Technology-related metamorphism of the Cenomanian waters on the example of Urengoy oil and gas condensate field

All environmental waters of Yamalo- Nenets oil and gas production region, including Cenomanian waters are affected by man-induced impact. Alteration of hydrogeological conditions, transformation of the chemical composition of subsurface watersand formation of technology-related hydrogeological systems are caused by the influence of technogenesis.The results of surveys of man-induced metamorphism of the Cenomanian waters at the sites of sewage waters injection are provided in the paper.
Materials and methods
The results of more than 2500 fluid samples taken from the exploration, pressureobservation, monitoring, injection and operations wells within the period from 1987 till 2014 are used. The survey results are analyzed and handled with the method of mathematical statistics.
Results
The author analyzed hydro-chemical characteristics of sewage waters, gave average compositions for all the sites of water injection and assessed the degree of man-made impact on the Cenomanian waters at the sewagewater injection sites by making variation series for various time intervals. There was calculated the area of contamination ofthe Cenomanian waters as of 2006 andfor 2026. The author made assessment of metamorphization of the Cenomanian waters at the injection sites.
Сonclusions
As a result of sewage waters injection at the sites of Urengoy oil and gas condensate field there took place not only dilution of salt Cenomanian waters tothe light-salt but also irreversible change of the chemical composition called technology-related metamorphism. The conclusion is proved by the assessment of the degree of metamorphization ofthe Cenomanian waters at the injection sites with two assay procedures and were showed an examples chemical analysis Senomanian waters.