关键词: 歧口凹陷, 沙河街组一段, 纹层状互层, 颗石灰岩, 储集能力

Abstract:

In the Es1 Formation in Qikou Sag, the interlaminated coccolith limestone and mudstone develops extensively, in some literature, it is classified as “oil shale” because of the oil bearing. Predecessors have done many researches on the hydrocarbon accumulation potential of coccolithophorida, however, the reservoir characteristics research of coccolith limestone is still not taken seriously. So, through scanning electron microscope, density measuring, the irregular sample porosity measuring and well logging interpretation etc., the authors of the paper mainly research the reservoir characteristics of coccolith limestone. It is discovered that the inter granular pores and intra granular pores of coccoliths develop extensively and distribute evenly in coccolith limestone, and the average porosity of interlaminated coccolith limestone and mudstone can reach 16.0%, the permeability is (1~100)×10^-3μm². So, coccolith limestone is of good reservoir property. The interlaminated coccolith limestone and mudstone is potential oil reservoir.

Key words: Qikou Sag, Es1 Formation, interlaminated coccolith limestone and mudstone, coccolith limestone, reservoir capacity