Method for obtaining salt cavern Q value model and method for obtaining Q value

Abstract

The invention belongs to the technical field of oil and gas exploration and development, and particularly relates to a method for obtaining a salt cavern Q value model and a method for obtaining a Q value. According to the method for obtaining the salt cavern Q value model, a deep well logging point M is arranged in a rock cavern area; obtaining a second speed curve VM through logging information of the deep logging point M; according to the lithologic depth DpF of a sudden change point of the second speed curve VM; obtaining a Q-V value through logging information of the deep logging point M, and fitting the Q-V value to obtain a Q value model corresponding to the lithologic depth DpF; wherein M belongs to (1, 2, 3,..., m), and m represents the number of deep logging points; f belongs to (1, 2, 3,..., f), and f represents the layering number of lithology. According to the method, the Q value model is obtained through lithologic layering, and the obtained Q value model not only reduces the calculation amount, but also is more accurate; the Q value of the salt cavern can be obtained more accurately through the Q value model obtained through the method, imaging of the salt cavern is more accurate, a salt cavern reservoir is accurately described, and therefore the salt cavern is effectively utilized.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploration and development, and particularly relates to a method for obtaining a salt cavern Q value model and a method for obtaining a Q value. Background Art

[0002] Salt caverns after mining have good sealing and high stability, making them effective storage sites for a variety of new energy sources such as energy storage and gas storage. However, before using them for energy storage, it is necessary to first characterize the underground structures such as the distribution characteristics of salt mines and the distribution characteristics of the top and bottom plates and structural characteristics in detail to ensure that the stratigraphic distribution characteristics of salt caverns can be utilized.

[0003] In order to ensure the safety and economic benefits of salt cavern energy storage, the salt caverns used for energy and gas storage are generally shallow, at a depth of 500-800m, and have the conditions for utilization. In order to obtain images of shallow salt caverns, and thus affect the description and effective utilization of salt cavern reservoirs, it is necessary to first obtain an effective quality factor Q.

[0004] In areas where salt caves are developed, the compaction of near-surface strata is generally weak, the structure is loose, and the Q value is generally small. When seismic waves pass through near-surface strata, the absorption attenuation is very serious. Secondly, salt cave development areas have very high requirements for shallow seismic quality. The lithology, velocity, and thickness of complex surface areas often vary greatly in the lateral direction. Traditional Q values ​​(such as Chinese patent application CN113093284A and Chinese patent CN106646601A) have the defect of inaccurate imaging when describing caves.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a method for obtaining a salt cavern Q value model and a method for obtaining a Q value. The present invention obtains a Q value model through lithological stratification, and the obtained Q value model not only reduces the amount of calculation but is also more accurate; when the Q value model obtained by the present invention is used to obtain the Q value of the salt cavern, it is more accurate, so that the imaging of the salt cavern is more accurate, and then the salt cavern reservoir is accurately described, thereby effectively utilizing the salt cavern.

[0007] The present invention includes the following technical solutions:

[0008] A first aspect of the present invention provides a method for obtaining a salt cavern Q value model, comprising the following steps:

[0009] Set up deep logging point M in the rock cave area;

[0010] The second velocity curve V is obtained through the logging data of the deep logging point M M ;

[0011] According to the second speed curve VM The lithology depth Dp of the mutation point F ;

[0012] The QV value is obtained through the logging data of the deep logging point M, and the lithology depth Dp is obtained by fitting the QV value. F The corresponding Q value model;

[0013] Among them, M∈(1,2,3,...,m), m represents the number of deep logging points; F∈(1,2,3,...,f), f represents the number of lithology layers.

[0014] Further, the following steps are included:

[0015] Set up shallow logging point N and deep logging point M in the rock cave area;

[0016] The first velocity curve V is obtained through the logging data of the shallow logging point N N , the second velocity curve V is obtained through the logging data of the deep logging point M M ;

[0017] According to the first speed curve V N The preset lithology depth Dp is obtained from the mutation point N , according to the preset layer lithology depth Dp N Performing a planar partition on the cave area to obtain a partition area G;

[0018] According to the second speed curve V M The lithology depth Dp of the partition area G is obtained by the mutation point G R ;

[0019] The QV value is obtained through the logging data of the deep logging point M, and the lithology depth Dp of the partition area G is obtained by fitting the QV value. G R The corresponding Q value model;

[0020] Where, N∈(1,2,3,...,n), n represents the number of shallow logging points;

[0021] M∈(1,2,3,...,m), m represents the number of deep logging points; G∈(1,2,3,...,g), g represents the number of partitioned areas; R∈(1,2,3,...,r), r represents the number of lithology layers in the partitioned area G.

[0022] Furthermore, the Q value model is

[0023] Among them, A GR , B GR , e are constants, and V represents the speed.

[0024] Furthermore, according to the preset layer lithology depth Dp N The method of plane partitioning the cave area to obtain G partition areas is: any two Dp in the same partition area N The difference is less than the preset value.

[0025] Furthermore, the preset value is 0.5m.

[0026] Furthermore, the preset layer is the first layer of the rock formation.

[0027] Furthermore, the lithology depth Dp of the partition area G is obtained according to the mutation points of the M velocity curves. G R Obtained by the following formula:

[0028] Where J represents the number of deep logging points in the partition area.

[0029] Furthermore, n <m。

[0030] Furthermore, the maximum area enclosed by the deep logging points M is smaller than or equal to the maximum area enclosed by the shallow logging points N.

[0031] A second aspect of the present invention provides a method for obtaining a salt cavern Q value, including the method for obtaining a salt cavern Q value model described above, wherein the method for obtaining a salt cavern Q value is:

[0032] Obtain the lithology and velocity V of the caves within the partitioned area;

[0033] The velocity V is introduced into the Q value model of the rock properties of the cave to obtain the salt cave Q value.

[0034] Further, a device for obtaining the Q value of a salt cavern is included, wherein the device includes a calculation module;

[0035] The calculation module stores the Q value model obtained by the method for obtaining the salt cave Q value model;

[0036] The calculation module calls a Q value model corresponding to the lithology of the cave according to the lithology of the cave, and obtains the Q value of the salt cave through velocity V calculation.

[0037] By adopting the above technical solution, the present invention has the following advantages:

[0038] The present invention obtains a Q value model through lithology stratification, and the obtained Q value model not only reduces the amount of calculation but is also more accurate; when the Q value model obtained by the present invention is used to obtain the Q value of the salt cavern, it is more accurate, so that the imaging of the salt cavern is more accurate, and then the salt cavern reservoir is accurately described, so that the salt cavern is effectively utilized.

[0039] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A process of obtaining a salt cave Q value model in an embodiment of the present invention Figure 1 ;

[0042] Figure 2 A process of obtaining a salt cave Q value model in an embodiment of the present invention Figure 2 ;

[0043] Figure 3 A schematic diagram of well logging points selected in an embodiment of the present invention;

[0044] Figure 4 is a schematic diagram of a first speed curve in an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of QV fitting in an embodiment of the present invention;

[0046] In the figure: 10-deep logging point, 20-shallow logging point, 30-mutation point. DETAILED DESCRIPTION

[0047] The following description provides many different embodiments or examples for implementing different features of the present invention. The components and arrangements described in the following specific examples are only used to simplify the present invention and are only used as examples, not to limit the present invention.

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution 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 part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In seismic logging, a sudden change in lithology will cause different degrees of absorption and attenuation of the received seismic signal, resulting in a velocity mutation when different lithologies transition; the corresponding QV value will also have a mutation when the velocity mutation occurs; the QV model obtained in the prior art does not take into account the velocity mutation caused by lithology changes, so the QV obtained by fitting is not accurate enough, which in turn affects the stacking imaging of shallow caves and even causes the illusion of geological space, which in turn leads to the wrong interpretation of caves.

[0050] To this end, this embodiment provides a method for obtaining a salt cave Q value model, such as Figure 1 As shown, the following steps are included:

[0051] Set up deep logging point M in the rock cave area;

[0052] The second velocity curve V is obtained through the logging data of the deep logging point M M ;

[0053] According to the second speed curve V M The lithology depth Dp of the mutation point F ;

[0054] The QV value is obtained through the logging data of the deep logging point M, and the lithology depth Dp is obtained by fitting the QV value. F The corresponding Q value model;

[0055] Among them, M∈(1,2,3,...,m), m represents the number of deep logging points; F∈(1,2,3,...,f), f represents the number of lithology layers.

[0056] The present invention fits the QV value according to the lithology to obtain the Q value model corresponding to each lithology; the obtained Q value model not only reduces the amount of calculation but also is more accurate.

[0057] Furthermore, the Q value model obtained by the present invention is more accurate when obtaining the Q value of the salt cavern, making the imaging of the salt cavern more accurate, and then accurately describing the salt cavern reservoir, so as to effectively utilize the salt cavern. At the same time, the characteristics of velocity mutation are used to distinguish lithology, which also reduces the workload and calculation amount of lithology zoning, and also has the advantages of high efficiency and low cost.

[0058] In order to reduce the amount of calculation in the fitting process and improve the fitting efficiency, the present invention fits the QV value by the power exponential fitting method to obtain the Q value model:

[0059] Among them, A F , B F , e are constants, and V represents the speed.

[0060] It should be noted that, although the present invention improves the fitting efficiency by fitting through a power exponential function, it does not represent a limitation on the fitting method, and other forms of fitting methods should also be within the protection scope of the present invention.

[0061] The above method only considers the mutation caused by lithology, but does not consider the QV value mutation caused by the ups and downs of rock formations.

[0062] To this end, this embodiment also provides a method for obtaining a salt cave Q value model, such as Figure 2 As shown, the following steps are included:

[0063] Set up shallow logging point N and deep logging point M in the rock cave area;

[0064] The first velocity curve V is obtained through the logging data of the shallow logging point N N , the second velocity curve V is obtained through the logging data of the deep logging point M M ;

[0065] According to the first speed curve V N The preset lithology depth Dp is obtained from the mutation point N , according to the preset layer lithology depth Dp N Performing a planar partition on the cave area to obtain a partition area G;

[0066] According to the second speed curve V M The lithology depth Dp of the partition area G is obtained by the mutation point G R ;

[0067] The QV value is obtained through the logging data of the deep logging point M, and the lithology depth Dp of the partition area G is obtained by fitting the QV value. G R The corresponding Q value model;

[0068] Among them, N∈(1,2,3,...,n), n represents the number of shallow logging points; M∈(1,2,3,...,m), m represents the number of deep logging points; G∈(1,2,3,...,g), g represents the number of partitioned areas, and R∈(1,2,3,...,r), r represents the number of lithological layers in partitioned area G.

[0069] The present invention not only reduces the complexity of calculation (the data is more accurate and has no mutation points during the fitting process) but also improves the accuracy of the Q value model by considering the mutation caused by lithology and the mutation caused by the height fluctuation of the rock layer.

[0070] The shallow logging point is selected to utilize the first velocity curve V in the logging data. Nto perform planar partitioning, compared with directly using the second velocity curve V M to perform planar partitioning, has the advantage of reducing the amount of computation.

[0071] In some embodiments, the Q-value model is

[0072] wherein, A G R and B G R and e are all constants, and V represents velocity.

[0073] In some embodiments, according to the preset layer lithology depth Dp N the method for performing planar partitioning on the cavern area to obtain G partition regions is: the difference between any two Dp N in the same partition region is less than the preset value. By partitioning in this way, it has the advantages of simple operation and high efficiency.

[0074] At the same time, consider reducing the computation and eliminating the influence of sudden changes in Q-V values caused by the undulating changes of rock layers; in some embodiments, the preset value is 0.5 m.

[0075] In some embodiments, the preset layer is the first layer of the rock formation. This can reduce the logging depth of shallow logging points and improve the measurement efficiency; at the same time, the calculation amount of the obtained first velocity curve V N will be smaller, improving the calculation efficiency.

[0076] In the same partition, due to the folding of the strata, there are certain differences in the lithology depths of deep logging points. In order to obtain a unique Q-value model for different lithologies in the same partition, it is necessary to process the lithologies of all deep logging points located in the same partition. In some embodiments, according to the mutation points of the second velocity curve V M the lithology depth Dp G R of the partition region G is obtained through the following formula:

[0077] wherein, J represents the number of deep logging points in the partition region.

[0078] In some embodiments, n < m. For planar partitioning, the number of shallow logging points only needs to ensure that the range it includes can contain all deep logging points. However, the logging data of deep logging points is used to obtain Q-V values, and then further obtain the Q-value model. Therefore, in order to improve the accuracy of the obtained Q-value model, the number of deep logging points needs to be greater than the number of shallow logging points.

[0079] In some embodiments, the maximum area enclosed by the deep well logging points M is smaller than or equal to the maximum area enclosed by the shallow well logging points N. In this way, all deep well logging points can be included in the partition area G.

[0080] Through the above specific implementation method, the following Figure 3 The cave area shown in the figure, wherein the circles represent deep logging points 10 and shallow logging points 20, and the diameter of the circle used to represent the shallow logging point 20 in the figure is larger than the diameter of the circle representing the deep logging point 10; 24 shallow logging points 20 are selected in this area, that is, N∈(1,2,3,...,24); 184 deep logging points 10 are selected in this area, that is, M∈(1,2,3,...,184).

[0081] Among them, the selection criteria of deep logging point 10 and shallow logging point 20 are: 1. Select points on both sides of the sudden change of surface elevation; 2. Select points evenly in the same altitude area; 3. Select points more densely in high and steep places; 4. Select points more densely in the fully covered area of ​​the study area.

[0082] The logging data of the shallow logging point N and the deep logging point M are obtained by the micro-logging method; the first velocity curve V is obtained by the logging data of the shallow logging point N N , V N ∈(V1,V2,V3,...,V 24 );like Figure 4 As shown, the first velocity curve represents the relationship between velocity and depth Dp. The figure only shows the first velocity curve of a shallow logging point. When the lithology changes, there is a mutation point 30, and the lithology can be stratified through the mutation point 30. N Get 24 preset layer lithology depths Dp N , Dp N ∈(Dp1,Dp2,Dp3,...,Dp 24 ); The preset layer can be the depth of any lithology. Preferably, the preset layer is the first layer of the rock formation, that is, Figure 4 The loess layer shown; Dp obtained by N ∈(Dp1,Dp2,Dp3,...,Dp 24 ) Divide the cave area into partition areas G.

[0083] The number of partition regions G is indefinite, and depends on the depth values ​​Dp1, Dp2, Dp3, ..., Dp 24 Determine the difference between .

[0084] Each partition area G includes multiple deep logging points. The multiple deep logging points in each partition area G are divided into two groups; each partition area G is divided into two groups according to the second velocity curve V of the deep logging points therein. M The corresponding lithology depth Dp is obtained from the mutation point G R Specifically, if the partition area G∈(1,2,3,...,10), the lithology depth of partition area 1 is Dp1 R ;like Figure 5 As shown, the lithology depth Dp1 in the sub-area 1 R The corresponding QV value fitting curve, there are 4 lithologies, then Dp1 R ∈ (Dp11, Dp12, Dp13, Dp14).

[0085] Assume that there are 20 deep logging points in zone 1, then J = 20;

[0086]

[0087] The QV value is obtained through the logging data of the deep logging point in the partition area 1, and the lithology depth Dp1 of the partition area 1 is obtained by fitting the QV value. R The corresponding Q value model; such as Figure 5 As shown, it is the QV value fitting curve, that is, Get loess segment Q1 R =2.12732e 0.0006 V , Salt rock section Q1 R =2.32435e 0.0024 V , Clay segment Q1 R =2.18654e 0.0019 V , sandstone section Q1 R =2.19273e 0.0021 V .

[0088] This embodiment also provides a method for obtaining a salt cavern Q value, including the method for obtaining a salt cavern Q value model described above, wherein the method for obtaining a salt cavern Q value is:

[0089] Obtain the lithology and velocity V of the caves within the partitioned area;

[0090] The velocity V is introduced into the Q value model of the rock properties of the cave to obtain the salt cave Q value.

[0091] In some embodiments, a device for obtaining a salt cavern Q value is included, the device comprising a calculation module;

[0092] The calculation module stores the Q value model obtained by the method for obtaining the salt cave Q value model;

[0093] The calculation module calls a Q value model corresponding to the lithology of the cave according to the lithology of the cave, and obtains the Q value of the salt cave through velocity V calculation.

[0094] Because different lithologies correspond to different Q value models, it is necessary to obtain the velocity V and lithology at the same time so that the Q value model corresponding to the lithology can be selected when calculating the Q value.

[0095] The above method has the advantage of improving the efficiency of obtaining the Q value of the salt cavern.

[0096] Wherein, the computing module includes a memory and a processor, and the memory is used to store the computer program and the Q value model;

[0097] The processor is used to call the Q value model corresponding to the lithology of the cave according to the lithology of the cave when executing the computer program, and obtain the Q value of the salt cave through speed V calculation.

[0098] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0099] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for obtaining a salt cave Q value model, characterized in that: The steps include: Set up deep logging point M in the rock cave area; The second velocity curve V is obtained through the logging data of the deep logging point M M ; According to the second speed curve V M The lithology depth Dp of the mutation point F ; The QV value is obtained through the logging data of the deep logging point M, and the lithology depth Dp is obtained by fitting the QV value. F The corresponding Q value model; Among them, M∈(1,2,3,...,m), m represents the number of deep logging points; F∈(1,2,3,...,f), where f represents the number of lithological layers.

2. A method for obtaining a salt cave Q value model, characterized in that: The steps include: Set up shallow logging point N and deep logging point M in the rock cave area; The first velocity curve V is obtained through the logging data of the shallow logging point N N , the second velocity curve V is obtained through the logging data of the deep logging point M M ; According to the first speed curve V N The preset layer lithology depth Dp is obtained from the mutation point N , according to the preset layer lithology depth Dp N Performing plane partitioning on the cave area to obtain the partition area G; According to the second speed curve V M The lithology depth Dp of the partition area G is obtained by the mutation point GR ; The QV value is obtained through the logging data of the deep logging point M, and the lithology depth Dp of the partition area G is obtained by fitting the QV value. GR The corresponding Q value model; Where, N∈(1,2,3,...,n), n represents the number of shallow logging points; M∈(1,2,3,...,m), m represents the number of deep logging points; G∈(1,2,3,...,g), g represents the number of partitioned areas; R∈(1,2,3,...,r), r represents the number of lithology layers in the partitioned area G.

3. The method for obtaining a salt cave Q value model according to claim 2, characterized in that: The Q value model is Among them, A GR , B GR , e are constants, and V represents the speed.

4. The method for obtaining a salt cave Q value model according to claim 2, characterized in that: According to the preset layer lithology depth Dp N The method of plane partitioning the cave area to obtain G partition areas is: any two Dp in the same partition area N The difference is less than the preset value.

5. The method for obtaining a salt cavern Q value model according to claim 4, characterized in that: The preset value is 0.5m.

6. The method for obtaining a salt cavern Q value model according to claim 2, characterized in that: The preset layer is the first layer of the rock formation.

7. The method for obtaining a salt cave Q value model according to claim 2, characterized in that: The lithology depth Dp of the partition area G is obtained according to the mutation points of M velocity curves. GR Obtained by the following formula: Where J represents the number of deep logging points in the partition area.

8. The method for obtaining a salt cave Q value model according to claim 2, characterized in that: n <m。 9. The method for obtaining a salt cavern Q value model according to claim 2, characterized in that: The maximum area enclosed by the deep logging points M is smaller than or equal to the maximum area enclosed by the shallow logging points N.

10. A method for obtaining the Q value of a salt cavern, characterized in that: The method for obtaining a salt cavern Q value model according to any one of claims 1 to 9 is as follows: Obtain the lithology and velocity V of the caves within the partitioned area; The velocity V is introduced into the Q value model of the rock properties of the cave to obtain the salt cave Q value.

11. A method for obtaining the Q value of a salt cavern according to claim 10, characterized in that: A device for obtaining a salt cavern Q value is provided, wherein the device comprises a calculation module; The calculation module stores the Q value model obtained by the method for obtaining the salt cave Q value model; The calculation module calls a Q value model corresponding to the lithology of the cave according to the lithology of the cave, and obtains the Q value of the salt cave through velocity V calculation.

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