A method for exploring a deep basin brine lithium mine

Abstract

The application discloses a kind of basin deep brine lithium ore exploration methods.The present application relates to the technical field of geological exploration.The present application comprises the following steps: S1, real-time take circulating mud sample in the process of drilling, the drilling mud liquid of sampling is placed for a period of time to obtain clear liquid sample, and the clear liquid is chemically analyzed lithium content;S2, according to the sampling depth, the sampled detritus sandstone core is recorded and described, and the porosity of the detritus rock is observed in the field or tested in the laboratory;S3, according to the lithium content of mud clear liquid and the porosity of detritus rock, the lithium content of brine in the formation detritus rock pore is calculated, and the lithium content of pore water is equal to the lithium content of mud clear liquid divided by the porosity of detritus rock;S4, whether there is brine lithium ore is judged according to the lithium content calculated in step S3.The present application is a kind of basin deep brine lithium ore exploration method, which is low in cost, simple and effective.

Description

Technical Field

[0001] This invention relates to the field of geological exploration technology, and in particular to a method for exploring deep brine lithium deposits in basins. Background Technology

[0002] Lithium is a strategic emerging mineral resource, an important key metallic element, and a "critical energy element" (American Physical Society, 2011). It is a crucial raw material for manufacturing batteries for new energy vehicles. Global lithium resources are abundant in total quantity and diverse in mineralization types, but their distribution is uneven, mainly concentrated in Chile, China, Argentina, and Australia (Kesler et al., 2012). Global lithium production in 2017 was 430,000 tons (Jaskula, 2018). Currently, globally developed lithium resources are divided into two main categories: brine-type and hard-rock-type. Brine-type lithium products account for 75% of global lithium production (Lee et al., 2016), with the majority of production coming from brine-type lithium deposits. Due to environmental, cost, and technological issues, China's hard-rock-type lithium deposits have not yet achieved large-scale, high-efficiency production capacity. However, brine-type lithium resources have already achieved relatively large-scale production capacity in the East and West Tai Salt Lakes of the Qaidam Basin and the Qarhan Salt Lake. These are surface and shallow brine resources (mostly buried at depths of less than 30 meters). Overall, it is predicted that the current proven reserves of lithium brine worldwide still cannot meet long-term market demand (Chenglin Liu, T. Lowenstein, Anjian Wang, Chunmiao Zheng, Jianguo Yu. 2023. Brine: Genesis and Sustainable Resource Recovery Worldwide. DOI: 10.1146 / annurev-environ-112621-094745 Corpus ID: 265175016). Further exploration of resources is needed, especially for deep lithium brine in ancient evaporite basins. Based on modern salt lake lithium occurrence characteristics and exploration technology experience, it is necessary to develop low-cost and effective new technologies and methods for deep-seated lithium brine prospecting.

[0003] Lithium brine deposits, according to domestic salt lake exploration standards, are brine bodies with a lithium chloride content reaching 300 mg / L. A typical lithium brine deposit in China is the underground brine of the Qarhan Beltan Salt Flat, whose chemical composition is shown in Table 1. The average salinity of the brine is 329 g / L, and the average lithium chloride content is 1040 mg / L. Lithium brine deposits include surface brine of salt lakes, intercrystalline brine of halite, clastic porous brine, and brine from fault zones. Shallow lithium brine deposits in salt lakes are generally buried at depths ranging from a few meters to over 200 meters, mostly occurring in the intercrystalline spaces of salt crystals; while deep lithium brine deposits are buried at depths of 200-3000 meters or more, belonging to ancient salt lake origins, and mostly occurring in clastic rocks, volcanic rock pores, and fault zones. Currently... The exploration of shallow brine lithium deposits in salt lakes at home and abroad has been basically completed. The exploration of brine lithium deposits buried at a depth of less than 200 meters in the strata is the main direction of lithium exploration. For example, the western part of the Qaidam Basin, the Sichuan Basin, and the Jianghan Basin. Some of these basins may not have developed a large number of ancient rock salt deposits, but they also produce brine lithium deposits, such as brine lithium deposits in the Jianghan Basin (Gangjia 1 well), the Sichuan Basin and the Jitai Basin in Jiangxi Province. However, brine lithium deposits are also present in the strata (Liu Chenglin, Yu Xiaocan, Zhao Yanjun, Wang Jiuyi, Wang Licheng, Xu Haiming, Li Jian, Wang Chunlian. 2016. Preliminary study on the regional metallogenic background and metallogenic process of liquid potassium and lithium resources in the South China Block [J]. Mineral Deposits Geology, 35(6):1119~1143). Multiple technical methods are needed for exploration. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings of existing technologies by proposing a low-cost, simple, and effective method for exploring deep brine lithium deposits in basins.

[0005] The present invention provides a method for exploring deep brine lithium deposits in a basin, comprising the following steps:

[0006] S1. During the drilling process, circulating mud samples are taken in real time. After the sampled drilling mud is left to stand for a period of time, a clear liquid sample is obtained, and the lithium content of the clear liquid is chemically analyzed.

[0007] S2. The sampled clastic sandstone cores are recorded and described according to the sampling depth, and the porosity of the clastic rocks is visually inspected in the field or tested in the laboratory.

[0008] S3. Calculate the lithium content in the pores of the clastic rocks based on the lithium content of the mud and the porosity of the clastic rocks. The lithium content in the pore water = lithium content in the mud / porosity of the clastic rocks.

[0009] S4. Determine whether brine lithium ore exists based on the lithium content calculated in step S3.

[0010] Furthermore, the drilling mud is drilling mud for other exploration purposes.

[0011] Furthermore, if the lithium content is greater than 25 mg / L, the basin has the potential to find brine lithium deposits.

[0012] Furthermore, the lithium content reached 50 mg / L, indicating that the strata contain brine lithium deposits.

[0013] Furthermore, if the lithium content is less than 25 mg / L, salinity is calculated: S (salinity) = mud slurry salinity / clastic rock porosity; if the salinity reaches 50 g / L, it indicates that the area still has the potential to find lithium deposits.

[0014] Furthermore, drilling mud is obtained by continuously sampling circulating mud at the surface, with drilling mud sampled at intervals.

[0015] Furthermore, drilling mud samples were taken at 5-meter intervals.

[0016] Furthermore, the porosity of the clastic rock is the average porosity content of the clastic rock in each core segment.

[0017] Furthermore, step S4 also includes compiling a vertical lithium content distribution map of the formation based on the calculated lithium content.

[0018] Furthermore, the vertical lithium content distribution map of the strata can be used to determine whether to conduct detailed exploration and mining of lithium.

[0019] Ancient clastic rocks in basins, due to their well-developed porosity, often serve as reservoirs for ancient salt lake brine. If the lithium content in the brine reaches a certain grade, it constitutes a lithium brine deposit. These clastic reservoirs are typically buried at depths of 200-4000 meters, making dedicated exploration, especially coring, very costly. However, lithium deposits can be found using drilling mud from other applications. This invention proposes a technical method based on the principle that if lithium-rich brine is present in the pores of the sandstone clastic rocks, it will mix into the circulating drilling mud during drilling. By analyzing the mud samples, the lithium content and other parameters of the formation brine can be revealed.

[0020] The present invention provides a low-cost, simple, and effective method for exploring deep brine lithium deposits in basins. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the drilling core and annulus.

[0022] Figure 2 A map showing the lithium content distribution in drilling mud from a scientific drilling well in a basin in South China.

[0023] Figure 3 A map showing the salinity distribution of drilling mud from a scientific drilling well in a basin in South China.

[0024] Figure 4 This is a schematic diagram of the distribution of borehole mud samples. Detailed Implementation

[0025] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments.

[0026] The borehole reached a section of the clastic layer core. Figure 1 The rock between the core and the well wall was broken up, and these rock fragments and pore brine mixed with mud and were brought to the surface together.

[0027] Assuming pore saturation is 100% (i.e., 100% filled with brine), the brine volume within the core segment of length H can be calculated as follows: Pore brine volume = H * annular area * porosity, where the annular area = 2 * 3.14(R1 + 20). 2 -2*3.14(R1) 2

[0028] In reality, the brine in these pore volumes has been diluted N times by the drilling mud during the drilling process. The minimum dilution factor should be calculated as follows: the annulus volume is completely filled with drilling mud, and the brine dilution factor = annulus volume / brine volume = (2 * 3.14(R1 + 20)). 2 -2*3.14(R1) 2 ) / (2*3.14(R1+20) 2 -2*3.14(R1) 2 * Clastic rock porosity = 1 / porosity. That is, if the porosity of clastic rock is 5%, then the dilution factor Dn = 1 / clastic rock porosity = 1 / 0.05 = 20.

[0029] Example 1

[0030] (1) Sampling

[0031] By continuously sampling circulating mud from the surface and estimating the depth of each mud sample, the mud is left to stand for a period of time, clarified, and the supernatant is taken for chemical tests such as salinity and lithium content, and a vertical distribution map of lithium and salinity in the strata is compiled.

[0032] (2) Estimation of lithium content in brine

[0033] The lithium content can be estimated based on the dilution factor, using the following formula:

[0034] C (lithium content) = Lithium content of mud slurry * Dn (dilution factor).

[0035] The salinity of the brine can be estimated using the same method.

[0036] S (salinity) = Ns (sludge salinity) * Dn (dilution factor).

[0037] (3) Specific operational results in a certain basin

[0038] Figure 2 This is the lithium analysis result of drilling mud from a basin in South China. Li chemical analysis of the drilling mud revealed lithium-rich strata (…). Figure 2 3) The lithium content ranged from a minimum of 0.03 mg / L to a maximum of 1.8 mg / L, with an average of 1 mg / L; the brine salinity ranged from a minimum of 0.7 g / L to a maximum of 5 g / L, with an average of 2 g / L. The drilled clastic rocks in this basin are fine sandstone with very low porosity, generally measured to be around 2-10%.

[0039] Based on the above parameter calculation method, the lithium content of the formation brine is: 1.8 / 0.1-1.8 / 0.02=18mg / L-90mg / L. The formation salinity content is 5 / 0.1-5 / 0.02=50g / L-250g / L.

[0040] The results above indicate that the area has potential for lithium exploration.

[0041] Sometimes, even with low lithium content estimates, such as a salinity of 50 g / L (the grade of brine), it can indicate that the area has potential for lithium exploration.

[0042] Example 2

[0043] To verify the effectiveness of this technology in finding brine lithium deposits, systematic sampling was conducted on the drilling mud in borehole NX23ZK03 in 2023.

[0044] Drilling mud samples were taken at intervals of approximately 5 meters. Figure 4 This involves sampling at points in the middle of the sample section; the sampling depth is continuously maintained from the beginning, and the mud is left to stand for a period of time to obtain a clear liquid; the liquid is then sent to the laboratory for chemical analysis.

[0045] Chemical analysis of the mud revealed that the lithium content varied from 0.158 mg / L to 0.853 mg / L, which is much higher than the lithium content in local river water and shallow groundwater (lithium is usually undetectable in local river water and shallow groundwater). Since the mud was prepared with local river water, the initial mud itself did not contain lithium, indicating that the water in the sandstone formation has a high lithium content.

[0046] The sandstone core was cataloged and described, and its porosity was visually estimated. Porosity samples were collected and sent for experimental testing. Taking 5% of the average sandstone porosity, the calculated values ​​ranged from 3.16 mg / L to 17.06 mg / L, with an average of 7.72 mg / L.

[0047] Based on this understanding, the pore water in the clastic formations with the previously estimated high lithium content was pumped out. Once the pumped water became clear, formation water samples were taken and sent to the laboratory for chemical analysis. The actual lithium analysis results of the sampled formation water are shown in Table 1. The average lithium content was 6.11 mg / L, which is close to the model-estimated lithium content of 7.72 mg / L, indicating that this prospecting technique is relatively effective.

[0048] Table 1. Lithium content in borehole mud and formation water in a basin of Guangdong Province.

[0049]

[0050]

[0051] For any points not covered above, existing technologies shall apply.

[0052] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of exploration for a deep basin brine lithium deposit characterised by: Includes the following steps: S1. During the drilling process, circulating mud samples are taken in real time. After the sampled drilling mud is left to stand for a period of time, a clear liquid sample is obtained, and the lithium content of the clear liquid is chemically analyzed. S2. The sampled clastic sandstone cores are recorded and described according to the sampling depth, and the porosity of the clastic rocks is visually inspected in the field and tested in the laboratory. S3. Based on the lithium content of the mud and the porosity of the clastic rocks, calculate the lithium content in the pores of the clastic rocks. The lithium content in the pore water = lithium content in the mud / porosity of the clastic rocks. S4. Determine whether brine lithium ore exists based on the lithium content calculated in step S3.

2. A method of exploration for a deep basin brine lithium deposit according to claim 1, characterised in that: The drilling mud is drilling mud for other exploration purposes.

3. A method of exploration for a deep basin brine lithium deposit according to claim 1 characterised in that: If the lithium content in the pore water is greater than 25 mg / L, the basin has the potential to find lithium deposits in brine.

4. The method for exploring deep brine lithium deposits in a basin as described in claim 1, characterized in that: The presence of 50 mg / L lithium in the pore water indicates the presence of brine lithium deposits in the strata.

5. The method for exploring deep brine lithium deposits in a basin as described in claim 1, characterized in that: If the lithium content in the pore water is less than 25 mg / L, then the salinity is calculated: salinity S = mud slurry salinity / clastic rock porosity; if the salinity reaches 50 g / L, it indicates that the basin still has the potential to find lithium deposits.

6. The method for exploring deep brine lithium deposits in a basin as described in claim 1, characterized in that: Drilling mud is obtained by continuously sampling circulating mud from the surface at 5-meter intervals.

7. The method for exploring deep brine lithium deposits in a basin as described in claim 1, characterized in that: The porosity of the clastic rock is the average porosity content of the clastic rock in each core segment.

8. The method for exploring deep brine lithium deposits in a basin as described in claim 1, characterized in that: Step S4 also includes: compiling a vertical lithium content distribution map of the formation based on the calculated lithium content.

9. The method for exploring deep brine lithium deposits in a basin as described in claim 8, characterized in that: Determine whether to conduct detailed lithium exploration and mining based on the vertical lithium content distribution map of the strata.

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