Patent ID: 6271518
Filing Date: 2001-08-07
Classification: G01N

Abstract:
Process for detecting and characterizing formation hydrocarbons which comprises carrying out the following steps:taking a sample of material which is representative of the rocks passed through during a drilling operation,taking a determined amount of material to be analysed from the said sample of material,extracting the hydrocarbons contained in the said amount of material to be analysed, using cyclohexane, in order to make up an initial extract,wherein said process further comprises carrying out the following operations:diluting the initial extract by a factor d in order to obtain a final extract,exciting the final extract with ultraviolet radiation of a wavelength chosen within the band substantially between 250 and 400 nanometers,recording, in a wavelength band L, an emission spectrum resulting from the excitation of the final extract,calculating the emission flux of the sample of material by applying the following formula: ##EQU8##in whichFLUX represents the emission flux of the sample of materialI(.lambda.i) represents the intensity of the radiation emitted at a wavelength .lambda.i of the band L by the final extract,n represents the number of wavelengths of the emission spectrum sampled at a pitch of between 1 and 20 nanometers, and is equal to L divided by the pitch,i ranges from 1 to n,the value of the emission flux of the sample of material is proportional to the concentration of fluorescent elements in the sample of material,calculating the fluorescence quotient of the sample of material using the following formula:FQ=area A/area Bin which:FQ represents the fluorescence quotient of the sample of material, area A and area B are calculated, respectively, by the following formulae: ##EQU9##in which:I(.lambda.i) and n are defined as above,x is an integer between 1 and n,the value of the fluorescence quotient of the sample of material is representative of the nature of the hydrocarbons contained in the sample of material.