Characteristics Of Chang6Reservior In Hujianshan—Wuqi Area, Ordos Basin

On the basis of the former research achievements and acquired information, with the new theories and methods, including sedimentology, structure geology, logging geology, reservoir geology, petroleum geology, this article systematically analyzed the sedimentary facies, reservoir characteristics of the Chang6oil-bearing formation in Hujianshan—Wuqi area, Ordos basin. According to the lithologic features, electrical property, sedimentary rhythm, and the distribution of regional marked beds, The Chang6oil-bearing formation of the researched area can be divided into three oil layers, i.e. Chang6i; Chang62and Chang63. The results show that each oil layer has the resemble structure property which is similar to the regional structure. They all display the feature of monocline, with some nose-shaped uplifts.According to a series of facies symbols, combined with regional depositional background, the author discussed the types of sedimentary facies, microfacies and their characteristics of the Chang6oil-bearing formation in the studied area. It is considered that the chang6formation in studied area is a set of lake delta deposition with delta front subfacies mainly, including subaqueous distributary channel, interdistributary bay, channel-mouth bar and sheet sand microfacies. Based on core observation and rock slice identify, the physical property of the Chang6oil-bearing formation in Hujianshan—Wuqi area is poor. Generally, the reservoir’s physical properties are low-extralow porosity and extralow-ultralow permeability. And then the author totally analyse the aeolotropism and the sensitivity of reservoir. The Chang6oil-layer reservoir can be divided in to4types,i. e. type Ⅰ (good), type Ⅱ (fair), type Ⅲ (poor), type Ⅳ (very poor), according to physical properties(porosity;permeability),the size of sand and the main pore structure. The type of Chang6resevoir is main type Ⅲ (poor) in studied area.