A method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework

Abstract

The application discloses a method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework, and relates to the technical field of oil logging, which comprises the following steps: determining a first sequence interface set based on logging curve characteristics, and determining a second sequence interface set based on well seismic information and logging information; determining a target sequence interface set in the first sequence interface set and the second sequence interface set, and determining an isochronous stratigraphic framework by using the target sequence interface set; determining rock-electricity parameters and formation water resistivity based on core data and a preset Archie formula, and calculating porosity based on the determined target porosity evaluation model; determining oil saturation of each sequence in the isochronous stratigraphic framework based on the rock-electricity parameters, the formation water resistivity, the porosity and the preset Archie formula, and performing reservoir unit correlation based on logging curves, so as to identify oil and gas layers in each sequence by using the obtained correlation results, the porosity and the oil saturation. The application improves the reliability of oil and gas layer identification.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil well logging, and particularly relates to a method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework. BACKGROUND

[0002] In the process of oil and gas exploration and development, reservoir correlation is a key prerequisite for accurately identifying oil and gas layers.

[0003] Currently, well logging technicians use lithostratigraphic correlation method in reservoir evaluation. That is, according to the principle of "mudstone to mudstone, sandstone to sandstone", oil and gas layers are identified by using the established oil and gas layer identification criteria based on the changes of well logging curves such as resistivity and porosity between wells, and referring to the test results, according to the similar geophysical well logging response characteristics of specific lithostratigraphy in the same stratigraphic system. However, this method has many defects. First, the well logging curve shapes of different strata may be similar, which can easily lead to stratigraphic correlation errors. Second, well logging data can only reflect part of the stratigraphic information, and for complex strata, the similarity of well logging curves is poor, making it difficult to achieve accurate correlation. Third, when the strata change suddenly, the well logging curves will be abnormal, which seriously affects the accuracy of stratigraphic correlation. As a result, the same small layer between wells under lithostratigraphic correlation is not in the same sedimentary environment, and the formation water resistivity and litho-electric parameters are different, so the oil and gas saturation calculated accordingly lacks comparability between wells, and the measured resistivity, porosity and other well logging curves also have no horizontal correlation significance, which makes it difficult to meet the needs of efficient oil and gas exploration and development.

[0004] Therefore, how to improve the accuracy and efficiency of oil and gas layer identification is a problem to be solved at present. SUMMARY

[0005] Therefore, the present application aims to provide a method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework, which can improve the accuracy and efficiency of oil and gas layer identification. The specific scheme is as follows:

[0006] In the first aspect, the present application provides a method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework, which comprises:

[0007] In the target oil and gas exploration area, a first set of sequence boundaries is determined based on well logging curve characteristics, and a second set of sequence boundaries is determined based on well seismic information and well logging information;

[0008] A target set of sequence boundaries is determined in the first set of sequence boundaries and the second set of sequence boundaries based on a preset interface determination rule, and an isochronous stratigraphic framework is determined using the target set of sequence boundaries, so as to calibrate sequences in the isochronous stratigraphic framework;

[0009] Determine rock-electricity parameters and formation water resistivity of each sequence based on core data and a preset Archie formula, and determine a target porosity evaluation model of each sequence based on three porosity logging curve information and the core data, so as to determine porosity of the sequence by using the target porosity evaluation model.

[0010] Determine oil saturation of each sequence based on the rock-electricity parameters, the formation water resistivity, the porosity and the preset Archie formula, and perform reservoir unit correlation based on logging curves, so as to identify oil and gas layers in each sequence by using the obtained correlation results, the porosity and the oil saturation.

[0011] Optionally, the determining the first sequence boundary set based on logging curve characteristics comprises:

[0012] Take a well containing drilling core information and logging information as a key well, and modify the logging information by using core data, so as to construct a standard profile of the key well based on the modified logging information.

[0013] In the standard profile, determine a first sequence boundary set based on logging curve characteristics in the logging information.

[0014] Optionally, the determining the second sequence boundary set based on well-side seismic information and logging information comprises:

[0015] Determine a seismic synthetic record based on sonic curve and density curve in the logging information, and modify the seismic synthetic record according to well-side seismic information, so as to obtain the seismic synthetic record satisfying a preset similarity condition.

[0016] Construct a seismic profile of the key well based on the modified logging information, and determine a second sequence boundary set in the seismic profile by using the seismic synthetic record satisfying the preset similarity condition.

[0017] Optionally, the determining rock-electricity parameters and formation water resistivity of each sequence based on core data and a preset Archie formula comprises:

[0018] Obtain formation factors, porosity data, resistivity increase coefficients, water saturation and formation water information in the core data.

[0019] Determine rock-electricity parameters of each sequence based on a preset Archie formula, the formation factors, the porosity data, the resistivity increase coefficients and the water saturation.

[0020] convert the ion mineralization degree into equivalent NaCl mineralization degree based on an equivalent coefficient of the ion mineralization degree in the formation water information, and determine the formation water resistivity under the experimental test condition by using the equivalent NaCl mineralization degree;

[0021] determine the formation water resistivity under the formation condition based on a preset conversion formula and the formation water resistivity under the experimental test condition.

[0022] Optionally, the determining the target porosity evaluation model of each of the sequences based on the three porosity logging curve information and the core data comprises:

[0023] modifying the depth information in the core data according to the depth information in the logging information to obtain target depth information in which the depth information of the core data is consistent with the depth information in the logging information;

[0024] obtaining the three porosity logging curve information of the corresponding depth based on the target depth information, and respectively determining the relationship information among the acoustic wave, the density and the neutron in the porosity data and the three porosity logging curve information;

[0025] converting the relationship information into a relationship curve, and performing single-term fitting or multi-term fitting by using the relationship curve and the porosity data to obtain each porosity evaluation model;

[0026] determining, in each of the porosity evaluation models, a porosity evaluation model that meets a preset correlation condition as a target porosity evaluation model.

[0027] Optionally, the reservoir unit comparison based on the logging curve comprises:

[0028] determining a logging curve that meets a preset sensitivity condition in the logging information as a comparison curve, and performing reservoir unit comparison between the tested well and the to-be-tested well based on the comparison curve to obtain a comparison result.

[0029] Optionally, the identifying the oil and gas layer in each of the sequences by using the obtained comparison result, the porosity and the oil saturation comprises:

[0030] obtaining the reservoir unit lithology and the curve change information in the obtained comparison result;

[0031] determining the reservoir type of each of the sequences based on the reservoir unit lithology, the curve change information, the porosity and the oil saturation, so as to determine the oil and gas layer in each of the sequences by using the reservoir type.

[0032] In a second aspect, the present application provides a device for identifying an oil and gas layer based on isochronous formation framework formation fine comparison, comprising:

[0033] an interface determining module, configured to determine a first set of sequence interfaces based on characteristics of well logging curves in a target oil and gas exploration area, and determine a second set of sequence interfaces based on seismic information and well logging information;

[0034] a framework determining module, configured to determine a target set of sequence interfaces from the first set of sequence interfaces and the second set of sequence interfaces based on preset interface determination rules, and determine an isochronous stratigraphic framework by using the target set of sequence interfaces, so as to calibrate sequences in the isochronous stratigraphic framework;

[0035] a porosity determining module, configured to determine rock-electricity parameters and formation water resistivity of each sequence based on core data and a preset Archie formula in the isochronous stratigraphic framework, and determine a target porosity evaluation model of each sequence based on three porosity logging curve information and the core data, so as to determine porosity of the sequence by using the target porosity evaluation model;

[0036] an oil and gas layer identifying module, configured to determine oil saturation of each sequence based on the rock-electricity parameters, the formation water resistivity, the porosity and the preset Archie formula, and perform reservoir unit correlation based on well logging curves, so as to identify oil and gas layers in each sequence by using obtained correlation results, the porosity and the oil saturation.

[0037] In a third aspect, the present application provides an electronic device, comprising:

[0038] a memory, configured to save a computer program;

[0039] a processor, configured to execute the computer program to implement the oil and gas layer identifying method based on isochronous stratigraphic framework stratigraphic fine correlation.

[0040] In a fourth aspect, the present application provides a computer readable storage medium, configured to save a computer program; wherein the computer program is executed by a processor to implement the oil and gas layer identifying method based on isochronous stratigraphic framework stratigraphic fine correlation.

[0041] In the present application, in a target oil and gas exploration area, a first sequence interface set is determined based on logging curve characteristics, and a second sequence interface set is determined based on well seismic information and logging information; a target sequence interface set is determined in the first sequence interface set and the second sequence interface set based on a preset interface determination rule, and an isochronous stratigraphic framework is determined using the target sequence interface set to calibrate sequences in the isochronous stratigraphic framework; under the isochronous stratigraphic framework, rock-electricity parameters and formation water resistivity of each sequence are determined based on core data and a preset Archie formula, and a target porosity evaluation model of each sequence is determined based on three porosity logging curve information and the core data to determine the porosity of the sequence using the target porosity evaluation model; oil saturation of each sequence is determined based on the rock-electricity parameters, the formation water resistivity, the porosity and the preset Archie formula, and reservoir unit correlation is carried out based on logging curves to identify oil and gas layers in each sequence using the obtained correlation results, the porosity and the oil saturation. As can be seen from the above, the present application first obtains a first sequence interface set according to logging curve characteristics, and a second sequence interface set according to well seismic information and logging information. A target sequence interface set is determined in the two sets according to a preset rule, and an isochronous stratigraphic framework is constructed and sequences are calibrated according to the target sequence interface set. Under the stratigraphic framework, rock-electricity parameters and formation water resistivity of the sequences are determined based on core data and a preset Archie formula, a target porosity evaluation model is determined based on three porosity logging curve information and core data to calculate the porosity. Oil saturation is calculated based on rock-electricity parameters, formation water resistivity, porosity and a preset Archie formula, reservoir unit correlation is carried out based on logging curves, and oil and gas layers in each sequence are identified based on correlation results, porosity and oil saturation. In this way, the present application can improve the accuracy and efficiency of oil and gas layer identification, thereby improving the user experience. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on the provided drawings.

[0043] Figure 1 A flow chart of a method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework disclosed by the present application;

[0044] Figure 2 A schematic diagram of an isochronous stratigraphic framework in a target oil and gas exploration area disclosed by the present application;

[0045] Figure 3 A schematic diagram of the relationship between stratigraphic factors and porosity disclosed by the present application;

[0046] Figure 4 A schematic diagram of the relationship between the resistance increase coefficient and the water saturation disclosed in the present application;

[0047] Figure 5 A schematic diagram of the relationship between the SH5 medium density, acoustic wave, neutron and porosity data disclosed in the present application;

[0048] Figure 6 A schematic diagram of the comprehensive results of X1 well disclosed in the present application;

[0049] Figure 7 A schematic diagram of the comprehensive results of X2 well disclosed in the present application;

[0050] Figure 8 A schematic diagram of the comprehensive results of X3 well (left) - X4 well (right) disclosed in the present application;

[0051] Figure 9 A schematic diagram of the comprehensive results of X5 well (left) - X6 well (right) disclosed in the present application;

[0052] Figure 10 A schematic diagram of the device structure for identifying oil and gas layers based on the isochronous stratigraphic framework and fine stratigraphic correlation disclosed in the present application;

[0053] Figure 11 A schematic diagram of the electronic device disclosed in the present application. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0055] For the current reservoir evaluation method, the log curve shape of different formations may be similar, which can easily cause stratigraphic correlation error. Secondly, logging data can only reflect part of the formation information, and for complex formations, the similarity of logging curves is poor, and it is difficult to achieve accurate correlation. Thirdly, when the formation has a sudden change, the logging curve will appear abnormal, which seriously affects the accuracy of stratigraphic correlation. As a result, the same small layer between wells under lithostratigraphic correlation is not in the same sedimentary environment, and there are differences in formation water resistivity and litho-electric parameters. Accordingly, the oil and gas saturation calculated has no comparability between wells, and the measured resistivity, porosity and other logging curves also have no horizontal correlation significance, which is difficult to meet the needs of efficient oil and gas exploration and development. Therefore, the application provides a method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework, which can improve the accuracy and efficiency of oil and gas layer identification.

[0056] Referring to Figure 1 As shown in the figure, the embodiment of the application discloses a method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework, comprising:

[0057] Step S11, in the target oil and gas exploration area, determine a first sequence boundary set based on the logging curve characteristics, and determine a second sequence boundary set based on the well seismic information and the logging information.

[0058] In this embodiment, the well containing drilling core information and logging information is taken as a key well, and the core data is used to modify the logging information, so as to construct a standard profile of the key well based on the modified logging information. It should be noted that the key well contains more comprehensive and representative information, which can provide a solid data foundation for subsequent analysis. The operation of modifying the logging information by using the core data aims to further improve the reliability of the logging information. Core data is the most intuitive reflection of underground rock strata, and it is used to calibrate the logging information, so that the logging information can better fit the actual formation conditions. On this basis, the standard profile of the key well is constructed based on the modified logging information, which is like a precise reference system, providing a framework for subsequent determination of the sequence boundary set.

[0059] After the standard profile is determined, a first set of sequence boundaries is determined in the standard profile based on log curve features in the log information. Specifically, the log curve features include, but are not limited to, resistivity curve features, natural gamma curve, and the like. Different formations often have obvious differences in resistivity, natural gamma, and other log curve features. For example, sandstone formations can exhibit low natural gamma and high resistivity, while mudstone formations are the opposite, exhibiting high natural gamma and low resistivity. By analyzing the numerical changes, morphological features, and other details of these log curves, the interfaces dividing different sequences can be identified, and the first set of sequence boundaries can be determined. For example, the first set of sequence boundaries can be named sequence boundary a.

[0060] In this embodiment, a seismic synthetic record is determined based on the sonic curve and the density curve in the log information, and the seismic synthetic record is modified according to the seismic information near the well to obtain the seismic synthetic record satisfying the preset similarity condition. It should be noted that the sonic curve and the density curve each reflect different aspects of the physical properties of the formation, and they can be combined to generate a seismic synthetic record through specific technical means. This record simulates the response of the formation under seismic action to some extent. However, the initially generated seismic synthetic record may not fully meet the actual requirements, so it needs to be modified according to the seismic information near the well until the seismic synthetic record satisfying the preset similarity condition is obtained. The preset similarity condition is that the seismic synthetic record has the maximum similarity with the seismic information near the well.

[0061] Further, in this embodiment, a seismic profile of the key well is constructed based on the modified log information, and a second set of sequence boundaries is determined in the seismic profile using the seismic synthetic record satisfying the preset similarity condition. For example, the second set of sequence boundaries can be named sequence boundary b.

[0062] In step S12, a target set of sequence boundaries is determined in the first set of sequence boundaries and the second set of sequence boundaries based on a preset boundary determination rule, and an isochronous stratigraphic framework is determined using the target set of sequence boundaries to mark sequences in the isochronous stratigraphic framework.

[0063] It should be noted that the process of determining the target set of sequence boundaries in the first set of sequence boundaries and the second set of sequence boundaries needs to be performed under the constraint of the seismic profile, that is, the target set of sequence boundaries needs to be determined in the first set of sequence boundaries and the second set of sequence boundaries based on the preset boundary determination rule. It can be understood that the seismic profile can clearly show the distribution pattern, thickness variation, and continuity of the formation in the ground, and these information provides an intuitive and important reference for the correlation of sequence boundaries.

[0064] Once the target sequence interface set is determined, the isochronous stratigraphic framework can be determined based on the target sequence interface set. The constructed isochronous stratigraphic framework can be as follows: Figure 2 As shown in the figure, SH1, SH2, SH3, SH4, SH5, SH6, SH7, SH8, SH9, SH10 and SH11 are the 11 IV sequences marked in the isochronous stratigraphic framework, and the dividing line between the sequences is the sequence boundary. After subsequent operations, it can be determined that the oil and gas layers are mainly located in SH3, SH5 and SH8.

[0065] Step S13: Under the isochronous stratigraphic framework, the rock electrical parameters and formation water resistivity of each sequence are determined based on core data and the preset Archie formula. The target porosity evaluation model of each sequence is determined based on the three-porosity logging curve information and the core data, so as to determine the porosity of the sequence using the target porosity evaluation model.

[0066] In this embodiment, the determination of rock electrical parameters and formation water resistivity, as well as subsequent processes, are all conducted within an isochronous stratigraphic framework, i.e., under a relatively accurate and uniform geological background. Specifically, firstly, formation factors, porosity data, resistivity increase coefficient, water saturation, and formation water information are obtained from the core data.

[0067] Furthermore, in this embodiment, the rock electrical parameters of each sequence are determined based on the preset Archie formula, the formation factors, the porosity data, the resistivity increase coefficient, and the water saturation. These rock electrical parameters may include a (i.e., a lithology-related lithology coefficient), b (i.e., a lithology-related constant), and m (i.e., a lithology-related constant). And n (i.e., the saturation index). Additionally, the Archie formula for a pure water layer is as follows:

[0068] ;

[0069] In the formula, F represents the stratigraphic factor. This refers to porosity data. For specific examples, see, for instance. Figure 3 As shown, with formation factor F as the vertical axis and porosity as the horizontal axis... On a log-log coordinate system with x as the x-axis, the slope of the straight line is m. The ordinate of 100% is a. Therefore, we can first calculate F, ... The natural logarithmic values ​​were obtained, and then a cross plot was plotted to obtain the rock electrical parameters a=1.6223 and m=1.6729.

[0070] In this embodiment, the Archie formula for a pure oil layer is as follows:

[0071] ;

[0072] wherein I is a resistivity increase coefficient, S w is a water saturation. Specifically, for example, refer to Figure 4 , as shown in the figure, in the double logarithmic coordinates with the resistivity increase coefficient I as the longitudinal coordinate and the water saturation S w as the transverse coordinate, the slope of the straight line is n, and the longitudinal coordinate of S w =100% is b. Therefore, the natural logarithm values of I, S w may be obtained first, and then the intersection plot of the two is obtained, and b=1.0605 and n=1.508 in the rock electrical parameters are obtained.

[0073] Meanwhile, in the embodiment, the ion salinity in the formation water information is converted into equivalent NaCl salinity based on an equivalent coefficient of the ion salinity, and the formation water resistivity under experimental test conditions is determined by using the equivalent NaCl salinity. When the temperature in the experimental test is 24℃, the calculation formula of the formation water resistivity can be as follows:

[0074] ;

[0075] wherein R wl is the formation water resistivity, and P w is the equivalent NaCl salinity.

[0076] After the formation water resistivity under the experimental test conditions is calculated, the formation water resistivity under formation conditions is determined based on a preset conversion formula and the formation water resistivity under the experimental test conditions. The preset conversion formula is as follows:

[0077] ;

[0078] wherein R w is the formation water resistivity under formation conditions, T l and T f are the laboratory temperature (that is, the temperature under the experimental test conditions, 24℃) and the formation temperature respectively, and the calculation formula of T f is as follows:

[0079] ;

[0080] wherein T s is the surface temperature (unit: ℃), g D is the geothermal gradient (unit: ℃ / 100m), and H is the formation depth (unit: m).

[0081] In the embodiment, the rock electrical parameters and the formation water resistivity of SH3, SH5 and SH8 can be as shown in Table 1.

[0082] Table 1

[0083]

[0084] Further, in the embodiment, the porosity evaluation model of each sequence in the target oil and gas exploration area is determined. Specifically, the depth information in the core data is modified according to the depth information in the logging information, so as to obtain target depth information in which the depth information of the core data is consistent with the depth information in the logging information.

[0085] After obtaining the target depth information, the three-porosity logging curve information of the corresponding depth is obtained based on the target depth information, and the relationship information of the porosity data and the acoustic wave, density and neutron in the three-porosity logging curve information is determined respectively. For example, as shown in the following figure, it is the relationship image of the porosity data corresponding to SH5 and the acoustic wave, density and neutron in the three-porosity logging curve information. Figure 5 As can be seen from the figure, the correlation coefficient of the acoustic wave and the porosity data in SH5 is the best, while the density and the porosity data, the neutron and the porosity data are greatly affected by the lithology and the fluid in the pore, and the numerical value changes greatly, and the correlation with the porosity data is poor. Figure 5

[0086] In the embodiment, the relationship information is converted into a relationship curve, and single or multiple fitting is performed on the relationship curve and the porosity data to obtain each porosity evaluation model. In each porosity evaluation model, the porosity evaluation model that meets the preset correlation condition is determined as the target porosity evaluation model. In addition, as shown in Table 2, for the sequence of the above selected oil and gas layer, the neutron, density and acoustic wave ternary regression model is finally selected as the basis for calculating the porosity of SH3 formation, the acoustic wave unary regression model is selected as the basis for calculating the porosity of SH5 formation, and the neutron and acoustic wave binary regression model is selected as the basis for calculating the porosity of SH8 formation.

[0087] Table 2

[0088]

[0089] In step S14, the oil saturation of each sequence is determined based on the rock-electricity parameter, the formation water resistivity, the porosity and the preset Archie formula, and the reservoir unit correlation is performed based on the logging curve, so as to identify the oil and gas layer in each sequence by using the obtained correlation result, the porosity and the oil saturation.

[0090] In the embodiment, first, the water saturation of each sequence is determined according to the rock-electricity parameter, the formation water resistivity and the porosity, and the formula for calculating the water saturation is as follows:

[0091] ​ ;

[0092] In the formula, S w is the water saturation (unit: %), R t is the reservoir resistivity (unit: Ω·m).

[0093] The oil saturation of each sequence is determined based on the calculated water saturation and the oil saturation calculation formula. The oil saturation calculation formula is as follows:

[0094] S O = 1-S W ;

[0095] In the formula, S O is the oil saturation (unit: %).

[0096] Further, in the embodiment, the logging curve in the logging information that meets the preset sensitivity condition is determined as a correlation curve, and the reservoir units of the tested well and the to-be-tested well are correlated (i.e., small layer correlation) based on the correlation curve to obtain a correlation result. That is, the small layer correlation between the tested well and the to-be-tested well is performed by using the fact that the sand bodies deposited in the same period in space have similar logging curve characteristics. It should be emphasized that the tested well is a well that has been put into production or has complete coring data, logging data, relatively more logging series, and the related data of the tested well are relatively complete, but the completeness is less than that of the key well. In addition, the logging curve that meets the preset sensitivity condition can include a natural gamma curve, a lateral, an induction and a gradient resistivity curve.

[0097] Finally, the reservoir unit lithology and curve change information in the obtained correlation result are used to determine the reservoir type of each sequence based on the reservoir unit lithology, the curve change information, the porosity and the oil saturation, so as to determine the oil and gas layer in each sequence by using the reservoir type. In addition, referring to Table 3, the target oil and gas exploration area reservoir interpretation and evaluation standard required for finally determining the oil and gas layer can be established according to various information data, and the oil and gas layer in each sequence is determined by the target oil and gas exploration area reservoir interpretation and evaluation standard.

[0098] Table 3

[0099]

[0100] From the above, the first sequence interface set is obtained according to the logging curve characteristics, and the second sequence interface set is obtained according to the seismic information and the logging information. The target sequence interface set is determined according to a preset rule, and the isochronous stratigraphic framework is constructed and the sequence is calibrated. In the framework, the rock-electricity parameters and the formation water resistivity of the sequence are determined according to the core data and the preset Archie formula, the target porosity evaluation model is determined according to the three porosity logging curves and the core data to calculate the porosity. The oil saturation is calculated according to the rock-electricity parameters, the formation water resistivity, the porosity and the preset Archie formula. The reservoir unit comparison is carried out based on the logging curve, and the oil and gas layers in each sequence are identified according to the comparison result, the porosity and the oil saturation. In this way, the application can improve the accuracy and efficiency of oil and gas layer identification, thereby improving the user experience.

[0101] The technical solutions of the embodiments of the application will be described in detail below with reference to the schematic diagrams shown in Figure 6 、 Figure 7 、 Figure 8 and Figure 9 .

[0102] Specifically, in a specific embodiment, referring to Figure 6 and Figure 7 , the accuracy of the application is verified by referring to the test production results of the X2 well. Among them, Figure 6 is the X1 well, Figure 7 is the X2 well, the X1 well is the target well (i.e. the tested well), and the X2 well is the well to be evaluated (i.e. the well to be tested), both of which are located in the SH5 formation. Taking the 30th layer 3020m of the X2 well as an example to calculate the porosity and the oil saturation, the acoustic value AC is 248μs / m, the deep induced resistivity value Rt is 3.8Ω·m, and the rock-electricity parameters and the formation water resistivity are the above-mentioned values, i.e. a=1.0565, m=1.0752, b=1.0228, n=1.4942, and Rw=0.073. The calculation process of the porosity of the layer is as follows:

[0103] ;

[0104] In addition, the calculation process of the water saturation of the layer is as follows:

[0105] ;

[0106] Therefore, the oil saturation of the layer can be obtained by calculating the porosity and the water saturation of the layer, and the calculation process of the oil saturation is as follows:

[0107] ;

[0108] Comparing the target well X1 and the well to be evaluated X2, it is found that the natural gamma curves at 3152m of X1 and 3005.5m of X2 have similar characteristics, the deep induced resistivity curves at 3138.5m of X1 and 2995m of X2 have similar characteristics, and the 4-meter gradient curves at 3158m of X1 and 3014m of X2 have similar characteristics. Overall, the well logging curve characteristics of 2995-3064.4m of X2 are similar to those of 3138-3208m of X1, indicating that the sand bodies are deposited in the same period and have strong contrast.

[0109] Based on the comparison of the sand groups, the 3018-3052m interval of X2 corresponds to the 3166-3186m interval of X1 where industrial oil flow is obtained. The acoustic curve shows that the physical property of X2 is better than that of X1, the resistivity curve shows that the value of X2 is higher than that of X1, and the oil-bearing property is good. The calculated porosity is between 10% and 18%, and the oil saturation is greater than 50%. According to the established comprehensive reservoir interpretation standard (i.e., the reservoir interpretation and evaluation standard of the target oil and gas exploration area), the well X2 can be evaluated as an oil layer. In practice, the well X2 tests 10 tons of daily oil production without water, and the production conclusion is an oil layer.

[0110] In a specific embodiment, referring to FIG. 6, the accuracy of the present application is verified with reference to the test production results of the well X4. Figure 8 Figure 8 In a specific embodiment, referring to FIG. 6, the accuracy of the present application is verified with reference to the test production results of the well X4.

[0111] In a specific embodiment, referring to FIG. 6, the accuracy of the present application is verified with reference to the test production results of the well X4. Figure 9 Figure 9 ​​The comprehensive result map of well X5 (left) - well X6 (right) is shown in the middle, the left side is the target well X5, and the right side is the well to be evaluated X6, both of which are located in SH8 formation. By comparing the target well X5 and the well to be evaluated X6, it is found that the natural gamma ray, deep (middle) induction curves at 1792-1802m, 1810-1822m, 1837-1860m of well X5 respectively have similar characteristics with 1936-1839m, 1840-1855m, 1878-1900m of well X6, which indicates that the sand bodies are deposited in the same period. The logging data shows that well X5 and well X6 are both gray sandstone, the sand body thickness of well X6 is larger, the deep middle induction resistivity value is slightly higher, the physical properties of the two wells are equivalent, well X5 tests obtain industrial oil flow, according to the sand body comparison results of the two wells, combined with the established reservoir comprehensive interpretation standard, the 27-30, 33, 35-37, 39 layers of well X6 are evaluated as oil layers, the daily oil production of the test is 16.1 tons, and there is no water, the production conclusion is oil layer.

[0112] Correspondingly, referring to Figure 10 The embodiments of the present application provide an oil and gas layer identification device based on isochronous stratigraphic framework stratigraphic fine correlation, which comprises:

[0113] An interface determination module 11 is configured to determine a first sequence interface set based on logging curve characteristics in a target oil and gas exploration area, and determine a second sequence interface set based on well seismic information and logging information;

[0114] A framework determination module 12 is configured to determine a target sequence interface set in the first sequence interface set and the second sequence interface set based on a preset interface determination rule, and determine an isochronous stratigraphic framework by using the target sequence interface set, so as to calibrate sequences in the isochronous stratigraphic framework;

[0115] A porosity determination module 13 is configured to determine rock-electricity parameters and formation water resistivity of each sequence based on core data and a preset Archie formula under the isochronous stratigraphic framework, and determine a target porosity evaluation model of each sequence based on three porosity logging curve information and the core data, so as to determine the porosity of the sequence by using the target porosity evaluation model;

[0116] An oil and gas layer identification module 14 is configured to determine oil saturation of each sequence based on the rock-electricity parameters, the formation water resistivity, the porosity and the preset Archie formula, and perform reservoir unit correlation based on logging curves, so as to identify oil and gas layers in each sequence by using the obtained correlation results, the porosity and the oil saturation.

[0117] From the above, the first sequence interface set is obtained according to the logging curve characteristics, and the second sequence interface set is obtained according to the seismic information and the logging information. The target sequence interface set is determined according to a preset rule, and the isochronous stratigraphic framework is constructed and the sequence is calibrated. In the framework, the rock-electricity parameters and the formation water resistivity of the sequence are determined by the core data and the preset Archie formula, the target porosity evaluation model is determined according to the three porosity logging curves and the core data to calculate the porosity. The oil saturation is calculated according to the rock-electricity parameters, the formation water resistivity, the porosity and the preset Archie formula. The reservoir units are compared based on the logging curves, and the oil and gas layers in each sequence are identified according to the comparison results, the porosity and the oil saturation. In this way, the application can improve the accuracy and efficiency of oil and gas layer identification, thereby improving the user experience.

[0118] In a specific embodiment, the interface determination module 11 specifically comprises:

[0119] A standard profile construction unit is configured to take a well containing drilling core information and logging information as a key well, modify the logging information by using core data, and construct a standard profile of the key well based on the modified logging information.

[0120] A first interface set determination unit is configured to determine a first sequence interface set in the standard profile based on logging curve characteristics in the logging information.

[0121] In a specific embodiment, the interface determination module 11 specifically comprises:

[0122] A record determination unit is configured to determine a seismic synthetic record based on a sonic curve and a density curve in the logging information, and modify the seismic synthetic record according to the seismic information near the well to obtain the seismic synthetic record satisfying a preset similarity condition.

[0123] A second interface set determination unit is configured to construct a seismic profile of the key well based on the modified logging information, and determine a second sequence interface set in the seismic profile by using the seismic synthetic record satisfying the preset similarity condition.

[0124] In a specific embodiment, the porosity determination module 13 specifically comprises:

[0125] An information acquisition unit is configured to acquire formation factors, porosity data, resistivity increase coefficients, water saturation and formation water information in the core data.

[0126] A rock-electricity parameter determination unit is configured to determine rock-electricity parameters of each sequence based on a preset Archie formula, the formation factors, the porosity data, the resistivity increase coefficients and the water saturation.

[0127] The first resistivity determining unit is configured to convert the ion salinity in the formation water information into equivalent NaCl salinity based on an equivalent coefficient of the ion salinity, and determine the formation water resistivity under the experimental test condition by using the equivalent NaCl salinity.

[0128] The second resistivity determining unit is configured to determine the formation water resistivity under the formation condition based on a preset conversion formula and the formation water resistivity under the experimental test condition.

[0129] In an embodiment, the porosity determining module 13 specifically comprises:

[0130] The depth information determining unit is configured to modify the depth information in the core data according to the depth information in the logging information, so as to obtain target depth information in which the depth information of the core data is consistent with the depth information in the logging information.

[0131] The relationship information determining unit is configured to obtain the three-porosity logging curve information at the corresponding depth based on the target depth information, and determine the relationship information of the acoustic wave, the density and the neutron in the porosity data and the three-porosity logging curve information, respectively.

[0132] Each model determining unit is configured to convert the relationship information into a relationship curve, and perform single-item fitting or multi-item fitting by using the relationship curve and the porosity data, so as to obtain each porosity evaluation model.

[0133] The target model determining unit is configured to determine, among the porosity evaluation models, a porosity evaluation model that meets a preset correlation condition as a target porosity evaluation model.

[0134] In an embodiment, the oil and gas layer identifying module 14 specifically comprises:

[0135] The unit comparison unit is configured to determine, as a comparison curve, a logging curve in the logging information that meets a preset sensitivity condition, and perform reservoir unit comparison between the tested well and the to-be-tested well based on the comparison curve, so as to obtain a comparison result.

[0136] In an embodiment, the oil and gas layer identifying module 14 specifically comprises:

[0137] The information obtaining unit is configured to obtain the reservoir unit lithology and the curve change information in the obtained comparison result.

[0138] The oil and gas layer identifying unit is configured to determine the reservoir type of each of the sequences based on the reservoir unit lithology, the curve change information, the porosity and the oil saturation, so as to determine the oil and gas layer in each of the sequences by using the reservoir type.

[0139] Further, the embodiment of the present application further discloses an electronic device, Figure 11 is a structural diagram of the electronic device 20 according to an exemplary embodiment, and the content in the figure cannot be considered as any limitation on the use range of the present application. The electronic device 20 can specifically include at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25 and a communication bus 26. The memory 22 is used for storing a computer program, and the computer program is loaded and executed by the processor 21 to realize the related steps in the method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework disclosed in any of the foregoing embodiments. In addition, the electronic device 20 in the embodiment can be specifically an electronic computer.

[0140] In the embodiment, the power supply 23 is used for providing working voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol followed by the communication interface 24 can be any communication protocol applicable to the technical solution of the present application, which is not limited specifically herein; the input / output interface 25 is used for obtaining external input data or outputting data to the outside, and the specific interface type can be selected according to the specific application needs, which is not limited specifically herein.

[0141] In addition, the memory 22 as a carrier for resource storage can be a read-only memory, a random access memory, a magnetic disk or an optical disk, etc., and the resources stored thereon can include an operating system 221, a computer program 222, etc., and the storage mode can be temporary storage or permanent storage.

[0142] The operating system 221 is used for managing and controlling each hardware device on the electronic device 20 and the computer program 222, and can be Windows Server, Netware, Unix, Linux, etc. In addition to the computer program capable of completing the method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework executed by the electronic device 20 disclosed in any of the foregoing embodiments, the computer program 222 can further include a computer program capable of completing other specific work.

[0143] Further, the present application further discloses a computer readable storage medium for storing a computer program; wherein the computer program is executed by a processor to realize the method for identifying oil and gas layers based on fine stratigraphic correlation of isochronous stratigraphic framework disclosed in the foregoing embodiment. The specific steps of the method can refer to the corresponding content disclosed in the foregoing embodiment, which will not be repeated here.

[0144] The various embodiments described in the specification are progressive in nature, and each embodiment highlights the differences from other embodiments. The same or similar parts among the various embodiments can be mutually referred to. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0145] Those skilled in the art will further appreciate that the individual steps of the examples described in connection with the embodiments disclosed herein can be embodied in electronic hardware, computer software, or combinations of both. The various examples have been described in relation to the described embodiments, as a means of generalizing the interchangeability of hardware and software. Whether employing hardware or software, the described functionality is implemented as desired by the particular application and design constraints. Skilled artisans appreciate that the replacement of one part by a different part, the addition of new parts, or the omission of existing parts, can be made without departing from the scope of the present application.

[0146] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in random access memory (RAM), flash memory, read-only memory (ROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0147] Finally, it needs to be pointed out that, in this document, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or sequence between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0148] The above describes the technical solutions provided by the present application in detail, and the principles and implementation manners of the present application are described by using specific examples. The above description of the embodiments is only to help understand the method and its core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range can be changed, and the above description of the specification should not be understood as limiting the present application.

Claims

1. A method for identifying hydrocarbon reservoirs based on fine stratigraphic correlation using an isochronous stratigraphic framework, characterized in that, include: In the target oil and gas exploration area, the first sequence interface set is determined based on the characteristics of well logging curves, and the second sequence interface set is determined based on well-side seismic information and well logging information. Based on the preset interface determination rules, a target sequence interface set is determined in the first sequence interface set and the second sequence interface set, and the target sequence interface set is used to determine the isochronous stratigraphic grid, so as to mark the sequence in the isochronous stratigraphic grid. Under the aforementioned isochronous stratigraphic framework, the rock electrical parameters and formation water resistivity of each sequence are determined based on core data and the preset Archie formula. A target porosity evaluation model for each sequence is then determined based on the three-porosity logging curve information and the core data, in order to determine the porosity of the sequence using the target porosity evaluation model. The oil saturation of each sequence is determined based on the rock electrical parameters, formation water resistivity, porosity, and the preset Archie formula. Reservoir units are compared based on well logging curves, and the oil and gas layers in each sequence are identified using the comparison results, porosity, and oil saturation. The determination of the first sequence interface set based on well logging curve characteristics includes: Wells containing drilling core information and logging information are designated as key wells, and the logging information is modified using core data to construct a standard profile of the key well based on the modified logging information. In the standard profile, the first sequence interface set is determined based on the logging curve characteristics in the logging information; The determination of the second sequence interface set based on well-side seismic information and well logging information includes: Based on the sonic curves and density curves in the well logging information, the seismic composite record is determined, and the seismic composite record is modified according to the well-side seismic information to obtain the seismic composite record that meets the preset similarity conditions. Based on the modified well logging information, a seismic profile of the key well is constructed, and the second sequence interface set is determined in the seismic profile using the seismic synthetic record that meets the preset similarity conditions.

2. The method for identifying hydrocarbon reservoirs based on fine stratigraphic correlation using an isochronous stratigraphic framework as described in claim 1, characterized in that, The determination of the rock electrical parameters and formation water resistivity of each sequence based on core data and a pre-defined Archie formula includes: Obtain formation factors, porosity data, resistivity increase coefficient, water saturation, and formation water information from the core data; The rock electrical parameters of each sequence are determined based on the preset Archie formula, the formation factors, the porosity data, the resistivity increase coefficient, and the water saturation. Based on the equivalent coefficient of ion mineralization in the formation water information, the ion mineralization is converted into equivalent NaCl mineralization, and the formation water resistivity under experimental test conditions is determined using the equivalent NaCl mineralization. The formation water resistivity under the specified formation conditions is determined based on the preset conversion formula and the formation water resistivity under the experimental test conditions.

3. The method for identifying hydrocarbon reservoirs based on fine stratigraphic correlation using an isochronous stratigraphic framework as described in claim 2, characterized in that, The method for determining the target porosity evaluation model for each sequence based on three-porosity logging curve information and core data includes: The depth information in the core data is modified based on the depth information in the well logging information to obtain target depth information that is consistent with the depth information in the well logging information; Based on the target depth information, obtain the corresponding depth three-porosity logging curve information, and determine the relationship information of acoustic waves, density and neutrons in the porosity data and the three-porosity logging curve information respectively; The relationship information is converted into a relationship curve, and the relationship curve and the porosity data are used to perform single or multiple fitting to obtain each porosity evaluation model. Among the porosity evaluation models, the porosity evaluation model that meets the preset correlation conditions is determined as the target porosity evaluation model.

4. The method for identifying hydrocarbon reservoirs based on fine stratigraphic correlation using an isochronous stratigraphic framework according to any one of claims 1 to 3, characterized in that, The reservoir unit comparison based on well logging curves includes: The logging curves that meet the preset sensitivity conditions in the logging information are determined as comparison curves, and the reservoir units of the tested wells and the wells to be tested are compared based on the comparison curves to obtain comparison results.

5. The method for identifying oil and gas reservoirs based on fine stratigraphic correlation using an isochronous stratigraphic framework according to claim 1, characterized in that, The method of identifying oil and gas layers in each sequence using the obtained comparison results, the porosity, and the oil saturation includes: Obtain information on reservoir unit lithology and curve variation from the obtained comparison results; Based on the lithology of the reservoir unit, the curve variation information, the porosity, and the oil saturation, the reservoir type of each sequence is determined, so as to use the reservoir type to determine the oil and gas layers in each sequence.

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