CCS Technologies: from theory to practice

DOI: 10.24412/2076-6785-2023-8-107-110

In 2015, a Paris Climate Agreement was signed, one of the main goals of which is to “Ensure healthy lives and promote well-being at all ages”. To achieve this goal, the greenhouse gas emissions will be reduced down to 70 % of the 1990 level. The Agreement has also been signed by the Russian Federation, which ranks third in terms of emissions out of 192 parties to the agreement.
At the St. Petersburg Economic Forum in 2022, President of the Russian Federation Vladimir Putin said: “We will generally develop clean technologies in order to achieve the goals set for the environmental modernization of enterprises and to reduce harmful emissions into the atmosphere, especially in large industrial centers. We will also continue to work within closed-loop economy projects as well as climate conservation and green projects.”
Taking into account the global trends and long-term plans of the Russian Federation, “NK “Rosneft” PJSC has set a goal to achieve carbon neutrality by 2050. This will be achieved through emissions reduction measures, low-carbon generation, the development of energy-saving technologies, carbon capture and storage technologies, utilization of natural absorption potential, as well as a number of other technologies.
In terms of the methods of handling CO2 emissions, oil companies distinguish two promising areas: Carbon Capture and Storage (CCS) technologies which cover separating carbon dioxide from other gases in industrial emissions (usually at gas turbine power plants or APG flares) followed by compression and transportation to an isolated place for long-term storage, and Carbon Capture Utilization and Storage (CCUS) technologies which also cover the separation of carbon dioxide from other gases, but for further useful utilization, in particular, to enhance oil recovery (EOR). Currently, a feasibility study on the application of CCS/CCUS technologies in the pilot subsurface areas of “NK “Rosneft” PJSC has been launched.
In the CCS domain, criteria have been formed to organize the storage of CO2 in natural reservoirs. The geological targets promising for long-term storage are being searched and ranked within the pilot sites. Porous aquifers suitable for long-term storage of carbon dioxide, requiring only the construction of wells and organization of injection process, are being analyzed as the main locations. The analysis of geological data allowed to develop the basic principles of selecting the storage targets: the presence of a trap, a shale seal, a sufficient volume of pores and permeabilities sufficient for injection. The analysis involved tools similar to those used to search for oil traps: seismic studies, petrophysical, hydrogeological and geomechanical data. The final stage of the work is geological modeling and flow simulation which allows us to determine with high accuracy the potential of storing carbon dioxide in porous aquifers, as well as to assess the gas migration potential in the longer term.
In the CCUS domain, the EOR performance of injecting carbon dioxide into an oil reservoir is being assessed. To select the technology, a sequence of actions has been developed with the following stages: build an Equation of State (EOS) to determine the minimum miscibility pressure (MMP), select reservoirs suitable for miscible conditions, run laboratory studies on fluid and core samples, build composite dynamic models to evaluate process parameters, and select process equipment for injection. The computations will form the basis for a feasibility study of CO2 injection performance and will allow to determine the geological criteria of applicability and to develop standard solutions for process equipment.

Materials and methods
Approaches have been formed to justify the choice and evaluation of candidate reservoirs for CO2 storage.


Keywords
Сarbon Capture and Storage (CCS), Carbon Capture Utilization and Storage (CCUS), geological storage of CO2, gas-enhanced EOR, modeling of CO2 geological storage, modeling of gas-enhanced EOR, decarbonization