关键词: 主控因素, 成岩环境, 超压, 碎屑岩, 中-深层储层, 琼东南盆地

Abstract:

The study aims to clarify the reservoir development characteristics and genetic mechanisms of different zones. A batch of analytical data is applied to comprehensively investigate the medium-to-deep clastic reservoirs in the Yacheng uplift， Yacheng 13-1 low uplift， and Ya’nan low uplift， focusing on the reservoir characteristics and diagenetic environment， as well as the main factors controlling the high-quality reservoir development. The results indicate that the clastic reservoirs in Yacheng uplift mainly consist of the deltaic sandstone of the Neogene Sanya Formation， characterized by fine grain sizes. These reservoirs exhibit burial depths ranging from 2 800 to 3 100 m， suggesting a normal temperature and pressure （NTP） environment， and with grains predominantly in point-line contacts. Additionally， their primary pores are well-developed， with an average porosity of 17.1 % and an average permeability of 494.317 × 10^-3 μm². The Yacheng 13-1 low uplift primarily exhibits deltaic sandstone reservoirs of the Paleogene Yacheng Formation and the Lingshui Formation. These reservoirs are dominated by medium-to-coarse-grained sandstones， with burial depths ranging from 3 800 m to 4 100 m. They occur in a high-temperature， normal-pressure environment， with grain contacts dominated by linear and concave-convex types， and dissolution pores widely seen within. The Lingshui Formation has an average porosity of 13.5 % and an average permeability of 285.661 × 10^-3 μm²， while the Yacheng Formation shows an average porosity of 9.2 % and an average permeability of 49.158 × 10^-3 μm². The Ya’nan low uplift predominantly exhibits fan-delta reservoirs of the Paleogene Yacheng Formation， characterized by coarse-grained sediment and burial depths ranging from 4 350 m to 4 800 m. They occur in a normal-temperature， high-pressure environment， with grain contacts dominated by point and linear types. What’s more， these reservoirs contain well-developed dissolution pores， with ferruginous cements observed， exhibiting an average porosity of 15.8 % and an average permeability of 107.435 × 10^-3 μm². The discrepancies in sedimentary and diagenetic environments are identified as the primary reason for the differential physical properties among medium-to-deep clastic reservoirs across varying structural zones in the circum-Ya’nan area. Specifically， weak compaction under shallow burial conditions is the major factor contributing to the development of high-quality reservoirs in the Yacheng uplift. In contrast， in the Yacheng 13-1 low uplift， early-stage dissolution and strong compaction act as destructive factors that restrict the formation of high-quality reservoirs. Meanwhile， the overpressure environment resulted from rapid burial during the late stage is the key to the growth of deep， high-quality reservoirs in the low uplift.

Key words: major controlling factor, diagenetic environment, overpressure, clastic rock, medium-to-deep reservoir, Qiongdongnan Basin