新型非均相复合驱油方法

A study on the heterogeneous combination flooding system

利用流变仪、界面张力仪、激光粒度仪、微观驱油和驱油物理模拟等装置,通过实验筛选出了驱油用黏弹性颗粒驱油剂(PPG)样品,评价了其应用性能;研究了PPG与聚合物及表面活性剂间的相互作用规律,设计了非均相复合驱油体系,评价了其在胜利油田高温高盐、聚合物驱后油藏条件下的提高采收率效果。结果表明,驱油用PPG能够在多孔介质中运移并通过在孔喉处的堆积—堵塞—压力升高—变形通过来改变已形成的优势通道,具有比聚合物更强的扩大波及能力。PPG与聚合物复配后能够增强体系的黏度与黏弹性能,因而PPG与表面活性剂和聚合物组成的非均相复合驱油体系具有比聚合物驱更强的扩大波及体积能力和与复合驱相似的洗油能力。在双管模型渗透率级差为(1 000∶5 000)×10-3μm2时,在胜利油田高温高盐油藏条件下可提高采收率22.5%,在胜利油田孤岛中一区Ng3聚合物驱后的油藏条件下,可进一步提高采收率19.1%。

A novel preformed particle gel（PPG） as a chemical EOR was screened out by means of the rheometer,interfacial tensiometer,laser particle analyzer,microscopic oil displacement and physical simulation of oil displacement.The present paper evaluated its properties in application,investigated the mutual interaction between the PPG and other polymers or surfactants,designed a heterogeneous combination flooding system（HCFS）,and appraised the EOR effect of this new system under the condition of high-temperature,high-salinity and after-polymer-flooding reservoirs in the Shengli Oilfield.The results indicated that PPG could not only migrate and penetrate through porous mediums,but also generate a more significantly sweeping efficiency by means of piling up,plugging,pressure rising and deforming at throats to modify the existing dominant migration paths,and it was of a greater volumetric-expansion capacity than conventional polymers.Because the combination of the PPG and polymers could enhance the viscosity and viscoelasticity of a system,the heterogeneous combination flooding system（HCFS） composed of the PPG,surfactants and other polymers is of a displacement efficiency similar to the combination flooding.Under the experimental condition of a dual sand-packed tube flooding with the interlayer heterogeneity of（1 000∶5 000）×10-3μm2,the HCFS could improve the oil recovery by 22.5% for HT/HS reservoirs in the Shengli Oilfield and by 19.1% for the Ng3 reservoirs after polymer flooding in the Zhong-1 section of the Gudao Oilfield.