A method and system for favorable reservoir prediction under deposition cycle constraints

Abstract

The application provides a favorable reservoir prediction method and system under sedimentary cycle constraint, and the prediction method comprises the following steps: step 1, frequency extension processing of work area seismic data, and synthetic record calibration; step 2, according to rock-electricity characteristics, the sand body formation period is determined; step 3, the top and bottom of each sand body are interpreted, and sensitive attributes are extracted respectively; step 4, the amplitude attribute values corresponding to different period sandstone and mudstone are counted, and the sensitive attribute hollowing processing is carried out; step 5, the sensitive hollowing attribute is combined with the frequency extension seismic data to implement the sand body boundary; step 6, the correlation analysis of rock physical parameters and reservoir physical property parameters is carried out, the rock physical parameters with high correlation with physical properties are determined, and the physical property inversion is carried out. The problem that the favorable reservoir prediction cannot be carried out on the seismic profile is solved, and the improved inversion is combined with drilling and other data to accurately track and describe the favorable reservoir development area.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil exploration technology, in particular to a favorable reservoir prediction method and system under the constraint of sedimentary cycle. BACKGROUND

[0002] In recent years, great success has been achieved in the exploration of lithologic reservoirs in Shengli Oilfield, and lithologic reservoirs have become an important place for recent reservoir expansion. However, there is a lack of systematic research means for overall description using seismic data, and there are problems of "ineffective" reservoirs and description uncertainty. In order to further expand the oil and gas exploration space, a favorable reservoir prediction method under the constraint of sedimentary cycle has been formed.

[0003] The lithologic sedimentary body developed in the continental lake basin has fast lithofacies change and complex sedimentary body development. At present, the favorable reservoirs with shallow depth, large scale and easy to identify on the seismic data have been basically identified. Some deep reservoirs with unclear sedimentary understanding are difficult to understand the distribution characteristics of the favorable reservoirs directly from the interpretation of the seismic data and the conventional inversion result profiles. SUMMARY

[0004] In view of the above problems, the present application is proposed in order to provide a favorable reservoir prediction method and system under the constraint of sedimentary cycle which overcomes the above problems or at least partially solves the above problems.

[0005] According to one aspect of the present application, a favorable reservoir prediction method under the constraint of sedimentary cycle is provided, and the prediction method comprises:

[0006] Step 1, seismic data frequency extension processing in the work area, and synthetic record calibration;

[0007] Step 2, according to the rock-electricity characteristics, the sand body formation period is determined;

[0008] Step 3, the top and bottom of each sand body are interpreted, and the sensitive attributes are extracted respectively;

[0009] Step 4, the amplitude attribute values corresponding to different period sandstone and mudstone are counted, and the sensitive attribute hollowing processing is performed;

[0010] Step 5, the sensitive hollowing attribute is combined with the frequency extension seismic data to implement the sand body boundary;

[0011] Step 6, the rock physical parameter and the reservoir physical parameter correlation analysis are performed, the rock physical parameter with high correlation with the physical property is determined, and the physical property inversion is carried out.

[0012] Optionally, the step 1, the seismic data frequency extension processing in the work area, and the synthetic record calibration specifically comprises:

[0013] The frequency extension processing of the work area geological data significantly improves the longitudinal resolution compared with the conventional profile;

[0014] By discrete synthetic record calibration, the correspondence between lithology and seismic reflection characteristics is determined, and the describability probability of the reservoir on the frequency expansion seismic profile is analyzed.

[0015] Optionally, the step 2 specifically comprises: according to the litho-electric characteristics, sedimentary cycle analysis is carried out to determine the sand body formation period.

[0016] Optionally, the step 3 specifically comprises: interpreting the density to reach 50 m*50 m.

[0017] Optionally, the step 4 specifically comprises:

[0018] The amplitude attribute values corresponding to different period sandstones and mudstones are counted.

[0019] The threshold values of different period sandstones are determined according to the amplitude attribute values.

[0020] The sensitive attribute hollowing processing is carried out according to the threshold values.

[0021] Optionally, the step 6 specifically comprises:

[0022] The elastic parameters related to porosity are preferably inverted.

[0023] The shear wave logging and prestack gather data are used to establish a targeted rock physical model to estimate the shear wave, and the prestack elastic parameter inversion is carried out as a prior constraint to obtain the prediction result of the porosity.

[0024] Optionally, the prediction method further comprises: step 7, comparing and verifying the real drilled sand body properties of the wells participating in the inversion and the wells not participating in the inversion with the inversion results, and using the inversion and drilling data to accurately track and describe the favorable reservoir.

[0025] The application further provides a favorable reservoir prediction system under sedimentary cycle constraint, which applies the favorable reservoir prediction method under sedimentary cycle constraint.

[0026] The frequency expansion processing module is used for frequency expansion processing of seismic data in the working area, and synthetic record calibration.

[0027] The sand body formation period determination module is used for determining the sand body formation period according to the litho-electric characteristics.

[0028] The sand body interpretation module is used for interpreting the top and bottom of each period of sand body and extracting sensitive attributes respectively.

[0029] The hollowing processing module is used for counting amplitude attribute values corresponding to different period sandstone and mudstone, and performing sensitive attribute hollowing processing.

[0030] The sand body boundary implementation module is used for implementing sand body boundary by using sensitive hollowing attribute and seismic facies characteristics of the frequency extension seismic data.

[0031] The physical property inversion module is used for analyzing correlation between rock physical parameters and reservoir physical parameters, determining rock physical parameters with high correlation with physical properties, and developing physical property inversion.

[0032] Optionally, the prediction system further comprises:

[0033] The comparison and verification module is used for comparing and verifying actual drilled sand body physical properties of the well participating in inversion and the well not participating in inversion with the inversion result, and accurately tracking and describing the favorable reservoir by using the inversion and drilling data.

[0034] Optionally, the frequency extension processing module specifically comprises:

[0035] The frequency extension processing unit is used for frequency extension processing of the geological data of the work area, and the longitudinal resolution is obviously improved compared with conventional profiles.

[0036] The record calibration unit is used for calibrating by discrete synthetic records, determining the corresponding relationship between lithology and seismic reflection characteristics, and analyzing the describability probability of the reservoir on the frequency extension seismic profile.

[0037] The application provides a favorable reservoir prediction method and system under sedimentary cycle constraint, and the prediction method comprises the following steps: 1, frequency extension processing of the seismic data of the work area, and synthetic record calibration; 2, determining sand body formation period according to rock-electricity characteristics; 3, interpreting the top and bottom of each sand body, and extracting sensitive attributes respectively; 4, counting amplitude attribute values corresponding to different period sandstone and mudstone, and performing sensitive attribute hollowing processing; 5, implementing sand body boundary by using sensitive hollowing attribute and seismic facies characteristics of the frequency extension seismic data; and 6, analyzing correlation between rock physical parameters and reservoir physical parameters, determining rock physical parameters with high correlation with physical properties, and developing physical property inversion. The favorable reservoir prediction problem of the seismic profile is solved, and the favorable reservoir development area is accurately tracked and described by using the inversion and combining drilling data.

[0038] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, the specific embodiments of the application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following specifically describes the specific embodiments of the application. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0040] Figure 1 A flow chart of a favorable reservoir prediction method under sedimentary cycle constraint provided by an embodiment of the present application;

[0041] Figure 2 A schematic diagram of applying frequency extension data to calibrate a synthetic record provided by an embodiment of the present application;

[0042] Figure 3 A schematic diagram of dividing sand body stages according to rock and electricity characteristics in a specific embodiment of the present application;

[0043] Figure 4 A schematic diagram of amplitude attribute of each sand body stage in a specific embodiment of the present application;

[0044] Figure 5 A schematic diagram of statistics of sandstone and amplitude in a specific embodiment of the present application;

[0045] Figure 6 A schematic diagram of relationship between sandstone thickness and amplitude value in a specific embodiment of the present application;

[0046] Figure 7 A schematic diagram of fine delineation of sand body boundary in a specific embodiment of the present application;

[0047] Figure 8 A schematic diagram of reservoir physical property parameter inversion flow in a specific embodiment of the present application;

[0048] Figure 9 A schematic diagram of inversion result and well matching in a specific embodiment of the present application. DETAILED DESCRIPTION

[0049] Exemplary embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is to be understood that the present disclosure can be embodied in various forms without being limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0050] The terms "comprise" and "have" and any variations thereof in the specification and claims of the present application and the drawings are intended to cover not exclusive inclusion, for example, inclusion of a series of steps or units.

[0051] The technical solutions of the present application are described in further detail below with reference to the accompanying drawings and embodiments.

[0052] As Figure 1 shown, Figure 1 is a flow chart of a favorable reservoir prediction method under the constraint of a deposition cycle.

[0053] Step 101, seismic data in the work area is processed to expand the frequency, the longitudinal resolution is obviously improved, the corresponding relationship between the lithology and the seismic reflection characteristics is determined through the discrete synthetic record calibration, and the describability probability of the reservoir on the expanded frequency seismic profile is analyzed. In an embodiment, the three-dimensional seismic data of the study area has a narrow frequency band, a low main frequency, and a low signal-to-noise ratio in the target layer. By expanding the frequency to improve the longitudinal resolution, the wavelet of the synthetic record is more consistent with the well trace, and the relationship between the lithology and the seismic reflection characteristics is more clear, 80% of the sandstone corresponds to a strong axis, as shown in Figure 2 .

[0054] Step 102, the sedimentary cycle is analyzed through the rock-electricity characteristics, and the sand body formation period is determined in combination with the source system. In an embodiment, on the basis of step 101, the work area can be divided into five periods through the rock-electricity characteristics, as shown in Figure 3 .

[0055] Step 103, the top and bottom of each sand body are interpreted, the interpretation density reaches 50m*50m, the accuracy of the seismic interpretation is ensured, and the sensitive attribute is extracted. In an embodiment, on the basis of step 103, the top surface of the five sand bodies is finely interpreted, and the root mean square amplitude attribute is preferably extracted, as shown in Figure 4 .

[0056] Step 104, the amplitude attribute of the sandstone is counted, the sandstone threshold value is set, and the sand body boundary is finely described by using the amplitude attribute graph. In an embodiment, the five sand bodies in the study area correspond to different amplitude threshold values, as shown in Figure 5 , the 4th period AMP>4000, the 3rd period sand body AMP>6000, and the 2nd period sand body AMP>300; the sand body thickness has a positive correlation with the amplitude, as shown in Figure 6 .

[0057] Step 105, on the basis of steps 103 and 104, the sand body boundary is finely described by using the amplitude attribute graph and the seismic data according to the amplitude threshold value of each sand body. In an embodiment, according to the lowest threshold value of the sandstone, the hollow root mean square amplitude attribute and the expanded frequency seismic data are used to finely describe the sand body boundary, as shown in Figure 7 .

[0058] Step 106, the petrophysical parameters are combined with the reservoir physical property parameters to determine the petrophysical parameters related to the physical property, and inversion is performed; in an embodiment, the study area makes full use of the shear wave logging and pre-stack gather data, obtains the elastic parameter volume such as the longitudinal wave impedance, the shear wave impedance and the ratio of the longitudinal wave velocity to the shear wave velocity through the pre-stack simultaneous inversion technology, and the correlation between the ratio of the longitudinal wave velocity to the shear wave velocity and the porosity is determined through the petrophysical analysis, and finally the porosity data volume is converted from the inversion result of the ratio of the longitudinal wave velocity to the shear wave velocity, and the reservoir physical property prediction is realized, as shown in Figure 8

[0059] Step 107, the actual drilled sand body physical property of the well participating in the inversion and the well not participating in the inversion is compared and verified with the inversion result, and the inversion and the drilling data are used to accurately track and describe the favorable reservoir. In an embodiment, the coincidence degree between the actual drilled sand body physical property and the predicted sand body physical property in the study area is more than 80%, as shown in Figure 9 From the effect, the porosity inversion profile can identify the favorable reservoir, and solves the problem that the seismic profile cannot predict the favorable reservoir, and the favorable reservoir development area is accurately tracked and described by using the inversion and combining with the drilling data.

[0060] Beneficial effect: it is difficult to understand the distribution characteristics of the favorable reservoir from the interpretation of the seismic data and the conventional inversion result profile.

[0061] The above specific embodiments further specifically describe the purpose, technical scheme and beneficial effect of the present application, and it should be understood that the above is only the specific embodiment of the present application, and is not used to limit the protection scope of the present application, and 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 favorable reservoir prediction under depositional cycle constraints, characterized in that, The prediction method comprises: Step 1, frequency extension processing of seismic data in a work area, and calibration of a synthetic record; Step 2, according to rock-electricity characteristics, determining a sand body formation period; Step 3, interpreting a top and a bottom of each sand body period, and extracting sensitive attributes respectively; Step 4, statistically analyzing amplitude attribute values corresponding to different sandstone and mudstone periods, and performing sensitive attribute hollowing processing; Step 5, using sensitive hollowing attributes in combination with frequency extension seismic data seismic facies characteristics to determine a sand body boundary; Step 6, analyzing a correlation between rock physical parameters and reservoir physical parameters, determining a rock physical parameter with high correlation with physical properties, and performing physical property inversion.

2. A method of predicting a favorable reservoir under a sedimentary cycle constraint according to claim 1, wherein, The step 1, frequency extension processing of seismic data in a work area, and calibration of a synthetic record specifically comprises: Frequency extension processing of geological data in the work area, and longitudinal resolution is obviously improved compared with a conventional profile; By discrete synthetic record calibration, a corresponding relationship between lithology and seismic reflection characteristics is determined, and a describability probability of a reservoir on a frequency extension seismic profile is analyzed.

3. A method of predicting a favorable reservoir under a deposition cycle constraint according to claim 1, characterized by, The step 2, according to rock-electricity characteristics, determining a sand body formation period specifically comprises: according to rock-electricity characteristics, analyzing a sedimentary cycle, and determining a sand body formation period.

4. The method for predicting a favorable reservoir under a deposition cycle constraint according to claim 1, wherein, The step 3, interpreting a top and a bottom of each sand body period specifically comprises: interpreting a density of 50 m*50 m.

5. The method for favorable reservoir prediction under depositional cycle constraint of claim 1, wherein, The step 4, statistically analyzing amplitude attribute values corresponding to different sandstone and mudstone periods, and performing sensitive attribute hollowing processing specifically comprises: Statistically analyzing amplitude attribute values corresponding to different sandstone and mudstone periods; According to the amplitude attribute values, a threshold value of different sandstone periods is determined; According to the threshold value, sensitive attribute hollowing processing is performed.

6. The method for favorable reservoir prediction under depositional cycle constraint of claim 1, wherein, The step 6, analyzing a correlation between rock physical parameters and reservoir physical parameters, determining a rock physical parameter with high correlation with physical properties, and performing physical property inversion specifically comprises: Optimizing elastic parameters related to porosity for inversion; Using shear wave logging and prestack gather data, a targeted rock physical model is established to estimate the shear wave, and is used as a prior constraint for prestack elastic parameter inversion to obtain a prediction result of porosity.

7. The method for favorable reservoir prediction under depositional cycle constraint of claim 1, wherein, The prediction method further comprises: step 7, comparing and verifying a real drilled sand body property of a well participating in inversion and a well not participating in inversion with an inversion result, and using inversion and drilling data to accurately track and describe a favorable reservoir.

8. A system for predicting favorable reservoirs under the constraint of depositional cycles, applying the method for predicting favorable reservoirs under the constraint of depositional cycles according to any one of claims 1 to 7, characterized in that, The prediction system comprises: A frequency extension processing module for frequency extension processing of seismic data in a work area, and calibration of a synthetic record; A sand body formation period determination module for determining a sand body formation period according to rock-electricity characteristics; A sand body interpretation module for interpreting a top and a bottom of each sand body period, and extracting sensitive attributes respectively; A hollowing processing module for statistically analyzing amplitude attribute values corresponding to different sandstone and mudstone periods, and performing sensitive attribute hollowing processing; A sand body boundary determination module for using sensitive hollowing attributes in combination with frequency extension seismic data seismic facies characteristics to determine a sand body boundary; A physical property inversion module for analyzing a correlation between rock physical parameters and reservoir physical parameters, determining a rock physical parameter with high correlation with physical properties, and performing physical property inversion.

9. A system for favorable reservoir prediction under depositional cycle constraints as claimed in claim 8 wherein, The prediction system further comprises: A comparison and verification module for comparing and verifying a real drilled sand body property of a well participating in inversion and a well not participating in inversion with an inversion result, and using inversion and drilling data to accurately track and describe a favorable reservoir.

10. A system for favorable reservoir prediction under depositional cycle constraints as claimed in claim 8 wherein, The frequency extension processing module specifically comprises: A frequency extension processing unit, which is used for frequency extension processing of the geological data of the work area, and the longitudinal resolution is obviously improved compared with conventional profiles; A record calibration unit, which is used for calibrating the discrete synthetic records, determining the corresponding relationship between the lithology and the seismic reflection characteristics, and analyzing the describability probability of the reservoir on the frequency extension seismic profile.

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