Method and device for predicting distribution of secondary dissolution pores in carbonate rocks

Abstract

This invention discloses a method and apparatus for predicting the distribution of secondary dissolution pores in carbonate rocks. The method includes: selecting carbonate rock samples from the target layer in the study area; setting experimental conditions based on the reservoir type and fluid type of the carbonate rock samples; analyzing the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of the carbonate rock samples based on the set experimental conditions, and generating analytical results; determining the controlling factors affecting the dissolution rate of the carbonate rock samples based on the analytical results; and predicting the distribution of secondary dissolution pores based on the controlling factors. This invention can effectively predict the distribution of secondary dissolution pores in carbonate rocks, providing a basis for evaluating the development potential of dissolution pores in carbonate rocks.

Description

Technical Field

[0001] This invention relates to the field of geological exploration and oil and gas exploration technology, and in particular to a method and apparatus for predicting the distribution of secondary solution pores in carbonate rocks. Background Technology

[0002] This section is intended to provide background or context for the embodiments of the invention set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0003] The formation of pores in deep carbonate rocks is based on two approaches: "forward modeling" and "inverse modeling." "Forward modeling" involves simulating carbonate rock dissolution and precipitation to approximate the actual geological background, reproducing the main controlling factors of pore formation and maintenance during geological history, and revealing the changes in pore throat structure and the distribution patterns of burial dissolution cavities. "Inverse modeling," on the other hand, uses elemental and isotopic geochemical analysis of sedimentary / diagenetic minerals to determine the age, temperature, pressure, and fluid properties of the formation, thus inferring the mechanisms of pore development and maintenance in carbonate rocks during geological history.

[0004] Traditional methods primarily rely on inversion to infer the burial, filling, and porosity reduction processes of pre-existing pores, leading to significant limitations in the study of the controlling factors and distribution patterns of buried dissolution pores. Traditional forward modeling methods can only meet the needs of simulation experiments for studying the distribution patterns of buried dissolution pores in shallow to medium-depth carbonate rocks that approximate the actual geological background. Currently, there is no well-established and reliable method for predicting the distribution of secondary dissolution pores in deep carbonate rocks. Summary of the Invention

[0005] This invention provides a method for predicting the distribution of secondary dissolution pores in carbonate rocks, which effectively predicts the distribution of secondary dissolution pores in carbonate rocks and provides a basis for evaluating the development potential of dissolution pores in carbonate rocks. The method includes:

[0006] Carbonate rock samples were selected from the target layer in the study area, and experimental conditions were set according to the reservoir type and fluid type of the carbonate rock samples.

[0007] Based on the established experimental conditions, the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples were analyzed sequentially, and the analysis results were generated.

[0008] Based on the analysis results, the controlling factors affecting the dissolution rate of carbonate rock samples were determined;

[0009] Predict the distribution of secondary solution pores based on controlling factors.

[0010] This invention also provides a device for predicting the distribution of secondary dissolution pores in carbonate rocks, which effectively predicts the distribution of secondary dissolution pores in carbonate rocks and provides a basis for evaluating the development potential of dissolution pores in carbonate rocks. The device includes:

[0011] The experimental conditions setting module is used to select carbonate rock samples from the target layer in the study area and set experimental conditions according to the reservoir type and fluid type of the carbonate rock samples.

[0012] The analysis results generation module is used to analyze the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples based on the set experimental conditions, and generate analysis results.

[0013] The control factor determination module is used to determine the control factors affecting the dissolution rate of carbonate rock samples based on the analysis results.

[0014] The solution pore distribution prediction module is used to predict the distribution of secondary solution pores based on control factors.

[0015] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-mentioned method for predicting the distribution of secondary dissolution pores in carbonate rocks.

[0016] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for predicting the distribution of secondary dissolution pores in carbonate rocks.

[0017] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-mentioned method for predicting the distribution of secondary dissolution pores in carbonate rocks.

[0018] In this embodiment of the invention, carbonate rock samples are selected from the target layer in the study area, and experimental conditions are set according to the reservoir type and fluid type of the carbonate rock samples. Based on the set experimental conditions, the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples are analyzed sequentially, and analytical results are generated. Based on the analytical results, the controlling factors affecting the dissolution rate of carbonate rock samples are determined. Based on the controlling factors, the distribution of secondary dissolution pores is predicted. In the above process, this embodiment of the invention obtains the controlling factors of the dissolution rate of carbonate rock samples through analysis, and effectively predicts the distribution of secondary dissolution pores in carbonate rocks based on the controlling factors, providing a basis for evaluating the development potential of dissolution pores in carbonate rocks. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0020] Figure 1 This is a flowchart of a method for predicting the distribution of secondary dissolution pores in carbonate rocks in an embodiment of the present invention;

[0021] Figure 2 This is a flowchart illustrating the setting of experimental conditions in an embodiment of the present invention;

[0022] Figure 3 This is a flowchart illustrating the effect of fluid concentration on the dissolution rate of carbonate rock samples in an embodiment of the present invention;

[0023] Figure 4 This is a flowchart illustrating the influence of lithology and physical properties on the dissolution rate of carbonate rock samples in an embodiment of the present invention;

[0024] Figure 5 This is a flowchart for determining control factors in an embodiment of the present invention;

[0025] Figure 6 These are the simulation results of the effect of mineral type on dissolution rate in the embodiments of the present invention;

[0026] Figure 7 These are simulation results of the effect of fluid type and concentration on the dissolution rate in embodiments of the present invention;

[0027] Figure 8 The results are simulation experiments showing the influence of lithology and physical properties on the dissolution rate in embodiments of the present invention.

[0028] Figure 9 This is a schematic diagram of a device for predicting the distribution of secondary dissolution pores in carbonate rocks in an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0030] Figure 1 This is a flowchart of a method for predicting the distribution of secondary dissolution pores in carbonate rocks according to an embodiment of the present invention. The method includes:

[0031] Step 101: Select carbonate rock samples from the target layer in the study area, and set experimental conditions according to the reservoir type and fluid type of the carbonate rock samples.

[0032] Step 102: Based on the set experimental conditions, analyze the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples in sequence, and generate analysis results;

[0033] Step 103: Based on the analysis results, determine the controlling factors affecting the dissolution rate of carbonate rock samples;

[0034] Step 104: Predict the distribution of secondary solution pores based on control factors.

[0035] Each step is explained in detail below.

[0036] In step 101, carbonate rock samples are selected from the target layer in the study area, and experimental conditions are set according to the reservoir type and fluid type of the carbonate rock samples.

[0037] In a specific embodiment, sample selection and experimental condition setting include:

[0038] Step 11: Determine the research object, target layer, and burial history;

[0039] Step 12: Select sample types that are representative of reservoir evolution;

[0040] Step 13: Determine the temperature and pressure evolution history experienced by the target layer;

[0041] Step 14: Determine the type of acidic fluid experienced during the evolution of the target layer.

[0042] According to a specific embodiment of the present invention, step 11, determining the research object, the target layer, and the burial history, includes:

[0043] The research object and target layer are determined based on the basin, region, and stratigraphic position of the target carbonate rock;

[0044] Based on previous research findings on the research object and target layer, we can obtain the tectonic burial evolution history.

[0045] According to a specific embodiment of the present invention, step 12, determining the sample type representative of reservoir evolution, includes:

[0046] For the main reservoir section of the target layer, samples with different physical properties were selected to determine the lithological type, rock structure and diagenetic sequence;

[0047] Lithological types include dolomite, limestone, calcareous dolomite, and dolomitic limestone;

[0048] Rock structures include granular structure, mudstone structure, granular mudstone structure, micritic structure, stromatolite structure, clotted structure, foamy layer structure, reef framework structure, and granular structure.

[0049] Diagenetic sequence, including determining the types of quasi-syngenetic diagenesis and the types of diagenesis during the burial period;

[0050] Quasi-syngenetic diagenetic processes include: texture-selective dissolution, seawater cementation, atmospheric water cementation, dolomitization, and compaction.

[0051] Types of diagenesis during the burial period include: burial dissolution, burial infilling, burial-hydrothermal dolomitization, pressure solution, and fracturing.

[0052] Diagenetic sequence, including establishing the chronological relationship of various diagenetic processes based on the cutting relationships of the products of various diagenetic processes;

[0053] Furthermore, based on the diagenetic sequence and pore development characteristics, the reservoir pore evolution process was established;

[0054] The type of experimental simulation sample is determined based on the evolution process of reservoir porosity.

[0055] According to a specific embodiment of the present invention, step 13, determining the temperature and pressure evolution history experienced by the target layer, includes:

[0056] Based on the tectonic burial evolution history, the burial depth, temperature, and pressure of the main tectonic periods experienced by the target layer are determined.

[0057] According to a specific embodiment of the present invention, step 14, determining the type of acidic fluid experienced during the evolution of the target layer, includes:

[0058] Based on the burial process and diagenetic characteristics of the target layer, determine the type of diagenetic fluid experienced by the target layer;

[0059] Diagenetic fluid types include atmospheric water, seawater, formation fluids, organic acids, and hydrothermal fluids;

[0060] Among them, acidic fluids include: CO2-rich atmospheric water fluids during the quasi-syngenetic exposure period, organic acids related to the maturation of underlying source rocks during the burial period, and hydrothermal fluids represented by CO2-rich fluids during the burial period.

[0061] Figure 2 This is a flowchart illustrating the setting of experimental conditions in an embodiment of the present invention. In one embodiment, the experimental conditions are set according to the reservoir type and fluid type of the carbonate rock sample, including:

[0062] Step 201: Determine the temperature and pressure points and the depth range of buried dissolution cavities for the simulation experiment based on the reservoir type of the carbonate rock sample.

[0063] Step 202: Determine the solution type, fluid flow rate parameters, and concentration parameters for the simulation experiment based on the fluid type of the carbonate rock sample.

[0064] Step 203: The determined temperature and pressure points, the depth range of buried dissolution cavities, the solution type, the fluid flow rate parameters, and the concentration parameters are used as experimental conditions.

[0065] In step 102, based on the set experimental conditions, the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples are analyzed in sequence, and analysis results are generated.

[0066] In one embodiment, based on set experimental conditions, the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples are analyzed sequentially, generating analytical results, including:

[0067] Plunger rock samples of porous dolomite and porous limestone with the same physical properties were selected. Under the condition of gradually increasing temperature and pressure, they were subjected to the same concentration of acetic acid and CO2-rich solution fluid dissolution. The dissolution rate of each plunger rock sample at different temperature and pressure, different mineral types and different solution types was determined.

[0068] Based on the trend of dissolution rate, the influence of mineral type on the dissolution rate of plunger rock samples is analyzed, and the analysis results are generated.

[0069] In a specific embodiment, the implementation of the simulation experiment includes:

[0070] Step 21: Set up a simulation experiment plan based on reservoir type and fluid type;

[0071] Step 22: Conduct simulation experiments on the effect of carbonate mineral type on dissolution rate;

[0072] Step 23: Conduct simulation experiments on the effects of fluid type and concentration on the dissolution rate of carbonate minerals;

[0073] Step 24: Conduct simulation experiments on the effects of lithology and physical properties on the dissolution rate of carbonate minerals.

[0074] According to a specific embodiment of the present invention, step 21, setting a simulation experiment scheme based on reservoir type and fluid type, includes:

[0075] The experimental simulation sample type was determined based on the reservoir porosity evolution process, and the sample permeability was required to reach 0.1 mD.

[0076] Based on the burial history and the temperature and pressure evolution process experienced by the target layer, the temperature and pressure points and variation ranges of the simulation experiment are determined;

[0077] Based on the type of acidic fluid experienced by the target layer, determine the solution type and parameters for the simulation experiment.

[0078] The temperature and pressure points and their range of variation in the burial experiment were determined based on the burial depth and temperature and pressure points during the key tectonic period, taking into account the occurrence and stages of dissolution in the reservoir; the solution type in the burial experiment included the partial pressure of CO2 in near-surface CO2-containing atmospheric water, the concentration of organic acids during the burial period, and the partial pressure of CO2 in CO2-rich fluids during the burial period; the parameters of the burial experiment included the determination of fluid flow rate and sampling analysis points, as well as the measurement of the concentration of dissolution product ions.

[0079] According to a specific embodiment of the present invention, step 22, the simulation experiment on the effect of carbonate mineral type on dissolution rate, includes:

[0080] Porous dolomite and porous limestone plunger samples with similar physical properties were subjected to acetic acid and CO2-rich fluid dissolution, respectively.

[0081] Simulation experiments were conducted on the dissolution rate of calcite by acetic acid under gradually increasing temperature and pressure conditions; the dissolution rate of dolomite by acetic acid under gradually increasing temperature and pressure conditions; the dissolution rate of calcite by CO2-rich fluid under gradually increasing temperature and pressure conditions; and the dissolution rate of dolomite by CO2-rich fluid under gradually increasing temperature and pressure conditions. During the temperature and pressure increases, the temperature interval did not exceed 20°C, and the pressure did not exceed 15 MPa. For the selected porous dolomite and porous limestone plunger samples, the porosity and permeability parameters were kept close to ensure similar specific surface areas for dissolution.

[0082] According to a specific embodiment of the present invention, step 23, the simulation experiment on the effect of fluid type and concentration on the dissolution rate of carbonate minerals, includes:

[0083] Porous dolomite and porous limestone plunger samples with similar physical properties were selected for erosion simulation using different concentrations of acetic acid and CO2 fluids.

[0084] Specifically, this includes acetic acid solutions of 2 ml / l and 3.5 ml / l and saturated CO2 solutions of 2 ml / l and 3.5 ml / l; conducting simulation experiments on the dissolution of dolomite and limestone with acidic fluids of different concentrations under conditions of gradually increasing temperature and pressure; and ensuring that the porosity and permeability parameters of the selected porous dolomite and porous limestone plunger samples are similar in order to ensure that the specific surface area of ​​the dissolution is similar.

[0085] Figure 3 This is a flowchart illustrating the effect of fluid concentration on the dissolution rate of carbonate rock samples in an embodiment of the present invention. In one embodiment, based on set experimental conditions, the relationship between fluid concentration and the dissolution rate of carbonate rock samples is analyzed, and analysis results are generated, including:

[0086] Step 301: Select plunger rock samples of porous dolomite and porous limestone with the same physical properties. Under the condition of gradually increasing temperature and pressure, conduct fluid dissolution with acetic acid and CO2-rich solutions of different concentrations to determine the dissolution rate of each plunger rock sample at different temperature and pressure points, different solution types, and different solution concentrations.

[0087] Step 302: Based on the trend of dissolution rate, analyze the effect of fluid concentration on the dissolution rate of carbonate rock samples and generate analysis results.

[0088] According to a specific embodiment of the present invention, step 24, the simulation experiment on the influence of lithology and physical properties on the dissolution rate of carbonate minerals, includes:

[0089] Dolomite and limestone plunger samples with different physical properties were selected for dissolution simulation using saturated solutions of acetic acid and CO2 of the same concentration. Specifically, 2 ml / L acetic acid solution and saturated CO2 solution were selected for simulation. The porosity and permeability parameters of the selected porous dolomite and porous limestone plunger samples differed greatly, as did the specific surface area of ​​the dissolution.

[0090] Figure 4 This is a flowchart illustrating the influence of lithology and physical properties on the dissolution rate of carbonate rock samples in an embodiment of the present invention. In one embodiment, based on set experimental conditions, the relationship between lithology, physical properties, and the dissolution rate of carbonate rock samples is analyzed, and analysis results are generated, including:

[0091] Step 401: Select plunger rock samples of porous dolomite and porous limestone with different physical properties. During the dissolution process of each plunger rock sample with the same concentration of acetic acid and CO2-rich solution, determine the dissolution rate of each plunger rock sample under different solution types, different lithologies and physical properties.

[0092] Step 402: Based on the changing trend of dissolution rate, analyze the influence of lithology and physical properties on the dissolution rate of carbonate rock samples and generate analysis results.

[0093] In step 103, based on the analysis results, the controlling factors affecting the dissolution rate of carbonate rock samples are determined.

[0094] In a specific embodiment, the interpretation of the simulation experiment results includes:

[0095] Step 31, Interpretation of simulation results on the influence of carbonate rock mineral type on dissolution rate;

[0096] Step 32, Interpretation of simulation results on the effect of fluid type and concentration on the dissolution rate of carbonate minerals;

[0097] Step 33: Interpretation of simulation experiment results on the influence of lithology and physical properties on the dissolution rate of carbonate minerals.

[0098] According to a specific embodiment of the present invention, in step 31, the interpretation of the simulation experiment results on the influence of carbonate rock mineral type on the dissolution rate includes:

[0099] Create a cross-plot of the measured ion concentrations in the reaction fluid at each temperature and pressure point with the corresponding temperature and pressure conditions, sample type, and type of dissolving fluid;

[0100] The study analyzed the ion concentrations of different carbonate mineral types in different solutions at different temperature and pressure points, i.e., the dissolution rates; and analyzed the changing trends of ion concentrations of different carbonate mineral types in different solutions during temperature and pressure changes.

[0101] According to a specific embodiment of the present invention, in step 32, the interpretation of the simulation experimental results on the effect of fluid type and concentration on the dissolution rate of carbonate minerals includes:

[0102] Create a cross-plot of the measured ion concentrations in the reaction fluid at each temperature and pressure point with the corresponding temperature and pressure conditions, sample type, and type of dissolving fluid;

[0103] The study analyzed the ion concentrations of different carbonate mineral types in different solutions at different temperature and pressure points, which is the magnitude of the dissolution rate; and analyzed the changing trends of ion concentrations of different carbonate mineral types in different solutions during temperature and pressure changes.

[0104] According to a specific embodiment of the present invention, in step 33, the interpretation of the simulation experiment results on the influence of lithology and physical properties on the dissolution rate of carbonate minerals includes:

[0105] Create a cross-plot of the measured ion concentrations in the reaction fluid at each temperature and pressure point with the corresponding temperature and pressure conditions, sample type, and type of dissolving fluid;

[0106] The study analyzed the ion concentrations of different carbonate mineral types in different solutions at different temperature and pressure points, which is the magnitude of the dissolution rate; and analyzed the changing trends of ion concentrations of different carbonate mineral types in different solutions during temperature and pressure changes.

[0107] In step 104, the distribution of secondary dissolution pores is predicted based on control factors.

[0108] Figure 5 This is a flowchart illustrating the determination of control factors in an embodiment of the present invention. In one embodiment, based on the analysis results, the control factors affecting the dissolution rate of carbonate rock samples are determined, including:

[0109] Step 501: Based on the analysis results, determine the correlation between mineral type, fluid type, fluid concentration, lithology, physical properties and dissolution rate of carbonate rock samples;

[0110] Step 502: Determine the controlling factors affecting the dissolution rate of carbonate rock samples based on the correlation.

[0111] Based on specific embodiments, a simulation experiment was conducted to study the development and control of buried dissolution cavities, clarifying the main controlling factors and distribution patterns of dissolution cavities in deep carbonate rocks. The specific operation steps are as follows:

[0112] 1. Sample selection and experimental condition setting

[0113] The samples were collected from Sinian-Cambrian carbonate rocks in the Sichuan Basin. The temperature and pressure data of the simulation experiment were obtained from the reconstruction of the actual sample temperature and pressure field, and were (80℃, 48MPa), (110℃, 66MPa), (130℃, 78MPa), (150℃, 90MPa), (170℃, 102MPa), (190℃, 114MPa), (210℃, 126MPa), and (230℃, 138MPa). The sample characteristics and experimental conditions are shown in Table 1.

[0114] Table 1. Characteristics of the simulated experimental samples and experimental conditions

[0115]

[0116]

[0117] 2. Implementation and Results of the Simulation Experiment

[0118] Considering the temperature at which hydrocarbons mature into organic acids, the instability of acetic acid (an organic acid) under high temperature and pressure conditions (pyrolysis), and the dominant role of deep-to-ultra-deep CO2-saturated solutions (inorganic acids), the reaction solution for the middle and shallow layers uses both acetic acid and CO2-saturated solutions, while the reaction solution for the deep-to-ultra-deep layers uses only CO2-saturated solutions. The fluid composition and content of the reaction solution are obtained through real-time online monitoring, which is highly efficient and has low error. Within a unit of time, the ion concentration is directly proportional to the dissolution rate of carbonate minerals, reflecting the development potential of buried dissolution cavities.

[0119] (1) Simulation experiment on the influence of carbonate mineral type on dissolution rate

[0120] For the selected porous dolomite and porous limestone plunger samples, the porosity and permeability parameters were kept close to ensure similar specific surface areas for dissolution. Simulation experiments were conducted at eight temperature and pressure points according to the experimental conditions and operational requirements set in Table 1.

[0121] Figure 6 These are simulation results of the effect of mineral type on dissolution rate in embodiments of the present invention. Figure 6As shown, in shallow to medium-depth layers, the dissolution rate of calcite by acetic acid is much greater than that of dolomite. With increasing temperature and pressure, the dissolution rates of both calcite and dolomite show an increasing trend. In deep to ultra-deep layers, the dissolution rate of dolomite by CO2-saturated solution increases rapidly with increasing temperature and pressure, and is significantly greater than that of calcite. This indicates that the development potential of buried dissolution cavities in deep to ultra-deep dolomite is greater than that in limestone.

[0122] (2) Simulation experiment on the effect of fluid type and concentration on the dissolution rate of carbonate minerals

[0123] For the selected porous dolomite and porous limestone plunger samples, the porosity and permeability parameters were kept close to ensure similar specific surface areas for dissolution. Simulation experiments were conducted at eight temperature and pressure points according to the experimental conditions and operational requirements set in Table 1.

[0124] Figure 7 These are simulation results of the effect of fluid type and concentration on the dissolution rate in embodiments of the present invention. Figure 7 As shown, in shallow to medium-depth layers, the dissolution rate of carbonate minerals increases with increasing temperature and pressure. Acetic acid has a higher dissolution rate for carbonate minerals than a CO2-saturated solution, and the higher the concentration of acetic acid, the greater the dissolution rate. In deep to ultra-deep layers, the dissolution rate of dolomite by a CO2-saturated solution increases rapidly and is significantly greater than that of calcite. This conclusion is consistent with simulation experiments on the influence of carbonate mineral type on the dissolution rate. This indicates that CO2-saturated solutions can also form buried dissolution cavities in deep to ultra-deep layers through dissolution. The higher the concentration of acidic fluid, the greater the potential for the development of buried dissolution cavities. Different types of acidic fluids result in different rock dissolution rates.

[0125] (3) Simulation experiment on the influence of lithology and physical properties on the dissolution rate of carbonate minerals

[0126] The selected porous dolomite and porous limestone plunger samples showed significant differences in porosity and permeability parameters, as well as in the specific surface area of ​​dissolution. Simulation experiments were conducted at eight temperature and pressure points according to the experimental conditions and operational requirements set in Table 1.

[0127] Figure 8 These are simulation experimental results illustrating the influence of lithology and physical properties on the dissolution rate in embodiments of the present invention. Figure 8 As shown, in the shallow and medium layers, the solubility (ion concentration) of dolomite and limestone by acetic acid solution and saturated CO2 solution both increase with increasing temperature and pressure, with dolomite showing a greater solubility (ion concentration) than limestone. In the deep to ultra-deep layers, the solubility (ion concentration) of dolomite by saturated CO2 solution increases rapidly with increasing temperature and pressure, and is greater than that of limestone. This indicates that in addition to temperature and pressure, mineral type, and the type and concentration of acidic fluids controlling the amount of dissolution (ion concentration), porosity and permeability conditions also play an important controlling role in the amount of dissolution (ion concentration).

[0128] 3. Comprehensive interpretation of simulation experiment results

[0129] As can be seen from the above experimental process, the dissolution rate of calcite and dolomite minerals is an inherent property of mineral crystals and will not change due to changes in external conditions. In the first two simulation experiments (1) and (2), the porosity and permeability parameters are similar, and the specific surface area of ​​dissolution is similar. At this time, the amount of dissolution (ion concentration) can represent the magnitude of the dissolution rate. However, in the third simulation experiment (3), the porosity and permeability and specific surface area of ​​dissolution of dolomite are much larger than those of limestone. At this time, the amount of dissolution (ion concentration) cannot represent the magnitude of the dissolution rate. The fact that the dissolution rate of limestone is greater than that of dolomite remains unchanged. The dissolution amount (ion concentration) of limestone is less than that of dolomite, which is not caused by the dissolution rate, but by the difference in the specific surface area of ​​dissolution. As long as the specific surface area of ​​dissolution is large enough (porosity and permeability are good enough), even minerals with very small dissolution rates can produce a large amount of dissolution or form many buried dissolution cavities. This demonstrates that initial porosity and permeability control ion concentration and the potential for secondary dissolution pore development, not only the dissolution rate but even more so than mineral composition (dissolution rate). This well explains why buried dissolution pores are mainly distributed along pre-existing high-permeability layers or fractures, indicating a hereditary nature.

[0130] This invention also provides a device for predicting the distribution of secondary dissolution pores in carbonate rocks, as described in the following embodiments. Since the principle behind this device is similar to the method for predicting the distribution of secondary dissolution pores in carbonate rocks, its implementation can be referenced from the method for predicting the distribution of secondary dissolution pores in carbonate rocks; repeated details will not be elaborated further.

[0131] Figure 9 This is a schematic diagram of a device for predicting the distribution of secondary dissolution pores in carbonate rocks according to an embodiment of the present invention. The device includes:

[0132] The experimental condition setting module 901 is used to select carbonate rock samples from the target layer in the study area and set experimental conditions according to the reservoir type and fluid type of the carbonate rock samples.

[0133] The analysis result generation module 902 is used to analyze the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples based on the set experimental conditions, and generate analysis results.

[0134] The control factor determination module 903 is used to determine the control factors affecting the dissolution rate of carbonate rock samples based on the analysis results.

[0135] The solution pore distribution prediction module 904 is used to predict the distribution of secondary solution pores based on control factors.

[0136] In one embodiment, the experimental condition setting module 901 is specifically used for:

[0137] Based on the reservoir type of the carbonate rock sample, the temperature and pressure points and the depth range of buried dissolution cavities in the simulation experiment were determined.

[0138] Based on the fluid type of the carbonate rock sample, determine the solution type, fluid flow rate parameters, and concentration parameters for the simulation experiment;

[0139] The determined temperature and pressure points, the depth range of buried dissolution cavities, the solution type, fluid flow rate parameters, and concentration parameters were used as experimental conditions.

[0140] In one embodiment, the analysis result generation module 902 is specifically used for:

[0141] Plunger rock samples of porous dolomite and porous limestone with the same physical properties were selected. Under the condition of gradually increasing temperature and pressure, they were subjected to the same concentration of acetic acid and CO2-rich solution fluid dissolution. The dissolution rate of each plunger rock sample at different temperature and pressure, different mineral types and different solution types was determined.

[0142] Based on the trend of dissolution rate, the influence of mineral type on the dissolution rate of plunger rock samples is analyzed, and the analysis results are generated.

[0143] In one embodiment, the analysis result generation module 902 is specifically used for:

[0144] Plunger rock samples of porous dolomite and porous limestone with the same physical properties were selected. Under the condition of gradually increasing temperature and pressure, they were subjected to fluid dissolution with acetic acid and CO2-rich solutions of different concentrations. The dissolution rate of each plunger rock sample at different temperature and pressure points, different solution types, and different solution concentrations was determined.

[0145] Based on the changing trend of dissolution rate, the influence of fluid concentration on the dissolution rate of carbonate rock samples was analyzed, and the analysis results were generated.

[0146] In one embodiment, the analysis result generation module 902 is specifically used for:

[0147] Plunger rock samples of porous dolomite and porous limestone with different physical properties were selected. During the dissolution process of each plunger rock sample under different solution types, different lithologies and physical properties, the dissolution rate of each plunger rock sample was determined during the process of dissolution by acetic acid and CO2-rich solutions of the same concentration.

[0148] Based on the changing trend of dissolution rate, the influence of lithology and physical properties on the dissolution rate of carbonate rock samples is analyzed, and analytical results are generated.

[0149] In one embodiment, the control factor determination module 903 is specifically used for:

[0150] Based on the analysis results, the correlation between mineral type, fluid type, fluid concentration, lithology, physical properties and dissolution rate of carbonate rock samples was determined;

[0151] The controlling factors affecting the dissolution rate of carbonate rock samples were determined based on the correlation.

[0152] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-mentioned method for predicting the distribution of secondary dissolution pores in carbonate rocks.

[0153] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for predicting the distribution of secondary dissolution pores in carbonate rocks.

[0154] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-mentioned method for predicting the distribution of secondary dissolution pores in carbonate rocks.

[0155] In this embodiment of the invention, carbonate rock samples are selected from the target layer in the study area, and experimental conditions are set according to the reservoir type and fluid type of the carbonate rock samples. Based on the set experimental conditions, the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples are analyzed sequentially, and analytical results are generated. Based on the analytical results, the controlling factors affecting the dissolution rate of carbonate rock samples are determined. Based on the controlling factors, the distribution of secondary dissolution pores is predicted. In the above process, this embodiment of the invention obtains the controlling factors of the dissolution rate of carbonate rock samples through analysis, and effectively predicts the distribution of secondary dissolution pores in carbonate rocks based on the controlling factors, providing a basis for evaluating the development potential of dissolution pores in carbonate rocks.

[0156] 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, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0157] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0158] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0159] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0160] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for predicting the distribution of secondary solution pores in carbonate rocks, characterized in that, include: Carbonate rock samples were selected from the target layer in the study area, and experimental conditions were set according to the reservoir type and fluid type of the carbonate rock samples. Based on the established experimental conditions, the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples were analyzed sequentially, and the analysis results were generated. Based on the analysis results, the controlling factors affecting the dissolution rate of carbonate rock samples were determined; Predict the distribution of secondary solution pores based on controlling factors.

2. The method as described in claim 1, characterized in that, Based on the reservoir type and fluid type of the carbonate rock samples, experimental conditions were set, including: Based on the reservoir type of the carbonate rock sample, the temperature and pressure points and the depth range of buried dissolution cavities in the simulation experiment were determined. Based on the fluid type of the carbonate rock sample, determine the solution type, fluid flow rate parameters, and concentration parameters for the simulation experiment; The determined temperature and pressure points, the depth range of buried dissolution cavities, the solution type, fluid flow rate parameters, and concentration parameters were used as experimental conditions.

3. The method as described in claim 1, characterized in that, Based on the established experimental conditions, the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples were analyzed sequentially, and the analysis results were generated, including: Plunger rock samples of porous dolomite and porous limestone with the same physical properties were selected. Under the condition of gradually increasing temperature and pressure, they were subjected to the same concentration of acetic acid and CO2-rich solution fluid dissolution. The dissolution rate of each plunger rock sample at different temperature and pressure, different mineral types and different solution types was determined. Based on the trend of dissolution rate, the influence of mineral type on the dissolution rate of plunger rock samples is analyzed, and the analysis results are generated.

4. The method as described in claim 1, characterized in that, Based on the established experimental conditions, the relationship between fluid concentration and the dissolution rate of carbonate rock samples was analyzed, and the analytical results were generated, including: Plunger rock samples of porous dolomite and porous limestone with the same physical properties were selected. Under the condition of gradually increasing temperature and pressure, they were subjected to fluid dissolution with acetic acid and CO2-rich solutions of different concentrations. The dissolution rate of each plunger rock sample at different temperature and pressure points, different solution types, and different solution concentrations was determined. Based on the changing trend of dissolution rate, the influence of fluid concentration on the dissolution rate of carbonate rock samples was analyzed, and the analysis results were generated.

5. The method as described in claim 1, characterized in that, Based on the established experimental conditions, the relationship between lithology, physical properties, and dissolution rate of carbonate rock samples was analyzed, and the analytical results were generated, including: Plunger rock samples of porous dolomite and porous limestone with different physical properties were selected. During the dissolution process of each plunger rock sample under different solution types, different lithologies and physical properties, the dissolution rate of each plunger rock sample was determined during the process of dissolution by acetic acid and CO2-rich solutions of the same concentration. Based on the changing trend of dissolution rate, the influence of lithology and physical properties on the dissolution rate of carbonate rock samples is analyzed, and analytical results are generated.

6. The method as described in claim 1, characterized in that, Based on the analysis results, the controlling factors affecting the dissolution rate of carbonate rock samples were identified, including: Based on the analysis results, the correlation between mineral type, fluid type, fluid concentration, lithology, physical properties and dissolution rate of carbonate rock samples was determined; The controlling factors affecting the dissolution rate of carbonate rock samples were determined based on the correlation.

7. A device for predicting the distribution of secondary solution pores in carbonate rocks, characterized in that, include: The experimental condition setting module is used to select carbonate rock samples from the target layer in the study area and set experimental conditions according to the reservoir type and fluid type of the carbonate rock samples. The analysis results generation module is used to analyze the effects of mineral type, fluid type, fluid concentration, lithology, and physical properties on the dissolution rate of carbonate rock samples based on the set experimental conditions, and generate analysis results. The control factor determination module is used to determine the control factors affecting the dissolution rate of carbonate rock samples based on the analysis results. The solution pore distribution prediction module is used to predict the distribution of secondary solution pores based on control factors.

8. The apparatus as claimed in claim 7, characterized in that, The experimental conditions setting module is specifically used for: Based on the reservoir type of the carbonate rock sample, the temperature and pressure points and the depth range of buried dissolution cavities in the simulation experiment were determined. Based on the fluid type of the carbonate rock sample, determine the solution type, fluid flow rate parameters, and concentration parameters for the simulation experiment; The determined temperature and pressure points, the depth range of buried dissolution cavities, the solution type, fluid flow rate parameters, and concentration parameters were used as experimental conditions.

9. The apparatus as claimed in claim 7, characterized in that, The analysis results generation module is specifically used for: Plunger rock samples of porous dolomite and porous limestone with the same physical properties were selected. Under the condition of gradually increasing temperature and pressure, they were subjected to the same concentration of acetic acid and CO2-rich solution fluid dissolution. The dissolution rate of each plunger rock sample at different temperature and pressure, different mineral types and different solution types was determined. Based on the trend of dissolution rate, the influence of mineral type on the dissolution rate of plunger rock samples is analyzed, and the analysis results are generated.

10. The apparatus as claimed in claim 7, characterized in that, The analysis results generation module is specifically used for: Plunger rock samples of porous dolomite and porous limestone with the same physical properties were selected. Under the condition of gradually increasing temperature and pressure, they were subjected to fluid dissolution with acetic acid and CO2-rich solutions of different concentrations. The dissolution rate of each plunger rock sample at different temperature and pressure points, different solution types, and different solution concentrations was determined. Based on the changing trend of dissolution rate, the influence of fluid concentration on the dissolution rate of carbonate rock samples was analyzed, and the analysis results were generated.

11. The apparatus as claimed in claim 7, characterized in that, The analysis results generation module is specifically used for: Plunger rock samples of porous dolomite and porous limestone with different physical properties were selected. During the dissolution process of each plunger rock sample under different solution types, different lithologies and physical properties, the dissolution rate of each plunger rock sample was determined during the process of dissolution by acetic acid and CO2-rich solutions of the same concentration. Based on the changing trend of dissolution rate, the influence of lithology and physical properties on the dissolution rate of carbonate rock samples is analyzed, and analytical results are generated.

12. The apparatus as claimed in claim 7, characterized in that, The control factor determination module is specifically used for: Based on the analysis results, the correlation between mineral type, fluid type, fluid concentration, lithology, physical properties and dissolution rate of carbonate rock samples was determined; The controlling factors affecting the dissolution rate of carbonate rock samples were determined based on the correlation.

13. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 6.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method of any one of claims 1 to 6.

15. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method of any one of claims 1 to 6.

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