SU1287084A1 - Method of geochemical searching for oil and gas deposits - Google Patents

Abstract

The invention relates to the field of oil and gas geology, for example, to search for oil and gas fields and can also be used in geological mapping. The purpose of the invention is the sensitivity and reliability of the method in the areas of development of alu-al-clad deposits. For this, a sample is taken from a sandy subsoil horizon. The granulometric fraction of them is less than 0.05 mm. It is analyzed for copper content and the presence of an oil and gas field is judged by the anomalous values of this parameter. 1 tab. ABOUT)

Description

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The invention relates to oil and gas geology, is aimed at searching for oil and gas fields, and can also be used in geological mapping.

The purpose of the invention is to increase the sensitivity and reliability of the method in the areas of distribution of alluvial deposits,

The method is carried out as follows.

Within the limits of the prospecting site, samples of sandy subsoil horizons (alluvial sediments) are selected, and a particle size fraction of less than 0.05 mm is isolated from them. The output fraction is determined, for example, by the spectral emission method, the copper content. According to the anomalous values of the copper content in the granulometric fraction — less than 0.05 mm of windows — oil and gas deposits are drilled,

For example, the Method was tested in the southeastern part of the Dnieper-Donets Basin at gas fields and anticlinal structures that do not contain gas that are geologically close to each other. At the Spivakovsky and Ol'khovskoye gas fields, covered with alluvial deposits, sand samples from the subterranean horizon were taken from the area, from which a fraction less than 0.05 mm was extracted, the copper content was determined by spectral emission analysis in the obtained fraction. The average copper content in gras, —nomotric fraction less than mm of subsoil sediments of some structures of the southeastern part of the Dnieper-Donets depression (n,) is presented in the table.

For comparison, the Krasnoskolsk structure, which does not have a gas reservoir and was blocked by alluvial deposits, was tested in a similar way. All the above mentioned structures are characterized by a high ground level.

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tovov waters (4-6 and). For comparison, structures with non-alluvial deposits, deluvial loams, and having a low level of ground water (more than 20 m) are also tested: Veliko-Kamyshevakhsk is a non-gas-bearing structure and the Shebelinsky gas field.

As can be seen from the example, the average copper content in the subsurface, alluvial horizon, overlapping gas fields is 4 ,, whereas outside the fields they are 1.8-2.6 Yu%, the contrast ratio (QC) is the ratio of the average content copper over the structure to its content outside the structure — for gas fields covered by alluvial deposits is 1.76-2.54 (2 average), while for similar rocks crossing the structure without a deposit it is 0 ,9,

The average copper content in the subsurface horizon of structures covered with deluvial loams, regardless of the presence of gas and position relative to the structure, is 2f7-2.8 10% with a contrast ratio of 1.01-1.04,

Claims (1)

Invention Formula The method of geochemical prospecting of oil and gas fields, including sampling of subsurface sediments, their separation into granulometric fractions, physical and chemical analysis of the latter for copper content and judgment on its abnormal content of the presence of the deposit, o tl and h ay Since, in order to increase the sensitivity and reliability of the method, in the areas of distribution of alluvial deposits, samples are taken from sandy deposits, and the copper content is determined in the α-granulometric fraction less than 0.05 mm. Above structure Outside the structure Contrast Ratio (QC) 200.82 314.64 16 4.59 342.84 262.75 360.85 341.82 20 2.60 J62.73 242.72 0.9 2.54 1.76 1.04 1.01 1.76 1.04 1.01