The study of reservoir rock damage induced by gas injection is of great significance to the design of reservoir stimulation and the improvement of oil and gas recovery. Based on an example horizontal well in the Hudso...The study of reservoir rock damage induced by gas injection is of great significance to the design of reservoir stimulation and the improvement of oil and gas recovery. Based on an example horizontal well in the Hudson Oilfield of the Tarim Basin and considering the multi-physics coupling effects among highpressure fluid, rock deformation, and damage propagation during CO_(2) injection, a three-dimensional finite element model for CO_(2) injection in deep reservoir considering seepage-stress-damage coupling was developed. The evolution of reservoir rock damage under different CO_(2) injection conditions was systematically investigated. The results show that tensile damage and shear damage are concentrated in the vertical direction and the horizontal maximum compressive principal stress direction, respectively,and the tensile damage is the main damage mode. At higher CO_(2) injection rate and pressure, the damaged areas near the wellbore are mainly distributed in the direction of the maximum compressive principal stress, and the development of the damaged area near the wellbore will be inhibited by the formation and evolution of far-field damage. CO_(2) injection aggravates the extension of tensile damage,but inhibits the initiation of shear damage, and eventually leads to the gradual transition from shear damage to tensile damage. Under the same injection conditions, CO_(2) injection has superior performance in creating rock damage compared with the injection of nitrogen and water. The results in this study provide guidance for enhanced oil recovery in deep oil and gas reservoirs with CO_(2) injection.展开更多
基金the Projects Supported by the National Science Foundation of China (41972138, 52074312)the National Science and Technology Major Project of China(ZD2019-183-007) for the financial support。
文摘The study of reservoir rock damage induced by gas injection is of great significance to the design of reservoir stimulation and the improvement of oil and gas recovery. Based on an example horizontal well in the Hudson Oilfield of the Tarim Basin and considering the multi-physics coupling effects among highpressure fluid, rock deformation, and damage propagation during CO_(2) injection, a three-dimensional finite element model for CO_(2) injection in deep reservoir considering seepage-stress-damage coupling was developed. The evolution of reservoir rock damage under different CO_(2) injection conditions was systematically investigated. The results show that tensile damage and shear damage are concentrated in the vertical direction and the horizontal maximum compressive principal stress direction, respectively,and the tensile damage is the main damage mode. At higher CO_(2) injection rate and pressure, the damaged areas near the wellbore are mainly distributed in the direction of the maximum compressive principal stress, and the development of the damaged area near the wellbore will be inhibited by the formation and evolution of far-field damage. CO_(2) injection aggravates the extension of tensile damage,but inhibits the initiation of shear damage, and eventually leads to the gradual transition from shear damage to tensile damage. Under the same injection conditions, CO_(2) injection has superior performance in creating rock damage compared with the injection of nitrogen and water. The results in this study provide guidance for enhanced oil recovery in deep oil and gas reservoirs with CO_(2) injection.
