SU1004942A1 - Method of geochemical locating of oil and gas deposits - Google Patents

Description

(S) METHOD OF GEOCHEMICAL SEARCHES FOR OIL AND BASIN DEPOSITS

The invention relates to geological exploration and can be used in the search for oil and gas accumulations in areas of distribution of salt-bearing sediments that are widely developed in oil and gas bearing regions.

There is a method of searching for oil and gas deposits in areas of low permeability intrusive traps, including drilling wells to open trap intrusions, sampling dolerites, degassing them, analyzing gas, studying porosity and fracturing, comparing with similar parameters of reference areas, which makes it possible to identify sectional epigenetic hydrocarbons t1.

However, this method for salt-bearing deposits does not provide sufficient reliability of prospecting works due to the peculiarities of the geo-hygienic structure of the salt-bearing section and the limited flow of hydrocarbons.

The closest in technical essence and the achieved result to the invention is a method of geochemical exploration of oil and gas deposits including drilling of wells, selection of a representative horizon, selection of 5 samples of rocks, their degassing by thermal vacuum and mechanical methods, gas analysis for hydrocarbon components and gels, determination

to dispersed organic carbon, an analysis of the consistency of the distribution of these parameters in a representative horizon, a conclusion from these data about the prospects for the oil and gas content of the structures 2.

However, this method is inefficient and time consuming when searching for oil 20 and gas in areas of distribution

Claims (2)

salt-bearing deposits due to the complexity and limited diffusion-filtration transport of hydrocarbons in these deposits. The purpose of the invention is the acceleration and cheapening of work, 9 areas of development of powerful salt tires. The goal is achieved by the fact that according to the method of geochemical. prospecting of oil and gas fields, including sampling of rocks in wells, their chemical degassing, analysis of the extracted gas for methane content of its homologues, determination of organic carbon in samples, comparison of the hydrocarbon content of rocks of the studied and reference areas, and judgment of perspectivity To carry out the test object, rock samples are taken from the sediments lying above the salt-bearing tires, the magnesium-containing carbonaceous rocks are extracted from them, and the gas extracted from this part is analyzed. aztsa The method is based on the following positions. Saline deposits and the over-salt deposits directly above them. The deposits are characterized by an abundance of distribution of not only Halite, but also carbonate rocks — calcite and dolomite. The data on the distribution of hydrocarbon gases in productive and unproductive areas in the areas of distribution of salt deposits showed that the latter are not an absolute screen and have conductive properties with respect to migrating gaseous and vaporous hydrocarbons. The inclusion of impurities of terrigenous-carbonate material, micro- and macrocracks, active tectonics contributes to this process. In addition, carbonate rocks, especially dolomites, have the ability to concentrate hydrocarbons from a migration stream of gases containing them in small quantities. Studies have shown that salts have selective shielding properties, which manifest a partial delay in the migration flow, mainly homologues of methane and especially vaporous methane hydrocarbons (N. higher and aromatic hydrocarbons), and their relative accumulation in the lower parts of the section. leads to a legitimate change in various gas-geochemical indicators for the section. When comparing productive and non-productive areas, the concentration of gas 10 942 homologues of methane and sulfur Molar content of hydrocarbons in salts and carbonate rocks has the greatest contrast. Sharing data on salt and over-salt rocks has the greatest effect. The method is implemented as follows. rock-containing carbonates, such as dolomites, are extracted from them and dolomite samples are subjected to two-step degassing followed by a thermal method at C and chemical decomposition. hydrochloric acid. They determine the impurities of terrigenous material and organic carbon. All gases extracted from dolomite are analyzed for the content of individual methane hydrocarbons up to and including C and -C aromatic hydrocarbons, determine the nature of the distribution of hydrocarbons in the section, the ratios between the individual components, their connection with the organic hydrogen, compare data with similar indicators on this-, lnnyh areas x. All this allows em. reveal, in the context, the presence of epigenetic (migration) hydrocarbon gases, based on the anomalous values of which judge the prospects of the studied section for oil and gas. The use of the proposed method allows to increase the degree of reliability of assessing the prospects for the oil and gas potential of local areas in areas of distribution of salt-bearing sediments, as well as to improve the performance of geochemical studies by reducing the volume of deep exploratory and exploration drilling. The invention method of geochemical prospecting of oil and gas fields, including sampling of rocks in wells, their chemical degassing, analysis of the extracted gas for methane content and its homologues, determination of organic carbon content in samples, comparison of the hydrocarbon content of the rocks of the studied and reference areas 5,126 spares and judgment of prospecting of research- Sources of information, the object being blown, which is taken into account when examining with the aim of speeding up and cheapening of work in areas of high-powered development t. USSR author's certificate of salt-carrying tires, samples of rocks of the Vf 2786836 / 18-25 application, are taken from sediments lying down. G 01 V 9/00, 1979. over salt caps, are recovered 2. Methodical recommendations But from them the magnesium-containing carbonate geochemical methods of searching for local rocks and analyzing the gas, extracted oil and gas, are produced by this department from this part of the sample. toM., 1975. her. 83, 159 (prototype).