Uranium-rich hydrocarbon source rock evaluation method

Abstract

The invention belongs to the field of uranium ore geology, and particularly relates to a uranium-rich hydrocarbon source rock evaluation method which comprises the following steps: step 1, determining the uranium content of uranium-rich hydrocarbon source rock; 2, determining the volume of the uranium-rich hydrocarbon source rock; and 3, evaluating the uranium supply capability of the uranium-rich hydrocarbon source rock. According to the method, the uranium supply capability of the hydrocarbon source rock can be rapidly and effectively evaluated, so that powerful support is provided for resource evaluation and favorable target areas of sandstone type uranium ores.

Description

Technical Field

[0001] The invention belongs to the field of uranium geology, and in particular relates to a method for evaluating uranium-rich hydrocarbon source rocks. Background Art

[0002] In addition to containing organic matter, source rocks often also have a high uranium content. The latest research shows that there is a new type of uranium mineralization in the sedimentary basins in northern my country - seepage sandstone uranium mineralization. This mineralization emphasizes that uranium-rich reducing fluids from deep source rocks migrate to shallow areas and then accumulate and precipitate to form minerals. Obviously, uranium-rich source rocks are crucial to sandstone-type uranium mineralization.

[0003] However, there is currently no method for evaluating uranium-rich source rocks, which seriously restricts the evaluation of sandstone-type uranium resource potential and even the optimization of favorable mineralization target areas.

[0004] Therefore, a method for evaluating uranium-rich source rocks is urgently needed to provide strong support for resource evaluation and favorable target areas of sandstone-type uranium deposits. Summary of the invention

[0005] The purpose of the present invention is to provide a method for evaluating uranium-rich source rocks, which can quickly and effectively evaluate the uranium supply capacity of source rocks, so as to provide strong support for resource evaluation and favorable target areas of sandstone-type uranium deposits.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] A method for evaluating uranium-rich hydrocarbon source rocks, the method comprising:

[0008] Step 1, determining the uranium-containing properties of uranium-rich source rocks;

[0009] Step 2, determining the volume of uranium-rich source rock;

[0010] Step 3: Evaluate the uranium supply capacity of uranium-rich source rocks.

[0011] The step 1 comprises:

[0012] Step 1.1, source rock sample collection: select source rocks in the basin and collect rock samples;

[0013] Step 1.2, uranium content test: the sample is crushed, dissolved, digested, and the soluble residue is dissolved, and the uranium content of each sample is measured using an online internal standard method on a high-resolution inductively coupled plasma mass spectrometer;

[0014] Step 1.3: Calculate the average uranium content of the uranium-rich source rock based on the measured uranium content of each sample.

[0015] In the step 1.2, the sample is crushed, dissolved, digested, and the soluble residue is dissolved as follows: the sample is crushed and then dried to obtain a dry sample, the dry sample is placed in a sample dissolving tank, water is added to wet it, and it is vibrated to obtain a uniform sample; a digestion solution is added to the uniform sample until the solution is transparent and free of impurities, and then the solution is heated on a low-temperature electric heating plate to dissolve and evaporated until white smoke is eliminated, and the soluble residue is dissolved after the digestion is complete.

[0016] In the step 1.2, the digestion solution used for digestion is a mixed solution of hydrofluoric acid, nitric acid and perchloric acid, with a volume ratio of hydrofluoric acid: nitric acid: perchloric acid = 3:1:1.

[0017] In the step 1.2, dilute nitric acid is used to dissolve the soluble residue, and the volume ratio of the dilute nitric acid is 65% by mass of concentrated nitric acid: deionized water = 1:1.

[0018] The step 2 comprises:

[0019] Step 2.1, determine the area S of the uranium-rich source rock: determine the boundary of the uranium-rich source rock, and the area enclosed by the boundary is the area S of the uranium-rich source rock.

[0020] Step 2.2, determine the volume V of uranium-rich source rock: collect and organize the borehole and seismic data, read the thickness d of the source rock in each borehole and seismic profile, and calculate the volume V of the uranium-rich source rock using the finite element method in combination with the area S of the uranium-rich source rock.

[0021] The step 3 specifically comprises: according to the average uranium content of the uranium-rich source rock And the volume V of uranium-rich source rocks are used to evaluate the uranium supply capacity of uranium-rich source rocks.

[0022] The evaluation criteria for the uranium supply capacity of uranium-rich source rocks in step 3 are:

[0023] ① Uranium-rich source rocks with good uranium supply capacity: And V ≥ 1 × 10 8 m 3 ;

[0024] ② Uranium-rich source rocks with good uranium supply capacity: And 5×10 7 m 3 <V<1×10 8 m 3 ;

[0025] ③Uranium-rich source rocks with medium uranium supply capacity: And 1×10 7 m 3 <V<5×10 7 m 3 ;

[0026] ④ Uranium-rich source rocks with poor uranium supply capacity: And 5×10 6 m 3 <V<1×10 7 m 3 ;

[0027] ⑤ Uranium-rich source rocks with poor uranium supply capacity: V≤5×10 6 m 3 .

[0028] The beneficial technical effects of the present invention are:

[0029] 1. The method for evaluating uranium-rich source rocks provided by the present invention is applicable to various geological bodies containing source rocks, and can quickly and effectively evaluate the uranium supply capacity of source rocks, so as to provide strong support for resource evaluation and favorable target areas of sandstone-type uranium deposits.

[0030] 2. Compared with the comprehensive evaluation method of uranium-rich geological bodies, the method for evaluating uranium-rich source rocks provided by the present invention only uses the average uranium content The uranium supply capacity of uranium-rich source rocks is evaluated by using two key evaluation parameters: the volume V of uranium-rich source rocks. The operation is simple and fast.

[0031] 3. Compared with other evaluation methods, the method for evaluating uranium-rich source rocks provided by the present invention provides a quantitative evaluation standard for the uranium supply capacity of uranium-rich source rocks, which is more operational. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention provides a flow chart of a method for evaluating uranium-rich source rocks. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0034] like Figure 1 As shown, the present invention provides a method for evaluating uranium-rich hydrocarbon source rocks, which specifically includes the following steps:

[0035] Step 1, determining the uranium-containing properties of uranium-rich source rocks;

[0036] Step 1.1, source rock sample collection: select source rocks in the basin and collect n rock samples, n is generally 10 to 20, each sample weighs 20 to 50g, and the samples must be fresh and not weathered or polluted;

[0037] Step 1.2, uranium content test: put each sample into a sample crusher and crush it to 200 mesh. After drying the crushed sample at 60°C for 4h, obtain a dry sample. Accurately weigh 0.05g of the dry sample into a polytetrafluoroethylene sealed sample dissolving tank, first moisten it with a small amount of water, and gently shake it to make the sample uniform; add 3ml of hydrofluoric acid, 1ml of nitric acid and 1ml of perchloric acid, and cover the special sample dissolving tank cover; heat and dissolve on a low-temperature electric hot plate at 150°C for 72h, open the sample dissolving tank, if the solution is not transparent or has impurities, add 3ml of hydrofluoric acid, 1ml of nitric acid and 1ml of perchloric acid again to repeat the above digestion process until the solution is transparent and free of impurities, then heat and evaporate to dryness on a low-temperature electric hot plate until white smoke is gone, add 2ml of dilute nitric acid with a mass fraction of 65% by volume: deionized water = 1:1, cover the special sample dissolving tank cover and simmer for a period of time to dissolve the soluble residue. Dilute to 50 ml with high-purity water, shake well, and measure the uranium (U) content of each sample using an online internal standard (10 ng / ml Rh standard solution) on a high-resolution inductively coupled plasma mass spectrometer (ICP-MS). i )content.

[0038] Step 1.3. Calculate the average uranium content Use the following formula to obtain

[0039]

[0040] Step 2, determining the volume of uranium-rich source rock;

[0041] Step 2.1, determine the area (S) of uranium-rich source rock: collect and organize the drilling and seismic data, screen the thickness of the source rock in each drilling and seismic profile, and determine the place where the source rock thickness is 0 as the boundary of the uranium-rich source rock. The area enclosed by the boundary is the area (S) of the uranium-rich source rock.

[0042] Step 2.2, determine the volume (V) of uranium-rich source rock: collect and organize the borehole and seismic data, read the thickness (d) of the source rock in each borehole and seismic profile, combine it with the area (S) of the uranium-rich source rock, and use the finite element method to calculate the volume (V) of the uranium-rich source rock.

[0043] Step 3: Evaluation of uranium supply capacity of uranium-rich source rocks;

[0044] Obtaining the average uranium content of uranium-rich source rocks After calculating the volume (V) of uranium-rich source rocks, the uranium-rich source rocks are classified into five different levels: very good, good, medium, poor, and very poor according to the following standards:

[0045] ① Uranium-rich source rocks with good uranium supply capacity: And V ≥ 1 × 10 8 m 3 ;

[0046] ② Uranium-rich source rocks with good uranium supply capacity: And 5×10 7 m 3 <V<1×10 8 m 3 ;

[0047] ③Uranium-rich source rocks with medium uranium supply capacity: And 1×10 7 m 3 <V<5×10 7 m 3 ;

[0048] ④ Uranium-rich source rocks with poor uranium supply capacity: And 5×10 6 m 3 <V<1×10 7 m 3 ;

[0049] ⑤ Uranium-rich source rocks with poor uranium supply capacity: V≤5×10 6 m 3 .

[0050] The present invention is described in detail above with reference to the accompanying drawings and embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The contents not described in detail in the present invention can adopt the existing technology.

Claims

1. A method for evaluating uranium-rich source rocks, characterized in that: The method comprises: Step 1, determining the uranium-containing properties of uranium-rich source rocks; Step 2, determining the volume of uranium-rich source rock; Step 3: Evaluate the uranium supply capacity of uranium-rich source rocks.

2. The method for evaluating uranium-rich source rocks according to claim 1, characterized in that: The step 1 comprises: Step 1.1, source rock sample collection: select source rocks in the basin and collect rock samples; Step 1.2, uranium content test: the sample is crushed, dissolved, digested, and the soluble residue is dissolved, and the uranium content of each sample is measured using an online internal standard method on a high-resolution inductively coupled plasma mass spectrometer; Step 1.3: Calculate the average uranium content of the uranium-rich source rock based on the measured uranium content of each sample.

3. The method for evaluating uranium-rich source rocks according to claim 2, characterized in that: In step 1.2, The sample is crushed, dissolved, digested, and the soluble residue is dissolved as follows: the sample is crushed and then dried to obtain a dry sample, the dry sample is placed in a sample dissolving tank, water is added to moisten and vibrate to obtain a uniform sample; a digestion solution is added to the uniform sample until the solution is transparent and free of impurities, then heated on a low-temperature electric heating plate to dissolve, evaporated to dryness until white smoke is eliminated, and the soluble residue is dissolved after complete digestion.

4. The method for evaluating uranium-rich source rocks according to claim 3, characterized in that: In the step 1.2, the digestion solution used for digestion is a mixed solution of hydrofluoric acid, nitric acid and perchloric acid, with a volume ratio of hydrofluoric acid: nitric acid: perchloric acid = 3:1:

1.

5. The method for evaluating uranium-rich source rocks according to claim 3, characterized in that: In the step 1.2, dilute nitric acid is used to dissolve the soluble residue, and the volume ratio of the dilute nitric acid is 65% by mass of concentrated nitric acid: deionized water = 1:

1.

6. The method for evaluating uranium-rich source rocks according to claim 2, characterized in that: The step 2 comprises: Step 2.1, determine the area S of the uranium-rich source rock: determine the boundary of the uranium-rich source rock, and the area enclosed by the boundary is the area S of the uranium-rich source rock. Step 2.2, determine the volume V of uranium-rich source rock: collect and organize the borehole and seismic data, read the thickness d of the source rock in each borehole and seismic profile, and calculate the volume V of the uranium-rich source rock using the finite element method in combination with the area S of the uranium-rich source rock.

7. The method for evaluating uranium-rich source rocks according to claim 6, characterized in that: The step 3 specifically comprises: according to the average uranium content of the uranium-rich source rock The uranium supply capacity of uranium-rich source rocks is evaluated based on the volume V of uranium-rich source rocks.

8. The method for evaluating uranium-rich source rocks according to claim 7, characterized in that: The evaluation criteria for the uranium supply capacity of uranium-rich source rocks in step 3 are: ① Uranium-rich source rocks with good uranium supply capacity: And V ≥ 1 × 10 8 m 3 ; ② Uranium-rich source rocks with good uranium supply capacity: And 5×10 7 m 3 <V<1×10 8 m 3 ; ③Uranium-rich source rocks with medium uranium supply capacity: And 1×10 7 m 3 <V<5×10 7 m 3 ; ④ Uranium-rich source rocks with poor uranium supply capacity: And 5×10 6 m 3 <V<1×10 7 m 3 ; ⑤ Uranium-rich source rocks with poor uranium supply capacity: V≤5×10 6 m 3 .

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