Feasibility study of improved unconventional reservoir performance with carbonated water and surfactant. (1st September 2019)

• Record Type: Journal Article
• Authors: Yu, Haiyang; Rui, Zhenhua; Chen, Zhewei; Lu, Xin; Yang, Zhonglin; Liu, Junhui; Qu, Xuefeng; Patil, Shirish; Ling, Kegang; Lu, Jun
• Is Part Of: Energy. Volume 182(2019)
• Page Start: 135
• Page End: 147
• Publication Date: 2019-09-01
• Subjects: Carbonated water injection -- Tight oil reservoir -- Core-flood experiment -- Numerical simulation -- Henry's law; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2019.06.024
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: For unconventional reservoirs, water flooding performs poorly because of low displacement efficiency; gas flooding shows limited enhanced oil recovery (EOR) capability due to gas breakthrough. Carbonated water injection (CWI) and active CWI (ACWI) are promising EOR methods which combine advantages of water and gas flooding. This paper provides experimental and numerical studies of carbonated water and surfactant injection based on a case study in Changqing Oilfield, China, which is the first time to investigate the feasibility of CWI and ACWI for tight oil reservoirs. This study compares performances of active water injection (AWI), CWI, Water altering gas (WAG), and ACWI. Experimental results reveal that the oil recovery of CWI is 2.7% more than WAG. ACWI achieves the highest incremental oil recovery (9.43%) among four methods. The sensitivity analyses of ACWI + WAG is further implemented experimentally, which demonstrates that ACW as a pre-flood improves 7% of oil recovery during WAG process. For Changqing tight reservoir cores, the optimal injection volume of ACW is 0.8 pore volume. Numerical simulations are conducted to validate the capability of cubic Equation-of-State coupled with Henry's law (EOS/H model) for CWI in tight oil reservoirs, indicating EOS/H model is applicable to correlate phase behavior of carbonated water and oil system. This paper, for the first time, investigates the EOR performance of ACWI in tight oil reservoirs. These results explore the feasible application of using CWI/ACWI in tight oil reservoir development. Highlights: Active carbonated water injection has potential application for tight oil EOR. ACWI followed by WAG can further improve oil recovery for tight oil reservoirs. The critical injected active carbonated water volume is about 0.8 PV during ACWI+WAG. The cubic equation of state coupled with Henry's law can simulate CWI more accurately.