A method and system for determining micro-geological features of a tight gas reservoir

Abstract

The application discloses a kind of microcosmic geologic feature determination method and system of tight gas reservoir in the technical field of oil and gas development, including historical data storage module, data acquisition module, data processing module and display module;Through historical data storage module, obtain the historical reservoir classification set about tight gas reservoir;Data processing module obtains the first marking range of geological extrusion position relationship in topographic model, judges whether the first marking range is located between adjacent drilling points Comparative area, to generate pore test instruction and sampling instruction Real-time microcosmic pore structure of drilling point is collected, to reduce overall data processing amount, then through real-time microcosmic pore structure verification, through the relativity of pore structure and geological parameter, quickly determine representative pore structure parameter.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil and gas development, and particularly relates to a micro geological feature determination method and system for a tight gas reservoir. BACKGROUND

[0002] Due to the increasing exhaustion of conventional oil and gas, tight oil and gas has become a key field of oil and gas exploration and development at home and abroad, wherein the pore structure of a tight gas reservoir not only controls the reservoir percolation characteristics, but also directly affects the production and ultimate recovery of the tight gas well, so how to identify and determine the pore structure of the tight gas reservoir is particularly important.

[0003] Due to the synergistic control of deposition, diagenesis and structure and the like in different stages of formation and evolution of the tight gas reservoir, the tight gas reservoir has strong spatial distribution heterogeneity, and how to predict the effective reservoir according to the pore structure influencing factors is of great significance.

[0004] At present, the analysis and test means such as high-pressure mercury injection, constant-speed mercury injection, nuclear magnetic resonance, gas-water phase permeability, gas-water two-phase displacement experiment and low-permeability rock start-up pressure gradient experiment bring accurate experimental parameters for evaluating the tight gas reservoir, but in the actual production process, due to the heterogeneity of the tight gas reservoir, the tight gas reservoirs with little difference exist in the determination of the effective reservoir, so it is necessary to quickly screen the multi-parameters according to the characteristics of the tight gas reservoir to determine the representative pore structure parameters. SUMMARY

[0005] The application aims to provide a micro geological feature determination method and system for a tight gas reservoir, which quickly determines the representative pore structure parameters based on the correlation between the pore structure and the geological parameters.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the application is as follows:

[0007] A micro geological feature determination system for a tight gas reservoir comprises a historical data storage module, a data acquisition module, a data processing module and a display module.

[0008] The historical data storage module is used for inputting and storing a historical reservoir classification set about the tight gas reservoir, and the historical reservoir classification set comprises reservoir evaluation features, associated features and pore structure classification types corresponding to each contrast reservoir; the reservoir evaluation features comprise contrast sand body structure, contrast micro pore structure, contrast percolation characteristics and contrast rock mechanics characteristics.

[0009] The correlation features include a forming reservoir relationship between the contrast micro-pore structure and the contrast reservoir sand body structure and the contrast rock mechanics features, a stratum extrusion position relationship and a geological extrusion schematic diagram between the contrast reservoir sand body structure and the contrast rock mechanics features, and a pore-permeability corresponding relationship between the contrast micro-pore structure and the contrast percolation features; the pore structure classification type is determined based on the forming reservoir relationship and the correlation features; the historical data storage module is in communication connection with the data acquisition module and the data processing module;

[0010] The data acquisition module is configured to identify and acquire the real-time micro-pore structure and the percolation features of each drilling point sample, and the reservoir sand body structure and the rock mechanics features corresponding to the drilling point, and send the real-time micro-pore structure, the percolation features, the reservoir sand body structure and the rock mechanics features to the historical data storage module and the data processing module;

[0011] The data processing module is configured to input a topographic model and drilling point samples, the topographic model including drilling points, reservoir sand body structures and rock mechanics features corresponding to each drilling point, and geological extrusion position relationships and geological extrusion schematic diagrams corresponding to the reservoir sand body structures and the rock mechanics features; the data processing module further acquires corresponding forming reservoir relationships based on the reservoir sand body structures and the rock mechanics features corresponding to the drilling points, takes the contrast micro-pore structure corresponding to the forming reservoir relationships as the to-be-output pore structure, and generates a pore verification instruction based on the forming reservoir relationships;

[0012] The data processing module acquires a first marking range of the geological extrusion position relationship in the topographic model based on the pore verification instruction, judges whether the first marking range in the topographic model is located in a contrast area between adjacent drilling points, sends a pore inspection instruction to the data acquisition module if the first marking range is located in the contrast area, and sends a spot-checking instruction to the data acquisition module if the first marking range is not located in the contrast area; the data acquisition module acquires the real-time micro-pore structure of the drilling point sample based on the pore inspection instruction in real time, and acquires the real-time micro-pore structure of the drilling point sample at intervals based on the spot-checking instruction;

[0013] The data processing module further compares the real-time micro-pore structure collected by the data acquisition module with the contrast micro-pore structure based on the pore inspection instruction or the spot-checking instruction; if the contrast micro-pore structure is similar to the real-time micro-pore structure, the topographic model is marked with a to-be-output pore structure based on the position of the drilling point; if the contrast micro-pore structure is not similar to the real-time micro-pore structure, the topographic model is marked with an abnormality based on the position of the drilling point;

[0014] The display module is configured to display each drilling point differently based on the to-be-output pore structure mark and the abnormality mark.

[0015] The above scheme has the following beneficial effects:

[0016] The management features are established by different parameters to output or verify the micro-pore structures of different drilling points, so as to improve the processing efficiency of the micro-pore structures.

[0017] Due to the different reservoir sand body structures or rock mechanical characteristics of different levels, the formation extrusion position relationship of different formations will change differently. By identifying and distinguishing the formation extrusion position relationship, the accuracy of subsequent verification of the micro-pore structure and effective reservoir is improved. Then, by different sampling, the drilling point samples are obtained, so as to reduce the processing amount of the real-time micro-pore structure corresponding to the drilling point samples, and verify the existing associated comparative micro-pore structure to add different markers for confirmation.

[0018] Further, the data processing module is further configured to calculate, based on the first marker range of the formation extrusion position relationship in the topographic model, a drilling number of the drilling points in the first marker range, compare the drilling number with a standard value, if the drilling number is greater than the standard value, add a data collection complete instruction to the topographic model based on the first marker range, and if the drilling number is greater than the standard value, add a data supplement instruction to the topographic model based on the first marker range.

[0019] Beneficial effects: By determining the important geological deformation position, the representative geological feature parameters can be more accurately obtained for comparison. At the same time, by adding the data collection complete instruction or the data supplement instruction to the topographic model according to the drilling number, whether the data in the first marker range is complete is determined, so as to ensure that the subsequent experimental analysis verifies the reservoir geological features of the region.

[0020] Further, when the drilling number is greater than the standard value, the data processing module uniformly marks the first marker range in the topographic model, divides the center of the first marker range into four equal parts, obtains the distribution number of each drilling point in the four equal parts, calculates the difference between the maximum value and the minimum value of the distribution number, compares the difference with a rated value, if the difference is greater than the rated value, adds a data supplement instruction to the topographic model based on the first marker range, and if the difference is less than the rated value, adds a data collection complete instruction to the topographic model based on the first marker range.

[0021] Beneficial effects: By determining the distribution of the drilling points in the first marker range, the uniformity of data collection is ensured, which provides a reference for subsequent geological feature verification.

[0022] Further, the comparative micro-pore structure includes pore radius characteristics and capillary pressure curve characteristics. The pore radius characteristics are determined based on high-pressure mercury injection experiment, and the capillary pressure curve characteristics are determined based on flow zone indicator FZI. The percolation characteristics are determined based on constant-speed mercury injection experiment.

[0023] Beneficial effects: By evaluating the capillary pressure curve characteristics through the flow zone index FZI, the pore radius characteristics and percolation characteristics are determined based on the high pressure mercury injection experiment and the constant speed mercury injection experiment, so as to evaluate the reservoir pore structure from the macroscopic direction.

[0024] Further, the data processing module is also used to obtain the corresponding comparative reservoir sand body structure and the comparative rock mechanics characteristics of the geological extrusion position relationship based on the pore inspection instruction, and then generate the corresponding adaptive extraction depth to obtain the extraction point sample based on the comparative reservoir sand body structure and the comparative rock mechanics characteristics.

[0025] Beneficial effects: By selecting and obtaining the drilling point sample, the screening efficiency and accuracy of the drilling point sample are improved, so that the representative extraction point sample can be obtained more quickly for verification.

[0026] Further, the data processing module is also used to record the geological extrusion position relationship correlation determination mark to the historical reservoir classification set for updating when the data processing module compares the similarity of the real-time micro-pore structure and the comparative pore structure based on the pore inspection instruction or the sampling instruction.

[0027] Beneficial effects: Based on the sending of the pore inspection instruction and the sampling instruction, the correlation degree between the pore structure classification and the relationship and correlation characteristics of the formed reservoir is adjusted, the accuracy of the historical reservoir classification set is improved, and the subsequent identification accuracy based on the historical reservoir classification set is facilitated.

[0028] Further, the abnormal mark includes the position mark of the drilling point, and the inconsistent data between the real-time micro-pore structure and the comparative pore structure.

[0029] Beneficial effects: By displaying the abnormal mark, the reference for the reason of the abnormal occurrence is provided, so as to determine the reason for the change of the micro-pore structure.

[0030] Further, the display module is also used to display the geological extrusion schematic diagram based on the position of the geological extrusion position relationship in the topographic model.

[0031] Beneficial effects: By displaying the geological extrusion position relationship, the relationship between the geological extrusion position relationship and the drilling point is expressed, so as to determine the correlation between the geological extrusion position relationship and the micro-pore characteristics.

[0032] Further, a method for determining micro-geological features of a tight gas reservoir, according to the method of the system for determining micro-geological features of the tight gas reservoir, comprises the following steps: step one, establishing a historical reservoir classification set about the tight gas reservoir, determining the reservoir evaluation features, associated features and pore structure classification types corresponding to each contrasted reservoir;

[0033] Step two, establishing a topographic model, collecting the reservoir sand body structure and rock mechanics features of each drilling point position in the topographic model, obtaining the corresponding forming reservoir relationship based on the reservoir sand body structure and rock mechanics features corresponding to the drilling point, comparing the first marking range of the geological extrusion position relationship in the topographic model with the comparison area between adjacent drilling points, when the first marking range is located in the comparison area, obtaining the real-time micro-pore structure of the drilling point sample, when the first marking range is not located in the comparison area, obtaining the real-time micro-pore structure of the drilling point sample at intervals;

[0034] Step three, comparing the real-time micro-pore structure with the contrasted pore structure, if similar, adding a pore structure marking to be output to the topographic model based on the position of the drilling point, if not similar, adding an abnormal marking to the topographic model based on the position of the drilling point.

[0035] Beneficial effects: the determination through the historical reservoir classification set provides a basic reference for subsequent pore structure identification, and the establishment of the topographic model provides a reference for the layout sampling of the drilling points, so as to reduce the number of drilling point samples collected and the subsequent data processing amount, and provide a reference for subsequent real-time micro-pore structure verification.

[0036] Further, in step three, when the abnormal marking is added to the topographic model based on the position of the drilling point, the relationship between the flow zone indicator FZI is also established based on the seepage features, and the relationship between the pore radius features and the capillary pressure curve features is determined;

[0037] Wherein, the expression between porosity and permeability is:

[0038] Definition HC=Fsτ 2 Sgv 2 ,

[0039] Get

[0040] Wherein, K is the permeability; is the porosity; Fs is the shape coefficient; τ is the pore tortuosity; Sgv is the specific surface area of unit volume of particles; HC is the rock structure constant; FZI is the flow zone indicator.

[0041] Beneficial effect: since the capillary pressure curve shape feature can well indicate the micro-pore feature of the reservoir, but since the capillary pressure curve is a difficult-to-quantify shape description; only the core is subjected to the mercury injection experiment analysis to obtain the curve shape feature, the evaluation method of the micro-pore throat structure of the reservoir through the capillary pressure curve shape feature has great limitation in the actual process, therefore, the macroscopic porosity and permeability parameters are used for the analysis and evaluation of the reservoir pore structure. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The schematic diagram of the system for determining the micro-geological features of the tight gas reservoir according to the embodiment of the present application.

[0043] Figure 2 The judgment schematic diagram of the method for determining the micro-geological features of the tight gas reservoir according to the embodiment of the present application.

[0044] Figure 3 The flow schematic diagram of the method for determining the micro-geological features of the tight gas reservoir according to the embodiment of the present application.

[0045] Figure 4 The cementation percentage content graph of Zhidan-Ganquan He8-Benxi Formation according to the embodiment of the present application.

[0046] Figure 5 The porosity and permeability schematic diagram of the He8 reservoir in the research area according to the embodiment of the present application.

[0047] Figure 6 The porosity and permeability schematic diagram of the Shan1 reservoir in the research area according to the embodiment of the present application.

[0048] Figure 7 The porosity and permeability schematic diagram of the Shan2 reservoir in the research area according to the embodiment of the present application.

[0049] Figure 8 The porosity and permeability schematic diagram of the Benxi reservoir in the research area according to the embodiment of the present application.

[0050] Figure 9 The main throat type schematic diagram of the clastic rock reservoir according to the embodiment of the present application.

[0051] Figure 10 The reservoir throat type schematic diagram of the research area according to the embodiment of the present application.

[0052] Figure 11 The I type curve and its pore throat distribution and permeability contribution rate curve diagram according to the embodiment of the present application.

[0053] Figure 12 The II type curve and its pore throat distribution and permeability contribution rate curve diagram according to the embodiment of the present application.

[0054] Figure 13This is a diagram of the Class III curve and its pore throat distribution and permeability contribution rate in an embodiment of the present invention.

[0055] Figure 14 This is a diagram showing the Class IV curve and its pore throat distribution versus permeability contribution rate in an embodiment of the present invention.

[0056] Figure 15 This is a characteristic diagram of the mercury pressure curve in box 8 of the present invention.

[0057] Figure 16 This is a characteristic diagram of the mercury intrusion curve of reservoir 1 in embodiment of the present invention.

[0058] Figure 17 This is a characteristic diagram of the mercury intrusion curve of reservoir Shan 2 according to an embodiment of the present invention.

[0059] Figure 18 This is a characteristic diagram of the mercury intrusion curve of the Benxi reservoir according to an embodiment of the present invention.

[0060] Figure 19 This is a distribution diagram of reservoir permeability contribution values ​​in an embodiment of the present invention. Detailed Implementation

[0061] The following detailed description illustrates the specific implementation method:

[0062] The basic implementation examples are as follows: Figures 1 to 3 As shown: A system for determining the microscopic geological characteristics of tight gas reservoirs, including a historical data storage module, a data acquisition module, a data processing module, and a display module.

[0063] The historical data storage module is used to input and store historical reservoir classification sets for tight gas reservoirs. These sets include reservoir evaluation characteristics, correlation characteristics, and pore structure classification types for each comparative reservoir. Reservoir evaluation characteristics include comparative reservoir sand body structure, comparative micropore structure, comparative seepage characteristics, and comparative rock mechanical characteristics. Correlation characteristics include the formation reservoir relationship between comparative micropore structure and comparative reservoir sand body structure and comparative rock mechanical characteristics; the formation compression location relationship and geological compression diagram between comparative reservoir sand body structure and comparative rock mechanical characteristics; and the porosity-permeability correspondence between comparative micropore structure and comparative seepage characteristics. The pore structure classification type is determined based on the formation reservoir relationship and correlation characteristics. The historical data storage module is communicatively connected to the data acquisition module and the data processing module.

[0064] and the comparative micro-pore structure includes pore radius characteristics and capillary pressure curve characteristics, the pore radius characteristics are determined based on a high-pressure mercury injection experiment, and the capillary pressure curve characteristics are determined based on a flow zone indicator FZI; and the percolation characteristics are determined based on a constant-rate mercury injection experiment, and the high-pressure mercury injection experiment and the constant-rate mercury injection experiment both belong to the prior art and are well known to those skilled in the art, and thus will not be described herein.

[0065] For example, since the existing reservoir research is determined based on basic petrology characteristics, reservoir macro-features, reservoir micro-features and percolation characteristics, one of which cannot be used to completely and accurately evaluate the reservoir, the correlation between adjacent parameters is used to establish the correlation between adjacent positions, provide guidance for evaluation, and determine abnormal positions, so as to determine the micro-pore structure of different drilling points based on different parameters, and output or verify the micro-pore structure of different drilling points, thereby improving the processing efficiency of the micro-pore structure.

[0066] The data acquisition module is configured to identify and acquire real-time micro-pore structures and percolation characteristics of each drilling point sample, and reservoir sand body structures and rock mechanics characteristics corresponding to the drilling point, and send the real-time micro-pore structures, the percolation characteristics, the reservoir sand body structures and the rock mechanics characteristics to the historical data storage module and the data processing module.

[0067] The data processing module is configured to input a terrain model and a drilling point sample, the terrain model including drilling points, reservoir sand body structures and rock mechanics characteristics corresponding to each drilling point, and geological extrusion position relationships and a geological extrusion schematic diagram corresponding to the reservoir sand body structures and the rock mechanics characteristics; the data processing module is further configured to acquire corresponding shaped reservoir relationships based on the reservoir sand body structures and the rock mechanics characteristics corresponding to the drilling point, use comparative micro-pore structures corresponding to the shaped reservoir relationships as to-be-output pore structures, and generate pore verification instructions based on the shaped reservoir relationships. The data processing module is further configured to acquire comparative reservoir sand body structures and comparative rock mechanics characteristics corresponding to the geological extrusion position relationships based on the pore verification instructions, and acquire a sampling point sample based on the comparative reservoir sand body structures and the comparative rock mechanics characteristics.

[0068] For example, due to the differences in reservoir sand body structures or rock mechanics characteristics at different levels, the formation extrusion position relationships of different formations will change differently, and the formation extrusion position relationships are identified and distinguished to improve the accuracy of subsequent micro-pore structure and effective reservoir verification; and different sampling conditions are used to acquire drilling point samples to reduce the processing amount of drilling point samples corresponding to real-time micro-pore structures, and the existing related comparative micro-pore conditions are verified to add different markers for confirmation.

[0069] The data processing module obtains a first marking range of the geological extrusion position relationship in the topographic model based on the pore verification instruction, judges whether the first marking range in the topographic model is located in a comparison area between adjacent drilling points, if the first marking range is located in the comparison area, sends a pore inspection instruction to the data acquisition module, if the first marking range is not located in the comparison area, sends an inspection instruction to the data acquisition module; the data acquisition module obtains real-time micro-pore structures of drilling point samples based on the pore inspection instruction in real time, and obtains real-time micro-pore structures of drilling point samples at intervals based on the inspection instruction.

[0070] The data processing module is also used to calculate the number of drilling points in the first marking range based on the first marking range of the geological extrusion position relationship in the topographic model, compare the number of drilling with a set standard value, if the number of drilling is greater than the standard value, add a data acquisition complete instruction to the topographic model based on the first marking range, if the number of drilling is greater than the standard value, the data processing module uniformly marks the first marking range in the topographic model, divides the first marking range into four equal parts at the center of the first marking range, obtains the distribution number of each drilling point in the four equal parts, calculates the difference between the maximum value and the minimum value of the distribution number, compares the difference with a set rated value, if the difference is greater than the rated value, adds a data supplement instruction to the topographic model based on the first marking range, if the difference is less than the rated value, adds a data acquisition complete instruction to the topographic model based on the first marking range.

[0071] For example, during the arrangement of drilling points, the non-uniformity of drilling collection often leads to the incompleteness of data acquisition. By determining important geological deformation positions, more accurate representative geological feature parameters can be obtained for comparison. At the same time, the number of drilling points is used to add a data acquisition complete instruction or a data supplement instruction to the topographic model to determine whether the data in the first marking range is complete, so as to ensure that the subsequent experimental analysis can verify the reservoir geological characteristics of the region.

[0072] At the same time, by dividing the distribution and number of drilling points, the uniformity of the data acquisition process is determined, and the distribution of drilling points in the first marking range is determined to provide a reference for subsequent geological feature verification.

[0073] The data processing module compares the real-time micro-pore structure collected by the data acquisition module with the comparison pore structure based on the pore inspection instruction or the inspection instruction, if the comparison micro-pore structure is similar to the real-time micro-pore structure, adds a to-be-output pore structure mark to the topographic model based on the position of the drilling point, if the comparison micro-pore structure is not similar to the real-time micro-pore structure, adds an abnormal mark to the topographic model based on the position of the drilling point, and the abnormal mark includes the position mark of the drilling point, and the inconsistent data between the real-time micro-pore structure and the comparison pore structure.

[0074] For example, by establishing a historical reservoir classification set to determine the relationship between pore structure and geological parameters, due to the heterogeneous characteristics of tight gas reservoirs, it is easy to occur that the contrast micro-pore structure is inconsistent with the real-time micro-pore structure. By screening and processing the drilling points, the initial state of the drilling point sample is determined, the processing amount and the contrast amount of the subsequent drilling point sample are reduced, the first verification is carried out based on the geological extrusion position relationship, and the drilling point position is adjusted, so as to ensure that the pore structure parameters are representative. Finally, the accuracy is ensured by comparing the micro-pore structure and the real-time micro-pore structure, so as to quickly determine the representative pore structure parameters.

[0075] The display module is used for different marking display of each drilling point based on the to-be-output pore structure mark and the abnormal mark, and the geological extrusion schematic diagram is displayed based on the position of the geological extrusion position relationship in the topographic model.

[0076] In this embodiment, the exploration well of Zhidan-Ganquan research area is taken as an example, and the data in Table 1 and Table 2 are obtained based on historical data and actual drilling. As shown in Table 1, it is a rock type and detrital component statistical table. As shown in Table 2, it is a interstitial material component statistical table.

[0077] Table 1: Detrital component statistical table of He 8-Benxi Formation in Zhidan-Ganquan area (%)

[0078]

[0079]

[0080] Table 2: Interstitial material component statistical table of He 8-Benxi Formation in Zhidan-Ganquan area (%)

[0081]

[0082] As shown in Table 1, by using the triangular diagram method, the sandstone of He 8-Benxi Formation in the research area mainly has three types: quartz sandstone, lithic quartz sandstone and lithic sandstone. The detrital component is mainly quartz, with an average of 75.92%, followed by lithic, with an average of 23.22%, and the content of feldspar is relatively small, with an average of only 0.86%. Combined with the actual distribution, it can be known that the Benxi reservoir is mainly quartz sandstone and lithic quartz sandstone, and a small amount of lithic sandstone, with an average of 91.8% of quartz content, 8.03% of lithic content and 0.17% of feldspar content. Among the lithic components, the metamorphic rock content is the highest, but it is greatly reduced compared with the He 8, Shan 1 and Shan 2 reservoirs, with an average of 6.69%, followed by the argillaceous detritus, with an average of 2.4%, a small amount of calcareous detritus, chlorite and mica, and almost no sedimentary rock detritus.

[0083] From Table 2, it can be seen that the content of interstitial material in the He 8- Benxi Formation reservoir in the study area is not high, but the range of variation is large, the highest content is 65%, the lowest content is only 3%, and the average content is 11.17%, among which the content of cement is much greater than that of miscellaneous base, and the miscellaneous base is mainly argillaceous iron. The interstitial materials commonly existing in each target layer are kaolinite, hydromica, chlorite, and silica, and the ankerite, siderite, and iron calcite are well developed in some wells, while the tuffaceous, magnetite, and white titanium ore cement only exist in some layers of individual wells and are not universal.

[0084] At the same time, the main particle size interval of the Benxi reservoir is in the range of 0.1-1.0 mm, and the medium-coarse grain structure is dominant. The particle sorting is mainly medium-poor, and a small amount is well sorted; the roundness is mainly sub-edge, followed by sub-circular and circular; the particle support is mainly convex-concave contact and linear contact, a small number of point contact, point-linear contact and linear-convex-concave contact, and occasionally suture line contact; the cementation type is mainly pore cementation, followed by pore-rejuvenation cementation, a small amount of film cementation and matrix cementation, and no pressure-embedded cementation. Quartz secondary enlargement is common (as shown in Figure 4 ).

[0085] Based on the above analysis of rock type, detrital component, interstitial material component and cementation characteristics, the mechanical compaction, chemical pressure solution, cementation, metasomasis and dissolution and other diagenetic processes and complex diagenetic evolution in the geological process are deduced to determine and establish the reservoir sand body structure and rock mechanics characteristics, and to determine the correlation between the reservoir sand body structure and the rock mechanics characteristics and the strata extrusion position relationship and the geological extrusion diagram.

[0086] At the same time, the physical property distribution characteristics of the reservoir area are obtained, and the physical property analysis data of more than 4600 core samples of 54 wells in the study area are obtained. The distribution characteristics of the reservoir physical properties are statistically classified. The statistical results show that the reservoir porosity is mainly between 2.0% and 13.0%, and the permeability is between 0.01 and 3.0 x 10 -3 μm 2 . The porosity and permeability of most samples are biased towards the low value side, the porosity is generally less than 10.0%, and the permeability is generally less than 1.0 x 10 -3 μm 2 , belonging to low porosity, low permeability and ultra-low permeability tight reservoir. The change of permeability is mainly controlled by the development degree of pore and its spatial configuration relationship, and the permeability and porosity are positively correlated, and the correlation is good. The correlation coefficients of He 8, Shan 1, Shan 2 and Benxi reservoirs in the study area are 0.5699, 0.5153, 05966 and 0.3935 respectively, among which the correlation of the porosity and permeability of the Benxi Formation is the worst, and the influencing factors are the most complex (as shown in Figures 5 to 8 ).

[0087] The analysis shows that the He 8-Benxi Formation in the study area mainly develops four types of pores, i.e. primary intergranular pores, secondary solution pores, intercrystalline pores and microfractures. Among them, the secondary solution pores and intercrystalline pores are dominant, and the primary intergranular pores are in a secondary position in the pore composition. The intergranular pores are the pores remaining after the compaction and filling cementation of the granular pores, and have triangular, polygonal, irregular and other shapes. The secondary solution pores are mainly detrital and feldspar solution pores and matrix solution pores. According to the contact type and cementation type of the detrital particles, the throat can be divided into four types: necking throat, point throat, sheet or curved sheet throat and pipe bundle throat (as shown in Figure 9 According to the cast thin section and scanning electron microscope analysis of the study area and adjacent areas, the throat types of the target layer in the study area mainly include sheet throat, point throat and pipe bundle throat (as shown in Figure 10

[0088] Based on the existing four types of capillary pressure curve classification, the pore-throat corresponding relationship between the micro-pore structure and the percolation characteristics in the study area is determined (as shown in Figures 11 to 14 According to the capillary pressure data (as shown in Figures 15-18 The permeability contribution value of different pore-throat of each type of reservoir is calculated, and Table 3 is obtained.

[0089] Table 3 Classification and statistical table of pore structure characteristic parameters of capillary pressure curve of reservoir in the study area

[0090]

[0091] The permeability cumulative contribution value of different pore-throat volume reflects the pore-throat contribution ability of the reservoir. The lower limit of the pore-throat of the He 8-Benxi Formation in the Zhidan-Ganquan area is described according to the characteristics of the permeability cumulative contribution value of the pore-throat volume, so as to analyze the reservoir storage and percolation ability with the effective pore-throat lower limit, and to comprehensively analyze and establish Table 3 (Classification and statistical table of pore structure characteristic parameters of capillary pressure curve of reservoir in the study area). Based on Figure 19 Quantitative analysis of the contribution ability of the pore volume controlled by different pore-throat radii to the permeability, and then the reference basis for the determination of the correlation characteristics is improved.

[0092] A method for determining the micro-geological characteristics of a tight gas reservoir, comprising the following steps: step one, establishing a historical reservoir classification set about the tight gas reservoir, and determining the reservoir evaluation characteristics, correlation characteristics and pore structure classification type corresponding to each compared reservoir.

[0093] ​Step two, establish a topographic model, collect the reservoir sand body structure and rock mechanics characteristics of each drilling point position in the topographic model, obtain the corresponding forming reservoir relationship based on the corresponding reservoir sand body structure and rock mechanics characteristics of the drilling point, and compare the comparison area between the first mark range of the geological extrusion position relationship in the topographic model and the adjacent drilling point. When the first mark range is located in the comparison area, the real-time micro-pore structure of the drilling point sample is obtained, and when the first mark range is not located in the comparison area, the real-time micro-pore structure of the drilling point sample is obtained.

[0094] Step three, similarity comparison of real-time micro-pore structure and comparison pore structure, if similar, add the pore structure mark to be output to the topographic model based on the position of the drilling point, if not similar, add an abnormal mark to the topographic model based on the position of the drilling point.

[0095] The micro-geological feature determination method is a supplementary description of the above-mentioned embodiments, and has the same principle and effect. This embodiment will not be described again.

[0096] Since the morphological characteristics of the capillary pressure curve can well indicate the micro-pore characteristics of the reservoir, but since the capillary pressure curve is a difficult-to-quantify morphological description, only by performing mercury injection experiment analysis on the core can the morphological characteristics of the curve be obtained, and the evaluation method of the micro-pore throat structure of the reservoir through the morphological characteristics of the capillary pressure curve has great limitations in the actual process, therefore, the macroscopic porosity and permeability parameters are used to analyze and evaluate the reservoir pore structure. Therefore, when the abnormal mark is added to the topographic model based on the position of the drilling point, the relationship between the flow zone index FZI is established based on the percolation characteristics, and the relationship between the pore radius characteristics and the capillary pressure curve characteristics is determined.

[0097] Wherein, the expression between porosity and permeability is:

[0098] Define HC = Fsτ 2 Sgv 2 ,

[0099] Get

[0100] Wherein, K is the permeability; is the porosity; Fs is the shape coefficient; τ is the pore tortuosity; Sgv is the specific surface area of unit volume of particles; HC is the rock structure constant; FZI is the flow zone index.

[0101] In another embodiment, the data processing module is further configured to, when the data processing module compares the real-time micro-pore structure collected by the data collection module with the contrast micro-pore structure based on the pore inspection instruction or the sampling instruction, if the contrast micro-pore structure is similar to the real-time micro-pore structure, record a geological extrusion position relationship correlation determination mark to the historical reservoir classification set for updating; if the contrast micro-pore structure is not similar to the real-time micro-pore structure, record a geological extrusion position relationship irrelevance mark to the historical reservoir classification set for updating.

[0102] For example, during the real-time micro-pore structure comparison process, due to the influence of different degrees of correlation, the accuracy of the historical reservoir classification set verification is reduced, and the sending of the pore inspection instruction and the sampling instruction is used to adjust the correlation degree between the pore structure classification and the correlation characteristics of the formed reservoir relationship, so as to improve the accuracy of the historical reservoir classification set, and facilitate the subsequent identification accuracy based on the historical reservoir classification set.

[0103] The above is only an embodiment of the present application, and the common knowledge of specific structures and / or characteristics in the scheme is not described in detail. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be regarded as the protection scope of the present application, which will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.

Claims

1. A system for determining microgeologic features of a tight gas reservoir, the system comprising: The system comprises a historical data storage module, a data acquisition module, a data processing module and a display module. The historical data storage module is configured to record and store a historical reservoir classification set of the tight gas reservoir, the historical reservoir classification set comprising reservoir evaluation features, correlation features and pore structure classification types corresponding to each contrast reservoir, and the reservoir evaluation features comprising contrast reservoir sand body structure, contrast microscopic pore structure, contrast seepage characteristics and contrast rock mechanics characteristics. The contrast microscopic pore structure comprises pore radius features and capillary pressure curve features, the pore radius features being determined based on high-pressure mercury injection experiments, and the capillary pressure curve features being determined based on flow zone indicators FZI; and the seepage characteristics are determined based on constant-rate mercury injection experiments. The data processing module is configured to establish a correlation between the flow zone indicators FZI based on the seepage characteristics, and determine a correlation between the pore radius features and the capillary pressure curve features. wherein the expression between porosity and permeability is: ; Definition HC = 0 FZI = 0 ; obtained ; Wherein, K is permeability; is porosity; Fs is shape factor; ; ; FZI is flow zone index; The correlation features comprise a shaped reservoir relationship between the contrast microscopic pore structure and the contrast reservoir sand body structure and the contrast rock mechanics characteristics, a stratum extrusion position relationship and a geological extrusion schematic diagram between the contrast reservoir sand body structure and the contrast rock mechanics characteristics, and a pore-permeability corresponding relationship between the contrast microscopic pore structure and the contrast seepage characteristics; the pore structure classification types are determined based on the shaped reservoir relationship and the correlation features; and the historical data storage module is in communication connection with the data acquisition module and the data processing module. The data acquisition module is configured to identify and acquire real-time microscopic pore structures and seepage characteristics of each drilling point sample, and reservoir sand body structure and rock mechanics characteristics corresponding to the drilling point, and send the real-time microscopic pore structures, the seepage characteristics, the reservoir sand body structure and the rock mechanics characteristics to the historical data storage module and the data processing module. The data processing module is configured to record a topographic model and a drilling point sample, the topographic model comprising drilling points, reservoir sand body structure and rock mechanics characteristics corresponding to each drilling point, and a geological extrusion position relationship and a geological extrusion schematic diagram corresponding to the reservoir sand body structure and the rock mechanics characteristics; and the data processing module is further configured to acquire a corresponding shaped reservoir relationship based on the reservoir sand body structure and the rock mechanics characteristics corresponding to the drilling point, take contrast microscopic pore structure corresponding to the shaped reservoir relationship as a to-be-output pore structure, and generate a pore verification instruction based on the shaped reservoir relationship. The data processing module is configured to acquire a first marking range of the geological extrusion position relationship in the topographic model based on the pore verification instruction, judge whether the first marking range in the topographic model is located in a contrast area between adjacent drilling points, send a pore inspection instruction to the data acquisition module if the first marking range is located in the contrast area, and send a spot-checking instruction to the data acquisition module if the first marking range is not located in the contrast area; and the data acquisition module is configured to acquire real-time microscopic pore structures of the drilling point sample based on the pore inspection instruction, and acquire real-time microscopic pore structures of the drilling point sample at intervals based on the spot-checking instruction. The data processing module compares the real-time micro-pore structure collected by the data collection module with the contrast pore structure based on the pore inspection instruction or the sampling instruction. If the contrast micro-pore structure is similar to the real-time micro-pore structure, the data processing module adds a to-be-output pore structure mark to the topographic model based on the position of the drilling point. If the contrast micro-pore structure is not similar to the real-time micro-pore structure, the data processing module adds an abnormal mark to the topographic model based on the position of the drilling point. The display module displays the drilling points based on the to-be-output pore structure mark and the abnormal mark.

2. The system for determining micro-geological characteristics of a tight gas reservoir of claim 1, wherein: The data processing module calculates the number of drilling points in the first mark range in the topographic model based on the position relationship of the geological extrusion, compares the number of drilling points with a standard value, and adds a data collection completion instruction to the topographic model based on the first mark range if the number of drilling points is greater than the standard value. If the number of drilling points is greater than the standard value, the data processing module adds a data supplement instruction to the topographic model based on the first mark range.

3. The system for determining micro-geological characteristics of a tight gas reservoir of claim 2, wherein: The data processing module uniformly marks the first mark range in the topographic model when the number of drilling points is greater than the standard value, divides the first mark range into four equal parts at the center of the first mark range, obtains the distribution number of each drilling point in the four equal parts, calculates the difference between the maximum value and the minimum value of the distribution number, compares the difference with a rated value, and adds a data supplement instruction to the topographic model based on the first mark range if the difference is greater than the rated value. If the difference is less than the rated value, the data processing module adds a data collection completion instruction to the topographic model based on the first mark range.

4. The system for determining micro-geological characteristics of a tight gas reservoir of claim 3, wherein: The data processing module obtains the contrast reservoir sand body structure and the contrast rock mechanics characteristics corresponding to the position relationship of the geological extrusion based on the pore inspection instruction, and generates a corresponding adaptive collection depth based on the contrast reservoir sand body structure and the contrast rock mechanics characteristics to obtain the sampling point sample.

5. The system for determining micro-geological characteristics of a tight gas reservoir of claim 4, wherein: When the data processing module compares the real-time micro-pore structure collected by the data collection module with the contrast pore structure based on the pore inspection instruction or the sampling instruction, if the contrast micro-pore structure is similar to the real-time micro-pore structure, the data processing module records a geological extrusion position relationship association determination mark to update the historical reservoir classification set. If the contrast micro-pore structure is not similar to the real-time micro-pore structure, the data processing module records a geological extrusion position relationship irrelevant mark to update the historical reservoir classification set.

6. The system for determining micro-geological characteristics of a tight gas reservoir of claim 5, wherein: The abnormal mark includes the position mark of the drilling point and the inconsistent data between the real-time micro-pore structure and the contrast pore structure.

7. The system for determining micro-geological characteristics of a tight gas reservoir of claim 6, wherein: The display module displays a geological extrusion schematic diagram based on the position of the geological extrusion in the topographic model.

8. A method of determining microgeological features of a tight gas reservoir, characterized by, The method for determining the micro-geological characteristics of a tight gas reservoir according to any one of claims 1-7 comprises the following steps: step one, establishing a historical reservoir classification set for the tight gas reservoir, and determining the reservoir evaluation characteristics, the associated characteristics, and the pore structure classification type corresponding to each contrast reservoir; Step two, establish a topographic model, collect the reservoir sand body structure and rock mechanics characteristics of each drilling point position in the topographic model, obtain the corresponding forming reservoir relationship based on the corresponding reservoir sand body structure and rock mechanics characteristics of the drilling point, and compare the comparison area between the first mark range of the geological extrusion position relationship in the topographic model and the adjacent drilling point, when the first mark range is located in the comparison area, obtain the real-time micro-pore structure of the drilling point sample, when the first mark range is not located in the comparison area, interval obtain the real-time micro-pore structure of the drilling point sample; Step three, compare the similarity of the real-time micro-pore structure and the comparison pore structure, if similar, add the to-be-output pore structure mark to the topographic model based on the position of the drilling point, if not similar, add the abnormal mark to the topographic model based on the position of the drilling point.

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