油层纵向渗透率非均质性对蒸汽驱开采效果的影响

应用数值模拟的方法和渗透率变异系数的概念，研究了３各类型稠油油藏纵向渗透率非均质性对蒸汽驱开采效果的影响规律。结果表明：稠油油藏纵向渗透率非均质性对蒸汽驱开采效果有较大影响，其影响大小不仅与渗透率非均质程度有关，而且与沉积旋回有关。同时指出，要提高纵向渗透率非均质性严重的稠油油藏的蒸汽驱开采效果，应采取有效措施防止蒸汽带过早突破，提高蒸汽波及效率。

EFFECTS OF RESERVOIR VERTICAL PERMEABILITY HETEROGENEITY ON STEAMELOOD

The reservoir vertical permeability heterogeneity, has strong effects on steamflood in heavy oil reservoirs. First, because of vertical permeability heterogeneity, steam is dominantly injected into the oil formations with high permeability, and results in earlier steam breakthrough. Second, because of gravitational differentiation, steam overriding is common. The above two factors will result in poor displacement efficiency and low oil recovery. In this paper, the permeability heterogeneity is represented by the permeability variation coefficient. And all work of the study is based on the thermal numerical simulation. Authors of this studied the effects of vertical permeability heterogeneity and permeability sedimentary cycle on steamflood in three types of heavy oil reservoir including massive, multi-layers and single-layer reservoirs. Effects of different perforation interval on steamflood in reverse cycle heavy oil reservoir are also studied in this paper. The result indicates: (1)The stronger the vertieal permeability heterogeneity is, the poorer steamflood effectiveness is. (2)The steam flood effect is good for positive cycle,the poorest for reverse cycle and the medium for composite cycle at the same value of vertical permeability variation coefficient in heavy oil reservoirs. (3)In order to improve steam sweep efficiency to increase oil recovery, it needs to adopt a certain ef fective method to avoid steam early breakthrough and stronger steam overriding, especially in heavy oil reservoir with stronger vertical permeability heterogeneity.