中国石油大学学报（自然科学版）2018，Vol.42Issue(4)：91-99,9.DOI:10.3969/j.issn.1673-5005.2018.04.011
基于B-L方程的低渗透油藏CO2水气交替注入能力
Injectivity of CO2WAG in low permeability oil reservoirs based on B-L equations
摘要
Abstract
The loss of injectivity has become one of the key factors restricting the recovery efficiency in CO2water-alterna-ting-gas (WAG) projects for low permeability reservoir.In this paper, considering the solubility of CO2in oil and water and the evaporation of oil components by CO2, a method of characteristics was used, and a retardation factor was introduced to modify the Buckley-Leverett(B-L) equations during CO2flooding and water displacing CO2.Then, the front and rear velocity for CO2flooding and water displacing gas can be determined.A mathematic model to calculate the injectivity of CO2WAG was proposed based on the flowing theory of composite reservoirs and the front and rear velocity of CO2and water flow in the WAG process.The methods of Laplace transformation and Stehfest numerical inversion were applied to solve the model and obtain an approximate solution of the bottom-hole pressure.The analytical model was verified by numerical simulation results for reservoirs with different permeability.Sensitivity analysis shows that, in comparison with partial oil-wet reservoirs, the in-jectivity of water is lower for partial water-wet formations.The water injectivity increases with the reduction of CO2-oil interfa-cial tension.When the reservoir permeability is lower than 5×10-3μm2, the injectivity of water deceases significantly.关键词
低渗透油藏/CO2水气交替驱/注入能力/B-L方程/复合模型Key words
low permeability oil reservoir/water-alternating-CO2flooding/injectivity/B-L equations/composite model分类
能源科技引用本文复制引用
孟凡坤,苏玉亮,郝永卯,李亚军,童刚..基于B-L方程的低渗透油藏CO2水气交替注入能力[J].中国石油大学学报（自然科学版）,2018,42(4):91-99,9.基金项目
国家"973"重点基础研究发展计划项目(2014CB239103) （2014CB239103）
国家自然科学基金项目(51674279) （51674279）
教育部长江学者和创新团队发展计划项目(IRT1294) （IRT1294）
"十三五"国家油气重大专项(2016ZX05015-003) （2016ZX05015-003）
