阅读说明：本技术 一种强地震反射界面下的小尺度缝洞信息凸显方法 (Small-scale slot and hole information highlighting method under strong seismic reflection interface ) 是由 李宗杰 李海英 文山师 杨子川 韩勇 石媛媛 洪才均 李弘艳 吴鲜 张�荣 于 2018-08-01 设计创作，主要内容包括：本发明公开了一种强地震反射界面下的小尺度缝洞信息凸显方法。在本发明的方法中,针对包含强反射界面干扰的地震数据,在保证子波稳定的条件下,通过重构反射系数生成凸显小尺度缝洞信息的地震数据体。根据本发明的方法,可以有效弱化强反射界面对储层地震信息的掩盖,突出储层地震响应特征,从而提高储层预测精度和钻井成功率,为指导钻井的部署提供有力的数据支持。(The invention discloses a small-scale slot and hole information highlighting method under a strong seismic reflection interface. In the method, aiming at the seismic data containing strong reflection interface interference, a seismic data body for highlighting small-scale slot and hole information is generated by reconstructing a reflection coefficient under the condition of ensuring wavelet stability. According to the method, the covering of the strong reflection interface on the reservoir seismic information can be effectively weakened, and the reservoir seismic response characteristics are highlighted, so that the reservoir prediction precision and the drilling success rate are improved, and powerful data support is provided for guiding the deployment of drilling.)

1. A small-scale slot and hole information highlighting method under a strong seismic reflection interface is characterized in that a seismic data body for highlighting small-scale slot and hole information is generated by reconstructing a reflection coefficient under the condition of ensuring wavelet stability aiming at seismic data containing strong reflection interface interference.

2. The method of claim 1, wherein generating a seismic data volume highlighting small-scale hole information by reconstructing reflection coefficients comprises:

calculating a first reflection coefficient volume from the seismic data;

attenuating and weakening the strong interface reflection coefficient in the first reflection coefficient body, reserving other information, and reconstructing to obtain a second reflection coefficient body;

and constructing a seismic data volume after weakening the strong interface according to the second reflection coefficient volume.

3. The method of claim 2, wherein:

calculating a first reflection coefficient volume, wherein an average wavelet is calculated to invert the first reflection coefficient volume;

and according to the second reflection coefficient body, utilizing the average wavelet forward modeling to reconstruct a seismic data body, and obtaining the seismic data body after weakening a strong interface.

4. The method of claim 3, wherein the average wavelet is computed, wherein the real borehole fine synthetic seismic record is calibrated, the seismic wavelet for each well is extracted using the log wave impedance curve and the well-side seismic traces, and then the average wavelet is computed.

5. The method of claim 3 or 4, wherein said first reflection coefficient volume is inverted using a sparse pulse inversion algorithm.

6. The method of claim 3 or 4, wherein the first reflection coefficient volume is inverted using a spectral inversion algorithm.

7. The method of any of claims 3 to 6, wherein the average wavelet forward performance is used to reconstruct the seismic data volume, wherein statistical average wavelet convolution is used to attenuate the seismic data volume after a strong interface.

8. The method according to any one of claims 2 to 7, wherein attenuation of strong interface reflection coefficients in the first reflection coefficient volume is attenuated by giving a time window to the interpreted horizon of strong in-phase axes.

9. The method of claim 8, wherein, based on the horizons interpreted by the strong seismic interfaces, the corresponding time window is selected, and the reflection coefficient for the strong interfaces within the time window is multiplied by an attenuation factor.

10. A storage medium having program code stored thereon for implementing the method of any one of claims 1-9.

Technical Field

The invention relates to the field of geological exploration, in particular to a small-scale slot and hole information highlighting method under a strong seismic reflection interface.

Background

In the field of geological exploration, carbonate marine facies is a relatively common oil and gas reservoir geological structure. In many practical scenes, the Ordovician carbonate reservoir is mainly formed by cracks and caves and controlled by multiple factors such as fracture, sequence interfaces, hydrothermal solution and the like, and forms a mixed reservoir body which is mainly formed by superposition of multiple factors and modified by fracture control. The reservoir stratum has unobvious characteristics on the seismic profile, because the top surface of the reservoir stratum is a strong reflection interface, and weak reservoir stratum seismic response characteristics are annihilated in a strong reflection red wave trough homophase axis, thereby bringing great difficulty to reservoir stratum prediction.

In the prior art, for the interference of the strong reflection interface, a wavelet decomposition reconstruction technology is generally adopted, seismic data are decomposed into a series of wavelets with different frequencies and different energies, then the seismic wavelets corresponding to the strong reflection interface are removed in frequency and amplitude, and the reconstruction is performed by using the residual seismic wavelets. The method mainly comprises the following scheme.

And (3) a frequency difference wavelet decomposition reconstruction method: the technical idea of the method is that in the process of wavelet propagation, the shape of the wavelet can be changed due to energy diffusion, earth filtering, multiple waves, interference and the like, so that a certain section of stratum (corresponding to the reflection coefficient of a local sequence) corresponds to a wavelet. Multi-wavelet seismic trace decomposition the seismic trace is decomposed into a combination of seismic wavelets by a proprietary algorithm (US Patent Appl:11/382,042), the algebraic stacking of the group of seismic wavelets being the same as the seismic trace. After decomposing the multi-wavelet seismic channel into a group of wavelets, classifying and screening the wavelets through the dominant frequency of the wavelets, thereby extracting the wavelet information related to the research target, namely wavelet reconstruction, representing software Geocyber.

Energy difference wavelet decomposition reconstruction method: the technical idea also considers that the extracted seismic wavelets are different in different depths of the same seismic data. The specific implementation process is to decompose a given data segment in the input seismic data body into sub-wave components with different energies, and the sub-wave components with different energies are obtained through statistical calculation based on the input seismic data segment. The first energy component represents a wavelet having a maximum commonality, maximum energy, among all of the input seismic data segments; after removing the input data segment of the first energy component, the second component represents the wavelet component having the greatest commonality, greatest energy, among the remaining input data segments; the third component is the wavelet component … … with the greatest common, greatest energy in the seismic data segment remaining after the first and second components are removed, and so on, representing the software Geoscope.

However, due to the complexity of the geological environment, seismic data is often very complex and the volume of data is extremely large. The method in the prior art is adopted to eliminate the interference of the strong reflection interface, so that not only is huge and complicated data operation required, but also the final interpretation result can not meet the requirements on precision and stability.

Disclosure of Invention

The invention provides a small-scale slot and hole information highlighting method under a strong seismic reflection interface, aiming at seismic data containing strong reflection interface interference, and generating a seismic data body for highlighting small-scale slot and hole information by reconstructing a reflection coefficient under the condition of ensuring wavelet stability.

In one embodiment, a seismic data volume for highlighting small-scale fracture-hole information is generated by reconstructing reflection coefficients, comprising:

calculating a first reflection coefficient volume from the seismic data;

attenuating and weakening the strong interface reflection coefficient in the first reflection coefficient body, reserving other information, and reconstructing to obtain a second reflection coefficient body;

and constructing a seismic data volume after weakening the strong interface according to the second reflection coefficient volume.

In one embodiment:

calculating a first reflection coefficient volume, wherein an average wavelet is calculated to invert the first reflection coefficient volume;

and according to the second reflection coefficient body, utilizing the average wavelet forward modeling to reconstruct a seismic data body, and obtaining the seismic data body after weakening a strong interface.

In one embodiment, an average wavelet is computed, wherein the real borehole fine synthetic seismic record is calibrated, the seismic wavelet for each well is extracted using the log wave impedance curve and the well-side seismic traces, and then the average wavelet is computed.

In one embodiment, the first reflection coefficient volume is inverted using a sparse pulse inversion algorithm.

In one embodiment, the first reflection coefficient is inverted using a spectral inversion algorithm.

In one embodiment, the average wavelets are used to forward reconstruct the seismic data volume, wherein statistical average wavelets are used to convolve the seismic data volume after the forward performance weakens the strong interface.

In an embodiment, the strong interface reflection coefficients in the first reflection coefficient volume are attenuated by giving a time window to the interpretation horizon of the strong event.

In one embodiment, according to the layer position explained by the strong seismic interface, a corresponding time window is selected, and the reflection coefficient of the strong interface in the range of the time window is multiplied by an attenuation factor.

The invention also proposes a storage medium on which a program code implementing the method according to the invention is stored.

According to the method, the covering of the strong reflection interface on the reservoir seismic information can be effectively weakened, and the reservoir seismic response characteristics are highlighted, so that the reservoir prediction precision and the drilling success rate are improved, and powerful data support is provided for guiding the deployment of drilling.

Additional features and advantages of the invention will be set forth in the description which follows. Also, some of the features and advantages of the invention will be apparent from the description, or may be learned by practice of the invention. The objectives and some of the advantages of the invention may be realized and attained by the process particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a flow diagram of a method according to an embodiment of the invention;

FIGS. 2-5 are graphs illustrating the results of a single step according to one embodiment of the present invention;

FIG. 6 is a partially enlarged and contrasted view of a seismic section before and after data processing according to an embodiment of the present invention;

FIG. 7 is a graph comparing the rate of change of amplitude of seismic data before and after data processing according to an embodiment of the invention;

FIG. 8 is a graph comparing the raw data, the processing results according to an embodiment of the present invention, and the processing results according to the prior art.

Detailed Description

The following detailed description will be provided for the embodiments of the present invention with reference to the accompanying drawings and examples, so that the practitioner of the present invention can fully understand how to apply the technical means to solve the technical problems, achieve the technical effects, and implement the present invention according to the implementation procedures. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.

In the field of geological exploration, carbonate marine facies is a relatively common oil and gas reservoir geological structure. In many practical scenes, the Ordovician carbonate reservoir is mainly formed by cracks and caves and controlled by multiple factors such as fracture, sequence interfaces, hydrothermal solution and the like, and forms a mixed reservoir body which is mainly formed by superposition of multiple factors and modified by fracture control. The reservoir stratum has unobvious characteristics on the seismic profile, because the top surface of the reservoir stratum is a strong reflection interface, and weak reservoir stratum seismic response characteristics are annihilated in a strong reflection red wave trough homophase axis, thereby bringing great difficulty to reservoir stratum prediction.

In the prior art, for the interference of the strong reflection interface, a wavelet decomposition reconstruction technology is generally adopted, seismic data are decomposed into a series of wavelets with different frequencies and different energies, then the seismic wavelets corresponding to the strong reflection interface are removed in frequency and amplitude, and the reconstruction is performed by using the residual seismic wavelets. The method mainly comprises the following scheme.

And (3) a frequency difference wavelet decomposition reconstruction method: the technical idea of the method is that in the process of wavelet propagation, the shape of the wavelet can be changed due to energy diffusion, earth filtering, multiple waves, interference and the like, so that a certain section of stratum (corresponding to the reflection coefficient of a local sequence) corresponds to a wavelet. Multi-wavelet seismic trace decomposition the seismic trace is decomposed into a combination of seismic wavelets by a proprietary algorithm (US Patent Appl:11/382,042), the algebraic stacking of the group of seismic wavelets being the same as the seismic trace. After decomposing the multi-wavelet seismic channel into a group of wavelets, classifying and screening the wavelets through the dominant frequency of the wavelets, thereby extracting the wavelet information related to the research target, namely wavelet reconstruction, representing software Geocyber.

Energy difference wavelet decomposition reconstruction method: the technical idea also considers that the extracted seismic wavelets are different in different depths of the same seismic data. The specific implementation process is to decompose a given data segment in the input seismic data body into sub-wave components with different energies, and the sub-wave components with different energies are obtained through statistical calculation based on the input seismic data segment. The first energy component represents a wavelet having a maximum commonality, maximum energy, among all of the input seismic data segments; after removing the input data segment of the first energy component, the second component represents the wavelet component having the greatest commonality, greatest energy, among the remaining input data segments; the third component is the wavelet component … … with the greatest common, greatest energy in the seismic data segment remaining after the first and second components are removed, and so on, representing the software Geoscope.

However, due to the complexity of the geological environment, seismic data is often very complex and the volume of data is extremely large. The method in the prior art is adopted to eliminate the interference of the strong reflection interface, so that not only is huge and complicated data operation required, but also the final interpretation result can not meet the requirements on precision and stability.

Aiming at the problems in the prior art, the invention provides a small-scale slot hole information highlighting method under a strong seismic reflection interface.

As can be known from analysis of the prior art, the traditional wavelet decomposition reconstruction method considers that the seismic wavelets are changed, then filters the decomposition wavelets through characteristic differences such as frequency, amplitude and the like, and selects proper wavelets to reconstruct a seismic data volume.

However, by calibrating the synthetic seismic records in a plurality of regions, in the same work area, the same seismic data volume is obtained, the logging curve after environmental correction and the wavelets extracted by the seismic channels beside the well are basically consistent in form except for the subtle difference in amplitude, so that the large difference cannot be caused. The extracted wavelets are also difficult to be consistent with the Rake wavelets, and the wavelets side lobes are usually asymmetric but uniform.

That is to say, according to the calibration of a large number of synthetic seismic records, the wavelet forms extracted through the correlation between the logging curves and the well-side seismic channels are basically consistent under the condition that the stratum of the work area has no violent change, and the change is the reflection coefficient, so that the consistency processing thought of seismic data is met, and the geological mode is also met.

Therefore, the method of the present invention adopts a reflection coefficient reconstruction method or concept different from the conventional wavelet decomposition reconstruction technical concept. Specifically, under the condition of ensuring the stability of the wavelets, the seismic data volume for highlighting the small-scale slot-hole information is generated by reconstructing the reflection coefficient instead of reconstructing the wavelets.

According to the method, the covering of the strong reflection interface on the reservoir seismic information can be effectively weakened, and the reservoir seismic response characteristics are highlighted, so that the reservoir prediction precision and the drilling success rate are improved, and powerful data support is provided for guiding the deployment of drilling.

The detailed flow of a method according to an embodiment of the invention is described in detail below based on the accompanying drawings, the steps shown in the flow chart of which can be executed in a computer system containing instructions such as a set of computer executable instructions. Although a logical order of steps is illustrated in the flowcharts, in some cases, the steps illustrated or described may be performed in an order different than presented herein.

As shown in FIG. 1, in one embodiment, a seismic data volume for highlighting small-scale slot-hole information is generated by reconstructing reflection coefficients, comprising:

calculating a first reflection coefficient volume from the seismic data (S110);

attenuating and weakening the strong interface reflection coefficient in the first reflection coefficient body, reserving other information, and reconstructing to obtain a second reflection coefficient body (S120);

a seismic data volume with a weakened strong interface is constructed from the second reflection coefficient volume (S130).

Further, in one embodiment:

in step S110, an average wavelet is calculated to invert the first reflection coefficient volume;

in step S130, the average wavelet is used to forward reconstruct the seismic data volume according to the second reflection coefficient volume, and the seismic data volume with the weakened strong interface is obtained.

Further, in one embodiment, in step S110, the real-borehole fine synthetic seismic record is calibrated, seismic wavelets of each well are extracted by using the log wave impedance curve and the well-side seismic traces, and then an average wavelet is calculated.

Specifically, in one embodiment, in step S110, the first reflection coefficient is inverted by a sparse pulse inversion algorithm.

Specifically, in one embodiment, in step S110, the first reflection coefficient is inverted by a spectral inversion algorithm.

Specifically, in one embodiment, in step S130, the seismic data volume is reconstructed using the average wavelet forward evolution, wherein the seismic data volume after the strong interface is weakened is forward evolved using the statistical average wavelet convolution.

Specifically, in one embodiment, in step S120, attenuation weakening is performed on the strong interface reflection coefficient in the first reflection coefficient volume by giving a time window to the interpretation horizon of the strong event.

Specifically, in one embodiment, in step S120, a certain time window is selected according to the layer position interpreted by the strong seismic interface, and the reflection coefficient of the strong seismic interface within the time window is multiplied by the attenuation factor. Specifically, in one embodiment, the attenuation factor ranges from 0 to 1. Further, in an embodiment, the specific value of the attenuation factor is obtained by a test.

According to the method of the present invention, the present invention also provides a storage medium having stored thereon program code that implements the method of the present invention. According to the method provided by the invention, the influence of the strong reflected wave group can be effectively weakened, and the hidden tiny slot characteristic is highlighted.

The implementation details of the present invention are described in detail below based on specific application scenarios.

In one embodiment, the real-borehole fine synthetic seismic record is calibrated, and seismic wavelets of each well are extracted by using a logging wave impedance curve and well-side seismic traces. The resulting seismic profile is shown in FIG. 2, where the T74 horizon shows a strong reflective interface.

And calculating average wavelets, and inverting the reflection coefficient volume by using a sparse pulse inversion or spectrum inversion algorithm. The finally obtained reflection coefficient profile is shown in fig. 3, wherein the T74 horizon corresponds to a strong reflection interface.

According to the level explained by the strong seismic interface, selecting a corresponding time window (corresponding to the T74 level), and multiplying the reflection sparsity of the strong interface in the range of the time window by an attenuation factor. Thereby weakening the reflection coefficient of the interface and obtaining the reflection coefficient body after the strong interface is removed. The resulting reflectance profile is shown in FIG. 4, where the reflectance corresponding to the T74 horizon is removed.

And (4) reconstructing the seismic data volume by using the average wavelet forward modeling to obtain the seismic data volume weakening the strong reflection interface. The final acquired seismic profile is shown in fig. 5.

Comparing fig. 2 with fig. 5, the beads at the T74 level at well location 200 are not evident in fig. 2, and the beads at the T74 level at well location 500 are evident in fig. 5. That is, the reservoir information within the red wave trough is more prominent.

Specifically, as shown in fig. 6, fig. 6 is a partially enlarged comparison diagram of the T74 layer of fig. 2 and fig. 5 at the same position, and it can be seen in fig. 6 that the small-scale amplitude anomaly is more prominent.

Further, as shown in FIG. 7, FIG. 7 is a graph of amplitude rate of change of seismic data before and after data processing (0-100 ms amplitude rate of change contrast with downward interface T74). The left graph is the original seismic data amplitude change rate attribute graph, and the right graph is the seismic data amplitude change rate attribute graph processed by the method. It can be seen that the decomposed amplitude rate of change property largely eliminates the strong reflection interface from interfering with the amplitude rate of change of T74, as shown in the circle of fig. 7.

Further, as shown in fig. 8, fig. 8 shows, from top to bottom, the original seismic data after color weakening, the seismic data processed according to the method of the present invention, and the seismic data processed by the prior art method. In fig. 8, the top is the original seismic data with normal display scale, the abnormal amplitude in the red wave valley is basically not seen, after the color scale is weakened, the abnormal amplitude in the red wave valley can be seen but is not obvious, after the strong interface is removed by the new method, the rest information is consistent with the original seismic profile, the structure is not changed, the information of the reservoir in one room group is more prominent, and the traditional wavelet decomposition reconstruction method is used, the seismic profile has larger difference, the signal-to-noise ratio is lower, and the seismic response characteristic of the reservoir is not prominent.

In conclusion, according to the method provided by the invention, the covering of the strong reflection interface on the reservoir seismic information can be effectively weakened, and the reservoir seismic response characteristics are highlighted, so that the reservoir prediction precision and the drilling success rate are improved, and powerful data support is provided for guiding the deployment of drilling.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. There are various other embodiments of the method of the present invention. Various corresponding changes or modifications may be made by those skilled in the art without departing from the spirit of the invention, and these corresponding changes or modifications are intended to fall within the scope of the appended claims.