声波测井关联维评价潜山储层裂缝尺度

Evaluation of fracture scale of buried-hill reservoirs with the associated dimension of sonic logs

成都理工大学, 四川成都610059

Chengdu University of Science and Technology, Chengdu 610059, China

潜山储层声波测井能够指示裂缝,但基本不能描述裂缝尺度。通过对已知的潜山裂缝层段进行声波测井关联维分析,进一步证实了潜山裂缝属于分形体系,同时得出如下结论:①声波测井关联维数大小指示了裂缝发育宽度与延展性;②宽度中等裂缝(中尺度裂缝)与宽度宽且延伸长(大尺度裂缝)的裂缝不仅表现在声波测井关联维的差异上,而且稳定相空间的维数及求取关联维维数时的采样间隔也有区别;③微裂缝(小尺度裂缝)声波测井关联维最小,且关联维的大小对应于裂缝尺度大小。

Sonic log of buried-hill reservoirs is able to indicate the existence of fractures, but it is generally incapable of describing the fracture scale. The analysis of associated dimension of sonic logs performed at the fracture intervals of known buried hills confirms that fractures of buried hills belong to fractal system. In addition, three other conclusions are arrived. 1) The amount of associated dimension indicates fracture width and extension. 2) The difference betweenmedium scale fractures (i.e. fractures withmedium width) and large scale fractures (i.e. fractures with large width and extension) shows off in two ways. One is the associated dimension, the other is the dimension of stable phase space and sampling spacing used in calculation of the associated dimension. 3)micro-scale fractures (i.e. fractures withmicrofractures) have the least associated dimension of sonic log, and the amount of the associated dimension is proportional to fracture scale.