Reef limestone diagenetic phase identification method based on acoustics and nuclear magnetic resonance parameters

Abstract

The invention discloses a reef limestone diagenetic phase identification method based on acoustics and nuclear magnetic resonance parameters, and relates to the technical field of reef limestone diagenetic phase identification. The reef limestone diagenetic phase identification method based on acoustics and nuclear magnetic resonance parameters comprises the following steps: S1, determining a research area, and collecting rock samples in the area; s2, carrying out basic observation on the rock sample obtained in the step S1, and recording measured data; s3, performing slice observation on the rock sample observed in the step S2, and recording measured data; s4, performing chemical analysis and physical test on the rock sample sliced in the step S3, and recording measured data; the lithogenous phase identification method with universality is established by using the acoustic parameters and the nuclear magnetic resonance parameters, the quality of the reservoir can be evaluated, meanwhile, the potential high-quality reservoir position can be predicted in an unknown area, the production potential of the reservoir can be evaluated, and a proper reservoir transformation scheme can be designed to improve the oil and gas yield.

Description

Technical Field

[0001] The invention relates to the technical field of reef limestone diagenetic phase identification, in particular to a reef limestone diagenetic phase identification method based on acoustic and nuclear magnetic resonance parameters. Background Art

[0002] Reef limestone is a special type of limestone, which is mainly composed of skeletal fragments of corals, algae and other marine organisms. It is usually formed in warm shallow sea environments. By identifying the diagenetic phases of different reef limestones, we can gain a deeper understanding of the various physical and chemical changes experienced during the formation of reef limestones, which helps scientists reconstruct ancient marine ecosystems and climate conditions. At the same time, reef limestones are often used as important oil and gas reservoirs. Diagenetic phase identification can be used to evaluate the quality of the reservoirs. Based on the understanding of known reef limestone diagenetic phases, potential high-quality reservoir locations can be predicted in unknown areas, which provides a great boost to oil and gas exploration. The existing diagenetic phase identification The method usually requires a large number of tests on the reef limestone samples to finally determine the diagenetic phase of the reef limestone samples. Although the results are very accurate, the whole process takes a very long time and consumes a lot of time, manpower, and equipment costs. For example, when using a diagenetic limestone-marlstone rhythm identification method disclosed in publication number CN116818752A to identify the diagenetic phase of the reef limestone, there is a need to conduct a large number of tests on the reef limestone samples. The whole process takes a very long time and consumes a lot of time, manpower, and equipment costs. Therefore, a reef limestone diagenetic phase identification method based on acoustic and nuclear magnetic resonance parameters is proposed. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a method for identifying the diagenetic phase of reef limestone based on acoustic and nuclear magnetic resonance parameters, which solves the problem that the current diagenetic phase identification method requires a large number of tests on the reef limestone samples to finally determine the diagenetic phase of the reef limestone samples. Although the results are very accurate, the whole process takes a very long time and consumes a lot of time, manpower and equipment costs.

[0004] To achieve the above objectives, the present invention is implemented by the following technical scheme: a method for identifying the diagenetic phase of reef limestone based on acoustic and nuclear magnetic resonance parameters, comprising the following steps: S1. Determine the research area and collect rock samples in the area; S2, performing basic observations on the rock samples obtained in step S1, and recording the measured data; S3, slice and observe the rock sample observed in step S2, and record the measured data; S4, performing chemical analysis and physical testing on the rock samples sliced ​​in step S3, and recording the measured data; S5, performing an acoustic wave test and a nuclear magnetic resonance test on the rock sample or rock matrix obtained in step S1; S6. Conduct diagenesis analysis based on the data obtained, and infer the diagenetic environment and process by analyzing the changes that occur during the diagenesis process; S7. Combine all data for comprehensive analysis and construct a diagenetic facies database of reef limestone.

[0005] Preferably, the rock samples collected in step S1 are in different layers and have different structural characteristics.

[0006] Preferably, the basic observations include: color, structure, texture, and recording of the types of fossils in the rock and their preservation status.

[0007] Preferably, the slice observation includes: mineral composition, crystal morphology, porosity, cement type, and the equipment used for the slice observation is a polarizing microscope or a scanning electron microscope.

[0008] Preferably, the chemical analysis includes: mineral phase, paleoenvironmental conditions, and trace element analysis. The equipment used to analyze the mineral phase is an X-ray diffractometer, the equipment used to analyze the paleoenvironmental conditions is an isotope mass spectrometer, and the equipment used to analyze the trace elements is an atomic absorption spectrometer.

[0009] Preferably, the physical test includes density, porosity, and permeability, and the changes occurring during the diagenesis process include physical changes and chemical changes. The physical changes include compaction, dissolution, and recrystallization, and the chemical changes include cementation and replacement.

[0010] Preferably, the method further comprises the following steps: S8, establishing a recognition model based on the diagenetic facies database in step S7; S9, taking reef limestone samples under different geological environments, and performing the test of step S5 on the reef limestone samples, and recording the measured data; S10, inputting the data obtained in step S9 into the recognition model established in step S8, and using the recognition model to compare and analyze the data obtained in step S9 with the rock characteristics in the diagenetic facies database; S11. Determine the diagenetic phase category of the reef limestone sample according to the comparative analysis result in step S10.

[0011] Preferably, the identification model established in step S8 includes classification criteria based on acoustic parameters and NMR parameters, and the classification criteria include: acoustic wave velocity, acoustic wave attenuation, T2 distribution, porosity, permeability, and fluid saturation; Low porosity and high sound velocity: indicates that the rock is dense, presumably due to compaction; High porosity / low sound velocity: indicates that the rock has more pores, which is presumably related to dissolution; Low attenuation coefficient: indicates that the rock has good pore connectivity, which is presumably related to dissolution and cementation; Narrow range of T2 distribution: indicates a relatively uniform distribution of pore sizes, presumably corresponding to a younger diagenetic phase; Wide range of T2 distribution: indicates uneven distribution of pore sizes, presumably corresponding to rocks that have undergone complex diagenesis; High permeability: presumably related to greater pore connectivity, usually corresponding to better reservoirs; Low permeability: presumably related to less pore connectivity, indicating that the rock has undergone compaction or other diagenetic processes; Low porosity, low acoustic velocity, low permeability: corresponds to the compacted diagenetic phase; High porosity, high acoustic velocity, high permeability: corresponds to dissolution or replacement diagenetic phases; High porosity, low attenuation coefficient, high permeability: corresponds to cemented diagenetic phase.

[0012] Preferably, the method further includes the following steps: S12, evaluating the accuracy of the recognition model by cross-validation, and adjusting the parameter range of the classification standard of the recognition model according to the validation result.

[0013] The present invention provides a method for identifying the diagenetic phase of reef limestone based on acoustic and nuclear magnetic resonance parameters. Compared with the prior art, it has the following beneficial effects: (1) This reef limestone diagenetic phase identification method based on acoustic and nuclear magnetic resonance parameters, by using acoustic parameters and nuclear magnetic resonance parameters to establish a universal diagenetic phase identification method, can help evaluate the quality of the reservoir, and at the same time predict the location of potential high-quality reservoirs in unknown areas, evaluate the production potential of the reservoir, and design appropriate reservoir transformation plans to increase oil and gas production. Through an in-depth understanding of the reservoir diagenetic phase, geological risks can be evaluated and economic feasibility analysis can be conducted, which can not only improve the success rate of oil and gas exploration and development, but also help optimize production processes, reduce costs, protect the environment, and provide a scientific basis for decision makers.

[0014] (2) This method of identifying the diagenetic phase of reef limestone based on acoustic and nuclear magnetic resonance parameters is helpful in assessing geological stability, selecting appropriate building materials and construction methods, and reducing engineering risks when constructing offshore platforms, bridges, tunnels and other projects. Through in-depth research on the diagenetic phase of reef limestone, it can provide a scientific basis for sustainable resource development and promote a balance between environmental protection and economic development. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the steps of the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 , the present invention provides the following technical solutions:

[0018] Embodiment 1

[0019] A method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters comprises the following steps: S1. Determine the research area and collect rock samples in the area; S2, performing basic observations on the rock samples obtained in step S1, and recording the measured data; S3, slice and observe the rock sample observed in step S2, and record the measured data; S4, performing chemical analysis and physical testing on the rock samples sliced ​​in step S3, and recording the measured data; S5, performing an acoustic wave test and a nuclear magnetic resonance test on the rock sample or rock matrix obtained in step S1; S6. Conduct diagenesis analysis based on the data obtained, and infer the diagenetic environment and process by analyzing the changes that occur during the diagenesis process; S7. Combine all data for comprehensive analysis and construct a diagenetic facies database of reef limestone.

[0020] The rock samples collected in step S1 are in different layers and have different structural characteristics.

[0021] Basic observations include: color, texture, structure, and recording the types of fossils in the rocks and their state of preservation.

[0022] Slice observations include: mineral composition, crystal morphology, porosity, and cement type. The equipment used for slice observations is a polarizing microscope or a scanning electron microscope.

[0023] Chemical analysis includes: mineral phase, paleoenvironmental conditions, and trace element analysis. The equipment used to analyze mineral phase is X-ray diffractometer, the equipment used to analyze paleoenvironmental conditions is isotope mass spectrometer, and the equipment used to analyze trace elements is atomic absorption spectrometer.

[0024] Physical tests include: density, porosity, and permeability. Changes that occur during diagenesis include physical changes and chemical changes. Physical changes include: compaction, dissolution, and recrystallization. Chemical changes include: cementation and replacement.

[0025] Embodiment 2: A method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters comprises the following steps: S1. Determine the research area and collect rock samples in the area; S2, performing basic observations on the rock samples obtained in step S1, and recording the measured data; S3, slice and observe the rock sample observed in step S2, and record the measured data; S4, performing chemical analysis and physical testing on the rock samples sliced ​​in step S3, and recording the measured data; S5, performing an acoustic wave test and a nuclear magnetic resonance test on the rock sample or rock matrix obtained in step S1; S6. Conduct diagenesis analysis based on the data obtained, and infer the diagenetic environment and process by analyzing the changes that occur during the diagenesis process; S7. Combine all data for comprehensive analysis and construct a diagenetic facies database of reef limestone; S8, establishing a recognition model based on the diagenetic facies database in step S7; S9, taking reef limestone samples under different geological environments, and performing the test of step S5 on the reef limestone samples, and recording the measured data; S10, inputting the data obtained in step S9 into the recognition model established in step S8, and using the recognition model to compare and analyze the data obtained in step S9 with the rock characteristics in the diagenetic facies database; S11, determining the diagenetic phase category of the reef limestone sample according to the comparative analysis result in step S10; S12. Use cross-validation to evaluate the accuracy of the recognition model and adjust the parameter range of the recognition model classification standard based on the validation results.

[0026] The rock samples collected in step S1 are in different layers and have different structural characteristics.

[0027] Basic observations include: color, texture, structure, and recording the types of fossils in the rocks and their state of preservation.

[0028] Slice observations include: mineral composition, crystal morphology, porosity, and cement type. The equipment used for slice observations is a polarizing microscope or a scanning electron microscope.

[0029] Chemical analysis includes: mineral phase, paleoenvironmental conditions, and trace element analysis. The equipment used to analyze mineral phase is X-ray diffractometer, the equipment used to analyze paleoenvironmental conditions is isotope mass spectrometer, and the equipment used to analyze trace elements is atomic absorption spectrometer.

[0030] Physical tests include density, porosity, and permeability. Changes that occur during diagenesis include physical changes and chemical changes. Physical changes include compaction, dissolution, and recrystallization. Chemical changes include cementation and replacement. The identification model established in step S8 includes classification standards based on acoustic parameters and NMR parameters. The classification standards include acoustic wave velocity, acoustic wave attenuation, T2 distribution, porosity, permeability, and fluid saturation. Low porosity and high sound velocity: indicates that the rock is dense, presumably due to compaction; High porosity / low sound velocity: indicates that the rock has more pores, which is presumably related to dissolution; Low attenuation coefficient: indicates that the rock has good pore connectivity, which is presumably related to dissolution and cementation; Narrow range T2 distribution: indicates a relatively uniform pore size distribution, presumably corresponding to a younger diagenetic phase; Wide range of T2 distribution: indicates uneven distribution of pore sizes, presumably corresponding to rocks that have undergone complex diagenesis; High permeability: presumably related to greater pore connectivity, usually corresponding to better reservoirs; Low permeability: presumably related to less pore connectivity, indicating that the rock has undergone compaction or other diagenetic processes; Low porosity, low acoustic velocity, low permeability: corresponds to the compacted diagenetic phase; High porosity, high acoustic velocity, high permeability: corresponds to dissolution or replacement diagenetic phases; High porosity, low attenuation coefficient, high permeability: corresponds to cemented diagenetic phase.

[0031] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0032] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters, characterized in that: The following steps are involved: S1. Determine the research area and collect rock samples in the area; S2, performing basic observations on the rock samples obtained in step S1, and recording the measured data; S3, slice and observe the rock sample observed in step S2, and record the measured data; S4, performing chemical analysis and physical testing on the rock samples sliced ​​in step S3, and recording the measured data; S5, performing an acoustic wave test and a nuclear magnetic resonance test on the rock sample or rock matrix obtained in step S1; S6. Conduct diagenesis analysis based on the data obtained, and infer the diagenetic environment and process by analyzing the changes that occur during the diagenesis process; S7. Combine all data for comprehensive analysis and construct a diagenetic facies database of reef limestone.

2. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 1, characterized in that: The rock samples collected in step S1 are in different layers and have different structural characteristics.

3. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 1, characterized in that: The basic observations include: color, structure, texture, and recording the types of fossils in the rocks and their preservation status.

4. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 1, characterized in that: The slice observation includes: mineral composition, crystal morphology, porosity, and cement type. The equipment used for the slice observation is a polarizing microscope or a scanning electron microscope.

5. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 1, characterized in that: The chemical analysis includes: mineral phase, paleoenvironmental conditions, and trace element analysis. The equipment used to analyze the mineral phase is an X-ray diffractometer, the equipment used to analyze the paleoenvironmental conditions is an isotope mass spectrometer, and the equipment used to analyze the trace elements is an atomic absorption spectrometer.

6. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 1, characterized in that: The physical tests include density, porosity, and permeability. The changes occurring during the diagenesis process include physical changes and chemical changes. The physical changes include compaction, dissolution, and recrystallization. The chemical changes include cementation and replacement.

7. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 1, characterized in that: The following steps are also included: S8, establishing a recognition model based on the diagenetic facies database in step S7; S9, taking reef limestone samples under different geological environments, and performing the test of step S5 on the reef limestone samples, and recording the measured data; S10, inputting the data obtained in step S9 into the recognition model established in step S8, and using the recognition model to compare and analyze the data obtained in step S9 with the rock characteristics in the diagenetic facies database; S11. Determine the diagenetic phase category of the reef limestone sample according to the comparative analysis result in step S10.

8. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 7, characterized in that: The identification model established in step S8 includes classification criteria based on acoustic parameters and NMR parameters, and the classification criteria include: acoustic wave velocity, acoustic wave attenuation, T2 distribution, porosity, permeability, and fluid saturation; Low porosity and high sound velocity: indicates that the rock is dense, presumably due to compaction; High porosity / low sound velocity: indicates that the rock has more pores, which is presumably related to dissolution; Low attenuation coefficient: indicates that the rock has good pore connectivity, which is presumably related to dissolution and cementation; Narrow range of T2 distribution: indicates a relatively uniform distribution of pore sizes, presumably corresponding to a younger diagenetic phase; Wide range of T2 distribution: indicates uneven distribution of pore sizes, presumably corresponding to rocks that have undergone complex diagenesis; High permeability: presumably related to greater pore connectivity, usually corresponding to better reservoirs; Low permeability: presumably related to less pore connectivity, indicating that the rock has undergone compaction or other diagenetic processes; Low porosity, low acoustic velocity, low permeability: corresponds to the compacted diagenetic phase; High porosity, high acoustic velocity, high permeability: corresponds to dissolution or replacement diagenetic phases; High porosity, low attenuation coefficient, high permeability: corresponds to cemented diagenetic phase.

9. The method for identifying diagenetic phases of reef limestone based on acoustic and nuclear magnetic resonance parameters according to claim 8, characterized in that: The following steps are also included: S12. Use cross-validation to evaluate the accuracy of the recognition model and adjust the parameter range of the recognition model classification standard based on the validation results.

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