A Study On Reservoir Characteristics And Control Factors Of The Chang 6 Formation In Diantou—Longfang Area Of The Ordos Basin

This paper made in-depth research of characteristics and control factors study of thechang 6 formation in Huangling Diantou—Longfang area,by closely combined with the actual exploration,with multidisciplinary geological theory of sedimentology,reservoir geology and petroleum geology and technology for guidance,made full use of cores,thin sections,analysis as well as log date.Set up the regional stratigraphic framework through fine stratigraphic division and correlation of the objective interval strata;Research of characteristics of the sedimentary microfacies and the sand body distribution by systematically analyzed a number of depositional symbols of petrology,grain size characteristic,sedimentary structure and well-logging;Confirmed control factors of influencing the reservoir quality in Huangling Diantou—Longfang area from analyzing clastic particles,the sedimentary microfacies,the correlation of cement content and poroperm and distribution plane characteristics of crevice,with combining qualitative and quantitative,based on deeply cognized diagenesis,essential characteristic and heterogeneity of reservoir.The main ideas are as follows:The paper suggests that the oil bearing layer Chang 6 in study area belongs to the gravity flow-lake deposit system with a water and reductive depositional environment.The sandy clastic flow and the favorable fades belts for developing reservoir was lobes,interlobe,turbidity channel,the edges among the turbidity channel;The main diagenesis in the studied area included the compaction,cementation,metasomatism,dissolution and rupture;The diagenesis of the reservoir sandstone of Chang 6 is during the period of middle diagenesis A-B;The Chang 6 reservoir sandstone mainly is fine-very fine arkose and the main type of pore is dissolution intergranular pore,It belongs to extremely low porosity with extremely low permeability reservoir.The pore texture of Chang-6 member is small sized porosity with minute throats and the fracture of this area is very common.The paper holds that the reservoir is controlled by sedimentary microfacies,diagenesis and the tectonization.