Method, device, medium and processor for establishing a layer velocity model of a gypsum-salt interbed

Abstract

The embodiment of the present application provides a kind of method, device, medium and processor for establishing layer velocity model of gypsolith interbed, belong to oil and gas exploration technical field.The method comprises: establishing the formation model of target gypsolith interbed, and according to the resolution accuracy of seismic resolution, determine each formation in formation model as thin formation or thick formation, wherein, formation model includes at least one gypsolith formation and at least one salt rock formation;Different interpretation methods are used for thick formation and thin formation, the top and bottom interface of each formation is obtained, and the formation framework of gypsolith interbed is established;The statistical value of the layer velocity of each formation in formation framework is obtained as the layer velocity of corresponding formation, and the layer velocity model of gypsolith interbed is established.Through the above method, the precision of layer velocity model can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration, and in particular to a method, device, medium and processor for establishing a layer velocity model of gypsum-salt rock interlayers. Background Art

[0002] Carbonate oil and gas reservoirs often boast large reserves and high single-well production, making them a key component of global oil and gas distribution. However, a significant proportion of carbonate reservoirs are characterized by the vertical development of multiple sets of gypsum and salt rocks above the strata, with these layers forming interbedded layers. Because these interbedded layers exhibit significant plastic deformation and exhibit large vertical and lateral thickness variations, establishing a detailed stratigraphic framework for these layers presents a significant challenge in carbonate reservoir research.

[0003] At the same time, due to the large variations in velocity between different gypsum and salt formations, the traditional three-dimensional velocity modeling method combining conventional seismic velocity spectra with logging velocity has low accuracy in modeling gypsum-salt interbedded formations, which has a great impact on the depiction of the structural morphology and thickness of the underlying carbonate oil and gas reservoirs. As a result, establishing an accurate interval velocity model for gypsum-salt interbedded formations is the second difficulty in studying carbonate oil and gas reservoirs. Summary of the Invention

[0004] The purpose of the embodiment of the present invention is to provide a method that can establish a fine stratigraphic framework and interval velocity model for gypsum-salt rock interbeds.

[0005] To achieve the above objectives, an embodiment of the present invention provides a method for establishing an interlayer velocity model of gypsum-salt rock interlayers, comprising:

[0006] Establishing a stratigraphic model of the target gypsum-salt interbed, and determining whether each stratum in the stratigraphic model is a thin stratum or a thick stratum based on the identifiable accuracy of the seismic resolution, wherein the stratigraphic model includes at least one gypsum-salt interbed and at least one salt-salt interbed;

[0007] Different interpretation methods are used for thick and thin strata to obtain the top and bottom interfaces of each stratum and establish a stratigraphic framework for gypsum-salt interbeds.

[0008] The interval velocity statistics of each stratum in the stratigraphic framework are obtained as the interval velocity of the corresponding stratum, and an interval velocity model of the gypsum-salt rock interlayer is established.

[0009] Preferably, the method for establishing the interlayer velocity model of gypsum-salt rock interlayers further includes:

[0010] The interval velocity model is applied to the time domain structural model of the gypsum-salt rock interlayer to obtain the depth domain model of the gypsum-salt rock interlayer, which reflects the distribution of structural highs and lows of the target gypsum-salt rock interlayer.

[0011] Optionally, a stratigraphic model of the target gypsum-salt rock interbed is established, including:

[0012] Draw a well-connected stratigraphic comparison map of the area to which the target gypsum-salt rock interlayer belongs and the adjacent areas, and establish a regional geological model of the target gypsum-salt rock interlayer to confirm the number and arrangement order of gypsum rock strata and salt rock strata included in the target gypsum-salt rock interlayer.

[0013] Optionally, for thick formations, obtaining the top and bottom interfaces of each formation includes: finely calibrating synthetic seismic records of wells drilled in the target gypsum-salt interbed area, and interpreting the top and bottom interfaces of the thick formation using three-dimensional seismic data.

[0014] Furthermore, 3D seismic data is used to interpret the top and bottom interfaces of thick formations, including:

[0015] Obtain synthetic seismic records of the target gypsum-salt interbed area and perform calibration;

[0016] On the basis of synthetic seismic record calibration, the intersection interface between the thick stratum and the adjacent stratum is determined according to the continuous seismic reflection characteristics and is used as the top interface or bottom interface of the thick stratum.

[0017] Furthermore, the continuous seismic reflection feature appears when at least one of the upper and lower adjacent strata is a thick stratum, and the correspondence between the seismic reflection feature and the two adjacent strata includes one or more of the following:

[0018] When the salt rock formation is thick, if the gypsum rock formation above the salt rock formation is thin, a continuous wave peak reflection feature will appear at the intersection interface;

[0019] When the salt rock formation is thick, if the gypsum rock formation above the salt rock formation is also thick, a continuous strong trough reflection feature will appear at the intersection interface;

[0020] When the gypsum rock formation is thick, if the salt rock formation above the gypsum rock formation is also thick, a strong amplitude and strong continuity wave peak reflection feature appears at the intersection interface; and

[0021] When the gypsum formation is a thick formation, if the gypsum formation is the bottom layer of the target gypsum-salt rock interlayer, a weak-amplitude medium-continuous trough reflection feature appears at the intersection interface.

[0022] Optionally, for thin strata, obtaining the top and bottom interfaces of each stratum includes: using a well layering and seismic interpretation horizon creation technique to generate the top and bottom interfaces of the thin stratum.

[0023] Furthermore, the seismic interpretation horizon technology is used to create well layers to generate the top and bottom interfaces of thin strata, including:

[0024] According to the well layering data and the horizon constraint of the adjacent known stratum, the stratum trend characteristics at the surrounding diffusion positions are gradually calculated from the well point position of the gypsiferous stratum or the salt rock stratum, and the overall trend of the stratum change reflected by the velocity field is finally obtained; and

[0025] According to the overall trend, the top interface and the bottom interface of the gypsiferous stratum or the salt rock stratum are determined,

[0026] The well layering data comprises the stratum change trend between wells.

[0027] Further, the stratum trend characteristics at the surrounding diffusion positions are gradually calculated by the interpolation method.

[0028] Optionally, the histogram method is used to obtain the statistical value of the stratum velocity of each stratum in the stratum framework.

[0029] On the other hand, the application provides a device for establishing a stratum velocity model of a gypsiferous-salt rock interbedded stratum, comprising:

[0030] A stratum model construction module is configured to establish a stratum model of a target gypsiferous-salt rock interbedded stratum, and determine each stratum in the stratum model as a thin stratum or a thick stratum according to the seismic resolution recognizable accuracy, wherein the stratum model comprises at least one gypsiferous stratum and at least one salt rock stratum;

[0031] A stratum framework construction module is configured to obtain the top and bottom interfaces of each stratum by using different interpretation methods for the thick stratum and the thin stratum, and establish a stratum framework of the gypsiferous-salt rock interbedded stratum; and

[0032] A stratum velocity model construction module is configured to obtain the statistical value of the stratum velocity of each stratum in the stratum framework, and use the statistical value as the stratum velocity of the corresponding stratum, and establish a stratum velocity model of the gypsiferous-salt rock interbedded stratum.

[0033] Preferably, the device further comprises:

[0034] A structure analysis module is configured to apply the stratum velocity model to a time domain structure model of the gypsiferous-salt rock interbedded stratum, and obtain a depth domain model of the gypsiferous-salt rock interbedded stratum to reflect the distribution of the structure high points and low points of the target gypsiferous-salt rock interbedded stratum.

[0035] On the other hand, the application provides a machine readable storage medium, which stores instructions for causing a machine to execute the method for establishing a stratum velocity model of a gypsiferous-salt rock interbedded stratum.

[0036] On the other hand, the application provides a processor for running a program, wherein the program is used to execute the method for establishing a stratum velocity model of a gypsiferous-salt rock interbedded stratum when the program is run.

[0037] Through the technical scheme, the stratum model of the target gypsum-salt interbedded layer is established first, and each stratum in the stratum model is divided into a thin stratum or a thick stratum according to the seismic resolution recognizable accuracy, then different interpretation modes are used for the thin stratum and the thick stratum respectively to determine the top and bottom interfaces of each stratum, so that the fine stratum framework of the target gypsum-salt interbedded layer is obtained, and then the interval velocity statistical value of each stratum is taken as the interval velocity of the corresponding stratum to establish the interval velocity model of the target gypsum-salt interbedded layer, which can effectively improve the accuracy of the interval velocity model.

[0038] Other features and advantages of the embodiments of the present application will be described in detail in the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following detailed description, but do not constitute a limitation of the embodiments of the present application. In the drawings:

[0040] Figure 1 is a flow chart of an embodiment of the method for establishing the interval velocity model of the gypsum-salt interbedded layer of the present application;

[0041] Figure 2 is a time domain structure diagram of the implementation object of the embodiment shown in Figure 1 ;

[0042] Figure 3 is a time domain structure diagram of the implementation object of the embodiment shown in Figure 1 ; Figure 2

[0043] Figure 4 is a depth domain structure diagram obtained by applying the interval velocity model obtained by the embodiment to the time domain structure diagram of Figure 1 ;

[0044] Figure 5 is a geological model schematic diagram of the target gypsum-salt interbedded layer established by the embodiment; Figure 1

[0045] Figure 6 is a synthetic seismic record of the drilled well in the target gypsum-salt interbedded layer region of the embodiment; Figure 1

[0046] is a fine interpretation of the upper salt rock top interface, the middle gypsum rock top interface, the lower salt rock top interface and the top and bottom interfaces of the lower gypsum rock in Figure 7 according to the synthetic seismic record in Figure 6 ; Figure 4

[0047] Figure 8 is a fine interpretation of the upper salt rock top interface, the middle gypsum rock top interface, the lower salt rock top interface and the top and bottom interfaces of the lower gypsum rock in Figure 4 ​​​A detailed interpretation of the top and bottom interfaces of the lower salt rock;

[0048] Figure 9 Based on Figure 8 The obtained planar distribution of the lower salt rock;

[0049] Figure 10 Schematic diagram of the technical method for creating seismic interpretation horizons based on well stratification;

[0050] Figure 11 Based on Figure 10 The layers shown are automatically generated by the Figure 4 the top interface of the upper gypsum in the;

[0051] Figure 12 For comprehensive Figure 7-11 The conclusions obtained are the fine stratigraphic framework of the target gypsum-salt interbed;

[0052] Figures 13A-13E for Figure 12 The histogram of the layer velocity of each layer in , where Figure 13A The middle filling part is the velocity histogram of the upper gypsum layer. Figure 13B The middle filling part is the velocity histogram of the upper salt rock layer. Figure 13C The middle filling part is the velocity histogram of the middle gypsum layer. Figure 13D The middle filling part is the velocity histogram of the lower salt rock layer. Figure 13E The middle filling part is the velocity histogram of the lower gypsum layer;

[0053] Figure 14 For comprehensive Figure 12 、 13A -Interval velocity model of the target gypsum-salt interbedded strata obtained by 13E; and

[0054] Figure 15 It is a structural diagram of an embodiment of a device for establishing an interlayer velocity model of gypsum-salt rock interlayers according to the present invention. DETAILED DESCRIPTION

[0055] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0056] The embodiment of the present invention provides a method for establishing a layer velocity model of gypsum-salt rock interlayer. The process of the method is as follows: Figure 1 As shown, the implementation steps include:

[0057] Step 1: Establish a stratigraphic model of the target gypsum-salt interbed, and determine whether each stratum in the stratigraphic model is a thin stratum or a thick stratum based on the identifiable accuracy of the seismic resolution, wherein the stratigraphic model includes at least one gypsum-salt interbed and at least one salt-salt interbed.

[0058] Step 2: Use different interpretation methods for thick and thin strata to obtain the top and bottom interfaces of each stratum and establish a stratigraphic framework for the interbedded gypsum and salt rocks.

[0059] Step 3: Obtain the interval velocity statistics of each stratum in the stratigraphic framework as the interval velocity of the corresponding stratum, and establish an interval velocity model for the gypsum-salt rock interlayer.

[0060] It should be noted that the method for establishing the interval velocity model of the gypsum-salt rock interlayer according to this embodiment can first obtain the fine stratigraphic framework of the target gypsum-salt rock interlayer, and then use the average interval velocity of each layer as the interval velocity of the corresponding layer to establish the interval velocity model based on the fine stratigraphic framework. Furthermore, the obtained interval velocity model can also be applied to Figure 2 The time domain construction model shown in the figure is converted into time-depth, and the following is obtained: Figure 3 The depth domain structural model is shown. Figure 2 When the contour lines in are for two-way travel, small values ​​represent high structures and large values ​​represent low structures; Figure 3 In order to apply the interval velocity model obtained according to this embodiment to Figure 2 The time-domain structural model shown in the figure is a depth-domain structural map after time-depth conversion. The contour lines represent the altitude. Large contour values ​​represent high structures, while small contour values ​​represent low structures. Time-depth conversion refers to calculating the depth (or altitude) of each location in the target gypsum-salt interbed according to the following formula:

[0061] Depth = earthquake time * layer velocity.

[0062] from Figure 2 and Figure 3 From the comparison, the interpreted structural high and low points have a large change. For example, the position shown in circle A is a structural trap with high in the middle and low around. Figure 2 ), the position of the cross star indicates that the trap has a structural high point, while in the depth domain structural map ( Figure 3 ), two structural high points appear, and their positions vary greatly from those in the time domain structural diagram; for example, the position shown in circle B is different from that in the time domain structural diagram ( Figure 2 ) shows that the structure is higher overall, but in the depth domain structure map ( Figure 3 ) shows a lower structure; for example, at the positions of C and D, the time domain structure diagram ( Figure 2 ) is characterized by low C and high D, while in the depth domain structure map ( Figure 3) is characterized by high C and low D; at the position shown in circle E, in the time domain structure diagram ( Figure 2 ) is slightly lower than the surrounding strata, while in the depth domain structural map ( Figure 3 ) shows obvious low-level structural features. A comparison before and after time-depth conversion shows that the time-depth conversion based on the interval velocity model of this embodiment corrects the error in the time-domain structural map caused by the gypsum-salt interbeds, making the structural map more accurate.

[0063] Therefore, compared with the prior art, the technical advantages of this embodiment are:

[0064] 1. Clarify the vertical development pattern of gypsum and salt rock interbeds, and obtain a fine stratigraphic framework of the target gypsum and salt rock interbeds

[0065] Through statistics of regional drilled wells, a regional geological model of gypsum-salt interbeds is established to clarify the vertical development pattern of gypsum and salt interbeds. First, it is determined whether each layer in the stratigraphic model of the target gypsum-salt interbed is a thin layer or a thick layer. Then, based on the thickness characteristics of each layer, the top and bottom interfaces of each layer are obtained, thereby establishing a three-dimensional stratigraphic framework for the gypsum-salt interbeds. In other words, the specific three-dimensional distribution of each layer in the stratigraphic framework can be determined.

[0066] 2. Apply the interval velocity of each layer to the above-mentioned fine stratigraphic framework to establish a fine interval velocity model

[0067] By annotating the interval velocity of each layer on a detailed 3D stratigraphic grid, a detailed 3D interval velocity model can be generated. In other words, the velocities at different points within each layer in the stratigraphic grid are treated as equal, and the average interval velocity is used as the equivalent velocity at each point within the layer. This method is particularly suitable for interbedded gypsum-salt rock formations with large vertical and horizontal thickness variations but laterally stable interval velocities.

[0068] 3. The refined interval velocity model is further used for time-depth conversion, which can effectively correct the errors of the time domain structural map and obtain accurate depth domain structural distribution.

[0069] The obtained interval velocity model is applied to the time domain structural model for time-depth conversion, which can correct the errors in the time domain structural map caused by the gypsum-salt interbeds and accurately reflect the distribution of structural highs and lows in the gypsum-salt interbed area.

[0070] The following combination Figure 4-Figure 14 Introduce the preferred implementation of the above embodiment, Figure 4The gypsum-salt interbeds in the study area shown are used as the implementation object. First, a stratigraphic model of the gypsum-salt interbeds is established using the wells drilled in the area. The seismic resolution can be used to identify the accuracy and distinguish the thin and thick layers of gypsum and salt strata. Then, different interpretation methods are used for the thick and thin gypsum-salt strata to obtain the top and bottom interfaces of each gypsum-salt interbed, and then a fine stratigraphic framework of the gypsum-salt interbed is established. Finally, within the fine stratigraphic framework of the gypsum-salt interbed, the average interval velocity of each layer drilled in the area is statistically analyzed as the interval velocity of the layer, and an interval velocity model of the gypsum-salt interbed is established. The specific implementation steps are as follows:

[0071] Step 1: Draw a comparative map of the well-connected strata in the study area and adjacent areas, establish a regional geological model of gypsum-salt rock interbeds, and distinguish thin and thick layers of gypsum and salt rock strata with an accuracy that can be identified by seismic resolution.

[0072] Step 2: Based on the calibration of synthetic seismic records, use 3D seismic data to interpret the top and bottom interfaces of thick gypsum and salt rocks.

[0073] Step 3: Use the well stratification to create seismic interpretation horizon technology to automatically generate the top and bottom interfaces of thin-layer gypsum and salt rock.

[0074] Step 4: Using the top and bottom interfaces of the gypsum rock and salt rock obtained in steps 2 and 3, a fine stratigraphic framework of the gypsum-salt rock interbeds is established.

[0075] Step 5: Calculate the average interval velocity of each gypsum and salt rock formation drilled in the region as the interval velocity of the layer.

[0076] Step 6: Fill the fine stratigraphic framework established in step 4 with the average interval velocity obtained in step 5 to establish an interval velocity model for the gypsum-salt rock interbedded strata.

[0077] This embodiment provides a method for establishing a fine stratigraphic framework and interval velocity model for gypsum-salt rock interbeds. The technical advantages thereof are:

[0078] 1. Establish a regional geological model of gypsum-salt interbeds through statistics of wells drilled in the region, and clarify the vertical development pattern of gypsum-salt interbeds;

[0079] Second, different interpretation methods are adopted to accurately obtain the top and bottom interfaces of each gypsum and salt rock based on the different development characteristics of thick and thin gypsum and salt rock formations. In particular, to address the difficulty of fine seismic interpretation of thin gypsum and salt rock, a method is proposed to automatically generate the top and bottom interfaces of thin gypsum and salt rock by creating seismic interpretation horizons in separate wells, significantly improving the accuracy of the fine stratigraphic framework of the gypsum and salt rock interbeds.

[0080] 3. The problem that the traditional three-dimensional velocity modeling method combining seismic velocity spectrum with logging velocity has low modeling accuracy for gypsum-salt interbedded strata due to the large variations in vertical and horizontal thickness of gypsum and salt rock strata.

[0081] In the fine stratum framework of the embodiment, the well logging statistics single velocity is filled as the stratum velocity of the layer, so that a more accurate stratum velocity model of the gypsum-salt interbedded stratum is obtained.

[0082] In the embodiment, step one uses the drilled wells in the region to establish a well-to-well stratum correlation map of the target region and the adjacent region, as shown in FIG. 1, which shows that from top to bottom, there are five sets of gypsum and salt strata, i.e., upper gypsum, upper salt, middle gypsum, lower salt and lower gypsum, which presents a gypsum-salt interbedded pattern. Figure 4 Based on this understanding, a regional gypsum-salt interbedded regional geological pattern is further established, as shown in FIG. 2. Figure 5

[0083] According to the gypsum and salt stratum thickness statistics table of each well (see Table 1 below), it can be determined that each layer in the geological pattern map should belong to a thin stratum or a thick stratum. Figure 5

[0084] Table 1 Statistics of different gypsum and salt stratum thicknesses of each well

[0085]

[0086] From the statistical results in Table 1, the upper gypsum stratum shown by each well is relatively thin, with a distribution of 4.5m-9m and an average thickness of 7m; the upper salt thickness varies greatly, with a distribution of 139.5m-893.5m and an average thickness of 472m; the middle gypsum stratum thickness is distributed in 73m-154.5m, with an average thickness of 100m; the lower salt stratum varies greatly between wells, with a distribution of 5m-94m and an average thickness of 49m; and the lower gypsum average stratum thickness is distributed in 133m-348m, with an average thickness of 243m.

[0087] According to the principle of seismic interpretation resolution (for example, with a speed of 5000m / s and a seismic main frequency of 30Hz, the seismic resolution is about 40m according to the formula), when the layer thickness is less than 40m, the seismic interpretation is not possible, which is defined as a thin layer, and when the layer thickness is greater than 40m, the seismic interpretation is possible, which is defined as a thick layer. Accordingly, in the research region of the embodiment, as shown in FIG. 3, the upper gypsum is defined as a thin layer, and the upper salt, middle gypsum, lower salt and lower gypsum should all be defined as thick layers. In subsequent steps, the thick layers and thin layers are obtained by different ways. Figure 4

[0088] In the embodiment, for thick strata, the top and bottom interfaces of each stratum can be obtained by: performing fine synthetic seismic record calibration on the drilled wells in the target gypsum-salt interbedded region, and using three-dimensional seismic data to interpret the top and bottom interfaces of the thick strata.

[0089] Further, the top and bottom interfaces of the thick strata can be interpreted by:​​​​

[0090] First, obtain synthetic seismic records of the target gypsum-salt interbed area and perform calibration.

[0091] Specifically, the theoretical Ricker wavelet of the corresponding main frequency is first convolved with the reflection coefficient sequence calculated from the logging acoustic impedance curve to generate a synthetic seismic record; then the synthetic seismic record is aligned with the main wave group of the actual seismic record near the well, and the appropriate time window is selected to extract the seismic wavelet; finally, the newly extracted wavelet is used to generate a new synthetic seismic record, such as Figure 6 As shown;

[0092] Then, based on the calibration of synthetic seismic records, the intersection interface between the thick stratum and the adjacent stratum is determined according to the continuous seismic reflection characteristics and is used as the top interface or bottom interface of the thick stratum.

[0093] Specifically, first, when the obtained synthetic record and the seismic record reach the best match, the well-seismic correlation coefficient is recorded (the well-seismic correlation coefficient in this embodiment is 0.63), and the synthetic seismic record at this time is used to calibrate and determine the following: Figure 7 The seismic reflection characteristics of the four thick strata, namely, upper salt rock, middle gypsum rock, lower salt rock and lower gypsum rock, are shown in the figure. Among them, the top surface of the upper salt rock is a continuous wave crest reflection feature; the top surface of the middle gypsum rock is a strong amplitude and strong continuity wave crest reflection feature; the top surface of the lower salt rock is a continuous strong wave trough reflection feature; the top surface of the lower gypsum rock is a strong amplitude and strong continuity wave crest reflection feature; the bottom surface of the lower gypsum rock is a weak amplitude and medium continuity wave trough reflection.

[0094] Based on the seismic reflection characteristics of the above strata, 3D seismic data were used to conduct detailed interpretation of the upper salt rock top, middle gypsum rock top, lower salt rock top and lower gypsum rock top and bottom interfaces, such as Figure 7 As shown. The thickness of the lower salt formation in the study area varies significantly. Although there is no obvious lower salt formation at the EKuv-21 well location, a clear eyeball-shaped weak amplitude reflection feature can be seen in the western part of the study area. On the near NE-SW seismic section, the boundary feature of the salt body is obvious. Based on this feature, the top and bottom surfaces of the lower salt are interpreted, as shown in the figure. Figure 8 The thickness of the lower salt rock formation is further calculated, where the location with the largest thickness reflects the location where the lower salt rock formation is widely distributed. Figure 9 The distribution range of the lower salt rock can be seen from the horizontal distribution range. The lower salt rock is mainly distributed in the western and northwest of the study area. The thickness of the lower salt rock formation in the eastern part of the work area is relatively thin. The overall distribution of the salt rock is in the north-northeast direction.

[0095] In this embodiment, for thin strata, obtaining the top and bottom interfaces of each stratum includes: using a well-layered seismic interpretation horizon creation technique to generate the top and bottom interfaces of the thin stratum, including:

[0096] First, based on the well stratification data and the stratigraphic constraints of adjacent known strata, starting from the well point location in the gypsum or salt formation, the stratigraphic trend characteristics at the surrounding diffusion positions are gradually calculated, and finally the overall trend of stratigraphic changes reflected by the velocity field is obtained. The well stratification data includes the stratigraphic change trend between wells.

[0097] Then, based on the overall trend, the top and bottom interfaces of the gypsum formation or salt formation are determined.

[0098] In this embodiment, the statistical results of Table 1 show that the thickness of the upper gypsum stratum is distributed in the range of 4.5m-9m, with an average thickness of 7m. The thickness of the upper gypsum stratum is far less than the accuracy that can be identified by seismic data, so it is impossible to interpret the corresponding layer by relying solely on seismic data like thick layers. To address this problem, a seismic interpretation layer technology is used to create well stratification. The upper salt rock top surface stratification and the upper salt rock top surface layer are constrained. The upper gypsum rock top surface stratification is used, and according to the formation trend characteristics, the upper gypsum rock top surface layer is interpolated. The principle is as follows: Figure 10 The interpretation horizon obtained in this way is consistent with the well layer at the well point location. The stratigraphic changes between wells are constrained by the trend horizon and follow the overall trend of stratigraphic changes reflected by the velocity field. The results are shown in Figure 11 shown.

[0099] Furthermore, the top and bottom interfaces of each stratum obtained above are integrated to establish a fine stratigraphic framework of the target gypsum-salt rock interbed, such as Figure 12 As shown, it can reflect the three-dimensional distribution of each stratum interface, and the superimposed layer model is the stratigraphic framework.

[0100] Furthermore, the average interval velocity of each formation drilled in the study area is statistically analyzed as the interval velocity of the layer.

[0101] It should be noted that, based on regional multi-well statistical analysis, velocity changes in gypsum and salt rocks during the same depositional period are generally stable. Therefore, for gypsum-salt formations in areas with significant tectonic deformation, the interval velocities derived from seismic and well logging velocities may be inaccurate and cannot be used for velocity calculations in gypsum-salt formations. In-depth analysis of their velocity characteristics is required.

[0102] In this embodiment, the histogram method is used to calculate the formation velocity values ​​of upper gypsum salt, upper salt rock, middle gypsum salt, lower salt rock and lower gypsum rock, as shown in FIG. Figures 13A-13EAs shown in the figure, it can be seen that the interlayer velocities of each well position are obviously different, and the velocity of the gypsiferous rock is obviously higher than that of the salt rock formation. Meanwhile, except for the thin layer (in this embodiment, the upper gypsiferous rock formation), the velocity data of other layers are relatively concentrated, and the velocity difference of the same layer between wells is small, so the average velocity of multiple wells is used as the final filling velocity of the layer. According to the statistical analysis results in Table 2 below, the velocity of the upper gypsiferous salt layer is 4802 m / s, the velocity of the upper salt rock layer is 4382 m / s, the velocity of the middle gypsiferous salt layer is 5888 m / s, the velocity of the lower salt rock layer is 4405 m / s, and the velocity of the lower gypsiferous rock layer is 5982 m / s.

[0103] Table 2 Velocity statistics and average velocity table of gypsiferous salt rock formation in this embodiment

[0104]

[0105] It should be noted that, due to the fast change of the vertical and horizontal thickness of the gypsiferous salt rock interbedded layer, the three-dimensional velocity modeling method of the traditional seismic velocity spectrum combined with the logging velocity has low modeling precision for the gypsiferous salt rock interbedded formation. Step four precisely establishes the thickness change and spatial distribution characteristics of the upper gypsiferous salt, the upper salt rock, the middle gypsiferous salt, the lower salt rock and the lower gypsiferous rock, and step five obtains the relatively accurate layer velocity of the upper gypsiferous salt, the upper salt rock, the middle gypsiferous salt, the lower salt rock and the lower gypsiferous rock by using the drilled wells in the region. Therefore, the method for establishing the layer velocity model of the gypsiferous salt rock interbedded formation adopted in this embodiment is: filling a single velocity as the layer velocity of the layer in the precise formation framework established in step four, and the filled velocity is the average layer velocity of the layer obtained in step five, and the obtained layer velocity model is as shown in Figure 14 The above method of taking the average layer velocity as the layer velocity of the layer is especially suitable for the gypsiferous salt rock interbedded formation with large vertical and horizontal thickness change of the gypsiferous salt rock formation, but the same layer velocity is stable in the horizontal direction.

[0106] The embodiment of the present application also provides a device for establishing a layer velocity model of a gypsiferous salt rock interbedded layer, and the component structure is as shown in Figure 15 The device comprises:

[0107] a formation model construction module, which establishes a formation model of a target gypsiferous salt rock interbedded layer, and determines each formation in the formation model as a thin formation or a thick formation according to the resolution recognizable accuracy of the earthquake;

[0108] a formation framework construction module, which adopts different interpretation methods for the thick formation and the thin formation, obtains the top and bottom interfaces of each formation, and establishes a formation framework of the gypsiferous salt rock interbedded layer; and

[0109] a layer velocity model construction module, which obtains the layer velocity statistical value of each formation in the formation framework, takes the layer velocity statistical value as the layer velocity of the corresponding formation, and establishes a layer velocity model of the gypsiferous salt rock interbedded layer.

[0110] Further, the device further comprises a structure analysis module, which applies the interval velocity model to the time domain structure model of the gypsosalt interbedded rock to obtain a depth domain model of the gypsosalt interbedded rock, so as to reflect the distribution of the structure high points and low points of the target gypsosalt interbedded rock.

[0111] In some embodiments, the stratum model construction module establishes a stratum model of the target gypsosalt interbedded rock, comprising:

[0112] A well-to-well stratum correlation chart of the region to which the target gypsosalt interbedded rock belongs and adjacent regions is drawn, and a regional geological model of the target gypsosalt interbedded rock is established, so as to confirm the number of layers and arrangement sequence of the gypsiferous stratum and the salt rock stratum included in the target gypsosalt interbedded rock.

[0113] In some embodiments, the stratum framework construction module obtains the top and bottom interfaces of each stratum for thick strata, comprising: calibrating the fine synthetic seismogram of the drilled well in the target gypsosalt interbedded rock region, and interpreting the top and bottom interfaces of the thick strata by using the three-dimensional seismic data.

[0114] Further, the stratum framework construction module interprets the top and bottom interfaces of the thick strata by using the three-dimensional seismic data, comprising:

[0115] The synthetic seismogram of the region to which the target gypsosalt interbedded rock belongs is obtained, and is calibrated;

[0116] On the basis of the calibration of the synthetic seismogram, the top interface and the bottom interface of the thick stratum are determined according to the seismic reflection characteristics.

[0117] Further, the corresponding relationship between the above seismic reflection characteristics and the top interface and the bottom interface comprises one or more of the following:

[0118] The continuous wave peak reflection characteristics appear at the top interface of the salt rock stratum, and the gypsiferous stratum above the salt rock stratum is a thin stratum;

[0119] The continuous strong wave valley reflection characteristics appear at the top interface of the salt rock stratum, and the gypsiferous stratum above the salt rock stratum is a thick stratum;

[0120] The strong amplitude and strong continuity wave peak reflection characteristics appear at the top interface of the gypsiferous stratum, and the salt rock stratum above the gypsiferous stratum is a thick stratum;

[0121] The weak amplitude and moderate continuity wave valley reflection characteristics appear at the bottom interface of the gypsiferous stratum, and the gypsiferous stratum is the bottom layer of the target gypsosalt interbedded rock.

[0122] Further, the stratum framework construction module obtains the top and bottom interfaces of each stratum for thin strata, comprising: generating the top and bottom interfaces of the thin stratum by using the well layering to create a seismic interpretation horizon technology, comprising:

[0123] Based on the well stratification data and the stratigraphic constraints of adjacent known strata, starting from the well point location in the gypsum or salt formation, the stratigraphic trend characteristics at the surrounding diffusion positions are gradually calculated, and ultimately the overall trend of stratigraphic changes reflected by the velocity field is obtained; and

[0124] According to the overall trend, determine the top and bottom interfaces of the gypsum or salt formations.

[0125] The well stratification data includes the stratigraphic change trends between wells.

[0126] Furthermore, the stratigraphic trend characteristics at the surrounding diffusion locations are gradually calculated by interpolation.

[0127] Furthermore, the histogram method is used to obtain the interval velocity statistics of each layer in the stratigraphic framework.

[0128] An embodiment of the present invention also provides a device for establishing a layer velocity model of gypsum-salt rock interlayers, the device including a processor and a memory, wherein the above-mentioned formation model construction module, formation grid construction module, layer velocity model construction module, and structural analysis module are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions.

[0129] The processor includes a kernel, which retrieves the corresponding program unit from the memory. One or more kernels can be set, and the interlayer velocity model of the gypsum-salt rock interbed can be established by adjusting the kernel parameters.

[0130] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0131] An embodiment of the present invention provides a storage medium having a program stored thereon, which, when executed by a processor, implements the method of establishing an interlayer velocity model of gypsum-salt rock interlayers of the present application.

[0132] An embodiment of the present invention provides a processor, which is used to run a program, wherein when the program is run, the method of establishing an interlayer velocity model of gypsum-salt rock interlayers of the present application is executed.

[0133] An embodiment of the present invention provides a device comprising a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the method steps for establishing an interlayer velocity model for gypsum-salt interbeds described herein are implemented. The device herein may be a server, a PC, a PAD, a mobile phone, or the like.

[0134] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing the program for initializing the steps of the method for establishing an interval velocity model of gypsum-salt rock interbeds of the present application.

[0135] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0136] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0137] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0138] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0139] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0140] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0141] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0142] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0143] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for establishing an interlayer velocity model for gypsum-salt rock interbeds, comprising: Establishing a stratigraphic model of the target gypsum-salt interbed, and determining whether each stratum in the stratigraphic model is a thin stratum or a thick stratum based on the identifiable accuracy of the seismic resolution, wherein the stratigraphic model includes at least one gypsum-salt interbed and at least one salt-salt interbed; Different interpretation methods are used for thick and thin strata to obtain the top and bottom interfaces of each stratum and establish the stratigraphic framework of the gypsum-salt interbeds; Obtaining the interval velocity statistics of each stratum in the stratigraphic framework as the interval velocity of the corresponding stratum, and establishing an interval velocity model of the gypsum-salt rock interlayer. For the thick formation, obtaining the top and bottom interfaces of each formation includes: calibrating synthetic seismic records of wells drilled in the target gypsum-salt rock interbed area, and interpreting the top and bottom interfaces of the thick formation using three-dimensional seismic data. The method of using three-dimensional seismic data to interpret the top and bottom interfaces of the thick formation includes: obtaining synthetic seismic records of the area to which the target gypsum-salt rock interbed belongs and calibrating them; based on the calibration of the synthetic seismic records, determining the intersection interface between the thick formation and the adjacent formation according to continuous seismic reflection characteristics, and using the intersection interface as the top interface or the bottom interface of the thick formation; For the thin strata, obtaining the top and bottom interfaces of each stratum includes: using a well layering and seismic interpretation horizon creation technology to generate the top and bottom interfaces of the thin stratum, The technology of creating seismic interpretation horizons using well stratification to generate the top and bottom interfaces of the thin strata includes: starting from the well point location of the gypsum stratum or the salt rock stratum, based on well stratification data and the horizon constraints of adjacent known strata, gradually calculating the stratum trend characteristics at surrounding diffusion positions, and ultimately obtaining the overall trend of stratum changes reflected by the velocity field; and determining the top and bottom interfaces of the gypsum stratum or the salt rock stratum based on the overall trend, wherein the well stratification data includes the stratum change trend between wells.

2. The method according to claim 1, further comprising: The layer velocity model is applied to the time domain structural model of the gypsum-salt rock interlayer to obtain a depth domain model of the gypsum-salt rock interlayer to reflect the distribution of structural highs and lows of the target gypsum-salt rock interlayer.

3. The method according to claim 1, wherein establishing a stratigraphic model of the target gypsum-salt rock interbed comprises: Draw a well-connected stratum comparison map of the area to which the target gypsum-salt rock interlayer belongs and the adjacent areas, and establish a regional geological model of the target gypsum-salt rock interlayer to confirm the number and arrangement order of the gypsum rock strata and salt rock strata respectively included in the target gypsum-salt rock interlayer.

4. The method according to claim 1, wherein Continuous seismic reflection features occur when at least one of the upper and lower adjacent strata is a thick stratum, and the correspondence between the seismic reflection features and the two adjacent strata includes one or more of the following: When the salt rock formation is a thick formation, if the gypsum rock formation above the salt rock formation is a thin formation, a continuous wave peak reflection feature appears at the intersection interface; When the salt rock formation is a thick formation, if the gypsum rock formation above the salt rock formation is a thick formation, a continuous strong trough reflection feature appears at the intersection interface; When the gypsum rock formation is a thick formation, if the salt rock formation above the gypsum rock formation is a thick formation, a strong amplitude and strong continuity wave peak reflection feature appears at the intersection interface; as well as When the gypsum rock formation is a thick formation, if the gypsum rock formation is the bottom layer of the target gypsum-salt rock interlayer, a weak-amplitude medium-continuous trough reflection feature appears at the intersection interface.

5. The method according to claim 1, wherein the formation trend characteristics at the surrounding diffusion positions are calculated step by step by interpolation method.

6. The method according to claim 1, wherein the histogram method is used to obtain the interval velocity statistics of each formation in the stratigraphic framework.

7. A device for establishing a layer velocity model of gypsum-salt rock interbeds, characterized in that: include: a formation model building module, which establishes a formation model of the target gypsum-salt rock interbed, and determines whether each stratum in the formation model is a thin stratum or a thick stratum based on the identifiable accuracy of the seismic resolution, wherein the formation model includes at least one gypsum rock stratum and at least one salt rock stratum; A stratigraphic framework construction module uses different interpretation methods for thick and thin strata to obtain the top and bottom interfaces of each stratum and establish a stratigraphic framework for the gypsum-salt rock interbed; and The layer velocity model building module obtains the layer velocity statistics of each layer in the stratigraphic framework and uses them as the layer velocity of the corresponding layer to establish the layer velocity model of the gypsum-salt rock interlayer. For the thick formation, obtaining the top and bottom interfaces of each formation includes: calibrating synthetic seismic records of wells drilled in the target gypsum-salt interbed area, and interpreting the top and bottom interfaces of the thick formation using three-dimensional seismic data. The method of using three-dimensional seismic data to interpret the top and bottom interfaces of the thick formation includes: obtaining synthetic seismic records of the area to which the target gypsum-salt rock interbed belongs and calibrating them; based on the calibration of the synthetic seismic records, determining the intersection interface between the thick formation and the adjacent formation according to continuous seismic reflection characteristics, and using the intersection interface as the top interface or the bottom interface of the thick formation; For the thin strata, obtaining the top and bottom interfaces of each stratum includes: using a well layering and seismic interpretation horizon creation technology to generate the top and bottom interfaces of the thin stratum, The technology of creating seismic interpretation horizons using well stratification to generate the top and bottom interfaces of the thin strata includes: starting from the well point location of the gypsum stratum or the salt rock stratum, based on well stratification data and the horizon constraints of adjacent known strata, gradually calculating the stratum trend characteristics at surrounding diffusion positions, and ultimately obtaining the overall trend of stratum changes reflected by the velocity field; and determining the top and bottom interfaces of the gypsum stratum or the salt rock stratum based on the overall trend, wherein the well stratification data includes the stratum change trend between wells.

8. The device according to claim 7, characterized in that Also includes: The structural analysis module applies the layer velocity model to the time domain structural model of the gypsum-salt rock interlayer to obtain a depth domain model of the gypsum-salt rock interlayer to reflect the distribution of structural highs and lows of the target gypsum-salt rock interlayer.

9. A machine-readable storage medium having instructions stored thereon, the instructions being used to cause a machine to execute: the method for establishing an interval velocity model of gypsum-salt rock interlayers according to any one of claims 1 to 6.

10. A processor, characterized in that: Used to run a program, wherein the program is used to execute: the method for establishing an interlayer velocity model of gypsum-salt rock interlayers according to any one of claims 1 to 6.

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