RPSEA Phase 1

RPSEA Funded Research

Near Miscible CO2 Application to Improve Oil Recovery for Small Producers

Carbon dioxide (CO2) injection for enhanced oil recovery is a proven technology. It is also considered as one of the most promising methods for carbon sequestration in geologic formations. CO2 injections are normally operated at a pressure above the minimum miscibility pressure (MMP), which is determined by crude oil composition and reservoir conditions. However, many reservoirs in the United States and around the world are at shallow depths or geologic conditions exist such that they operate at pressures below the MMP. The goal of this project is to demonstrate near miscible CO2 application can substantially increase oil productions with CO2 injection at pressures below MMP. The application of CO2 injection at near miscible conditions may lead to development of CO2 projects for small producers in reservoirs where the MMP is not attainable at current operating reservoir pressures.

When CO2 injection operates at a pressure below the MMP, displacement efficiency decreases as a result of the loss of miscibility. Near miscible displacement generally refers to the process occurring at displacement pressures below the MMP, but the actual pressure range has never been clearly defined. At displacement pressures near miscible, significant oil recovery has been observed in slim-tube experiments and to a lesser extent in core tests. This better recovery has been attributed to possible improvement of the mobility ratio in the displacement and an extraction process, both of which are closely related to operating pressure. To increase the resource base for CO2 flooding and substantially increase the production from reservoirs operated by small producers, it is proposed to investigate the feasibility of applying CO2 displacement at near miscible pressures by conducting appropriate experimental work and reservoir simulation.

The project includes both experimental and computational studies. In the experimental study, work will 1) systematically characterize the near miscible condition and study recovery of waterflood residual oil using CO2 displacement at near miscible pressures, and 2) identify key parameters in phase behavior and flow tests for simulation modeling.

In the computational study, the work will 1) develop a representative model to simulate near miscible displacement physics and 2) assess the potential of recovery processes at near miscible pressures.

This project is a joint effort by the Tertiary Oil Recovery Project (TORP) at the University of Kansas and Carmen Schmitt, Inc. (Kansas independent producer). The successful completion of this feasibility study will lead to future field demonstration pilots in producing areas operated by our project partner in the Arbuckle formation. The potential benefits will be significant with an increase in the resource base for CO2 flooding and an expanded opportunity for small producers to apply CO2 flooding.

This project is funded by RPSEA under the Unconventional Onshore & Small Producer Program. The Principal Investigator is Dr. Jyun-Syung Tsau, and graduate students are Ly Huong Bui and WoanJing Teh.

Project Progress

SPE Project Presentation #129710

SPE Project Presentation #129728

SPE Technical Paper #129710

SPE Technical Paper #129728

RPSEA final report pages 1-33
RPSEA final report pages 34-57
RPSEA final report pages 58-68
RPSEA final report pages 69-79
RPSEA final report pages 80-92