Geochemical Monitoring of Formation Fluids for Reservoir Management Considering Complicating Factors in Mature Oilfields

At the present stage of the hydrocarbon production process, most of the unique and largest fields in the world are at a late stage of development. Despite the active development and policy of a decarbonised economy, the demand for liquid and gaseous hydrocarbons remains high, while of inevitably growing the number of mature fields. The Volga-Ural oil and gas province today is an old oil and gas producing region, most of the fields have already entered the final stage of development. However, through the introduction and development of new technologies for oil extraction, monitoring of production and localization of reserves, the life of the fields can be extended. One of these technologies is geochemical monitoring of well production. Its goal is to optimize the development of mature fields on the basis of promptly obtained information about the state of the wells using geochemical studies of the formation fluid, allowing timely implementation of the necessary measures. Geochemical studies allow identifying the source of fluid entering the well, determining a violation in the wellbore structure, checking the tightness of downhole equipment for separate operation, and performing an area analysis of the area development efficiency. This type of research is relevant both in giant fields with a large stock of production wells, often characterized from a geological point of view by multilayer structure, with technological complexity, packing, wear of equipment and strings, in some cases the impossibility of running gauge for research, and in fields with low depletion. The possibilities of geochemistry for solving local operational problems in wells are shown. Several hydrogeological complexes have been studied, the change in the properties of the produced water during the development process is described. The concepts of the geochemical conditions in the hydrocarbon deposits that existed earlier are changing due to the development of these objects as a dynamic system, continuous injection of different types of water into the reservoir, the use of enhanced oil recovery methods and other technogenic impact associated with the development of reserves. The digital revolution and the modern development of the industry marked the beginning of the creation of the Digital Atlas of Groundwater, the development of specialized algorithms that allow processing large amounts of data.