Process for prospecting for natural gas in marine sediments using immobilized microparticle voltammetry

Description

15 PROCESS FOR PROSPECTING FOR NATURAL GAS IN MARINE SEDIMENTS USING MICROPARTICLE VOLTAMMETRY IMMOBILIZED Field of invention [1] This invention patent describes the screening of the voltammetric profile of marine sediments susceptible to the presence of natural gas, with the aim of developing a geochemical prospecting method using voltammetry of immobilized microparticles (VIMP). This study is based on the identification of the electrochemical profile of the sediments obtained directly in the solid state, where the samples are inserted into the composition of a paste electrode, providing an efficient, simple, fast and practical method. [2] It is known that due to their vastness, the oceans play a fundamental role in the development of the global economy, contributing to a variety of activities essential to human beings (Carvalho, 2018). Converging to have a significant role in the Gross Domestic Product (GDP) of countries, in addition to activities such as fishing and agriculture, maritime transport, tourism and shipbuilding, the renewable and non-renewable energy sector, as well as related studies, plays an important role in this environment (Castro et al. 2017). [3] In this context, natural gas is a non-renewable resource composed of light hydrocarbons from the alkane series, which are often associated with CO2, N, CO, H2S and others (Reis et al. 2018; Speight 2018). In underground sedimentary basins, natural gas can occur alongside subsurface reservoirs in three distinct forms: i) in contact with and forming gaseous layers over liquid hydrocarbon, ii) dissolved in petroleum, or iii) as the dominant hydrocarbon (Gutierrez 2022). These characteristics, combined with factors such as origin (whether thermogenic, biogenic, or inorganic), and the quality and composition of the rocks, are key factors. Petition 870250013816, dated 20 / 02 / 2025, page 10 / 38 / 15 generating factors, thermal maturity, interaction with other basin fluids, or even degradation by bacteria in the subsurface that will effectively determine the composition of this material (Speight 2018). [4] In terms of applicability, although it does not yet compare to the use of petroleum, natural gas is considered the third most consumed fossil fuel in the world and its application extends from electricity generation for domestic and commercial consumption to use in transport and industrial activity (Reis et al. 2018). Since it has good efficiency and its combustion emits considerably smaller amounts of pollutants and greenhouse gases, its demand has been increasing, which has directly resulted in the search for more practical and faster methods of prospecting for this material (Reis et al. 2018). [5] Natural gas prospecting can be used to identify the activity of a mud volcano, since the fluid expelled by this type of geological structure is a mixture of particulate matter with water and natural gas (mostly methane, but containing ethane and propane in smaller concentrations, along with carbon dioxide and nitrogen gas) (Mazzini and Etiope, 2017). Since these gases contribute to the greenhouse effect and are released on a large scale during the eruption of these volcanoes, identifying the activity of these volcanoes encompasses both economic (natural gas prospecting) and environmental interests. [6] Voltammetric techniques, such as VIMP, have great potential for application in prospecting for natural resources, such as natural gas, since they have proven efficiency in detecting organosulfur compounds in samples of asphalt cement derived from petroleum (Silveira et al. 2018), metals in copper coins (Doménech-Carbó et al 2010), or even nitrogen compounds in solid solutions of hexacyanometalates (Widmann et al. 2002). [7] In this way, VIMP enters the field of research as an alternative that requires minimal sample preparation and instrumentation. Petition 870250013816, dated 20 / 02 / 2025, page 11 / 38 / 15 compact (Fiedler and Scholz 2005), where the analytical signal obtained is derived from oxidation-reduction processes of electroactive species present in the sample in a solid state immobilized on the surface or in the composition of the electrode (Scholz 2015; Doménech-Carbó et al 2015). [8] In the face of overcoming the difficulties of conventionally used complementary techniques, the present study demonstrates the potential of VIMP in the development of a solid-state voltammetric screening method, aiming at natural gas prospecting through the analysis of the electrochemical profile of marine sediment samples. Fundamentals of the invention [9] This patent application proposes the development of a geochemical prospecting method for natural gas, characterized by its low cost and minimal sample preparation requirements, using the VIMP technique. In order to demonstrate the novelty of this prospecting process, a background search was conducted in several patent databases (international and national). Thus, searches were carried out in the Canadian Intellectual Property Office (CIPO), DEPATISnet, ESPACENET, PATENTSCOPE, National Institute of Industrial Property (INPI), GOOGLE PATENTS, United States Patent and Trademark Office (USPTO) and LATIPAT.For this purpose, different combinations of keywords were used, such as "mud volcano" and "voltamometry" and "plume" and "natural gas" or "mud volcano" and "voltamometry" and "plume" or "mud volcano" and "voltamometry" and "natural gas" or "mud volcano" and "plume" and "natural gas" or "mud volcano" and "plume" or "plume" and "voltamometry" or "mud volcano" and "voltamometry" or "plume" or "mud volcano" and "active plume", in the respective languages ​​of the databases.

[10] In the DEPATISnet database, the previously described keywords were used, yielding several documents as a result of this search. Among them, using the combination of keywords “mud volcano” and “plume” yielded two important documents. The first, CN109376629A, Petition 870250013816, dated 20 / 02 / 2025, page 12 / 38 / 15 describes the development of a method capable of identifying mud volcanoes on the seabed using multibeam depth maps and bottom reflection maps. The technique involves overlaying different types of maps, such as peak point maps, mean square deviation maps, and bottom reflection maps, to more accurately locate areas that indicate the presence of mud volcanoes. This method is especially advantageous for detecting microtopographies, which may include small and sometimes difficult-to-observe topographic features, such as submarine mud volcanoes, especially small ones. The invention also stands out for its ability to reduce errors of judgment and omissions, which can occur due to uncertain topographic features or variable periods of volcanic activity.

[11] The second, CN112363212A, refers to a method for establishing a model of the relationship between plume gas content and seismic attributes, as well as its applications. The said relationship is established from steps such as: (i) establishing a plume model according to the characteristics of seawater containing bubbles; (ii) performing reverse migration processing on the data collection records of the plume model established in the first step, in order to obtain a seismic migration section; (iii) extracting attributes from the seismic migration profile; (iv) fitting the value of the seismic attribute extracted in the third step with the corresponding gas content to obtain a model of the relationship between the plume gas content and the seismic attribute.According to the inventors, the model of the relationship between gas content and seismic attributes is applied to the inversion of the gas content of the actual seismic plume profile, since the distribution condition of the gas bubble content can be visually reflected, and a basis is established to further estimate the plume gas content and hydrate reserve. However, in both documents (CN109376629A and CN112363212A) the inventors do not report the use of voltammetry during the execution of the methods, thus differing from the present patent application. Petition 870250013816, dated 20 / 02 / 2025, p. 13 / 38 / 15

[12] Evaluating the ESPACENET patent database, several documents were found from the search performed with the previously mentioned keyword combinations. Of particular note is the combination of the keywords mud volcano and plume, which resulted in the location of document JP2005024366A. This document describes a system capable of estimating and calculating, in real time, the area affected by a lava flow during a volcanic eruption. This takes into account terrain altitude measurements as an initial value, crater position, as well as thermal analysis and flow rate of lava fluids. These measurements are performed using distance measuring equipment and thermometers. These devices are used to monitor the area already affected by the lava flow, as well as to measure the altitude distribution and temperature on the upper surface of the lava flow, generally from an aerial perspective.With these measurements, the system is able to calculate the affected area, the thickness of the lava, the total volume of the flow, the flow rate, and the temperature. Based on the measured parameters, the system can predict the area that will be affected by the lava flow. This system not only improves the accuracy in estimating the propagation of the lava flow, but also allows for a real-time response, crucial for volcanic disaster management and risk mitigation. However, the inventors do not report the use of voltammetry during the system's operation, thus differentiating it from the present patent application.

[13] Regarding the GOOGLE PATENTS database, several documents were found using the keyword combinations mentioned above. However, the combination mud volcano and plume stood out with an interesting document. Document CN113123421A deals with the invention of a process capable of providing an ecological drought water stream, which has regulation, storage and purification functions. Its objective is to correct the defects in which ecological drought watercourses are insufficient in regulation and storage capacity, since the plants in the drought watercourse become Petition 870250013816, dated 20 / 02 / 2025, p. 14 / 38 / 15 waterlogged during the heavy rainy seasons and the plants in the dry watercourse grow poorly to the point of dying.For this purpose, the inventors report that the following steps are necessary for the construction of the ecological water stream: (i) positioning of the plan and elevation measurement; (ii) construction drainage; (iii) earthwork excavation; (iv) installation of an overflow well; (v) soil compaction; (vi) use of two cloth geotextiles and a membrane; (vii) use of permeable bottom geotextiles; (viii) use of crushed stone with a particle size of 20-50 mm; (ix) use of piping; (x) use of crushed stone with a particle size of 10-20 mm; (xi) use of permeable top geotextile; (xii) use of medium soil fill; (xiii) sedimentation by sprinkling and water permeability testing; (xiv) use of medium and coarse sand; (xv) closing of the fill overflow well; (xvi) spreading of river stones; (xvii) complete placement of pebbles; (xviii) planting of shrubs in the soil; (xix) transplanting of lawn; (xx) maintenance of nursery stock.However, the inventors do not report the detection of gas in active plumes, nor do they present the use of voltammetry during the execution of the method, thus differentiating themselves from the present patent application.

[14] On the other patent search platforms mentioned, several documents were found, but no invention combines the development of a geochemical prospecting method for natural gas and VIMP. This highlights the importance of filing this patent, both nationally and internationally.

[15] Few research articles were found on scientific data search platforms, such as Science Direct and Web of Science, which highlight the importance of research in geochemical prospecting for natural gas using different techniques.

[16] Ijiri et al. (2023) present an investigation into the origin of sediments and fluids ejected by four mud volcanoes located along Tanegahima Island, Japan. To do this, the researchers identified the mineral composition, focusing on the presence of illite and smectite, using the technique of Petition 870250013816, dated 20 / 02 / 2025, page 15 / 38 / 15 X-ray diffraction and vitrinite reflectance analyses. In addition, the study considered the concentration of chloride and sulfate ions present in pore water samples, analyzed by ion-exchange chromatography. Isotopic compositions (δD and δ18O) were determined by laser absorption spectroscopy, while the beryllium isotopic ratio (10Be / 9Be) was evaluated by accelerator mass spectrometry. The concentration of dissolved inorganic carbon (DIC) in the pore water samples and the carbon isotopic compositions (δ13C-DIC) were analyzed by gas chromatography coupled to isotopic ratio mass spectrometry.To determine the origin of the gaseous hydrocarbons, the chemical and isotopic composition (δ13CCH4 and δD-CH4) of methane and ethane were analyzed using gas chromatography coupled with isotope ratio mass spectrometry with isotope monitoring and combustion mass spectrometry. However, the authors do not mention the use of voltammetry during the execution of the method, thus differentiating it from this present patent application.

[17] Thus, it is clear that there is still a gap in the use of VIMP, a fast and economical technique that requires minimal sample preparation, for geochemical prospecting of natural gas, highlighting the importance of this patent. Description of the drawings

[18] The following figures illustrate the process used in the present invention, which consists of using VIMP to prospect for natural gas in sediment samples in the solid state.

[19] Figure 1 - Schematic of the process for preparing the modified carbon paste electrode used for VIMP analysis to subsequently obtain the diagnostic criterion for natural gas prospecting in solid-state sediment samples, where (a) carbon black, (b) sediment sample, (c) mineral oil, (d) maceration, (e) sediment-modified carbon paste electrode (working electrode), (f) electrochemical cell, (g) electrode Petition 870250013816, dated 20 / 02 / 2025, page 16 / 38 / 15 auxiliary, (h) reference electrode, (i) supporting electrolyte, (j) immobilized microparticles, (k) voltammogram.

[20] Figure 2 - Superposition of voltammograms in the anodic direction of the samples entitled: Background (a), Active Plume (b) and Inactive Plume (c) in 0.1 mol L-1 NaOH. Experimental conditions: Initial E: -1.2 V; Final E: 1.5 V; Step: 4 mV, frequency 5 Hz and amplitude 25 mV. Inset: zoom in the potential range from 0.4 V to 0.8 V

[21] Figure 3 - Superposition of voltammograms in the cathodic direction of the samples entitled: Background (a), Active Plume (b) and Inactive Plume (c) in 0.1 mol L-1 NaOH. Experimental conditions: Initial E: 1.5 V; Final E: -1.2 V; Step: 4 mV, frequency 5 Hz and amplitude 25 mV. Inset: zoom in the potential range from 1.1 V to 0.5 V

[22] Figure 4 - Representation of the diagnostic criterion for natural gas prospecting in sediment samples in the solid state. The electrolyte used to obtain the criterion was 0.1 mol L-1 NaOH, being (a) active plume. Description of the invention

[23] The present patent application relates to the development of a voltammetric screening method using VIMP to obtain a diagnostic criterion for carrying out natural gas prospecting in sediment samples.

[24] Currently, the first step in natural gas prospecting is conducting geophysical studies of a region. The most widely used technique is natural seismic analysis (Sun et al. 2020), in which an air gun fires seismic waves at the sediment. These waves then penetrate and propagate through the sediment, being refracted differently when they come into contact with different sedimentary layers and materials present in the sediment. These refracted waves are then detected, obtaining geological information about the region, which allows the identification of possible reservoirs. However, this type of technique does not confirm the presence of hydrocarbons within the Petition 870250013816, dated 20 / 02 / 2025, page 17 / 38 / 15 possible reservoirs. Furthermore, geophysical investigation alone is not sufficient for natural gas prospecting, requiring complementary studies that identify the chemical composition of water and sediments, so that these may be possible indicators of the presence of gas (Gardioli et al. 2015; Kurniawan et al. 2021; Souza et al. 2015).

[25] Among the most commonly used complementary techniques, gas chromatography coupled with mass spectrometry (GC-MS) and isotope ratio mass spectrometry (IRMS) stand out (Ijiri et al. 2023). However, given the disadvantages related to the large size and cost of the necessary equipment, as well as extensive sample preparation and reagent costs (Ijiri et al. 2023), the search for other equally efficient techniques is of great value to research and the market.In this context, the use of VIMP is suggested as a method for confirming the presence of hydrocarbons.

[26] The proposed method has vast potential for application in the area of ​​natural gas prospecting, since the analyses performed by VIMP are low cost, the equipment used is compact (facilitating use directly on vessels) and allows analysis of samples in the solid state. Unlike conventional methods that generally require extensive sample preparation, which ultimately facilitates exposure, contamination and sample loss, VIMP typically requires only one maceration step. However, the method is not limited to maceration alone, and other sample treatment techniques can be applied.

[27] VIMP analyses utilize a three-electrode system: working electrode, counter electrode, and reference electrode. In this system, the sample must be immobilized directly on the surface of the working electrode. In this context, the use of the carbon paste electrode stands out due to the ease of immobilizing sample microparticles on its surface, the ease of cleaning and renewing the surface, the high chemical inertness, and the wide potential window in which this electrode can be used. This type of electrode Petition 870250013816, dated 20 / 02 / 2025, page 18 / 38 / 15 can be easily manufactured in laboratories by mixing a conductive material (carbon black, carbon nanofibers, carbon nanotubes, graphite, graphene and others) together with a binding material (mineral oil), followed by maceration for homogenization and packaging in a container, in addition to using a metal wire as an electrical contact.

[28] The immobilization of microparticles on the surface of the working electrode can be carried out in different ways, such as by abrasion, drop casting, drop coating, or in the case of carbon paste electrodes, by modifying the electrode with the sample. In this last approach, the sample must be macerated together with the conductive and binder material during electrode fabrication. With regard to the supporting electrolyte, VIMP allows the use of any concentration or pH, provided that the solution is not capable of solubilizing the sample and that it can conduct sufficient electric current to oxidize and / or reduce the analyte of interest.

[29] The present method seeks to develop a voltammetric screening method to develop a diagnostic criterion in order to identify the presence of natural gas in solid-state sediment samples. For this purpose, the square wave voltammetry (SWV) technique was used. It should be noted that the use of other techniques such as differential pulse voltammetry, cyclic voltammetry, stripping voltammetry, adsorptive stripping voltammetry, among others, can also be used to obtain a screening method for natural gas prospecting.

[30] Voltammetric screening is based on identifying oxidation and / or reduction peaks at specific potentials presented in each sample. By comparing these potentials, it is possible to identify the profile of each sample and distinguish them from each other, either by identifying peaks with exclusive characterization, or by differentiating the voltammetric profile of the samples. The criterion used to identify a given sample is called the diagnostic criterion. Petition 870250013816, dated 20 / 02 / 2025, page 19 / 38 / 15

[31] To obtain the diagnostic criterion for the presence of natural gas in sediment samples, marine sediment samples collected at three distinct sampling sites were compared. The first point did not contain mud volcanoes and was designated as background. The second point was a region containing a mud volcano that was actively expelling fluids. This point was designated as the active plume and is the main point of interest for natural gas prospecting, since the expelled fluid has natural gas in its composition (mainly methane, but also containing ethane, propane, nitrogen gas and carbon dioxide). The third point was in a region containing a mud volcano that is not expelling fluid, and was identified as the inactive plume. The proposed method for natural gas prospecting is not limited to the samples described above, and can be applied to any sediment sample.

[32] The voltammetric screening method for natural gas prospecting was carried out as follows: (i) fabrication of the carbon paste electrode modified with sediment, (ii) obtaining the electrochemical profile of the samples; (iii) interpretation of the voltammograms obtained; (iv) mapping of the characteristic peaks of the samples; and (v) definition of the diagnostic criteria for identifying the presence of gas in the studied region.

[33] In this way, the method proposed in this patent represents an innovation in the area of ​​natural gas prospecting, since VIMP analyses are cheaper than the analyses currently used and allow analyses to be carried out directly in the solid state. Example of implementing the invention

[34] The present invention describes a method for preparing a carbon paste electrode modified with sediment, in order to be used for natural gas prospecting. For this purpose, the sediment samples must be lyophilized for 42 hours, followed by maceration in a mortar and pestle for 5 minutes for homogenization. Subsequently, 0.2 g of the sample of Petition 870250013816, dated 20 / 02 / 2025, page 20 / 38 / 15 lyophilized sediment must be macerated in a mortar and pestle together with 0.6 g of conductive material (carbon black) and 0.2 g of binder (mineral oil) for 40 minutes. This paste must then be packed in a container using a copper wire as an electrical contact to finalize the electrode preparation. It should be noted that one paste must be prepared for each sample to be analyzed.

[35] The analyses must be performed in a voltammetric cell composed of a three-electrode system, using the sediment-modified carbon paste electrode as the working electrode, the Ag / AgCl (3 mol L-1 KCl) electrode as the reference, the platinum electrode as the auxiliary electrode, and 0.1 mol L-1 NaOH as the supporting electrolyte. The diagnostic criterion for identifying sediment samples collected in regions containing natural gas (active plume) was defined by SWV with the parameters of 3 mV, amplitude of 25 mV, and frequency of 5 Hz, in anodic scans from -1.2 to 1.5 V and cathodic scans from 1.5 to -1.2 V.

[36] Obtaining the diagnostic criterion for natural gas prospecting in solid-state sediment samples was carried out by identifying unique characterization peaks in anodic and cathodic voltammograms. In other words, oxidation and reduction peaks were identified that are unique to the electrochemical profile of a marine sediment sample collected in a region that contained natural gas (active plume).

[37] Regarding the obtained profiles, the anodic and cathodic voltammograms complemented each other, where in the anodic scan, it was possible to identify an exclusive oxidation peak (potential of 0.22 V) of the sediment sample collected in the region containing an active plume mud volcano (region containing natural gas). Confirmation was performed in cathodic scanning, identifying a reduction peak at a potential of 0.77 V. Once these two peaks were identified, it can be stated that there is natural gas in the region where the sediment samples were collected. Petition 870250013816, dated 20 / 02 / 2025, page 21 / 38 / 15

[38] It is worth noting that the experimental conditions, such as the method of immobilizing the sediment sample on the working electrode, as well as the electrolyte and the SWV technique with their respective parameters, may be altered, since all these parameters can be optimized, making the natural gas prospecting process more efficient. In this way, a new combination of experimental conditions may present a better response when applied in conjunction with the proposed voltammetric screening method. Bibliographic References

[39] Carvalho, AB Ocean Economy: concept, value and importance for Brazil. Thesis (Doctorate) - Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, 2018.

[40] Castro, BM et al. The Blue Amazon: resources and preservation. Revista USP, n. 113, p. 7-26, 2017.

[41] Doménech-Carbó, A. et al. Electrochemistry-based chemotaxonomy in plants using the voltammetry of microparticles methodology. New Journal of Chemistry, 39, 7421-7428, 2015.

[42] Doménech-Carbó, A. et al. Layer-by-layer identification of copper alteration products in metallic works of art using the voltammetry of microparticles. Analytica Chimica Acta, v. 680, p. 1-9, 2010.

[43] Fiedler, DA, Scholz, F. In: Electroanalytical Methods: Guide to Experiments and Applications, 2005.

[44] Gardioli, HFG et al. Integration of geological, geochemical and geophysical data used in hydrocarbon prospecting. Rev. Ambiente Acadêmico, v.1, n.2, p. 22-41, 2015.

[45] Gutierrez, MBGPS The natural gas sector in Brazil: A comparison with OECD countries (No. 2777), 2022. Petition 870250013816, dated 20 / 02 / 2025, page 22 / 38 / 15

[46] Ijiri, A. et al. Origins of sediments and fluids in submarine mud volcanoes off Tanegashima Island, northern Ryukyu Trench, Japan. Frontiers in Earth Science, 2023.

[47] Kurniawan, Y. S. et al. Science and Technology Progress on the Desulfurization Process of Crude Oil. Bulletin of the Korean Chemical Society, v.42, n.8, p. 1066-1081,2021.

[48] Mazzini, A., Etiope, G. Mud volcanism: An updated review. Earth-Science Reviews, v. 168, p. 81-112, 2017.

[49] Reis, H. L., Pedrosa-Soares, A. C., Voll, E., & Cunha, E. C. Gás natural. Recursos minerais de Minas Gerais. Companhia de Desenvolvimento de Minas Gerais (CODEMGE), Belo Horizonte, p. 1-39, 2018.

[50] Scholz, F. Electroanalytical methods: guide to experiments and applications. Berlin: Springer, 2005.

[51] Scholz, F., Schrode, U., Gulaboski, R. Electrochemistry of immobilized particles and droplets. Berlin: Springer, 2015.

[52] Silveira, GD et al. Evaluation of aging processes of petroleum asphalt cements by solid state electrochemical monitoring. Electrochimica Acta, v.270, n.20, p. 461-470, 2018.

[53] Souza, MO et al. Exploratory analysis of the concentrations of metals Na, Ca, Mg, Sr and Fe in aqueous petroleum extract, determined by ICP OES, after optimization using experimental design. Quim. Nova, v. 38, n. 7, p. 980-986, 2015.

[54] Speight, JG Natural gas: a basic handbook. Gulf Professional Publishing, 2018.

[55] Sun, Q. et al. Seismic vibration for improved oil recovery: A comprehensive review of literature. International Journal of Hydrogen Energy, v.45, p. 1475614778, 2020.

[56] Widmann, A. et al. Structure, Insertion Electrochemistry, and Magnetic Properties of a New Type of Substitutional Solid Solutions of Copper, Nickel, and Petition 870250013816, dated 20 / 02 / 2025, page 23 / 38 / 15 Iron Hexacyanoferrates / Hexacyanocobaltates. Inorganic Chemistry, vol. 41, no. 22, p. 5706-5715, 2002. Petition 870250013816, dated 20 / 02 / 2025, page 24 / 38

Claims

1 / 2 CLAIMS 1) PROCESS FOR PROSPECTING FOR NATURAL GAS IN MARINE SEDIMENTS USING IMMOBILIZED MICROPARTICLE VOLTAMETRY is characterized by a process for prospecting for natural gas in marine sediments using voltammetry of immobilized microparticles (VIMP), from the following steps: (a) obtaining the carbon paste electrode modified with sediment; (b) use of a voltammetric cell containing a modified carbon paste electrode as the working electrode, Ag / AgCl in 3 mol L-1 KCl as the reference electrode, a platinum electrode as the auxiliary electrode and 0.1 mol L-1 NaOH as the supporting electrolyte; (c) use of the square wave voltammetry technique to obtain the electrochemical profile of the samples; (d) interpretation of the voltammograms obtained and definition of the diagnostic criteria for identifying the presence of natural gas. 2) PROCESS FOR NATURAL GAS PROSPECTING according to claim 1, characterized by using carbon black as a carbonaceous material in the preparation of a paste electrode, in an amount equivalent to 60%, in addition to the use of lyophilized sediment sample as a modifier and mineral oil as a binder, each in a proportion of 20%. 3) PROCESS FOR NATURAL GAS PROSPECTING according to claim 1, characterized by using marine sediment samples for natural gas prospecting. Petition 870250013816, dated 20 / 02 / 2025, p. 25 / 38 2 / 2 4) PROCESS FOR PROSPECTING FOR NATURAL GAS according to claim 1, characterized by using the square wave voltammetry technique to obtain electrochemical profiles, with a potential step of 3 mV, amplitude of 25 mV and frequency of 5 Hz, in anodic sweeps from -1.2 to 1.5 V and cathodic sweeps from 1.5 to -1.2 V. 5) PROCESS FOR NATURAL GAS PROSPECTING according to claim 1, characterized by the analysis of sediment from a region containing an active plume mud volcano and the identification of an oxidation peak at a potential of 0.22 V (in anodic scanning) and a reduction peak at a potential of 0.77 V (in cathodic scanning), thus characterizing a region containing natural gas. Petition 870250013816, dated 20 / 02 / 2025, pp. 26 / 38

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