Method for identifying volcanic rock weathering crust and inner curtain period based on earthquake multiple attributes

Abstract

The invention belongs to the technical field of oil exploration and development, and discloses a method for identifying volcanic rock weathering crust and interior periods based on multiple seismic attributes, which comprises the following steps: determining a logging chart division boundary; a seismic data volume corresponding to the logging data is read, a cross plot is drawn, and a seismic data volume correction formula is obtained through linear fitting; correcting the seismic data volume of the research area; dividing the corrected data volume through a logging plate division boundary to obtain a first probability volume P1; determining an impedance plate division boundary; performing inversion to obtain an inversion resistance body; dividing the inversion impedance body according to an impedance plate division boundary to obtain a second probability body P2; performing weighted calculation on the P1 and the P2 to obtain a volcanic rock interior period identification parameter body P3; and establishing a recognition plate by using the P3, and determining a division boundary of the recognition plate to obtain a volcanic rock interior period recognition probability body P4. According to the method, well-seismic data unification is realized, and the weathering crust and the inner curtain period can be effectively identified in combination with an impedance inversion data body prediction result.

Description

Technical Field

[0001] This invention belongs to the field of petroleum exploration and development technology, specifically relating to a method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification. Background Technology

[0002] Volcanic rock masses generally exhibit two stratigraphic structures: a weathering crust and internal phases. The weathering crust is a layered geological body formed by physical and chemical weathering, such as leaching, in a surface environment. It is mainly located at the top of the volcanic rock mass and is characterized by well-developed fractures and good reservoir properties. Internal phases are located further from the top of the rock mass, with weaker weathering and leaching, resulting in relatively poorer reservoir properties. Internal phases are layered, obliquely draped over the crater, and form an unconformable contact with the overlying weathering crust. Conventional methods for identifying the weathering crust and internal phases of volcanic rocks mainly rely on seismic profile reflection characteristics for tracking and characterization, which are greatly influenced by subjective factors and have multiple interpretations.

[0003] In the prior art, Chinese patent CN116125555A discloses a method and apparatus for determining the effective reservoir distribution of granite weathering crust. The method includes: analyzing seismic facies types and distribution characteristics based on three-dimensional seismic data of the target granite weathering crust reservoir; extracting reservoir attribute characteristics of the target granite weathering crust reservoir along the layers using maximum amplitude attributes to obtain seismic sensitivity attribute distribution characteristics; dividing the vertical structure of the target granite weathering crust reservoir using well logging data; calibrating the vertical structure with the seismic facies types of the target granite weathering crust reservoir to establish a correspondence between seismic facies types and vertical structures; and determining the effective reservoir distribution characteristics of the target granite weathering crust reservoir based on the seismic facies distribution characteristics, seismic sensitivity attribute distribution characteristics, and the correspondence between seismic facies types and vertical structures. While this patent's technical solution can accurately determine the effective reservoir distribution characteristics of the target granite weathering crust reservoir, it does not disclose methods for identifying and judging internal phase structures.

[0004] Chinese patent CN104007468A discloses a method for characterizing the spatial distribution of volcanic rocks based on amplitude-variance volume seismic attributes. This method extracts volcanic overflow facies data from high-amplitude 3D seismic data and simultaneously extracts volcanic conduit facies data from the variance volume data, fusing the two to achieve a combined characterization of the overflow and conduit facies. This patent's method integrates variance and amplitude data volumes for predictive research on Carboniferous volcanic reservoirs. However, this patent does not address the lithological identification and judgment of the weathering crust and internal stratigraphic phases of Carboniferous volcanic rocks. Summary of the Invention

[0005] This invention aims to address the technical problems existing in the background art by providing a method for identifying the weathering crust and internal stages of volcanic rocks based on seismic multi-attribute identification. It comprehensively considers the reflection of stratigraphic occurrence by dip angle and azimuth angle, and the reflection of lithology and physical properties by impedance volume. It uses multiple attributes to comprehensively identify the weathering crust and internal stages of volcanic rocks, thereby solving the problem of Carboniferous stratigraphic division. It does not rely on subjective human factors and objectively analyzes the distribution characteristics of the internal stratigraphic system of the Carboniferous system to reflect the true occurrence and distribution of the internal stratigraphic system, thus better guiding the deployment of evaluation wells and oil testing of old wells.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] A method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute analysis, the method comprising the following steps:

[0008] Step S1: Using the well logging dip angle results of all wells in the study area, statistically analyze the well logging dip angle and well logging azimuth angle of the volcanic weathering crust and internal stages, establish identification charts for the well logging dip angle and well logging azimuth angle of the volcanic weathering crust and internal stages, and determine the boundary between the weathering crust and the internal stages of the well logging charts.

[0009] Step S2: Extract the well logging dip and well logging azimuth of all wells in the study area. Using seismic data, read the seismic dip and seismic azimuth data corresponding to each well logging dip and well logging azimuth data, and draw a dip and azimuth intersection diagram. The horizontal axis represents the seismic dip and seismic azimuth, and the vertical axis represents the well logging dip and well logging azimuth. Perform linear fitting to obtain the seismic data volume correction formula.

[0010] Step S3: Using the seismic data volume correction formula obtained in step S2, correct the seismic dip angle and seismic azimuth angle data volumes extracted from the seismic data volumes in the study area to obtain the corrected seismic data volumes.

[0011] Step S4: Using the well logging chart boundary defined in Step S1, the corrected seismic data volume in Step S3 is divided to obtain the first probability volume P1. P1 is a dimensionless quantity with a value of 0 or 1. P1 = 0 represents the weathering crust, and P1 = 1 represents the internal phase.

[0012] Step S5: Statistically analyze the impedance data of all single wells in the study area, establish impedance charts for the weathering crust and internal phases of volcanic rocks, and determine the boundary between the impedance charts for the weathering crust and internal phases.

[0013] Step S6: Based on the single-well impedance data, perform impedance inversion using seismic data to obtain the inverted impedance volume;

[0014] Step S7: Based on the boundary division of the impedance diagram in Step S5, divide the inversion impedance volume in Step S6 to obtain the second probability volume P2. P2 is a dimensionless quantity with a value of 0-1. P2=0 represents the weathering crust, and P2=1 represents the internal period.

[0015] Step S8: Using the first probability volume P1 in step S4 and the second probability volume P2 in step S7, the volcanic rock internal phase identification parameter volume P3 is obtained by weighted calculation. P3 is a dimensionless quantity with a value of 0-1. P3=0 represents the weathering crust, and P3=1 represents the internal phase.

[0016] Step S9: Using the volcanic rock internal phase identification parameter volume P3, establish an identification chart of volcanic rock weathering crust and internal phase, determine the boundary between the identification chart of weathering crust and internal phase, and obtain the volcanic rock internal phase identification probability volume P4. P4 is a dimensionless quantity, and the value of P4 is 0 or 1. P4 = 0 represents weathering crust, and P4 = 1 represents internal phase.

[0017] Furthermore, in step S1, establishing a well logging formation dip and azimuth identification chart for the weathering crust and internal stages of volcanic rocks specifically includes:

[0018] First, classify the formation dip and azimuth of all well logs into two categories: volcanic rock weathering crust and internal phases. Then, create a scatter plot in Excel to obtain the identification charts of well log formation dip and azimuth for volcanic rock weathering crust and internal phases.

[0019] Furthermore, in step S1, determining the boundary between the weathering crust of the volcanic rock and the logging charts of the internal stages specifically includes:

[0020] Based on the distribution of data points of volcanic rock weathering crust and internal phases in the map, the boundary between volcanic rock weathering crust and internal phases is determined.

[0021] Furthermore, in step S2, a scatter plot is created in Excel to draw the intersection diagram of tilt angle and azimuth angle.

[0022] Furthermore, the seismic data volume correction formula in step S2 is as follows:

[0023] Aw = a1 × As + b1

[0024] Dw=a2×Ds+b2

[0025] In the above formula:

[0026] Aw is the corrected azimuth angle, in degrees;

[0027] As is the earthquake azimuth angle, in degrees;

[0028] a1 is the azimuth correction coefficient, which is dimensionless;

[0029] b1 is the azimuth correction constant, which is dimensionless.

[0030] Dw is the corrected tilt angle, in degrees;

[0031] Ds is the seismic dip angle in °, and a2 is the dip angle correction coefficient, which is dimensionless.

[0032] b2 is the tilt correction constant, which is dimensionless.

[0033] Furthermore, in step S5, a scatter plot is created in Excel using the single-well impedance data, which is the impedance chart.

[0034] Furthermore, in step S5, the boundary line between the impedance data of the volcanic rock weathering crust and the internal phases, determined according to the distribution pattern, is the boundary line for the impedance chart.

[0035] Furthermore, in step S8, the weighted calculation formula for the volcanic rock internal phase identification parameter volume P3 is as follows:

[0036] P3 = (P1 + P2) / 2

[0037] In the above formula: P3 is the identification parameter for the internal phases of volcanic rocks, a dimensionless quantity with a value of 0-1. P3=0 represents the weathering crust, and P3=1 represents the internal phase.

[0038] P1 is the first probability body, a dimensionless quantity with a value of 0 or 1. P1 = 0 represents the weathered shell, and P1 = 1 represents the insider period.

[0039] P2 is the second probability body, a dimensionless quantity with a value of 0-1. P2=0 represents the weathered crust, and P2=1 represents the insider period.

[0040] Furthermore, in step S9, a scatter plot is created in Excel based on the volcanic rock internal phase identification parameter P3, which is the identification chart of the volcanic rock weathering crust and internal phases.

[0041] Furthermore, in step S9, the boundary between the weathering crust and the internal phase is determined based on the scatter plot data distribution pattern of the weathering crust and the internal phase.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] (1) The method of the present invention uses well logging data to correct the seismic dip angle and seismic azimuth angle data, realizes the unification of well seismic data, and combines it with the prediction results of inversion impedance volume. It can effectively identify the two types of stratigraphic structures, weathering crust and internal stage, objectively analyze the distribution characteristics of the internal stratigraphic system of Carboniferous, reflect the true occurrence distribution of the internal stratigraphic system of Carboniferous, guide oil and gas exploration, and has a more sufficient and reliable theoretical basis.

[0044] (2) The method of this invention comprehensively considers the reflection of dip angle and azimuth angle on the stratigraphic attitude, and the reflection of impedance body on lithology and physical properties. It uses multiple attributes to comprehensively identify the weathering crust and internal phases. Compared with the traditional seismic co-axial tracking method, it is more operable, does not rely on subjective human factors, and objectively divides the internal strata of volcanic rock bodies, guiding the later evaluation well location deployment and old well oil testing. The theoretical basis is more sufficient and the reliability is higher. Moreover, the identification results are verified by combining the wellbore curves in the later stage, which confirms that the identification results of the Carboniferous stratigraphic structure of this method are reliable.

[0045] (3) By applying the method of this invention, the problem of insufficient objectivity in the division of Carboniferous strata by relying on subjective human factors is solved. The method of this invention relies on the integration of various attributes to objectively analyze the internal strata division of the Carboniferous system, guiding the deployment of evaluation well locations and oil testing of old wells in later stages. In a certain oilfield, well 527 was tested in two stages, namely the top weathering crust and the inner layer, for a total of three layers. Oil testing was conducted in the C5 layer of the Carboniferous weathering crust, yielding a depth of 107.9m. 3 High-yield oil flow was observed, with a depth of 20.6 m obtained during the second test of layer C4 in the internal phase. 3 High-yield oil flow was observed, with a depth of 55.44 m obtained during the C3 layer test in the internal phase. 3 High-yield oil flow; and following the breakthrough in oil testing in well 527 of the oilfield, the next step is to learn from the reservoir formation model in well 9591 of the same oilfield and continue to promote the overall application of this method, which is expected to further expand the exploration results in the Carboniferous system of the area. Attached Figure Description

[0046] Figure 1 This is a flowchart of a method for identifying the weathering crust and internal phases of volcanic rocks based on multiple earthquake attributes, according to an embodiment of the present invention.

[0047] Figure 2 This is a schematic diagram showing the boundary between the weathering crust of volcanic rocks and the internal phases in a well logging chart according to an embodiment of the present invention.

[0048] Figure 3 This is a schematic diagram showing the boundary between the weathering crust of volcanic rocks and the internal phases in an embodiment of the present invention.

[0049] Figure 4 This is a schematic diagram illustrating the boundary between the weathering crust of volcanic rocks and the internal phases in an embodiment of the present invention.

[0050] Figure 5 This is a schematic diagram of a conventional seismic profile according to an embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of the seismic profile identification result of the probability volume P4 for identifying the internal phases of volcanic rocks, which is the final calculation in this embodiment of the invention. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Example 1

[0054] This invention provides a method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute analysis, combined with... Figure 1 As shown, the method includes the following steps:

[0055] Step S1: Using the well logging dip angle results of all wells in the study area, statistically analyze the well logging dip angle and well logging azimuth angle of the volcanic weathering crust and internal stages, establish identification charts for the well logging dip angle and well logging azimuth angle of the volcanic weathering crust and internal stages, and determine the boundary between the weathering crust and the internal stages of the well logging charts.

[0056] When determining the boundary between well logging charts for volcanic weathering crust and internal stages, first, based on the two categories of volcanic weathering crust and internal stages, statistical analysis of the formation dip and azimuth of all well logs is performed. A scatter plot is then created in Excel to obtain the identification charts for the well logging formation dip and azimuth of volcanic weathering crust and internal stages. Based on the distribution of data points for volcanic weathering crust and internal stages in the charts, the boundary between the well logging charts for volcanic weathering crust and internal stages is determined. Figure 2 As shown.

[0057] Step S2: Extract the well logging dip and azimuth of all wells in the study area. Using seismic data, read the corresponding seismic dip and azimuth data volumes for each well logging dip and azimuth data. Plot a dip-azimuth intersection plot in Excel, with the horizontal axis representing the seismic dip and azimuth, and the vertical axis representing the well logging dip and azimuth. Perform linear fitting to obtain the following seismic data volume correction formula:

[0058] Aw=a1×As+b1 (1)

[0059] Dw=a2×Ds+b2 (2)

[0060] In equations (1)-(2) above:

[0061] Aw is the corrected azimuth angle, in degrees;

[0062] As is the earthquake azimuth angle, in degrees;

[0063] a1 is the azimuth correction coefficient, which is dimensionless;

[0064] b1 is the azimuth correction constant, which is dimensionless.

[0065] Dw is the corrected tilt angle, in degrees;

[0066] Ds is the seismic dip angle in °, and a2 is the dip angle correction coefficient, which is dimensionless.

[0067] b2 is the tilt correction constant, which is dimensionless.

[0068] Among them, the dip angle and azimuth of the strata are geometric attributes, while impedance is an inversion attribute. Due to the difference in the stratigraphic attitude between the weathering crust of volcanic rocks and the internal stages, there are significant differences in the dip angle and azimuth of the strata; while the differences in impedance caused by differences in lithology and physical properties can be used as a method to identify the weathering crust of volcanic rocks and the internal stages.

[0069] Both well logging data and seismic data can be used to obtain the dip angle and azimuth angle data of the formation.

[0070] Formation dip logging is an existing logging method that can measure the actual formation dip angle and formation azimuth angle. It provides point data from a single well, which is actual measured data. The vertical sampling interval is 0.125m, and the resolution is high.

[0071] Seismic data is a data volume, and the seismic dip angle and seismic azimuth angle can be calculated using existing methods. It is predictive data with a sampling interval of 2ms, corresponding to a depth interval of about 4m, which has low resolution.

[0072] The well logging method obtains actual formation dip and azimuth data, which are the actual point data. Seismic dip and azimuth data obtained from earthquake prediction are predicted volumetric data, which contain errors compared to the measured data. Step S2 corrects the seismic dip and azimuth data using the well logging formation dip and azimuth data, resulting in more accurate formation dip and azimuth volumetric data.

[0073] Step S3: Using the seismic data volume correction formula obtained in step S2, correct the seismic dip angle and seismic azimuth angle data volumes extracted from the seismic data volume in the study area to obtain the corrected seismic dip angle and seismic azimuth angle data volumes, making them closer to the well logging formation dip angle and well logging formation azimuth angle (i.e., the true formation dip angle and azimuth angle data volumes).

[0074] Step S3 uses well logging data to correct the seismic data volume, thus achieving the unification of well-seismic data.

[0075] Step S4: Using the well logging chart boundary defined in Step S1, the corrected seismic data volume in Step S3 is divided to obtain the first probability volume P1. P1 is a dimensionless quantity, and the value of P1 is 0 or 1. Among them, P1 = 0 represents the weathering crust, and P1 = 1 represents the internal period.

[0076] according to Figure 2 The dividing line is as follows: when the well logging dip angle is <40° and the well logging azimuth angle is <80°, it is a weathering crust, and the corresponding P1 = 0; otherwise, it is an internal phase, and the corresponding P1 = 1. Correspondingly, when the seismic dip angle is <40° and the seismic azimuth angle is <80°, it is a weathering crust, and the corresponding P1 = 0; otherwise, it is an internal phase, and the corresponding P1 = 1.

[0077] Step S5: Statistically analyze the impedance data of all single wells in the study area, establish impedance charts for the weathering crust and internal phases of volcanic rocks, and determine the boundary between the impedance charts for the weathering crust and internal phases.

[0078] like Figure 3 As shown, a scatter plot is created in Excel using single-well impedance data, which serves as the impedance chart. The boundary line between the impedance data of the volcanic weathering crust and the internal stages, determined based on the distribution pattern, is the dividing line of the impedance chart: impedance <11000g / cm 3 ×m / s represents the weathering crust; impedance >11700g / cm 3 ×m / s represents the internal phase; impedance is at 11000g / cm. 3 ×m / s-11700g / cm 3 The area between ×m / s is a transition zone, which may be an internal phase or a weathering crust;

[0079] Step S6: Based on the single-well impedance data, perform impedance inversion using seismic data to obtain the inverted impedance volume;

[0080] Step S7: Based on the impedance diagram division boundary in Step S5, divide the inversion impedance volume in Step S6 to obtain the second probability volume P2. P2 is a dimensionless quantity with a value of 0-1. Among them, P2=0 represents the weathering crust and P2=1 represents the internal period.

[0081] according to Figure 3 The impedance chart delimitation is set if the inverted impedance volume value is less than 11000 g / cm. 3 If the value is × m / s, then it is a weathering crust, and the corresponding P2 = 0; if the inversion impedance value is greater than 117000 g / cm³, then it is a weathering crust. 3×m / s, then it is the internal phase, corresponding to P2=1; if the inversion impedance value is at 11000g / cm 3 ×m / s-11700g / cm 3 The area between ×m / s is a transition zone, which may be an internal phase or a weathering crust, with the corresponding P2 = (inversion impedance volume - 11000) / (11700 - 11000);

[0082] Since the impedance chart has a transition zone, when calculating P2 using probability, the closer the inverted impedance volume value is to 11700, the greater the corresponding probability P2, and the closer it is to 1, the greater the possibility of it being an insider period. The specific values ​​of the impedance boundary in different blocks may vary.

[0083] Step S8: Using the first probability volume P1 from step S4 and the second probability volume P2 from step S7, the volcanic rock internal phase identification parameter volume P3 is calculated by weighting. The weighting calculation formula is as follows:

[0084] P3=(P1+P2) / 2 (3)

[0085] In the above formula (3): P3 is the identification parameter for the internal stage of volcanic rock, which is dimensionless and has a value of 0-1. P3=0 represents the weathering crust, and P3=1 represents the internal stage.

[0086] P1 is the first probability body, a dimensionless quantity with a value of 0 or 1. P1 = 0 represents the weathered shell, and P1 = 1 represents the insider period.

[0087] P2 is the second probability body, a dimensionless quantity with a value of 0-1. P2=0 represents the weathered crust, and P2=1 represents the insider period.

[0088] Step S9: Using the volcanic rock internal phase identification parameter volume P3, establish an identification chart of volcanic rock weathering crust and internal phase, determine the boundary between the identification chart of weathering crust and internal phase, and obtain the volcanic rock internal phase identification probability volume P4. P4 is a dimensionless quantity, and the value of P4 is 0 or 1, where: P4 = 0 is weathering crust, and P4 = 1 is internal phase.

[0089] like Figure 4 As shown, based on the volcanic rock internal phase identification parameters P3, a scatter plot is created in Excel, which serves as the identification chart for the volcanic rock weathering crust and internal phases. Based on the distribution pattern of the scatter plot data for the weathering crust and internal phases, the boundary between the weathering crust and internal phases is determined, corresponding to... Figure 4 In this context, P3 = 0.5, meaning that if P3 > 0.5, it indicates an insider trading period, with a corresponding P4 = 1; otherwise, it indicates a weathered crust, with a corresponding P4 = 0. It should be noted that the value of the boundary P3 is determined based on the actual map boundary, and the boundary may differ for different blocks.

[0090] In step S9, the prediction results of earthquake dip angle, earthquake azimuth angle and impedance are comprehensively considered. The factors considered are more comprehensive. The probability volume P4 of the volcanic rock internal phase identification obtained by multi-attribute fusion calculation is more accurate and the identification results are more in line with reality.

[0091] This invention achieves a unified approach to wellbore dip and azimuth, comprehensively considering the reflection of dip and azimuth on formation attitude, and the reflection of impedance volume on lithology and physical properties. It utilizes multiple attributes to comprehensively identify the weathering crust and internal phases, offering greater operability than traditional seismic axis tracing methods. It does not rely on subjective human factors, objectively dividing the internal strata of volcanic rock masses, guiding subsequent well placement and well testing. The theoretical basis is more comprehensive and the reliability is higher. Furthermore, subsequent verification of the identification results using wellbore curves confirms the reliability of this method in identifying Carboniferous strata structures.

[0092] Example 2

[0093] This invention provides a detailed description using the Carboniferous reservoir in well 9591 of a certain oilfield as an example. In the early stages, it was difficult to distinguish the internal strata of the Carboniferous system in this reservoir using well logging and seismic data. Stratigraphic delineation was heavily influenced by human intervention and could not objectively reflect the stratigraphic structure characteristics of the area, leading to delays in subsequent rolling exploration and evaluation studies.

[0094] like Figure 5 The diagram shows a conventional seismic profile of the Carboniferous reservoir in this well area. The weathering crust and the inner strata exhibit different attitudes. The weathering crust is parallel to the top surface of the Carboniferous system, while the inner strata are arranged in an oblique pattern. They are usually identified manually, but the boundaries are unclear and the interpretation is complex.

[0095] This invention applies the method from Example 1 to the Carboniferous reservoir in this well area to identify two types of stratigraphic structures: weathering crust and internal stages, guiding oil exploration and production. Specifically, it includes the following steps:

[0096] Step S1: Using the well logging dip angle results of all wells in the study area, statistically analyze the dip angle and azimuth of the volcanic weathering crust and internal stages, establish well logging dip angle and azimuth identification charts for the volcanic weathering crust and internal stages, and determine the boundary between the well logging charts of the volcanic weathering crust and internal stages.

[0097] Among them, the weathering crust corresponds to a well logging formation dip angle <15° and a well logging formation azimuth angle <120°, while the internal phase corresponds to a well logging formation dip angle >15° and a well logging formation azimuth angle >120°.

[0098] Step S2: Extract the well logging dip and azimuth of all wells in the study area. Using seismic data, read the corresponding seismic dip and azimuth data volumes for each well logging dip and azimuth data. Plot a dip-azimuth intersection plot in Excel, with the horizontal axis representing the seismic dip and azimuth, and the vertical axis representing the well logging dip and azimuth. Perform linear fitting to obtain the following seismic data volume correction formula:

[0099] Aw = 1.1 * As - 18 (4)

[0100] Dw=2.6*Ds-3.8 (5)

[0101] Step S3: Using the correction formulas (4)-(5), the seismic dip angle and seismic azimuth angle data volumes extracted from the seismic data volume in the study area are corrected to obtain the corrected seismic data volume, which is closer to the well logging formation dip angle and well logging formation azimuth angle (that is, the real formation dip angle and azimuth angle data volume).

[0102] Step S4: Using the well logging chart boundary defined in Step S1, the corrected seismic data volume in Step S3 is divided to obtain the first probability volume P1. P1 is a dimensionless quantity, and the value of P1 is 0 or 1. Among them, P1 = 0 represents the weathering crust, and P1 = 1 represents the internal period.

[0103] Step S5: Statistically analyze the impedance data of all single wells in the study area, establish impedance charts for the weathering crust and internal phases of volcanic rocks, and determine the boundary between the impedance charts for the weathering crust and internal phases.

[0104] Among them, the weathering crust of the Carboniferous system has a low impedance, less than 11500 g / cm. 3 ×m / s; the impedance of the internal phase is relatively high, greater than 11500 g / cm. 3 ×m / s, that is, the impedance value corresponding to the boundary of the impedance chart is 11500 g / cm. 3 ×m / s;

[0105] Step S6: Based on the single-well impedance data, perform impedance inversion using seismic data to obtain the inverted impedance volume;

[0106] Step S7: Based on the impedance diagram division boundary in Step S5, divide the inversion impedance volume in Step S6 to obtain the second probability volume P2. P2 is a dimensionless quantity with a value of 0-1. Among them, P2=0 represents the weathering crust and P2=1 represents the internal period.

[0107] Step S8: Using the first probability body P1 in step S4 and the second probability body P2 in step S7, calculate the volcanic rock internal phase identification parameter body P3 according to formula (3). P3 is a dimensionless quantity with a value between 0 and 1. P3 = 0 represents the weathering crust, and P3 = 1 represents the internal phase.

[0108] Step S9: Using the volcanic rock internal phase identification parameter volume P3, establish an identification chart of volcanic rock weathering crust and internal phase, determine the boundary of the identification chart of volcanic rock weathering crust and internal phase, and obtain the volcanic rock internal phase identification probability volume P4. P4 is a dimensionless quantity, and the value of P4 is 0 or 1, where: P4 = 0 is weathering crust, and P4 = 1 is internal phase.

[0109] like Figure 6 The image shown is the seismic profile identification result of the final calculated probability volume P4 for identifying internal volcanic rock phases. The weathering crust shows significant differences in properties (dip, azimuth, impedance) compared to the internal phases. Figure 5 Compared to conventional seismic profiles, Figure 6 The Carboniferous strata in the middle have better continuity and clearer interface features; there is a clear angular unconformity between the strata at the top of the Carboniferous and the strata inside the Carboniferous. After fusion, the relatively continuous Carboniferous strata on the seismic profile are favorable areas for later dominant reservoirs.

[0110] In this embodiment of the invention, the weathering crust and the inner stage are clearly different in properties and can be well distinguished. Moreover, they are consistent with the reflection characteristics of single wells and seismic profiles, which verifies the effectiveness of the method in this embodiment of the invention.

[0111] The application of this invention solves the problem that relying on subjective human factors is insufficient for objective classification of Carboniferous strata. This invention's method relies on the objective analysis of various attributes to classify the internal strata of the Carboniferous system, guiding subsequent well placement and well testing. In this case, well 527 in the oilfield was tested in two phases—the upper weathering crust and the inner strata—resulting in a total of three layers. Specifically, a 107.9m well was tested in the C5 layer of the Carboniferous weathering crust. 3 High-yield oil flow was observed, with a depth of 20.6 m obtained during the second test of layer C4 in the internal phase. 3 High-yield oil flow was observed, with a depth of 55.44 m obtained during the C3 layer test in the internal phase. 3 High-yield oil flow.

[0112] Following the breakthrough in oil testing at well 527 in the oilfield, the next step is to learn from the reservoir formation model at well 9591 in the same oilfield and continue to promote the overall application of this method, which is expected to further expand the exploration results in the Carboniferous system of the area.

[0113] The above description is merely an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification, characterized in that, The method includes the following steps: Step S1: Using the well logging dip angle results of all wells in the study area, statistically analyze the well logging dip angle and well logging azimuth angle of the weathered crust and internal stages of volcanic rocks, establish identification charts for the well logging dip angle and well logging azimuth angle of the weathered crust and internal stages, and determine the boundary between the weathered crust and the well logging charts of internal stages. Step S2: Extract the well logging dip and well logging azimuth of all wells in the study area. Using seismic data, read the seismic dip and seismic azimuth data corresponding to each well logging dip and well logging azimuth data, and draw a dip and azimuth intersection diagram. The horizontal axis represents the seismic dip and seismic azimuth, and the vertical axis represents the well logging dip and well logging azimuth. Perform linear fitting to obtain the seismic data volume correction formula. Step S3: Using the seismic data volume correction formula obtained in step S2, correct the seismic dip angle and seismic azimuth angle data volumes extracted from the seismic data volumes in the study area to obtain the corrected seismic data volumes. Step S4: Using the well logging chart boundary defined in Step S1, the corrected seismic data volume in Step S3 is divided to obtain the first probability volume P1. P1 is a dimensionless quantity with a value of 0 or 1. P1 = 0 represents the weathering crust, and P1 = 1 represents the internal phase. Step S5: Statistically analyze the impedance data of all single wells in the study area, establish impedance charts for the weathering crust and internal phases of volcanic rocks, and determine the boundary between the impedance charts for the weathering crust and internal phases. Step S6: Based on the single-well impedance data, perform impedance inversion using seismic data to obtain the inverted impedance volume; Step S7: Based on the boundary division of the impedance diagram in Step S5, divide the inversion impedance volume in Step S6 to obtain the second probability volume P2. P2 is a dimensionless quantity with a value of 0-1. P2=0 represents the weathering crust, and P2=1 represents the internal period. Step S8: Using the first probability volume P1 in step S4 and the second probability volume P2 in step S7, the volcanic rock internal phase identification parameter volume P3 is obtained by weighted calculation. P3 is a dimensionless quantity with a value of 0-1. P3=0 represents the weathering crust, and P3=1 represents the internal phase. Step S9: Using the volcanic rock internal phase identification parameter volume P3, establish an identification chart of volcanic rock weathering crust and internal phase, determine the dividing line between the weathering crust and internal phase identification chart, and obtain the volcanic rock internal phase identification probability volume P4. P4 is a dimensionless quantity, and the value of P4 is 0 or 1. P4 = 0 represents weathering crust, and P4 = 1 represents internal phase.

2. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 1, characterized in that, In step S1, establishing a well logging formation dip and azimuth identification chart for the weathering crust and internal stages of volcanic rocks specifically includes: First, classify the formation dip and azimuth of all well logs into two categories: volcanic rock weathering crust and internal phases. Then, create a scatter plot in Excel to obtain the identification charts of well log formation dip and azimuth for volcanic rock weathering crust and internal phases.

3. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 2, characterized in that, In step S1, determining the boundary between the weathering crust of the volcanic rock and the logging charts of the internal stages specifically includes: Based on the distribution of data points of volcanic rock weathering crust and internal phases in the map, the boundary between volcanic rock weathering crust and internal phases is determined.

4. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 1, characterized in that, In step S2, a scatter plot is created in Excel to draw the intersection diagram of tilt angle and azimuth angle.

5. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 1 or 4, characterized in that, The seismic data volume correction formula in step S2 is: Aw = a1 × As + b1 Dw=a2×Ds+b2 In the above formula: Aw is the corrected azimuth angle, in degrees; As is the earthquake azimuth angle, in degrees; a1 is the azimuth correction coefficient, which is dimensionless; b1 is the azimuth correction constant, which is dimensionless. Dw is the corrected tilt angle, in degrees; Ds is the seismic dip angle in °, and a2 is the dip angle correction coefficient, which is dimensionless. b2 is the tilt correction constant, which is dimensionless.

6. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 1, characterized in that, In step S5, a scatter plot is created in Excel using the single-well impedance data, which is the impedance chart.

7. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 6, characterized in that, In step S5, the boundary line between the impedance data of the weathering crust and the internal phases of volcanic rocks, determined according to the distribution pattern, is the boundary line for the impedance chart.

8. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 1, characterized in that, In step S8, the weighted calculation formula for the volcanic rock internal phase identification parameter body P3 is as follows: P3 = (P1 + P2) / 2 In the above formula: P3 is the identification parameter for the internal phases of volcanic rocks, a dimensionless quantity with a value of 0-1. P3=0 represents the weathering crust, and P3=1 represents the internal phase. P1 is the first probability body, a dimensionless quantity with a value of 0 or 1. P1 = 0 represents the weathered shell, and P1 = 1 represents the insider period. P2 is the second probability body, a dimensionless quantity with a value of 0-1. P2=0 represents the weathered crust, and P2=1 represents the insider period.

9. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 1, characterized in that, In step S9, a scatter plot is created in Excel based on the volcanic rock internal phase identification parameter P3, which is the identification chart of the volcanic rock weathering crust and internal phases.

10. The method for identifying the weathering crust and internal phases of volcanic rocks based on seismic multi-attribute identification according to claim 9, characterized in that, In step S9, the boundary between the weathering crust and the internal period is determined based on the scatter plot data distribution pattern of the weathering crust and the internal period.

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