METHOD DETERMINING NATURE ON INTERSTRING GAS MANIFESTATIONS AT STAGE OF DRILLING AND LAYING UP OF GAS WELLS OF MULTIPOOL DEPOSIT BY GEOCHEMICAL PROCESSES

commercial geology. SUBSTANCE: method can be used at stages of prospecting, development and usage of multipool gas and gas condensate deposits when there emerges necessity of determination of nature of hydrocarbon gases getting into interstring space. Standard section with allocated and characterized gas-saturated horizons is formed in area of deposit in agreement with geochemical method of determination of nature of interstring gas manifestations. Composition of hydrocarbons including isotopic composition of methane carbon of allocated gas-bearing horizons is distinguished. Beneficiation of gas composition with heavy hydrocarbons and of methane with heavy isotope with growth of depth of gas generation takes place in consequence of vertical zonality of processes of oil and gas formation. Gas-bearing interval from which gas manifestation originates during drilling, operation, laying up of wells is exposed by method of interstring sampling of gases, their quantitative and qualitative composition, correlation of their composition with standard gas-chemical section are determined by chromatographic analysis. In this case object of search is not location of defect of operational string as in geophysical methods but gas-bearing horizon proper from which hydrocarbons migrate that exposes in the long run interval of leaks. EFFECT: reduced cost and shortened time to make decision on repair operations, improved authenticity of method of determination of isotopic composition of methane carbon. 3 dwg