准噶尔盆地南缘西段齐古组深层储层特征及物性控制因素OA北大核心CSTPCD

The deep clastic reservoir of Qigu Formation in the western section of the southern margin of Junggar Basin has a great potential for oil and gas exploration.However,there is still a lack of systematic studies on its reservoir characteristics and control of physical properties,which seriously restricts the subsequent oil and gas exploration.With the combination of the relevant studies of regional burial history and paleogeothermal tempera-ture,this paper comprehensively utilized the data of casting thin sections,scanning electron microscopy,physi-cal properties,mercury intrusion and inclusions,and systematically studied the petrological characteristics,physical properties,diagenesis characteristics,and physical property control of the Qigu Formation reservoir.The results show that the Qigu Formation reservoir exhibits the petrological characteristics of low compositional maturity,high plastic debris content,and medium structural maturity.Although the buried depth of the reser-voir center is more than 3,500 m,the reservoir space is still dominated by the intergranular pores,with an aver-age porosity of 10.29％and an average permeability of 34.12×10-3 μm2.In general,it belongs to the catego-ry of low porosity and low permeability reservoirs with limited development of some medium-high porosity and permeability reservoirs.The diagenesis of the reservoir mainly includes compaction,cementation,and dissolu-tion,and the diagenesis intensity is relatively weak.The main body is at the early diagenesis(stage B)to mid-dle diagenesis(stage A),and it is characterized by medium compaction intensity,low cement content,and acid dissolution at the late stage.In particular,the characteristics of enriched quartz and feldspar,poor cut-tings,and good sorting are conducive to the preservation of reservoir physical properties.