Small-layer subdivision modeling method based on seismic information guidance

Abstract

The invention provides a small layer subdivision modeling method based on seismic information guidance, and the method comprises the steps: 1, selecting a seed point (il, xl) in an earthquake uninterpreted horizon region; step 2, tracking the horizon of the il line according to the inclination angle volume data along the INLINE direction of the seed point; step 3, calculating the horizon positions of all channels of a next INLINE line i'line along the direction of the XLINE line; step 4, selecting a seed point (il ', xl') in the horizon line, and tracking the horizon of the il'line along the INLINE direction; 5, tracking of all layers is completed; and step 6, completing all tracking of all horizon points. According to the small-layer subdivision modeling method based on seismic information guidance, the influence of seismic noise, faults and seismic amplitude changes can be avoided, an accurate and stable seismic dip angle data body is obtained, and the seismic dip angle is extracted accurately.

Description

Technical Field

[0001] The invention relates to the technical field of oil reservoir geophysics, and in particular to a small layer subdivision modeling method based on seismic information guidance. Background Art

[0002] In conventional geological modeling, large-layer modeling of strata is often carried out based on the seismic horizon constraints of seismic data. However, compared with reservoir development, such modeling often results in strata that are too thick and not accurate enough to meet the needs of reservoir development. Therefore, it is necessary to subdivide the established large-layer model. Common subdivision methods are equal division, equal-thickness subdivision along the top layer, waiting subdivision along the bottom layer, or subdividing the layer at a certain ratio. Such subdivision methods often result in the problem that the subdivided model layer will pass through the isochronous strata. Therefore, a new large-layer segmentation method is needed, which can subdivide large layers without the problem of model layers passing through the isochronous grid of the strata, so as to accurately describe the reservoir strata.

[0003] In the Chinese patent application with application number: CN201510705539.1, a method and device for tracking seismic layers are involved. In one embodiment, the method includes: obtaining the first waveform characteristic information of the initial seed point on the target layer; setting the search range of the initial seed point on the adjacent seismic trace; obtaining the second waveform characteristic information of the initial seed point within the search range; based on the first waveform characteristic information and the second waveform characteristic information, calculating the third characteristic matrix corresponding to the initial seed point; determining the position of similar seed points according to the third characteristic matrix, and tracking the seismic layers with the similar seed points. This application implementation method can realize the tracking of seismic layers more accurately and quickly.

[0004] In the Chinese patent application with application number: CN201910280939.0, a method and device for full-layer tracking of earthquakes is involved, which includes: obtaining three-dimensional seismic data; extracting layer extreme points from the three-dimensional seismic data to construct a sample space; dividing the sample space into multiple subspaces with overlapping parts, clustering the layer extreme points in each subspace, and obtaining layer fragments corresponding to each layer of the three-dimensional seismic data; establishing topological consistency between the layer fragments; based on the topological consistency, fusing the layer fragments corresponding to each layer of the three-dimensional seismic data to obtain the full-layer tracking result of the three-dimensional seismic data. This invention removes the influence of local connectivity between some different layers in the three-dimensional seismic data, avoids the layer stringing phenomenon generated during full-layer tracking, and fuses the generated layer fragments by establishing topological consistency, thereby improving the accuracy of layer fragment fusion and having a better full-layer tracking effect.

[0005] In the Chinese patent application with application number: CN202011398831.0, a method for modeling oilfield sand body geology is involved, which includes: A. Layer division based on well-seismic combination: subdividing the oil group at the well point, extracting seismic attributes based on the oil group marker layer on the seismic inversion data body, determining the layer interface according to the change of seismic attributes, and then comparing the interface of the well point layer with the layer interface determined on the seismic inversion data body, and fitting the two to obtain the final modeling layer interface; B. Establishment of a structural framework model: using the modeling layer interface obtained by layer division, a structural framework model controlled by the layer interface is established; C. Using a simulation algorithm to establish a lithofacies model: determine the direction and size of the sandstone lithofacies or mudstone lithofacies change range, and use the seismic inversion data body attributes of each layer as constraints to establish a three-dimensional lithofacies model; D. Using the lithofacies model as a control, establish a porosity and permeability model inside the sandstone lithofacies. This invention can model the sand body geology of offshore oil fields more accurately and quickly.

[0006] In the Chinese patent application with application number: CN201910322660.4, a shale gas reservoir structure modeling method and device are involved, which includes: obtaining logging information of multiple vertical wells within a preset range of the shale gas work area, and stratifying multiple horizontal wells in the shale gas work area according to the logging information; obtaining the average total thickness of the target layer and the average thickness of each small layer of multiple vertical wells within the preset range of the shale gas work area according to the logging information; calculating the top depth value and the bottom depth value of the target layer by using the stratification information of each small layer after stratification of the horizontal well and the average thickness of each small layer of the target layer of the vertical well, and establishing the top and bottom structural surfaces of the target layer in combination with the structural surface of the target layer obtained by seismic data interpretation; under the constraints of the top and bottom structural surfaces of the target layer, splitting the target layer in combination with the average total thickness of the target layer and the average thickness of each small layer, establishing the structural plane of each small layer, and establishing the structural model of the shale gas reservoir by using the structural plane of each small layer. The invention can ensure the accuracy of the reservoir structure model.

[0007] The above existing technologies are all significantly different from the present invention and fail to solve the technical problem we want to solve. For this reason, we have invented a new small layer subdivision modeling method based on seismic information guidance. Summary of the invention

[0008] The object of the present invention is to provide a small layer subdivision modeling method based on seismic information guidance, which can avoid the problem of subdivision model layers crossing the isochronous grid of the strata, thereby accurately describing the reservoir strata.

[0009] The object of the present invention can be achieved by the following technical measures: a small layer subdivision modeling method based on seismic information guidance, the small layer subdivision modeling method based on seismic information guidance comprises:

[0010] Step 1, select the seed point (il, xl) in the uninterpreted seismic horizon area;

[0011] Step 2, tracing the layer of the il line according to the dip volume data along the INLINE direction of the seed point;

[0012] Step 3, calculate the horizons of all traces of the next INLINE line il' along the XLINE line direction;

[0013] Step 4, select a seed point (il', xl') in the horizon line, and trace the horizon of the il' line along the INLINE direction;

[0014] Step 5, complete the tracking of all layers;

[0015] Step 6: Complete the tracking of all layer sites.

[0016] The purpose of the present invention can also be achieved by the following technical measures:

[0017] In step 1, on the calculated dip volume, in the middle of the seismic interpretation horizon, a point in an enlarged area without faults is selected as a seed point.

[0018] In step 1, the dip body refers to the formation dip data body calculated based on the actual observed post-stack seismic records or the synthetic records established based on the geological model.

[0019] In step 2, INLINE refers to the line data direction of the seismic data.

[0020] In step 2, starting from the seed point (il,xl,t), according to the formation inclination, calculate the layer value tl of the next point (il,xl+1) or (il,xl-1) along the INLINE direction to obtain (il,xl+1,tl) or (il,xl-1,tl); repeat this step until all traces of the il line are calculated.

[0021] In step 3, on the INLINE tracked layer, according to the dip volume data, the layer of the next INLINE line il' is tracked along the XLINE direction, and then the layer of all channels of the il' line is calculated along the INLINE line direction. The calculated layer value is weighted constrained with the original layer value to ensure that the layer does not deviate too far; the survey line il' is the survey line il+1 or the survey line il-1.

[0022] In step 3, INLINE refers to the survey line data direction of the seismic data; XLINE refers to the cross survey line data direction of the seismic data; and survey line il' refers to survey line il+1 or survey line il-1.

[0023] In step 4, for the point (il,xl) on INLINE, the layer time value tx at (il,xl) is calculated by the layer position and dip angle at (il-1,xl) or (il-1,xl); then the layer time value tl at (il,xl) is calculated by the layer position and dip angle at (il,xl+1) or (il,xl-1), and finally the average value of tl and tx is taken as the value of the point, that is, t=(tx+tl)*0.5.

[0024] In step 4, a layer with a value is selected in the middle of the layer line in step 3 as the seed point (il', xl'), and the layer of the il' line is traced according to the dip volume data along the INLINE direction and the XLINE direction. The calculated layer value is weighted averaged with the original layer value.

[0025] In step 5, repeat steps 3 and 4 until all layers are tracked.

[0026] In step 6, a seed point is selected at the location where the layer position has not been calculated, and steps 2 to 6 are repeated until all layer points are tracked.

[0027] The small layer subdivision modeling method based on seismic information guidance in the present invention meets the requirements of accurately describing the stratigraphic isochronous grid of reservoir modeling, and mainly provides a method for accurately extracting seismic dip angle, which is mainly used to analyze the stratigraphic dip angle of geological strata and understand the inclination of strata. The method mainly calculates the eigenvector value of the Hessian matrix by improving the Hessian matrix construction method, thereby obtaining the stratigraphic dip angle body data of the strata. The method can avoid the influence of seismic noise, faults and seismic amplitude changes, obtain accurate and stable seismic dip angle data body, and extract the accuracy of seismic dip angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a formation dip angle data volume calculated from seismic records in a specific embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of calculating the stratigraphic level according to the guidance of the stratigraphic dip body in a specific embodiment of the present invention;

[0030] Figure 3 The present invention is a flowchart of a specific embodiment of the method for small layer subdivision modeling based on seismic information guidance. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0033] In order to meet the requirement of accurately describing the stratigraphic isochronous framework in reservoir modeling, the present invention provides a method for subdividing small layers based on seismic dip guidance, which can avoid the problem of subdividing model layers crossing the stratigraphic isochronous framework, thereby accurately describing the reservoir strata.

[0034] like Figure 3 As shown in the figure, it is a flow chart of the small layer subdivision modeling method based on seismic information guidance of the present invention. The small layer subdivision modeling method based on seismic information guidance includes:

[0035] 101) On the calculated dip body, in the uninterpreted seismic horizon area, select a point in an enlarged area without faults as a seed point;

[0036] 102) trace the horizon of the line according to the dip volume data along the INLINE direction of the point;

[0037] 103) On the INLINE traced layer, trace the layer of the next INLINE line along the XLINE direction according to the dip volume data;

[0038] 104) Select a layer with a value in the middle of the layer line of 103) as a seed point, and trace the layer of this line according to the dip volume data along the INLINE direction, and perform a weighted average of the calculated layer value and the original layer value;

[0039] 105) repeating steps 103) and 104) until all layers are tracked;

[0040] 106) Select a seed point at the location where the layer position has not been calculated, and repeat 102), 103), 104), 105), and 106) until all layer positions are tracked.

[0041] The following are several specific embodiments of the present invention.

[0042] Example 1

[0043] In a specific embodiment 1 of the present invention, the small layer subdivision modeling method based on seismic information guidance includes the following steps:

[0044] 1) On the calculated dip body, in the area where there is no seismic interpretation, select a point in the enlarged area without faults as the seed point (il, xl, t);

[0045] The dip body refers to the formation dip data body calculated based on the actual observed post-stack seismic records or the synthetic records established based on the geological model, such as Figure 1 As shown;

[0046] 2) Trace the horizon of the line according to the dip volume data along the INLINE direction of the point;

[0047] INLINE refers to the survey line data direction of seismic data;

[0048] Starting from the seed point (il,xl,t), according to the formation dip, calculate the layer value tl of the next point (il,xl+1) or (il,xl-1) along the INLINE direction to obtain (il,xl+1,tl) or (il,xl-1,tl); repeat this step until all channels of the line are calculated; the specific algorithm is as follows:

[0049] The horizon time at (il,xl+1) is tl=t+D*L*K

[0050] The horizon time at (il,xl-1) is tl=tD*L*K

[0051] Among them, t is the horizon time at (il,xl), D is the dip angle of the formation in the INLINE direction of (il,xl), L is the interval between seismic traces, and K is the formation dip coefficient.

[0052] 3) On the INLINE traced layer, trace the layer of the next INLINE line along the XLINE direction according to the dip volume data;

[0053] INLINE refers to the survey line data direction of seismic data; XLINE refers to the cross survey line data direction of seismic data; the next INLINE line refers to the INLINE line (il+1) or the INLINE line (il-1);

[0054] For each point on INLINEil, such as (il,xl), calculate the layer time value tx at (il+1,xl); the specific algorithm is as follows:

[0055] The horizon time at (il+1,xl) is tx=t+D*L*K

[0056] Among them, t is the horizon time at (il, xl), D is the dip angle of the formation XLINE direction at (il, xl), L is the interval between seismic lines, and K is the formation dip coefficient.

[0057] 4) Select a layer with a value in the middle of the layer line of 3) as the seed point, and trace the layer of this line according to the dip volume data along the INLINE direction, and perform weighted average of the calculated layer value and the layer value calculated in 3);

[0058] For example, select a point as a seed point such as (il+1, xl), and calculate the layer time value tl at (il+1, xl+1) or (il+1, xl-1) along the INLINE direction; the specific algorithm is as follows:

[0059] The horizon time at (il+1,xl+1) is tl=t+D*L*K

[0060] The horizon time at (il+1,xl-1) is tl=tD*L*K

[0061] Among them, t is the horizon time at (il+1,xl), D is the inclination of the formation in the INLINE direction of (il+1,xl), L is the interval between seismic traces, and K is the formation inclination coefficient.

[0062] Finally, the average value of tl and tx is taken as the value of this point, that is, t = (tx + tl) * 0.5;

[0063] tx refers to the horizon time calculated in 3);

[0064] 5) Repeat steps 3) and 4) until all layers are tracked;

[0065] 6) Select seed points at the locations where the layers have not been calculated, and repeat 2), 3), 4), 5), and 6) until all the points in all layers are tracked. The results are as follows: Figure 2 shown.

[0066] exist Figure 2 In the figure, the base map is the seismic post-stack data map; the black lines are the equal stratification lines of the top and bottom of the strata; and the gray lines are the strata of the small layer decomposition guided by the seismic dip angle.

[0067] Example 2

[0068] In a specific embodiment 1 of the present invention, the small layer subdivision modeling method based on seismic information guidance includes the following steps:

[0069] 1) On the calculated dip body, in the area where there is no seismic interpretation, select a point in the enlarged area without faults as the seed point (il, xl, t);

[0070] The dip body refers to the formation dip data body calculated based on the actual observed post-stack seismic records or the synthetic records established based on the geological model, such as Figure 1 As shown;

[0071] 2) Trace the horizon of the line according to the dip volume data along the INLINE direction of the point;

[0072] INLINE refers to the survey line data direction of seismic data;

[0073] Starting from the seed point (il,xl,t), according to the formation dip, calculate the layer value tl of the next point (il,xl-1) along the INLINE direction to obtain (il,xl-1,tl); repeat this step until all channels of the line are calculated; the specific algorithm is as follows:

[0074] The horizon time at (il,xl-1) is tl=tD*L*K

[0075] Among them, t is the horizon time at (il,xl), D is the dip angle of the formation in the INLINE direction of (il,xl), L is the interval between seismic traces, and K is the formation dip coefficient.

[0076] 3) On the INLINE traced layer, trace the layer of the next INLINE line along the XLINE direction according to the dip volume data;

[0077] INLINE refers to the survey line data direction of seismic data; XLINE refers to the cross survey line data direction of seismic data; the next INLINE line refers to the INLINE line (il+1) or the INLINE line (il-1);

[0078] For each point on INLINEil, such as (il,xl), calculate the layer time value tx at (il-1,xl); the specific algorithm is as follows:

[0079] The horizon time at (il-1,xl) is tx=tD*L*K

[0080] Among them, t is the horizon time at (il, xl), D is the dip angle of the formation XLINE direction at (il, xl), L is the interval between seismic lines, and K is the formation dip coefficient.

[0081] 4) Select a layer with a value in the middle of the layer line of 3) as the seed point, and trace the layer of this line according to the dip volume data along the INLINE direction, and perform weighted average of the calculated layer value and the layer value calculated in 3);

[0082] For example, select a point as a seed point such as (il-1, xl), and calculate the layer time value tl at (il-1, xl+1) or (il-1, xl-1) along the INLINE direction; the specific algorithm is as follows:

[0083] The horizon time at (il-1,xl+1) is tl=t+D*L*K

[0084] The horizon time at (il-1, xl-1) is tl=tD*L*K

[0085] Among them, t is the horizon time at (il-1,xl), D is the inclination of the formation in the INLINE direction of (il-1,xl), L is the interval between seismic traces, and K is the formation inclination coefficient.

[0086] Finally, the average value of tl and tx is taken as the value of this point, that is, t = (tx + tl) * 0.5;

[0087] tx refers to the horizon time calculated in 3);

[0088] 5) Repeat steps 3) and 4) until all layers are tracked;

[0089] 6) Select seed points at uncalculated layers, and repeat 2), 3), 4), 5), and 6) until all layer points are tracked.

[0090] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0091] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A small layer subdivision modeling method based on seismic information guidance, characterized in that: The small layer subdivision modeling method based on seismic information guidance includes: Step 1, select the seed point (il, xl) in the uninterpreted seismic horizon area; Step 2, tracing the layer of the il line according to the dip volume data along the INLINE direction of the seed point; Step 3, calculate the horizons of all traces of the next INLINE line i l' along the XLINE line direction; Step 4, select a seed point (il', xl') in the horizon line, and trace the horizon of the il' line along the INLINE direction; Step 5, complete the tracking of all layers; Step 6: Complete the tracking of all layer sites.

2. The small layer subdivision modeling method based on seismic information guidance according to claim 1 is characterized in that: In step 1, on the calculated dip volume, in the middle of the seismic interpretation horizon, a point in an enlarged area without faults is selected as a seed point.

3. The small layer subdivision modeling method based on seismic information guidance according to claim 2 is characterized in that: In step 1, the dip body refers to the formation dip data body calculated based on the actual observed post-stack seismic records or the synthetic records established based on the geological model.

4. The small layer subdivision modeling method based on seismic information guidance according to claim 1 is characterized in that: In step 2, INLINE refers to the line data direction of the seismic data.

5. The small layer subdivision modeling method based on seismic information guidance according to claim 4 is characterized in that: In step 2, starting from the seed point (il,xl,t), according to the formation inclination, calculate the layer value tl of the next point (il,xl+1) or (il,xl-1) along the INLINE direction to obtain (il,xl+1,tl) or (il,xl-1,tl); repeat this step until all traces of the il line are calculated.

6. The small layer subdivision modeling method based on seismic information guidance according to claim 1 is characterized in that: In step 3, on the INLINE tracked layer, according to the dip volume data, the layer of the next INLINE line il' is tracked along the XLINE direction, and then the layer of all channels of the il' line is calculated along the INLINE line direction. The calculated layer value is weighted constrained with the original layer value to ensure that the layer does not deviate too far; the survey line il' is the survey line il+1 or the survey line il-1.

7. The small layer subdivision modeling method based on seismic information guidance according to claim 6 is characterized in that: In step 3, INLINE refers to the survey line data direction of the seismic data; XLINE refers to the cross survey line data direction of the seismic data; and survey line il' refers to survey line il+1 or survey line il-1.

8. The small layer subdivision modeling method based on seismic information guidance according to claim 7 is characterized in that: In step 4, for the point (il,xl) on INLINE, the layer time value tx at (il,xl) is calculated by the layer position and dip angle at (il-1,xl) or (il-1,xl); then the layer time value tl at (il,xl) is calculated by the layer position and dip angle at (il,xl+1) or (il,xl-1), and finally the average value of tl and tx is taken as the value of the point, that is, t=(tx+tl)*0.

5.

9. The small layer subdivision modeling method based on seismic information guidance according to claim 8 is characterized in that: In step 4, a layer with a value is selected in the middle of the layer line in step 3 as the seed point (il', xl'), and the layer of the il' line is traced according to the dip volume data along the INLINE direction and the XLINE direction. The calculated layer value is weighted averaged with the original layer value.

10. The small layer subdivision modeling method based on seismic information guidance according to claim 1 is characterized in that: In step 5, repeat steps 3 and 4 until all layers are tracked.

11. The small layer subdivision modeling method based on seismic information guidance according to claim 1 is characterized in that: In step 6, a seed point is selected at the location where the layer position has not been calculated, and steps 2 to 6 are repeated until all layer points are tracked.

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