Место издания:Schweizerbart Science Publishers Stuttgart, Germany
Первая страница:127
Последняя страница:128
Аннотация:The study of organic matter (OM) in oil and gas basins brings a lot of new, and sometimes unexpected information, that creates , fortunately at the time, some of the problems. It is inevitable, because our research follows exploration into new uncharted regions descend on unattainable before depth and meet the objects out of attention earlier.
It is well known to specialists involved in organic petrology that agreement in macerals’ names has not only terminology value. In our work we use such terms as " amorphous OM", "solid bitumen", "bituminite", "proto-, post-mature OM", which, in fact, belong to the same macerals. This inherently sapropelic OM previously referred to alginite of different types. Different transformation rank, sizes, forms find the breed resulted in a great variety of macerals, which came to be called differently. Fortunately, the efforts of our highly respected petrologists in overcoming this problem, had success! This year's publication "Classification of liptinite-ICCP System 1994" will contribute to the maintenance of our new terminology and facilitate references.
Conversion of macerals’ reflection (RM,%) to RV,% and use it as equivalent is the second problem we often meet in our practice. Convergence of both deviations – nomenclature and estimation, shows itself in our work. We’ve already used to involve in reflectance measurements such macerals as bituminite, graptolites, chitinozoa, etc. (Hartkopf-Fröder et al., 2015). The works by Jacob H. (1985), Lui, D.H. et al.(1994) and others are very useful, they make suggestions for RVeq,% calculation through RB,% (bituminite or another). The role of proper maceral name is important here, as different coefficients can be used for different macerals.
As an example, studies of OM in the Jurassic sediments of one of the northern regions of West Siberian basin can be demonstrated. In samples studied from the depth of 2500-3000m, a high content of OM was found (not less than 15-20%). The most common organic macerals were bituminites and "bitumens" associated with them (fig.1). Bituminites include discharges of amorphous OM with not straight, dissolving contours. Bituminites occur in the form of stringers, lens, lenticular beds, and also in the form of clots, lumps filling space between mineral grains. In white reflected light the color of the maceral is gray. The sizes of bituminites are very different from 2-3 microns to 0.1 mm and more. The length of lens,stringers can exceed 30-50 mm. The term "bitumens" is used for films, raids and clots of brown color. Organic matter of "bitumens" undoubtedly was liquid and mobile. The connection of bitumens and their initial macerals – bituminite, is obvious. Coexistence of bitumen and bituminite in source rocks not only proves their genetic connection, but can also be considered as a sign of the beginning of oil generation (or some other phase). Some of the fluorescent properties of liptinite macerals can also be regarded as indicative features of the oil formation process.