Оптимальный метод определения водосодержания нефтегазоматеринских пород баженовской свиты Западной Сибиристатья
Статья опубликована в журнале из списка RSCI Web of Science
Информация о цитировании статьи получена из
Scopus
Статья опубликована в журнале из перечня ВАК
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 20 декабря 2019 г.
Аннотация:Hydrocarbon resource assessment and estimation oil and gas reserves source-rock reservoirs within the Bazhenov formation of Western Siberia require a comprehensive study of their water content. So far, the petrole- um industry has been using known laboratory methods for direct deter- mination of water content for low-permeable shale Bazhenov formation rocks. However, the question of data validity and quality remains open since the legacy methods have been developed for conventional reser- voirs. The article presents a new laboratory method for measuring the water content, explicitly designed for shale rocks with initially low water content (less than 5% wt.). The proposed evaporation method allows de- termining the amount of free and physically bound water in rock samples with a mass of 25-70 g within 1-3 h. The error in determining the mass water content for in evaporation method depends on the initial water content and is 0.2-6.8% wt.
Testing of the evaporation method included a target collection of whole core samples with the maximum preserved natural water con- tent, taken from five wells of various fields within the Bazhenov forma- tion interval. The study reveals the temperature ranges for extracting free (121°C) and physically bound water (250°C). The measured water content of the Bazhenov formation rocks samples is 0.28-4.27 wt.% with the free water content from 0.04 to 2.53% wt. Water content decreas- es in carbonate interlayers and increases in the clay-rich units. We ex- perimentally studied the effect of storage conditions and sample size on the results of water content determination. We also established that reliable water content data requires fragmenting a core sample into pieces with specific dimensions of at least 5-7 cm immediately after opening the protective shell. Comparison of water content data ob- tained using the Dean – Stark method and the evaporation method showed that the latter delivers much more accurate results for the oil and gas source Bazhenov formation.