GAS-CONDENSATE STUDIES OF WELLS AT FIELDS WITH ABNORMALLY LOW RESERVOIR TEMPERATURE

The article considers the influence of anomalous thermobaric conditions of reservoir systems of Western Yakutia fields on the quality and reliability of the results of gas-condensate studies (GCS) of wells. This group includes almost all fields of the mentioned region and first of all Chayandinskoye, Srednebotuobinskoye, Verkhne-Vilyuchanskoye, Talakanskoye and other oil and gas and condensate fields. The factors that have a significant negative effect on the determination of calculation values of reservoir gas composition and potential condensate content in it were identified. In this connection, the necessity of making corrections and additions to the existing methods of GCS is shown. The gas-dynamic and thermodynamic sequence of influence of anomalously low formation temperature on the parameters of formation gas separation process during field studies is determined. Materials of gas-condensate wells researches on deposits of Western Yakutia for previous periods with indication of methodical and technical deviations of the given results concerning finally accepted at their defense in the State Commission on Reserves of Mineral Resources are resulted. The methodology of GCS with formation gas heating at the inlet to the separation unit is described in detail. The description of constructive solutions and the list of necessary materials for realization of the process of well investigation with inlet gas heating are given. The results that have been recently obtained during the behavior of well GCS data at the Otradninskoye gas and condensate field using the technological additions proposed and outlined in this article are presented. A visual table of the effect of formation gas heating at the separator inlet on the condensate-gas factor and crude condensate shrinkage factor was compiled, and the volumes of degassing and debutanization gases of crude condensate were determined. The overall results of GCS, after chromatographic analyses, are shown in a comparative table, where the composition and content of condensates (C5+higher) were calculated, densities were measured and condensate initial and end boiling temperatures were determined depending on the well investigation mode. The efficiency of using the heat exchanger was confirmed in order to achieve optimal temperature conditions for gas separation and to achieve stable and complete separation of the initial gas mixture with a more stable phase ratio (gas-condensate).