Method for quantitatively characterizing and predicting chlorine content in deep stratum water

Abstract

The invention discloses a method for quantitatively characterizing and predicting the content of chlorine radicals in water in a deep stratum, and relates to the technical field of exploration and development of deep-ultra-deep tight sandstone gas reservoirs. Comprising the following steps: recovering burial history and thermal evolution history of a target stratum; quantitatively characterizing the water-rock reaction intensity; the method comprises the following steps: performing quantitative characterization and difference evaluation on the evolution process of the chlorine content in formation water, and recovering the burial history and thermal evolution history of a target layer. The method comprises the following steps: layering the formation by using a multi-data means; and recovering the denudation thickness and denudation time temperature by using a stratigraphic trend line method in combination with a stratigraphic structure movement background. According to the method, the evolution process of the chlorine content in the deep-ultra-deep stratum water can be accurately, rapidly and quantitatively characterized and evaluated by analyzing the stratum burial process, the thermal evolution history, the conventional geochemical data of the stratum water and other data. The analysis process is simple and easy to realize, the required data is less, and the method is a quick method for quantitatively analyzing the properties of the formation water in different periods.

Description

Technical Field

[0001] The invention relates to the technical field of exploration and development of deep-ultra-deep tight sandstone gas reservoirs, and in particular to a method for quantitatively characterizing and predicting the chloride content of deep formation water. Background Art

[0002] Deep-ultra-deep gas reservoirs are one of the important oil and gas exploration areas in my country now and in the future. However, with the deepening of the exploration and development process, most gas wells have begun to show the characteristics of water production, and the nature of the water production is very complex. There are certain differences in the salinity and chloride content of formation water produced by different gas wells. The chloride content of deep-ultra-deep formation water is significantly higher than that of shallow formation water. It is the main controlling factor of the mineralization content and the key indicator for judging the type of water produced by gas wells. Therefore, the difference in the nature of water production from different gas wells has greatly increased the difficulty for researchers to judge the type of formation water, which in turn makes gas reservoirs susceptible to water invasion. If the evolution process and causes of the chloride content of formation water can be quantitatively characterized, it will be of great significance for timely optimizing mining measures and improving oil and gas recovery.

[0003] Generally speaking, deep formation water in sedimentary basins mainly includes original sedimentary water, diagenetic water and atmospheric precipitation. The chloride content of formation water is mainly controlled by the degree of reaction between pore fluid and rock during sedimentation and burial (water-rock reaction) and the flow of pore fluid. Among them, water-rock reaction is a reaction process that all regions must experience during the evolution of formation water and is an important factor affecting the properties of formation water. However, the degree of reaction is still mainly described qualitatively. The flow of pore fluid can ensure the continuous progress of water-rock reaction, which is the main controlling factor of the intensity of water-rock reaction and the fundamental reason for the difference in chloride content of formation water in different well areas. Water-rock reaction is an ongoing diagenetic process, which is closely related to the burial depth and burial temperature of the formation. The difference in chloride content of formation water in different well areas reflects that it has experienced different water-rock reaction processes, that is, different sedimentation burial and paleo-geothermal evolution processes. Therefore, the burial process and temperature evolution history of the formation are the key to studying the intensity of water-rock reaction. If the evolution of chloride content in formation water in different well areas can be quantitatively characterized and evaluated, it will be of great significance for accurately determining the type of water produced by gas wells, optimizing production measures and improving oil and gas recovery. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a method for quantitatively characterizing and predicting the chloride content of deep formation water.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for quantitatively characterizing and predicting the chloride content of deep formation water comprises the following steps:

[0007] S1: Restore the burial history and thermal evolution history of the target layer;

[0008] S2: Quantitative characterization of water-rock reaction intensity;

[0009] S3: Quantitative characterization of the evolution of chloride content in formation water and evaluation of its differences.

[0010] Preferably, the step S1 comprises the following steps:

[0011] S11: Stratify the strata using multi-data methods;

[0012] S12: Combined with the tectonic movement background of the stratum, the erosion thickness and erosion time are restored using the stratigraphic trend line method;

[0013] S13: Restore the ancient geotemperature based on the correspondence between the geothermal gradient, measured temperature and vitrinite reflectance.

[0014] Preferably, in the step S11, the stratification is performed by means of logging lithology, logging curves, drilling coring and seismic exploration.

[0015] Preferably, the step S2 comprises the following steps:

[0016] S21: First, based on the burial history and thermal evolution history data, the burial time and temperature experienced by the target layer are divided into intervals with the temperature gradient as an interval;

[0017] S22: Then, each temperature interval is divided into evenly spaced intervals;

[0018] S23: finally accumulating the product of each small temperature interval and the elapsed time;

[0019] S24: Firstly, the burial depth of the target layer and the corresponding geological time are digitally read at equal intervals by using Matlab software to obtain the functional relationship between depth and time;

[0020] S25: then continue to digitally extract the burial depth and paleo-geothermal data at equal intervals to obtain the functional relationship between the burial depth and paleo-geothermal;

[0021] S26: Finally, the burial time and paleo-geothermal data are digitally extracted at equal intervals to obtain the functional relationship between the burial time and paleo-geothermal data.

[0022] Preferably: in the step S21, the temperature gradient is 10°C.

[0023] Preferably: in the step S22, each temperature interval is divided into n small intervals at intervals of 1°C.

[0024] Preferably: in the step S22, n=10.

[0025] The beneficial effects of the present invention are embodied in:

[0026] 1. The present invention can accurately and quickly quantitatively characterize and evaluate the evolution of chloride content in deep and ultra-deep formation water by analyzing the burial process of the formation, thermal evolution history, and conventional geochemical data of formation water. The analysis process is simple and easy to implement, and requires less data. It is a quick method that can quantitatively analyze the properties of formation water at different times. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0028] Figure 1 A flowchart of a method for quantitatively characterizing and predicting the chloride content of deep formation water proposed by the present invention;

[0029] Figure 2 A flow chart of the burial history and thermal evolution history of the target layer for a method of quantitatively characterizing and predicting the chloride content of deep formation water proposed by the present invention;

[0030] Figure 3 The invention discloses a flow chart of quantitative characterization of water-rock reaction intensity for a method of quantitatively characterizing and predicting chloride content in deep formation water. DETAILED DESCRIPTION

[0031] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0032] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0033] Embodiment 1:

[0034] A method for quantitatively characterizing and predicting the chloride content of deep formation water comprises the following steps:

[0035] S1: Restore the burial history and thermal evolution history of the target layer;

[0036] S2: Quantitative characterization of water-rock reaction intensity;

[0037] S3: Quantitative characterization of the evolution of chloride content in formation water and evaluation of its differences.

[0038] The step S1 comprises the following steps:

[0039] S11: Stratify the strata using multi-data methods;

[0040] S12: Combined with the tectonic movement background of the stratum, the erosion thickness and erosion time are restored using the stratigraphic trend line method;

[0041] S13: Restore the ancient geotemperature based on the correspondence between the geothermal gradient, measured temperature and vitrinite reflectance.

[0042] In the step S11, the stratification is performed by means of logging lithology, logging curves, drilling coring and seismic exploration.

[0043] Embodiment 2:

[0044] A method for quantitatively characterizing and predicting the chloride content of deep formation water comprises the following steps:

[0045] S1: Restore the burial history and thermal evolution history of the target layer;

[0046] S2: Quantitative characterization of water-rock reaction intensity;

[0047] S3: Quantitative characterization of the evolution of chloride content in formation water and evaluation of its differences.

[0048] The step S1 comprises the following steps:

[0049] S11: Stratify the strata using multi-data methods;

[0050] S12: Combined with the tectonic movement background of the stratum, the erosion thickness and erosion time are restored using the stratigraphic trend line method;

[0051] S13: Restore the ancient geotemperature based on the correspondence between the geothermal gradient, measured temperature and vitrinite reflectance.

[0052] In the step S11, the stratification is performed by means of logging lithology, logging curves, drilling coring and seismic exploration.

[0053] The step S2 comprises the following steps:

[0054] S21: First, based on the burial history and thermal evolution history data, the burial time and temperature experienced by the target layer are divided into intervals with the temperature gradient as an interval;

[0055] S22: Then, each temperature interval is divided into evenly spaced intervals;

[0056] S23: finally accumulating the product of each small temperature interval and the elapsed time;

[0057] S24: Firstly, the burial depth of the target layer and the corresponding geological time are digitally read at equal intervals by using Matlab software to obtain the functional relationship between depth and time;

[0058] S25: then continue to digitally extract the burial depth and paleo-geothermal data at equal intervals to obtain the functional relationship between the burial depth and paleo-geothermal;

[0059] S26: Finally, the burial time and paleo-geothermal data are digitally extracted at equal intervals to obtain the functional relationship between the burial time and paleo-geothermal data.

[0060] Embodiment 3:

[0061] A method for quantitatively characterizing and predicting the chloride content of deep formation water comprises the following steps:

[0062] S1: Restore the burial history and thermal evolution history of the target layer;

[0063] S2: Quantitative characterization of water-rock reaction intensity;

[0064] S3: Quantitative characterization of the evolution of chloride content in formation water and evaluation of its differences.

[0065] The step S1 comprises the following steps:

[0066] S11: Stratify the strata using multi-data methods;

[0067] S12: Combined with the tectonic movement background of the stratum, the erosion thickness and erosion time are restored using the stratigraphic trend line method;

[0068] S13: Restore the ancient geotemperature based on the correspondence between the geothermal gradient, measured temperature and vitrinite reflectance.

[0069] In the step S11, the stratification is performed by means of logging lithology, logging curves, drilling coring and seismic exploration.

[0070] The step S2 comprises the following steps:

[0071] S21: First, based on the burial history and thermal evolution history data, the burial time and temperature experienced by the target layer are divided into intervals with the temperature gradient as an interval;

[0072] S22: Then, each temperature interval is divided into evenly spaced intervals;

[0073] S23: finally accumulating the product of each small temperature interval and the elapsed time;

[0074] S24: Firstly, the burial depth of the target layer and the corresponding geological time are digitally read at equal intervals by using Matlab software to obtain the functional relationship between depth and time;

[0075] S25: then continue to digitally extract the burial depth and paleo-geothermal data at equal intervals to obtain the functional relationship between the burial depth and paleo-geothermal;

[0076] S26: Finally, the burial time and paleo-geothermal data are digitally extracted at equal intervals to obtain the functional relationship between the burial time and paleo-geothermal data.

[0077] In the step S21, the temperature gradient is 10°C.

[0078] Embodiment 4:

[0079] A method for quantitatively characterizing and predicting the chloride content of deep formation water comprises the following steps:

[0080] S1: Restore the burial history and thermal evolution history of the target layer;

[0081] S2: Quantitative characterization of water-rock reaction intensity;

[0082] S3: Quantitative characterization of the evolution of chloride content in formation water and evaluation of its differences.

[0083] The step S1 comprises the following steps:

[0084] S11: Stratify the strata using multi-data methods;

[0085] S12: Combined with the tectonic movement background of the stratum, the erosion thickness and erosion time are restored using the stratigraphic trend line method;

[0086] S13: Restore the ancient geotemperature based on the correspondence between the geothermal gradient, measured temperature and vitrinite reflectance.

[0087] In the step S11, the stratification is performed by means of logging lithology, logging curves, drilling coring and seismic exploration.

[0088] The step S2 comprises the following steps:

[0089] S21: First, based on the burial history and thermal evolution history data, the burial time and temperature experienced by the target layer are divided into intervals with the temperature gradient as an interval;

[0090] S22: Then, each temperature interval is divided into evenly spaced intervals;

[0091] S23: finally accumulating the product of each small temperature interval and the elapsed time;

[0092] S24: Firstly, the burial depth of the target layer and the corresponding geological time are digitally read at equal intervals by using Matlab software to obtain the functional relationship between depth and time;

[0093] S25: then continue to digitally extract the burial depth and paleo-geothermal data at equal intervals to obtain the functional relationship between the burial depth and paleo-geothermal;

[0094] S26: Finally, the burial time and paleo-geothermal data are digitally extracted at equal intervals to obtain the functional relationship between the burial time and paleo-geothermal data.

[0095] In the step S21, the temperature gradient is 10°C.

[0096] In the step S22, each temperature interval is divided into n small intervals at intervals of 1°C.

[0097] Embodiment 5:

[0098] A method for quantitatively characterizing and predicting the chloride content of deep formation water comprises the following steps:

[0099] S1: Restore the burial history and thermal evolution history of the target layer;

[0100] S2: Quantitative characterization of water-rock reaction intensity;

[0101] S3: Quantitative characterization of the evolution of chloride content in formation water and evaluation of its differences.

[0102] The step S1 comprises the following steps:

[0103] S11: Stratify the strata using multi-data methods;

[0104] S12: Combined with the tectonic movement background of the stratum, the erosion thickness and erosion time are restored using the stratigraphic trend line method;

[0105] S13: Restore the ancient geotemperature based on the correspondence between the geothermal gradient, measured temperature and vitrinite reflectance.

[0106] In the step S11, the stratification is performed by means of logging lithology, logging curves, drilling coring and seismic exploration.

[0107] The step S2 comprises the following steps:

[0108] S21: First, based on the burial history and thermal evolution history data, the burial time and temperature experienced by the target layer are divided into intervals with the temperature gradient as an interval;

[0109] S22: Then, each temperature interval is divided into evenly spaced intervals;

[0110] S23: finally accumulating the product of each small temperature interval and the elapsed time;

[0111] S24: Firstly, the burial depth of the target layer and the corresponding geological time are digitally read at equal intervals by using Matlab software to obtain the functional relationship between depth and time;

[0112] S25: then continue to digitally extract the burial depth and paleo-geothermal data at equal intervals to obtain the functional relationship between the burial depth and paleo-geothermal;

[0113] S26: Finally, the burial time and paleo-geothermal data are digitally extracted at equal intervals to obtain the functional relationship between the burial time and paleo-geothermal data.

[0114] In the step S21, the temperature gradient is 10°C.

[0115] In the step S22, each temperature interval is divided into n small intervals at intervals of 1°C.

[0116] In the step S22, n=10.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for quantitatively characterizing and predicting the chloride content of deep formation water, characterized in that: The following steps are involved: S1: Restore the burial history and thermal evolution history of the target layer; S2: Quantitative characterization of water-rock reaction intensity; S3: Quantitative characterization of the evolution of chloride content in formation water and evaluation of its differences.

2. The method for quantitatively characterizing and predicting the chloride content of deep formation water according to claim 1, characterized in that: The step S1 comprises the following steps: S11: Stratify the strata using multi-data methods; S12: Combined with the tectonic movement background of the stratum, the erosion thickness and erosion time are restored using the stratigraphic trend line method; S13: Restore the ancient geotemperature based on the correspondence between the geothermal gradient, measured temperature and vitrinite reflectance.

3. The method for quantitatively characterizing and predicting the chloride content of deep formation water according to claim 2, characterized in that: In the step S11, the stratification is performed by means of logging lithology, logging curves, drilling coring and seismic exploration.

4. The method for quantitatively characterizing and predicting the chloride content of deep formation water according to claim 1, characterized in that: The step S2 comprises the following steps: S21: First, based on the burial history and thermal evolution history data, the burial time and temperature experienced by the target layer are divided into intervals with the temperature gradient as an interval; S22: Then, each temperature interval is divided into evenly spaced intervals; S23: finally accumulating the product of each small temperature interval and the elapsed time; S24: Firstly, the burial depth of the target layer and the corresponding geological time are digitally read at equal intervals by using Matlab software to obtain the functional relationship between depth and time; S25: then continue to digitally extract the burial depth and paleo-geothermal data at equal intervals to obtain the functional relationship between the burial depth and paleo-geothermal; S26: Finally, the burial time and paleo-geothermal data are digitally extracted at equal intervals to obtain the functional relationship between the burial time and paleo-geothermal data.

5. The method for quantitatively characterizing and predicting the chloride content of deep formation water according to claim 4, characterized in that: In the step S21, the temperature gradient is 10°C.

6. The method for quantitatively characterizing and predicting the chloride content of deep formation water according to claim 5, characterized in that: In the step S22, each temperature interval is divided into n small intervals at intervals of 1°C.

7. The method for quantitatively characterizing and predicting the chloride content of deep formation water according to claim 6, characterized in that: In the step S22, n=10.

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