石油实验地质2026，Vol.48Issue(2)：310-322,13.DOI:10.11781/sysydz2026020310
东海盆地西湖凹陷保俶斜坡北段超深层甜点储层发育主控因素
Main controlling factors of ultra-deep sweet spot reservoir development in northern section of Baochu Slope,Xihu Sag,East China Sea Basin
摘要
Abstract
The Y area in the Xihu Sag of East China Sea Basin has superior conditions for hydrocarbon accumula-tion,with the T oil-gas structure already discovered,demonstrating significant exploration potential.Drilling confirms that the ultra-deep sweet spot reservoirs are key to hydrocarbon enrichment in this area.However,under the background of high sand-to-ground ratio,reservoir heterogeneity is strong,and the genetic mechanisms and main controlling factors of high-quality reservoirs remain unclear,which restricts the reserve growth and production enhancement in this region.Based on the analysis of petrological characteristics,storage properties,diagenesis,and diagenetic evolution of the Pinghu Formation and Baoshi Formation in the Y area,this study investigated the genetic mechanisms and controlling factors of deep to ultra-deep sweet spot reservoirs.In the Y area,ultra-deep sweet spot reservoirs were widely developed in the Baoshi Formation.A physical-property inversion zone of the sweet spot reservoirs developed below 4 600 m.Medium-to coarse-grained,thick-bedded channel sandstones with low argillaceous content were the dominant sedimentary facies.The constructive effects of chlorite in preser-ving pores,secondary dissolution in increasing pores,and overpressure were the main controlling factors for the development of sweet spot reservoirs.Chlorite occurred in three forms:grain coatings,pore linings,and pore fillings.The effective inhibition of compaction and quartz overgrowth by early-stage chlorite coatings was a key factor in the formation of sweet spot reservoirs.During the early diagenetic stage A,acidic fluids generated from organic matter dissolved feldspar to form secondary pores,further improving reservoir properties.Additionally,overpres-sure could inhibit compaction and form micro-fractures to promote dissolution,also contributing to improved physical properties.Based on the differences in sedimentary characteristics,diagenesis,and diagenetic evolution sequences between the Pinghu Formation and the Baoshi Formation,three reservoir evolution models were estab-lished for the study area:sweet spot reservoir evolution model of"early chlorite coating pore preservation-later dissolution pore increase-late overpressure relay pore preservation and permeability increase";tight reservoir evo-lution model of"early strong siliceous cementation-later weak dissolution";and tight reservoir evolution model of"early strong compaction-middle weak dissolution-late iron calcite cementation".The first sweet spot reservoir evolution model provides a foundation for oil and gas exploration of ultra-deep formation in new areas and new fields of the Y area.关键词
成因机制/主控因素/甜点储层/平湖组/宝石组/保俶斜坡/西湖凹陷Key words
genetic mechanism/main controlling factors/sweet spot reservoir/Pinghu Formation/Baoshi For-mation/Baochu Slope/Xihu Sag分类
能源科技引用本文复制引用
张尚虎..东海盆地西湖凹陷保俶斜坡北段超深层甜点储层发育主控因素[J].石油实验地质,2026,48(2):310-322,13.基金项目
中国石化科技部项目(025013)资助. （025013）
