A method and system for identifying and predicting a cream salt body

Abstract

The application provides a gypsiferous salt body identification and prediction method and system, and belongs to the technical field of oil geophysical exploration. The method is based on post-stack seismic data, and on the basis of gypsiferous salt body seismic response characteristic analysis, sensitive attribute optimization is carried out for different geological targets, the sensitivity of gypsiferous salt body main body, boundary and thickness is clearly identified; the plane distribution and spatial development characteristics of the gypsiferous salt body are determined, and then the gypsiferous salt body is comprehensively identified and predicted. The amplitude torsion attribute is used to effectively identify the main body of the salt body; the 90 degree phase rotation attribute is used to accurately calibrate the top and bottom interfaces of the salt body and effectively characterize the thickness of the salt body. Compared with the limitation of the "point" understanding obtained by drilling and logging, the seismic has high plane resolution and can realize the comprehensive prediction of the longitudinal and transverse spatial development characteristics of the salt body; the seismic attribute is derived from the seismic data itself, and compared with the wave impedance inversion, has the advantages of economy and efficiency, and has strong practicality for field development.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petroleum geophysical exploration, and particularly relates to a gypsiferous rock identification and prediction method and system based on amplitude tortuosity and phase rotation attributes. BACKGROUND

[0002] The practice of marine carbonate rock oil and gas exploration at home and abroad shows that the formation of large carbonate rock oil and gas fields is closely related to gypsiferous rock. A large number of studies have proved that gypsiferous rock can play an important role in oil and gas accumulation, and a unique oil and gas reservoir type can be formed in a gypsiferous rock development area. Exploration results show that considerable giant and large oil and gas fields can be found not only above the salt but also in the subsalt layer. The three marine basins of Tarim, Sichuan and Ordos in China all have gypsiferous rock development, and the more developed the gypsiferous rock is, the larger the scale of oil and gas accumulation is, and the higher the exploration effectiveness is.

[0003] The Tarim Basin has huge hydrocarbon potential in its long geological history development process, and different scales of Paleozoic-Mesozoic oil and gas reservoirs have been formed, of which the Tarim oilfield is one. With the continuous deepening of exploration and development work in the Tarim oilfield and the breakthrough of new areas and new layers, the peripheral oil and gas range has become an important target for the sustainable development of the Tarim oilfield. The gypsiferous rock coverage area of the Carboniferous Bachu Formation in the south of the Tarim oilfield has become an important exploration area for the southward expansion of the Tarim oilfield. The coverage area of the gypsiferous rock of the Carboniferous Bachu Formation in the Tarim oilfield is expected to exceed 1500km 2 . For important exploration areas of salt and subsalt reservoir and cap rock characteristics, the problem of drilling and mud logging technology of gypsiferous rock special stratum is faced.

[0004] Gypsum stratum is prone to collapse, lost circulation or sticking accidents during drilling, which brings great difficulties to drilling operations. When drilling through the gypsiferous rock, drilling construction faces the problems of sticking, drill pipe burying and lost circulation caused by salt layer creep flow, so accurate identification and prediction of gypsiferous rock are very important for site construction.

[0005] The Chinese public literature "Mud logging technology of gypsiferous rock stratum in Tarim oilfield" (Logging Engineering, 2007.03) and the Chinese public literature "Salt layer sidetracking technology of S98 well in Tarim area, Xinjiang" (Drilling and Production Technology, 2003) mainly introduce the mud logging technology of gypsiferous rock stratum in the Tarim area and many feasible ways of drilling difficulties, as well as the related technology and construction scheme of salt layer sidetracking.

[0006] The Chinese public literature "Prediction method of gypsiferous rock and analysis of drilling characteristics - taking Bohai Laizhou Bay Sag as an example" (Technical Research, 2015.06) takes the Bohai Laizhou Bay Sag as an example to discuss the prediction method of gypsiferous rock through regional geological background, adjacent well analysis, seismic reflection characteristics and time slice.

[0007] The disclosed document "Identification method and countermeasures of gypsiferous salt rock in drilling engineering--taking Tu 202 well in Dongying sag as an example" (IFEDC, 20193075) takes Tu 202 well in Dongying sag as an example, uses seismic profile, drilling tool engineering parameter, cutting, logging curve and other data to comprehensively judge the development position of gypsiferous salt rock, and puts forward effective measures from drilling technology, drilling fluid system requirement and drilling parameter monitoring three aspects to guarantee the safe and high-quality completion of drilling engineering.

[0008] The Chinese disclosed document "Sedimentary characteristics and development mode of Cambrian gypsiferous salt rock in Tarim Basin" (Petroleum Experimental Geology, 2021.03) mainly analyzes and identifies gypsiferous salt rock based on rock type, lithofacies characteristics, logging characteristics and seismic characteristics, and carries out research on the sedimentary characteristics of gypsiferous salt rock through field survey, seismic interpretation and comprehensive analysis of exploration well data, compiles the sedimentary facies map of gypsiferous salt rock layer, and establishes the development and genesis mode of middle-lower Cambrian gypsiferous salt rock.

[0009] At present, the identification and prediction technology of gypsiferous salt layer is mainly based on mud logging, logging and cutting observation, and the seismic identification method is mainly based on seismic reflection characteristics and time slice analysis to infer the distribution of gypsiferous salt rock. There is a lack of systematic seismic attribute identification and prediction method of gypsiferous salt body, and there is little research on the seismic prediction method of gypsiferous salt body, boundary and development thickness based on different targets. SUMMARY

[0010] The purpose of the present application is to solve the problems existing in the prior art, provide a gypsiferous salt body identification and prediction method based on amplitude torsion and phase rotation attribute, solve the prediction problems of gypsiferous salt layer main body, boundary and thickness, provide reliable technical support for field logging and drilling construction, and guarantee the adjustment of salt under deep reservoir exploration and drilling scheme.

[0011] The present application is realized by the following technical scheme:

[0012] In a first aspect of the present application, a gypsiferous salt body identification and prediction method is provided, which is based on post-stack seismic data, and on the basis of gypsiferous salt body seismic response characteristic analysis, sensitive attributes are optimized for geological targets to clearly identify the sensitivity of gypsiferous salt main body, boundary and thickness; the planar distribution and spatial development characteristics of gypsiferous salt body are determined, and then the gypsiferous salt body is identified and predicted.

[0013] Further improvement of the present application is:

[0014] The method comprises the following steps:

[0015] (1) Gypsiferous salt body seismic response characteristic analysis and sensitive attribute optimization;

[0016] (2) Gypsiferous salt body main body and boundary identification;

[0017] (3) Gypsum salt top and bottom interface calibration and development thickness characterization;

[0018] (4) Gypsum salt comprehensive identification and prediction.

[0019] The further improvement of the present application is that:

[0020] In the step (1), the specific operation of the gypsum salt seismic response feature analysis is:

[0021] Based on the gypsum development of the well, the logging response characteristics of the gypsum development section are analyzed, which is distinguished from the logging response of the overlying and lower strata, and through well-seismic calibration, the seismic response characteristics of the gypsum salt in the seismic profile are analyzed.

[0022] The further improvement of the present application is that:

[0023] In the step (1), the specific operation of the sensitive attribute optimization is:

[0024] For different geological targets of gypsum salt identification, amplitude and coherent seismic attributes are extracted, point-line-surface combination is adopted, through the analysis of the through-salt body well-seismic profile and the plane attribute analysis in the salt body development time window, the sensitive attributes for identifying the main body, boundary and thickness of the gypsum salt are optimized.

[0025] The further improvement of the present application is that:

[0026] In the step (2), the amplitude skew identification of the gypsum salt main body is adopted, wherein,

[0027] The amplitude skew expression is:

[0028]

[0029] Wherein, Skew is the amplitude skew, N is the sampling point number, is the average amplitude, x i is the amplitude of the i-th sampling point, 0

[0030] The further improvement of the present application is that:

[0031] In the step (2), the boundary of the gypsum salt is identified by using coherent and edge detection attributes.

[0032] The further improvement of the present application is that:

[0033] In the step (3), the development thickness of the gypsum salt is characterized and predicted by using 90° phase rotation technology;

[0034] The calculation steps of the 90° phase rotation technology are as follows:

[0035] Firstly, the real part Re and the imaginary part Im of the signal spectrum are calculated by using FFT;

[0036] Secondly, the modulus of the signal is calculated by modular=sqtr(Re*Re+Im*Im);

[0037] The amplitude of the signal is calculated by

[0038]

[0039]

[0040] where Angle is the angle of the set rotation, P i is pi, a constant;

[0041] Finally, the signal after the phase rotation is calculated by IFFT.

[0042] Further improvements of the present application are:

[0043] The step (4), comprehensive identification and prediction of the salt body, specifically operates as:

[0044] Based on the sensitive attributes of the identification of the main body, boundary and thickness of the salt body in steps (1), (2) and (3), the sensitive attributes are superimposed, and the boundary, top and bottom interface, development thickness and spatial development condition of the salt body are comprehensively identified and predicted.

[0045] The second aspect of the present application provides a salt body identification and prediction system, the system comprises:

[0046] A seismic response characteristic analysis unit is used for analyzing the seismic response characteristics of the salt body.

[0047] A sensitive attribute optimization unit is connected with the seismic response characteristic analysis unit and is used for optimizing the sensitive attributes.

[0048] A main body and boundary identification unit is connected with the sensitive attribute optimization unit and is used for identifying the main body and boundary of the salt body.

[0049] A top and bottom interface calibration and development thickness unit is connected with the sensitive attribute optimization unit and is used for calibrating the top and bottom interface of the salt body and representing the development thickness.

[0050] A comprehensive prediction unit is connected with the main body and boundary identification unit and the top and bottom interface calibration and development thickness unit respectively and is used for comprehensively identifying and predicting the salt body.

[0051] The third aspect of the present application provides a computer readable storage medium, the computer readable storage medium stores at least one computer executable program, and the at least one program is executed by the computer to make the computer execute the steps in the above-mentioned salt body identification and prediction method.​

[0052] Compared with the prior art, the present application has the beneficial effects that:

[0053] a) Based on the sensitive attribute of the seismic data, the development scale and thickness of the gypsum rock body are predicted, compared with the limitation of the "point" understanding obtained by the drilling logging, the seismic has high plane resolution and can realize the comprehensive prediction of the longitudinal and transverse spatial development characteristics of the salt body;

[0054] b) The seismic attribute is derived from the seismic data itself, compared with the wave impedance inversion, has the advantages of economy and efficiency, and has strong practicality for the field development;

[0055] c) The 90-degree phase rotation attribute, i.e. the black double-track "upper bottom and lower top", can effectively identify the gypsum rock top and bottom interfaces and development thickness, and the top and bottom interfaces of the salt body can be quickly and effectively determined from the seismic profile, which is beneficial to the adjustment of the drilling scheme on site. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 is a step block diagram of the method of the present application;

[0057] Figure 2a is a pre-stack depth migration seismic profile of the gypsum rock passing well A#;

[0058] Figure 2b is a total energy attribute profile of the gypsum rock passing well A#;

[0059] Figure 2c is a root mean square amplitude attribute profile of the gypsum rock passing well A#;

[0060] Figure 2d is an amplitude variance attribute profile of the gypsum rock passing well A#;

[0061] Figure 2e is an average peak amplitude attribute profile of the gypsum rock passing well A#;

[0062] Figure 2f is an amplitude tortuosity attribute profile of the gypsum rock passing well A#;

[0063] Figure 3a is a coherent plane attribute extracted in the gypsum salt development section time window;

[0064] Figure 3b is a superimposed profile of the seismic data and the coherent attribute;

[0065] Figure 4 is a 90-degree phase rotation attribute profile of the gypsum salt passing well (A#, B#, C#, D#) and the depth and thickness calibration of the salt body top and bottom interfaces;

[0066] Figure 5is the 90° phase rotation attribute profile of the salt body passing through the well (E#, F#, G#) and the depth and thickness calibration of the top and bottom interfaces of the salt body;

[0067] Figure 6a is the top development and distribution of the salt body (slice 4);

[0068] Figure 6b is the middle development and distribution of the salt body (slice 6);

[0069] Figure 6c is the lower development and distribution of the salt body (slice 8);

[0070] Figure 6d is the root mean square amplitude + coherent superposition graph in the development time window of the salt body;

[0071] Figure 6e is the amplitude torsion profile of the well passing through the salt body;

[0072] Figure 6f is the 90° phase rotation attribute profile of the well passing through the salt body. DETAILED DESCRIPTION

[0073] The application will be described in further detail below with reference to the accompanying drawings:

[0074] The application is based on post-stack seismic data, and on the basis of analyzing the logging and seismic response characteristics of the salt body, the sensitive attributes are optimized for the geological target, the sensitivity of different methods in identifying the main body, boundary and thickness of the salt is determined, the planar distribution and spatial development characteristics of the salt body are determined, and then the salt body is finely characterized and predicted.

[0075] The method of the application is implemented as follows:

[0076] [Example 1]

[0077] As shown in Figure 1 , the method has the following specific steps:

[0078] (1) Analysis of the seismic response characteristics of the salt body and optimization of sensitive attributes

[0079] Based on the well analysis of the development of the salt body, the logging response characteristics of the development section of the salt body are distinguished from the logging response of the overlying and lower strata, the seismic response characteristics of the salt body in the seismic profile are analyzed through well-seismic calibration;

[0080] The characteristics of the amplitude, frequency, phase, etc. of the development position of the salt body are analyzed, the logging interpretation results are combined, the seismic reflection structure characteristics and development style of the salt body are analyzed in detail according to different thicknesses of the salt body (the seismic reflection characteristics of the salt body are analyzed according to different thicknesses of the salt rock revealed by the well), and then the foundation is laid for the optimization of different seismic attributes in the next step.

[0081] For different geological target of gypsum salt body recognition, extract amplitude class, coherent class and other seismic attributes, point line surface combination, through the analysis of well-to-well seismic profile across salt body and planar attribute analysis in salt body development time window, the sensitive attributes for recognizing the main body, boundary and thickness of gypsum salt body are optimized.

[0082] For different geological target of salt body recognition, respectively for the recognition of salt body main body, boundary and thickness, extract amplitude class, coherent class and other seismic attributes, respectively optimize the sensitive attributes for recognizing the main body of salt body, the sensitive attributes for recognizing the boundary of salt body, and the sensitive attributes for recognizing the thickness of salt body.

[0083] Through the analysis of well-to-well profile across salt body and planar attribute analysis in salt body development time window, that is, through the comparative analysis of multiple seismic attributes on profile and plane, for different geological target of salt body recognition, optimize which attributes can well identify the main body of salt body, which attributes can better identify the boundary of salt body, and which attributes can better calibrate the thickness of salt body.

[0084] Gypsum salt body seismic response characteristic analysis and sensitive attribute optimization is realized by using existing conventional methods, which will not be described here.

[0085] (2) Gypsum salt layer main body and boundary recognition

[0086] The top of gypsum salt layer in western Tahe area is the Carboniferous marker layer "double peak limestone" section (T56), T56 is a strong peak, and the top interface of gypsum salt is located at the wave trough position below the strong peak of T56. By extracting more than ten kinds of amplitude class attributes such as root mean square amplitude, total energy, amplitude variance, amplitude total, amplitude peak value and amplitude torsion, it is found that the amplitude torsion attribute has better effect in identifying the main body of gypsum salt, and the strong energy anomaly of other amplitude class attributes such as root mean square amplitude and total energy is connected with the strong energy of T56, which cannot well distinguish and identify the salt body.

[0087] Technical method of amplitude torsion for identifying the main body of salt body:

[0088] Amplitude torsion:

[0089]

[0090] Among them, Skew is the amplitude torsion, N is the number of sampling points, is the average amplitude, x i is the amplitude of the i-th sampling point, 0 < i ≤ N.

[0091] Amplitude torsion exaggerates the change and deviation of amplitude value and the degree of dispersion more than square difference amplitude, which is used to study the subtle change of amplitude value, small faults / cracks and seismic microfacies. It is suitable for areas with stable strata and small amplitude change.

[0092] Through the analysis of the seismic characteristics of the salt body development wells, the amplitude versus frequency attribute removes the influence of the strong peak energy of the "double peak limestone" of the Carboniferous System, and well represents the development characteristics of the main salt body.

[0093] For the boundary of the salt rock, the coherence and edge detection attributes are preferred to effectively identify the boundary. These attributes are selected by using the existing method, and thus will not be described here.

[0094] (3) Top and bottom interface calibration and development thickness representation of the salt body

[0095] Through the analysis of the seismic response characteristics and sensitive attributes of the salt rock, it is clear that the 90° phase rotation technology based on seismic data can effectively represent and predict the development thickness of the salt body.

[0096] Method description of 90° phase rotation technology:

[0097] Phase rotation filtering is used to change the phase angle of the data without changing the frequency range of the data. The phase rotation technology can be used to study the resolution of seismic data. In the application of seismic sedimentology, 90° phase seismic data is often used. The calculation steps are as follows:

[0098] First, calculate the real part Re and the imaginary part Im of the signal spectrum using FFT;

[0099] Second, calculate the modulus of the signal using modular=sqtr(Re*Re+Im*Im);

[0100] Calculate the amplitude angle of the signal from

[0101]

[0102]

[0103] Where Angle is the angle of rotation set, P i is π, a constant

[0104] Finally, calculate the phase-rotated signal using IFFT.

[0105] Based on the original seismic data psm, the 90° phase rotation attribute is obtained by this method. Based on the well-seismic calibration results and the profile analysis of the salt rock wells, it can be seen that the "upper bottom and lower top" of the "black double track" can well calibrate the top and bottom interfaces of the salt body and the thickness of the salt body. The drilling calibration shows that the thickness prediction accuracy is greater than 95%.

[0106] (4) Comprehensive identification and prediction of the salt body

[0107] ​The comprehensive identification and prediction is based on the sensitive attributes of the identification of the gypsum-salt body main body, boundary and thickness according to steps (1), (2) and (3), and the boundary, top and bottom interfaces, development thickness and spatial development conditions of the gypsum-salt body are comprehensively identified and predicted through the superposition of the sensitive attributes, so that the comprehensive effect of the gypsum-salt body identification is enhanced.

[0108] The stratum body is established based on two T0 equal seismic interpretation horizons (time domain seismic interpretation horizons of seismic data) of T56 to the salt body bottom, the slice number is set, and the top parallel, bottom parallel or equal proportion is set according to the contact relationship of the stratum.

[0109] The arbitrary line (that is, the connected well seismic profile of the salt body) is picked up through the salt body well, the single well, multi-well profile and plane linkage analysis, and the spatial development conditions of the salt body are displayed on the amplitude and torsion profile based on T56 from top to bottom stratum slice body, and the profile and plane linkage can clearly display the longitudinal and spatial development characteristics of the salt body.

[0110] Based on the amplitude and torsion attribute, the boundary attribute superposition and the phase rotation attribute, the boundary, top and bottom interfaces, development thickness and spatial development conditions of the salt body are comprehensively identified and predicted, so as to provide strong technical support for the adjustment of the well drilling scheme.

[0111] The slice number is set according to the target layer time window size and the fine degree of the research, for example, the slice number can be set to 10 layers.

[0112] According to the contact relationship between the two strata, the top parallel, bottom parallel or equal proportion is set, if the overlying deposition of the upper layer sedimentary sequence is mainly set to the top parallel, if the lower layer has structural deformation or erosion event caused unconformity, the bottom parallel can be set, and the equal proportion is that the upper and lower two strata do not contain the main structure or the sedimentary unconformity of the sedimentary environment, and the slice is set based on the upper and lower time window equal proportion.

[0113] The method is further explained and described below through an example.

[0114]

Example 2

[0115] Taking the gypsum-salt body below the Carboniferous marker layer "double peak limestone" in the western region of Tahe as an example, through well-seismic calibration and extraction of post-stack seismic multiple attributes, different targets for salt body identification are analyzed and optimized, and the gypsum-salt body is comprehensively identified and predicted.

[0116] Specifically, the following steps are included:

[0117] (1) Gypsum-salt body seismic response characteristic analysis and sensitive attribute optimization

[0118] Gypsum salt rock logging response characteristics: The top of the gypsum salt layer in the western region of Tahe is the "double peak limestone" section of the Carboniferous marker layer in the area, the middle is the gypsum salt rock section, and the lower part is the mudstone section. The gypsum salt layer is generally buried more than 5000 meters deep, and the thickness is generally between 30-110 meters. Compared with the upper and lower strata, the gypsum salt rock section has low GR, low density, and low speed logging response characteristics.

[0119] Gypsum salt body seismic response characteristics: Through well-to-well seismic calibration and well logging interpretation results analysis, the top interface of the gypsum salt is located at the trough position below the T56 strong wave peak, and the bottom interface is basically located at the wave peak. The gypsum salt development section has strong amplitude, high continuity, and relatively low frequency seismic reflection characteristics. In the case of large thickness (more than 80 meters), there are weak reflection, high frequency, and relatively continuous seismic reflection characteristics between the upper and lower strong continuous troughs.

[0120] Sensitive attribute optimization: Because the gypsum rock layer in the work area has strong amplitude, high continuity, and relatively low frequency seismic reflection characteristics. Therefore, amplitude-based attributes are extracted, and more than ten kinds of amplitude-based attributes such as root mean square amplitude, total energy, amplitude variance, amplitude total, amplitude peak, and amplitude torsion are analyzed. Through the analysis of the well-to-well profile of the salt body and the planar attribute analysis within the salt body development time window, the sensitive attributes for identifying the gypsum salt layer are optimized.

[0121] Through the extraction and analysis of amplitude-based and geometric-based attributes (coherence, edge detection, and lateral similarity attributes), the sensitive attributes for effectively identifying the main body and boundary of the salt body are determined.

[0122] (2) Gypsum salt body main body and boundary identification

[0123] The salt body in the western region of Tahe develops below T56. Due to the strong axis of T56 and the strong trough below it, most of the amplitude and energy-based attributes have strong energy above and below T56. Although the salt body energy is relatively strong on the profile, it is connected with the strong energy of the limestone of T56, and it is difficult to identify and distinguish the gypsum salt layer. Through sensitive attribute optimization, it is determined that the amplitude torsion has strong sensitivity in identifying the salt body.

[0124] Figures 2a to 2f It can be seen that although the root mean square amplitude, total energy, and amplitude variance have strong energy characteristics in the gypsum rock development section, they cannot be distinguished from the salt body because they are connected with the strong amplitude energy of the "double peak limestone" of T56. The amplitude torsion attribute can effectively identify the main body of the salt body and characterize the top interface of the salt body. Figure 2f

[0125] Coherent attributes: Coherent and edge detection geometric attributes can effectively identify the gypsum rock boundary, Figure 3a ​For the coherent plane attribute extracted in the development window of the salt, the plane boundary of the salt body is clear. Figure 3b For the post-stack profile of the seismic data and the coherent attribute, the longitudinal boundary of the salt body in the profile can be seen.

[0126] (3) Top and bottom interface calibration and thickness characterization of the salt body

[0127] Based on the 90° phase rotation attribute of the seismic data, the thickness of the salt body in the western part of Tahe is predicted. Based on the accurate well-to-seismic calibration, through the analysis of the single-well and multi-well continuous well profile of the salt body in the work area, combined with the thickness of the salt body interpreted from the well log, Figure 4 、 Figure 5 For the 90° phase rotation attribute profile of the well passing through the salt rock, the lower bottom interface of the upper "black track" of the "black double track" and the upper top interface of the lower "black track", the rectangular frame passing through the well is the top and bottom layering and thickness interpreted from the well log. It can be seen that the upper bottom and lower top of the "black double track" of the 90° phase rotation attribute can well characterize the top and bottom interfaces and the development thickness of the salt body. The thickness prediction error of the salt body of 19 wells in the work area with a thickness greater than 30 meters is less than 5%, that is, the prediction accuracy is greater than 95%. Therefore, the 90° phase rotation attribute can well calibrate the top and bottom interfaces and the development thickness of the salt body.

[0128] (4) Comprehensive identification and prediction of the salt body

[0129] Pick any line through the salt body well, through single-well, multi-well profile and plane linkage analysis, combined with the original seismic profile, amplitude curvature and phase rotation attribute, based on the two T0 equal seismic horizons from T56 to the bottom of the salt body, establish the stratigraphic body, set the number of slices, set whether the top is parallel, the bottom is parallel or the same proportion according to the contact relationship of the strata. The upper end of the amplitude curvature anomaly window on the profile is the development position of the top interface of the salt body. From top to bottom, the plane stratigraphic slice shows the spatial development of the salt body. At the same time, the linkage of the profile and the plane can clearly show the longitudinal and spatial development characteristics of the salt body.

[0130] Figure 6a 、 Figure 6b and Figure 6c The slice4, slice46 and slice48 in the middle plane slice show the development characteristics of the salt body at different times, and the linkage display of the slice6 in the stratigraphic body slice in the amplitude curvature profile, Figure 6e The bright white line in the middle is the longitudinal position of slice6. Based on the amplitude curvature attribute, the boundary attribute stack ( Figure 6d ) and the phase rotation attribute ( Figure 6f ), the boundary, top and bottom interface, development thickness and spatial development of the salt body are comprehensively identified and predicted, which provides strong technical support for the adjustment of the well drilling plan.

[0131] The application further provides a gypsum salt body identification and prediction system, and implementation of the system is as follows:

[0132] Example 3

[0133] The system comprises:

[0134] The seismic response characteristic analysis unit is used for analyzing the seismic response characteristics of the gypsum salt body.

[0135] The sensitive attribute optimization unit is connected with the seismic response characteristic analysis unit and is used for sensitive attribute optimization.

[0136] The main body and boundary identification unit is connected with the sensitive attribute optimization unit and is used for identifying the main body and boundary of the gypsum salt body.

[0137] The top and bottom interface calibration and development thickness unit is connected with the sensitive attribute optimization unit and is used for calibrating the top and bottom interface of the gypsum salt body and representing the development thickness.

[0138] The comprehensive prediction unit is connected with the main body and boundary identification unit and the top and bottom interface calibration and development thickness unit respectively and is used for comprehensively identifying and predicting the gypsum salt body.

[0139] The application further provides a computer readable storage medium, and implementation of the computer readable storage medium is as follows:

[0140] Example 4

[0141] The computer readable storage medium stores at least one computer executable program, and the at least one program is executed by the computer to make the computer execute the steps in the gypsum salt body identification and prediction method.

[0142] Finally, it should be noted that the above technical solutions are only one embodiment of the application, and for those skilled in the art, on the basis of the application disclosed application method and principle, various types of improvements or modifications can be easily made, and are not limited to the method described in the above embodiment, therefore, the above described method is only preferred, and does not have the meaning of limitation.

Claims

1. A method for identifying and predicting a cream salt body, characterized by, Based on the post-stack seismic data, on the basis of the analysis of the seismic response characteristics of the gypsiferous salt body, the sensitive attributes are optimized for the geological target, the sensitivity of the gypsiferous salt body, the boundary and the thickness is identified; The plane distribution and the spatial development characteristics of the gypsiferous salt body are determined, and then the gypsiferous salt body is identified and predicted; the method comprises the following steps: (1) the analysis of the seismic response characteristics of the gypsiferous salt body and the optimization of the sensitive attributes; (2) the main body of the gypsiferous salt body is identified by using the amplitude skewness, and the boundary of the gypsiferous salt body is identified by using the coherence and the edge detection attribute; the expression of the amplitude skewness is: wherein, Skew is the amplitude twist, N is the number of sampling points, is the average amplitude, x i is the amplitude of the i th sampling point, 0 i ≤ N ; (3) the top and bottom interfaces of the gypsiferous salt body are calibrated and the development thickness is characterized by using the 90° phase rotation technology; (4) the comprehensive identification and prediction of the gypsiferous salt body.

2. The method of claim 1, wherein, In the step (1), the analysis of the seismic response characteristics of the gypsiferous salt body, the specific operation is: Based on the well analysis of the gypsiferous salt development, the logging response characteristics of the gypsiferous salt development section are analyzed, which is different from the logging response of the overlying and lower strata, and the seismic response characteristics of the gypsiferous salt body in the seismic profile are analyzed through well-seismic calibration.

3. The method of claim 2, wherein, In the step (1), the optimization of the sensitive attributes, the specific operation is: For different geological targets of the gypsiferous salt body identification, the amplitude and coherence seismic attributes are extracted, the point, line and plane are combined, the sensitive attributes for identifying the main body, boundary and thickness of the gypsiferous salt body are optimized through the analysis of the well-seismic profile of the gypsiferous salt body and the plane attribute analysis in the gypsiferous salt body development window.

4. The method of claim 3, wherein, In the step (3), the calculation steps of the 90° phase rotation technology are as follows: Firstly, the real part Re and the imaginary part Im of the signal spectrum are calculated by using FFT; Secondly, the modulus of the signal is calculated by using modular=sqtr(Re*Re+Im*Im); from computing an argument of the signal; wherein Angle is the angle of the set rotation, P i is π, a constant; Finally, the phase-rotated signal is calculated by using IFFT.

5. The method of claim 4, wherein, In the step (4), the comprehensive identification and prediction of the gypsiferous salt body, the specific operation is: Based on the sensitive attributes for identifying the main body, boundary and thickness of the gypsiferous salt body in steps (1), (2) and (3), the boundary, top and bottom interfaces, development thickness and spatial development conditions of the gypsiferous salt body are comprehensively identified and predicted through the superposition of the sensitive attributes.

6. A system for identifying and predicting a pannier salt body, the system comprising: The system is used for performing the steps in the gypsiferous salt body identification and prediction method according to any one of claims 1-5, and the system comprises: a seismic response characteristic analysis unit for analyzing the seismic response characteristics of the gypsiferous salt body; a sensitive attribute optimization unit connected with the seismic response characteristic analysis unit for optimizing the sensitive attributes; a main body and boundary identification unit connected with the sensitive attribute optimization unit for identifying the main body and boundary of the gypsiferous salt body; a top and bottom interface calibration and development thickness unit connected with the sensitive attribute optimization unit for calibrating the top and bottom interfaces of the gypsiferous salt body and characterizing the development thickness; a comprehensive prediction unit connected with the main body and boundary identification unit and the top and bottom interface calibration and development thickness unit respectively for comprehensively identifying and predicting the gypsiferous salt body.

7. A computer-readable storage medium, characterized in that, The computer readable storage medium stores at least one computer executable program, and the at least one program is executed by the computer to make the computer perform the steps in the gypsiferous salt body identification and prediction method according to any one of claims 1-5.

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