据岩心观察、薄片镜下鉴定、物性特征分析及测井资料,大牛地气田奥陶系马家沟组风化壳储层类型为低孔低渗致密性储层.可将储层分为四类,其中最主要的类型为孔隙型储层,其次为溶蚀孔洞型储层和裂缝-孔洞型储层,再次为裂缝型储层.纵向上,以马家沟组五1、五2五4、五5亚段为储层发育段.预测了有利储层在平面上的分布.

Abundant petroleum resources are present in Ordovician Majiagou weathering-crust reservoirs in Daniudi Gas Field, Ordos Basin. Based on the analysis of core observation, thin section identification, reservoir property characters and logging data from the reservoirs, it is indicated that Majiagou reservoirs belong to tight ones with low porosity and low permeability. The reservoirs can be classified into the dissolved porosity reservoirs (in majority), the dissolved and fractured/vuggy ones and the fractured ones (in minority) in turn. In longitudinal, developing reservoir beds are Majiagou Ma1, Ma2, Ma4 and Ma5 members. Good reservoirs that distribute in plane are predicted for further exploration targets.