Well-free seismic calibration method and well-free seismic calibration method for intra-basin super-deep ancient strata

Abstract

The present application provides a well-free seismic calibration method and a well-free seismic calibration method for intra-basin super-deep old strata, comprising: (1) determining the lithology of outcrop strata in the study area; (2) obtaining the lithology parameters of the lithology of the outcrop strata in the study area; (3) making a virtual well synthetic record based on the lithology parameters; and (4) determining a seismic interpretation scheme for the well-free section in the study area according to the virtual well synthetic record. The present application can effectively obtain a seismic interpretation scheme for strata (especially super-deep old strata) without drilling a well, thereby achieving the purpose of cost reduction and efficiency improvement.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of geological exploration, in particular to a borehole-free seismic calibration method and a borehole-free seismic calibration method for intra-basin super-deep old strata. BACKGROUND

[0002] With the deepening of geological researches on Tarim Basin and the like, oil and gas exploration is continuously pushed to super-deep old strata. However, the research on super-deep old strata is faced with problems such as serious shortage of drilling data, great difficulty in seismic horizon interpretation, and the like. In particular, for Nanhua-Sinian strata, there is almost no complete drilling columnar section and corresponding drilling logging curve. Therefore, the method for seismic calibration using drilling logging curve in the prior art cannot be implemented in borehole-free areas.

[0003] Some researches in the prior art also point out that the borehole-free seismic calibration can be realized by using field outcrop strata data to perform qualitative seismic-geological analogy. However, the seismic-geological analogy method has strong multi-solution and poor accuracy. In particular, when applied to the geological structure interpretation of super-deep old strata, the obtained result has low reliability, which often leads to great difference between the seismic interpretation result and the actual seismic interpretation obtained from drilling. SUMMARY

[0004] The present application provides a borehole-free seismic calibration method and a borehole-free seismic calibration method for intra-basin super-deep old strata, to at least solve the problem of low accuracy of seismic interpretation result, in particular, for borehole-free intra-basin super-deep old strata.

[0005] The present application provides a borehole-free seismic calibration method, comprising: (1) determining the lithology of outcrop strata in the research area; (2) obtaining lithology parameters of the lithology of outcrop strata in the research area; (3) making a virtual well synthetic record based on the lithology parameters; and (4) determining a seismic interpretation scheme for borehole-free sections in the research area according to the virtual well synthetic record.

[0006] According to an embodiment of the present application, the lithology parameters include rock density and acoustic time difference, a wave impedance value is calculated according to the formula wave impedance value = rock density / acoustic time difference, and the virtual well synthetic record is made using the wave impedance value.

[0007] According to an embodiment of the present application, in step (2), the manner of obtaining the lithology parameter of the lithology of the outcrop formation in the study area comprises: collecting rock samples of the outcrop formation in the study area, detecting and analyzing the rock samples to obtain the lithology parameter of the lithology of the outcrop formation in the study area; or, establishing a lithology-lithology parameter corresponding standard representing the lithology parameters corresponding to different lithologies, and determining the lithology parameter of the lithology of the outcrop formation in the study area according to the lithology of the outcrop formation in the study area determined in step (1) and the lithology-lithology parameter corresponding standard; or, the lithology parameter of the lithology of the outcrop formation in the study area is obtained from measured lithology parameters of drilled wells, and the measured lithology parameters of the drilled wells include measured lithology parameters of a drilled well section in the study area and / or measured lithology parameters of drilled wells in a neighboring area of the study area.

[0008] According to an embodiment of the present application, the lithology comprises at least one of mudstone, salt rock, quartzite, gneiss, limestone, granite, gypsum rock, pyroxene rock or dolomite.

[0009] According to an embodiment of the present application, the depth of the drilled well section in the study area and / or the drilled wells in the neighboring area of the study area is not greater than 6000 meters.

[0010] According to an embodiment of the present application, the measured lithology parameters of the drilled wells are selected from logging values of drilled wells within a range of 100 km in radius centered on the study area.

[0011] According to an embodiment of the present application, the virtual well synthetic record is made by using Landmark analysis software.

[0012] According to an embodiment of the present application, step (2) comprises: obtaining a seismic interpretation scheme of the study area by seismic forward modeling based on the virtual well synthetic record; wherein the seismic forward modeling comprises two-dimensional forward modeling.

[0013] According to another aspect of the present application, a method for calibrating a well-free seismic survey of an ultra-deep ancient formation in a basin is provided, comprising: (1') determining the lithology of an outcrop formation at a basin margin of a study area; (2') obtaining a lithology parameter of the lithology of the outcrop formation at the basin margin of the study area, wherein the lithology parameter of the lithology of the outcrop formation at the basin margin of the study area is obtained from measured lithology parameters of drilled wells, and the measured lithology parameters of the drilled wells are selected from logging values of drilled wells within a range of 100 km in radius centered on the study area; (3') making a virtual well synthetic record based on the lithology parameter; and (4') determining a seismic interpretation scheme of an ultra-deep ancient formation in the study area according to the virtual well synthetic record.

[0014] According to an embodiment of the present application, the ultra-deep ancient formation in the basin comprises a Nanhua-Sinian formation, and / or the ultra-deep ancient formation in the basin partially continues to a metamorphic rock basement structure of Archean-Middle Proterozoic.

[0015] The well-free seismic calibration method provided by the present application can effectively obtain a seismic interpretation scheme including seismic calibration and horizon tracking of strata without drilling, reduces the drilling workload, greatly saves the drilling cost, achieves the purpose of reducing cost and increasing benefit, and can be applied to seismic calibration and horizon tracking of super-deep old strata in a well-free area, greatly improves the accuracy of seismic interpretation of super-deep old strata in a well-free area, and provides important technical support and geological basis for oilfield super-deep field geological understanding and risk exploration research, favorable zone evaluation and well site demonstration, and has strong practicability. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a histogram of the strata rock density parameters of nine main lithologies of the pre-Ordovician system;

[0017] Figure 2 is a histogram of the strata interval transit time parameters of nine main lithologies of the pre-Ordovician system;

[0018] Figure 3 is a histogram of the strata wave impedance values of nine main lithologies of the pre-Ordovician system;

[0019] Figure 4 is a pre-Cambrian wave impedance (left side) and a synthetic record (right side) map of the outcrop in the northern area of the Kuruktag in Example 1;

[0020] Figure 5 is a seismic profile map interpreted by the outcrop synthetic record in the northern area of the Kuruktag in Example 1;

[0021] Figure 6 is a drilling curve (left side) and a seismic interpretation result (right side) map of Well YL1 in Test Example 1;

[0022] Figure 7 is a strata interpretation result map of the area where Well YL1 is located in Test Example 1;

[0023] Figure 8 is a seismic interpretation result map of the area where Well YL1 is located obtained in Reference Example 1;

[0024] Figure 9 is a splicing comparison diagram of the strata interpretation results of the area where Well YL1 is located in Test Example 1 and Example 1. DETAILED DESCRIPTION

[0025] In order for those skilled in the art to better understand the scheme of the present application, the present application is further described in detail as follows.

[0026] The well-free seismic calibration method provided by the present application comprises the following steps: (1) determining the lithology of outcrop strata in a study area; (2) obtaining lithology parameters of the lithology of the outcrop strata in the study area; (3) making a virtual well synthetic record based on the lithology parameters; and (4) determining a seismic interpretation scheme for a well-free section in the study area according to the virtual well synthetic record.

[0027] In some embodiments, the lithology parameters comprise rock density and acoustic travel time, and the wave impedance value is calculated according to the formula: wave impedance value = rock density / acoustic travel time, and the virtual well synthetic record is made by using the wave impedance value.

[0028] Different strata have different lithologies, and their rock densities are also different, which leads to different propagation speeds of acoustic waves in the strata. Therefore, the present application selects rock density and acoustic travel time as the lithology parameters of each stratum. The rock density value (DEN) of the structure of different lithologies has a certain degree of distinction, and the acoustic travel time value (DT) also has a certain degree of distinction. However, the rock density and / or acoustic travel time of some lithologies are overlapped and crossed, and it is difficult to distinguish them obviously. Research shows that the wave impedance values corresponding to different lithologies, which are calculated by dividing the rock density corresponding to each lithology by the acoustic travel time, have obvious differences and good distinction. Therefore, the wave impedance value can be used as a typical parameter for characterizing different lithologies, and the lithology of different strata can be converted into the wave impedance value of the stratum through data processing and calculation, and then the wave impedance value is used for seismic profile synthetic record to calibrate and interpret the stratum. Therefore, in some preferred embodiments, the lithology parameters comprise rock density and acoustic travel time, and the wave impedance value is calculated according to the formula: wave impedance value = rock density / acoustic travel time. In specific implementation, the rock density and acoustic travel time of the outcrop strata in the study area can be obtained, and then the wave impedance value is calculated.

[0029] Specifically, when seismic waves propagate in a medium, the ratio of the pressure acting on a certain area to the mass point flow (i.e. the product of the area and the mass point vibration velocity) vertically passing through the area per unit time has the meaning of resistance, which is called wave impedance, and its value is equal to the product of the medium density and the wave velocity, that is, the wave impedance value is the product of the acoustic wave velocity in the rock and the rock density, and the acoustic travel time is the inverse of the acoustic wave velocity. Therefore, the wave impedance value = rock density / acoustic travel time, which can indicate the disturbance force required for the moving rock mass point to produce unit velocity when the stress wave propagates in the rock mass, and can also reflect the resistance of the rock to momentum transmission. In the technical scheme of the present application, it is found that the wave impedance values of various single types of lithologies have good distinction by calculating the wave impedance value from the rock density value and the acoustic travel time value of the lithology parameters.

[0030] In the present application, the ways of obtaining the lithology parameters of the lithology of the outcrop strata of the study area include but are not limited to the following ways: (A) collecting rock samples of the outcrop strata of the study area, detecting and analyzing the rock samples (i.e. taking rock samples from the outcrop strata of the study area for detection), obtaining the lithology parameters of the lithology of the outcrop strata of the study area, and relatively speaking, this way can more accurately obtain the lithology parameters of the lithology of the outcrop strata of the study area; (B) establishing a lithology-lithology parameter corresponding standard representing different lithology corresponding lithology parameters, determining the lithology parameters of the lithology of the outcrop strata of the study area according to the lithology of the outcrop strata of the study area determined in step (1) and the lithology-lithology parameter corresponding standard (determining the lithology parameters of the lithology of the outcrop strata of the study area according to the lithology parameter empirical value of the lithology of the outcrop strata of the study area); (C) the lithology parameters of the lithology of the outcrop strata of the study area come from the measured lithology parameters of the drilled wells, and the measured lithology parameters of the drilled wells include the measured lithology parameters of the drilled well section of the study area and / or the measured lithology parameters of the drilled well of the adjacent area of the study area.

[0031] By statistically analyzing the lithology data of the Cambrian to pre-Nanhua metamorphic rock basement, the following lithology composition is determined: the main lithology of the pre-Ordovician strata includes nine kinds of mudstone, salt rock, quartzite, gneiss, limestone, granite, gypsum rock, pyroxene rock and dolomite, among which the lithology of the Cambrian strata is mainly dolomite, with gypsum rock, salt rock and mudstone; the lithology of the Sinian strata is mainly dolomite and sandy mudstone; the lithology of the Nanhua strata is mainly sandy mudstone, with volcanic rocks; the lithology of the pre-Nanhua strata is mainly metamorphic rock, with local development of volcanic rocks. The above-mentioned lithology generally includes but is not limited to at least one of mudstone, salt rock, quartzite, gneiss, limestone, granite, gypsum rock, pyroxene rock or dolomite, i.e. the strata of the study area can be composed of pure lithology, or can be composed of multiple lithologies.

[0032] In some embodiments, nine typical single types of lithology (i.e. mudstone, salt rock, quartzite, gneiss, limestone, granite, gypsum rock, pyroxene rock or dolomite) are extracted from numerous complex strata compositions, and the arithmetic mean is obtained by a large amount of historical data to obtain the lithology parameters corresponding to various types of lithology. Take mudstone as an example, the rock density corresponding to mudstone is obtained by calculating the average value of a large amount of historical data of rock density of mudstone, and the acoustic travel time corresponding to mudstone is obtained by calculating the average value of a large amount of historical data of acoustic travel time of mudstone. Thus, the lithology-lithology parameter corresponding standard of the lithology parameters corresponding to different lithology is established, and through the lithology-lithology parameter corresponding standard, the corresponding lithology parameters can be easily consulted according to the lithology of the strata.

[0033] Specifically, the lithology-lithology parameter corresponding standard includes a lithology-lithology density corresponding standard ( Figure 1 ) and a lithology-acoustic travel time corresponding standard ( Figure 2 ). Figure 1As shown, the rock density of mudstone is 2.28 g / cm 3 , the rock density of salt rock is 2.02 g / cm 3 , the rock density of quartzite is 2.59 g / cm 3 , the rock density of gneiss is 2.75 g / cm 3 , the rock density of limestone is 2.69 g / cm 3 , the rock density of granite is 2.67 g / cm 3 , the rock density of gypsum rock is 2.90 g / cm 3 , the rock density of pyroxene rock is 2.98 g / cm 3 , and the rock density of dolomite is 2.86 g / cm 3 ; as shown in the accompanying Figure 2 , the acoustic travel time of mudstone is 78.0 μs / ft, the acoustic travel time of salt rock is 70.0 μs / ft, the acoustic travel time of quartzite is 63.0 μs / ft, the acoustic travel time of gneiss is 61.0 μs / ft, the acoustic travel time of limestone is 51.0 μs / ft, the acoustic travel time of granite is 50.0 μs / ft, the acoustic travel time of gypsum rock is 51.5 μs / ft, the acoustic travel time of pyroxene rock is 50.0 μs / ft, and the acoustic travel time of dolomite is 47.5 μs / ft.

[0034] In addition, according to the wave impedance value = rock density / acoustic travel time, the wave impedance value corresponding to each lithology can be converted from the rock density ( Figure 1 ) and the acoustic travel time ( Figure 2 ) corresponding to each lithology, and a lithology-wave impedance value corresponding standard ( Figure 3 ) is formed. After determining the outcrop stratum lithology of the study area, the wave impedance value is consulted according to the lithology-wave impedance value corresponding standard. As shown in the accompanying Figure 3 , the wave impedance value of mudstone is 8900 g / cm 3 ·m / s, the wave impedance value of salt rock is 8800 g / cm 3 ·m / s, the wave impedance value of quartzite is 12500 g / cm 3 ·m / s, the wave impedance value of gneiss is 13700 g / cm 3 ·m / s, the wave impedance value of limestone is 16000 g / cm 3 ·m / s, the wave impedance value of granite is 16300 g / cm 3 ·m / s, the wave impedance value of gypsum rock is 17200 g / cm 3 ·m / s, the wave impedance value of pyroxene rock is 18200 g / cm 3 ·m / s, and the wave impedance value of dolomite is 18400 g / cm 3m / s; in calculating the wave impedance value, the unit of acoustic wave time difference needs to be converted, wherein 1 μs is equal to 10 -6 s, and 1 ft is equal to 0.3048 m.

[0035] Specifically, when the lithology of the outcrop stratum is a single type of lithology, the wave impedance value can be directly consulted according to the above-mentioned lithology-lithology parameter corresponding standard or the lithology-wave impedance value corresponding standard; if the lithology of the outcrop stratum is mixed lithology (i.e. not a single type of lithology, for example, sandstone and mudstone, which is a mixed phase of limestone and dolomite), the composition structure of the lithology needs to be determined, the types of the lithology and the percentage of each lithology are determined, then the lithology parameters of each lithology are weighted and averaged according to the percentage of each lithology, the lithology parameters and the wave impedance value of the outcrop stratum are calculated; and for the lithology with very complex composition structure, if it is difficult to decompose it into various single types of lithology, the lithology parameters of the outcrop stratum can be obtained through the above-mentioned method (A) (i.e. collecting rock samples of the outcrop stratum in the field, and accurately testing the lithology parameters in the laboratory).

[0036] It is found that there is a certain correlation between the stratum structures in the same research area, the outcrop stratum is due to stratum movement, and the stratum deposition structure is similar or the same to the underground stratum structure, therefore, the lithology parameters of the outcrop stratum are used to calculate the wave impedance value, the wave impedance value is assigned to the seismic analysis software to run, the synthetic record of the simulation well (i.e. the above-mentioned virtual well synthetic record) is obtained, and the underground stratum is interpreted according to the simulation well synthetic record (the simulation well is a virtual well, and does not need to be actually drilled to sample and draw a drilling curve), in the process, the outcrop lithology column chart which is real and reliable is converted into a simulation well, the drilling workload is reduced, the drilling cost is greatly saved, and the effect of reducing cost and increasing benefit is achieved.

[0037] In addition, as in the manner (C) above, the lithology parameters used to make the virtual well synthetic record can also be obtained from the measured lithology parameters of the adjacent area (for example, the adjacent block of the study area or the adjacent horizon of the well-free section of the study area (for example, the drilled section of the study area)) of the study area. Generally, the adjacent area (the adjacent block or the adjacent horizon) of the well-free section of the study area has substantially the same or similar lithology as the formation structure of the study area, and thus the logging values (i.e., the lithology parameters obtained from the actual drilling) of the adjacent block or the adjacent horizon can be selected as the lithology parameters used to make the virtual well synthetic record. Specifically, the measured lithology parameters of the drilled section of the study area can be the lithology parameters measured by the actual drilling in the shallow layer of the study area (the well-free section of the study area is located below the drilled section (the shallow layer)), and the measured lithology parameters of the drilled well of the adjacent area of the study area are the lithology parameters measured by the actual drilling in the adjacent area of the study area. In specific implementation, the measured lithology parameters of the drilled well can be directly obtained from the logging values of the drilled well of the drilled section of the study area or the adjacent area of the study area. In some specific embodiments, the measured lithology parameters of the drilled well are selected from the logging values of the drilled well within a range of 100 km from the center of the study area, that is, the logging values of the drilled well within a range of 100 km from the center of the study area are selected to obtain the lithology parameters, and then the wave impedance values are obtained. Alternatively, the drilling can be performed within a range of 100 km from the center of the study area to measure the lithology parameters of the drilled well and obtain the wave impedance values. The process of obtaining the measured lithology parameters by drilling can be a conventional process in the art, which will not be described herein.

[0038] In specific implementation, the formation can be divided according to the lithology composition, for example, the areas with substantially the same lithology composition can be divided into a formation division, and each formation division can be used as a study area to obtain the seismic interpretation scheme of the well-free section of the study area by the above process. The adjacent area (the adjacent block) of the study area is a region extending 100 km from the boundary of the study area. For example, if the study area is a region with a radius of 200 km, the measured lithology parameters of the drilled well can be selected from the logging values of the drilled well within a range of 300 km from the center of the study area.

[0039] The drilled section of the study area and the drilled well of the adjacent area of the study area are generally shallow wells, and the depth is usually not greater than 6000 meters. The formation with a depth greater than 6000 meters is generally a well-free area without actual drilling. The present application can particularly obtain the seismic interpretation scheme of the formation of the ultra-deep well-free area (the well-free section of the study area (i.e., the undrilled section)) with a depth greater than 6000 meters, but is not limited thereto. For example, when there is no drilling in the study area, the seismic interpretation scheme of the study area can also be obtained by the method of the present application.

[0040] Specifically, when the study area has drilled and undrilled sections, the measured lithology parameters of the drilled section and / or the measured lithology parameters of the drilled well in the adjacent area of the study area can be obtained, and the above-mentioned virtual well synthetic record is made according to the obtained lithology parameters; when the study area is undrilled (i.e. the study area is entirely an undrilled section without drilled sections), the lithology parameters of the outcrop formation of the study area and / or the measured lithology parameters of the drilled well in the adjacent area of the study area can be obtained, and the above-mentioned virtual well synthetic record is made according to the obtained lithology parameters.

[0041] In step (2), the wave impedance value is assigned as the logging (virtual well) result of the outcrop profile to make the virtual well synthetic record. In the present application, the conventional seismic analysis software can be used to make the synthetic record, for example, in some embodiments, the Landmark analysis software is used to make the virtual well synthetic record, and in the specific operation, the wave impedance value of the outcrop formation determined in step (2) can be input into the assignment area (SynTool module) of the logging parameter wave impedance value of the analysis software, and used as the drilling parameter to run the software, so that the virtual well synthetic record (or the simulated well synthetic record) can be generated.

[0042] Step (2) can include obtaining the seismic interpretation scheme of the study area through seismic forward modeling based on the virtual well synthetic record. Specifically, after the virtual well synthetic record is generated, the seismic data interpretation can be performed through seismic forward modeling. The seismic forward modeling is to establish the underground geological model (or the seismic model) by using the existing logging / drilling data, to calculate the seismic record of the established geological model through a certain mathematical method according to the propagation principle of seismic waves in the underground medium, that is, the seismic forward modeling is the process of obtaining the corresponding seismic response according to the known (or designed) mathematical and physical model or geological model. The one-dimensional model forward modeling is to calculate the synthetic seismic trace (see the synthetic seismic record), the two-dimensional forward modeling is to calculate the synthetic seismic profile, and the three-dimensional forward modeling is to obtain the theoretical three-dimensional data body. Generally, the seismic model can be designed according to the geological analysis results of the well data of the actual drilling, or obtained from the seismic data interpretation results. In the implementation process of the present application, the seismic forward modeling can include two-dimensional forward modeling, and in the specific operation, the seismic profile similar to the formation of the virtual well synthetic record can be selected, and the seismic horizon calibration, interpretation tracking and the like of the well-free area are performed in combination with the virtual well synthetic record to obtain the seismic interpretation scheme of the study area. For example, in some embodiments, the Sinian and Nanhua systems are included in the virtual well synthetic record, and then the seismic profile with the Sinian and Nanhua systems (i.e. the seismic profile similar to the formation of the virtual well synthetic record) can be selected, and the seismic interpretation of the well-free area is performed in combination with the virtual well synthetic record. The seismic profile similar to the formation of the virtual well synthetic record can be obtained according to the conventional method in the art, for example, it can be selected from the seismic data of the study area.

[0043] An embodiment of the present application provides a method for calibrating a basin-in super-deep old stratum without a well, comprising: (1') determining the lithology of a basin-margin outcrop stratum of a study area; (2') obtaining a lithology parameter of the lithology of the basin-margin outcrop stratum of the study area, the lithology parameter of the lithology of the basin-margin outcrop stratum of the study area being from a measured lithology parameter of a drilled well, the measured lithology parameter of the drilled well being selected from a logging value of a drilled well within a range of 100 km with the study area as a center; (3') synthesizing a virtual well record based on the lithology parameter; and (4') determining a seismic interpretation scheme of a super-deep old stratum of the study area according to the virtual well record.

[0044] Generally, the depth of the super-deep old stratum is not less than 6000 meters, for example, 6000-20000 meters or 6000-10000 meters. The drilled well is a middle-shallow well with a depth generally not more than 6000 meters.

[0045] The method for calibrating without a well is especially suitable for seismic interpretation / calibration of Nanhua-Sinian paleogeography and paleostructure, that is, the basin-in super-deep old stratum can include Nanhua-Sinian strata, and a good calibration effect can be achieved. In addition, the basin-in super-deep old stratum can be partially continued to Archean-Middle Proterozoic metamorphic rock basement structure.

[0046] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in combination with specific examples. Obviously, the described examples are a part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0047] Example 1

[0048] In the north-south direction of the north area of the Kuruktag in the Tarim Basin, there is a no-well area (about 200 km x 200 km), and the following process is used to calibrate the seismic data of the no-well area:

[0049] Firstly, the lithology of the outcrop stratum in the north area of the Kuruktag is determined to be the lithology of the Precambrian stratum, and then the corresponding lithology parameter is obtained, the wave impedance value is calculated, and the wave impedance value is taken as the drilling parameter of the outcrop stratum, the analysis is performed by using the Landmark software, and the obtained simulation well synthetic record is as shown in Figure 4 The seismic profile interpreted from the outcrop synthetic record obtained by running the Landmark software is as shown in Figure 5 The location and direction of the point corresponding to the synthetic record in the Tarim Basin are as shown by the round dot and the line in the lower right corner of Figure 5 , wherein T∈ represents the bottom boundary of the Cambrian stratum, TZ represents the bottom boundary of the Sinian stratum, and TNh represents the bottom boundary of the Nanhua stratum.

[0050] Combination Figure 4 and Figure 5 The process of conducting seismic calibration and obtaining a seismic interpretation scheme mainly involves: knowing that the bottom of the Cambrian strata is the top of the Sinian strata, based on... Figure 4 The synthetic record of the Sinian system on the right side is confirmed. Figure 5 The bottom of the Sinian system is used to determine the top of the Nanhua system (the bottom of the Sinian system is the top of the Nanhua system); then according to... Figure 4 The synthetic record of the Nanhua system on the right side is confirmed. Figure 5 The foundation of the Zhongnan Hua Group; among them, in Figure 5 After determining the bottom or top of each stratum, solid lines are drawn extending left and right from the dashed lines on the seismic profile for seismic calibration. For example... Figure 5 In the diagram, the area between the horizontal solid line corresponding to TZ and the horizontal solid line corresponding to TNh represents the Nanhua system.

[0051] Because no wells have been drilled in the ultra-deep ancient strata of the Nanhua System, it is difficult to find comparable stratigraphic interpretations. The strata closest to the Nanhua System are the Sinian System. Test Example 1 of this invention uses drilling parameters and well logs from well-drilled areas within the Sinian System (i.e., seismic calibration and stratigraphic interpretation according to existing methods). The process of Test Example 1 is as follows: Data from well YL1 in a certain area is used, and its logging curves and the distribution of lithological profiles obtained from the logging curves are shown below. Figure 6 As shown on the left, by Figure 6 The stratigraphic interpretation results obtained from the lithological profile shown on the left using seismic analysis software are as follows: Figure 6 As shown on the right.

[0052] To better interpret the information from this stratigraphic interpretation, Figure 6 The stratigraphic interpretation results on the right are placed in the overall stratigraphic interpretation results map of the area where well YL1 is located, as shown below. Figure 7 As shown (where the position marked YL1 is...) Figure 6 The corresponding location, its position and orientation within the Tarim Basin are as follows: Figure 7 (As shown by the dots and lines in the lower right corner). Among them, TJ represents the bottom boundary of the Jurassic system, TO represents the bottom boundary of the Ordovician system, TH3 represents the bottom boundary of the Upper Cambrian system, TH2 represents the bottom boundary of the Middle Cambrian system, TH represents the bottom boundary of the Lower Cambrian system, TZ represents the bottom boundary of the Sinian system, Wb represents the bottom of the drilled well, and TD represents the bottom boundary of the Devonian system.

[0053] Following the procedure in Embodiment 1 of this invention, well-free seismic calibration was performed in the area where well YL1 is located, and the results are as follows: Figure 8 As shown (the location and orientation of the points corresponding to the synthetic record in the Tarim Basin are as follows) Figure 8 The dots and lines in the lower right corner are shown; Figure 8the lower left corner of the seismic data is missing, presenting a missing corner). By splicing the seismic interpretation results of Figure 7 and Figure 8 together, the position and strike of the Tarim Basin and the spliced results of the stratum interpretation are shown in Figure 9 As can be seen from the spliced results, the stratum horizon calibration interpretation results of the Sinian stratum of the area where the well YL1 is located by the test example 1 and the example 1 are consistent in the stratum structure interpretation scheme, the Sinian east-west stratum thickness has changes, and it is indicated that the present application is accurate and feasible for the seismic calibration and stratum interpretation.

[0054] The above describes the embodiments of the present application. However, the present application is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of well-free seismic calibration, characterized in that, The method comprises the following steps: (1) determining the lithology of outcrop strata in a study area; (2) obtaining lithology parameters of the outcrop strata in the study area; (3) making a virtual well synthetic record based on the lithology parameters; (4) obtaining a seismic interpretation scheme of the study area by seismic forward modeling based on the virtual well synthetic record; wherein the seismic forward modeling comprises two-dimensional forward modeling. The lithology parameters comprise rock density and acoustic time difference, and the wave impedance value is calculated according to the formula: wave impedance value = rock density / acoustic time difference, and the virtual well synthetic record is made by using the wave impedance value; In step (2), the way of obtaining the lithology parameters of the outcrop strata in the study area comprises: a lithology-lithology parameter corresponding standard is established to represent the lithology parameters corresponding to different lithologies, and the lithology parameters of the outcrop strata in the study area are determined according to the lithology of the outcrop strata in the study area determined in step (1) and the lithology-lithology parameter corresponding standard; wherein the lithology-lithology parameter corresponding standard is established by calculating the average value of a large number of rock density historical data of mudstone to obtain the rock density corresponding to the mudstone, and by calculating the average value of a large number of acoustic time difference historical data of mudstone to obtain the acoustic time difference corresponding to the mudstone; the lithology-lithology parameter corresponding standard comprises a lithology-rock density corresponding standard, a lithology-acoustic time difference corresponding standard and a lithology-wave impedance value corresponding standard; Alternatively, the lithology parameters of the outcrop strata in the study area come from measured lithology parameters of drilled wells, and the measured lithology parameters of the drilled wells comprise measured lithology parameters of a drilled well section in the study area and / or measured lithology parameters of drilled wells in a neighboring area of the study area.

2. The well-less seismic calibration method of claim 1, wherein, The lithology comprises at least one of mudstone, salt rock, quartzite, gneiss, limestone, granite, gypsum rock, pyroxene rock or dolomite.

3. The well-less seismic calibration method of claim 1, wherein, The depth of the drilled well section in the study area and / or the drilled wells in the neighboring area of the study area is not greater than 6000 meters.

4. The well-less seismic calibration method of claim 1, wherein, The measured lithology parameters of the drilled wells are selected from logging values of drilled wells within a range of 100 km in radius centered on the study area.

5. The well-less seismic calibration method of claim 1, wherein, The virtual well synthetic record is made by using Landmark analysis software.

6. A method for calibrating well-free seismic in ultra-deep ancient strata in a basin, characterized in that, The method comprises the following steps: (1') determining the lithology of outcrop strata in a basin margin of a study area; (2') obtaining lithology parameters of the outcrop strata in the basin margin of the study area, wherein the lithology parameters of the outcrop strata in the basin margin of the study area come from measured lithology parameters of drilled wells, and the measured lithology parameters of the drilled wells are selected from logging values of drilled wells within a range of 100 km in radius centered on the study area; the lithology parameters comprise rock density and acoustic time difference, and the wave impedance value is calculated according to the formula: wave impedance value = rock density / acoustic time difference, and a virtual well synthetic record is made by using the wave impedance value; (3') making a virtual well synthetic record based on the lithology parameters; (4') obtaining a seismic interpretation scheme of super-deep ancient strata in the study area by seismic forward modeling based on the virtual well synthetic record; wherein the seismic forward modeling comprises two-dimensional forward modeling.

7. The well-less seismic calibration method of claim 6, wherein, The super-deep ancient strata in the basin comprise Nanhua-Sinian strata, and / or the super-deep ancient strata in the basin partially continue to Archean-Middle Proterozoic metamorphic rock basement structure.

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