SU1030754A1 - Geochemical method of oil and gas deposits location - Google Patents

Abstract

GEOCHEMICAL METHOD OF SEARCHING FOR OIL AND GAS DEPOSITS, including sampling porol of low-permeable formations in contact with the reservoir, their analysis of barium content and judgment based on the obtained data on the presence of the field, differing from the fact that, in order to improve the accuracy of searches, in samples it is determined the content of cerium and neodymium, calculate the ratio of the difference between the content of cerium and neodymium to the content of barium, and the conclusion about the presence of a deposit is made when the ratio of this ratio exceeds 0.5. (About SL SG1;

Description

This invention relates to methods for searching for oil and gas, based on: an element analysis of rock samples.

A geochemical method is known for oil and gas fields, which involves collecting samples of the subsoil layer and core or sludge while drilling wells and analyzing the content of the acid forms of metals, such as ferrous iron, and the presence of deposits is abnormal. ..С11.

The disadvantage of this method is its low reliability, since in some conditions, ferrous iron anomalously concentrates the communication link with the oil field H of gas,

The closest to the invention to the technical essence is the method of searching for oil and gas,. based on the analysis of samples of low-permeable rock - tires for barium content and some other elements and judgment on the data obtained about the presence of the deposit 23.

The disadvantage of the known method is that it does not provide direct information about the productivity of the studied part of the section, only to draw conclusions about the conditions of sedimentation and the direction of exploration;

; The aim of the invention is to increase the reliability of searches.

This goal is achieved by the fact that, according to the geochemical method of exploration of oil and gas fields. Providing for the sampling of rocks of low-permeable formations in contact with the reservoir, their analysis. The content of barium and judgment are based on the obtained data on the presence of the deposit, the samples are additionally determined for the content of cerium and neodymium, the ratio of the difference between the content of cerium and neodymium to the content of barium is calculated, and the conclusion about the presence of a deposit is made at a value of this ratio greater than 0.5.

The method is based on the fact that the interrelation of geochemical processes in a hydrocarbon-containing medium and rocks in contact with it determines the relation of the elemental composition of such rocks or the ratio of the concentrations of certain elements in them to oil and gas saturation.

The method is carried out as follows.

Samples of clays in contact with the collectors are taken, the nature of saturation of which is to be determined. Samples weighing 20-30 g are analyzed for the content of barium, cerium and neodymium by X-ray radiometric method. With the americium-241 source, the instrumental complex includes a BDRK-1-25 silicon-lithium detector SES2-03 spectrometric unit and an LP-4840 800-channel analyzer.

The concentration of indicato elements is determined from the instruments of the Covell method. As a diagnostic indicator, use the parameter

X:

5 where C, Cj, Cj are cerium concentrations,

neodymium and bari respectively.

If its value exceeds the value of O, 5 (The collector is considered productive.

Using the proposed method provides effective information when solving the most important tasks of oilfield geophysics - determining the nature of saturation of the studied formation.

Claims (2)

GEOCHEMICAL METHOD FOR SEARCHING OIL AND GAS DEPOSITS, including sampling rocks of low-permeable formations in contact with the reservoir, analyzing them for barium content and judging by the data on the presence of a field, which is characterized by the fact that, in order to increase the reliability of searches, the samples additionally determine the content cerium and neodymium, the ratio of the difference in the content of cerium and neodymium to the barium content is calculated, and the conclusion about the presence of a deposit is made when the value of this ratio exceeds 0.5. , -. <2 ω with fe X SI 4 ^