琼东南盆地陵水凹陷13-2区中新统梅山组海底扇空间差异性及其优质储层分布规律

Spatial differentiation of submarine fans and distribution patterns of high-quality reservoirs in Miocene Meishan Formation, block 13-2, Lingshui Sag, Qiongdongnan Basin

  • 摘要: 琼东南盆地陵水凹陷13-2区自LS13-C井中新统梅山组获高产气流以来,后续勘探钻井均未取得商业突破。前期勘探实践表明,沉积体系控制下的有利储层相带展布是该区勘探成功的关键。针对13-2区梅山组海底扇研究中存在的空间差异性认识薄弱、勘探方向不明等问题,通过综合利用钻井资料与三维地震数据,结合层序地层学分析、古地貌恢复及沉积微相识别等技术方法,系统揭示了梅二段低位体系域海底扇的沉积空间分异特征及储层发育控制因素。研究结果表明,该区梅山组海底扇主要发育于梅二段低位体系域,依据沉积特征差异可进一步划分为四种类型,即东部沟槽限制型、中部水道化型、西部断控坡折型及朵叶型海底扇。海底扇储层发育受沉积相带与溶蚀改造作用共同控制;其中,发育于F2断层同沉积活动下降盘的西部断控坡折型海底扇,储层发育条件(厚度、物性)及天然气成藏条件较好,应为下一步勘探的首选目标。提出的多级坡折控制下多类型海底扇发育模式,可为琼东南盆地深水海底扇勘探提供理论依据和勘探支持。

     

    Abstract: Since the discovery of high-yield gas flows from the Miocene Meishan Formation in well LS13-C of block 13-2 in the Lingshui Sag, Qiongdongnan Basin, subsequent exploration drilling has failed to achieve commercial breakthroughs. Previous exploration practices indicate that the distribution of favorable reservoir facies belts controlled by sedimentary systems is the key to successful exploration in this area. To address problems such as a weak understanding of spatial differentiation and unclear exploration directions in previous studies of submarine fans in the Meishan Formation of block 13-2, the study integrated drilling data and 3D seismic data, combined with sequence stratigraphic analysis, paleogeomorphology restoration, and sedimentary microfacies identification. The sedimentary spatial differentiation characteristics and reservoir development controlling factors of submarine fans in the low-stand systems tract (LST) of the second member of the Meishan Formation were systematically revealed. The results showed that the submarine fans in the Meishan Formation in this area primarily developed in the LST of the second member, and could be further divided into four types based on differences in sedimentary characteristics: eastern trench-confined type, central channelized type, western fault-controlled slope-break type, and lobate-shaped submarine fans. The development of submarine fan reservoirs was jointly controlled by sedimentary facies belts and dissolution modification. Among them, the western fault-controlled slope-break submarine fan developed in the downthrown block of the synsedimentary fault F2 exhibited favorable reservoir development conditions (thickness and physical properties) and natural gas accumulation conditions, and should be the next primary exploration target. The proposed multi-type submarine fan development model controlled by multi-stage slope-break zones provides a theoretical basis and exploration support for deep-water submarine fan exploration in the Qiongdongnan Basin.

     

/

返回文章
返回