小断块油藏CO2单井吞吐强化采油可行性研究

受多断层切割的复杂断块油藏,所形成的众多小断块单元油藏井间连通性差、边界封闭、地层能量有限、开采中地层能量下降快、难以采用早期注水等方式大规模开采.而采用CO2吞吐强化采油方式对此类油藏可能是一种有效的方法.为此,针对复杂小断块低能量油藏单元的地质开发特征,在对油井目前地层流体进行相态分析基础上,通过CO2-油藏流体膨胀实验,确定CO2吞吐的驱替机理,再通过CO2吞吐长岩心驱替实验确定CO2吞吐增产原油的程度和时效性.然后建立了针对实际小断块单元油藏单井CO2吞吐的地质和数值模拟模型,在对注气前油井生产动态进行历史拟合基础上,对CO2吞吐强化采油过程中的工艺操作参数进行了敏感性分析,重点讨论注气时机和周期注入量对小断块单元油藏增产效果的影响,分析不同注气时机CO2吞吐前后近井地层原油饱和度和压力分布变化规律.从而得出适合于小断块单元油藏CO2单井吞吐强化采油的有效时机和最佳操作参数选择,为小断块单元油藏实施CO2吞吐强化采油可行性方案设计提供了系统的室内综合评价方法.

The Feasibility of Small Fault Block Cell Oil Reservoir Single Well CO2 Huff and Puff Research

It is difficult for complicated small fault block oil reservoir unit by many faults to commercial-scale operation by water injection because of communication difference among wells, boundary seal, producing energy finite, producing energy falling soon during exploitation. It may be a kind of powerful method with CO2 huff and puff forced production to this kind of reservoir. Thus aiming at these complicated small fault block oil reservoir characteristic of geology and exploitation, on a basis of phase state analyses to the actual fluid of the oil well, by carrying out CO2 swelling experiment, drive mechanism of CO2 huff and puff is confirmed. And by CO2 huff and puff long core drive experiment, oil increasing production degree and time phase are confirmed. Under that foundation geologic model and numerical simulation model of single well CO2 huff and puff are established aiming at actual small fault block oil reservoir. After carrying out fitting to producing history before gas injection, sensitivity analyses are carried out of operation parameters during CO2 huff and puff forced production, it has been stress reviewed the influence of in- jection occasion and cycle injection rate to effect of increasing production of small fault block oil reservoir unit, saturation and pressure distributing of different injection occasion are analyzed. Thereby effective and optimal operation parameters of small fault block cell oil reservoir single well CO2 huff and puff forced production are derived, and systemic indoor integrative evaluation method is supplied for project design of small fault block cell oil reservoir single oil well CO2 huff and puff.