Characteristics of the Chang 3 Reservoir in the Yangchang Formation,Linzhen Area,Ordos Basin

In order to acknowledge the characteristics of the Chang 3reservoir in the Linzhen area,a key oil and gas exploration area,which locates in the southwest Ordos Basin,reservoir sandstone samples and field data were systematically collected from this area.Petrologic characteristics,reservoir physical properties,diagenesis,diagenesis stage and diagenesis sequence and factors affecting reservoir properties were studied via rock-mineral analyses,physical property analyses,scanning electron microscope,mercury penetration data and logging data analyses.The results showed that the reservoir sandstone of Chang 3is of low porosity and low permeability.The reservoir,composed by arkose and debris-feldspar,is in the early diagenetic stage B period and have experienced compaction,cementation and dissolution.The pores are mainly intergranular pores and dissolved pores between grains.The compaction and carbonate-cementation destroye the primary-texture of pores intensively to deteriorate the physical property,while the chlorite-cementation and dissolution improve the physical property of the reservoir.