Reservoir prediction method based on deposition difference

Abstract

The invention provides a reservoir prediction method based on deposition difference, and the method comprises the steps: 1, comparing and analyzing the drilling conditions of single wells, obtaining the thicknesses of reservoirs between the wells, and dividing the types of the reservoirs; 2, performing matching analysis on the deposition difference of different layer development and the reservoir type in the step 1; 3, restoring the positions of the river channels in different deposition periods according to a matching result; and step 4, reservoir prediction is carried out by using a seismic attribute extraction method and combining the river channel position. The reservoir prediction result provided by the reservoir prediction method based on the deposition difference has a good application effect, well location deployment and implementation effects are improved by using the technology, and the actual reservoir drilling encounter distribution and prediction coincidence rate is high.

Description

Technical Field

[0001] The invention relates to the field of oil and gas development geology and geophysical technology, and in particular to a reservoir prediction method based on sedimentation differences. Background Art

[0002] Reservoir prediction is an important basis for oil and gas field development. With the deepening of development, the distribution of remaining oil becomes more scattered, and the accuracy of reservoir prediction using seismic data is increasingly required. For development areas with low well control and narrow river channel deposits, the sand body changes rapidly laterally, the well connectivity is poor, and the heterogeneity is strong. The accuracy of reservoir prediction directly affects the development effect of oil and gas fields.

[0003] At present, the inversion and attribute extraction methods are mostly used for reservoir prediction using seismic data. The inversion data contains impedance information to reflect the rock characteristic parameters. Due to the strong heterogeneity of river phase narrow channel sedimentary reservoirs, the inversion accuracy is difficult to guarantee. Attribute extraction is based on the difference in reservoir characteristics, extracting information such as amplitude, waveform, and phase. This method has high requirements for drilling information and has multiple solutions for areas with low or no well control, resulting in low reservoir prediction accuracy and bringing difficulties to the subsequent fine description of reservoirs.

[0004] In the Chinese patent application with application number: CN201710289032.1, a reservoir prediction method under the guidance of a phase-controlled rock physics model is involved, including: dividing sedimentary phases; obtaining the differences in the main mineral components of the reservoir in each sedimentary phase; preliminarily determining the rock physics modeling parameters in each sedimentary phase; establishing a preliminary rock physics model of the reservoir in each sedimentary phase; obtaining the difference between the simulated data and the measured data, and if the difference exceeds the preset error allowable value, adjusting the modeling parameters and re-establishing the rock physics model until the final rock physics model in each sedimentary phase is obtained; determining the two elastic parameters that are most sensitive to the changes in characteristic minerals; calculating the relationship curve of the two elastic parameters; obtaining the distribution of the two elastic parameters in the entire three-dimensional seismic area; dividing the distribution of the two elastic parameters in the entire three-dimensional seismic area into reservoirs and non-reservoirs, and obtaining the reservoir distribution in the entire three-dimensional seismic area. This invention can improve the accuracy of reservoir prediction under complex geological conditions.

[0005] In the Chinese patent application with application number: CN201710289031.7, a method for performing reservoir AVO analysis under the control of sedimentary phases is involved, including: using the logging data and seismic attribute data of the area to divide the sedimentary phases; according to the identification results of the drilling core and thin section, combined with the analysis results of the sedimentary process, the differences in the main mineral components of the reservoir in each sedimentary phase are obtained; the qualitative differences in the rock physical properties of the reservoir in each sedimentary phase are obtained; the differences in the AVO characteristics of the reservoir in different sedimentary phases are obtained by using the differences in the rock physical properties of the reservoir in different sedimentary phases, and the differences in the AVO characteristics are verified by using the AVO forward modeling of the reservoir on the well and the AVO analysis of the actual seismic traces near the well; according to the differences in the AVO characteristics of the reservoir in different sedimentary phases after verification, the reservoir AVO analysis is performed separately within each sedimentary phase to obtain the vertical and horizontal distribution of the reservoir in each sedimentary phase. The invention divides the distribution boundaries of each AVO feature, performs reservoir prediction within each boundary, reduces the prediction multi-solution, and improves the exploration success rate.

[0006] In the Chinese patent application with application number: CN201310597627.5, a method for predicting the production capacity of a dense clastic natural gas well based on reservoir classification is involved. The method includes: obtaining the effective thickness of the reservoir and the effective thickness of the thin interlayer according to the well logging data; calculating the mud content of the reservoir according to the natural gamma and three-porosity curves; calculating the reservoir porosity according to the acoustic wave, neutron and density curves, and classifying the reservoir; calculating the reservoir permeability and gas saturation according to the core analysis porosity and Archie formula; using thickness weighting to perform reservoir classification calculations, and summing to obtain a comprehensive gas index; introducing the concept of thin interlayers according to the differences in reservoir sedimentary microfacies, and obtaining an improved comprehensive gas index; establishing the relationship between the improved comprehensive gas index and the test production capacity, and using this as a model to predict the production capacity of other reservoirs. The invented method has a high reservoir production capacity prediction accuracy on the basis of ensuring simplicity and ease of operation.

[0007] In the Chinese patent application with application number: CN201811158026.3, a method and system for standardizing well logging curves based on sedimentary phase constraints are involved. The method includes: determining the standard layer of the formation in the work area, selecting a standard well in each phase belt of the standard layer according to the analysis results of the sedimentary phase; obtaining the corresponding well logging curve correction amount in each phase belt according to the well logging curve of the standard well in each phase belt; correcting the well logging curve of the standard well in each phase belt according to the corresponding well logging curve correction amount to obtain the well logging curve of the corrected standard well; for the well logging curve of the target well in each phase belt, standardizing it according to the corresponding well logging curve of the corrected standard well to obtain the well logging curve of the standardized target well. Based on the actual data, the invention standardizes the well logging curves in the work area according to the phase belts, reasonably maintains the differences between the phase belts, uses the target layer sand body as the standard layer to standardize the well logging curves, eliminates the vertical non-geological factor errors, and provides reliable well logging data for seismic inversion.

[0008] The above existing technologies are all significantly different from the present invention and fail to solve the technical problem we want to solve. Therefore, we have invented a new reservoir prediction method based on sedimentary differences. Summary of the invention

[0009] The purpose of the present invention is to provide a reservoir prediction method based on sedimentary differences to solve the problems of low well control and high difficulty in predicting reservoirs in river phase narrow channels.

[0010] The object of the present invention can be achieved by the following technical measures: a reservoir prediction method based on sedimentary differences, the reservoir prediction method based on sedimentary differences comprising:

[0011] Step 1: Compare and analyze the drilling situation of a single well, obtain the reservoir thickness between each well, and classify the reservoir type;

[0012] Step 2, matching and analyzing the sedimentary differences developed in different strata with the reservoir types in step 1;

[0013] Step 3, based on the matching results, restore the river channel positions at different deposition periods;

[0014] Step 4: Use the method of extracting seismic attributes combined with the river channel location to predict the reservoir.

[0015] The purpose of the present invention can also be achieved by the following technical measures:

[0016] In step 1, a comparative analysis is conducted on the wells drilled in the area, a well-connected profile is established, the reservoir thickness between the wells is obtained, and the reservoir type is classified in combination with the sedimentary microfacies.

[0017] In step 1, the reservoir is divided into type I reservoir, type II reservoir and non-reservoir.

[0018] In step 2, a human-computer interaction method is used to combine well and seismic data. Based on the stratigraphic data, the seismic event energy intensity and event dip are used as the basis to perform sedimentary differentiation analysis on each target layer from bottom to top, and the sedimentary differences developed in different stratigraphic positions are matched with the reservoir types in step 1 for analysis.

[0019] In step 2, a combination of well and seismic data is used to finely calibrate the synthetic records of the wells drilled in the work area, finely describe the top and bottom structural morphology of the target layer, and restore the paleo-geomorphology of the sedimentary environment of the target layer. Using the principle of sedimentation compensation, the difference between the stratigraphic data of the first target layer and the overlying strata is used as the basic data for sedimentation difference analysis, and the energy changes and dip angle differences of the seismic phase axis are compared to match the differences with the reservoir types.

[0020] In step 2, the same method is used for the second target layer and above.

[0021] In step 3, the reservoir position and type in the well-free area are determined by sedimentary difference comparison, and compared with the reservoir in the well drilling position in step 2, and the reservoirs are classified to obtain a reservoir location map. The reservoir types are marked in the map, and the reservoirs are connected to obtain the river channel position and morphology of the first target layer.

[0022] In step 3, the same method is used for the second target layer and above.

[0023] In step 4, the attribute difference is obtained by extracting the seismic amplitude attributes of the overlying strata and the first target layer.

[0024] In step 4, if the target block has a well area with a reservoir attribute value greater than 5000, the first target layer river channel distribution map is superimposed and combined with the marked reservoir type to perform reservoir prediction, providing a basis for the subsequent oil and gas field development.

[0025] The reservoir prediction method based on sedimentary differences in the present invention solves the problems of low well control and difficulty in predicting reservoirs in river phase narrow channels, provides a reservoir prediction method with high accuracy for development zones, and provides a basis for detailed description of reservoirs. The reservoir prediction method based on sedimentary differences described in the present invention adopts the principle of "sedimentary compensation", makes full use of sedimentary difference analysis and reservoir types, restores the channel positions of different sedimentary periods, and predicts reservoir development and distribution in combination with seismic attributes, significantly improves the accuracy of reservoir prediction, solves the technical difficulties of predicting reservoirs in river phase narrow channels with low well control, and the reservoir prediction results provided by this method have achieved good application effects, and the use of this technology has improved the well site deployment and implementation effects, and the actual reservoir drilling distribution has a high consistency with the prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A schematic diagram of the classification of reservoir types of typical wells in a specific embodiment of the present invention;

[0027] Figure 2 A schematic diagram showing a comparison of deposition differences in typical wells in a specific embodiment of the present invention;

[0028] Figure 3 A river channel distribution diagram of the first target layer in a specific embodiment of the present invention;

[0029] Figure 4 It is a superposition diagram of difference amplitude attribute and river channel distribution in a specific embodiment of the present invention;

[0030] Figure 5 The flowchart is a specific embodiment of the reservoir prediction method based on sedimentary differences of the present invention. 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] The reservoir prediction method based on sedimentary differences of the present invention comprises the following steps: 1. comparing and analyzing the drilling conditions of a single well, obtaining the reservoir thickness between the wells, and classifying the reservoir types; 2. adopting a human-computer interaction method, combining well and seismic data, and based on the stratigraphic data, taking the seismic event energy intensity and the event dip as the basis, performing sedimentary differential analysis on each target layer from bottom to top, and matching and analyzing the sedimentary differences developed in different stratigraphic positions with the reservoir types in step 1; 3. restoring the river channel positions in different sedimentary periods according to the matching results; and 4. performing reservoir prediction by combining the river channel positions with the method of extracting seismic attributes.

[0034] The following are several specific embodiments of the present invention.

[0035] Example 1

[0036] In a specific embodiment 1 of the present invention, Figure 5 As shown, Figure 5 The flowchart of a specific embodiment of the reservoir prediction method based on sedimentary differences of the present invention is as follows. The reservoir prediction method based on sedimentary differences includes the following steps:

[0037] Step 101, conduct comparative analysis on the wells drilled in the upper section of Zhongguan in the region, establish a well-connected profile, obtain the reservoir thickness between the wells, and classify the reservoir into Class I reservoir, Class II reservoir, non-reservoir, etc. based on the sedimentary microfacies.

[0038] Step 102, adopt the method of combining well and seismic data to finely calibrate the synthetic records of the wells drilled in the work area, finely describe the top and bottom structural morphology of the target layer, restore the paleo-geomorphology of the sedimentary environment of the target layer, and use the principle of sedimentation compensation to use the difference between the stratigraphic data of the first target layer and the overlying strata as the basic data for sedimentation difference analysis, compare the energy changes and dip differences of the seismic phase axis, and match the differences with the reservoir type. The same method is used for the second target layer and above.

[0039] Step 103, by comparing the sedimentary differences, determine the reservoir position and type in the well-free area, compare and match with the reservoir in the well drilling position in step 102, classify the reservoirs, and then obtain a reservoir position map, mark the reservoir type in the map, connect the reservoirs, and obtain the river channel position and morphology of the first target layer. The same method is used for the second target layer and above.

[0040] Step 104, by extracting the seismic amplitude attributes of the overlying strata and the first target layer along the layer, the attribute difference is obtained. The target block has a well area with a reservoir attribute value greater than 5000. The river channel distribution map of the first target layer is superimposed and combined with the marked reservoir type to perform reservoir prediction. 15 wells are designed in the target area, and the estimated reserves are 5.3 million tons.

[0041] Example 2

[0042] In a specific embodiment 2 of the present invention, the reservoir prediction method based on sedimentary differences includes the following steps:

[0043] (1) Comparative analysis of wells drilled in the upper section of the pavilion in the region. Figure 1 , establish a well-connected profile, obtain the reservoir thickness between each well, and divide the reservoir types based on the sedimentary microfacies. The center of the river channel is the first type of reservoir, and the edge is the second type of reservoir.

[0044] (2) Figure 2 The synthetic records of the wells drilled in the work area were finely calibrated by combining well and seismic data. The interpreted structural layer data and the sedimentation compensation principle were used to take the difference between the layer data of the first target layer and the overlying strata as the basic data for sedimentation difference analysis. The energy changes and dip angle differences of the seismic event axis were compared, and the differences were matched with the reservoir types. The same method was used for the second target layer and above.

[0045] (3) Figure 3By comparing the sedimentary differences, the reservoir position and type in the well-free area are determined, and a reservoir position map is obtained. The reservoir type is marked in the map, and the reservoirs are connected to obtain the river channel position and morphology of the first target layer. The same method is used for the second target layer and above.

[0046] (4) Figure 4 By extracting the seismic amplitude attributes of the overlying strata and the first target layer along the layer, the first type of reservoir obtained a value greater than 4000, and the second type of reservoir was between 1000 and 4000. The river channel distribution map of the first target layer was superimposed and combined with the marked reservoir type to perform reservoir prediction. Four directional wells were deployed in the target area, with an average daily oil production of 30-40t / d.

[0047] Example 3

[0048] In a specific embodiment 3 of the present invention, the reservoir prediction method based on sedimentary differences includes the following steps:

[0049] Step 101, conduct comparative analysis on the wells drilled in the upper section of Zhongguan in the region, establish a well-connected profile, obtain the reservoir thickness between the wells, and classify the reservoir into Class I reservoir, Class II reservoir, non-reservoir, etc. based on the sedimentary microfacies.

[0050] Step 102, adopt the method of combining well and seismic data to finely calibrate the synthetic records of the wells drilled in the work area, finely describe the top and bottom structural morphology of the target layer, restore the paleo-geomorphology of the sedimentary environment of the target layer, and use the principle of sedimentation compensation to use the difference between the stratigraphic data of the first target layer and the overlying strata as the basic data for sedimentation difference analysis, compare the energy changes and dip differences of the seismic phase axis, and match the differences with the reservoir type. The same method is used for the second target layer and above.

[0051] Step 103, by comparing the sedimentary differences, determine the reservoir position and type in the well-free area, compare and match with the reservoir in the well drilling position in step 102, classify the reservoirs, and then obtain a reservoir position map, mark the reservoir type in the map, connect the reservoirs, and obtain the river channel position and morphology of the first target layer. The same method is used for the second target layer and above.

[0052] Step 104, by extracting the seismic amplitude attributes of the overlying strata and the first target layer along the layer, the attribute difference is obtained. The target block has a well area with a reservoir attribute value greater than 4500. The river channel distribution map of the first target layer is superimposed and combined with the marked reservoir type to perform reservoir prediction. Five wells are designed in the target area, and the estimated reserves are 1.97 million tons.

[0053] Example 4

[0054] In a specific embodiment 4 of the present invention, the reservoir prediction method based on sedimentary differences includes the following steps:

[0055] (1) Comparative analysis of wells drilled in the upper section of the pavilion in the region. Figure 1 , establish a well-connected profile, obtain the reservoir thickness between each well, and divide the reservoir types based on the sedimentary microfacies. The center of the river channel is the first type of reservoir, and the edge is the second type of reservoir.

[0056] (2) Figure 2 The synthetic records of the wells drilled in the work area were finely calibrated by combining well and seismic data. The interpreted structural layer data and the sedimentation compensation principle were used to take the difference between the layer data of the first target layer and the overlying strata as the basic data for sedimentation difference analysis. The energy changes and dip angle differences of the seismic event axis were compared, and the differences were matched with the reservoir types. The same method was used for the second target layer and above.

[0057] (3) Figure 3 By comparing the sedimentary differences, the reservoir position and type in the well-free area are determined, and a reservoir position map is obtained. The reservoir type is marked in the map, and the reservoirs are connected to obtain the river channel position and morphology of the first target layer. The same method is used for the second target layer and above.

[0058] (4) Figure 4 By extracting the seismic amplitude attributes of the overlying strata and the first target layer along the layer, the first type of reservoir obtained a value greater than 4000, and the second type of reservoir was between 1500 and 3500. The reservoir prediction was carried out by superimposing the river channel distribution map of the first target layer and combining it with the marked reservoir type. It is planned to deploy 4 directional wells in the target area, and the estimated reserves are 3 million tons.

[0059] 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.

[0060] 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 reservoir prediction method based on sedimentary differences, characterized in that: The reservoir prediction method based on sedimentary differences includes: Step 1: Compare and analyze the drilling situation of a single well, obtain the reservoir thickness between each well, and classify the reservoir type; Step 2, matching and analyzing the sedimentary differences developed in different strata with the reservoir types in step 1; Step 3, based on the matching results, restore the river channel positions at different deposition periods; Step 4: Use the method of extracting seismic attributes combined with the river channel location to predict the reservoir.

2. The reservoir prediction method based on sedimentary differences according to claim 1, characterized in that: In step 1, a comparative analysis is conducted on the wells drilled in the area, a well-connected profile is established, the reservoir thickness between the wells is obtained, and the reservoir type is classified in combination with the sedimentary microfacies.

3. The reservoir prediction method based on sedimentary differences according to claim 2, characterized in that: In step 1, the reservoir is divided into type I reservoir, type II reservoir and non-reservoir.

4. The reservoir prediction method based on sedimentary differences according to claim 1, characterized in that: In step 2, a human-computer interaction method is used to combine well and seismic data. Based on the stratigraphic data, the seismic event energy intensity and event dip are used as the basis to perform sedimentary differentiation analysis on each target layer from bottom to top, and the sedimentary differences developed in different stratigraphic positions are matched with the reservoir types in step 1 for analysis.

5. The reservoir prediction method based on sedimentary differences according to claim 4, characterized in that: In step 2, a combination of well and seismic data is used to finely calibrate the synthetic records of the wells drilled in the work area, finely describe the top and bottom structural morphology of the target layer, and restore the paleo-geomorphology of the sedimentary environment of the target layer. Using the principle of sedimentation compensation, the difference between the stratigraphic data of the first target layer and the overlying strata is used as the basic data for sedimentation difference analysis, and the energy changes and dip angle differences of the seismic phase axis are compared to match the differences with the reservoir types.

6. The reservoir prediction method based on sedimentary differences according to claim 5, characterized in that: In step 2, the same method is used for the second target layer and above.

7. The reservoir prediction method based on sedimentary differences according to claim 1, characterized in that: In step 3, the reservoir position and type in the well-free area are determined by sedimentary difference comparison, and compared with the reservoir in the well drilling position in step 2, and the reservoirs are classified to obtain a reservoir location map. The reservoir types are marked in the map, and the reservoirs are connected to obtain the river channel position and morphology of the first target layer.

8. The reservoir prediction method based on sedimentary differences according to claim 7, characterized in that: In step 3, the same method is used for the second target layer and above.

9. The reservoir prediction method based on sedimentary differences according to claim 1, characterized in that: In step 4, the attribute difference is obtained by extracting the seismic amplitude attributes of the overlying strata and the first target layer.

10. The reservoir prediction method based on sedimentary differences according to claim 9, characterized in that: In step 4, if the target block has a well area with a reservoir attribute value greater than 5000, the first target layer river channel distribution map is superimposed and combined with the marked reservoir type to perform reservoir prediction, providing a basis for the subsequent oil and gas field development.

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