A method for identifying fire-driven high-temperature combustion

Abstract

This invention provides a method for identifying high-temperature combustion in fire-driven flooding. The method includes: identifying non-fire-driven production wells and effective fire-driven wells; analyzing the physicochemical properties of the produced water from the non-fire-driven production wells and the effective fire-driven wells; determining parameters for establishing discrimination charts for different development methods based on the physicochemical properties of the produced water; establishing discrimination charts for different development methods based on the parameters; and determining the criteria for identifying high-temperature combustion in fire-driven flooding based on the discrimination charts for different development methods. This invention establishes a discrimination criterion for high-temperature combustion in fire-driven flooding by analyzing parameters such as ion type and content, salinity, and hardness in the produced water from effective fire-driven wells and non-fire-driven production wells. Using the discrimination criteria of this invention avoids the high operational costs associated with discrimination through temperature monitoring and exhaust gas component analysis.

Description

Technical Field

[0001] This invention relates to the field of petroleum development technology, and more specifically, to a method for identifying fire-driven high-temperature combustion. Background Technology

[0002] Fire flooding is a thermal recovery method that generates heat within the oil reservoir, causing the crude oil to undergo a high-temperature oxidation reaction with injected air or oxygen, releasing a large amount of heat and gas. This displaces the unburned crude oil to the production well. This method eliminates heat loss along the wellbore and offers advantages such as high recovery rate, low cost, and wide applicability, making it an effective replacement technology after steam huff and puff in heavy oil reservoirs. Determining the underground combustion state during fire flooding is crucial for timely development and control measures, significantly impacting oilfield fire flooding development. Currently, commonly used methods for determining the combustion state in fire flooding primarily involve temperature monitoring and exhaust gas composition analysis. However, temperature monitoring is costly, hindering its large-scale application. Field production practice shows that the CO2 content in the exhaust gas is significantly affected by the carbonate mineral content and formation water properties in the reservoir, failing to accurately reflect the true combustion state during fire flooding. Summary of the Invention

[0003] The purpose of this invention is to provide a method for identifying fire-driven high-temperature combustion in order to improve the above-mentioned problems.

[0004] To achieve the above objectives, embodiments of this application provide a method for identifying fire-driven high-temperature combustion, the method comprising:

[0005] Identify non-fire-driven production wells and fire-driven effective wells;

[0006] The physicochemical properties of the produced water from the non-fire-driven production wells and the produced water from the effective fire-driven wells were analyzed.

[0007] The parameters used to establish a discrimination chart for different development methods are determined based on the physicochemical properties of the produced water;

[0008] Based on the parameters, establish the discrimination charts for different development methods, and determine the discrimination criteria for fire-driven high-temperature combustion based on the discrimination charts for different development methods.

[0009] Optionally, wells that are developed for steam injection can be designated as non-fire-driven production wells.

[0010] Optionally, the fire-driven production wells can be screened based on temperature monitoring data, total hydrocarbon chromatographic analysis results of the produced oil, or the produced tail gas to determine the effective fire-driven wells.

[0011] Optionally, based on the temperature monitoring data of the fire-drive production well, the fire-drive production well with an underground combustion temperature greater than 350°C is selected as the effective fire-drive well.

[0012] Optionally, based on the full hydrocarbon chromatographic analysis results of the produced oil from the fire-driven production well, the fire-driven production well where the crude oil has undergone high-temperature cracking is selected as the effective fire-driven well.

[0013] Optionally, based on the produced exhaust gas from the fire-drive production well, the fire-drive production well with a carbon dioxide content greater than 12% in the exhaust gas is selected as the effective fire-drive well.

[0014] Optionally, the parameters include the ion type and content of the produced water, alkalinity, mineralization, and hardness.

[0015] Optionally, the ions include potassium ions, sodium ions, magnesium ions, calcium ions, and chloride ions.

[0016] Optionally, the discrimination charts include discrimination charts for magnesium ions and potassium and sodium ions under different development methods, discrimination charts for calcium ions and potassium and sodium ions in the produced water under different development methods, discrimination charts for chloride ions and potassium and sodium ions in the produced water under different development methods, and charts showing the relationship between hardness and mineralization in the produced water under different development methods.

[0017] Optionally, the fire-driven high-temperature combustion discrimination criteria include six discrimination criteria, which are as follows: potassium and sodium ion content in the produced water is greater than 670 mg / L, calcium ion content in the produced water is greater than 80 mg / L, magnesium ion content in the produced water is greater than 36 mg / L, chloride ion content in the produced water is greater than 355 mg / L, mineralization of the produced water is greater than 2550 mg / L, and hardness of the produced water is greater than 240 mg / L.

[0018] Optionally, when performing fire-driven high-temperature discrimination, if any three of the six discrimination criteria are met, it is identified as a high-temperature combustion state.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. This invention establishes a high-temperature combustion discrimination standard for fire-driven wells by analyzing parameters such as ion type and content, salinity, and hardness in the produced water of effective fire-driven wells and non-fire-driven production wells. Using this discrimination standard avoids the high operational costs associated with methods such as temperature monitoring and exhaust gas component analysis.

[0021] 2. The present invention can determine the combustion state by the properties of the produced water. The operation is simple and convenient, which is conducive to the large-scale promotion and application of the method in this embodiment.

[0022] 3. The high-temperature oxidation during fire flooding causes feldspar minerals, clay minerals, carbonate minerals in the reservoir, and NaHCO3 in the formation water to undergo oxidative decomposition, releasing ions such as potassium, sodium, calcium, magnesium, and chloride. These ions are discharged with the produced fluid from the production well, leading to an increase in the ion content, mineralization, and hardness of the produced water. The higher the temperature, the greater the amount of mineral decomposition and the greater the amount of ions released. Therefore, based on the close relationship between produced water and combustion state, this invention analyzes the characteristics of produced fluids from non-fire flooding production wells and effective fire flooding wells to determine the relationship between high-temperature combustion during fire flooding and fluid properties. This method can improve the accuracy of high-temperature combustion identification.

[0023] 4. This invention can utilize the properties of produced water to determine the underground combustion state of fire-driven production wells, which is of great significance for evaluating the effectiveness of fire-driven development and formulating control strategies.

[0024] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The following are the magnesium ion and potassium / sodium ion discrimination diagrams for different development methods described in the embodiments of the present invention;

[0027] Figure 2 This is a discrimination chart for calcium and potassium / sodium ions in water produced by different development methods described in the embodiments of the present invention;

[0028] Figure 3 This is a discrimination chart for chloride and potassium / sodium ions in water produced by different development methods described in the embodiments of the present invention;

[0029] Figure 4 This is a graph showing the relationship between water hardness and mineralization produced by different development methods described in the embodiments of the present invention. Detailed Implementation

[0030] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0031] Example 1

[0032] This embodiment provides a method for identifying fire-driven high-temperature combustion, the method comprising:

[0033] Step 1: The oil wells that are developed by steam injection are designated as non-fire-driven production wells, and the fire-driven production wells with underground combustion temperatures greater than 350°C are designated as fire-driven effective wells.

[0034] Step 2: Analyze the physicochemical properties of the produced water from the non-fire-driven production well and the produced water from the fire-driven effective well. The physicochemical properties include ion type and content, alkalinity, mineralization, hardness, carbonate, and sulfate.

[0035] Step 3: Select the contents of potassium and sodium ions, magnesium ions, calcium ions, chloride ions, alkalinity, mineralization and hardness as parameters in the physicochemical properties.

[0036] Step 4: Establish discrimination charts for magnesium and potassium / sodium ions under different development methods, discrimination charts for calcium and potassium / sodium ions in the produced water under different development methods, discrimination charts for chloride and potassium / sodium ions in the produced water under different development methods, and charts showing the relationship between hardness and mineralization in the produced water under different development methods. Figure 1-4 As shown, Figure 1-4 The fire-drive well mentioned above is the effective fire-drive well in this embodiment. Figure 1-4 The steam injection well in this embodiment is the non-fire-driven production well.

[0037] Step 5: Determine the discrimination boundaries for different development methods based on the discrimination diagram, such as... Figure 1-4 As shown by the dashed lines, the horizontal and vertical coordinates corresponding to the dashed lines are used as the discrimination criteria; in this embodiment, through... Figure 1-4 The criteria for judging high-temperature combustion can be derived as follows: the potassium and sodium ion content in the produced water is greater than 670 mg / L, the calcium ion content in the produced water is greater than 80 mg / L, the magnesium ion content in the produced water is greater than 36 mg / L, the chloride ion content in the produced water is greater than 355 mg / L, the mineralization of the produced water is greater than 2550 mg / L, and the hardness of the produced water is greater than 240 mg / L.

[0038] When determining high-temperature combustion, the combustion state can be identified as high-temperature combustion if any three criteria are met. For example, if the potassium and sodium ion content in the produced water is greater than 670 mg / L, the calcium ion content is greater than 80 mg / L, and the magnesium ion content is greater than 36 mg / L, then the combustion state is identified as high-temperature combustion. If the chloride ion content in the produced water is greater than 355 mg / L, the mineralization is greater than 2550 mg / L, and the hardness is greater than 240 mg / L, then the combustion state is identified as high-temperature combustion. If the calcium ion content in the produced water is greater than 80 mg / L, the magnesium ion content is greater than 36 mg / L, and the chloride ion content is greater than 355 mg / L, then the combustion state is identified as high-temperature combustion.

[0039] In this embodiment, the oil wells developed by steam injection before the fire-drive development in block Du 66 were selected as non-fire-drive production wells; the oil wells developed by fire-drive in block Du 66 in 2008 and 2012 were selected as fire-drive effective wells.

[0040] This embodiment establishes a high-temperature combustion discrimination standard for fire-driven wells by analyzing parameters such as ion type and content, salinity, and hardness in the produced water from effective fire-driven wells and non-fire-driven production wells. Using this standard avoids the high operational costs associated with using methods such as temperature monitoring and exhaust gas component analysis.

[0041] This embodiment can determine the combustion state by the properties of the produced water. The operation is simple and convenient, which is conducive to the large-scale promotion and application of the method in this embodiment.

[0042] The high-temperature oxidation during fire flooding causes feldspar minerals, clay minerals, carbonate minerals in the reservoir, and NaHCO3 in the formation water to undergo oxidative decomposition, releasing ions such as potassium, sodium, calcium, magnesium, and chloride. These ions are discharged with the produced fluid from the production well, leading to an increase in the ion content, mineralization, and hardness of the produced water. The higher the temperature, the greater the amount of mineral decomposition and the greater the ion content released. Therefore, this embodiment, based on the close relationship between produced water and combustion state, analyzes the characteristics of produced fluids from non-fire flooding production wells and effective fire flooding wells to determine the relationship between high-temperature combustion during fire flooding and fluid properties. This method can improve the accuracy of high-temperature combustion identification.

[0043] Example 2

[0044] This embodiment provides a method for identifying fire-driven high-temperature combustion, the method comprising:

[0045] Step 1: Select oil wells that have undergone steam injection development as non-fire-driven production wells and select fire-driven production wells where crude oil has undergone high-temperature cracking as effective fire-driven wells.

[0046] Step 2: Analyze the physicochemical properties of the produced water from the non-fire-driven production well and the produced water from the fire-driven effective well. The physicochemical properties include ion type and content, alkalinity, mineralization, hardness, carbonate, and sulfate.

[0047] Step 3: Select the contents of potassium and sodium ions, magnesium ions, calcium ions, chloride ions, alkalinity, mineralization and hardness as parameters in the physicochemical properties.

[0048] Step 4: Establish graphs for distinguishing magnesium ions from potassium and sodium ions under different development methods, graphs for distinguishing calcium ions from potassium and sodium ions in water produced under different development methods, graphs for distinguishing chloride ions from potassium and sodium ions in water produced under different development methods, and graphs for the relationship between hardness and mineralization in water produced under different development methods.

[0049] Step 5: Based on the discrimination diagram, determine the discrimination boundaries for different development methods, and use the horizontal and vertical coordinates of the discrimination boundaries as the discrimination criteria.

[0050] Example 3

[0051] This embodiment provides a method for identifying fire-driven high-temperature combustion, the method comprising:

[0052] Step 1: Select oil wells that have undergone steam injection development as non-fire-driven production wells and select fire-driven production wells with a carbon dioxide content in the tail gas greater than 12% as fire-driven effective wells.

[0053] Step 2: Analyze the physicochemical properties of the produced water from the non-fire-driven production well and the produced water from the fire-driven effective well. The physicochemical properties include ion type and content, alkalinity, mineralization, hardness, carbonate, and sulfate.

[0054] Step 3: Select the contents of potassium and sodium ions, magnesium ions, calcium ions, chloride ions, alkalinity, mineralization and hardness as parameters in the physicochemical properties.

[0055] Step 4: Establish graphs for distinguishing magnesium ions from potassium and sodium ions under different development methods, graphs for distinguishing calcium ions from potassium and sodium ions in water produced under different development methods, graphs for distinguishing chloride ions from potassium and sodium ions in water produced under different development methods, and graphs for the relationship between hardness and mineralization in water produced under different development methods.

[0056] Step 5: Based on the discrimination diagram, determine the discrimination boundaries for different development methods, and use the horizontal and vertical coordinates of the discrimination boundaries as the discrimination criteria.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 discriminating high temperature combustion in a fire flood, characterized by, include: Identify non-fire-driven production wells and fire-driven effective wells; The physicochemical properties of the produced water from the non-fire-driven production wells and the produced water from the effective fire-driven wells were analyzed. The parameters used to establish a discrimination chart for different development methods are determined based on the physicochemical properties of the produced water; Based on the parameters, establish the discrimination charts for the different development methods, and determine the discrimination criteria for fire-driven high-temperature combustion based on the discrimination charts for the different development methods; Oil wells that are developed for steam injection will be classified as non-fire-driven production wells. Fire-driven production wells are screened based on temperature monitoring data, total hydrocarbon chromatographic analysis results of produced oil, or produced tail gas to determine the effective fire-driven wells. Based on the temperature monitoring data of the fire-drive production wells, the fire-drive production wells with an underground combustion temperature greater than 350℃ were selected as the effective fire-drive wells. Based on the full hydrocarbon chromatographic analysis results of the produced oil from the fire-driven production wells, the fire-driven production wells in which the crude oil underwent high-temperature cracking were selected as the effective fire-driven wells. Based on the produced tail gas from the fire-drive production well, the fire-drive production well with a carbon dioxide content greater than 12% in the tail gas is selected as the effective fire-drive well. The parameters include the ion type and content of the produced water, alkalinity, mineralization and hardness; The ions include potassium ions, sodium ions, magnesium ions, calcium ions, and chloride ions; The discrimination charts include discrimination charts for magnesium ions and potassium and sodium ions under different development methods, discrimination charts for calcium ions and potassium and sodium ions in the produced water under different development methods, discrimination charts for chloride ions and potassium and sodium ions in the produced water under different development methods, and charts showing the relationship between hardness and mineralization in the produced water under different development methods. The fire-driven high-temperature combustion discrimination criteria include six discrimination criteria, which are as follows: potassium and sodium ion content in the produced water is greater than 670 mg / L, calcium ion content in the produced water is greater than 80 mg / L, magnesium ion content in the produced water is greater than 36 mg / L, chloride ion content in the produced water is greater than 355 mg / L, mineralization of the produced water is greater than 2550 mg / L, and hardness of the produced water is greater than 240 mg / L. When performing fire-driven high-temperature discrimination, if any three of the six discrimination criteria are met, it is identified as a high-temperature combustion state.

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