琼东南盆地梅山组海底扇成因演化特征与勘探建议

梅山组海底扇作为中央峡谷水道之外最引人注目的大型储集体，是琼东南盆地尤其是深水区常规碎屑岩领域下一步最为重要的勘探对象。总结了琼东南盆地各凹陷钻井资料所揭示的梅山组海底扇差异分布现象，通过研究区大陆架发育特征、陆架坡折带发育特征，结合物源供给与优势海流方向，首次从宏观格局解释了琼东南盆地中央坳陷带不同凹陷海底扇发育地质背景的差异及成因，提出乐东凹陷梅山组大型海底扇主物源来自东北方向海南隆起。通过细化中中新世大海退内部次级海平面旋回特征，首次建立了本区梅山组层序充填与海平面旋回的精确对应关系，从层序成因角度厘清了梅山组各期次海底扇发育演化特征与凹陷级别的有利储层展布特征，并据此提出相应的勘探建议，指出乐东凹陷梅山组中—晚期海底扇储层风险低，是梅山组海底扇领域突破的首选区带；陵水凹陷早期海底扇圈闭有效性较好，是梅山组海底扇大规模成藏的有利勘探方向。该研究为梅山组海底扇领域的勘探部署提供了新思路。

Genetic evolution and exploration strategy of submarine fan in the Meishan Formation,Qiongdongnan Basin

As the most striking large reservoir outside the central canyon channel, the submarine fan of the Meishan Formation is the next most important exploration object in the conventional clastic rock field of the Qiongdongnan Basin, especially in the deep-water area. The differential distribution of submarine fans in the Meishan Formation was revealed by the drilling data of various sags in the Qiongdongnan Basin. Based on the exploration of continental shelf and continental slope break in the study area, the provenance and source supply, dominant paleo-current direction, geological background differences and causes of submarine fans in different sags in the central depression of the Qiongdongnan Basin were analyzed in macro-pattern for the first time. It is proposed that the main material source of the large submarine fan of the Meishan Formation in Ledong Sag was from the Northeast Hainan Uplift. By anatomizing secondary sea-level cycles in the Middle Miocene regression, the accurate corresponding relationship between sequence filling and sea-level cycles of the Meishan Formation in this area was established, and the development and evolution of submarine fans in each sedimentation stage of the Meishan Formation and the favorable reservoir distribution at sag level were clarified from the perspective of sequence genesis. Therefore, the corresponding exploration strategies were put forward, from which the reservoir risk of Meishan Formation submarine fan in Ledong Sag was believed low and thus the submarine fan should be considered the first choice for breakthrough in the future exploration. Meanwhile, the early trap of the submarine fan in Lingshui Sag was effective, providing a favorable condition for large-scale reservoir formation of the Meishan Formation submarine fan. This study presented a new insight to the exploration deployment in the Meishan Formation submarine fan.