变质岩裂缝性潜山油藏注气提高采收率研究

STUDY OF EOR BY GAS INJECTION IN BURIED HILL RESERVOIRS CONSISTING OF FRACTURED METAMORPHIC ROCKS

X油藏是变质岩裂缝性潜山油藏,岩性复杂,含油幅度高,受裂缝发育影响,储层非均质性强,可借鉴的经验少,为保持高产稳产,采用合理的人工能量补充方式,迫切需要研究注气提高采收率的可行性。该文用网状缝制造技术对天然岩心造缝后在模拟地层温度108.5℃、地层压力34.47 MPa下,开展了纵向顶部气驱、底部水驱和水平衰竭长岩心驱替实验研究。结果表明,纵向顶部气驱油效率最高,驱油效率为73.88%;水平衰竭驱替次之,为56.01%;纵向底部水驱油效率最低,为54.65%,说明该油藏比较适合顶部伴生气驱或干气驱。

There is a fractured metamorphic rock and buried hill reservoir, complex in lithology, high oil rate, highly heterogeneous and affected by the fracture, so has little experience. In order to maintain high and stable yield, a reasonable artificial-energy supplementary way is to be used. There is an urgent need to study the feasibility of EOR by gas injection. Under the condition of formation temperature 108.5℃ and pressure 34. 47MPa, the seam core manufacturing techtaology to build a natural seam is used to develop long core test, which include top longitudinal gas drive, vertical bottom of water flooding and horizontal depletion. According to laboratory findings, gas drive has the highest displacement efficiency 73.88%, followed by depletion, its efficiency is 56.01%, and the third one is water flooding, its efficiency is just 54.65%. It is obvious that this reservoir is more suitable for the top of associated gas drive or dry-gas drive.