Characteristics Of Chang6Reservoir And Favourable Target Forecasting In Yangmijian-Qingyangcha Area

Yangmijian-Qingyangcha area is located in the central section of Shanbei slope of Ordos Basin. According to the present exploration results, the petroleum resources of Yanchang Formation in this area are abundant, and the main reservoir is Chang6oil-bearing beds, but it has been limited researched.Based on various data of drilling, logging, well analysis and test, using the methods and theories of petroleum geology, sedimentology, reservoir geology and logging geology, this article studies Chang6oil-bearing beds with these factors:stratigraphic division and contrast; sedimentary facies identification; sedimentary facies belt and bodies extension; and the research of the structure and heterogeneity of the reservoir pore, in order to discuss the main dominating factors. And this reservoir stratum has been classified and evaluated, with all the studies and the formation testing data, we have gotten the division standard of favorable targets and have optimized the selection of these targets at the same time.The study shows that Yangmijian-Qingyangcha area mainly belongs to delta front subfacies deposit, and the subaqueous distributary channel body is the framework of the reservoir, and the direction of the sandbodies generally expread from NE to SW, with the Chang61and Chang62the best development.The target reservoir rock mainly belongs to the arkose, and the diagenetic stage has stepped to the middle stage, A period. The pore type is mainly remains-interparticle pore, next is feldspar dissolved pore and lomonitite dissolved pore. The pore structure mainly consists of small pore-fine throat, small pore-micro-fine throat. The reservoir properties is poor, belonging to low porosity and very low permeability-low porosity and extremly low permeability reservoir, mainly controlled by sedimentary microfacies, diagenesis and the latter tectonism.According to the division standard of favorable targets, the authour has predicted two typeⅣ in Chang63; one type Ⅰ, two type Ⅱ, one typeⅢ and one type Ⅳ in Chang622; one type Ⅰ, two type Ⅱ, one type Ⅲ and two type Ⅳ in Chang621; two type Ⅱ, one type Ⅲ, two type Ⅳ in Chang612; two type Ⅰ, one type Ⅱ, one type Ⅲ in Chang611.