CN113514891B - A method for determining the extent of oil-water transition zone based on seismic inversion - Google Patents

Abstract

An oil-water transition zone range determining method based on seismic inversion. The method is mainly used for solving the problem of oil-water transition zone range construction, namely oil bottom and water top position calibration, and comprises the following six steps: preparing a basic elastic parameter curve required by inversion, preparing a seismic data body required by inversion, preparing a chart required by elastic parameter inversion result geological interpretation, performing prestack simultaneous geostatistical inversion, performing lithology interpretation, performing configuration co-simulation, establishing a water saturation body, and determining an oil-water transition zone range through the water saturation body. The invention constructs an oil saturation inversion method based on pre-stack seismic data, carries out water saturation prediction through quantitative relations between sensitive elastic parameters and lithology and water saturation established by a well region, is suitable for calibration of a well-free region oil-water transition zone range represented by an external expansion region, and realizes effective calibration of the well-free region oil-water transition zone range.

Description

A method for determining the extent of oil-water transition zone based on seismic inversion

technical field

The invention relates to a method for determining the oil-water transition zone range of a structural oil reservoir, which is applied in the field of oilfield edge expansion and development.

Background technique

Structural reservoir oil-water transition zone range—that is, the problem of calibration of the position of oil bottom and water top. This position is the largest reserve range of the oilfield and has important value for the expansion and development of the oilfield. In the past, various methods relying on well data were used to solve the calibration problem, which can be summarized into the following five types: one is the capillary pressure curve method. Three-dimensional attributes determine the position of the oil-water transition zone; the second is the core analysis method, through dripping water, microscope observation, and various geochemical analysis methods to determine the distribution of oil and water in the core at different positions, and determine the position of the transition zone; the third is the logging interpretation method, using qualitative or Quantitative method, analyzing the difference in the curve characteristics of water-bearing and oil-bearing cores, to determine the position of the oil-water transition zone; the fourth is the production method, mainly through oil testing and sampling methods, to obtain the output, and divide the position of the oil-water transition zone; the fifth is the pressure measurement method , using the well point pressure measurement method to calculate the position of the oil-water transition zone according to the relationship between the oil-water density difference. These are not applicable to the area without wells at the edge of the oilfield. This kind of method can only obtain data by drilling a small number of external expansion evaluation wells to realize the oil-water transition. For the calibration of the belt range, the success rate of external expansion evaluation wells that obviously lack geological basis is low. In the existing literature, different scholars put more emphasis on the application of well data, especially the application of coring well data, in the technical process of calibrating the oil-water transition zone. Not applicable.

SUMMARY OF THE INVENTION

In order to solve the technical problems mentioned in the background art, the present invention constructs an oil saturation inversion method based on pre-stack seismic data, and uses the abundant elastic parameters of pre-stack seismic data to find out which can reflect lithology, water saturation, etc. Through the quantitative relationship between the sensitive elastic parameters and lithology and water saturation established in the well area, the water saturation prediction is carried out, which is suitable for the calibration of the oil-water transition zone in the non-well area represented by the outer expansion area. Effective calibration of the oil-water transition zone in the well area.

The technical scheme of the present invention is: the method for determining the range of the oil-water transition zone based on seismic inversion comprises the following steps:

The first step is to prepare the basic elastic parameter curve required for inversion; the basic elastic parameter curve includes shear wave curve, density curve and longitudinal wave impedance;

This step is realized by the following path: determine whether the seismic data collected in the block contains shear wave curve information, if it does, use it directly; if not, collect multi-level array acoustic logging data of the target layer of 1 to 2 wells in the developed area , to obtain the measured shear wave curve; using the measured shear wave curve, through the Greenberg-Castagna empirical formula, establish the shear wave curve based on the longitudinal wave, porosity and permeability geological parameters; in addition to the shear wave curve, the density elastic parameter curve is obtained by logging, and the compression wave impedance is obtained by Obtained by seismic acquisition; the basic elastic parameter curves required for inversion are prepared, and the basic elastic parameter curves required for inversion are summarized, in which the density is obtained through logging measurements, the P-wave impedance is acquired through seismic acquisition, and the shear-wave impedance is an empirical formula estimation curve;

The data used for analysis in this step include: seismic data volume, multi-level array acoustic wave logging data, well point porosity and permeability geological parameters and density logging curve data; wherein, the seismic data volume selects three-dimensional seismic data; multi-level array acoustic wave data The logging data is selected from the measured data of the wells in the block; the well point porosity and permeability geological parameter data is selected from the logging interpretation results of the wells in the block, and the data must be continuous interpretation results, not segmental interpretation results; density logging curve data Select the logging curves of wells in the block;

The second step is to prepare the seismic data volume required for inversion;

This step is achieved through the following paths:

① Starting from the pre-stack seismic CRP gather data, three seismic processes are performed, including denoising, removing multiples, and energy compensation at different offsets;

② Carry out CRP gather forward modeling for the measured shear wave wells;

③ Combined with the horizon calibration results of the target layer, compare the pre-stack seismic CRP gathers after processing and the measured shear-wave well forward CRP gathers, and observe whether the amplitude variation trend, that is, whether the AVO characteristics are the same, if not, repeat the process of ①, if the same, Carry out the process of ④;

④ Analyze the range of the target horizon according to the horizon calibration results, and determine the CRP angle segment plan. The angle segment range is 3-5 segments. It is necessary to remove the seismic information with low signal-to-noise ratio in the far and near channels. The near track, that is, the incident angle <1°, needs to cover the entire target layer;

⑤ The processed CRP gathers are divided into 3-5 angular ranges and superimposed respectively to obtain multiple post-stack seismic data volumes with different incident angle ranges;

The data used for analysis in this step include: pre-stack CRP gather data, target layer horizon calibration results, and well forward modeling CRP gather results; among which, the selection of pre-stack CRP gather data can realize the plane and vertical range of the study area. Full coverage of the results data, the target layer horizon calibration results select the horizon calibration results that include at least the top and bottom ranges of the target layer and the main marker layers, and the well CRP gather results select the CRP gather results of the target interval of the shear wave well measured in the study area. ;

The third step is to prepare the plates required for the geological interpretation of the elastic parameter inversion results;

This step is achieved through the following paths:

① For the measured shear wave wells, the skeleton geological model is established by using the well lithologic geological parameters and the compression and shear wave curves;

② Perform fluid replacement analysis on the skeleton geological model, from water-saturated to oil-saturated, to clarify the curve variation characteristics of basic elastic parameters. The basic elastic parameters include density, longitudinal wave impedance and shear wave impedance; if the variation range of the basic elastic parameter curve is less than 2% , this method is not applicable;

③ For the blocks where the basic elastic parameter curve changes more than 5%, further establish the relationship chart of uphole lithology, water saturation and various elastic parameters, that is, put the uphole elastic parameter value and the logging interpretation conclusion into the same chart, according to the favorable According to the rule that the overlap range between the area and the background area is less than 10%, the optimal elastic parameters or parameter combination to distinguish lithology and saturation are determined; the favorable area refers to the area with high oil content and low water saturation, and the background area refers to other areas;

利用步骤③优选的地震敏感弹性参数，建立其与地下岩性、饱和度对应关系，进行从地震到地质的解释，弹性参数反演成果地质解释所需的图版准备完毕；

Using the earthquake-sensitive elastic parameters optimized in step 3, establish the corresponding relationship with the underground lithology and saturation, and carry out the interpretation from earthquake to geology. The plates required for the geological interpretation of the inversion results of elastic parameters are prepared;

The extracted data sources used in this step include: measured shear wave well curve data, well logging lithology interpretation data, well logging water saturation interpretation data, and well elastic parameter curve; wherein, the measured shear wave well curve data is selected in the block The measured shear wave wells, the logging lithology and water saturation interpretation data are selected from the logging continuous lithology and water saturation interpretation results in the block, and the shear wave impedance, compressional wave impedance and density obtained in the first step are used for the well elastic parameter curve. Elastic parameter curve;

The fourth step is to perform pre-stack simultaneous geostatistical inversion, and perform lithologic interpretation to obtain lithologic bodies;

The specific implementation path of this step is as follows:

①Using the basic elastic parameter curve data obtained in the first step and the seismic data volume data obtained in the second step, carry out the conventional process of pre-stack simultaneous geostatistical inversion, and obtain three basic elastic parameters—compressive wave impedance and shear wave impedance and the post-stack parametric volume of density;

②Use the density parameter volume as the basic data volume from elasticity to geology;

③Using the plate obtained in the third step, carry out the interpretation from elasticity to geology, and use the relationship between density and lithology to directly convert the density body into a three-dimensional lithologic body;

The fifth step is to perform configuration co-simulation to establish a water saturation volume;

The specific implementation path of this step is as follows: On the basis of the three-dimensional lithologic body obtained in the fourth step, the well water saturation interpretation results during the seismic acquisition period are added, and the configuration co-simulation process is carried out to obtain the three-dimensional water saturation body; The interpretation results of well water saturation during the seismic acquisition period were selected as wells within 5 years between the drilling time and the seismic acquisition period, and the water saturation calculated by this method is the reflection of the underground reservoir water saturation during the seismic acquisition period;

The sixth step is to determine the oil-water transition zone range through the obtained water saturation volume. The specific realization path is as follows:

① According to the relative permeability relationship established by the coring data of the target layer in the development area, the water saturation value range of pure oil and pure water produced in the oil layer is defined; Relative permeability relationship data;

②Using the three-dimensional water saturation volume obtained in the fifth step, according to the requirements of the water saturation value range, the bottom of the pure oil, namely the oil bottom, and the water top, which is the bottom of the pure water, are calibrated in the three-dimensional space, between the two It is the oil-water transition zone range, and the calibration of the oil-water transition zone range is completed.

The invention has the following beneficial effects: structural oil reservoirs, as monolithic oil reservoirs, are generally located in the center of the oil field, and are the first choice for development and production. reserves. However, as the structural oil reservoir in the main block, the quality of reserves is much better than that in other blocks, so the research on the expansion potential of structural oil reservoir is of great significance. After the experimental application of the present invention, effective analysis was carried out on the edge expansion potential of Daqing Oilfield, and the edge expansion potential of the Pu group in the Eastern Sartu structure was successfully found, with a submitted reserve of 150,000 tons.

Description of drawings:

Figure 1 shows the workflow of pre-stack inversion residual oil prediction. Pre-stack inversion residual oil prediction workflow

Figure 2 shows the key links of pre-stack inversion saturation prediction, including forward CRP gather and fluid replacement analysis. The left picture is the forward CRP gather, and the right picture is the fluid replacement analysis result.

Figure 3 shows the expansion of the same layer of oil and water in the eastern Portuguese group of Sartu.

Detailed ways:

The present invention will be further described below in conjunction with the specific embodiments applied to the eastern expansion of S oilfield and the accompanying drawings:

The specific implementation process is as follows:

The first step is to prepare the basic elastic parameter curve required for inversion; the basic elastic parameter curve includes shear wave curve, density curve and longitudinal wave impedance;

This step is achieved through the following paths:

① The earthquake in the example block is the 80-fold coverage 3D seismic data collected in 2008 with a 10m×10m panel, and the P-wave information is collected. The P-wave impedance curve can be obtained by extracting the side-channel inversion, but the S-wave information is not collected;

② Acoustic logging data of 6 multi-level sub-arrays were collected in the development area, including shear wave information. Using the shear wave curves of 6 actual logging wells and the Greenberg-Castagna empirical formula, the corresponding measured rotation prediction parameters were calculated, so that the actual measurement and prediction can be achieved. The error rate of the curve is within 5%, and the calculation formula conforming to this area is obtained, and the shear wave curve prediction method based on the geological parameters of P-wave and porosity and permeability is established; Width to length ratio = 0.1, formation water salinity 6000ppm;

③ Through the shear wave curve prediction method, the shear wave curve prediction based on the longitudinal wave, porosity and permeability geological parameters is realized, and the well shear wave curve is obtained;

④ Collect the logging curve data of 20 wells in the block including density, and prepare the basic elastic parameter curve required for inversion;

The second step is to prepare the seismic data volume required for inversion;

This step is achieved through the following paths:

① Collect pre-stack seismic CRP gather data that can achieve full coverage of the block, and perform three seismic processes, including Fourier transform to eliminate random noise, Radon transform to eliminate interlayer multiples, and normalization by obtaining The energy compensation of different offset distances is carried out with the factor, and the pre-stack seismic CRP gathers are obtained after processing;

② Carry out CRP gather forward modeling for the measured shear wave wells;

③ Combined with the horizon calibration results of the target layer, collect the post-processing pre-stack seismic CRP gathers of the measured shear-wave well positions, compare the post-processing pre-stack seismic CRP gathers with the measured shear-wave well forward CRP gathers, and observe the amplitude variation trend, that is, AVO Whether the characteristics are the same, after comparison, with the increase of the incident angle, the amplitude of the target layer decreases, and the change trend of the two is the same, indicating that the processing results are effective, the signal-to-noise ratio of the seismic data after processing is improved, the wave group characteristics are clear, and the effective frequency is increased by 5 Hz;

④ Analyze the top and bottom range of the target layer according to the horizon calibration results, and determine the gathers within the range of the incident angle of 35° as valid gathers; remove the seismic information with low signal-to-noise ratio in the far and near traces. The above-mentioned near pass, that is, the incident angle is less than 1°; the CRP sub-angle segment scheme is determined, and the angle segment range is 5 segments, which are: 1～7°, 8～14°, 15～21°, 22～28°, 29～35° ;

⑤ The processed CRP gathers are divided into 5 angle segments and superimposed respectively to obtain 5 post-stack seismic data volumes with different incident angle ranges;

The third step is to prepare the plates required for the geological interpretation of the elastic parameter inversion results;

This step is achieved through the following paths:

① For the 6 measured shear wave wells, the skeleton geological model of the area was established by using the well lithological geological parameters and the longitudinal and shear wave curves. The well lithological geological parameters were the interpretation data of logging lithology and water saturation. Well continuous lithology and water saturation interpretation results;

② Perform fluid replacement analysis on the skeleton geological model. From water-saturated to oil-saturated, the curve change characteristics of basic elastic parameters are clarified. The basic elastic parameters include density, P-wave impedance, and shear-wave impedance; the reservoir fluid in this area changes from water-saturated to oil-saturated During the process, the density becomes smaller, the longitudinal wave impedance becomes smaller, and the shear wave impedance remains unchanged, and the fluid properties can be further identified by the response difference of the three;

③ With the change of the fluid properties of the reservoir, the density curve in this area changes by 12%, the P-wave impedance changes by 15%, and the shear-wave impedance changes within 1%. The lithology, water saturation and 3 This kind of elastic parameter relationship chart, that is, put the uphole elastic parameter value and the logging interpretation conclusion into the same chart, according to the rule that the overlap between the favorable area and the background area is less than 10%, determine the optimal elastic parameter or Parameter combination; favorable area refers to the area with high oil content and low water saturation, and the background area refers to other areas; this area is determined to adopt the combination of three parameters, namely the ratio of longitudinal and transverse waves, the impedance of longitudinal waves, and the density as the optimal elastic parameters.

利用步骤③优选的地震敏感弹性参数——纵横波比、纵波阻抗和密度3个参数组合，建立其与地下岩性、饱和度对应关系；根据区块地质认识，在地质上划定含水饱和度＜55%为富含油砂岩有利区，对应纵横波比＜1.9，纵波阻抗＜6700g/cm³·m/s，密度＜2.16 g/cm³，实现从地震到地质的解释，弹性参数反演成果地质解释所需的图版准备完毕；本区密度和含水饱和度关系拟合公式如下：

Using the combination of three parameters of seismic sensitive elastic parameters, namely the ratio of longitudinal and transverse waves, the impedance of longitudinal waves and the density, the corresponding relationship with the underground lithology and saturation is established; according to the geological knowledge of the block, the water saturation is delineated geologically. <55% is the favorable area rich in oil sandstone, corresponding to the ratio of compressional to shearing wave <1.9, the impedance of compressional wave <6700g/cm ³ ·m/s, the density < 2.16 g/cm ³ , realizing interpretation from seismic to geology, inversion of elastic parameters The plates required for the geological interpretation of the results have been prepared; the fitting formula for the relationship between density and water saturation in this area is as follows:

Water saturation=1.24×density-2.36 (Formula 1)

The fourth step is to perform pre-stack simultaneous geostatistical inversion, improve the resolution of reservoir interpretation, and perform lithologic interpretation to obtain lithologic bodies;

The specific implementation path of this step is as follows:

① Using the curve data of the three basic elastic parameters obtained in the first step and the five processed seismic data volumes obtained in the second step, carry out the conventional process of pre-stack simultaneous geostatistical inversion, and obtain the three basic elastic parameters— - the post-stack parametric volume of longitudinal wave impedance, shear wave impedance and density;

② In the process of lithology interpretation in this area, considering that the density is the high accuracy of the logging curve, the P-wave impedance is extracted from the seismic well side channel, and the shear-wave curve is the calculation curve. Finally, the density post-stack parameter volume is used as the basic data from elasticity to geology. body;

③ Use the interpretation chart obtained in the third step to interpret elastic parameters to geological parameters, and use the relationship between density and lithology to directly convert the density body into a three-dimensional lithologic body;

In the fifth step, on the basis of the three-dimensional lithologic body obtained in the fourth step, the well water saturation interpretation results during the seismic acquisition period are added, and the configuration co-simulation process is performed to obtain a three-dimensional water saturation volume;

The specific implementation path of this step is as follows:

① Screen the well water saturation interpretation results during the seismic acquisition period. The well water saturation interpretation results during the seismic acquisition period are the drilling results within 5 years between the drilling time and the seismic acquisition period. The consistency of the results, there are 12 wells in this block, the water saturation calculated by this method is the water saturation of the underground reservoir during the seismic acquisition period, and for the local undeveloped area, it is the original water saturation;

②Using the results of the water saturation interpretation curves of 12 wells as the first variable, and using the three-dimensional lithologic body obtained in the fourth step as the second variable, perform configuration co-simulation to establish a three-dimensional water saturation volume in this area;

The sixth step is to determine the oil-water transition zone range through the obtained water saturation volume;

The specific implementation path of this step is as follows:

①According to the relative permeability curve relationship established by the coring data of the target layer in the development zone, the water saturation range of pure oil and pure water production in the oil layer is defined; the average permeability of the reservoir in this area is 200mD, and the average porosity is 22%. Relative permeability measured curve, water saturation < 35% to produce pure oil, water saturation > 71% to produce pure water, and water saturation between 35% to 71% to produce both oil and water;

②Using the three-dimensional water saturation volume of this area obtained in the fifth step, according to the requirements of the water saturation range, the pure oil-producing and pure water-producing areas are calibrated in three-dimensional space; the bottom of pure oil production is the oil bottom, the pure water The top of the water is the water top. Considering the heterogeneity of the underground reservoir, the surface containing more than 90% of the pure oil-producing layer and the surface containing more than 90% of the pure water-producing layer are respectively delineated in three-dimensional space, between the two surfaces. That is, the oil-water transition zone. This area is a typical structural oil reservoir. According to the calibration results, the structural plane with an altitude >-1060m is the pure oil-producing area, the structural plane with an altitude <-1080m is the pure water-producing area, and there is oil and water between the two. The scope of the transition zone, the calibration of the oil-water transition zone in this area has been completed. The results can quickly and effectively guide the expansion of the old oilfields and the increase of reserves, and the construction of new areas with benefits.

In a nutshell, the position of the oil-water transition zone is the basis for the calibration of oilfield reserves and is of great significance to oilfield exploration and development. The old research methods all need to have more well data in the study area, even the data of coring wells and oil test wells as the research basis. These methods are expensive and are not suitable for the area without wells at the edge of the oilfield. The non-well area is an important target area for future reserve increase research in the oilfield, and there has been a lack of practical methods to determine the oil-water transition zone.

However, an oil saturation inversion method based on pre-stack seismic data constructed in the present invention is, in short, the interpretation results of oil saturation in oil layers obtained from a small number of wells in a well area, and the results obtained by pre-stack seismic inversion. A conversion relationship is established for the density elastic parameters (because there is a natural density difference between oil and water), and then the three-dimensional saturation volume of the reservoir is obtained through seismic inversion of the density volume, so as to achieve effective calibration of the oil-water transition zone in no well area. be successful.

The substantive comparison between the old and new methods is as follows: in terms of implementation conditions, the new method can use existing wells, while the old method requires a certain number of wells in the study area, and the implementation of oil testing, coring and other work. The 3D seismic data used in the new method has generally been collected in the expansion area adjacent to the oil field, and there is no data problem.

In terms of results and benefits, the old method must use drilling to realize edge detection, which makes the success rate of early edge exploration wells low; the new method can establish an understanding of the spatial distribution of oil and water in the oil-water transition zone through preliminary research, and guide the selection of drilling well locations. , so that the success rate of edge expansion wells is improved and investment is saved.

Claims (1)

1. An oil-water transition zone range determining method based on seismic inversion comprises the following steps:

firstly, preparing a basic elastic parameter curve required by inversion; the basic elastic parameter curve comprises a transverse wave curve, a density curve and longitudinal wave impedance;

the steps are realized through the following paths: determining whether the seismic data collected by the block contain transverse wave curve information, if so, directly utilizing the transverse wave curve information; if not, acquiring multi-level array acoustic logging information of 1 to 2 well target layers in a developed area to obtain a transverse wave curve of an actually measured well; establishing a transverse wave curve based on longitudinal wave and hole penetration geological parameters by utilizing an actually measured transverse wave curve and through a Greenberg-Castagna empirical formula; in addition to the shear wave curve, the density curve is obtained through well logging actual measurement, and the longitudinal wave impedance is obtained through seismic acquisition; after preparation of a basic elastic parameter curve required by inversion is finished, summarizing the basic elastic parameter curve required by inversion, wherein the density is obtained through well logging actual measurement, the longitudinal wave impedance is acquired through earthquake, and the transverse wave impedance is an empirical formula estimation curve;

the data for analysis in this step includes: seismic data volume, multi-stage array acoustic logging data, well point hole permeability geological parameters and density logging curve data; wherein, the seismic data volume selects three-dimensional seismic data; selecting actual measurement data of wells in a block from the multi-stage array acoustic logging data; well logging interpretation result data of wells in the block is selected from the well point hole permeability geological parameter data, the data need to be continuous interpretation results and cannot be segmented interpretation results; selecting a logging curve of a well in a block from the density logging curve data;

secondly, preparing a seismic data volume required by inversion;

the steps are realized through the following paths:

(1) starting from pre-stack seismic CRP gather data, performing three seismic processing including denoising, removing multiples and energy compensation at different offset distances;

(2) performing CRP gather forward modeling on the actually measured transverse wave well;

(3) comparing the processed pre-stack earthquake CRP gather with the actual measurement transverse wave well forward modeling CRP gather by combining the target layer position calibration result, observing whether the amplitude variation trends, namely AVO characteristics, are the same or not, repeating the process (1) if the amplitude variation trends are different, and performing the process (4) if the amplitude variation trends are the same;

(4) analyzing a target stratum range according to a horizon calibration result, and determining a CRP (common reflection point) angle section scheme, wherein the angle section range is 3-5 sections, seismic information with low signal-to-noise ratio of a far channel and a near channel needs to be removed, the far channel is an incidence angle of more than 35 degrees, the near channel is an incidence angle of less than 1 degree, and the whole target stratum needs to be covered;

(5) stacking the processed CRP gathers in 3-5 angle ranges respectively to obtain a plurality of stacked seismic data volumes with different angle ranges;

the data for analysis in this step includes: pre-stack seismic CRP gather data, target layer position calibration results and well forward CRP gather results; the method comprises the following steps that pre-stack earthquake CRP gather data are selected to obtain result data capable of realizing full coverage of a plane and a longitudinal range of a research area, a target layer position calibration result is selected to obtain a position calibration result at least comprising a target layer top-bottom range and a main mark layer, and a well forward CRP gather result is selected to obtain a CRP gather result of a target interval of a measured transverse wave well in the research area;

thirdly, preparing a chart required by the elastic parameter inversion result geological interpretation;

the steps are realized through the following paths:

(1) for an actually measured transverse wave well, establishing a skeleton geological model by using well lithology geological parameters and longitudinal and transverse wave curves;

(2) performing fluid replacement analysis on the skeleton geological model, and determining the change characteristics of a basic elastic parameter curve from water saturation to oil saturation, wherein the basic elastic parameters comprise density, longitudinal wave impedance and transverse wave impedance; if the variation range of the basic elastic parameter curve is lower than 2 percent, the method is not applicable;

(3) for the blocks with the basic elastic parameter curve variation amplitude larger than 5%, further establishing a chart of the relation between the lithology and the water saturation on the well and each elastic parameter, namely putting the values of the elastic parameter on the well and the well logging interpretation conclusion into the same chart, and determining the optimal elastic parameter or parameter combination for distinguishing the lithology and the saturation according to the rule that the overlapping range of the favorable area and the background area is smaller than 10%; the favorable area refers to an area with high oil content and low water saturation, and the background area refers to other areas;

establishing a corresponding relation between the seismic sensitive elastic parameters optimized in the step (3) and the underground lithology and the saturation, and performing the explanation from the earthquake to the geology, wherein the preparation of a chart required by the inversion result geology explanation of the elastic parameters is finished;

the extraction data source used in this step includes: actually measuring transverse wave well curve data, well logging lithology interpretation data, well logging water saturation interpretation data and well elasticity parameter curves; wherein, the actual measurement transverse wave well curve data selects the actual measurement transverse wave well in the block, the well logging lithology and water saturation explanation data selects the well logging continuous lithology and water saturation explanation results in the block, and the well elastic parameter curve uses the transverse wave impedance, longitudinal wave impedance and density curve obtained in the first step;

fourthly, performing prestack simultaneous geostatistical inversion, and performing lithology explanation to obtain a lithologic body;

the specific implementation path of the step is as follows:

(1) performing a pre-stack simultaneous geostatistical inversion routine by using the basic elastic parameter curve data obtained in the first step and the seismic data volume data obtained in the second step to obtain a post-stack parameter volume of three basic elastic parameters, namely longitudinal wave impedance, transverse wave impedance and density;

(2) using the density parameter volume as a base data volume of elasticity to geology;

(3) using the chart obtained in the third step to explain the elasticity to the geology, and using the relation between the density and the lithology to directly convert the density body into a three-dimensional lithology body;

fifthly, carrying out configuration co-simulation to establish a water saturation body;

the specific implementation path of the step is as follows: adding a well water saturation explanation result in an earthquake acquisition period on the basis of the three-dimensional lithologic body obtained in the fourth step, and performing configuration co-simulation flow to obtain a three-dimensional water saturation body; the well water saturation interpretation result in the seismic acquisition period selects wells with the distance between the drilling time and the seismic acquisition period within 5 years, and the water saturation calculated by the method is reflected by the water saturation of the underground reservoir in the seismic acquisition period;

sixthly, determining the range of the oil-water transition zone according to the obtained water saturation body, wherein the specific implementation path is as follows:

(1) determining the water saturation value range of pure oil and pure water produced in an oil layer according to a relative permeability relation established by target layer coring data in a development area; selecting relative permeability relation data established by a target layer core well in a research area from the relative permeability relation data;

(2) and utilizing the three-dimensional water saturation body obtained in the fifth step, and according to the requirement of the water saturation value range, calibrating the bottom of the produced pure oil, namely the oil bottom, and the top of the produced pure water, namely the water top, in a three-dimensional space, wherein the two spaces are the oil-water transition zone range, and finishing the oil-water transition zone range calibration work.

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