琼东南盆地中东部三亚组层序构成及有利区带预测

三亚组为琼东南盆地中东部②号断裂带地区重要的勘探目的层段之一.运用地震资料并结合钻井等其他资料, 将三亚组划分为2个三级层序: S₆₀—S₅₂、S₅₂—S₅₀, 并指出这2个层序发育的背景为挠曲双陆架坡折型.其中S₆₀—S₅₂层序表现出断拗转换阶段的特征, S₅₂—S₅₀层序则为隐伏断裂控制的挠曲坡折的特征.层序内体系域的发育受上述层序地层格架的控制, 下切谷、斜坡扇等低位体在S₆₀—S₅₂层序内较发育, 前积楔、斜坡扇等低位体在S₅₂—S₅₀层序内较发育.2个层序内海侵和高位体系域均受双坡折带控制, 并可划分出滨浅海陆架、陆坡和深海-半深海等沉积体系.指出了②号断裂带三亚组内的有利勘探区带. 

Sequence Architecture and Favorable Reservoir Prediction of Sanya Formation in the Central and Eastern Qiongdongnan Basin

The Sanya Formation is one of the most important exploration layersin the area ajacent ② fault belt, central and eastern Qiongdongnan basin. The Sanya Formation can be divided into two third-order sequences (S₆₀-S₅₂, S₅₂-S₅₀) based on the integrated analysis of seismic and logging well data. The sequence of S₆₀-S₅₂ is formed on the beginning of thermal subsidence after rifting. This sequence and overlying one of S₅₂-S₅₀ are characterized by occurrence of the flexural slope-break, which is controlled by deep buried faults. Two slope-breaks constrain the development of system tracts in third-order sequence. Incised valley and slope fan are observed commonly in lowstand system tracts(LST)of the S₆₀-S₅₂ sequence, progradational wedge and slope fan occur widely in LSTof the S₅₂-S₅₀ sequence. Depositional systemsin transgressive system tracts and highstand system tracts are also controlled by double shelf slope-break zones which are taken as the boundary of different depositional systems from littoral shelf to continental slope, bathyal sea to deep sea. The results suggest that the Sanya Formation near the ② fault belt taken as the slope break zone is a favorable area for hydrocarbon exploration.