鄂尔多斯盆地合水地区延长组7段深水致密砂岩储层特征及主控因素OA

In recent years,reservoirs exploration in the 7th member of Yanchang Formation(Chang 7 Member)in southwestern Ordos Basin has made significant breakthroughs,but the main controlling factors for the development of tight sandstone reservoirs remain controversial,restricing further development.Based on the results of core obser-vation,thin section identification,physical property tests and high-pressure mercury intrusion analysis,character-istics and main controlling factors of deep-water gravity flow reservoirs in Chang 7 Member of Heshui area are stud-ied.The results show that reservoir rocks of Chang 7 Member in Heshui area are mainly lithic feldspathic sandstone,feldspathic lithic sandstone and feldspathic sandstone,with authigenic clay minerals as the primary interstitial mat-ter and hydromica the most.Reservoirs pore types include intergranular pores and feldspar dissolved pores and are divided into 3 types of pore structures.Sandy debris flow and turbidite sandbodies developed in semi-deep lake-deep lake background provide a sedimentary basis for reservoir development.Burial compaction deteriorates the physical properties of sandy debris flow reservoirs,while cementation is the main reason for quality loss in turbidite reservoirs.Feldspar dissolved pores improve the reservoir quality,and fractures significantly improve the reservoir and seepage performance.The research provides references for the development of tight sandstone reservoirs in Chang 7 Member of Heshui area.