A method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations

Abstract

The present invention discloses a method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations. The method of the present invention involves collecting deep carbonate rock samples in the work area, obtaining the relationship between the difference in dynamic and static elastic moduli of the rock samples and porosity through petrophysical experiments, constructing a conversion model for the difference in dynamic and static elastic moduli for different porosities, and then combining the logging data of the work area to obtain the total porosity, primary porosity, secondary porosity, and porosity ratio at each depth of the formation. After calculating the porosity nodes of the formation, based on the dynamic elastic modulus curve of the carbonate rock formation, and combining the porosity nodes to correct the dynamic elastic modulus at each depth point of the carbonate rock formation, a static elastic modulus curve of the corrected carbonate rock formation is obtained. The present invention improves the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations, realizes the accurate acquisition of static Young's modulus, and lays a foundation for the reservoir evaluation and exploration and development of deep carbonate rocks.

Description

Technical Field

[0001] The present invention relates to the technical field of logging in carbonate reservoirs, and particularly relates to a method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate formations. Background Art

[0002] Basic rock mechanics parameters such as elastic modulus and Poisson's ratio play important roles in drilling, hydraulic fracturing, and underground engineering. The accurate measurement of basic rock mechanics parameters is the basis for petroleum engineering exploration and development design. According to the test methods, rock mechanics parameters are divided into dynamic parameters and static parameters. The dynamic parameters are determined by measuring the density of the rock sample and the time differences of longitudinal and transverse waves. Among them, the dynamic elastic modulus E D is expressed as:

[0003]

[0004] In the formula, ρ b is the density of the rock sample, with the unit of g / cm 3 ; Δt s is the shear wave time difference, with the unit of s / m; Δt p is the compressional wave time difference, with the unit of s / m, and is obtained by calculating according to actual logging data.

[0005] The static elastic modulus is obtained by testing the relationship between rock stress and strain. The ratio of stress to strain within the elastic deformation range of the rock sample is defined as the static elastic modulus. In the experiment, the static elastic modulus E S is expressed as:

[0006]

[0007] In the formula, (σ 1 -σ 2 ) 50 is 50% of the difference in the maximum principal stress of the rock sample, with the unit of MPa; ε h50 is the strain at the corresponding time point, with the unit of MPa.

[0008] The experimental measurement of the dynamic elastic modulus has the advantages of less time, low cost, and strong practicability. The experimental measurement of the static elastic modulus has a long cycle, high cost but high accuracy, and the experimental measurement process of the static elastic modulus fully considers the underground occurrence state of the rock and the characteristics of petroleum exploration and development, and is more in line with the requirements of petroleum engineering.

[0009] Therefore, in order to facilitate construction measurement and reduce measurement costs, during the actual exploration process, usually, the conversion relationship between dynamic and static parameters is obtained through indoor rock physics experiments, and then logging data is introduced to obtain continuous dynamic parameters, so as to obtain the static parameters required for the project.

[0010] However, at present, the research on the conversion relationship between dynamic and static parameters of rocks mainly focuses on rocks with good physical properties such as sandstone and mud shale. A large number of experimental data show that such rocks generally have a good linear dynamic-static conversion relationship, and the linear fitting degree of dynamic-static conversion is mostly above 0.85. However, the geological environment of deep carbonate rock reservoirs is complex. Under the conditions of "high temperature, high pressure, high salinity and disturbance", the fractures, karst caves and complex pore structures developed in them have a significant impact on dynamic and static parameters, and the nonlinear mechanical phenomena are obvious, resulting in a very low accuracy of the dynamic-static parameter conversion model, which cannot meet the actual production needs and greatly affects the efficient exploration and development of reservoirs. Summary of the Invention

[0011] Aiming at the problem of the insufficient accuracy of the dynamic-static elastic modulus conversion model for deep carbonate rock formations at the present stage, based on the triple porosity logging data and the pore structure characteristics of carbonate rocks, the present invention proposes a method for improving the conversion accuracy of dynamic-static Young's modulus of deep carbonate rock formations. By combining the microscopic pore morphology of carbonate rocks with the actual logging data, the conversion accuracy of the static Young's modulus of deep carbonate rock formations is improved, laying a foundation for the exploration and development of oil and gas in deep carbonate rocks.

[0012] The present invention adopts the following technical solutions:

[0013] A method for improving the conversion accuracy of dynamic-static Young's modulus of deep carbonate rock formations, specifically including the following steps:

[0014] Step 1: Obtain deep carbonate rock samples in the target work area, conduct rock physics experiments by restoring the formation environment where the carbonate rock samples are located, obtain the relationship between the difference in dynamic-static elastic modulus and porosity of the carbonate rock samples, and construct the conversion model M of the dynamic-static elastic modulus difference with large porosity 1 and the conversion model M of the dynamic-static elastic modulus difference with small porosity 2 ;

[0015] Step 2: According to the logging data of the target work area, calculate the total porosity φ t , primary porosity φ p , secondary porosity φ s and porosity ratio P tp at each depth point of the carbonate rock formation, and obtain the total porosity curve, primary porosity curve, secondary porosity curve and porosity ratio curve of the carbonate rock formation;

[0016] Step 3: Determine the first porosity node φ 1 and the second porosity node φ 2 of the carbonate rock formation according to the logging data of the target work area;

[0017] Step 4: Calculate the dynamic elastic modulus curve of the carbonate rock formation using the logging data of the target work area. Combine the total porosity at each depth point of the carbonate rock formation. According to the first porosity node φ 1 and the second porosity node φ 2 correct the dynamic elastic modulus at each depth point of the carbonate rock formation, determine the static elastic modulus at each depth point of the corrected carbonate rock formation, and obtain the static elastic modulus curve of the corrected carbonate rock formation.

[0018] Preferably, in step 1, the following steps are specifically included:

[0019] Step 1.1: Obtain deep carbonate rock samples in the target work area. According to the temperature and pressure of the formation where the deep carbonate rock samples are located, restore the formation environment where the deep carbonate rock samples are located and conduct triaxial rock mechanics experiments. Use the triaxial rock mechanics experiments to measure the dynamic elastic modulus E D , static elastic modulus E S and porosity φ of the deep carbonate rock samples, calculate the difference between the dynamic elastic modulus E D and the static elastic modulus E S to obtain the dynamic-static elastic modulus difference, and determine the functional relationship E D-S (φ) between the dynamic-static elastic modulus difference and the porosity;

[0020] Step 1.2: Fit the functional relationship E D-S (φ) between the dynamic-static elastic modulus difference and the porosity to obtain a fitting curve. According to the fitting curve, divide the porosity of the deep carbonate rock samples into large porosity, medium porosity and small porosity. Use the least squares method to fit the dynamic-static elastic modulus differences corresponding to the large porosity and the dynamic-static elastic modulus differences corresponding to the small porosity respectively, and determine the large porosity dynamic-static elastic modulus difference conversion model M 1 and the dynamic-static elastic modulus difference conversion model M 2 .

[0021] Preferably, in the fitting curve of the functional relationship E D-S (φ) between the dynamic-static elastic modulus difference and the porosity, the relationship between the dynamic-static elastic modulus difference and the porosity in the fitting curves corresponding to the large porosity and the small porosity is linear, and the relationship between the dynamic-static elastic modulus difference and the porosity in the fitting curve corresponding to the medium porosity is non-linear.

[0022] Preferably, in step 2, the following steps are specifically included:

[0023] Step 2.1: Obtain the logging data of the target work area, including neutron logging curve, density logging curve and acoustic travel time logging curve;

[0024] Step 2.2: Calculate the total porosity φ at each depth point of the carbonate rock formation using the neutron logging curve and the density logging curve t , and then calculate the primary porosity φ at each depth point of the carbonate rock formation using the acoustic transit time logging curve p . And based on the total porosity φ t and the primary porosity φ p at each depth point of the carbonate rock formation, calculate the secondary porosity φ s at each depth point of the carbonate rock formation, as shown in formula (1):

[0025] φ s = φ t - φ p (1)

[0026] In the formula, φ s is the secondary porosity of the carbonate rock formation, φ t is the total porosity of the carbonate rock formation, and φ p is the primary porosity of the carbonate rock formation;

[0027] Based on the secondary porosity φ s and the total porosity φ t at each depth point of the carbonate rock formation, calculate the porosity ratio at each depth point of the carbonate rock formation, as shown in formula (2):

[0028]

[0029] In the formula, P tp is the porosity ratio of the carbonate rock formation;

[0030] Step 2.3: Based on the total porosity φ t , primary porosity φ p , secondary porosity φ s and porosity ratio P tp at each depth point of the carbonate rock formation, obtain the total porosity curve, primary porosity curve, secondary porosity curve and porosity ratio curve of the carbonate rock formation

[0031] Preferably, in step 3, according to the neutron logging curve, density logging curve and acoustic transit time logging curve of the target work area, calculate the average primary porosity and average secondary porosity of the carbonate rock formation, and determine the first porosity node and the second porosity node of the carbonate rock formation as follows:

[0032] φ 1 = φ p′ + aφ s′ (3)

[0033] φ 2 = bφp′ +φ s′ (4)

[0034] In the formula, φ 1 is the first porosity node of the carbonate rock formation, φ 2 is the second porosity node of the carbonate rock formation, φ p′ is the average primary porosity of the carbonate rock formation, φ s′ is the average secondary porosity of the carbonate rock formation, and a and b are both dimensionless coefficients.

[0035] Preferably, in the said step 4, it specifically includes the following steps:

[0036] Step 4.1, according to the acoustic time difference logging curve of the target work area, calculate the dynamic elastic modulus values at each depth point of the carbonate rock formation to obtain the dynamic elastic modulus curve of the carbonate rock formation. Combining with the total porosity curve of the carbonate rock formation determined in step 2, based on the first porosity node φ 1 and the second porosity node φ 2 of the carbonate rock formation, correct the dynamic elastic modulus at each depth point of the carbonate rock formation;

[0037] When the total porosity φ t of the carbonate rock formation at the depth point is less than the first porosity node φ 1 , then based on the large porosity dynamic-static elastic modulus difference conversion model M 1 calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value;

[0038] When the total porosity φ t of the carbonate rock formation at the depth point is greater than the first porosity node φ 2 , then based on the small porosity dynamic-static elastic modulus difference conversion model M 2 calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value;

[0039] Otherwise, go to step 4.2;

[0040] Step 4.2, correct the dynamic elastic modulus of the carbonate rock formation according to the porosity ratio P tp of the carbonate rock formation and the preset correction coefficient c;

[0041] When the porosity ratio P tp of the carbonate rock formation at the depth point is not less than the preset correction coefficient c, then based on the small porosity dynamic-static elastic modulus difference conversion model M2 Calculate the difference between the dynamic and static elastic moduli of the carbonate rock formation, and then subtract the difference between the dynamic and static elastic moduli from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value;

[0042] When the porosity ratio of the carbonate rock formation at the depth point is less than the preset correction coefficient c, then based on the large-porosity dynamic-static elastic modulus difference conversion model M 1 Calculate the difference between the dynamic and static elastic moduli of the carbonate rock formation, and then subtract the difference between the dynamic and static elastic moduli from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value;

[0043] Step 4.3, according to the corrected static elastic modulus values at each depth point, obtain the static elastic modulus curve of the corrected carbonate rock formation.

[0044] Preferably, in the step 4.2, the correction coefficient c is determined according to the microscopic pore morphology of the deep carbonate rock samples and is a dimensionless constant between 0 and 1.

[0045] The present invention has the following beneficial effects:

[0046] The method of the present invention is based on the rock mechanics experimental results and microscopic structure of deep carbonate rock samples, comprehensively considers the characteristics of well-developed secondary pores in carbonate reservoirs, combines the three-porosity logging curves to obtain the pore structure parameters of deep carbonate reservoirs, and proposes a method to improve the conversion accuracy of dynamic and static Young's moduli of deep carbonate rock formations, solving the problem of poor conversion accuracy between the dynamic elastic model and the static elastic modulus of deep carbonate reservoirs, and has important significance for guiding the mutual conversion of dynamic and static moduli in actual production.

[0047] The present invention obtains the required parameters for the dynamic-static elastic modulus difference conversion model of the carbonate rock formation according to the actual logging data, ensures the accuracy of the present invention for improving the conversion accuracy of dynamic and static Young's moduli of deep carbonate rock formations, realizes the accurate acquisition of the static elastic modulus of deep carbonate rock formations, and lays a foundation for the reservoir evaluation and exploration and development of deep carbonate rocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a flowchart of a method for improving the conversion accuracy of dynamic and static Young's moduli of deep carbonate rock formations.

[0049] Figure 2 It is a dynamic-static Young's modulus conversion model constructed in the laboratory.

[0050] Figure 3 It is a function relationship curve between the dynamic-static elastic modulus difference of carbonate rock cores and porosity.

[0051] Figure 4It is a logging curve of carbonate rock formation. In the figure, it includes the neutron logging curve, density logging curve and acoustic travel time logging curve of carbonate rock formation. Detailed implementation manners

[0052] Taking a deep carbonate rock formation and the accompanying drawings as an example, the detailed implementation manners of the present invention will be further described as follows:

[0053] The present invention provides a method for improving the conversion accuracy of dynamic and static Young's moduli of deep carbonate rock formations, as Figure 1 shown, which specifically includes the following steps:

[0054] Step 1: Taking Well A in a certain carbonate rock block as an example in this embodiment, 22 carbonate rock cores were collected in Well A for rock physics experiments. The carbonate rock cores are standard cores with a length of 250 mm. The formation environment (including formation temperature and pressure) where each carbonate rock core is located was restored in the laboratory for rock physics experiments, and the porosity, dynamic elastic modulus and static elastic modulus of each carbonate rock core were measured. The measurement results of the porosity, dynamic elastic modulus and static elastic modulus of the carbonate rock cores are shown in Table 1.

[0055] Table 1 Summary table of conversion correction parameters for dynamic and static elastic moduli of carbonate rock cores

[0056]

[0057] Based on the porosity, dynamic elastic modulus and static elastic modulus measured in the laboratory, a conversion model for dynamic and static Young's moduli of carbonate rock cores was constructed, as Figure 2 shown. It can be seen from Figure 2 that the conversion relationship of the conversion model for dynamic and static Young's moduli of carbonate rock cores constructed in the laboratory is poor. Using the least squares method, a polynomial fitting was performed on the difference between the dynamic and static elastic moduli of carbonate rock cores and the porosity, and the functional relationship E D-S (φ) between the difference in dynamic and static elastic moduli of carbonate rock cores and the porosity was obtained, as shown in formula (5):

[0058] E D-S (φ) = E D - E S = 12.273φ 3 - 30.389φ 2 - 15.573φ + 81.295 (5)

[0059] In the formula, E D is the dynamic elastic modulus, E S is the static elastic modulus, and φ is the porosity.

[0060] Based on the functional relationship E between the difference in dynamic and static elastic moduli of carbonate rock cores and the porosityD-S (φ) is fitted to obtain a fitting curve, as Figure 3 shown. According to the fitting relationship of the fitting curve, the porosity of carbonate rock samples is divided into large porosity, medium porosity, and small porosity (the value of large porosity is greater than 2%, and the value of small porosity is less than 2%). Among them, there is a linear relationship between the difference in dynamic and static elastic moduli and porosity in the fitting curves corresponding to large porosity and small porosity, and there is no linear relationship between the difference in dynamic and static elastic moduli and porosity in the fitting curve corresponding to medium porosity.

[0061] In this embodiment, the carbonate rock cores are divided into three groups according to porosity, namely the small porosity group, the medium porosity group, and the large porosity group. Among them, the porosity of the carbonate rock cores in the small porosity group is less than 1.25%, the porosity of the carbonate rock cores in the medium porosity group is 1.25% - 2.25%, and the porosity of the carbonate rock cores in the large porosity group is greater than 2.25%. By further analyzing the pore structures of the carbonate rock cores in the small porosity group, the medium porosity group, and the large porosity group, it is found that the pore morphology of the carbonate rock cores in the small porosity group is mainly primary matrix pores and smaller dissolution pores, and the pore morphology of the carbonate rock cores in the medium porosity group includes fractures, karst caves, matrix pores, dissolution pores, etc. Moreover, there is a good linear relationship between the difference in dynamic and static elastic moduli and porosity of the carbonate rock cores in the small porosity group and the large porosity group, while there is no obvious relationship between the difference in dynamic and static elastic moduli and porosity of the carbonate rock cores in the medium porosity group.

[0062] The difference in dynamic and static elastic moduli and porosity of the carbonate rock cores in the large porosity group are respectively fitted by the least squares method to obtain the large porosity dynamic-static elastic modulus difference conversion model M 1 , and then the difference in dynamic and static elastic moduli and porosity of the carbonate rock cores in the small porosity group are fitted to obtain the small porosity dynamic-static elastic modulus difference conversion model M 2 . The large porosity dynamic-static elastic modulus difference conversion model M 1 and the small porosity dynamic-static elastic modulus difference conversion model M 2 are as follows:

[0063]

[0064] In the formula, M 1 is the large porosity dynamic-static elastic modulus difference conversion model, and M 2 is the small porosity dynamic-static elastic modulus difference conversion model.

[0065] Step 2, obtain the logging data of the target work area, as Figure 4 shown. The logging data of the target work area includes neutron logging curves, density logging curves, and acoustic travel time logging curves. Calculate the total porosity φ at each depth point of the carbonate rock formationt , the original porosity φ p , the secondary porosity φ s and the porosity ratio P tp , to obtain the total porosity curve, original porosity curve, secondary porosity curve and porosity ratio curve of the carbonate rock formation.

[0066] Step 3, according to the neutron log curve, density log curve and acoustic travel time log curve in the logging data of the target work area, calculate the average original porosity and average secondary porosity of the carbonate rock formation, and determine the first porosity node and the second porosity node of the carbonate rock formation as:

[0067] φ 1 = φ p′ + aφ s′ (3)

[0068] φ 2 = bφ p′ + φ s′ (4)

[0069] In the formula, φ 1 is the first porosity node of the carbonate rock formation, φ 2 is the second porosity node of the carbonate rock formation, φ p′ is the average original porosity of the carbonate rock formation, φ s′ is the average secondary porosity of the carbonate rock formation, and both a and b are dimensionless coefficients, which are determined by the rock mechanics experiment of the carbonate rock core and the logging data of the target work area. In this embodiment, a = 0.643 and b = 1.39.

[0070] In this embodiment, the calculated average original porosity of the carbonate rock formation is 0.74% and the average secondary porosity is 1.22%. According to the logging data of the target work area, combined with the microscopic pore analysis of the carbonate rock core and the results of the rock mechanics experiment, the correction coefficient c is preset to 1.74%.

[0071] Step 4, Step 4, calculate the dynamic elastic modulus curve of the carbonate rock formation by using the logging data of the target work area. Combine the total porosity at each depth point of the carbonate rock formation. According to the first porosity node φ 1 and the second porosity node φ 2 of the carbonate rock formation, correct the dynamic elastic modulus at each depth point of the carbonate rock formation, and determine the static elastic modulus at each depth point of the corrected carbonate rock formation to obtain the static elastic modulus curve of the corrected carbonate rock formation, which specifically includes the following steps:

[0072] Step 4.1, based on the acoustic travel-time log curve of the target work area, calculate the dynamic elastic modulus values at each depth point of the carbonate rock formation to obtain the dynamic elastic modulus curve of the carbonate rock formation. Combining with the total porosity curve of the carbonate rock formation, based on the first porosity node φ 1 and the second porosity node φ 2 correct the dynamic elastic modulus at each depth point of the carbonate rock formation.

[0073] When the total porosity φ t of the carbonate rock formation at a depth point is less than the first porosity node φ 1 , then based on the large-porosity dynamic-static elastic modulus difference conversion model M 1 calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value;

[0074] When the total porosity φ t of the carbonate rock formation at a depth point is greater than the first porosity node φ 2 , then based on the small-porosity dynamic-static elastic modulus difference conversion model M 2 calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value;

[0075] Otherwise, go to Step 4.2.

[0076] Step 4.2, based on the porosity ratio P tp of the carbonate rock formation and the preset correction coefficient c, correct the dynamic elastic modulus of the carbonate rock formation.

[0077] When the porosity ratio P tp of the carbonate rock formation at a depth point is not less than the preset correction coefficient c, then based on the small-porosity dynamic-static elastic modulus difference conversion model M 2 calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value;

[0078] When the porosity ratio of the carbonate rock formation at a depth point is less than the preset correction coefficient c, then based on the large-porosity dynamic-static elastic modulus difference conversion model M 1 calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value.

[0079] Step 4.3: Obtain the static elastic modulus curve of the corrected carbonate rock formation based on the corrected static elastic modulus values at each depth point.

[0080] The static elastic moduli of the corrected carbonate rock formation are summarized in Table 1. It can be seen from Table 1 that, compared with the traditional linear conversion method, the sum of squared residuals of the static elastic modulus obtained by segmentally correcting according to the porosity of the carbonate rock formation using the method of the present invention is reduced from 1716.14 to 455.05, and the accuracy of the static elastic modulus is greatly improved. At the same time, the goodness of fit is also increased from 0.241 to 0.797, which is closer to the required goodness of fit of 0.8 in general engineering. Thus, it is obtained that the method of the present invention improves the accuracy of the dynamic-static Young's modulus conversion of deep carbonate rocks, realizes the accurate acquisition of the static elastic modulus of the carbonate rock formation, and lays a foundation for the reservoir evaluation, exploration and development of deep carbonate rocks.

[0081] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the substantial scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations, characterized in that, it specifically includes the following steps: Step 1: Obtain deep carbonate rock samples from the target work area. Conduct rock physics experiments by restoring the formation environment where the carbonate rock samples are located, obtain the relationship between the difference in dynamic and static elastic moduli and porosity of the carbonate rock samples, and construct the conversion model M for the difference in dynamic and static elastic moduli with large porosity 1 and the conversion model M for the difference in dynamic and static elastic moduli with small porosity 2 ; Step 2: According to the logging data of the target work area, calculate the total porosity φ, primary porosity φ, secondary porosity φ and porosity ratio P at each depth point of the carbonate rock formation, and obtain the total porosity curve, primary porosity curve, secondary porosity curve and porosity ratio curve of the carbonate rock formation; t , primary porosity φ p , secondary porosity φ s and porosity ratio P tp ; Step 3, determine the first porosity node φ 1 and the second porosity node φ 2 ; Step 4: Calculate the dynamic elastic modulus curve of the carbonate rock formation using the logging data of the target work area. Combine the total porosity at each depth point of the carbonate rock formation. According to the first porosity node φ 1 and the second porosity node φ 2 correct the dynamic elastic modulus at each depth point of the carbonate rock formation, determine the static elastic modulus at each depth point of the corrected carbonate rock formation, and obtain the static elastic modulus curve of the corrected carbonate rock formation; In the said step 4, it specifically includes the following steps: Step 4.1, calculate the dynamic elastic modulus values at each depth point of the carbonate rock formation according to the acoustic time difference logging curve of the target work area, obtain the dynamic elastic modulus curve of the carbonate rock formation, and combine with the total porosity curve of the carbonate rock formation determined in Step 2. Based on the first porosity node φ 1 and the second porosity node φ 2 correct the dynamic elastic modulus at each depth point of the carbonate rock formation; When the total porosity φ of the carbonate rock formation at the depth point t is less than the first porosity node φ 1 , then based on the large porosity dynamic-static elastic modulus difference conversion model M 1 calculate the difference between the dynamic and static elastic moduli of the carbonate rock formation, and then subtract the difference between the dynamic and static elastic moduli from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value; When the total porosity φ of the carbonate formation at the depth point t is greater than the first porosity node φ 2 then, based on the small porosity dynamic-static elastic modulus difference conversion model M 2 calculate the difference between the dynamic and static elastic moduli of the carbonate formation, and then subtract the difference between the dynamic and static elastic moduli from the dynamic elastic modulus value of the carbonate formation to obtain the corrected static elastic modulus value; Otherwise, go to step 4.2; Step 4.2, correct the dynamic elastic modulus of the carbonate rock formation according to the porosity ratio P of the carbonate rock formation tp and the preset correction coefficient c; When the porosity ratio P of the carbonate rock formation at the depth point tp is not less than the preset correction coefficient c, then based on the small porosity dynamic-static elastic modulus difference conversion model M 2 calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value; When the porosity ratio of the carbonate rock formation at the depth point is less than the preset correction coefficient c, then based on the large porosity dynamic-static elastic modulus difference conversion model M 1 Calculate the dynamic-static elastic modulus difference of the carbonate rock formation, and then subtract the dynamic-static elastic modulus difference from the dynamic elastic modulus value of the carbonate rock formation to obtain the corrected static elastic modulus value; Step 4.3, according to the corrected static elastic modulus values at each depth point, obtain the static elastic modulus curve of the corrected carbonate rock formation.

2. The method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations according to claim 1, characterized in that, in the said step 1, it specifically includes the following steps: Step 1.1, obtain deep carbonate rock samples in the target work area. According to the temperature and pressure of the strata where the deep carbonate rock samples are located, restore the formation environment where the deep carbonate rock samples are located and conduct triaxial rock mechanics experiments. Use the triaxial rock mechanics experiments to measure the dynamic elastic modulus E D , static elastic modulus E S and porosity φ, calculate the difference between the dynamic elastic modulus E D and the static elastic modulus E S to obtain the dynamic-static elastic modulus difference, and determine the functional relationship E D-S (φ); Step 1.

2. By fitting the functional relationship E D-S (φ) between the difference in dynamic and static elastic moduli and porosity to obtain a fitting curve, the porosity of deep carbonate rock samples is divided into large porosity, medium porosity, and small porosity according to the fitting curve. The least squares method is used to fit the difference in dynamic and static elastic moduli corresponding to large porosity and the difference in dynamic and static elastic moduli corresponding to small porosity respectively, and the conversion model M 1 of the difference in dynamic and static elastic moduli and the conversion model M 2 are determined.

3. The method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations according to claim 2, characterized in that, The functional relationship E D-S between the difference in dynamic and static elastic moduli and porosity in the fitting curve (φ): In the fitting curves corresponding to large porosities and small porosities, there is a linear relationship between the difference in dynamic and static elastic moduli and porosity, while in the fitting curve corresponding to medium porosities, there is no linear relationship between the difference in dynamic and static elastic moduli and porosity.

4. The method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations according to claim 2, characterized in that, in the said step 2, it specifically includes the following steps: Step 2.1, obtain the logging data of the target work area, including neutron logging curve, density logging curve and acoustic travel time logging curve; Step 2.2, calculate the total porosity φ at each depth point of the carbonate rock formation using the neutron log curve and the density log curve t , then calculate the primary porosity φ at each depth point of the carbonate rock formation using the acoustic travel time log curve p , and based on the total porosity φ at each depth point of the carbonate rock formation t and the primary porosity φ p , calculate the secondary porosity φ at each depth point of the carbonate rock formation s , as shown in formula (1): φ s = φ t - φ p (1) where φ s is the secondary porosity of the carbonate formation, φ t is the total porosity of the carbonate formation, and φ p is the primary porosity of the carbonate formation; According to the secondary porosity φ at each depth point of the carbonate rock formation s and the total porosity φ t , calculate the porosity ratio at each depth point of the carbonate rock formation as shown in formula (2): Wherein, P tp is the porosity ratio of carbonate rock formations; Step 2.3, based on the total porosity φ, primary porosity φ, secondary porosity φ, and porosity ratio P at each depth point of the carbonate rock formation t , primary porosity φ p , secondary porosity φ s and porosity ratio P tp , the total porosity curve, primary porosity curve, secondary porosity curve, and porosity ratio curve of the carbonate rock formation are obtained.

5. The method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations according to claim 4, characterized in that, in the said step 3, according to the neutron logging curve, density logging curve and acoustic travel time logging curve of the target work area, calculate the average primary porosity and average secondary porosity of the carbonate rock formation, and determine the first porosity node and the second porosity node of the carbonate rock formation as: φ 1 = φp ′ + aφs ′ (3) φ 2 = bφp ′ + φs ′ (4) Where φ 1 is the first porosity node of the carbonate rock formation, φ 2 is the second porosity node of the carbonate rock formation, φ p′ is the average primary porosity of the carbonate rock formation, φ s′ is the average secondary porosity of the carbonate rock formation, and a and b are both dimensionless coefficients.

6. The method for improving the conversion accuracy of dynamic and static Young's moduli in deep carbonate rock formations according to claim 1, characterized in that, in the said step 4.2, the correction coefficient c is determined according to the microscopic pore morphology of deep carbonate rock samples, and is a dimensionless constant between 0 and 1.

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