Abstract:

Structural fractures developed well in Aershan reservoir, Hanan Oilfield. The width of the micro-fractures is 10～30 pin, the length is 1～3 mm and surface density is 0.025 mm². The micro-fracture porosity and permeability have been calculated, and the distribution is analyzed. Micro-fractures are preface of macrn-fractures and the macro-fracture developed areas are also micro-fracture developed areas. A sandstone micro-model experiment has been done to investigate the process of displacement between fractures and matrix. Based on the above studies, micro-fractures play two different roles on waterflooding. On one hand, they may improve the permeability of the reservoirs; on the other hand, the together with macro-fractures and faults may improve network, which have bad effect on waterflooding. According to the characteristics of,micro-fractures in Aershan reservoir, some suggestions such as periodic injection are put forward to improve the effect of waterflodding in fracture-developed areas.

Key words: Hanan Oilfield, Aesshan reservoir, reservoir micro-fractures, waterflooding