Influence of CO2 flooding mode on oil displacement effect and reservoir damage in heterogeneous multi-layer reservoirs

被引：0

作者：

Wang Q. ^{[1
]}

Yang S. ^{[1
]}

Bai J. ^{[2
]}

Qian K. ^{[1
]}

Li J. ^{[1
]}

机构：

[1] College of Petroleum Engineering, China University of Petroleum, Beijing

[2] Research Institute of Oil/Gas Technology, PetroChina Changqing Oilfield Company, Xi'an, 710021, Shaanxi

来源：

Shiyou Xuebao/Acta Petrolei Sinica | 2020年 / 41卷 / 07期

关键词：

Asphaltene precipitation; CO[!sub]2[!/sub] flooding; CO[!sub]2[!/sub]-formation water-rock interaction; CO[!sub]2[!/sub]-WAG flooding; Multi-layer heterogeneous reservoir; Permeability reduction; Remaining oil distribution;

D O I：

10.7623/syxb202007009

中图分类号：

学科分类号：

摘要：

During the development of low-permeability reservoirs by CO2 injection, reservoir blockage caused by asphaltene precipitation and CO2-formation water-rock interaction exacerbates the complexity of displacement characteristics in heterogeneous multilayer sandstone reservoirs, thus affecting the seepage of fluids in reservoirs and final oil recovery during CO2 and CO2-WAG flooding. In this study, the CO2 and CO2-WAG flooding experiments were conducted in simulated multi-layer reservoir systems with similar physical properties under miscible conditions (70℃, 18 MPa). The two displacement modes were evaluated in terms of oil and gas production, remaining oil distribution and permeability damage. The experimental results show that the oil recovery of the entire system is lower after CO2 flooding, the oil production is mainly from the high permeability layer, the remaining oil is distributed in the medium and low-permeability layers. During the CO2-WAG flooding, the CO2 breakthrough time was late, and the oil recovery of the entire system was significantly improved. In addition, the permeability of the high-permeability layer decreased by 16.1% after CO2 flooding, and 95.1% of the decrease was caused by asphaltene precipitation. However, after CO2-WAG flooding, the permeability of each layer decreased by 29.4%, 16.8%, and 6.9%, respectively. Asphaltene precipitation is still the main factor and causes even more serious reservoir blockage. Moreover, the permeability decline caused by CO2-formation water-rock interaction in the high-permeability layer cannot be ignored, contributing 20.7% of the corresponding factors. Therefore, for multi-layer reservoirs with strong heterogeneity, CO2-WAG flooding has better oil displacement effect, but the prevention and control measures for asphaltene precipitation are necessary. © 2020, Editorial Office of ACTA PETROLEI SINICA. All right reserved.

引用

页码：875 / 884and902

共 40 条

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