Measurement and analysis method using borehole for quantitatively discriminating deep-sea hydrothermal sulfide and base rock at original position

Abstract

To provide a measurement and analysis method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfide and a base rock at an original position.SOLUTION: Measurement and analysis means using a feasible borehole is proposed, to achieve the purpose of accurate discrimination of the distribution state and the relative content of sulfide and a base rock in the entire borehole cross section. A measurement and analysis method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfide and a base rock at an original position includes: a step 1 of boring and coring in a sulfide mining area, executing multi-parameter measurement in the borehole, and dividing a rock layer part layer from top to bottom on the basis of a measurement curve; a step 2 of executing an indoor physical property test and layer-specific identification, test, and calculation by a microscope on a core sample; a step 3 of establishing a discriminant of the sulfide and base rock in a laboratory environment; and a step 4 of substituting the average value of a boring measurement curve of each part layer into the discriminant obtained in step 3, and calculating the relative content of the sulfide and base rock in each part layer of the entire cross section.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the field of evaluation research on deep-sea hydrothermal sulfide resources, and particularly to a measurement and analysis method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfide and its host rock in-situ.

Background Art

[0002] Deep-sea hydrothermal sulfide is a metallic mineral resource widely distributed in deep-sea environments such as mid-ocean ridges, back-arc basins, and island arcs, and has important economic value and the potential for development and utilization.

[0003] Deep-sea hydrothermal sulfide coexists with the host rock (surrounding rock) beneath the seabed and can mix to form sediments with a thickness exceeding 100 m. The consolidation degree of this sediment is poor, resulting in extremely low core sampling efficiency, often less than 40%. Since each layer of coring is usually discontinuous, it was not possible to directly evaluate the resource potential with core samples. Based on the above reasons, it is necessary to carry out in-situ physical property measurements using a borehole, and perform fitting analysis by combining the indoor physical property test characteristics of borehole core samples to analyze the distribution and relative content of sulfide and host rock in each layer, which is the necessary method for accurately evaluating the deep-sea sulfide resource potential.

[0004] Currently, there are few borehole surveys in deep-sea hydrothermal sulfide areas, and even fewer measurement operations in boreholes. The related theoretical basis and methods for analyzing the mineral content of borehole rock layers are still immature, significantly restricting the accurate understanding of the value of deep-sea sulfide resources in the scientific community and the industrial community, as well as the work of preparation for development and utilization. Currently, the development of a measurement and analysis method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfide and its host rock in-situ is an urgent task.

[0005] In view of the above circumstances, this patent application is filed.

Summary of the Invention

Problems to be Solved by the Invention

[0006] A measuring and analyzing method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfide and bedrock in-situ, which solves the problems and needs existing in the above prior art, and proposes a feasible measuring and analyzing means using a borehole to accurately discriminate the distribution status and relative content of sulfide and bedrock in the entire cross-section of the borehole in order to achieve the purpose of accurately discriminating the distribution status and relative content of sulfide and bedrock in the entire cross-section of the borehole.

Means for Solving the Problem

[0007] In order to achieve the above design objective, a measuring and analyzing method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfide and bedrock in-situ, Step 1: Bore and core in a sulfide ore area, perform multi-parameter measurement in the borehole, and divide the rock layer from top to bottom based on the measurement curve; Step 2: Perform indoor physical property tests, layer-by-layer identification and tests, and calculations on the core samples using a microscope; Step 3: Establish a discriminant formula for sulfide and bedrock in a laboratory environment; and Step 4: Substitute the average value of the borehole measurement curve of each layer into the discriminant formula obtained in Step 3, and calculate the relative content of sulfide and bedrock in each layer of the entire cross-section. It is a method including the above steps.

[0008] Also, the above Step 1 includes the following steps, that is, A step of boring and coring on the seabed surface in a deep-sea sulfide ore area; After coring is completed, vertically lower a physical property measuring instrument to the center of the borehole and start the measurement work over the entire length of the borehole; When there are more measurement curves, select the most stable curve as the reference, and correct the depth range of other curves; and A step of dividing the entire measurement cross-section into a plurality of layers from top to bottom with the point of the intermediate depth value between the maximum value and the adjacent minimum value of the measurement curve, or the point of the intermediate depth value between the minimum value and the adjacent maximum value of the measurement curve as the boundary.

[0009] Also, step 2 includes the following steps, namely, immersing the core sample collected from the deep-sea boring hole in seawater at the same temperature and pressure as during coring, and performing continuous physical property tests from top to bottom, and after the test, taking out the sample, performing layer discrimination, testing, and calculation with a microscope to obtain the relative content values of sulfide and the mother rock in each layer.

[0010] Also, in step 2, the seawater temperature in the laboratory is measured by lowering the temperature probe of the measuring instrument into the boring hole, and the seawater surface pressure in the laboratory is calculated from the water depth value of the single beam or the central beam of the multi-beam on the seabed surface of the boring hole.

[0011] Also, step 3 includes the following steps, namely, establishing the discrimination criteria for sulfide and the mother rock in the laboratory environment based on the multi-parameter physical property measurement method, and there is a polynomial function relationship between the induced resistivity, the acoustic wave velocity, and the relative content of sulfide or the mother rock, and performing polynomial regression analysis based on the induced resistivity, the acoustic wave velocity, and the relative content of sulfide measured in each layer in step 2 to obtain the following fitting formula. The fitting formula is

[0012]

Equation

[0013] Also, step 4 includes the following steps, namely, Reading the curve values corresponding to each depth value in different layers on the physical property exploration curve of the cross-section of the boring hole, and calculating the average value of each physical property parameter of each layer, and substituting the average values of the induced resistivity and acoustic wave velocity of each layer calculated into the fitting formula (1) obtained in Step 3 to obtain the relative ratio of sulfide and host rock in each layer on the cross-section measurement curve of the boring hole. This method includes the above steps.

Advantages of the Invention

[0014] Generally speaking, as the advantages of the measurement and analysis method using a boring hole for quantitatively discriminating deep-sea hydrothermal sulfide and host rock in-situ proposed in this application, it effectively solves the lack of relevant theories and methods for quantitatively discriminating sulfide and host rock in the longitudinal section of deep-sea hydrothermal sulfide sediments in the prior art, proposes specific and feasible boring investigation and analysis means, and can accurately identify the distribution and relative content of sulfide and host rock in the entire cross-section of the boring hole. This provides a relevant theoretical basis and technical reference for the accurate evaluation, development and utilization of deep-sea hydrothermal sulfide resources.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0016] Hereinafter, the present invention will be further described with reference to the drawings and embodiments.

[0017] (First Embodiment) The measurement and analysis method using a boring hole for quantitatively discriminating deep-sea hydrothermal sulfide and host rock in-situ proposed by this application includes the following implementation steps.

[0018] Step 1: Drill and core in the sulfide ore area, conduct multi-parameter measurements in the borehole, and divide and classify the rock layers from top to bottom based on the measurement curves. Select a flat seabed surface in the deep-sea sulfide ore area, and drill vertically downward through a seabed drilling machine, a drilling survey platform or a dredger for coring. After coring is completed, lower a physical property measuring instrument vertically to the center of the borehole and start the measurement operation over the entire length of the borehole. Specifically, taking the measuring instruments for induced resistivity (unit: Ω·m) and acoustic wave velocity (unit: μm / s) as an example, if there are differences between the measurement curves when the instrument is lowered and when it is pulled up, the measurement curve when the instrument is pulled up shall be taken as the final result. Since acoustic wave measurement is relatively susceptible to the influence of external interference factors such as small-particle sediments and pores in the borehole wall, based on a relatively stable induced resistivity curve, correct the depth values of the acoustic wave velocity curve to match the induced resistivity curve, and keep the depth ranges of the two measurement curves consistent. In the case of more measurement curves, similarly select the most stable curve as the reference and correct the depth ranges of the other curves. Taking the point of the intermediate depth value between the maximum value and the adjacent minimum value of the measurement curve, or the point of the intermediate depth value between the minimum value and the adjacent maximum value of the measurement curve as the boundary, divide the entire measurement section into multiple layers from top to bottom. At this time, sulfides and host rocks within each layer are evenly distributed. The maximum or minimum value point of the measurement curve is determined by the following formula.

[0019]

Equation

[0020] Step 2: Conduct in - situ physical property tests, layer - by - layer identification by microscope, and test calculations on core samples Immerse the core samples collected from the deep - sea boring hole in seawater at the same temperature and pressure as during coring, and conduct continuous physical property tests from top to bottom. The seawater temperature in the laboratory is measured by lowering the temperature probe of the measuring instrument into the boring hole, and the seawater surface pressure in the laboratory is calculated from the water depth value of the single - beam or multi - beam central beam at the seabed surface of the boring hole. Taking the measurement methods of induced resistivity and acoustic velocity as examples, when conducting in - situ physical property tests on core samples, the distance between the detector and the sample is the same as the distance between the equipment in the boring hole and the hole wall. Here, the acoustic velocity is the longitudinal wave velocity, which is measured by an acoustic detector, and this value is obtained by dividing the sound distance of the sample by the time it takes for the sound wave to pass through the sample. The induced resistivity is measured by an electrical property measuring instrument, and this value is obtained by dividing the product of the sample cross - sectional area and the resistance value by the length between the two measurement electrodes. After the test, take out the samples, conduct layer - by - layer identification by microscope and test calculations to obtain the relative content values of sulfide and parent rock in each layer. These core samples are stored under the seabed surface of the hot water area, and since the oxide content is extremely low, the oxide component can be ignored, and only the relative content of parent rock and sulfide is considered. After slicing the sample to a certain thickness, it is polished into an optical section, and the entire optical section is observed under a microscope. Since there is a significant difference in the reflected luster between the minerals constituting the rock and the minerals constituting the sulfide, most of the rock minerals have a vitreous luster or a greasy luster, while the sulfide minerals have an obvious metallic luster. Therefore, by surrounding all the minerals with metallic luster on the optical section with a circle, summing up the area of the circled region, and then dividing by the area of the entire sample, the relative area content of the sulfide can be obtained. Next, multiplying the relative area content of the sulfide by the density of the sulfide at the layer position and dividing by the sum of the products of the densities of the sulfide and the host rock respectively, the relative content ratio of the sulfide and the host rock can be obtained.

[0021] The densities of the sulfide and the host rock in the core sample at each layer position are obtained by dividing the weights of the sulfide and the host rock samples selected under the microscope by their volumes, where the weights are obtained by weighing with an electronic balance and the volumes are obtained by the drainage method.

[0022] The calculation formula for the sulfide content in the core sample is shown as follows.

[0023]

Number

[0024] The calculation formula for the host rock content in the core sample is shown as follows.

[0025]

Number

[0026] Step 3: Establish the discriminant formula for sulfides and host rocks in the laboratory environment Based on the multi-parameter physical property measurement method, establish the discrimination criteria for sulfides and host rocks in the laboratory environment. Taking the measurement methods of induced resistivity and acoustic wave velocity as examples, firstly, since deep-sea hydrothermal sulfides are formed by the combination of metal cation substances and sulfide anions, they have strong conductivity, and their induced resistivity is lower than that of the host rocks formed by the condensation of magma. Secondly, since deep-sea hydrothermal sulfides are precipitated and deposited from hydrothermal fluids without compression or metamorphism, they have a higher porosity than the host rocks, and the acoustic wave propagation velocity is slower than that of the host rocks. Based on the above relationships, it can be judged that there is a polynomial function relationship among the induced resistivity, acoustic wave velocity, and the relative content of sulfides or host rocks. By citing the induced resistivity, acoustic wave velocity, and relative content of sulfides measured in each layer in Step 2 and performing polynomial regression analysis and fitting, the following formula can be obtained.

[0027]

Equation

[0028] Step 4: Substitute the average value of the boring measurement curve of each layer into the discriminant formula obtained in Step 3 to calculate the relative content of sulfides and host rocks in each layer of the entire cross-section Read the curve values corresponding to each depth value in different layers on the physical property exploration curve of the boring hole cross-section, and calculate the average value of each physical property parameter of each layer. Taking the induced resistivity (R) and the sonic velocity (S) as examples, the average values of the induced resistivity and the sonic velocity of each layer calculated are substituted into the fitting formula (1) obtained in step 3 to determine the relative ratio of sulfide to the host rock of each layer on the total cross-section measurement curve of the borehole. The results of the measurement analysis using the borehole are shown in Fig. 1.

[0029] As described above, by combining the contents of the means shown in the drawings and the description, similar technical means can be derived, but they still fall within the scope of the rights of the technical means of the present invention.

Claims

1. A measurement and analysis method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfides and host rocks in-situ, comprising: Step 1: Drilling and coring in a sulfide ore area, performing multi-parameter measurements in the borehole, and dividing the rock layers from top to bottom based on the measurement curves; Step 2: Conducting indoor physical property tests, layer-by-layer identification by microscope, and tests and calculations on the core samples; Establishing discrimination criteria for sulfides and host rocks in a laboratory environment based on a multi-parameter physical property measurement method, and there is a polynomial function relationship among the induced resistivity, acoustic velocity, and relative content of sulfides or host rocks. Performing polynomial regression analysis based on the induced resistivity, acoustic velocity, and relative content of sulfides measured in each layer in Step 2 to obtain the following fitting formula, where the fitting formula is: 【Number 1】 wherein R and S respectively represent the value of the induced resistivity and the value of the acoustic velocity of a certain rock layer, and a ｎ to a ０ and b ｎ to b ０ are the coefficients of a polynomial, and a constant value is obtained after polynomial fitting. P ｓ represents the relative content ratio of sulfide in a certain layer, and P ｓ = [0, 1], and when P ｓ = 1, the entire layer is sulfide, and when P ｓ = 0, the entire layer is the parent rock. Step 3: Establishing a discrimination formula for sulfides and host rocks in a laboratory environment, and Step 4: Reading the curve values corresponding to each depth value in different layers on the physical property exploration curve of the borehole cross-section, calculating the average value of each physical property parameter of each layer, and substituting the calculated average values of the induced resistivity and acoustic velocity of each layer into the fitting formula (1) obtained in Step 3 to obtain the relative ratio of sulfides and host rocks in each layer on the full cross-section measurement curve of the borehole. Substituting the average value of the borehole measurement curve of each layer into the discrimination formula obtained in Step 3 to calculate the relative content of sulfides and host rocks in each layer of the full cross-section. A measurement and analysis method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfides and host rocks in-situ, characterized by comprising the above steps.

2. The Step 1 includes: Drilling and coring on the seabed surface of a deep-sea sulfide ore area; After coring is completed, vertically lowering a physical property measuring instrument to the center of the borehole and starting the measurement work over the entire length of the borehole; When there are more measurement curves, selecting the most stable curve as a reference and correcting the depth ranges of other curves; and Dividing the entire measurement cross-section into a plurality of layers from top to bottom with the point at the middle depth value between the maximum value and the adjacent minimum value of the measurement curve, or the point at the middle depth value between the minimum value and the adjacent maximum value of the measurement curve as the boundary. A measurement and analysis method using a borehole for quantitatively discriminating deep-sea hydrothermal sulfides and host rocks in-situ according to Claim 1, characterized by comprising the above steps.

3. The Step 2 includes: The step of immersing a core sample collected from a deep-sea boring hole in seawater at the same temperature and pressure as during coring and performing continuous physical property tests from top to bottom, and the step of, after the test, taking out the sample, performing layer discrimination by microscope and tests / calculations, and obtaining the values of the relative contents of sulfide and host rock in each layer A measurement and analysis method using a boring hole for quantitatively discriminating deep-sea hydrothermal sulfide and host rock in-situ according to claim 1, characterized by including the above steps.

4. The measurement and analysis method using a boring hole for quantitatively discriminating deep-sea hydrothermal sulfide and host rock in-situ according to claim 3, characterized in that in step 2, the seawater temperature in the laboratory is measured by lowering a temperature probe of a measuring instrument into the boring hole, and the seawater surface pressure in the laboratory is calculated from the water depth value of the single beam or the central beam of the multi-beam on the seabed surface of the boring hole.

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