Multiphysical Numerical Simulation of CO2-EOR Processes

  • Date: –12:00
  • Location: Geocentrum Luftrummet
  • Lecturer: Prof. Yu-Shu Wu (Colorado School of Mines, USA)
  • Organiser: Inst. för geovetenskaper
  • Contact person: prof. Auli Niemi
  • Seminarium

CO2-EOR has surpassed thermal recovery methods now and becomes #1 approach in EOR operations in the US currently. Typical incremental oil recovery by CO2 IOR/EOR is 5~25 %  and about 93% of the CO2-EOR projects in the world have been carried out in the U.S., which contribute to 5% total US oil production. CO2-EOR in the US has steadily increased (~134 projects), but its growth in application has slowed down in the past few years, and this slowdown is primarily due to accessible and affordable CO2 sources. CO2 flooding has been receiving greater attentions due to its effectiveness and capability to increase oil recovery rate from tight oil or low-permeability reservoirs. The US experiences in developing tight oil reservoirs in the past decade has shown that gas injection, such as CO2 or natural gas flooding or huff-n-puff, is the only approach that works for enhancing oil recovery from low-permeability unconventional tight-oil reservoirs. Considering the large reserves in unconventional reservoirs as well as 60-70% remaining oil in place in conventional petroleum reservoirs in the world, CO2-EOR will have even greater potential for world-wide application. However, CO2 flow and displacement behavior in reservoirs, in particular, in low-permeability reservoirs, is not still well studied or understood. The recent field observations and laboratory experiments indicate that effects of rock deformation and thermal condition have non-negligible impacts on the production performance of CO2-EOR. On the other hand, there are many approximations or limitations to model CO2-EOR processes under effects of rock compaction as well as under non-isothermal condition with current reservoir simulation techniques. There is no commercial simulator can handle such complicated flow behavior in CO2-EOR processes.

 

In this talk, we will present a multiphysical compositional CO2-EOR model, coupled with geomechanics and heat flow, which is a work-in-progress with capabilities to describe complex compositional flow behavior in multiphase multi-component, nonisothermal reservoirs. In this model, the fully coupled fluid and heat flow-geomechanics model is developed from the linear elastic theory for the poro-elastic system. The rock compaction is then correlated with stress-and temperature dependent rock properties through the flow-stress coupling process. We will present several simulation examples for insight of CO2-EOR processes.