JZS油田裂缝性潜山油藏基质驱油效率研究

摘要

In order to investigate oil flow process between matrix and fractures in fractured buried hill reservoirs and quantify oil displacement efficiency in matrix,fractured buried hill reservoir in JZS oil field is used as a prototype to build single fracture model and investigate oil displacement efficiency in matrix,for which a diagram is drawn. Oil displacement driving force research shows that when matrix permeability is smaller than 3×10-3μm2,capillary im-bibition is the major driving force and displacement force is secondary and that when matrix permeability is larger than 3×10-3μm2,displacement force is the major driving force and capillary imbibition is secondary. Oil displace-ment research shows that oil displacement efficiency in matrix declines rapidly with the increment of formation oil viscosity. The property of JZS oil field is taken as an example. When matrix permeability is 1×10-3μm2 and forma-tion oil viscosity increases from 3 mPa · s to 200 mPa · s,oil displacement efficiency in matrix declines from 12. 5% to 3. 2%. The oil displacement efficiency in matrix for fractured buried hill reservoir in JZS oil field is 12. 5%,among which imbibition contributes 10. 1% and displacement force contributes 2. 4%. The research results provide guidance for development strategy determination of fractured buried hill reservoirs and the oil displacement efficiency diagram provides basis for recovery calibration of this type of reservoirs.%为研究裂缝性潜山油藏基质与裂缝的出油过程,定量基质驱油效率,以JZS油田裂缝性潜山油藏为原型,建立单裂缝模型,研究基质的驱油效率,绘制基质驱油效率图版.驱油动力研究表明,当基质渗透率小于3×10-3μm2时,基质驱油主要动力为渗吸作用,其次为驱替作用,当基质渗透率大于3×10-3μm2时,基质驱油主要动力为驱替作用,其次为渗吸作用.驱油效率研究表明,基质驱油效率随地层原油黏度增加急剧降低,以JZS油田物性特征为例,当基质物性为1×10-3μm2时,地层原油黏度由3 mPa·s增至200 mPa·s,基质驱油效率由12.5%降至3.2%.JZS油田裂缝性潜山油藏基质驱油效率为12.5%,其中渗吸作用贡献10.1%,驱替作用贡献2.4%.研究成果对裂缝性潜山油藏制订开发策略具有指导意义,同时驱油效率图版可为该类油藏标定采收率提供依据.