A method for determining the uniform temperature of a brine inclusion

Abstract

The application provides a method for measuring the homogeneous temperature of a brine inclusion, comprising the following steps: placing a sample to be measured on a cooling and heating table, adjusting the cooling and heating table and a microscope, and preparing for temperature increase; starting temperature increase, pausing temperature increase after each temperature increase step T, and determining whether the sample to be measured reaches homogeneity by using a check package, wherein the check package determines whether the sample to be measured reaches homogeneity according to whether bubbles in the sample to be measured completely disappear; if the sample to be measured does not reach homogeneity, returning to the previous step and continuing temperature increase by one temperature increase step; and if the sample to be measured reaches homogeneity, recording the homogeneous temperature T of the sample to be measured h , wherein the homogeneous temperature T h indicates that the brine inclusion is homogeneous within the range of (T h -T, T h ]. The application does not need to observe instantaneous homogeneity, can simultaneously observe fluid inclusions in multiple fields of view, reduces the dependence on naked eye observation in the process of measuring the homogeneous temperature, and can improve the reproducibility and accuracy of data.

Description

Technical Field

[0001] This invention relates to the field of geochemistry, and more particularly to a method for determining the homogenization temperature of brine inclusions. Background Technology

[0002] Fluid inclusions trapped within minerals during their growth process preserve various geochemical information about the geological environment at that time (such as temperature, pressure, and composition). Therefore, through qualitative or quantitative analysis of ancient fluids within fluid inclusions, we can obtain various data and information to further interpret various geological processes in the Earth's crust and mantle. Fluid inclusion analysis has been widely applied in geosciences such as ore deposit geology, petroleum exploration, and structural geology, and is currently one of the most active areas of research in Earth sciences.

[0003] Fluid inclusion thermometry is the most convenient and widely used non-destructive method to directly obtain the temperature, pressure, and salinity of fluid inclusions at the time of capture. The principle of the homogenization method for determining homogenization temperature is as follows: A two-phase gas-liquid inclusion (captured as a single phase) is selected. Using a hot-cold stage, the gas-liquid two-phase mixture is heated to a certain temperature, at which point it transforms into a single phase, restoring the phase state at the time of inclusion formation (single phase). The instantaneous temperature at which this transformation occurs is the homogenization temperature of the inclusion.

[0004] Patent CN109580702B provides a detection method using a package temperature measurement system. The system uses a host computer to detect the temperature of a hot and cold platform. If the temperature of the platform is between 15-25℃, the temperature is continuously increased. Motion detection is performed using background subtraction or frame difference methods based on the feedback video to determine whether the package is maintaining motion. If the package is not maintaining motion, it is determined to have disappeared, and the heating is stopped. The temperature fed back by the hot and cold platforms at the time of stopping is recorded. Although this method uses an image acquisition system to identify phase changes within the package, it does not actually change the way the phase transition process (the homogenization process from two phases to one phase) is identified. Under different observation conditions, different people will still identify different homogenization temperatures, failing to solve the problem of reproducibility of homogenization temperature data.

[0005] Patent CN109580702B provides a method for determining the homogenization temperature and freezing point temperature of fluid inclusions. The method involves placing a sample of the fluid inclusion to be tested in the sample chamber of a calibrated microscope's heating and cooling stage, initiating heating while pausing to observe the phase changes of the fluid inclusions. When the bubbles in the fluid inclusions become significantly smaller and are nearing disappearance, the heating rate is reduced until the fluid inclusions reach a homogenous phase; this temperature is the measured homogenization temperature. Heating continues, is paused, and then cooled. When bubbles are observed to reappear in the fluid inclusions, this temperature is recorded as the recurrence temperature. The measured homogenization temperature is compared with the recurrence temperature; if the measured homogenization temperature is greater than the recurrence temperature, the measured homogenization temperature is considered the actual homogenization temperature of the fluid inclusions. This method does not solve the problem of the accuracy of homogenization temperature data. For example, when the bubbles in the fluid inclusions become significantly smaller and are about to disappear, the heating rate is reduced until the fluid inclusions reach a homogenous phase. The temperature at this point is the measured homogenization temperature of the fluid inclusions. It still determines whether a homogenous phase has been reached during the heating process. The heating rate may be very slow, but the homogenization temperature identified by different people under different observation conditions will still be different. Although the "homogenization temperature" and "reproduced temperature" will be compared later, the accuracy of the "homogenization temperature" identification is still not guaranteed. In addition, the comparison between "homogenization temperature" and "reproduced temperature" cannot, as the patent applicant stated, "make the measurement results closer to the true temperature and effectively avoid errors caused by objective factors or human factors in the temperature measurement experiment."

[0006] Therefore, there is an urgent need for a more accurate and reproducible method for determining the homogenization temperature of brine inclusions. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention proposes a method for determining the homogeneity temperature of brine inclusions.

[0008] This invention proposes a method for determining the homogenization temperature of brine inclusions, comprising the following steps:

[0009] Step 1: At room temperature, the sample to be tested is heated by a heating step T using a hot and cold stage. A test kit is used to determine whether the sample has reached homogeneity. The test kit determines whether the sample has reached homogeneity based on whether the bubbles in the sample have completely disappeared.

[0010] Step 2: If uniformity is not achieved, return to Step 1 and continue heating by one heating step;

[0011] Step 3: If homogeneity is achieved, record the bubble disappearance temperature T of the sample. miss =T room +nT,

[0012] Among them, T room The room temperature is 1, and n is an integer greater than or equal to 1.

[0013] The uniformity temperature T h In (T) room +(n-1)T,T room Within the range of +nT].

[0014] The homogenization temperature of the brine inclusions is determined by the fluid inclusion homogenization method. The principle is as follows: Select a gas-liquid two-phase inclusion (an inclusion that is a single phase when captured), and use a hot-cold stage to heat it to a certain temperature. When the gas-liquid two-phase inclusion transforms into a single phase, the phase state at which the inclusion was formed (single phase) is restored. The instantaneous temperature at which the phase is restored is the homogenization temperature of the inclusion.

[0015] As a specific embodiment of the present invention, in step 1, the complete disappearance of bubbles means that the sample to be tested is at T room No bubbles can be observed at +nT temperature, and the temperature drops to T. room Even at +(n-1)T, bubbles cannot be observed; where T room The temperature is room temperature, and n is an integer greater than or equal to 1; the sample is at T room The temperature at which bubbles cannot be observed at +nT is the critical temperature at which bubbles disappear.

[0016] As a specific embodiment of the present invention, step 1, in which the inspection package is used to determine whether the sample to be tested has reached homogeneity, further includes: if the sample to be tested is internally homogeneous in T... room If bubbles can be observed at +mT, the sample to be tested is not homogeneous and the temperature needs to be increased further. m is an integer greater than or equal to 1.

[0017] In a specific embodiment of the present invention, in step 1, the heating step size T is 1-10℃ / min.

[0018] As a specific embodiment of the present invention, in step 1, after heating by one heating step T, the test sample is used to determine whether it has reached uniformity, and then the test sample is subjected to heat preservation treatment.

[0019] In a specific embodiment of the present invention, step S3 further includes determining the homogenization temperature T. h In (T) room +(n-1)T,T room After reaching the range of +nT], with T room +(n-1)T is the initial temperature. Using T′ as the heating step size, repeat steps 1-3 to obtain the homogenization temperature T. h In (T) room +(n-1)T+(n'-1)T',T roomWithin the range of +nT+(n'T'), where T'<T;

[0020] Preferably, the above operation is repeated until a uniform temperature value approximating the point value is obtained.

[0021] As a specific embodiment of the present invention, during the measurement process, such as Figure 2 As shown, in T room At temperature +(n+1)T, no obvious bubbles can be observed initially; the temperature is then lowered to T. room +nT, at this temperature no bubbles were observed to reappear, indicating that the brine inclusions were at T room It has already achieved homogeneity at temperature +(n+1)T, T room +(n+1)T is the homogenization temperature of the brine inclusion, indicating that the brine inclusion is homogenized at (T room +nT,T room The value is uniform within the range of +(n+1)T].

[0022] As a specific embodiment of the present invention, during the measurement process, such as Figure 3 As shown, in T room At temperature +(n+1)T, no obvious bubbles can be observed initially; the temperature is then lowered to T. room +nT, at this temperature, bubbles reappear, indicating that the brine inclusions are not homogeneous and have returned to the temperature T before cooling. room +(n+1)T, then continue heating by one heating step to reach T. room +(n+2)T, at this temperature no bubbles were observed, and the temperature was lowered to T. room +nT, at this temperature no bubbles were observed to reappear, indicating that the brine inclusions were at T room It has already achieved homogeneity at temperature +(n+2)T, T room +(n+2)T is the homogenization temperature of the brine inclusion, indicating that the brine inclusion is homogenized at (T room +(n+1)T,T room The value is uniform within the range of [+(n+2)T].

[0023] As a specific embodiment of the present invention, during the measurement process, such as Figure 4 As shown, in T room At temperature +(n+1)T, no obvious bubbles can be observed initially; the temperature is then lowered to T. room +nT, at this temperature, bubbles reappear, indicating that the brine inclusions are not homogeneous and have returned to the temperature T before cooling. room +(n+1)T, then continue heating by one heating step to reach T. room +(n+2)T, at this temperature no bubbles were observed, and the temperature was lowered to T. room+nT, at this temperature, bubbles can still be observed to reappear, indicating that the brine inclusions are still not homogeneous, returning to the temperature T before cooling. room +(n+2)T, then continue heating by one heating step to reach T. room +(n+3)T, at this temperature no bubbles were observed, and the temperature was lowered to T. room +nT, at this temperature no bubbles were observed to reappear, indicating that the brine inclusions were at T room It has already achieved homogeneity at temperature +(n+3)T, T room +(n+3)T is the homogenization temperature of the brine inclusion, indicating that the brine inclusion is homogenized at (T room +(n+2)T,T room The value is uniform within the range of [+(n+3)T].

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The measurement method of the present invention does not require observation of the "instantaneous" homogeneity phenomenon, but adopts the method of heating step size to constrain the temperature range in which the "homogeneity phenomenon" occurs. According to different temperature step sizes, homogeneity temperatures that meet different geological requirements can be obtained. Furthermore, after obtaining a homogeneity temperature with a larger step size, a homogeneity temperature with a smaller step size can be obtained quickly.

[0026] 2. The uniform temperature data obtained in the embodiments of the present invention has high repeatability and high consistency obtained through repeated testing, thereby improving data reproducibility and accuracy;

[0027] 3. The measurement method of the present invention does not require observation of "instantaneous uniformity phenomenon", that is, the observer does not need to keep staring at a few inclusions for observation. The observer only needs to make a judgment at a specific observation point. This method can free the observer's eyes and observe inclusions in multiple fields of view at the same time. The number of inclusions that can be observed in the same heating process is greater than that of conventional methods. Attached Figure Description

[0028] Figure 1 This is a schematic flowchart of the method for determining the homogeneity temperature of brine inclusions according to the present invention.

[0029] Figure 2 This is a schematic diagram of the uniform temperature measurement results in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the uniform temperature measurement results in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the uniform temperature measurement results in an embodiment of the present invention. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0033] In various embodiments of the present invention, a ZEISS polarizing microscope Axio Scope A1 pol type and a Linkam hot and cold stage TMHSE600 type are used.

[0034] Example 1

[0035] This embodiment provides a method for determining the homogenization temperature of brine inclusions, applied to a brine inclusion A, with specific details as follows:

[0036] Step 1: Place the sample A to be tested in the hot and cold stage, T room =20℃, adjust the hot and cold stages and microscope, and prepare for heating;

[0037] Step 2: Begin heating, selecting a heating step size of 10℃. Pause heating after each heating step T = 10℃ and use a check bag to determine if the sample has achieved homogeneity. The check bag determines homogeneity based on whether air bubbles in the sample have completely disappeared. If homogeneity is not achieved, return to the previous step and continue heating for one more heating step. If homogeneity is achieved, record the homogenization temperature T of the sample. h The homogenization temperature T h This indicates that the saltwater inclusions are in (T) h -T,T h Uniform within the range.

[0038] Step 3: During the measurement process, at T room At temperature +(n+1)T (n=5, then 80℃), no obvious bubbles can be observed for the first time. The temperature is then lowered to T. room +nT(70℃), at this temperature no bubbles were observed to reappear, indicating that the brine inclusions were at T room The brine inclusions have reached homogeneity at a temperature of +(n+1)T (80℃). 80℃ is the homogeneity temperature of the brine inclusions, indicating that the brine inclusions are homogeneous within the range of (70, 80).

[0039] The homogenization temperature of the brine inclusion A obtained in Example 1 was 80°C.

[0040] Example 2

[0041] This embodiment provides a method for determining the homogenization temperature of brine inclusions, applied to a brine inclusion B, with specific details as follows:

[0042] Step 1: Place the sample A to be tested in the hot and cold stage, T room =20℃, adjust the hot and cold stages and microscope, and prepare for heating;

[0043] Step 2: Begin heating, increasing the temperature by one step T = 5℃, then pause heating and observe whether the bubbles in the sample have completely disappeared to determine if the sample has reached homogeneity. If homogeneity has not been achieved, return to the previous step and continue heating by one step. If homogeneity has been achieved, record the homogenization temperature T of the sample. h The homogenization temperature T h This indicates that the saltwater inclusions are in (T) h -T,T h Uniform within the range.

[0044] Step 3: During the measurement process, at T room At temperature +(n+1)T (n=11, then 80℃), no obvious bubbles can be observed for the first time. The temperature is then lowered to T. room +nT(75℃), at this temperature, bubbles reappear, indicating that the brine inclusions are not homogeneous and have returned to the temperature T before cooling. room +(n+1)T(80℃), then continue heating in one heating step to reach T. room +(n+2)T(85℃), no bubbles were observed at this temperature, and the temperature was lowered to T. room +nT(75℃), at this temperature no bubbles were observed to reappear, indicating that the brine inclusions were at T room The brine inclusions have reached homogeneity at a temperature of +(n+2)T (85℃). 85℃ is the homogeneity temperature of the brine inclusions, indicating that the brine inclusions are homogeneous within the range of (80, 85).

[0045] The homogenization temperature of the brine inclusion B obtained in Example 2 was 85°C.

[0046] Example 3

[0047] This embodiment provides a method for determining the homogenization temperature of brine inclusions, applied to a brine inclusion C, with specific details as follows:

[0048] Step 1: Place the sample A to be tested in the hot and cold stage, T room =20℃, adjust the hot and cold stages and microscope, and prepare for heating;

[0049] Step 2: Begin heating, pausing the heating process after each heating step T = 1℃. Use a test kit to determine if the sample has achieved homogeneity. The test kit determines homogeneity based on whether air bubbles in the sample have completely disappeared. If homogeneity is not achieved, return to the previous step and continue heating for one more heating step. If homogeneity is achieved, record the homogenization temperature T of the sample. h The homogenization temperature T h This indicates that the saltwater inclusions are in (T)h -T,T h Uniform within the range.

[0050] Step 3: During the measurement process, at T room At temperature +(n+1)T (n=100, then it is 121℃), no obvious bubbles can be observed for the first time. The temperature is then lowered to T. room +nT(120℃), at this temperature, bubbles reappear, indicating that the brine inclusions are not homogeneous and have returned to the temperature T before cooling. room +(n+1)T(121℃), then continue heating by one heating step to reach T. room +(n+2)T(122℃), no bubbles were observed at this temperature, and the temperature was lowered to T. room +nT(120℃), at this temperature, bubbles can still be observed to reappear, indicating that the brine inclusions are still not homogeneous, returning to the temperature T before cooling. room +(n+2)T(122℃), then continue heating in one heating step to reach T. room +(n+3)T(123℃), no bubbles were observed at this temperature, and the temperature was lowered to T. room +nT(120℃), at this temperature no bubbles were observed to reappear, indicating that the brine inclusions were at T room The brine inclusions have reached homogeneity at a temperature of +(n+3)T(123℃). 123℃ is the homogeneity temperature of the brine inclusions, indicating that the brine inclusions are homogeneous within the range of (122, 123).

[0051] The homogenization temperature of the brine inclusion C obtained in Example 3 was 123°C.

[0052] Comparative Example

[0053] This comparative example provides a prior art method for determining the homogenization temperature of brine inclusions. It is applied to brine inclusions A, B, and C. The prior art method directly heats the inclusions and then observes and records the temperature at which the bubbles disappear. The homogenization temperature values ​​of brine inclusions A, B, and C are 80℃, 80℃, and 121℃, respectively.

[0054] Existing technology fails to consider that: the disappearance of air bubbles in an inclusion may be a process, and the temperature recorded by different people will vary greatly; even for the same person with the same inclusion, the temperature measured at different times may also be different.

[0055] In summary, the method for determining the homogenization temperature of brine inclusions in this invention does not require observation of an "instantaneous" homogenization phenomenon. Instead, it uses a heating step size method to constrain the temperature range in which a "homogenization phenomenon" occurs. Based on different temperature step sizes, homogenization temperatures that meet different geological requirements can be obtained. In addition, it does not require observation of an "instantaneous homogenization phenomenon," meaning that the observer does not need to keep staring at a few inclusions. They only need to make judgments at specific observation points. This method can free the observer's eyes, allowing them to observe inclusions in multiple fields of view simultaneously, and improving data reproducibility and accuracy.

[0056] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0057] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for determining the homogenization temperature of brine inclusions, characterized in that, Includes the following steps: Step 1: At room temperature, the sample to be tested is heated by a heating step T using a hot and cold stage. A test kit is used to determine whether the sample has reached homogeneity. The test kit determines whether the sample has reached homogeneity based on whether the bubbles in the sample have completely disappeared. Step 2: If uniformity is not achieved, return to Step 1 and continue heating by one heating step; Step 3: If homogeneity is achieved, record the bubble disappearance temperature T of the sample. miss =T room +nT, Among them, T room The room temperature is 1, and n is an integer greater than or equal to 1. The uniformity temperature T h In (T) room +(n-1)T, T room Within the range of +nT], The complete disappearance of bubbles means that no bubbles can be observed in the sample at a temperature of Troom+nT, and no bubbles can be observed when the temperature is lowered to Troom+(nx)T; where Troom is room temperature, n is an integer greater than or equal to 1, and x is an integer greater than or equal to 1 and x < n; the temperature at which no bubbles can be observed in the sample at Troom+nT is the critical temperature value for the disappearance of bubbles.

2. The determination method according to claim 1, characterized in that, Step 1, in which the inspection package is used to determine whether the sample to be tested has reached homogeneity, further includes: if the sample to be tested is homogeneous within T... room If bubbles can be observed at +mT, the sample to be tested is not homogeneous and the temperature needs to be increased further. m is an integer greater than or equal to 1, where m < nx.

3. The determination method according to claim 1 or 2, characterized in that, In step 1, the heating step size T is 1-10℃ / min.

4. The determination method according to claim 1 or 2, characterized in that, In step 1, after heating by one heating step T, the test sample is checked using an inspection bag to determine whether it has reached uniformity, and then the test sample is kept warm.

5. The determination method according to claim 1 or 2, characterized in that, Step 3 also includes determining the homogenization temperature T. h In (T) room +(n-1)T, T room After reaching the range of +nT], with T room +(n-1)T is the initial temperature. Using T′ as the heating step size, repeat steps 1-3 to obtain the homogenization temperature T. h In (T) room +(n-1)T+(n'-1)T', T room The range is [+(n-1)T+n'T'], where T′<T and n' is an integer greater than or equal to 1.

6. The determination method according to claim 5, characterized in that, Repeat the above steps until a uniform temperature value approximating the point value is obtained.

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