The changing of oil hydrocarbon in the reservoirs with the course of time

One of the important problems in oil geology and oil geochemistry is research of origin organic agents, oil formation and regularity of its changing in the well. In this article is viewed the oil hydrocarbons changing during the time. The brought data is the result of 10 years experimental observes. The experimental survey was conducted on apparatus (ARNS-1E) according to gradual evaporation method by GOST 1392-82. For this experiment were selected 5 deep wells of VII horizon in Bulla-deniz field. With the aim of more accurate identification of oil hydrocarbons geochemical changing during the time the samples were selected with the period from 3 to 11 years, i.e. have been applied different variants of time limitation in sample selection (wells 70, 106, 11 and 73). Besides, we have reviewed the influence of occurrence depth on oil hydrocarbons transformation. For the experiment have been selected samples from the wells 149 (2768 m) and 238 (4437 m). In spite of more than sufficient difference in occurrence depths the light fraction from the well 149 was 90% and from the well 238, despite the large depth, the light fraction from the initial boiling point (IBP) - 1500 C was 10%. As it is obvious the charge from the light fractions in the samples selected from the different depths of above-mentioned wells testifies the degree of depth influence on hydrocarbons changing in the deposits. The conclusions are as follows: 1. In studied oils with the time passage any changes in the deposits have not been observed 2. It has been identified that depth factor has not influence on oil hydrocarbons changing 3. It has been determined that reliable results may be obtained in selective geochemical research 4. Correlation fraction IBP-150С / fraction 150С EBP (ending boiling point) showed that reviewed oil hydrocarbons are the high changed