Method and device for predicting effective porosity of tight sandstone reservoir
By determining the correspondence between effective porosity and Young's modulus in dense sandstone reservoirs, and calculating Young's modulus in combination with Poisson's ratio and volumetric modulus attributes, the problem of inaccurate prediction of effective porosity in dense sandstone reservoirs in the existing technology is solved, and the precise prediction and development support of the reservoir are achieved.
Patent Information
- Application Number
- CN202311355411.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-18
- Publication Date
- 2025-04-18
AI Technical Summary
In the prior art, when fitting the effective porosity of the dense sandstone reservoir based on logging data and core data, the characteristic points are scattered, resulting in inaccurate prediction results and unable to effectively support the development of the dense sandstone reservoir.
By determining the correspondence between the effective porosity and Young's modulus at multiple depth points in a dense sandstone reservoir, and using the Poisson's ratio and volumetric modulus attribute bodies, the effective porosity attribute bodies of the entire reservoir are predicted.
Accurate prediction of effective porosity of tight sandstone reservoirs has been achieved, providing technical support for the development of tight sandstone reservoirs.
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of oil and gas extraction, and in particular to a method and device for predicting the effective porosity of a tight sandstone reservoir. Background Art
[0002] At present, my country's tight sandstone reservoir resources are abundant and widely distributed. The oil and gas reservoirs in many tight sandstone areas have huge reserves. Therefore, it is particularly important to predict the effective porosity of tight sandstone reservoirs and then determine the storage performance of tight sandstone reservoirs to provide technical support for the development of tight sandstone reservoirs.
[0003] In the related art, the method for predicting the effective porosity of tight sandstone reservoirs is usually to determine the correspondence between the logging characteristics and the effective porosity after fitting the logging characteristic curve (such as the natural potential curve, resistivity curve or acoustic time difference curve) obtained based on the logging data and the effective porosity data obtained based on the core measurement, and then determine the effective porosity of the target tight sandstone reservoir based on the corresponding relationship and the logging characteristic curve of the target tight sandstone reservoir.
[0004] However, when fitting the logging characteristic curve obtained based on the logging data and the effective porosity data obtained based on the core measurement in the related technology, the characteristic points are distributed in a scattered manner, which makes the effective porosity value predicted based on the correspondence between the logging characteristics and the effective porosity inaccurate, and cannot provide technical support for the development of tight sandstone reservoirs. Summary of the invention
[0005] In view of this, the present application provides a method and device for predicting the effective porosity of tight sandstone reservoirs, which achieves accurate prediction of the effective porosity of tight sandstone and provides technical support for the development of tight sandstone reservoirs.
[0006] Specifically, the following technical solutions are included:
[0007] On the one hand, an embodiment of the present application provides a method for predicting the effective porosity of a tight sandstone reservoir, the method comprising:
[0008] According to the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir, the corresponding relationship between the effective porosity and Young's modulus is determined;
[0009] Obtaining a Young's modulus attribute body of the target tight sandstone reservoir according to a Poisson's ratio attribute body and a bulk modulus attribute body of the target tight sandstone reservoir, wherein each data point in the Poisson's ratio attribute body and the bulk modulus attribute body corresponds one to one;
[0010] Based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir, an effective porosity attribute of the target tight sandstone reservoir is obtained.
[0011] In some embodiments, determining the corresponding relationship between the effective porosity and the Young's modulus at multiple depth points in the target tight sandstone reservoir comprises:
[0012] A two-dimensional coordinate system is established with Young's modulus as the horizontal axis and effective porosity as the vertical axis;
[0013] Based on the two-dimensional coordinate system, the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir are fitted to obtain the corresponding relationship between the effective porosity and Young's modulus.
[0014] In some embodiments, obtaining the Young's modulus attribute of the target tight sandstone reservoir according to the Poisson's ratio attribute and the bulk modulus attribute of the target tight sandstone reservoir comprises:
[0015] Substitute the Poisson's ratio of each data point in the Poisson's ratio attribute body and the bulk modulus of each data point in the bulk modulus attribute body of the target tight sandstone reservoir into the conversion formula to calculate the Young's modulus attribute body of the target tight sandstone reservoir, wherein the conversion formula is:
[0016] E = 3*K(1-2v);
[0017] Wherein, E represents Young's modulus, K represents bulk modulus, and v represents Poisson's ratio.
[0018] In some embodiments, obtaining the effective porosity attribute of the target tight sandstone reservoir based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir includes:
[0019] The Young's modulus of each point in the Young's modulus attribute body of the target tight sandstone reservoir is substituted into the corresponding relationship between the effective porosity and the Young's modulus to obtain the effective porosity attribute body of the target tight sandstone reservoir.
[0020] In some embodiments, after obtaining the effective porosity attribute of the target tight sandstone reservoir based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir, the method further includes:
[0021] The effective porosity attribute volume of the target tight sandstone reservoir is cut to obtain an effective porosity profile, and the effective porosity profile is used to characterize the effective porosity distribution characteristics.
[0022] In some embodiments, before determining the corresponding relationship between the effective porosity and the Young's modulus at multiple depth points in the target tight sandstone reservoir, the method further includes:
[0023] Obtain core and logging data from multiple layers at different depths in the target tight sandstone reservoir;
[0024] Based on the cores of multiple layers at different depths in the target tight sandstone reservoir, the effective porosity at multiple depth points is obtained;
[0025] Based on the XMAC logging curve sequence in the logging data and the effective porosity of the multiple depth points, the Young's modulus of the multiple depth points is obtained.
[0026] In some embodiments, obtaining the Young's modulus of the multiple depth points based on the XMAC logging curve sequence in the logging data and the effective porosity of the multiple depth points includes:
[0027] determining corresponding depths of the plurality of depth points based on the effective porosities of the plurality of depth points;
[0028] The Young's modulus of the corresponding depths of the multiple depth points in the XMAC logging curve sequence is determined as the Young's modulus of the multiple depth points.
[0029] In some embodiments, before obtaining the Young's modulus attribute of the target tight sandstone reservoir according to the Poisson's ratio attribute and the bulk modulus attribute of the target tight sandstone reservoir, the method further comprises:
[0030] Obtain the probability density function of the P-wave and S-wave velocity ratio and rock density of the target tight sandstone reservoir;
[0031] Based on the P-wave velocity ratio and the probability density function of the rock density of the target tight sandstone reservoir, multiple ray elastic impedance curves are obtained;
[0032] Performing interpolation operation on the plurality of ray elastic impedance curves to obtain a ray elastic impedance transition model;
[0033] Inverting the ray elastic impedance transition model to obtain a ray elastic impedance transition inversion model;
[0034] Based on the ray elastic impedance transition inversion model, the Poisson's ratio attribute body and the bulk modulus attribute body are obtained.
[0035] In some embodiments, obtaining the probability density function of the P-wave velocity ratio and the rock density of the target tight sandstone reservoir includes:
[0036] Obtain the P-wave and S-wave velocity ratio curve and rock density curve of the target tight sandstone reservoir;
[0037] The P-wave velocity ratio curve and the rock density curve are fitted to obtain a probability density function of the P-wave velocity ratio and the rock density.
[0038] On the other hand, an embodiment of the present application provides a device for predicting the effective porosity of a tight sandstone reservoir, the device comprising:
[0039] A determination module, for determining a corresponding relationship between effective porosity and Young's modulus according to effective porosity data and Young's modulus data of a target tight sandstone reservoir;
[0040] A first obtaining module is used to obtain a Young's modulus attribute body according to a Poisson's ratio attribute body and a bulk modulus attribute body of a target tight sandstone reservoir;
[0041] The second obtaining module is used to substitute the Young's modulus attribute body into the corresponding relationship between the effective porosity and the Young's modulus to obtain the effective porosity attribute body.
[0042] The beneficial effects of the technical solution provided by the embodiments of the present application include at least:
[0043] The method for predicting the effective porosity of tight sandstone provided in the embodiment of the present application uses the effective porosity and Young's modulus of multiple depth points in the target tight sandstone reservoir to determine the corresponding relationship between the effective porosity and the Young's modulus, and then substitutes the corresponding relationship into the Young's modulus attribute body determined by the Poisson's ratio attribute body and the bulk modulus attribute body of the target tight sandstone to determine the effective porosity attribute body of the target tight sandstone reservoir, that is, to predict the effective porosity of all data points in the entire target tight sandstone reservoir. This method predicts the effective porosity using the Young's modulus, and since the correlation between the corresponding relationship between the Young's modulus and the effective porosity is strong, it achieves accurate prediction of the effective porosity of tight sandstone, providing technical support for the development of tight sandstone reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS
[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0045] Figure 1 A flow chart of a method for predicting effective porosity of tight sandstone provided in an embodiment of the present application;
[0046] Figure 2 A flow chart of another method for predicting effective porosity of tight sandstone provided in an embodiment of the present application;
[0047] Figure 3 A flow chart of obtaining Young's modulus at multiple depth points based on an XMAC logging curve sequence in logging data and effective porosity at multiple depth points in a method for predicting effective porosity of tight sandstone provided in an embodiment of the present application;
[0048] Figure 4 A flow chart for determining the corresponding relationship between effective porosity and Young's modulus according to effective porosity and Young's modulus at multiple depth points in a target tight sandstone reservoir in a method for predicting effective porosity of tight sandstone provided in an embodiment of the present application;
[0049] Figure 5 A schematic diagram of the corresponding relationship between effective porosity and Young's modulus provided in an embodiment of the present application;
[0050] Figure 6 A profile diagram showing the distribution characteristics of effective porosity of a target tight sandstone reservoir provided in an embodiment of the present application;
[0051] Figure 7 A schematic diagram of the structure of a device for predicting the effective porosity of a tight sandstone reservoir provided in an embodiment of the present application.
[0052] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION
[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0054] In order to make the technical solutions and advantages of the present application more clear, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.
[0055] At present, my country's tight sandstone reservoir resources are rich and widely distributed. The reserves of oil and gas reservoirs in many tight sandstone areas are huge. Before developing oil and gas reservoirs in tight sandstone areas, it is necessary to measure the reservoir performance of the reservoir. The effective porosity data of the reservoir can intuitively reflect the reservoir performance of the reservoir. Therefore, it is particularly important to predict the effective porosity of tight sandstone reservoirs and then determine the reservoir performance of tight sandstone reservoirs to provide technical support for the development of tight sandstone reservoirs.
[0056] In the related art, the method for predicting the effective porosity of tight sandstone reservoirs is usually to determine the correspondence between the logging characteristics and the effective porosity after fitting the logging characteristic curve (such as the natural potential curve, resistivity curve or acoustic time difference curve) obtained based on the logging data and the effective porosity data measured in the core obtained from the wellbore, and then determine the effective porosity of the target tight sandstone reservoir based on the corresponding relationship and the logging characteristic curve of the target tight sandstone reservoir.
[0057] However, on the one hand, since tight sandstone often presents the characteristics of "mud wrapped in sand", thin thickness and poor physical properties, the characteristic points of the logging characteristic curves obtained based on logging data and the effective porosity data obtained based on core measurement in the relevant technologies are scattered when fitting, which makes the effective porosity predicted based on the correspondence between logging characteristics and effective porosity inaccurate; on the other hand, for areas between wells, no wells and few wells, there is a lack of core samples and logging characteristic curves, and it is also very difficult to predict accurate effective porosity based on the existing correspondence; on the whole, these related technologies cannot provide technical support for the development of tight sandstone reservoirs.
[0058] In order to solve the technical problems existing in the related art, the embodiment of the present application provides a method for predicting the effective porosity of tight sandstone, which can provide technical support for the development of tight sandstone reservoirs.
[0059] Figure 1 A flowchart of a method for predicting the effective porosity of tight sandstone provided in an embodiment of the present application. Figure 1 , the method comprises the following steps:
[0060] Step 101, determining a corresponding relationship between effective porosity and Young's modulus according to effective porosity and Young's modulus at multiple depth points in a target tight sandstone reservoir.
[0061] Step 102 , obtaining a Young's modulus attribute body of the target tight sandstone reservoir according to a Poisson's ratio attribute body and a bulk modulus attribute body of the target tight sandstone reservoir, wherein each data point in the Poisson's ratio attribute body and the bulk modulus attribute body has a one-to-one correspondence.
[0062] Step 103: Based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute body of the target tight sandstone reservoir, an effective porosity attribute body of the target tight sandstone reservoir is obtained.
[0063] The method for predicting the effective porosity of tight sandstone provided in the embodiment of the present application uses the effective porosity and Young's modulus of multiple depth points in the target tight sandstone reservoir to determine the corresponding relationship between the effective porosity and the Young's modulus, and then substitutes the corresponding relationship into the Young's modulus attribute body determined by the Poisson's ratio attribute body and the bulk modulus attribute body of the target tight sandstone to determine the effective porosity attribute body of the target tight sandstone reservoir, that is, to predict the effective porosity of all data points in the entire target tight sandstone reservoir. This method uses Young's modulus to predict the effective porosity. Since the correlation between the corresponding relationship between Young's modulus and effective porosity is strong, it can achieve accurate prediction of the effective porosity of tight sandstone, providing technical support for the development of tight sandstone reservoirs.
[0064] In some embodiments, according to the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir, determining the corresponding relationship between the effective porosity and the Young's modulus includes:
[0065] A two-dimensional coordinate system is established with Young's modulus as the horizontal axis and effective porosity as the vertical axis;
[0066] Based on the two-dimensional coordinate system, the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir are fitted to obtain the corresponding relationship between the effective porosity and Young's modulus.
[0067] In some embodiments, obtaining the Young's modulus attribute of the target tight sandstone reservoir according to the Poisson's ratio attribute and the bulk modulus attribute of the target tight sandstone reservoir includes:
[0068] Substitute the Poisson's ratio of each data point in the Poisson's ratio attribute body of the target tight sandstone reservoir and the bulk modulus of each data point in the bulk modulus attribute body into the conversion formula to calculate the Young's modulus attribute body of the target tight sandstone reservoir, where the conversion formula is:
[0069] E = 3*K(1-2v);
[0070] Wherein, E represents Young's modulus, K represents bulk modulus, and v represents Poisson's ratio.
[0071] In some embodiments, based on the correspondence between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir, obtaining the effective porosity attribute of the target tight sandstone reservoir includes:
[0072] The Young's modulus of each point in the Young's modulus attribute body of the target tight sandstone reservoir is substituted into the corresponding relationship between the effective porosity and the Young's modulus to obtain the effective porosity attribute body of the target tight sandstone reservoir.
[0073] In some embodiments, after obtaining the effective porosity attribute of the target tight sandstone reservoir based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir, the method further includes:
[0074] The effective porosity attribute volume of the target tight sandstone reservoir is cut to obtain an effective porosity profile, which is used to characterize the effective porosity distribution characteristics.
[0075] In some embodiments, before determining the corresponding relationship between the effective porosity and the Young's modulus at multiple depth points in the target tight sandstone reservoir, the method further includes:
[0076] Obtain core and logging data from multiple layers at different depths in the target tight sandstone reservoir;
[0077] Based on the cores of multiple layers at different depths in the target tight sandstone reservoir, the effective porosity at multiple depth points is obtained;
[0078] Based on the XMAC logging curve sequence in the logging data and the effective porosity at multiple depth points, the Young's modulus at multiple depth points is obtained.
[0079] In some embodiments, based on the XMAC logging curve sequence in the logging data and the effective porosity at the multiple depth points, obtaining the Young's modulus at the multiple depth points includes:
[0080] Determining corresponding depths of the plurality of depth points based on effective porosities of the plurality of depth points;
[0081] The Young's modulus of the corresponding depths of the multiple depth points in the XMAC logging curve sequence is determined as the Young's modulus of the multiple depth points.
[0082] In some embodiments, before obtaining the Young's modulus attribute of the target tight sandstone reservoir according to the Poisson's ratio attribute and the bulk modulus attribute of the target tight sandstone reservoir, the method further comprises:
[0083] Obtain the probability density function of the P-wave and S-wave velocity ratio and rock density of the target tight sandstone reservoir;
[0084] Based on the P-wave velocity ratio and the probability density function of the rock density of the target tight sandstone reservoir, multiple ray elastic impedance curves are obtained;
[0085] Interpolation operation is performed on multiple ray elastic impedance curves to obtain a ray elastic impedance transition model;
[0086] Inverting the ray elastic impedance transition model to obtain the ray elastic impedance transition inversion model;
[0087] Based on the ray elastic impedance transition inversion model, the Poisson's ratio attribute body and the bulk modulus attribute body are obtained.
[0088] In some embodiments, obtaining the probability density function of the P-wave velocity ratio and the rock density of the target tight sandstone reservoir includes:
[0089] Obtain the P-wave and S-wave velocity ratio curve and rock density curve of the target tight sandstone reservoir;
[0090] The P-wave velocity ratio curve and the rock density curve are fitted to obtain the probability density function of the P-wave velocity ratio and the rock density.
[0091] Figure 2 A flowchart of another method for predicting the effective porosity of tight sandstone provided in an embodiment of the present application. Figure 2 , the method comprises the following steps:
[0092] Step 201, obtaining core and logging data of multiple layers at different depths in a target tight sandstone reservoir.
[0093] Since the core can reflect the actual geological conditions of the underground reservoir to a certain extent, by obtaining cores of multiple layers at different depths, it is convenient to obtain the effective porosity of multiple depth points in the reservoir based on the cores of multiple layers at different depths. Since the logging data reflects the geological conditions of the production well, by obtaining the logging data, it is convenient to calculate the Young's modulus of multiple depth points.
[0094] It should be noted that in order to ensure that the obtained cores can fully reflect the effective porosity of the target tight sandstone reservoir, it is necessary to drill cores at equal intervals from bottom to top in the development layer of the target tight sandstone to ensure full coverage of the physical properties of the target tight sandstone reservoir.
[0095] Step 202: Based on the cores of multiple layers at different depths in the target tight sandstone reservoir, the effective porosity at multiple depth points is obtained.
[0096] By conducting core mercury injection experiments on cores of multiple layers at different depths in the target tight sandstone reservoir, the effective porosity corresponding to each core can be obtained. In other words, cores of multiple layers at different depths correspond to effective porosities at multiple depth points.
[0097] Step 203, based on the XMAC logging curve sequence in the logging data and the effective porosity at the multiple depth points, obtain the Young's modulus at the multiple depth points.
[0098] See also Figure 3 , step 203 includes the following sub-steps:
[0099] Step 2031, determining corresponding depths of the multiple depth points based on the effective porosity of the multiple depth points.
[0100] In the XMAC logging curve sequence, a point at the same depth as the depth point selected when measuring the effective porosity was selected previously was selected as the reading point of the Young's modulus to ensure that the corresponding relationship between the Young's modulus and the effective porosity can be fitted later.
[0101] Step 2032: determine the Young's modulus of the corresponding depths of the multiple depth points in the XMAC logging curve sequence as the Young's modulus of the multiple depth points.
[0102] In some embodiments, in the XMAC logging curve sequence, the Young's modulus within 0.1 m above and below each depth point is averaged, and the average value is used as the Young's modulus of the depth point, which can effectively reduce the error and improve the accuracy of the measured Young's modulus.
[0103] Step 204: Determine the corresponding relationship between the effective porosity and the Young's modulus according to the effective porosity and the Young's modulus at multiple depth points in the target tight sandstone reservoir.
[0104] By determining the corresponding relationship between the effective porosity and the Young's modulus, it is convenient to obtain the effective porosity attribute body of the target tight sandstone reservoir based on the relationship and the Young's modulus attribute body of the target tight sandstone reservoir.
[0105] It can be understood that each depth point corresponds to effective porosity and Young's modulus, that is, at the same depth point, there are both effective porosity values and Young's modulus values.
[0106] In some embodiments, see Figure 4 , step 204 includes the following sub-steps:
[0107] Step 2041, establish a two-dimensional coordinate system with Young's modulus as the horizontal axis and effective porosity as the vertical axis.
[0108] By establishing a two-dimensional coordinate system with Young's modulus as the horizontal axis and effective porosity as the vertical axis, the effective porosity and Young's modulus of multiple depth points can be more intuitively displayed in the two-dimensional coordinate system.
[0109] Step 2042, based on the two-dimensional coordinate system, the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir are fitted to obtain the corresponding relationship between the effective porosity and the Young's modulus.
[0110] The data in the two-dimensional coordinate system are fitted, and the corresponding relationship between the effective porosity and Young's modulus is expressed by the fitted function based on the principle of maximizing the correlation coefficient.
[0111] For example, when the effective porosity and Young's modulus measured at multiple depth points in the target tight sandstone reservoir are shown in Table 1, the corresponding relationship between the effective porosity and Young's modulus is as follows: Figure 5 As shown in the figure, the functional formula of effective porosity and Young's modulus after fitting is as follows:
[0112] PhitEffective = -1.31722 + 0.643423 * E;
[0113] Among them, Phit effective is the effective porosity of tight sandstone, and E is Young's modulus.
[0114] Table 1 Effective porosity and Young's modulus data of target tight sandstone reservoir
[0115] Depth(m) Effective porosity (%) Young's modulus (Gpa) 3950.1 5.63 11.70 3954.6 7.50 12.74 3955.2 6.25 12.26 3956.3 8.75 16.32 3962.5 4.68 9.43
[0116] from Figure 5 It can be seen that the fitting similarity between effective porosity and Young's modulus is high. Therefore, if the Young's modulus of the target tight sandstone reservoir is known, the effective porosity of the target tight sandstone reservoir can be obtained according to the fitting function formula.
[0117] Step 205 , obtaining a Young's modulus attribute body of the target tight sandstone reservoir according to a Poisson's ratio attribute body and a bulk modulus attribute body of the target tight sandstone reservoir, wherein each data point in the Poisson's ratio attribute body and the bulk modulus attribute body has a one-to-one correspondence.
[0118] According to the Poisson's ratio attribute body and the bulk modulus attribute body of the target tight sandstone reservoir, a Young's modulus attribute body that can reflect the Young's modulus of the entire target tight sandstone reservoir is obtained.
[0119] In some embodiments, step 205 specifically includes: substituting the Poisson's ratio of each data point in the Poisson's ratio attribute body and the bulk modulus of each data point in the bulk modulus attribute body of the target tight sandstone reservoir into a conversion formula to calculate the Young's modulus attribute body of the target tight sandstone reservoir.
[0120] The conversion formula is:
[0121] E = 3*K(1-2v);
[0122] Wherein, E represents Young's modulus, K represents bulk modulus, and v represents Poisson's ratio.
[0123] By substituting each group of data points in the two attribute bodies into the conversion formula, the Young's modulus data of the entire target tight sandstone reservoir is obtained, and then the Young's modulus attribute body of the target tight sandstone reservoir is obtained.
[0124] In some embodiments, the Poisson's ratio attribute and bulk modulus attribute of the target tight sandstone reservoir can be obtained according to the following steps: obtaining the probability density function of the P-wave velocity ratio and the rock density of the target tight sandstone reservoir; obtaining multiple ray elastic impedance curves based on the probability density function of the P-wave velocity ratio and the rock density of the target tight sandstone reservoir; performing interpolation operations on the multiple ray elastic impedance curves to obtain a ray elastic impedance transition model; inverting the ray elastic impedance transition model to obtain a ray elastic impedance transition inversion model; and obtaining the Poisson's ratio attribute and bulk modulus attribute based on the ray elastic impedance transition inversion model.
[0125] Among them, obtaining the probability density function of the P-wave velocity ratio and the rock density of the target tight sandstone reservoir includes: obtaining the P-wave velocity ratio curve and the rock density curve of the target tight sandstone reservoir; fitting the P-wave velocity ratio curve and the rock density curve to obtain the probability density function of the P-wave velocity ratio and the rock density; based on the P-wave velocity ratio and the rock density probability density function of the target tight sandstone reservoir, obtaining multiple ray elastic impedance curves includes: based on the P-wave velocity ratio and the rock density probability density function of the target tight sandstone reservoir, based on the three different angles of the sub-angle superposition seismic data volume obtained by pre-stack time migration seismic data, obtaining multiple ray elastic impedance curves.
[0126] In some embodiments, the acquisition of the Poisson's ratio attribute body and the bulk modulus attribute body of the target tight sandstone reservoir can be achieved by Jason software.
[0127] Step 206: Based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute body of the target tight sandstone reservoir, an effective porosity attribute body of the target tight sandstone reservoir is obtained.
[0128] Substitute the Young's modulus attribute of the target tight sandstone reservoir obtained in step 205 into the corresponding relationship between the effective porosity and the Young's modulus, and then obtain the effective porosity attribute of the target tight sandstone reservoir. Since the corresponding relationship between the Young's modulus and the effective porosity is highly correlated, the effective porosity attribute can accurately predict the effective porosity of the target tight sandstone reservoir, and then accurately reflect the reservoir performance of the entire target tight sandstone reservoir, providing technical support for the development of the tight sandstone reservoir.
[0129] In some embodiments, step 206 specifically includes: substituting the Young's modulus of each point in the Young's modulus attribute body of the target tight sandstone reservoir into the corresponding relationship between effective porosity and Young's modulus to obtain the effective porosity attribute body of the target tight sandstone reservoir.
[0130] By substituting the Young's modulus of each point into the corresponding relationship between effective porosity and Young's modulus, the effective porosity attribute body of the target tight sandstone reservoir is obtained.
[0131] Step 207, cutting the effective porosity attribute volume of the target tight sandstone reservoir to obtain an effective porosity profile, and the effective porosity profile is used to characterize the effective porosity distribution characteristics.
[0132] By cutting the effective porosity attribute volume of the target tight sandstone reservoir at any angle (for example, horizontally or vertically), an effective porosity profile can be obtained, and the effective porosity profile can reflect the distribution characteristics of the effective porosity of the target tight sandstone reservoir.
[0133] For example, Figure 6 A distribution characteristic profile of effective porosity of a target tight sandstone reservoir provided in an embodiment of the present application, see Figure 6 Through this distribution feature, the oil and gas resource storage performance of the target tight sandstone reservoir can be intuitively calculated, providing technical support for the development of tight sandstone reservoirs.
[0134] Therefore, the method for predicting the effective porosity of tight sandstone provided in the embodiment of the present application uses the effective porosity and Young's modulus of multiple depth points in the target tight sandstone reservoir to determine the corresponding relationship between the effective porosity and the Young's modulus, and then substitutes the corresponding relationship into the Young's modulus attribute body determined by the Poisson's ratio attribute body and the bulk modulus attribute body of the target tight sandstone to determine the effective porosity attribute body of the target tight sandstone reservoir, that is, to predict the effective porosity of all data points in the entire target tight sandstone reservoir. This method predicts the effective porosity using Young's modulus, and since the correlation between the corresponding relationship between Young's modulus and effective porosity is strong, it achieves accurate prediction of the effective porosity of tight sandstone, providing technical support for the development of tight sandstone reservoirs.
[0135] Figure 7 A schematic diagram of a device for predicting the effective porosity of a tight sandstone reservoir provided in an embodiment of the present application is shown in FIG. Figure 7 , the device 700 comprises:
[0136] A determination module 701 is used to determine the corresponding relationship between the effective porosity and the Young's modulus according to the effective porosity data and the Young's modulus data of the target tight sandstone reservoir;
[0137] A first obtaining module 702 is used to obtain a Young's modulus attribute body according to a Poisson's ratio attribute body and a bulk modulus attribute body of a target tight sandstone reservoir;
[0138] The second obtaining module 703 is used to substitute the Young's modulus attribute body into the corresponding relationship between the effective porosity and the Young's modulus to obtain the effective porosity attribute body.
[0139] In some embodiments, the determination module 701 includes:
[0140] The system building submodule is used to build a two-dimensional coordinate system with Young's modulus as the horizontal axis and effective porosity as the vertical axis;
[0141] The corresponding relationship determination submodule is used to fit the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir based on a two-dimensional coordinate system to obtain the corresponding relationship between the effective porosity and Young's modulus.
[0142] In some embodiments, the first obtaining module 702 includes:
[0143] The first calculation submodule is used to substitute the Poisson's ratio of each data point in the Poisson's ratio attribute body and the bulk modulus of each data point in the bulk modulus attribute body of the target tight sandstone reservoir into the conversion formula to calculate the Young's modulus attribute body of the target tight sandstone reservoir, wherein the conversion formula is:
[0144] E = 3*K(1-2v);
[0145] Wherein, E represents Young's modulus, K represents bulk modulus, and v represents Poisson's ratio.
[0146] In some embodiments, the second obtaining module 703 includes:
[0147] The second calculation submodule is used to substitute the Young's modulus of each point in the Young's modulus attribute body of the target tight sandstone reservoir into the corresponding relationship between the effective porosity and the Young's modulus to obtain the effective porosity attribute body of the target tight sandstone reservoir.
[0148] In some embodiments, the apparatus 700 further includes:
[0149] The cutting module is used to cut the effective porosity attribute body of the target tight sandstone reservoir to obtain the effective porosity profile, which is used to characterize the effective porosity distribution characteristics.
[0150] In some embodiments, the apparatus 700 further includes:
[0151] The first acquisition module is used to obtain core and logging data of multiple layers at different depths in the target tight sandstone reservoir;
[0152] A third obtaining module is used to obtain effective porosity at multiple depth points based on cores of multiple layers at different depths in the target tight sandstone reservoir;
[0153] The fourth obtaining module is used to obtain the Young's modulus of multiple depth points based on the XMAC logging curve sequence in the logging data and the effective porosity of multiple depth points.
[0154] In some embodiments, the fourth obtaining module includes:
[0155] A first determination submodule is used to determine corresponding depths of the plurality of depth points based on the effective porosity of the plurality of depth points;
[0156] The second determination submodule is used to determine the Young's modulus of the corresponding depths of the multiple depth points in the XMAC logging curve sequence as the Young's modulus of the multiple depth points.
[0157] In some embodiments, the apparatus 700 further includes:
[0158] The second acquisition module is used to obtain the probability density function of the P-wave velocity ratio and the rock density of the target tight sandstone reservoir;
[0159] A fifth obtaining module is used to obtain a plurality of ray elastic impedance curves based on the P-S wave velocity ratio of the target tight sandstone reservoir and the probability density function of the rock density;
[0160] A sixth obtaining module is used to perform interpolation operation on a plurality of ray elastic impedance curves to obtain a ray elastic impedance transition model;
[0161] The seventh obtaining module is used to invert the ray elastic impedance transition model to obtain the ray elastic impedance transition inversion model;
[0162] The eighth obtaining module is used to obtain the Poisson's ratio attribute body and the bulk modulus attribute body based on the ray elastic impedance transition inversion model.
[0163] In some embodiments, the second acquisition module includes:
[0164] The curve acquisition submodule is used to obtain the P-wave and S-wave velocity ratio curve and rock density curve of the target tight sandstone reservoir;
[0165] The fitting submodule is used to fit the P-wave velocity ratio curve and the rock density curve to obtain the probability density function of the P-wave velocity ratio and the rock density.
[0166] In the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.
[0167] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the present application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only.
[0168] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.
Claims
1. A method for predicting the effective porosity of a tight sandstone reservoir, characterized in that: The method comprises: According to the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir, the corresponding relationship between the effective porosity and Young's modulus is determined; Obtaining a Young's modulus attribute body of the target tight sandstone reservoir according to a Poisson's ratio attribute body and a bulk modulus attribute body of the target tight sandstone reservoir, wherein each data point in the Poisson's ratio attribute body and the bulk modulus attribute body corresponds one to one; Based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir, an effective porosity attribute of the target tight sandstone reservoir is obtained.
2. The method for predicting effective porosity of tight sandstone reservoir according to claim 1, characterized in that: Determining the corresponding relationship between the effective porosity and the Young's modulus at multiple depth points in the target tight sandstone reservoir comprises: A two-dimensional coordinate system is established with Young's modulus as the horizontal axis and effective porosity as the vertical axis; Based on the two-dimensional coordinate system, the effective porosity and Young's modulus at multiple depth points in the target tight sandstone reservoir are fitted to obtain the corresponding relationship between the effective porosity and Young's modulus.
3. The method for predicting effective porosity of tight sandstone reservoir according to claim 1, characterized in that: The Young's modulus attribute of the target tight sandstone reservoir is obtained according to the Poisson's ratio attribute and the bulk modulus attribute of the target tight sandstone reservoir, including: Substitute the Poisson's ratio of each data point in the Poisson's ratio attribute body and the bulk modulus of each data point in the bulk modulus attribute body of the target tight sandstone reservoir into the conversion formula to calculate the Young's modulus attribute body of the target tight sandstone reservoir, wherein the conversion formula is: E = 3*K(1-2v); Wherein, E represents Young's modulus, K represents bulk modulus, and v represents Poisson's ratio.
4. The method for predicting effective porosity of tight sandstone reservoir according to claim 1, characterized in that: The method of obtaining the effective porosity attribute of the target tight sandstone reservoir based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir includes: The Young's modulus of each point in the Young's modulus attribute body of the target tight sandstone reservoir is substituted into the corresponding relationship between the effective porosity and the Young's modulus to obtain the effective porosity attribute body of the target tight sandstone reservoir.
5. The method for predicting effective porosity of tight sandstone reservoir according to claim 1, characterized in that: After obtaining the effective porosity attribute of the target tight sandstone reservoir based on the corresponding relationship between the effective porosity and the Young's modulus and the Young's modulus attribute of the target tight sandstone reservoir, the method further includes: The effective porosity attribute volume of the target tight sandstone reservoir is cut to obtain an effective porosity profile, and the effective porosity profile is used to characterize the effective porosity distribution characteristics.
6. The method for predicting effective porosity of tight sandstone reservoir according to claim 1, characterized in that: Before determining the corresponding relationship between the effective porosity and the Young's modulus at multiple depth points in the target tight sandstone reservoir, the method further includes: Obtain core and logging data from multiple layers at different depths in the target tight sandstone reservoir; Based on the cores of multiple layers at different depths in the target tight sandstone reservoir, the effective porosity at multiple depth points is obtained; Based on the XMAC logging curve sequence in the logging data and the effective porosity of the multiple depth points, the Young's modulus of the multiple depth points is obtained.
7. The method for predicting effective porosity of tight sandstone reservoir according to claim 6, characterized in that: The obtaining of Young's modulus of multiple depth points based on the XMAC logging curve sequence in the logging data and the effective porosity of the multiple depth points includes: determining corresponding depths of the plurality of depth points based on the effective porosities of the plurality of depth points; The Young's modulus of the corresponding depths of the multiple depth points in the XMAC logging curve sequence is determined as the Young's modulus of the multiple depth points.
8. The method for predicting effective porosity of tight sandstone reservoir according to claim 1, characterized in that: Before obtaining the Young's modulus attribute of the target tight sandstone reservoir according to the Poisson's ratio attribute and the bulk modulus attribute of the target tight sandstone reservoir, the method further comprises: Obtain the probability density function of the P-wave and S-wave velocity ratio and rock density of the target tight sandstone reservoir; Based on the P-wave velocity ratio and the probability density function of the rock density of the target tight sandstone reservoir, multiple ray elastic impedance curves are obtained; Performing interpolation operation on the plurality of ray elastic impedance curves to obtain a ray elastic impedance transition model; Inverting the ray elastic impedance transition model to obtain a ray elastic impedance transition inversion model; Based on the ray elastic impedance transition inversion model, the Poisson's ratio attribute body and the bulk modulus attribute body are obtained.
9. The method for predicting effective porosity of tight sandstone reservoir according to claim 8, characterized in that: The probability density function of obtaining the P-wave velocity ratio and rock density of the target tight sandstone reservoir includes: Obtain the P-wave and S-wave velocity ratio curve and rock density curve of the target tight sandstone reservoir; The P-wave velocity ratio curve and the rock density curve are fitted to obtain a probability density function of the P-wave velocity ratio and the rock density.
10. A device for predicting the effective porosity of a tight sandstone reservoir, characterized in that: The device comprises: A determination module, for determining a corresponding relationship between effective porosity and Young's modulus according to effective porosity data and Young's modulus data of a target tight sandstone reservoir; A first obtaining module is used to obtain a Young's modulus attribute body according to a Poisson's ratio attribute body and a bulk modulus attribute body of a target tight sandstone reservoir; The second obtaining module is used to substitute the Young's modulus attribute body into the corresponding relationship between the effective porosity and the Young's modulus to obtain the effective porosity attribute body.