A method and apparatus for thin-bed seismic horizon interpretation

Abstract

The application discloses a thin layer seismic horizon interpretation method and device, wherein the method comprises the following steps: calibrating a synthetic seismogram; determining the position of reservoir top and bottom interfaces, the position of reservoir internal small layer top interfaces and seismic instantaneous phase; interpreting relatively stable seismic events within the range of reservoir top and bottom interfaces; counting the variation trend characteristics of stratum thickness; statistically analyzing seismic attributes which can reflect stratum structure and stratum thickness variation as trend attributes; taking the calibration result and the seismic instantaneous phase as reference standards, and taking the seismic attributes as horizontal trend constraint data to determine the seismic horizon interpretation between wells and outside each well. The application can break through the limitation of seismic longitudinal resolution, and the interpretation result is consistent with the calibration result of the well point synthetic seismogram, has a good matching relationship with the seismic reflection characteristics, and the horizontal variation characteristics of the seismic instantaneous phase of the interpretation result conforms to the geological law.

Description

Technical Field

[0001] This invention relates to a method and apparatus for interpreting thin-layer seismic horizons, belonging to the field of petroleum geological exploration and development technology. Background Technology

[0002] Using seismic data for seismic horizon interpretation to describe subsurface structural features is currently a crucial method for obtaining subsurface stratigraphic information. As oilfields enter the development phase, the precision requirements for studying reservoirs and their inner layers become increasingly stringent. These inner layers are generally quite thin, below the vertical resolution of seismic data, making it difficult to effectively distinguish the top and bottom interfaces. However, accurate horizon interpretation is key to better understanding the corresponding structures. Therefore, how to conduct seismic horizon interpretation of inner layers during the oilfield development phase has become a pressing technical challenge that urgently needs to be addressed. Summary of the Invention

[0003] To address the high-precision requirements of studying internal layers within oilfields during the development phase, and the problem that seismic resolution cannot meet the requirements for seismic horizon interpretation of internal layers within oilfields, this invention provides a method and apparatus for thin-layer seismic horizon interpretation.

[0004] This invention provides a method for interpreting thin-layer seismic horizons, including:

[0005] Synthetic seismic records were calibrated for wells in the study area based on well logging and seismic data.

[0006] Based on the calibration results of the synthetic seismic records, the location of the top and bottom interfaces of the reservoir, the location of the top interface of the internal sub-layers of the reservoir, and the corresponding instantaneous seismic phase are determined.

[0007] Within the range of the top and bottom interfaces of the reservoir, relatively stable seismic phase axes are interpreted to obtain relevant seismic properties;

[0008] Based on drilling geological stratification data, the variation trend characteristics of formation thickness in all wells were statistically analyzed.

[0009] Based on the aforementioned trend characteristics, statistical analysis is used to identify seismic attributes that reflect changes in stratigraphic structure and stratigraphic thickness as trend attributes.

[0010] Using the calibration results and the instantaneous phase of the earthquake as reference standards, and the earthquake attributes as lateral trend constraint data, the interpretation of seismic horizons between wells and outside each well is determined.

[0011] Another aspect of the present invention provides a thin-layer seismic horizon interpretation apparatus, comprising:

[0012] The calibration module is used to calibrate the synthetic seismic records of wells in the study area based on well logging data and seismic data, respectively.

[0013] The determination module is used to determine the location of the top and bottom interfaces of the reservoir, the location of the top interface of the internal sub-layers of the reservoir, and the corresponding instantaneous phase of the seismic data based on the calibration results of the synthetic seismic record.

[0014] The attribute module is used to interpret relatively stable seismic phase axes within the range of the top and bottom interfaces of the reservoir in order to obtain relevant seismic attributes;

[0015] The statistics module is used to statistically analyze the variation trend characteristics of formation thickness in all wells based on the location of the top and bottom interfaces of the reservoir and the location of the top interface of the internal sub-layers of the reservoir.

[0016] The analysis module, based on the aforementioned trend characteristics, statistically analyzes seismic attributes that reflect changes in stratigraphic structure and thickness as trend attributes; and

[0017] The interpretation module is used to determine the interpretation of seismic horizons between wells and outside each well, using the calibration results and the instantaneous phase of the earthquake as reference standards and the seismic attributes as lateral trend constraint data.

[0018] This invention interprets seismic stratigraphy by conducting seismic stratigraphic analysis of reservoirs and inner layers during the oilfield development stage. The seismic stratigraphic analysis results can overcome the limitations of vertical seismic resolution. The analysis results are consistent with the wellpoint synthetic seismic record calibration results and have a good matching relationship with seismic reflection characteristics. The lateral variation characteristics of the seismic instantaneous phase in the analysis results conform to geological laws.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures described in the written description, claims, and drawings.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 An implementation diagram of the thin-layer seismic horizon interpretation method provided in this embodiment of the invention;

[0023] Figure 2This is a schematic diagram of the thin-layer seismic horizon interpretation device provided in an embodiment of the present invention. Detailed Implementation

[0024] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to 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 disclosure to those skilled in the art.

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0026] After searching the literature, the inventor found that previous researchers had also done some research on this problem, such as proposing the integrated technology concept of well (earthquake) (oil reservoir) (simulation) (Ganli Deng et al., Petroleum Geophysical Exploration, Vol. 55, No. 5, pp. 617-639), but there were no practical and feasible technical methods for the problem studied in this patent.

[0027] Specifically, there are two main existing technical solutions:

[0028] (1) Determine the calibration location of the top and bottom interface of the thin layer by synthesizing seismic records, and comprehensively judge the typical characteristics of the seismic interpretation of the target layer: peak-to-peak value, trough-to-peak value, peak-to-trough transition surface, trough-to-peak transition surface, and interpret the top and bottom of the thin layer according to the typical characteristics.

[0029] However, the interpretation results of this method are inconsistent with the well point calibration results on the profile, and the interpreted formation thickness plane trend is inconsistent with the well point geological thickness trend.

[0030] (2) Thin layers are interpreted by proportional splitting and well point correction.

[0031] However, the interpretation results of this method lack evidence for the interpretation of seismic horizons between wells and in areas without wells.

[0032] Therefore, this invention proposes a thin-layer seismic horizon interpretation method by integrating well logging data and seismic data, including the following steps ① to ⑥, as follows: Figure 1The figure shown is an implementation diagram of the thin-layer seismic horizon interpretation method provided in this embodiment of the invention. The labels ①, ②, ③, ④, ⑤, and ⑥ in the figure correspond one-to-one with the following steps ① to ⑥.

[0033] ① Based on well logging data and seismic data, conduct synthetic seismic record calibration and simultaneously compare the calibration results of synthetic seismic records from well to well, so as to improve the consistency of calibration results between wells.

[0034] Among them, synthetic seismic record calibration refers to the calibration of seismic horizons in synthetic seismic records. Specifically, existing software can be used to carry out the relevant calibration. Since seismic data is time-domain data and well logging data is depth-domain data, it is necessary to establish a "bridge" between time-domain seismic data and depth-domain well logging data through sonic data—establishing a correspondence—and then determining the geological significance of different locations in the time-domain seismic data.

[0035] Well logging data consists of actual measurements taken in the wellbore, with depth as the vertical scale. Seismic data, on the other hand, is acquired using instruments, with time as the vertical scale. A one-to-one correspondence between depth and time is established through synthetic seismic records, thereby determining the characteristics of well-logged geological stratification corresponding to earthquake locations. Synthetic seismic records are seismic records (seismic traces) artificially synthesized from sonic logging or vertical seismic profile data.

[0036] The term "connecting wells" refers to linking adjacent wells together to cross-verify calibration results, improving the consistency between different wells and enhancing the quality of calibration. The specific verification process involves checking geological stratification results. If inconsistencies arise between wells, such as sudden changes in formation thickness or seismic phase, adjustments to the geological stratification are necessary, or the result may be due to abrupt changes in lithology.

[0037] Because a large number of wells are drilled during the development phase, it is crucial to ensure consistency and coordination between wells in the calibration results of the synthetic seismic records.

[0038] ②Based on the calibration results of synthetic seismic records, the location of the reservoir top and bottom interfaces and the top interface of the reservoir internal sub-layers are determined, along with the instantaneous phase of the seismic data, serving as the basis and reference standard for well point interpretation.

[0039] ③ Within the reservoir top and bottom interface range calibrated by the synthetic seismic record, the relatively stable seismic phase axes are interpreted in detail and used as a trend attribute in step ④.

[0040] The refined interpretation is reflected in the fact that the interpretation process is based on the characteristics of amplitude and phase, rather than being arbitrary. Stable seismic phase axes exhibit relative determinism during the interpretation process.

[0041] ④ Statistical analysis of the variation trend of formation thickness in well drilling.

[0042] Specifically, based on drilling geological stratification data, the lateral variation characteristics of the formation thickness of the corresponding reservoirs and inner layers within the reservoirs are statistically analyzed for all drilled wells. The drilling geological stratification data serves as the foundational data for drilling operations and is the result of geological stratification analysis conducted by geologists and geophysicists before drilling commences.

[0043] ⑤ Based on the aforementioned trend characteristics, statistical analysis is used to identify seismic attributes that reflect changes in stratigraphic structure and stratigraphic thickness as trend attributes.

[0044] The trend attributes include: seismic reflection phase axis trend, longitudinal stable phase axis stratigraphic thickness trend, and seismic amplitude trend. Since there are various seismic trends, and not every trend can reflect the lateral variations in stratigraphic structure and seismic thickness, a systematic analysis is necessary.

[0045] ⑥ Using the calibrated locations of each layer and the instantaneous phase of the seismic phase in the synthetic seismic record of the well as the trend seismic attributes (i.e., seismic attributes) of the statistical analysis results in step ⑤ as the lateral trend constraint data, the seismic interpretation of the seismic layers between and outside the well is determined, so as to meet the interpretation requirements of thin seismic layers in the oilfield development stage.

[0046] Using trend seismic properties as constraints helps ensure the relatively stable change of the instantaneous phase of seismic events in the well-to-well misalignment interpretation.

[0047] During the oilfield development phase, well point data is essential for understanding underground geological conditions, and there are relative blind spots between wells. Drilling data refers to logging data at the drilling location, including electrical logging (sonic, density, gamma, etc.), as well as logging and coring data.

[0048] Because seismic data exists between wells (seismic data is characterized by low vertical accuracy but richer lateral information containing geological features between wells), and by referencing the lateral characteristics and trends of seismic data, a detailed study is conducted on the blind areas between wells to infer the geological features between wells and in areas without wells. The interpretation results of seismic horizons of the reservoir and its inner layers match the wellpoint synthetic seismic record calibration results and conform to the characteristics of seismic trends, indicating that the seismic horizon interpretation results are good.

[0049] The method described in this embodiment performs seismic stratigraphic interpretation of the reservoir and its internal sub-layers during the oilfield development stage. The interpretation results overcome the limitations of vertical seismic resolution, exhibit consistency with well-point synthetic seismic record calibration, and show good matching with seismic reflection characteristics. Furthermore, the lateral variation characteristics of the instantaneous seismic phase in the interpretation results conform to geological laws. It is highly feasible and can be easily implemented by ordinary technical personnel in related fields, making it a valuable reference.

[0050] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for interpreting thin-layer seismic horizons, characterized in that, include: Synthetic seismic records were calibrated for wells in the study area based on well logging and seismic data. Based on the calibration results of the synthetic seismic records, the location of the top and bottom interfaces of the reservoir, the location of the top interface of the internal sub-layers of the reservoir, and the corresponding instantaneous seismic phase are determined. Within the range of the top and bottom interfaces of the reservoir, relatively stable seismic phase axes are interpreted to obtain relevant seismic properties; Based on drilling geological stratification data, the variation trend characteristics of formation thickness in all wells were statistically analyzed. Based on the aforementioned trend characteristics, statistical analysis is used to identify seismic attributes that reflect changes in stratigraphic structure and stratigraphic thickness as trend attributes. Using the calibration results and the instantaneous phase of the earthquake as reference standards, and the earthquake attributes as lateral trend constraint data, the interpretation of seismic horizons between wells and outside each well is determined.

2. The method according to claim 1, characterized in that, Also includes: The calibration results are adjusted for consistency by cross-validating the calibration results of adjacent wells.

3. The method according to claim 1, characterized in that, The trend attributes include: seismic reflection phase axis trend, seismic amplitude trend, and vertical stable phase axis formation thickness trend.

4. The method according to claim 1, characterized in that, The earthquake attributes include: seismic phase axis structural attributes, seismic phase axis amplitude attributes, and stratigraphic thickness attributes between longitudinally stable phase axes.

5. The method according to claim 4, characterized in that, The amplitude properties of the seismic in-phase axis include both frequency and phase attributes.

6. The method according to claim 1, characterized in that, The calibration of the synthetic seismic record includes: calibrating seismic horizons within the synthetic seismic record.

7. The method according to claim 1, characterized in that, The statistical analysis of the formation thickness variation trend of all wells includes: the lateral variation characteristics of the formation thickness of the corresponding reservoirs and inner layers of the reservoirs for all wells.

8. A thin-layer seismic horizon interpretation device, characterized in that, include: The calibration module is used to calibrate the synthetic seismic records of wells in the study area based on well logging data and seismic data, respectively. The determination module is used to determine the location of the top and bottom interfaces of the reservoir, the location of the top interface of the internal sub-layers of the reservoir, and the corresponding instantaneous phase of the seismic data based on the calibration results of the synthetic seismic record. The attribute module is used to interpret relatively stable seismic phase axes within the range of the top and bottom interfaces of the reservoir in order to obtain relevant seismic attributes; The statistics module is used to statistically analyze the variation trend characteristics of formation thickness in all wells based on the location of the top and bottom interfaces of the reservoir and the location of the top interface of the internal sub-layers of the reservoir. The analysis module, based on the aforementioned trend characteristics, statistically analyzes seismic attributes that can reflect changes in stratigraphic structure and stratigraphic thickness as trend attributes; as well as The interpretation module is used to determine the interpretation of seismic horizons between wells and outside each well, using the calibration results and the instantaneous phase of the earthquake as reference standards and the seismic attributes as lateral trend constraint data.

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