0.53. During the HST period, the number of type II sand bodies is the largest, with its hydrodynamic index ranging from 0.01 to 0.50 and an average value of 0.18; the hydrodynamic index of type I sand bodies ranges from 0.55 to 0.68 and an average value of 0.62; the hydrodynamic index of type III sand bodies ranges from 0.14 to 0.55 and an average value of 0.32. During the L-TST period, the number of type III sand bodies is the largest, with its hydrodynamic index ranging from 0.10 to 0.71 and an average value of 0.25; the hydrodynamic index of type I sand bodies ranges from 0.44 to 0.96 and an average value of 0.65; the hydrodynamic index of type II sand bodies ranges from 0.02 to 0.09 and an average value of 0.06. During the E-TST period, the number of type II sand bodies is the largest, with its hydrodynamic index ranging from 0.01 to 0.55 and an average value of 0.20; the hydrodynamic index of type I sand bodies ranges from 0.64 to 1.37 and an average value of 1.06( Figure 9 ).

[0135] Generally speaking, the hydrodynamic index of type I sand bodies mainly modified by waves is greater than that of type II and type III sand bodies mainly modified by tides. The average hydrodynamic index of type I sand bodies is 0.73, and the average hydrodynamic indices of type II and type III sand bodies are 0.16 and 0.30 respectively;

[0136] Step S100: Determine the hydrodynamic influence types of different system tracts according to the morphological types of the shelf sand ridges and the hydrodynamic indices of different system tracts;

[0137] When the shape of the shelf sand ridge is type I and the hydrodynamic index Δ is 0.62 - 1.06, its hydrodynamic influence type is mainly wave action;

[0138] When the shape of the shelf sand ridge is type II and the hydrodynamic index Δ is 0.06 - 0.2, its hydrodynamic influence type is mainly tidal action;

[0139] When the shelf sand ridge is of type Ⅲ, the hydrodynamic index Δ is 0.25 - 0.53, and its hydrodynamic influence type is alongshore current - tidal hybrid power.

[0140] Characterize the shelf sand ridge features of different systems tracts by integrating lithology, physical properties, morphology parameters, morphology types, quantitative relationships and hydrodynamic indices:

[0141] (1) Forced regression systems tract (FRST)

[0142] The strip sandstone lithology is mainly fine sandstone and siltstone; the porosity ranges from 20.1% to 28.2%, with an average of 23.72%; the permeability ranges from 53.7 mD to 606.04 mD, with an average of 442 mD; the length ranges from 4.36 to 21.16 km, with an average of 13.92 km; the maximum width ranges from 1.56 to 6.07 km, with an average of 3.43 km; the area ranges from 9.82 to 59.15 km 2 , with an average of 33.45 km 2 ; the strike is mainly NE - SW; the morphology is mainly of type Ⅰ (narrow in the north and wide in the south); the hydrodynamic type is mainly alongshore current, and the hydrodynamic index ranges from 0.47 to 1.08, with an average of 0.70.

[0143] (2) Highstand systems tract (HST)

[0144] The strip sandstone lithology is mainly fine sandstone and siltstone; the porosity ranges from 12.3% to 24.5%, with an average of 19.4%; the permeability ranges from 11 mD to 675 mD, with an average of 223.4 mD; the length ranges from 2.54 to 20.1 km, with an average of 6.52 km; the maximum width ranges from 0.88 to 3.19 km, with an average of 1.70 km; the area ranges from 1.91 to 52.35 km 2 , with an average of 14.56 km 2 ; the strike is mainly NE - SW; the morphology is mainly of type Ⅱ (narrow in the north and wide in the south); the hydrodynamic type is mainly tidal, and its hydrodynamic index ranges from 0.01 to 0.50, with an average of 0.18.

[0145] (3) Late transgressive systems tract (L - TST)

[0146] The strip sandstone lithology is mainly transitional rock, followed by siltstone; the porosity ranges from 8.61% to 15.96%, with an average of 11.74%; the permeability ranges from 0.02 mD to 0.7 mD, with an average of 0.15 mD; the length ranges from 2.84 to 13.32 km, with an average of 8.79 km; the maximum width ranges from 0.86 to 4.57 km, with an average of 1.9 km; the area ranges from 2.78 to 26.83 km 2, with an average value of 12.96 km 2 ; The morphology is mainly of type III (slightly wider in the north - narrower in the south); The hydrodynamic type is mainly tidal, and its hydrodynamic index ranges from 0.10 to 0.71, with an average value of 0.25.

[0147] (4) Early transgressive systems tract (E - TST)

[0148] The strip sandstone is mainly siltstone, and the content of transitional rock is high; The porosity ranges from 3.14% to 17.43%, with an average value of 13.03%; The permeability ranges from 0.01 mD to 12.04 mD, with an average value of 0.90 mD; The length ranges from 2.54 to 19.89 km, with an average value of 9.48 km; The maximum width ranges from 0.76 to 3.73 km, with an average value of 2.04 km; The area ranges from 3.63 to 31.31 km 2 , with an average value of 14.56 km 2 ; The strike is mainly northeast - southwest; The morphology is mainly of type II (similar width in the north and south); The hydrodynamic type is mainly tidal, and its hydrodynamic index ranges from 0.01 to 0.55, with an average value of 0.20.

[0149] As mentioned above, it is not a restriction on the present invention in any form. Although the present invention has been disclosed through the above - mentioned embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above - disclosed technical content to form equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above - mentioned embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges, characterized in that, It includes the following steps: Step S10: Obtain relevant data for characterizing the features of the shelf sand ridges in the target work area; Step S20: Based on the seismic data of the target work area and taking the shelf sand ridge horizon interpretation plan as the basis, carry out seismic horizon interpretation of the sand bodies; Step S30: According to the seismic reflection termination relationship and the accommodation space sequence method, identify the sequence boundaries and system tract interfaces, and based on the identified interfaces, divide the target layer shelf sand ridges into different system tracts respectively; Step S40: Constrained by the seismic horizons of the sand bodies, extract various conventional seismic attributes, and based on well logging data and the Direct software module, extract the single-well sand body thickness; then conduct a correlation analysis between the seismic attributes and the sand body thickness, optimize the seismic attributes, and characterize the sedimentary facies of the banded sand; Step S50: Based on the core and thin section data, constrained by the system tract division plan, count the lithology of the shelf sand ridges according to different system tracts; Step S60: Based on the physical property data and constrained by the system tract division plan, count the relevant physical property parameters of the shelf sand ridges according to different system tracts; Step S70: Based on the characterized sedimentary microfacies, use CorelDraw software and VB to write a program to count the morphological parameters of the shelf sand ridges in different system tracts; Step S80: Comprehensively analyze the counted morphological parameters of the shelf sand ridges, and classify the morphology of the shelf sand ridges according to different system tracts; Step S90: Calculate the hydrodynamic index of different system tracts according to the morphological characteristics of the shelf sand ridges; Step S100: Determine the hydrodynamic influence types of different system tracts according to the morphological types of the shelf sand ridges and the hydrodynamic indices of different system tracts.

2. The hydrodynamic quantitative evaluation method based on the morphology of continental shelf sand ridges according to claim 1, wherein, The relevant data includes seismic data, well logging data, core / thin section data, physical property data, and regional geological data.

3. The hydrodynamic quantitative evaluation method based on the morphology of continental shelf sand ridges according to claim 1, wherein When conducting seismic horizon interpretation of the sand bodies in Step S20, follow the principles of isochronous correlation, hierarchical control, and pattern guidance, adopt the well-seismic combination method, and interact between the plane and the profile to achieve closed interpretation of the sand body horizons.

4. The hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges according to claim 1, wherein The specific process of Step S30 includes: Step S31: Identify the sequence boundaries according to the seismic reflection termination relationship and sequence stratigraphy theories and methods; Step S32: Identify the system tract interfaces according to the seismic reflection termination relationship and the accommodation space sequence method; Step S33: Divide the different system tracts to which the shelf sand ridges belong according to the sequence boundaries and system tract interfaces.

5. The hydrodynamic quantitative evaluation method based on the morphology of continental shelf sand ridges according to claim 1, wherein The specific process of Step S40 includes: Step S41: Constrained by the seismic horizons of the sand bodies, extract various conventional seismic attributes including amplitude type, statistical type, signal type, and waveform type; Step S42: Based on the well logging data, use the Diret software module to extract the single-well sand body thickness of the target layer; Step S43: Conduct a correlation analysis between the extracted seismic attributes and the sand body thickness, and optimize the seismic attributes; Step S44: According to the optimized seismic attributes, and combined with well logging, core, and sand body thickness data, characterize the sedimentary facies of the shelf sand ridges.

6. The hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges according to claim 1, characterized in that The relevant physical property parameters of the shelf sand ridges in Step S60 include porosity and permeability.

7. The hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges according to claim 1, characterized in that The morphological parameters of the shelf sand ridges in Step S70 include length, maximum width, area, and strike.

8. A hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges according to claim 1, characterized in that In step S80, the morphology of the shelf sand ridge is divided into type I, type II, and type III. Among them, type I is wider in the south and narrower in the north; type II has approximately equal widths in the north and south; type III is slightly wider in the north and narrower in the south.

9. The hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges according to claim 1, characterized in that In step S90, the calculation formula for the hydrodynamic index is as follows: In the formula: L1 is the maximum width value of the northern part of the strip sand body; L2 is the maximum width value of the southern part of the strip sand body; Δ is the hydrodynamic index.

10. The hydrodynamic quantitative evaluation method based on the morphology of shelf sand ridges according to claim 1, characterized in that, In step S100, when the shelf sand ridge is of type I, the hydrodynamic index Δ is 0.62 - 1.06, and its hydrodynamic influence type is mainly wave action; when the shelf sand ridge is of type II, the hydrodynamic index Δ is 0.06 - 0.2, and its hydrodynamic influence type is mainly tidal action; when the shelf sand ridge is of type III, the hydrodynamic index Δ is 0.25 - 0.53, and its hydrodynamic influence type is alongshore current - tidal hybrid power.

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