Method and device for mapping underlying conglomerate structures at variable speed

Abstract

The present invention provides a variable velocity mapping method and device for underlying conglomerate structures, the method comprising: obtaining seismic data, non-seismic data and well logging data of a target area; determining the upper conglomerate segment position model of the target area according to the seismic data, non-seismic data and well logging data, and determining the underlying layer segment position model of the target area according to the seismic data and well logging data; generating the upper conglomerate segment layer velocity according to the upper conglomerate segment layer model and seismic data; inverting based on the underlying layer segment layer model and well logging data to obtain wave impedance data, and determining the underlying layer segment layer velocity according to the wave impedance data; generating a structural map of the target area according to the upper conglomerate segment layer velocity, the underlying layer segment layer velocity, the upper conglomerate segment layer model and the underlying layer segment layer model. The present invention can improve the prediction accuracy of the underlying structure morphology of conglomerate.

Description

Technical Field

[0001] The invention relates to the technical field of geophysical exploration, and in particular to a variable-speed mapping method and device for underlying conglomerate structures. Background Art

[0002] In the shallow layers of the favorable areas for oil and gas exploration in front of mountains, there are generally multi-stage conglomerate alluvial fans. The velocity of the conglomerate fans varies dramatically in the vertical and horizontal directions, and the plane thickness varies greatly, resulting in the fact that the underlying structural morphology of the conglomerate shown in the time domain seismic data usually cannot accurately reflect the real structural morphology. The existing velocity mapping method of the underlying structure of the conglomerate in front of mountains mainly uses the seismic velocity spectrum obtained in the process of seismic data processing to establish the velocity field and obtain the layer velocity under the control of the seismic horizon, and then performs variable velocity mapping after being constrained by the drilling and logging velocity.

[0003] The conventional velocity field formed by the drilling and logging velocity grid or the seismic velocity field construction and variable velocity mapping method under the control of seismic horizons have the following problems in the application of the underlying structural area of ​​piedmont conglomerate: the conglomerate stratum has chaotic reflection characteristics on the seismic, and the velocity cannot be accurately picked up during the seismic data processing. The formation velocity corresponding to the conglomerate section obtained by using the seismic velocity to establish the velocity field has low accuracy; in the underlying normal stratum section of the conglomerate deposition, the longitudinal interval of the seismic velocity spectrum points is generally 200ms to 500ms, and the layer velocity accuracy obtained by using the seismic velocity spectrum inversion is low, which cannot meet the current requirements of fine exploration; logging data generally lacks shallow data, and the velocity field formed by drilling and logging data alone cannot accurately reflect the velocity changes of shallow conglomerates; the conglomerate stratum does not have a good tracking interface on the seismic profile, and the changes in the conglomerate morphology cannot be portrayed.

[0004] However, with the gradual increase in the accuracy requirements for the underlying structure of the conglomerate during drilling deployment, "high-precision" requirements are also put forward for velocity field construction and variable-speed mapping. Summary of the invention

[0005] The invention provides a variable speed mapping method and device for underlying conglomerate structures, which can improve the prediction accuracy of the underlying conglomerate structure morphology.

[0006] In a first aspect, an embodiment of the present invention provides a method for variable velocity mapping of underlying structures in conglomerate, the method comprising: acquiring seismic data, non-seismic data and logging data of a target area; determining a stratigraphic model of an upper conglomerate section in the target area according to the seismic data, non-seismic data and logging data, and determining a stratigraphic model of an underlying layer in the target area according to the seismic data and the logging data; generating an upper conglomerate section layer velocity according to the upper conglomerate section layer model and the seismic data; performing inversion based on the underlying layer layer model and the logging data to obtain wave impedance data, and determining an underlying layer layer velocity according to the wave impedance data; generating a structural map of the target area according to the upper conglomerate section layer velocity, the underlying layer layer velocity, the upper conglomerate section stratigraphic model and the underlying layer stratigraphic model.

[0007] In a second aspect, an embodiment of the present invention further provides a variable-speed mapping device for underlying conglomerate structures, the device comprising: an information acquisition module for acquiring seismic data, non-seismic data and logging data of a target area; a layer determination module for determining a layer model of an upper conglomerate section of the target area based on the seismic data, non-seismic data and logging data, and determining a layer model of an underlying layer of the target area based on the seismic data and the logging data; an upper velocity module for generating an upper conglomerate section layer velocity based on the upper conglomerate section layer model and the seismic data; a lower velocity module for performing inversion based on the underlying layer layer model and the logging data to obtain wave impedance data, and determining the underlying layer layer velocity based on the wave impedance data; a variable-speed mapping module for generating a structural map of the target area based on the upper conglomerate section layer velocity, the underlying layer layer velocity, the upper conglomerate section layer model and the underlying layer layer model.

[0008] In a third aspect, an embodiment of the present invention further provides a computer device, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the above-mentioned variable-speed mapping method of underlying conglomerate structures is implemented.

[0009] In a fourth aspect, an embodiment of the present invention further provides a computer-readable medium having a non-volatile program code executable by a processor, wherein the program code enables the processor to execute the above-mentioned variable-speed mapping method for underlying conglomerate structures.

[0010] The embodiments of the present invention bring the following beneficial effects: the embodiments of the present invention provide a variable velocity mapping scheme for underlying structures of conglomerate, which acquires seismic data, non-seismic data and well logging data of the target area, and determines the stratigraphic model of the upper conglomerate section of the target area based on the obtained seismic data, non-seismic data and well logging data, and determines the stratigraphic model of the underlying layer section of the target area based on the seismic data and well logging data, and then generates the layer velocity of the upper conglomerate section according to the stratigraphic model of the upper conglomerate section and the seismic data; performs inversion based on the stratigraphic model of the underlying layer section and the well logging data to obtain wave impedance data, and determines the layer velocity of the underlying layer section according to the wave impedance data; thus, the structural map of the target area can be obtained through calculation. The embodiments of the present invention adopt the comprehensive analysis of non-seismic data, well logging data and seismic data to obtain an accurate stratigraphic model of the upper conglomerate section, obtain a relatively accurate stratigraphic velocity of the upper conglomerate section based on the stratigraphic model of the upper conglomerate section, and obtain the layer velocity of the underlying layer section with higher resolution by wave impedance inversion calculation, and finally obtain the structural map of the target area, thereby improving the prediction accuracy of the underlying structural morphology of the conglomerate.

[0011] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0012] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 A flow chart of a variable speed mapping method for underlying conglomerate structures provided in an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of the results of mathematically fitting the velocity of conglomerate using well logging acoustic wave data provided by an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of the morphological interpretation of a conglomerate section based on an audio frequency magnetotelluric profile provided in an embodiment of the present invention;

[0017] Figure 4A schematic diagram of a velocity profile obtained by converting data obtained by wave impedance inversion according to an embodiment of the present invention;

[0018] Figure 5 A schematic block diagram of the structure of a variable speed mapping device for underlying conglomerate structures provided by an embodiment of the present invention;

[0019] Figure 6 A structural block diagram of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] At present, there are many methods to convert seismic data in the time domain into the depth domain and then delineate favorable structural areas. In the method of implementing the underlying structure of the conglomerate, whether the thickness of the shallow conglomerate, the change of layer velocity and the fine description of the layer velocity of the middle and deep layers can be accurately implemented in the velocity field construction and variable velocity mapping process is the key to accurately implement the underlying structure of the conglomerate. Therefore, the accurate characterization of the shallow conglomerate and the fine description of the layer velocity of the middle and deep layers, and then the implementation of the morphological details of the structure, is actually the delineation of favorable structural targets.

[0022] Generally speaking, velocity field construction and velocity mapping of underlying conglomerate structures mainly consist of two parts:

[0023] 1. Use well logging, seismic and non-seismic data to describe shallow conglomerate structure and calculate conglomerate formation velocities.

[0024] The acoustic time difference data in the logging data is converted into velocity data. The acoustic time difference data AC=1 / V, where V is the acoustic wave velocity, so V=1 / AC.

[0025] When V is in m / s and AC is in μs / m, V = 1 / AC × 10 6

[0026] When V is in m / s and AC is in μs / ft, V=10 6 / (AC×0.3048)

[0027] Then, based on the velocity data obtained, approximate curve fitting is performed to determine the overall law of the vertical variation of the conglomerate in the study area. i (V i ,h i), where i = 1, 2, ..., m. Find the approximate curve And make the deviation of the approximate curve and h = f (V) minimum. The deviation of the approximate curve at point Pi i=1, 2, ..., m.

[0028] There are three common curve fitting methods:

[0029] (1) Minimize the sum of the absolute values ​​of the deviations:

[0030] (2) Minimize the maximum absolute value of the deviation:

[0031] (3) Minimize the sum of squared deviations:

[0032] Among the many methods for predicting the lithology distribution and thickness of conglomerate layers, the controlled source audio-frequency magnetotellurics (CSAMT) method is one of them. Its theoretical basis is the Maxwell equations, which include the following equations:

[0033]

[0034]

[0035]

[0036]

[0037] And D = εE

[0038] B=μH

[0039] J = σE

[0040] In the above formulas, E and D represent the electric field intensity vector and the electric induction intensity vector respectively; ε is the dielectric constant of the medium; H and B are the magnetic field intensity vector and the magnetic induction intensity vector respectively; μ is the magnetic permeability of the medium; J is the current density vector, and σ is the conductivity of the medium. In geophysical exploration, the reciprocal of σ, ρ1, is often used, which is called resistivity; ρ is the charge density.

[0041] The CSAMT method has a good effect on predicting the morphology of conglomerate, but the accuracy of the change of conglomerate velocity needs to be further improved.

[0042] This invention obtains the predicted data of gravel structure in the depth domain by inverting the CSAMT method, and converts the inversion results of the CSAMT method into time domain results through the longitudinal velocity change trend of the gravel obtained by intersecting the logging data. After being fused with the seismic profile, the shallow and medium-layer gravel structure is comprehensively interpreted in combination with the logging data.

[0043] The seismic velocity field is established based on the gravel layer data and seismic velocity spectrum obtained through comprehensive interpretation. The overall trend is controlled by geological knowledge, the velocity at the well point is controlled by the drilling depth after layer calibration, and the layer velocity in the area far from the drilling is controlled by the results of logging intersection analysis. This can better implement the velocity plane changes of the medium and shallow gravel.

[0044] 2. For the underlying normal strata of conglomerate deposits, the layer velocity of the strata can also be obtained using the wave impedance inversion technology. The advantage of this technology is that the velocity body obtained has a high resolution in both the vertical and horizontal directions.

[0045] Wave impedance inversion technology is based on three-dimensional seismic data, logging data and structural interpretation data. It uses a variety of inversion methods to obtain wave impedance data volumes with very high resolution in both the vertical and horizontal directions.

[0046] Among the many seismic impedance inversion methods, constrained sparse pulse inversion is one of the commonly used methods. The calculation process can be divided into three steps:

[0047] (1) Reflection coefficient inversion: Maximum likelihood deconvolution is used to invert the reflection coefficient. The maximum likelihood deconvolution assumes that the reflection coefficient of the formation is composed of the reflection of a larger reflection interface and a small reflection with a Gaussian background. A minimum objective function is derived:

[0048]

[0049] In the formula, R2 and N2 are the mean square values ​​of the reflection coefficient and noise, r(K) and n(K) represent the reflection coefficient and noise of the Kth sampling point, M represents the number of reflection layers, L represents the total number of samples, and λ represents the likelihood value of a given reflection coefficient. The reflection coefficient is obtained through multiple iterations.

[0050] (2) Based on the reflection coefficient calculated by maximum likelihood deconvolution and the initial impedance model, the recursive algorithm is used to invert the initial wave impedance model:

[0051]

[0052] Where Z(i) is the wave impedance value of the i-th layer, and R(i) is the reflection coefficient of the i-th layer.

[0053] (3) Perform impedance inversion in combination with well constraints: Constrained sparse pulse inversion adjusts the calculated initial impedance for each channel according to the objective function, including the adjustment of the reflection coefficient. The objective optimization function is:

[0054] F=L p (r)+λL q (sd)+α -1 L1ΔZ

[0055] In the formula, r is the reflection coefficient sequence, Δz is the difference sequence with the impedance trend, d is the seismic trace sequence, s is the synthetic seismic trace sequence, λ is the residual weight factor, α is the trend weight factor, and p and q are L-mode factors. Specifically, the first term of the right-hand formula reflects the absolute value and sum of the reflection coefficients, the second term reflects the difference between the synthetic acoustic wave record and the original seismic data, and the third term is the trend constraint term.

[0056] At present, there is no mature successful experience in establishing velocity field by wave impedance inversion. The reason is that well logging data is needed to constrain wave impedance inversion, but there is often a lack of well logging data above the middle and shallow layers, and it is impossible to obtain a complete vertical data volume.

[0057] Based on this, a variable-speed mapping method and device for underlying conglomerate structures provided in an embodiment of the present invention can adapt to the prediction of underlying conglomerate structure morphology by comprehensively utilizing a variety of seismic and geological information and improving previous methods.

[0058] To facilitate understanding of this embodiment, a variable-speed mapping method for underlying conglomerate structures disclosed in an embodiment of the present invention is first introduced in detail.

[0059] The embodiment of the present invention provides a variable speed mapping method for underlying conglomerate structures, see Figure 1 The flowchart of a variable speed mapping method for underlying conglomerate structures is shown, and the method comprises the following steps:

[0060] Step S102, obtaining seismic data, non-seismic data and well logging data of the target area.

[0061] Step S104, determining the stratigraphic model of the overlying conglomerate section of the target area based on the seismic data, non-seismic data and well logging data, and determining the stratigraphic model of the underlying layer section of the target area based on the seismic data and well logging data.

[0062] In the embodiment of the present invention, the horizon model is used to describe the structure of the horizon, and the multiple information of seismic data, non-seismic data and well logging data are comprehensively analyzed to obtain the horizon model of the upper conglomerate section, which helps to improve the structural mapping accuracy of the upper conglomerate stratum. The horizon model of the upper conglomerate section can be a three-dimensional spatial model map.

[0063] It should be noted that the underlying layer segment layer model may include only the layers of the medium-deep layer or all the layers of the medium-shallow layer and the medium-deep layer, which is determined according to actual needs and is not specifically limited in the embodiment of the present invention. The underlying layer segment layer model may be a three-dimensional spatial model diagram.

[0064] Step S106, generating the layer velocity of the upper conglomerate section according to the stratigraphic model of the upper conglomerate section and the seismic data.

[0065] In the embodiment of the present invention, a velocity field is established according to the layer model of the overlying conglomerate section and the seismic velocity spectrum in the seismic data, so that the layer velocity of the overlying conglomerate section with higher accuracy can be obtained.

[0066] Step S108, performing inversion based on the underlying layer layer model and logging data to obtain wave impedance data, and determining the underlying layer layer velocity according to the wave impedance data.

[0067] In the embodiment of the present invention, the wave impedance inversion technology can be used to obtain wave impedance data with higher resolution based on the underlying layer layer model and logging data, so as to obtain the underlying layer layer velocity with higher resolution based on the wave impedance data.

[0068] Step S110, generating a structural map of the target area according to the layer velocity of the overlying conglomerate section, the layer velocity of the underlying layer section, the stratigraphic model of the overlying conglomerate section, and the stratigraphic model of the underlying layer section.

[0069] In the embodiment of the present invention, by generating the stratigraphic model of the overlying conglomerate section and the stratigraphic model of the underlying layer for the medium-shallow layer and the medium-deep layer respectively, the layer velocity of the overlying conglomerate section with higher accuracy and the layer velocity of the underlying layer with higher resolution can be obtained, and then through variable speed mapping, a structural map of the target area with higher accuracy can be obtained.

[0070] The embodiment of the present invention provides a variable velocity mapping method for underlying conglomerate structures. The method obtains seismic data, non-seismic data and well logging data of a target area, and determines the stratigraphic model of the upper conglomerate section of the target area based on the obtained seismic data, non-seismic data and well logging data, and determines the stratigraphic model of the underlying layer section of the target area based on the seismic data and well logging data. Then, the layer velocity of the upper conglomerate section is generated according to the stratigraphic model of the upper conglomerate section and the seismic data; wave impedance data is inverted based on the stratigraphic model of the underlying layer section and the well logging data, and the layer velocity of the underlying layer section is determined according to the wave impedance data; thus, a structural map of the target area can be obtained through calculation. The embodiment of the present invention uses non-seismic data, well logging data and seismic data for comprehensive analysis to obtain an accurate stratigraphic model of the upper conglomerate section, obtains a relatively accurate stratigraphic velocity of the upper conglomerate section based on the stratigraphic model of the upper conglomerate section, and uses wave impedance inversion to calculate the layer velocity of the underlying layer section with higher resolution, and finally obtains a structural map of the target area, thereby improving the prediction accuracy of the underlying structural morphology of the conglomerate.

[0071] In order to improve the accuracy of the stratigraphic model of the upper conglomerate section, the stratigraphic model of the upper conglomerate section of the target area is determined based on seismic data, non-seismic data and well logging data, which may include the following steps:

[0072] (1) Based on the logging data, the overlying conglomerate section is divided into the surface conglomerate section and the high-speed conglomerate section.

[0073] In the embodiment of the present invention, the shallow conglomerate section is divided into two parts, surface conglomerate and high-speed conglomerate, according to the velocity change trend by using the acoustic time difference logging data. The velocity and thickness changes of the surface conglomerate section are relatively stable; the velocity and thickness changes of the high-speed conglomerate section are drastic.

[0074] (2) Determine the planar distribution of the surface conglomerate section and the high-velocity conglomerate section on non-seismic data based on the electromagnetic characteristics of the overlying conglomerate section.

[0075] In the embodiment of the present invention, the electromagnetic profile can be obtained by the CSAMT method to determine the electromagnetic characteristics of the conglomerate, and the plane distribution of the conglomerate can be preliminarily determined based on non-seismic data by combining the surface conglomerate part and the high-speed conglomerate part obtained by interpretation.

[0076] (3) Convert the plane distribution of non-seismic data into the plane distribution in the time domain.

[0077] In the embodiment of the present invention, for the conglomerate section, by comparing and optimizing the layer velocity and multiple parameters, a fitting formula for the mathematical relationship between velocity and time depth can be determined, and the plane distribution on the non-seismic data can be converted into a plane distribution in the time domain according to the fitting formula.

[0078] It should be noted that when generating the velocity of the overlying conglomerate section based on the plane distribution in the time domain, the overall trend of geological knowledge can be controlled, and the drilling depth after stratum calibration can be used to control the velocity at the well point. The above-mentioned mathematical fitting formula can be used to constrain the velocity of the conglomerate section in the area far from the drilling.

[0079] (4) The planar distribution in the time domain is integrated with the seismic data to obtain the stratigraphic model of the underlying conglomerate section in the target area.

[0080] The planar distribution in the time domain and the reflection characteristics of the conglomerate in the seismic data are confirmed respectively, and drilling calibration is performed, so as to accurately interpret the seismic data and obtain the stratigraphic model of the overlying conglomerate section in the target area.

[0081] Considering that in order to improve the accuracy of the underlying layer interval velocity, the underlying layer interval velocity can be determined according to the wave impedance data, and the following steps can be included:

[0082] The acoustic wave data of the logging data is converted into velocity data; the velocity data and the wave impedance data are fitted to obtain the fitting result; the wave impedance data is converted into the target velocity data according to the fitting result; the root mean square of the target velocity data is extracted to obtain the layer velocity of the underlying layer.

[0083] In an embodiment of the present invention, after obtaining the wave impedance data, the velocity data and the wave impedance data are fitted to obtain a mathematical relationship for describing the relationship between the velocity and the wave impedance data. Then, the wave impedance data is converted into target velocity data according to the fitting result, and the root mean square of the target velocity data is extracted to obtain the underlying layer velocity with higher accuracy.

[0084] The structural map of the target area is generated according to the layer velocity of the upper conglomerate section, the layer velocity of the lower layer section, the stratigraphic model of the upper conglomerate section and the stratigraphic model of the lower layer section, including:

[0085] A time structure map is generated based on the stratigraphic model of the overlying conglomerate section and the stratigraphic model of the underlying section; a structure map of the target area is generated based on the layer velocity of the overlying conglomerate section, the layer velocity of the underlying section and the time structure map.

[0086] In the embodiment of the present invention, the shallow conglomerate layer obtained by comprehensive interpretation of multi-information is added, and the middle and deep layers are optimized according to the velocity interface displayed by the logging data, and an interpretation structure control layer model is established to obtain a time structure map, and then the layer velocity of the overlying conglomerate section, the layer velocity of the underlying section and the time structure map are used to calculate to obtain a depth domain structure map, that is, a structure map of the target area.

[0087] The wave impedance data is obtained by inversion based on the underlying layer model and logging data, including:

[0088] The inversion control well data is determined based on the logging data; the virtual control well data is generated based on the variation trend of the conglomerate thickness; the wave impedance data is obtained by inversion based on the inversion control well data, the virtual control well data and the underlying layer segment model.

[0089] In the embodiment of the present invention, drilling and logging data with reasonable plane distribution, relatively complete logging data and high consistency with seismic comprehensive calibration are preferably selected as inversion control wells in the work area. In areas far away from the drilling wells, virtual control well data are established based on the trend of gravel thickness changes. Wave impedance inversion is performed based on the inversion control well data, the virtual control well data and the stratigraphic model of the underlying stratum to obtain wave impedance data with higher resolution.

[0090] It should be noted that wave impedance inversion can also be performed based on the inversion control well data and the underlying layer segment model to obtain wave impedance data with higher resolution. The virtual control well data can determine whether to participate in the wave impedance inversion according to actual needs, and the embodiment of the present invention does not make specific limitations on this.

[0091] The embodiment of the present invention provides a method and device for mapping the variable velocity of the underlying structure of the conglomerate, which focuses on the fine implementation of the velocity of the medium and deep formations, while taking into account the description of the shallow conglomerate velocity. The main technical measures adopted are: (1) In the study area, the drilling and logging data used for inversion control are selected, and the drilling and logging data that can be plane controlled, have relatively complete logging data, and have a high degree of consistency with the seismic comprehensive calibration are selected as the inversion control wells; (2) The shallow conglomerate layer obtained by the comprehensive interpretation of multi-information is added, and the medium and deep layers are selected according to the velocity interface displayed by the logging data, and the interpretation structure control layer model is established; (3) In the area far away from the drilling, a virtual well is established to control the shallow inversion results based on the understanding of the trend of conglomerate thickness changes.

[0092] In order to meet the needs of implementing structural morphology in the underlying structural area of ​​conglomerate, this method divides the stratum into two parts vertically according to the characteristics of the target area: one is the conglomerate section; the other is the underlying structural section of the conglomerate; and corresponding measures are taken according to the different characteristics of the two parts. The conglomerate structure is determined by combining logging data, non-seismic and seismic data, and the conglomerate section layer velocity is determined by fitting the velocity-depth relationship. The wave impedance inversion technology is used to improve the vertical and horizontal resolution of the underlying layer velocity, and a more accurate description of the velocity changes in each formation is obtained.

[0093] For a certain 3D seismic area, the newly acquired two-width and one-height 3D data fully covers an area of ​​304km 2 Non-seismic audio magnetotelluric has been deployed in the central and eastern parts of the 3D seismic zone, covering an area of ​​about 240km 2 . Several oil fields have been discovered in the three-dimensional area, and the discovered oil and gas reservoirs are mainly structural oil and gas reservoirs. The main target layers are the Jurassic Qiketai Formation, Sanjianfang Formation and Xishanyao Formation, with a stratum burial depth of 2400m to 3700m. The shallow Upper Tertiary and Quaternary (0m to 1800m) in this area are large alluvial fans mainly from the northern source. The high-speed gravel body gradually thins from north to south, and the velocity changes greatly laterally, resulting in time domain imaging that cannot reflect the true occurrence of underground strata. Therefore, the key work of oil and gas exploration in this area is to accurately implement the structural morphology, and implementing the velocity changes of the shallow gravel section is the key link to improve the accuracy of the structural map.

[0094] In this area, the structural morphology is confirmed through structural mapping, and there are two problems that need to be solved:

[0095] (1) Shallow gravel does not focus its seismic reflection energy, and the velocity picking accuracy is low during data processing, resulting in large errors in seismic velocity mapping.

[0096] Solution: Combining logging data, non-seismic data and seismic data to determine shallow gravel structure and velocity changes.

[0097] Calculation of layer velocity of conglomerate section: Based on the sonic logging curve, the underlying conglomerate is divided into two parts: surface conglomerate and high-speed conglomerate by velocity change trend. The velocity of surface conglomerate is low, but changes more dramatically, increasing sharply with increasing depth; the velocity of high-speed conglomerate is high, and changes more gently. The sonic data of multiple wells are converted into layer velocity data. After comparing the fitting results of multiple parameters, the mathematical relationship fitting formula between the layer velocity of the conglomerate formation and the time depth is determined as two sets of conglomerate velocity change quantity plates, see Figure 2 The figure shows the result of mathematical fitting of the velocity of the conglomerate using the well logging acoustic wave data. Based on this study, the electromagnetic characteristics of the two sets of conglomerates were determined in combination with the electromagnetic profile obtained by the CSAMT method, and the depth domain planar distribution of the conglomerate was preliminarily determined based on non-seismic data. Figure 3 The diagram shows the morphological interpretation of the conglomerate section based on the audio magnetotelluric profile. The interpretation results of CSMAT are converted into the time domain through the segmented intersection analysis results of the logging data of the conglomerate stratum, and are combined with the seismic data for comprehensive calibration to implement the reflection characteristics of the two sets of conglomerates in the seismic. The seismic reflection of the upper surface conglomerate is weak amplitude; the bottom boundary reflection of the lower high-speed conglomerate is medium-strong amplitude, so as to accurately interpret the seismic data and determine the plane distribution of the two sets of conglomerates in the time domain. The seismic velocity field is established using the conglomerate layer data and seismic velocity spectrum obtained by comprehensive interpretation. According to the overall trend of geological understanding, the velocity at the well point is controlled by the drilling depth after the layer calibration, and the layer velocity in the area far from the drilling is controlled by the logging intersection analysis results, which can better implement the plane change of the velocity of the medium and shallow conglomerates. The overall change of the velocity after correction is basically the same as that before correction, showing a low south and high north shape, but there are large changes in the gradient and details, and the velocity change after correction is more reasonable.

[0098] (2) The time interval of deep data in the seismic velocity spectrum is relatively large, generally 200ms-500ms. The accuracy of thin layer velocity inversion is low and cannot meet the requirements of current fine exploration.

[0099] Solution: Use seismic inversion combined with velocity field construction to determine the velocity of the underlying layer beneath the conglomerate.

[0100] Calculation of interlayer velocity of the underlying gravel layer: Drilling and logging data with reasonable plane distribution, relatively complete logging data, and high consistency with seismic comprehensive calibration are selected as inversion control wells in the work area. Shallow gravel layers obtained by comprehensive interpretation of multi-information are added. The velocity interface of the medium and deep layers is optimized based on the logging data, and an interpretation structure control layer model is established. In areas far from the drilling well, virtual control well data is established based on the trend of gravel thickness changes. The constrained sparse pulse inversion method is used for wave impedance inversion to obtain high-precision wave impedance data. The wave impedance body obtained by inversion is converted into a velocity body through the mathematical relationship between wave impedance data and layer velocity data obtained by the multi-well intersection method, see Figure 4 The velocity profile diagram of the data converted by wave impedance inversion is shown in the figure, where the multiple black vertical lines in the figure indicate the location of the well. The interlayer data of the converted velocity body is extracted to obtain the layer velocity of each set of formations. The velocity data obtained by inversion has clear vertical velocity variation law, reasonable plane variation law, accurate detail description and high precision.

[0101] Through the implementation of this technology, multiple sets of target layer structural morphologies have been implemented. After implementation, the actual drilling results of new wells have an error of less than 0.5% compared with the predicted layer positions.

[0102] The present invention also provides a variable speed mapping device for underlying conglomerate structures, see Figure 5 The structure block diagram of the variable speed mapping device for the underlying conglomerate structure shown in FIG. 1 includes:

[0103] The information acquisition module 51 is used to acquire seismic data, non-seismic data and logging data of the target area; the layer determination module 52 is used to determine the layer model of the upper conglomerate section of the target area according to the seismic data, non-seismic data and logging data, and determine the layer model of the underlying layer section of the target area according to the seismic data and logging data; the upper velocity module 53 is used to generate the layer velocity of the upper conglomerate section according to the layer model of the upper conglomerate section and the seismic data; the underlying velocity module 54 is used to perform inversion based on the layer model of the underlying layer section and the logging data to obtain wave impedance data, and determine the layer velocity of the underlying layer section according to the wave impedance data; the variable speed mapping module 55 is used to generate a structural map of the target area according to the layer velocity of the upper conglomerate section, the layer velocity of the underlying layer section, the layer model of the upper conglomerate section and the layer model of the underlying layer section.

[0104] In one embodiment, the stratigraphic information determination module is specifically used to: divide the upper conglomerate section into a surface conglomerate part and a high-speed conglomerate part according to the logging data; determine the planar distribution of the surface conglomerate part and the high-speed conglomerate part on the non-seismic data according to the electromagnetic characteristics of the upper conglomerate section; convert the planar distribution on the non-seismic data into a planar distribution in the time domain; and fuse the planar distribution in the time domain with the seismic data to obtain a stratigraphic model of the upper conglomerate section in the target area.

[0105] In one embodiment, the underlying velocity module is specifically used to: convert the acoustic wave data of the logging data into velocity data; fit the velocity data and the wave impedance data to obtain a fitting result; convert the wave impedance data into target velocity data according to the fitting result; extract the root mean square of the target velocity data to obtain the underlying layer interval velocity.

[0106] In one embodiment, the variable speed mapping module is specifically used to: generate a time structural map according to the stratigraphic model of the upper conglomerate section and the stratigraphic model of the lower layer section; generate a structural map of the target area according to the layer velocity of the upper conglomerate section, the layer velocity of the lower layer section and the time structural map.

[0107] In one embodiment, the underlying velocity module is specifically used to: determine the inversion control well data according to the logging data; generate virtual control well data according to the conglomerate thickness change trend; and perform inversion based on the inversion control well data, the virtual control well data and the underlying layer segment stratigraphic model to obtain the wave impedance data.

[0108] The embodiment of the present invention also provides a computer device, see Figure 6 The computer device shown in the schematic block diagram includes a memory 61 and a processor 62. The memory stores a computer program that can be run on the processor. When the processor executes the computer program, the steps of any of the above methods are implemented.

[0109] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working process of the computer device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0110] An embodiment of the present invention further provides a computer-readable medium having a non-volatile program code executable by a processor, wherein the program code enables the processor to execute the steps of any one of the above methods.

[0111] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0112] The present invention is described with reference to flowcharts and / or block diagrams of methods and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. 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.

[0113] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0114] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0115] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A variable speed mapping method for underlying conglomerate structures, characterized in that: include: Obtain seismic data, electromagnetic data and well logging data in the target area; Determine the stratigraphic model of the upper conglomerate section of the target area according to the seismic data, the electromagnetic data and the well logging data, and determine the stratigraphic model of the lower layer section of the target area according to the seismic data and the well logging data; Generate the layer velocity of the upper conglomerate section according to the stratigraphic model of the upper conglomerate section and the seismic data; Inverting the underlying layer interval model and the logging data to obtain wave impedance data, and determining the underlying layer interval velocity according to the wave impedance data; Generate a structural map of the target area according to the layer velocity of the upper conglomerate section, the layer velocity of the lower layer section, the stratigraphic model of the upper conglomerate section and the stratigraphic model of the lower layer section; Wherein, determining the stratigraphic model of the upper conglomerate section of the target area according to the seismic data, the electromagnetic data and the logging data includes: dividing the upper conglomerate section into a surface conglomerate part and a high-velocity conglomerate part according to the logging data; determining the plane distribution of the surface conglomerate part and the high-velocity conglomerate part on the electromagnetic data according to the electromagnetic characteristics of the upper conglomerate section; converting the plane distribution on the electromagnetic data into a plane distribution in the time domain; respectively confirming the plane distribution in the time domain and the reflection characteristics of the conglomerate in the seismic data, performing drilling calibration, and interpreting the seismic data to obtain the stratigraphic model of the upper conglomerate section of the target area; Wherein, determining the underlying layer interval layer velocity according to the wave impedance data includes: converting the acoustic wave data of the logging data into velocity data; fitting the velocity data and the wave impedance data to obtain a fitting result; converting the wave impedance data into target velocity data according to the fitting result; extracting the root mean square of the target velocity data to obtain the underlying layer interval layer velocity; Wherein, inversion is performed based on the underlying layer segment stratigraphic model and the logging data to obtain the wave impedance data, including: determining the inversion control well data based on the logging data; generating virtual control well data based on the conglomerate thickness change trend; and obtaining the wave impedance data by inversion based on the inversion control well data, the virtual control well data and the underlying layer segment stratigraphic model.

2. The variable speed mapping method for underlying conglomerate structures according to claim 1, characterized in that: Generating a structural map of the target area according to the layer velocity of the upper conglomerate section, the layer velocity of the lower layer section, the stratigraphic model of the upper conglomerate section and the stratigraphic model of the lower layer section, including: Generate a temporal structural map according to the stratigraphic model of the overlying conglomerate section and the stratigraphic model of the underlying section; A structural map of the target area is generated according to the layer velocity of the overlying conglomerate section, the layer velocity of the underlying layer section and the time structural map.

3. A variable speed mapping device for underlying conglomerate structures, characterized in that: include: Information acquisition module, used to obtain seismic data, electromagnetic data and well logging data in the target area; A layer determination module, used to determine the layer model of the upper conglomerate section of the target area according to the seismic data, the electromagnetic data and the well logging data, and to determine the layer model of the lower layer section of the target area according to the seismic data and the well logging data; An overburden velocity module, used for generating an overburden conglomerate interval layer velocity according to the overburden conglomerate interval layer model and the seismic data; An underlying velocity module, used for inverting the underlying layer interval model and the logging data to obtain wave impedance data, and determining the underlying layer interval velocity according to the wave impedance data; A variable speed mapping module is used to generate a structural map of the target area according to the layer velocity of the upper conglomerate section, the layer velocity of the lower layer section, the stratigraphic model of the upper conglomerate section and the stratigraphic model of the lower layer section; Wherein, the layer determination module is specifically used for: Dividing the overlying conglomerate section into a surface conglomerate portion and a high-speed conglomerate portion according to the well logging data; Determining the planar distribution of the surface conglomerate portion and the high-speed conglomerate portion on the electromagnetic data according to the electromagnetic characteristics of the overlying conglomerate section; Converting the plane distribution of the electromagnetic data into a plane distribution in the time domain; Respectively confirm the plane distribution of the time domain and the reflection characteristics of the conglomerate in the seismic data, perform drilling calibration, interpret the seismic data, and obtain the stratigraphic model of the overlying conglomerate section in the target area; The underlying velocity module is specifically used to: convert the acoustic wave data of the logging data into velocity data; fit the velocity data and the wave impedance data to obtain a fitting result; convert the wave impedance data into target velocity data according to the fitting result; extract the root mean square of the target velocity data to obtain the underlying layer interval velocity; The underlying velocity module is specifically used to: determine the inversion control well data according to the logging data; generate virtual control well data according to the trend of conglomerate thickness changes; and obtain wave impedance data by inversion based on the inversion control well data, virtual control well data and the underlying layer segment model.

4. A computer device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to claim 1 or 2 are implemented.

5. A computer-readable medium having a non-volatile program code executable by a processor, characterized in that: The program code enables the processor to execute the method of claim 1 or 2.

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