Method and system for constructing a framework model of a gas hydrate reservoir mound morphology

Abstract

The application discloses a method and system for constructing a framework model of a gas hydrate reservoir mound form, which comprises the following steps: locking a hydrate reservoir overall framework containing key layer markers according to three-dimensional seismic data, core experiment data, logging and well logging data of a region to be researched, wherein the key layer markers comprise a free gas cap, a BRS surface and a hydrate bottom; obtaining well distribution and regional tectonic seismic interpretation data, and determining edge change characteristics of a current hydrate reservoir in combination with a hydrate development rule; establishing a thickness control chart of each key layer and constructing a zero-thickness control point according to the edge change characteristics and the reservoir overall framework; establishing a layer surface model of each key layer surface according to the reservoir overall framework, the thickness control chart and the zero-thickness control point; and integrating each layer surface model and combining key layer thickness and a reservoir enrichment degree to form a hydrate reservoir framework model. The framework model constructed by the application is more in line with actual geological characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mineral and energy exploration and development, and particularly relates to a method and system for constructing a gas hydrate reservoir mound form framework model. BACKGROUND

[0002] The gas hydrate reservoir has many characteristics such as high energy density, wide distribution, shallow burial, and superior accumulation physical and chemical conditions. It is expected to become the most ideal new energy with commercial development prospects in the 21st century, and also has important significance in global environmental change.

[0003] At present, there are few technical data for modeling the gas hydrate reservoir. In the modeling field, the framework model is the premise of subsequent modeling, and there are even fewer related data for the hydrate framework geological model. Therefore, it is of great significance to establish a high-precision hydrate framework model and form a method for the hydrate framework model, so as to truly connect the "bridge" between hydrate exploration and development. In the process of realizing the present application, the inventors found that in the existing hydrate modeling technology, the hydrate stratigraphic model is mainly established by constructing hydrate key layers according to a small amount of straight well stratification information. Although this can describe the edge thickness characteristics of the stratigraphic model to some extent, it does not conform to the mound form of the hydrate, thereby causing the reserve calculation result to be large, and causing certain difficulties for later well site design.

[0004] Therefore, the prior art needs to provide a construction scheme of a three-dimensional framework model conforming to the form of the hydrate reservoir, so that the constructed hydrate framework model can accurately describe the hydrate development characteristics in the study area. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a method for constructing a gas hydrate reservoir mound form framework model, comprising: locking a hydrate reservoir overall framework containing key layer markers in a current area according to three-dimensional seismic data, core experiment data, and logging and well logging data of a to-be-studied area, the key layers including a free gas cap, a BSR surface, and a hydrate bottom surface; obtaining well distribution characteristics and regional tectonic seismic interpretation data in the current area, and determining edge variation characteristics of the current hydrate reservoir in combination with hydrate development rules; establishing a thickness control chart of each key layer and constructing a zero thickness control point according to the edge variation characteristics and the hydrate reservoir overall framework; respectively establishing a layer model of each key layer according to the hydrate reservoir overall framework, the thickness control chart, and the zero thickness control point; and integrating the layer models and combining key layer thickness and reservoir enrichment degree to form a hydrate reservoir framework model.

[0006] Preferably, before the integration of each key layer model, the method further comprises: profile drawing processing of each key layer model, and detecting whether the matching relationship between each key layer is consistent with the geological characteristics of the area where the hydrate reservoir is located, and when the detection is passed, the integration of each key layer model is performed.

[0007] Preferably, in the case of detection failure, the edge thinning trend in the edge change feature is re-identified.

[0008] Preferably, the key layer of the hydrate reservoir in the current area is identified according to the three-dimensional seismic data of the area to be studied; the stratigraphic horizon of the straight well in the current area is divided by using the core experimental data and the logging and well logging data, and the position of each key layer based on seismic interpretation is corrected by using the horizon division result; the key layer map of the hydrate reservoir is established and integrated to form the overall framework of the hydrate reservoir.

[0009] Preferably, according to the key layer based on the seismic interpretation after the horizon correction, the discrete smooth interpolation method is used to establish the key layer map of the hydrate reservoir.

[0010] Preferably, according to the thickness of the free gas layer, the thickness of the hydrate solid layer and the enrichment degree information of the hydrate reservoir, the longitudinal grid accuracy required for the framework model is set, and the integrated layer model is gridded according to the longitudinal grid accuracy, so as to generate the hydrate reservoir framework model.

[0011] Preferably, according to the edge thinning trend distribution feature in the edge change feature, the intersection of the extension lines of each key layer at each edge thinning trend is determined as the zero thickness position of the current thinning trend to form the zero thickness control point.

[0012] In another aspect, the present application also provides a system for constructing a framework model of a gas hydrate reservoir mound form, comprising: a general framework generation module configured to lock a general framework of a hydrate reservoir containing key layer markers in a current region according to three-dimensional seismic data, core experiment data, and logging data of a region to be studied, wherein the key layer markers include a free gas cap, a BSR surface, and a hydrate bottom surface; an edge feature generation module configured to obtain well distribution features and regional tectonic seismic interpretation data in the current region, and determine edge change features of the current hydrate reservoir in combination with a hydrate development rule; a constraint condition generation module configured to establish a thickness control chart for each key layer and construct zero thickness control points according to the edge change features and the general framework of the hydrate reservoir; a layer model generation module configured to establish a layer model for each key layer according to the general framework of the hydrate reservoir, the thickness control chart, and the zero thickness control points; and a framework model generation module configured to integrate the layer models and form a hydrate reservoir framework model in combination with key layer thicknesses and reservoir enrichment degrees.

[0013] Preferably, the framework model generation module is further configured to perform profile pulling processing on the layer model of each key layer, and detect whether a matching relationship between the layers meets geological features of a region where the hydrate reservoir is located, and when the detection passes, integrate the layer models.

[0014] Preferably, the general framework generation module comprises: a key layer marker identification unit configured to identify key layer markers of a hydrate reservoir in a current region according to three-dimensional seismic data of a region to be studied; a key layer marker position correction unit configured to perform stratigraphic horizon division on a straight well in the current region by using the core experiment data and the logging data, and correct positions of each key layer marker based on seismic interpretation by using a horizon division result; and a key layer marker integration unit configured to establish a key layer marker chart of the hydrate reservoir and form the general framework of the hydrate reservoir after integration.

[0015] Compared with the prior art, one or more embodiments in the above solution can have the following advantages or beneficial effects:

[0016] The application discloses a method and system for constructing a gas hydrate reservoir mound form framework model. The application solves the problem that a hydrate framework model is not constructed by considering the hydrate form in the prior art, constructs the framework model by taking the mound form of the hydrate reservoir as a target layer, and is higher in model precision; meanwhile, the problem that the prior gas hydrate model seldom considers the form of the edge part is solved, and the matching problem between various key layers is solved, information of the control points and the thickness map is effectively utilized, the framework model is more in line with the actual geological characteristics, and the framework model is constructed by effectively combining the structural interpretation on the seismic of the research area with drilling stratification, the information of the geologist and the like, thereby reducing the uncertainty of the whole set of hydrate geological modeling, and being helpful for analyzing the geological law, calculating the reserves, optimizing the well site deployment and improving the drilling rate, and the subsequent reservoir attribute modeling can be performed through the modeling platform, and a more reliable model guarantee is provided for effective development of the gas hydrate.

[0017] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate embodiments of the present application and explain the present application together with the written description, and do not limit the present application. In the drawings:

[0019] Figure 1 is a step diagram of the method for constructing the gas hydrate reservoir mound form framework model of the embodiment of the present application.

[0020] Figure 2 is a specific flowchart of the method for constructing the gas hydrate reservoir mound form framework model of the embodiment of the present application.

[0021] Figure 3 is an identification result schematic diagram of the free gas top, the BSR layer and the hydrate solid layer determined based on the seismic interpretation in the method for constructing the gas hydrate reservoir mound form framework model of the embodiment of the present application.

[0022] Figure 4It is a schematic diagram of a hydrate reservoir key layer framework in a method for constructing a hydrate reservoir mound morphology framework model according to an embodiment of the present application.

[0023] Figure 5 It is a schematic diagram of a zero-thickness position point identification principle in a method for constructing a hydrate reservoir mound morphology framework model according to an embodiment of the present application.

[0024] Figure 6 It is an example diagram of an equal-thickness control chart of free gas and hydrate solid layers in a method for constructing a hydrate reservoir mound morphology framework model according to an embodiment of the present application.

[0025] Figure 7 It is a schematic diagram of an identification effect of a zero-thickness control point in a method for constructing a hydrate reservoir mound morphology framework model according to an embodiment of the present application.

[0026] Figure 8 It is a profile schematic diagram of a hydrate layer model in a method for constructing a hydrate reservoir mound morphology framework model according to an embodiment of the present application.

[0027] Figure 9 It is a schematic diagram of a hydrate reservoir mound morphology three-dimensional framework model in a method for constructing a hydrate reservoir mound morphology framework model according to an embodiment of the present application.

[0028] Figure 10 It is a module block diagram of a system for constructing a hydrate reservoir mound morphology framework model according to an embodiment of the present application. DETAILED DESCRIPTION

[0029] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and embodiments, so that how the present application applies technical means to solve technical problems and achieves technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, each embodiment in the present application and each feature in each embodiment can be combined with each other, and the technical solutions formed thereby are all within the protection scope of the present application.

[0030] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a group of computer executable instructions. Moreover, although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0031] The hydrate reservoir has many characteristics such as high energy density, wide distribution, shallow burial, and superior accumulation physical and chemical conditions. It not only has the potential to become the most ideal new energy with commercial development prospects in the twenty-first century, but also has important significance in global environmental change.

[0032] At present, there are few technical materials for modeling of natural gas hydrate reservoirs, and in the field of modeling, a framework model is a prerequisite for subsequent modeling, and there are even fewer relevant materials for a hydrate framework geological model, so it is of great significance to establish a high-precision hydrate framework model, form a method for forming a hydrate framework model, and make it truly connect the 'bridge' between hydrate exploration and development. In the process of realizing the present application, the inventors found that in the existing hydrate modeling technology, a hydrate formation model is established mainly on the basis of a small amount of straight well stratification information to construct a hydrate key layer surface, which can depict the edge thickness characteristics of the formation model to a certain extent, but does not conform to the mound shape of the hydrate, thereby causing the calculated reserves to be larger, and causing certain difficulties for later well site design.

[0033] Therefore, the prior art needs to provide a construction scheme of a three-dimensional framework model conforming to the shape of a hydrate reservoir. In order to solve the above technical problems, the present application proposes a method and system for constructing a natural gas hydrate reservoir mound shape framework model. The method and system comprise: locking a hydrate reservoir overall framework containing key layer markers in the current region according to three-dimensional seismic data, core experiment data and logging and well logging data of the region to be studied, wherein the key layer includes a free gas cap, a BSR surface and a hydrate bottom surface; then, based on the hydrate development law, the well distribution characteristics and regional tectonic seismic interpretation data in the current region are determined to determine the edge variation characteristics of the current hydrate reservoir; then, according to the determined reservoir edge variation characteristics and the hydrate reservoir overall framework, a thickness control chart of the free gas layer and a thickness control chart of the hydrate solid layer composed of each key layer are established respectively, based on which, a zero thickness control point is constructed; according to the hydrate reservoir overall framework, the thickness control chart of the free gas and hydrate solid layer and the zero thickness control point, a layer model of each key layer is established respectively; after integrating each layer model and marking the key layer thickness and enrichment degree, a hydrate reservoir framework model is formed.

[0034] In this way, the hydrate framework model generated by the framework model construction scheme provided by the present application can accurately describe the hydrate development characteristics in the study region, including the hydrate reservoir tectonic fluctuation, the hydrate thickness variation and the like, and better reflect the spatial distribution characteristics of the hydrate inside, thereby solving the problem of the few cracking edge shapes of the traditional hydrate model and the matching problem between each small layer (the free gas layer surface, the BSR layer surface and the hydrate bottom surface), and providing more reliable model guarantee for effective development of natural gas hydrate.

[0035] Figure 1 is a step diagram of the method for constructing a natural gas hydrate reservoir mound shape framework model according to an embodiment of the present application. Figure 2is a specific flowchart of the method for constructing a framework model of a gas hydrate reservoir mound form according to an embodiment of the present application. The method for constructing a framework model of a gas hydrate reservoir mound form according to an embodiment of the present application will be described below in combination with Figure 1 and Figure 2 The method for constructing a framework model of a gas hydrate reservoir mound form according to an embodiment of the present application will be described below in combination with

[0036] In step S110, the overall framework of the hydrate reservoir containing key layer markers in the current region is locked according to the three-dimensional seismic data, core experiment data, and logging data of the region to be studied. The key layers include the free gas cap, BSR, and hydrate bottom.

[0037] Specifically, in step S110, first (step S1101, not shown), the key layers of the hydrate reservoir in the current region are identified according to the three-dimensional seismic data of the region to be studied. After obtaining the three-dimensional seismic data of the region to be studied, the seismic layer interpretation of the current region is performed, and the (all) free gas cap, (all) BSR, and (all) hydrate bottom of the hydrate reservoir in the current region to be studied are identified, thereby obtaining the free gas cap seismic interpretation map, BSR seismic interpretation map, and hydrate bottom seismic interpretation map, respectively.

[0038] Figure 3 is an identification result diagram of the free gas cap, BSR layer, and hydrate solid layer determined based on the seismic interpretation in the method for constructing a framework model of a gas hydrate reservoir mound form according to an embodiment of the present application. As shown in Figure 3 from left to right, respectively, the corresponding examples of the free gas cap seismic interpretation map, BSR seismic interpretation map, and hydrate bottom seismic interpretation map are shown. For the three relatively certain free gas cap, BSR, and hydrate bottom interpreted by the seismic interpretation, the three layers have relatively clear seismic axis and are easy to interpret, and the range of the middle part of the hydrate reservoir can be determined according to the three layers. The range of the hydrate reservoir determined based on the three layers is generally relatively small relative to the overall hydrate reservoir, and therefore, the establishment of the edge features needs to be performed subsequently.

[0039] Then, (step S1102, not shown) using the core experimental data, logging data and logging data for the area to be studied, the straight well in the current area to be studied is stratigraphic horizon division, and the position of each key layer based on seismic interpretation is corrected using the stratigraphic horizon division result. Specifically, in the embodiment of the present application, in order to obtain accurate well stratification data, it is necessary to first obtain the core data, logging cuttings and logging data of the current area to be studied, to carry out stratigraphic horizon division based on the straight well for the area to be studied, and to obtain the corresponding stratigraphic horizon division result. Further, using the current obtained stratigraphic horizon division result (drilling stratification data), the position of each key layer of the current hydrate reservoir based on seismic interpretation is corrected, so as to mark the stratigraphic horizon division data in the free gas top layer seismic interpretation graph, the BSR layer seismic interpretation graph and the hydrate bottom surface seismic interpretation graph, respectively, so that each key layer seismic interpretation graph obtains more accurate position characteristics, thereby determining the position of the free gas layer and the hydrate solid layer.

[0040] In actual application process, since the accuracy of the positions of the free gas top, the BSR surface and the hydrate bottom surface identified based on seismic interpretation is insufficient to complete the accuracy requirement of the framework model, therefore, it is necessary to correct the position of each key layer of the hydrate reservoir using the accurate stratigraphic horizon division data obtained by drilling and logging data, so as to determine the accurate position of the key layer.

[0041] It should be noted that the key layer described in the embodiment of the present application refers to the layer formed between different key layers. Since the key layer is formed between different layers, it has a certain thickness, and the thickness at different positions in the same key layer is also different. Among them, the free gas layer is the layer formed between the free gas top layer and the BSR surface. The hydrate solid layer is the layer formed between the hydrate bottom surface and the BSR surface.

[0042] After completing the stratigraphic horizon correction, (step S1103, not shown) the key layer surface graph of the hydrate reservoir is established, and each key layer surface graph is integrated to form the overall framework of the hydrate reservoir. Specifically, after obtaining each key layer surface seismic interpretation graph after stratigraphic horizon correction, a discrete smoothing interpolation method is used to establish a corresponding layer surface graph for each key layer. In this way, the free gas top surface seismic interpretation graph, the BSR surface seismic interpretation graph and the hydrate bottom surface seismic interpretation graph identified by seismic interpretation are converted into smooth and relatively smooth layer surface graphs, i.e. free gas top surface graph, BSR surface graph and hydrate bottom surface graph. Then, after completing the construction of the key layer surface graph of the hydrate reservoir, according to the position distribution characteristics of the accurate layer surface and the internal position points, the various key layer surface graphs are integrated together to form the overall framework of the hydrate reservoir. Figure 4is a schematic diagram of a hydrate reservoir key layer framework in a method for constructing a hydrate reservoir mound form framework model according to an embodiment of the present application. In the overall framework, the accurate stratification information at different positions in the hydrate reservoir, the accurate position distribution information of different key layer positions, the position relationship between different key layers, and other characteristics are marked respectively.

[0043] After the overall framework of the hydrate reservoir is formed, the model construction for the obvious internal characteristics of the hydrate reservoir is completed, so as to enter step S120 to identify the edge characteristics of the hydrate reservoir in the current region to be studied. Step S120 determines the edge change characteristics of the current hydrate reservoir based on the hydrate development law, in combination with the well distribution characteristics in the current region and the regional tectonic seismic interpretation data.

[0044] In step S120, first, the well distribution characteristic data in the current region to be studied and the seismic interpretation data of the internal geological structure of the current region to be studied (especially, the seismic interpretation data of the internal geological structure trend of the region) are obtained, and then the edge change characteristics of the hydrate reservoir in the current region are identified based on the well distribution characteristics and the regional tectonic seismic interpretation data, in combination with the hydrate reservoir development law of the current region to be studied and based on the overall framework of the hydrate reservoir constructed in step S110. Specifically, from the overall framework of the hydrate reservoir, the reservoir edge change characteristics (including the gradually thinning part and the gradually thickening part) are first identified, and then the positions with the gradually thinning trend characteristics are identified from the edge change characteristics, so as to enter step S130.

[0045] Step S130 establishes the thickness control chart of each key layer based on the edge change characteristics identified in step S120 and the overall framework of the hydrate reservoir constructed in step S110, and based on this, further constructs the zero thickness control point required for constructing the framework model.

[0046] In step S130, first, the positions with the gradually thinning trend in the edge change characteristics are obtained based on the edge change characteristics identified in step S120 and the overall framework of the hydrate reservoir constructed in step S110. The positions with the gradually thinning trend characteristics are first determined from the overall framework of the hydrate reservoir, denoted as the edge thinning trend, so that the edge thinning trend distribution characteristics are marked in the overall framework of the hydrate reservoir. In the embodiment of the application, the edge thinning trend refers to the part where the thickness of each key layer gradually decreases, and the reference Figure 5 Figure 5 ​is the upper half of the diagram in the identification principle of zero-thickness position points in the method for constructing a framework model of the mound morphology of a natural gas hydrate reservoir according to an embodiment of the present application. In the diagram, the part in the dashed box represents the part corresponding to the edge thinning trend. Then, according to the distribution characteristics of the edge thinning trend, the intersection point of the extension lines of each key layer at each edge thinning trend is determined as the zero-thickness position of the current thinning trend (the zero-thickness position includes the zero-thickness position coordinates and the depth), to form the following zero-thickness control points. The zero-thickness position represents the development boundary of each key layer in the hydrate reservoir. In this way, after marking the zero-thickness positions corresponding to different edge thinning trends in the overall framework, the overall framework with obvious internal characteristics of the reservoir is subjected to the edge range expansion and edge limit definition operation, and the description range of the obvious hydrate characteristics is expanded to a certain extent, to the boundary range of the development zero-thickness points of each key layer in the simulated reservoir (i.e., the range constrained by the set of each zero-thickness position point).

[0047] Next, from the hydrate reservoir overall framework marked with the zero-thickness position information corresponding to different edge thinning trends, the thickness control diagrams of the layer thickness variation characteristics at different positions in the free gas layer (i.e., the free gas layer thickness control diagram) and the thickness control diagrams of the layer thickness variation characteristics at different positions in the hydrate solid layer (i.e., the hydrate solid layer thickness control diagram) are extracted. Specifically, according to the position difference between different key layers in the hydrate reservoir overall framework, the layer thickness variation characteristics at different positions in the free gas layer and the layer thickness variation characteristics at different positions in the hydrate solid layer are obtained respectively, to form the corresponding free gas layer thickness control diagram and hydrate solid layer thickness control diagram. In this way, the edge thickness constraint condition required for constructing the framework model is obtained. At this time, the thickness variation characteristics of each thickness control diagram is a thickness constraint diagram in which the thickness is zero from the middle part of the key layer to the boundary.

[0048] Figure 6 is an example diagram of the isopach control diagram of the free gas layer and the hydrate solid layer in the method for constructing a framework model of the mound morphology of a natural gas hydrate reservoir according to an embodiment of the present application. As shown in Figure 6 , an example diagram of the free gas layer thickness control diagram and the hydrate solid layer thickness control diagram is shown from left to right.

[0049] In addition, the embodiment of the present application also needs to construct zero-thickness control points in step S130 to assign these control points as reservoir edge features to the extension reference of the overall framework, i.e., the edge range reference constraint condition. Specifically, after determining the zero-thickness positions corresponding to all edge thinning trends, a series of zero-thickness position points are formed in the hydrate reservoir overall framework marked with zero-thickness position information corresponding to different edge thinning trends, and these zero-thickness position points are combined to form zero-thickness control points to mark the zero-thickness control points in the hydrate reservoir overall framework. At this time, since the zero-thickness control points (series) constructed by the embodiment of the present application are composed of zero-thickness position points at different positions, the more the number of identified edge thinning trends, the more the number of zero-thickness position points, the more dense the formed zero-thickness control points, and the better the subsequent layer model construction effect.

[0050] Figure 7 is a schematic diagram of the identification effect of the zero-thickness control points in the method for constructing a hydrate reservoir hill-shaped framework model according to an embodiment of the present application. As shown in Figure 7 from left to right, the corresponding free gas top surface map, BSR map and hydrate bottom surface map in the hydrate reservoir overall framework constructed based on step S110 and not marked with edge change features and zero-thickness control points are shown, and the position relationship between the series of zero-thickness control points and each layer is shown in the periphery of the corresponding layer map.

[0051] With reference to Figure 1 and Figure 2 , after the establishment of the thickness constraint condition of the key layer and the reservoir boundary range condition of the zero-thickness position points is completed, step S140 is entered. In step S140, the layer model of each key layer is established according to the hydrate reservoir overall framework, the free gas layer thickness control map, the hydrate solid layer thickness control map and the zero-thickness control points.

[0052] In step S140, the layer model of each key layer is established according to the free gas layer thickness control map, the hydrate solid layer thickness control map and the hydrate reservoir overall framework marked with the series of zero-thickness position points, with the data shown by the key layer in the overall framework as the condition data, with the free gas layer thickness control map and the hydrate solid layer thickness control map as the reservoir edge thickness change constraint condition, and with the series of zero-thickness position points marked in the overall framework as the reservoir boundary constraint condition, i.e., the free gas top surface layer model, the BSR surface layer model and the hydrate bottom surface layer model are obtained, so that each layer model established has edge thickness change features and edge boundary features, and the hydrate framework model constructed based on the three types of layer models considers the edge shape and edge boundary features, and a framework model more consistent with the actual geological understanding is obtained.

[0053] After the completion of the layer model construction, enter step S150. Step S150 integrates each layer model obtained in step S140, and combines the key layer thickness and the reservoir enrichment degree to form a hydrate reservoir framework model. In step S150, first, the free gas top surface layer model, the BSR surface layer model and the hydrate bottom surface layer model containing the edge thickness variation characteristics and the edge boundary range characteristics are obtained, and these layer models are integrated to obtain the hydrate layer model, as shown in FIG. 2. Figure 8 Figure 8 FIG. 2 is a profile schematic diagram of the hydrate layer model in the method for constructing the hydrate reservoir mound morphology framework model according to the embodiments of the present application.

[0054] Then, according to the enrichment degree distribution data of the hydrate reservoir in the current area to be studied, and the thickness variation characteristics (free gas layer thickness control chart, hydrate solid layer thickness control chart) of each key layer in the reservoir, the longitudinal grid accuracy required for the framework model construction operation is set, and the integrated layer model is gridded according to the set longitudinal grid accuracy (for example, the accuracy can be 0.25-0.5 m), so as to generate the hydrate reservoir framework model, as shown in FIG. 3. Figure 9 Figure 9 FIG. 3 is a schematic diagram of the hydrate reservoir mound morphology three-dimensional framework model in the method for constructing the hydrate reservoir mound morphology framework model according to the embodiments of the present application. At this time, the hydrate reservoir framework model obtained can fully and accurately show the mound morphology of the hydrate reservoir, so as to provide a more reliable structural framework for subsequent parameter model establishment.

[0055] In order to improve the accuracy and effectiveness of the integration processing and the matching degree of the integrated layer model and the actual geological characteristics, in the embodiments of the present application, the matching relationship between each layer model needs to be verified before the integration of each layer model. Specifically, the layer model of each key layer obtained in step S140 is subjected to profile pulling processing, and whether the matching relationship between each layer surface satisfies the geological feature conditions of the current hydrate reservoir area is detected. More specifically, when detecting the matching relationship, at least the following aspects need to be detected respectively: detecting whether the structural amplitude of each layer model satisfies the deposition characteristics of the current reservoir in geology, so that the structural amplitude of each layer model is not too large; detecting whether the edge of each layer model appears to be through the layer; detecting whether the overall morphology of each layer model conforms to the characteristics of the mound. Therefore, through the judgment of the foregoing at least three aspects, the hydrate layer model integrated from each layer model needs to match the actual well layering condition.

[0056] ​​If the detection result of each aspect is consistent, it is determined that the matching relationship between the generated layer models is consistent with the geological feature condition of the region where the hydrate reservoir is located, the detection is passed, and the layer models are integrated.

[0057] Specifically, in one embodiment, when the detection is passed, the layer models obtained in step S140 are integrated to obtain a hydrate layer model in which the matching relationship of different layers is consistent with the actual geological feature. In addition, when the detection is not passed, the step S120 is returned to, and the edge thinning trend in the edge feature is re-identified (for example, the scanning accuracy, the moving step length, and other information required for identifying the edge feature are adjusted).

[0058] The present application aims to depict the mound shape of the natural gas hydrate reservoir itself, corrects the overall framework of the hydrate by combining the shape information obtained through the structural interpretation on the earthquake and the geological research with the drilling stratification data, adding the boundary small layer control point data and the stratigraphic thickness control chart, and solves the problem that the traditional hydrate model rarely considers the edge shape and the matching problem between each small layer. The built natural gas hydrate framework model can better reflect the spatial distribution characteristics of the hydrate, increase the resolution of the overall hydrate geological modeling, reduce the uncertainty, more accurately reflect the distribution characteristics of the hydrate, provide an accurate framework model basis for subsequent reservoir attribute modeling, and provide a more reliable model guarantee for analyzing the geological law, optimizing the well location deployment, improving the drilling rate and the effective development of the natural gas hydrate.

[0059] On the other hand, based on the framework model construction method described above, the embodiment of the present application further provides a system for constructing a mound shape framework model of a natural gas hydrate reservoir (hereinafter referred to as a “framework model construction system”). Figure 10 is a module block diagram of the system for constructing a mound shape framework model of a natural gas hydrate reservoir according to the embodiment of the present application. As shown in Figure 10 The framework model construction system at least includes a general framework generation module 101, an edge feature generation module 102, a constraint condition generation module 103, a layer model generation module 104, and a framework model generation module 105.

[0060] Specifically, the overall framework generation module 101 is configured to lock the overall framework of the hydrate reservoir containing key layer markers in the current region according to the three-dimensional seismic data, core experiment data, and logging data of the region to be studied, wherein the key layer markers include the free gas cap, the BSR surface, and the hydrate bottom surface, and the overall framework generation module 101 is implemented according to the method described in step S110 above; the edge feature generation module 102 is configured to obtain the well distribution features and regional tectonic seismic interpretation data in the current region, and determine the edge change features of the current hydrate reservoir in combination with the hydrate development law, and the edge feature generation module 102 is implemented according to the method described in step S120 above; the constraint condition generation module 103 is configured to establish the thickness control chart of each key layer according to the edge change features and the overall framework of the hydrate reservoir, and further construct the zero-thickness control point, and the constraint condition generation module 103 is implemented according to the method described in step S130 above; the layer model generation module 104 is configured to establish the layer model of each key layer surface according to the overall framework of the hydrate reservoir, the thickness control chart, and the zero-thickness control point, and the layer model generation module 104 is implemented according to the method described in step S140 above; and the framework model generation module 105 is configured to integrate each layer model and form the hydrate reservoir framework model in combination with the key layer thickness and the reservoir enrichment degree, and the framework model generation module 105 is implemented according to the method described in step S150 above.

[0061] Further, the layer model verification module 105 is further configured to perform profile pulling processing on each key layer model, and detect whether the matching relationship between the layers meets the geological features of the region where the current hydrate reservoir is located, and when the detection passes, the layer models are integrated.

[0062] Further, the overall framework generation module 101 includes a key layer identification unit 1011, a key layer position correction unit 1012, and a key layer integration unit 1013. The key layer identification unit 1011 is configured to identify the key layer of the hydrate reservoir in the current region according to the three-dimensional seismic data of the region to be studied; the key layer position correction unit 1012 is configured to divide the formation layer position of the vertical well in the current region by using the core experiment data and the logging data, and correct the position of each key layer surface based on the seismic interpretation by using the layer position division result; and the key layer integration unit 1013 is configured to establish the key layer surface chart of the hydrate reservoir and form the overall framework of the hydrate reservoir after integration.

[0063] The application discloses a method and system for constructing a gas hydrate reservoir mound form framework model. The application solves the problem that a hydrate framework model is not constructed by considering the hydrate form in the prior art, constructs the framework model by taking the mound form of the hydrate reservoir as a target layer, and is higher in model precision; meanwhile, the application solves the problem that the prior art rarely considers the form of the edge part of a gas hydrate model, and solves the matching problem between various key layers, effectively utilizes the information of the control points and the thickness map calibration, and makes the framework model more in line with the actual geological characteristics; the framework model constructed by the application effectively combines the structural interpretation on the seismic of the research area, the drilling stratification, the information of the geologist's understanding and the like, reduces the uncertainty of the whole set of hydrate geological modeling, and is helpful for analyzing the geological law, calculating the reserves, optimizing the well site deployment and improving the drilling rate, can perform subsequent reservoir attribute modeling through a modeling platform, and provides a more reliable model guarantee for effective development of the gas hydrate.

[0064] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0065] It should be understood that the disclosed embodiments are not limited to the particular structures, process steps, or materials disclosed herein but are extended to equivalents thereof. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0066] Reference throughout this specification to "an embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.

[0067] Although the present application has been described with reference to the above embodiments, the contents described are only the embodiments adopted for facilitating the understanding of the present application, and are not intended to limit the present application. Any modification and change in the form and details of the present application can be made by any person skilled in the art without departing from the spirit and scope of the present application, and the patent protection scope of the present application shall be subject to the scope defined by the appended claims.

Claims

1. A method for constructing a framework model of a gas hydrate reservoir mound form, comprising: locking a general framework of a hydrate reservoir in a current area containing key layer markers according to three-dimensional seismic data, core experiment data, and logging data of an area to be studied, the key layer markers including a free gas cap, a BSR surface, and a hydrate bottom surface; acquiring well distribution characteristics in the current area and regional tectonic seismic interpretation data, and determining a thickness variation trend feature of an edge portion of a current hydrate reservoir including a gradually thinning portion and a gradually thickening portion in combination with a hydrate development law; extracting a thickness control chart representing a layer thickness variation trend feature at different positions in the free gas layer from the general framework of the hydrate reservoir according to the thickness variation trend feature of the edge portion and the general framework of the hydrate reservoir to be recorded as a free gas layer thickness control chart and extracting a hydrate solid layer thickness control chart representing a layer thickness variation trend feature at different positions in the hydrate solid layer, and constructing a zero thickness control point in the general framework of the hydrate reservoir marked with zero thickness position information corresponding to different edge portion thinning trend features, wherein the zero thickness control point is determined by determining an intersection point of an extension line of each key layer at each edge portion thinning trend as a zero thickness position of a current thinning trend according to an edge portion thinning trend distribution feature in the edge portion variation feature to form the zero thickness control point, and used to represent a development boundary of the free gas layer and the hydrate solid layer in the hydrate reservoir; establishing a free gas cap surface layer model, a BSR surface layer model, and a hydrate bottom surface layer model as reservoir edge portion thickness variation constraints and the zero thickness control point as a reservoir tectonic boundary constraint; performing profile pulling processing on the free gas cap surface layer model, the BSR surface layer model, and the hydrate bottom surface layer model, and detecting whether a tectonic amplitude of each layer model conforms to a geological deposition feature of a current reservoir, whether an edge portion of each layer model appears to be through the layer, and whether an overall form of each layer model conforms to a mound body feature, and when all three detections pass, integrating each layer model and combining key layer thickness and reservoir enrichment degree to form a hydrate reservoir framework model.

2. The method of claim 1, wherein, In the case of a failed detection, re-identifying an edge portion thinning trend in the edge portion variation feature.

3. The method of claim 1 or 2, wherein: key layer markers of a hydrate reservoir in a current area are identified according to three-dimensional seismic data of an area to be studied; straight wells in the current area are stratigraphically divided using the core experiment data and the logging data, and a position of each key layer based on seismic interpretation is corrected using a stratigraphic division result; a key layer chart of the hydrate reservoir is established and integrated to form the general framework of the hydrate reservoir.

4. The method of claim 3, wherein, the key layer chart of the hydrate reservoir is established using a discrete smoothing interpolation method based on each key layer based on seismic interpretation after stratigraphic correction.

5. The method of claim 1 or 2, wherein: According to the information of the hydrate reservoir framework model, the thickness of the free gas layer, the thickness of the hydrate solid layer and the enrichment degree of the hydrate reservoir, the longitudinal grid precision required by the framework model construction is set, and the integrated layer model is gridded according to the longitudinal grid precision, so as to generate the hydrate reservoir framework model.

6. A system for constructing a hydrate reservoir mound framework model, comprising: a general framework generation module configured to lock a hydrate reservoir general framework containing key layer markers in a current area according to three-dimensional seismic data, core experiment data and logging and well logging data of the area to be studied, the key layer including a free gas top, a BSR surface and a hydrate bottom surface; an edge feature generation module configured to obtain well distribution features and regional tectonic seismic interpretation data in the current area, and determine edge thickness variation trend features of the current hydrate reservoir including a gradually thinning part and a gradually thickening part in combination with a hydrate development rule; a constraint condition generation module configured to extract a thickness control chart representing layer thickness variation trend features at different positions in the free gas layer from the hydrate reservoir general framework to be marked as a free gas layer thickness control chart and extract a hydrate solid layer thickness control chart representing layer thickness variation trend features at different positions in the hydrate solid layer from the hydrate reservoir general framework according to the edge thickness variation trend features and the hydrate reservoir general framework, and construct zero thickness control points in the hydrate reservoir general framework marked with zero thickness position information corresponding to different edge thinning trend, wherein the zero thickness control points are determined by: according to the edge thinning trend distribution features in the edge variation features, determining the intersection point of the extension lines of each key layer at each edge thinning trend as the zero thickness position of the current thinning trend to form the zero thickness control points, so as to represent the development boundaries of the free gas layer and the hydrate solid layer in the hydrate reservoir; a layer model generation module configured to take the thickness control chart of the free gas layer and the thickness control chart of the hydrate solid layer as reservoir edge thickness variation constraint conditions and take the zero thickness control points to establish a free gas top surface layer model, a BSR surface layer model and a hydrate bottom surface layer model respectively; a framework model generation module configured to perform profile pulling processing on the free gas top surface layer model, the BSR surface layer model and the hydrate bottom surface layer model, and detect whether the tectonic amplitude of each layer model conforms to the geological deposition features of the current reservoir, whether the edge of each layer model appears through the layer and whether the overall morphology of each layer model conforms to the mound features, and when all the three detections pass, integrate each layer model and combine the key layer thickness and the reservoir enrichment degree to form a hydrate reservoir framework model.

7. The system of claim 6, wherein, The general framework generation module comprises: a key layer identification unit configured to identify key layers of the hydrate reservoir in the current area according to three-dimensional seismic data of the area to be studied; a key layer position correction unit configured to divide the formation layer position of a straight well in the current area by using the core experiment data and the logging and well logging data, and correct the position of each key layer based on the seismic interpretation by using the layer position division result; A key horizon integration unit configured to build key horizon maps of the hydrate reservoir and integrate them to form a general framework of the hydrate reservoir. A key horizon integration unit configured to build key horizon maps of the hydrate reservoir and integrate them to form a general framework of the hydrate reservoir.

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