An Experimental Investigation of WAG Injection in a Carbonate Reservoir and Prediction of the Recovery Factor Using Genetic Programming

Energies

Mateusz Gawroński¹  Jan Lubaś²  Marcin Warnecki²  Jerzy Kuśnierczyk²  Mirosław Wojnicki²  Sławomir Szuflita² 

[1] Department of Robotics and Mechatronics, AGH University of Science and Technology, 30-059 Krakow, Poland;Oil and Gas Institute—National Research Institute, 31-503 Krakow, Poland;

关键词: enhanced oil recovery;    WAG;    carbonate reservoir;    CO₂;    acid gas;    high-nitrogen natural gas;   

DOI  :  10.3390/en15062127

来源: DOAJ

【 摘 要 】

Production from mature oil fields is gradually declining, and new discoveries are not sufficient to meet the growing demand for oil products. Hence, enhanced oil recovery is emerging as an essential link in the global oil industry. This paper aims to recognize the possibility of increasing oil recovery from Polish carbonate reservoirs by the water alternating gas injection process (WAG) using various types of gases, including CO₂, acid gas (a mixture of CO₂ and H₂S of 70/30% vol/vol) and high-nitrogen natural gases occurring in the Polish Lowlands. A series of 17 core flooding experiments were performed under the temperature of 126 °C, and at pressures of 270 and 170 bar on composite carbonate cores consisting of four dolomite core plugs. Original reservoir rock and fluids were used. A set of slim tube tests was conducted to determine the miscibility conditions of the injected fluids with reservoir oil. The WAG process was compared to continuous gas injection (CGI) and continuous water injection (CWI) and was proven to be more effective. CO₂ WAG injection resulted in a recovery factor (RF) of up to 82%, where the high nitrogen natural gas WAG injection was less effective with the highest recovery of 70%. Based on the core flooding results and through implementing a genetic programming algorithm, a mathematical model was developed to estimate recovery factors using variables specific to a given WAG scheme.

【 授权许可】

Unknown