Effect of stress sensitivity on displacement efficiency in CO2 flooding for fractured low permeability reservoirs |
| |
Authors: | Wang Rui Yue Xiang'an Zhao Renbao Yan Pingxiang and Dave Freeman |
| |
Affiliation: | (1) Key Laboratory of Petroleum Engineering, Ministry of Education, China University of Petroleum, Beijing, 102249, China;(2) SINOPEC Exploration & Production Research Institute, Beijing, 100083, China;(3) China Power Complete Equipment Co., Ltd., Beijing, 100011, China;(4) Edwy R. Brown Department of Petroleum Engineering, Marietta College, Marietta, USA |
| |
Abstract: | Carbon dioxide flooding is an effective means of enhanced oil recovery for low permeability reservoirs. If fractures are present
in the reservoir, CO2 may flow along the fractures, resulting in low gas displacement efficiency. Reservoir pore pressure will fluctuate to some
extent during a CO2 flood, causing a change in effective confining pressure. The result is rock deformation and a reduction in permeability with
the reduction in fracture permeability, causing increased flow resistance in the fracture space. Simultaneously, gas cross
flowing along the fractures is partially restrained. In this work, the effect of stress changes on permeability was studied
through a series of flow experiments. The change in the flowrate distribution in a matrix block and contained fracture with
an increase in effective pressure were analyzed. The results lead to an implicit comparison which shows that permeability
of fractured core decreases sharply with an increase in effective confining pressure. The fracture flowrate ratio declines
and the matrix flowrate ratio increases. Fracture flow will partially divert to the matrix block with the increase in effective
confining pressure, improving gas displacement efficiency. |
| |
Keywords: | Stress sensitivity flowrate distribution matrix fracture CO2 flooding displacement efficiency |
本文献已被 维普 SpringerLink 等数据库收录! |
| 点击此处可从《石油科学(英文版)》浏览原始摘要信息 |
|
点击此处可从《石油科学(英文版)》下载全文 |
|