Water saturation prediction method and device, storage medium and electronic equipment

Abstract

The invention provides a water saturation prediction method and device, a storage medium and electronic equipment, and solves the problem of water saturation calculation of a heterogeneous reservoir. The water saturation prediction method provided by the invention comprises the following steps: acquiring an interface polarization frequency when a rock completely contains water and an interface polarization frequency when the rock contains oil; predicting the water saturation of the rock by using a pre-constructed water saturation interpretation model; wherein the water saturation interpretation model represents the relationship between the interface polarization frequency when the rock completely contains water, the interface polarization frequency when the rock contains oil and the water saturation of the rock. The water saturation calculated by using the interpretation model is better in correlation with the actual saturation and higher in fitting degree.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration, and in particular to a water saturation prediction method, device, storage medium and electronic equipment. Background Art

[0002] Resistivity logging was invented in the 1920s, but at that time, resistivity data could only be used to qualitatively identify oil, gas, and water layers, and to divide the lithology of the formations, but it could not be used to quantitatively interpret and evaluate the reservoirs. It was not until the publication of Archie's formula in 1942 that researchers established a set of quantitative evaluation techniques for reservoir oil and gas saturation based on Archie's formula, establishing a connection between logging theory and logging practice. After that, researchers repeated Archie's experiment based on their own rock samples to obtain rock electrical parameters for oil saturation calculation. Practical applications have shown that the rock electrical parameters obtained from a small number of rock samples in a single well cannot meet the interpretation of the reservoir of the entire well section or block, and the calculation error of the oil saturation of some layers is large, which affects the evaluation of oil and water layers. In response to these problems, researchers modified Archie's formula based on geological conditions and derived various extended formulas to improve the calculation accuracy of oil saturation. Even so, these formulas are not very effective in mud sandstone, low-resistance reservoirs, and complex pore reservoirs. In view of this situation, it is expected to adopt a new logging technology to solve the problem of water saturation calculation in heterogeneous reservoirs. Summary of the invention

[0003] The present invention provides a water saturation prediction method, device, storage medium and electronic equipment, which solve the problem of water saturation calculation of heterogeneous reservoirs.

[0004] In a first aspect, an embodiment of the present invention provides a method for predicting water saturation, comprising:

[0005] Obtain the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing;

[0006] Use the pre-built water saturation interpretation model to predict the water saturation of the rock;

[0007] The water saturation interpretation model characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, and the water saturation of the rock.

[0008] In some implementations, the water saturation interpretation model is as follows:

[0009]

[0010] Among them, S w Indicates the water saturation of rock, A f , B frepresents a constant, n' represents a dielectric saturation index similar to the saturation index, b' represents a coefficient, and f 0 represents the interfacial polarization frequency when the rock is fully hydrated, f t Represents the interfacial polarization frequency when the rock contains oil.

[0011] In some implementations, the method further includes:

[0012] Establish the relationship between the complex resistivity of rock and the interface polarization frequency, which is used to characterize the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, the complex resistivity when the rock is completely water-containing, and the complex resistivity when the rock is oil-containing;

[0013] Establish the expression of interface polarization frequency change rate, which is used to characterize the interface polarization frequency of rock containing oil, the interface polarization frequency of rock containing water completely, and the relationship between the water saturation of rock and the interface polarization frequency change rate;

[0014] Based on the relationship between the complex resistivity of the rock and the interface polarization frequency and the expression for the rate of change of the interface polarization frequency, a water saturation interpretation model is constructed.

[0015] In some implementations, establishing a relationship between the complex resistivity of the rock and the interface polarization frequency includes:

[0016] Collect rock samples and conduct electrical spectrum measurement experiments on rock samples;

[0017] The influence of rock water saturation on interface polarization frequency is analyzed, and the relationship between rock complex resistivity and interface polarization frequency is established.

[0018] In some implementations, the relationship between the complex resistivity of the rock and the interface polarization frequency is as follows:

[0019]

[0020] Among them, f 0 represents the interfacial polarization frequency when the rock is fully hydrated, f t represents the interfacial polarization frequency when the rock contains oil, R 0 Represents the complex resistivity of the rock when it is completely water-containing, R t Indicates the complex resistivity of rock containing oil, A f , B f Represents a constant.

[0021] In some implementations, the interface polarization frequency change rate expression is as follows:

[0022]

[0023] Among them, If represents the rate of change of interface polarization frequency, f t represents the interfacial polarization frequency when the rock contains oil, f 0 represents the interfacial polarization frequency when the rock is fully hydrated, S w represents the water saturation of rock, n' represents the dielectric saturation index similar to the saturation index, and b' represents the coefficient.

[0024] In a second aspect, an embodiment of the present invention provides a water saturation prediction device, comprising:

[0025] An acquisition module, used to acquire the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing;

[0026] A prediction module is used to predict the water saturation of rocks using a pre-built water saturation interpretation model;

[0027] The water saturation interpretation model characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, and the water saturation of the rock.

[0028] In some implementations, the water saturation interpretation model is as follows:

[0029]

[0030] Among them, S w Indicates the water saturation of rock, A f , B f represents a constant, n' represents a dielectric saturation index similar to the saturation index, b' represents a coefficient, and f 0 represents the interfacial polarization frequency when the rock is fully hydrated, f t Represents the interfacial polarization frequency when the rock contains oil.

[0031] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by at least one processor, the method described in the first aspect is implemented.

[0032] In a fourth aspect, an embodiment of the present invention provides an electronic device, comprising a memory and at least one processor, wherein the memory stores a computer program, and when the computer program is executed by the at least one processor, the method described in the first aspect is implemented.

[0033] The embodiments of the present invention can at least bring the following beneficial effects:

[0034] The water saturation prediction method provided by the present invention obtains the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing; uses a pre-constructed water saturation interpretation model to predict the water saturation of the rock; the water saturation interpretation model characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing and the water saturation of the rock, and the water saturation calculated using the interpretation model has a better correlation with the actual saturation and a higher degree of fit. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope.

[0036] Figure 1 is a flow chart of a method for predicting water saturation provided by an embodiment of the present invention;

[0037] Figure 2 is a frequency-real resistivity cross-plot under different water saturation conditions provided by an embodiment of the present invention;

[0038] Figure 3 is a frequency-imaginary resistivity crossplot under different water saturation conditions provided by an embodiment of the present invention;

[0039] Figure 4 is a diagram showing the relationship between relaxation time and water saturation provided by an embodiment of the present invention;

[0040] Figure 5 is a diagram showing the effect of water saturation on low-frequency complex resistivity provided by an embodiment of the present invention;

[0041] Figure 6 is a diagram showing the effect of water saturation on relaxation time provided by an embodiment of the present invention;

[0042] Figure 7 is a diagram showing the effect of water saturation on interface polarization frequency provided by an embodiment of the present invention;

[0043] Figure 8 is a graph showing the relationship between the interface polarization frequency and the water saturation provided by an embodiment of the present invention;

[0044] Fig. 9 is a graph showing the relationship between the interface polarization frequency and the low frequency (1 KHz) complex resistivity provided by an embodiment of the present invention;

[0045] Fig.10 is a block diagram of a water saturation prediction device provided by an embodiment of the present invention;

[0046] Fig.11It is a comparison diagram of the saturation calculated and the measured saturation value of the interface polarization frequency provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0048] The phenomenon that the electrical characteristic parameters of rocks change with the measurement frequency is called the electrical dispersion of rocks. Since Hoyer and Rumble discovered in 1976 that induced polarization is related to the electrical dispersion of reservoir rocks when studying the complex resistivity of formations, and linked the measurement method of induced polarization with the rock dispersion phenomenon, proving that the complex resistivity of formations in argillaceous sandstone is related to the cation exchange capacity, the research based on the electrical dispersion of rocks has begun to develop.

[0049] Scholars have begun to carry out a lot of research on rock electrical spectrum and frequency, porosity, water saturation, rock structure and other aspects. Technical branches such as impedance dispersion, phase dispersion, resistivity dispersion, permittivity dispersion, inductance dispersion, dielectric dispersion, real dispersion, and imaginary dispersion have emerged in succession, and each technical branch has achieved a certain degree of phased results.

[0050] Based on the complex resistivity dispersion characteristics of fractures and fractured reservoirs in the low frequency band (100Hz~1MHz), Pan Baozhi and other scholars used finite element simulation to calculate the complex resistivity of a simple rock sample model, and studied the difference in the complex resistivity dispersion characteristics of homogeneous rock samples and fractured rock samples under a fully saturated water state. A saturation prediction formula was proposed based on the dielectric constant. However, the water saturation predicted by this prediction formula has a poor correlation with the actual saturation, and the fitting degree is not high, making it difficult to accurately reflect the true water saturation.

[0051] The present invention provides a water saturation prediction method, device, storage medium and electronic device according to the following embodiments, which solve the problem of water saturation calculation in heterogeneous reservoirs, so that the predicted water saturation has a good correlation with the actual saturation and a high degree of fit, and can more realistically reflect the water saturation, thereby improving the fluid identification and saturation calculation accuracy of complex oil and gas layers.

[0052] Embodiment 1

[0053] like Figure 1 As shown, the water saturation prediction method provided in this embodiment includes:

[0054] Step S101, obtaining the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing;

[0055] Step S102: using a pre-built water saturation interpretation model to predict the water saturation of the rock;

[0056] Among them, the water saturation interpretation model characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing and the water saturation of the rock.

[0057] The method of this embodiment can obtain the water saturation of the rock by using the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing, and using a pre-constructed water saturation interpretation model. The interface polarization frequency, as an electrical spectrum parameter of the rock, has a certain functional relationship with the water saturation and has a high correlation. Therefore, by pre-constructing an interpretation model that characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, and the water saturation of the rock, a relatively accurate rock water saturation can be calculated, and the water saturation of the tight reservoir can be effectively predicted, providing an accurate basis for subsequent exploration work and improving exploration efficiency.

[0058] In some implementations, the water saturation interpretation model is as follows:

[0059]

[0060] Among them, S w Indicates the water saturation of rock, A f , B f represents a constant, n' represents a dielectric saturation index similar to the saturation index, b' represents a coefficient, and f 0 represents the interfacial polarization frequency when the rock is fully hydrated, f t Represents the interfacial polarization frequency when the rock contains oil.

[0061] In practical applications, the above prediction method further includes steps S201 to S203:

[0062] Step S201, establish a relationship between the complex resistivity of the rock and the interface polarization frequency, which is used to characterize the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, the complex resistivity when the rock is completely water-containing, and the complex resistivity when the rock is oil-containing.

[0063] In an application example, taking the rock samples of tight reservoirs in the Sichuan Basin as an example, the relationship between the water saturation of the rock and the electrical dispersion of the rock was analyzed, and a water saturation interpretation model based on the electrical spectrum parameters (interface polarization frequency) was established, that is, a water saturation interpretation model was established. The relationship between the complex resistivity of the rock and the interface polarization frequency can be further included:

[0064] Step S201a: collect rock samples and conduct an electrical spectrum measurement experiment on the rock samples.

[0065] The rock structure of the tight reservoir in the Sichuan Basin is complex. The method of calculating water saturation using conventional logging data has been developed for many years, and the research ideas have certain limitations. Therefore, we conducted rock electrical dispersion experiments in the 1Hz-1KHz frequency range, analyzed the relationship between water saturation and dispersion, and conducted research on new methods for calculating water saturation, providing useful exploration for the calculation of water saturation in tight reservoirs.

[0066] First, a total of 30 rock samples from the tight reservoir in the Sichuan Basin were collected and the low-frequency rock sample electrical spectrum measurement experiment was carried out:

[0067] (1) 12 of the rock samples were placed at T = 16 °C (the remaining 18 rock samples were of lower reference value and were not considered here). w =50kppm, the influence of different water saturations (the water saturations are 100%, 93.5%, 88.2%, 75.1%, 64.6%, and 51.2%) of rock samples on the electrical spectrum (real resistivity R and imaginary resistivity X) of complex resistivity and electrical spectrum parameters (low-frequency resistivity, relaxation time, and interface polarization frequency) in the low-frequency range (40Hz-100MHz) is studied.

[0068] (2) The electrical spectra of complex resistivity of 30 rock samples in a saturated state (water saturation of 100%) were measured in the low frequency range (40 Hz to 100 MHz).

[0069] Then, the influence of water saturation on the electrical spectrum and the electrical spectrum parameters of rock complex resistivity is analyzed.

[0070] (1) Effect of water saturation on electrical spectrum

[0071] Taking rock sample No. 3 as an example, according to the measured data of real resistivity R and imaginary resistivity X in the low-frequency range at different water saturations, frequency-real resistivity crossplots under different water saturations were established respectively ( Figure 2 ) and frequency-imaginary resistivity crossplots at different water saturation states ( Figure 3 ), and analyze the changing trends of real resistivity and imaginary resistivity under different water saturation states.

[0072] The performance of the real resistivity R is as follows: when the water saturation is fixed, in the lower frequency range, the real resistivity R decreases slowly with the increase of frequency, and in the larger frequency range, R drops sharply and finally tends to be gentle and close to 0, see Figure 2 By comparing the experimental data of different water saturations, it can be found that the greater the water saturation, the smaller the real resistivity.

[0073] The performance of the imaginary resistivity X is as follows: when the water saturation is fixed, the amplitude of the imaginary resistivity X increases with the increase of frequency, reaches a maximum value, decreases with the increase of frequency, and finally tends to a stable value, and is close to 0, see Figure 3 By comparing the experimental data of different water saturations, it can be found that: with the increase of water saturation, the amplitude of imaginary resistivity decreases, and the imaginary valley frequency (interface polarization frequency f c ) decreases with the decrease of water saturation. The relaxation time τ increases with the decrease of water saturation, such as Figure 4 shown.

[0074] Step S201b, analyzing the influence of the water saturation of the rock on the interface polarization frequency, and establishing a relationship between the complex resistivity of the rock and the interface polarization frequency.

[0075] Taking rock sample No. 3 as an example, based on the measured electrical spectrum parameter data such as low-frequency resistivity, relaxation time, interface polarization frequency, etc. at different water saturations in the low-frequency range, frequency-low-frequency resistivity crossplots under different saturation states are established respectively ( Figure 5 ), frequency-relaxation time cross-plots under different saturation states ( Figure 6 ), frequency-interface polarization frequency cross-plots under different saturation states ( Figure 7 ), and analyze the changing trends of parameters such as low-frequency resistivity, relaxation time, and interface polarization frequency under different water saturation states.

[0076] The results show that as the water saturation of the rock increases, the low-frequency resistivity of the rock decreases, the relaxation time decreases, and the interface polarization frequency increases. Figures 5 to 7 The rock water saturation and the electrical spectrum parameters have a power function relationship and a high correlation.

[0077] In this embodiment, the Cole-Cole model can be used to fit the experimental curve, and the relationship between the complex resistivity and the relaxation time (constant, not a variable factor) and other electrical spectrum parameters under low frequency (1kHz) conditions can be obtained by inversion, and the interface polarization frequency is read on the electrical spectrum to study the relationship between the electrical spectrum parameters and water saturation. Furthermore, the relationship between the Cole-Cole model and the formation parameters (interface polarization frequency, Iε dielectric constant change rate, mineralization, porosity, temperature, etc.) is quantitatively established in combination with the experimental data of the rock sample to obtain a water saturation interpretation model based on the interface polarization frequency.

[0078] The relationship between the interface polarization frequency and water saturation is statistically analyzed for rock samples. Figure 8 It can be seen that the interface polarization frequency f c and water saturation S w It is a power function relationship. It satisfies the following formula:

[0079]

[0080] In the formula, S w is water saturation, A f , B f is a constant. The fit between the interface polarization frequency and water saturation in this formula is low.

[0081] Fig. 9 It is the relationship between the interface polarization frequency of the rock sample and the complex resistivity under low frequency (1KHz) conditions. Through the analysis of the experimental data, it can be found that when the frequency is not zero, the interface polarization frequency f c Satisfy the following formula:

[0082]

[0083] In a specific implementation, the relationship between the complex resistivity of rock and the interface polarization frequency is established as follows:

[0084]

[0085] Among them, f 0 represents the interfacial polarization frequency when the rock is fully hydrated, f t represents the interfacial polarization frequency when the rock contains oil, R 0 Represents the complex resistivity of the rock when it is completely water-containing, R t Indicates the complex resistivity of rock containing oil, A f , B f Represents a constant.

[0086] Step S202, establishing an interface polarization frequency change rate expression, which is used to characterize the interface polarization frequency when the rock contains oil, the interface polarization frequency when the rock contains complete water, and the relationship between the water saturation of the rock and the interface polarization frequency change rate;

[0087] In related technologies, Pan Baozhi et al. proposed the following water saturation prediction formula based on the dielectric constant:

[0088]

[0089] In the formula, I ε is the rate of change of dielectric constant, ε s is the relative dielectric constant of 100% water-bearing rock, ε r is the relative dielectric constant of rock. n' is the dielectric saturation index similar to the saturation index, and b' is the coefficient.

[0090] However, the water saturation obtained by this prediction formula has insufficient correlation with the actual water saturation and the fit is poor.

[0091] In a specific implementation of this embodiment, based on the established relationship between the complex resistivity of rock and the interface polarization frequency, the interface polarization frequency is processed to obtain the following expression of the interface polarization frequency change rate:

[0092]

[0093] Among them, I f represents the rate of change of interface polarization frequency, f t represents the interfacial polarization frequency when the rock contains oil, f 0 represents the interfacial polarization frequency when the rock is fully hydrated, S w represents the water saturation of rock, n' represents the dielectric saturation index similar to the saturation index, and b' represents the coefficient.

[0094] Step S203: Based on the relationship between the complex resistivity of the rock and the interface polarization frequency and the expression of the interface polarization frequency change rate, a water saturation interpretation model is constructed through numerical simulation.

[0095] In some cases, Archie's formula can be combined Will Calculate the reciprocal and substitute In this case, we get:

[0096] In the formula, except S w , f t , f 0 , the remaining parameters are constants. a, b, m, and n in Archie's formula represent constants. is the porosity.

[0097] The explanatory model is a power function model, for example, A f =0.967, B f =-0.246, f 0 / f t As a known quantity, the unknown quantity - water saturation can be solved Sw .

[0098] Based on the correspondence between water saturation and the spectrum parameters obtained by inversion, a water saturation interpretation model for the reservoir based on electrical spectrum parameters (interface polarization frequency) is established through numerical simulation. The water saturation calculated based on this interpretation model has a better correlation with the actual saturation and a higher degree of fit. By exploring the relationship between the dispersion characteristics of complex resistivity and water saturation, the accuracy of fluid identification and saturation calculation in complex oil and gas layers can be improved, providing a new method for water saturation calculation in tight reservoirs.

[0099] Embodiment 2

[0100] like Fig.10 As shown, this embodiment provides a water saturation prediction device, including:

[0101] An acquisition module 1001 is used to acquire the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing;

[0102] Prediction module 1002, used to predict the water saturation of rock using a pre-built water saturation interpretation model;

[0103] Among them, the water saturation interpretation model characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing and the water saturation of the rock.

[0104] In some implementations, the water saturation interpretation model is as follows:

[0105]

[0106] Among them, S w Indicates the water saturation of rock, A f , B f represents a constant, n' represents a dielectric saturation index similar to the saturation index, b' represents a coefficient, and f 0 represents the interfacial polarization frequency when the rock is fully hydrated, f t Represents the interfacial polarization frequency when the rock contains oil.

[0107] In practical applications, the above prediction device further includes a construction module for:

[0108] Establish the relationship between the complex resistivity of rock and the interface polarization frequency, which is used to characterize the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, the complex resistivity when the rock is completely water-containing, and the complex resistivity when the rock is oil-containing;

[0109] Establishing an expression for the change rate of interface polarization frequency to characterize the relationship between the interface polarization frequency when the rock contains oil, the interface polarization frequency when the rock contains complete water, and the water saturation of the rock and the change rate of interface polarization frequency; and

[0110] Based on the relationship between the complex resistivity of rock and the interface polarization frequency and the expression of the interface polarization frequency change rate, a water saturation interpretation model was constructed through numerical simulation.

[0111] The water saturation interpretation model in the device of this embodiment is constructed based on the relationship between the interfacial polarization frequency when the rock is completely water-containing, the interfacial polarization frequency when the rock contains oil, and the water saturation of the rock. The water saturation calculated using this interpretation model has a better correlation with the actual saturation and a higher degree of fit.

[0112] Embodiment 3

[0113] This embodiment provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by at least one processor, the method of the above embodiment is implemented.

[0114] Among them, the computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, disk or optical disk.

[0115] Embodiment 4

[0116] This embodiment provides an electronic device, including a memory and at least one processor. The memory stores a computer program, and when the computer program is executed by the at least one processor, the method of the above embodiment is implemented.

[0117] Among them, the processor can be an application specific integrated circuit (Application Specific Integrated Circuit, referred to as ASIC), a digital signal processor (Digital Signal Processor, referred to as DSP), a digital signal processing device (Digital Signal Processing Device, referred to as DSPD), a programmable logic device (Programmable Logic Device, referred to as PLD), a field programmable gate array (Field Programmable Gate Array, referred to as FPGA), a controller, a microcontroller (Microcontroller Unit, MCU), a microprocessor or other electronic components to implement the methods in the above embodiments.

[0118] Embodiment 5

[0119] Before conducting rock electrical dispersion experiments on tight reservoir rock samples collected in the Sichuan Basin, water saturation measurements were first performed to obtain the original water saturation S of the rock samples. w The water saturation interpretation model established by the present invention is then used to calculate the water saturation S wf , S w With S wf The comparison and verification showed that the agreement was high, proving the effectiveness of this method. Fig.11 .

[0120] In the several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed apparatus and method can also be implemented in other ways. The apparatus and method embodiments described above are merely illustrative.

[0121] It should be noted that, in this article, the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0122] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A method for predicting water saturation, characterized in that: include: Obtain the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing; Use the pre-built water saturation interpretation model to predict the water saturation of the rock; The water saturation interpretation model characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, and the water saturation of the rock.

2. The water saturation prediction method according to claim 1, characterized in that: The water saturation interpretation model is as follows: Among them, S w Indicates the water saturation of rock, A f , B f represents a constant, n' represents a dielectric saturation index similar to the saturation index, b' represents a coefficient, f0 represents the interfacial polarization frequency when the rock is fully water-containing, and f t Represents the interfacial polarization frequency when the rock contains oil.

3. The water saturation prediction method according to claim 1, characterized in that: Also includes: Establish the relationship between the complex resistivity of rock and the interface polarization frequency, which is used to characterize the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, the complex resistivity when the rock is completely water-containing, and the complex resistivity when the rock is oil-containing; Establish the expression of interface polarization frequency change rate, which is used to characterize the interface polarization frequency of rock containing oil, the interface polarization frequency of rock containing water completely, and the relationship between the water saturation of rock and the interface polarization frequency change rate; Based on the relationship between the complex resistivity of the rock and the interface polarization frequency and the expression for the rate of change of the interface polarization frequency, a water saturation interpretation model is constructed.

4. The water saturation evaluation method according to claim 3, characterized in that: The relationship between the complex resistivity of rock and the interface polarization frequency is established, including: Collect rock samples and conduct electrical spectrum measurement experiments on rock samples; The influence of rock water saturation on interface polarization frequency is analyzed, and the relationship between rock complex resistivity and interface polarization frequency is established.

5. The water saturation prediction method according to claim 3, characterized in that: The relationship between the complex resistivity of the rock and the interface polarization frequency is as follows: Where f0 represents the interfacial polarization frequency when the rock is fully hydrated, f t represents the interfacial polarization frequency when the rock contains oil, R0 represents the complex resistivity when the rock contains complete water, and R t Indicates the complex resistivity of rock containing oil, A f , B f Represents a constant.

6. The water saturation prediction method according to claim 3, characterized in that: The expression of the interface polarization frequency change rate is as follows: Among them, I f represents the rate of change of interface polarization frequency, f t represents the interfacial polarization frequency when the rock contains oil, f0 represents the interfacial polarization frequency when the rock contains complete water, S w represents the water saturation of rock, n' represents the dielectric saturation index similar to the saturation index, and b' represents the coefficient.

7. A water saturation prediction device, characterized in that: include: An acquisition module, used to acquire the interface polarization frequency when the rock is completely water-containing and the interface polarization frequency when the rock is oil-containing; A prediction module is used to predict the water saturation of rocks using a pre-built water saturation interpretation model; The water saturation interpretation model characterizes the relationship between the interface polarization frequency when the rock is completely water-containing, the interface polarization frequency when the rock is oil-containing, and the water saturation of the rock.

8. The water saturation prediction device according to claim 7, characterized in that: The water saturation interpretation model is as follows: Among them, S w Indicates the water saturation of rock, A f , B f represents a constant, n' represents a dielectric saturation index similar to the saturation index, b' represents a coefficient, f0 represents the interfacial polarization frequency when the rock is fully water-containing, and f t Represents the interfacial polarization frequency when the rock contains oil.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by at least one processor, the method according to any one of claims 1 to 6 is implemented.

10. An electronic device, characterized in that: The method comprises a memory and at least one processor, wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method according to any one of claims 1 to 6 is implemented.

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