涠洲12-A油田流二段Ⅱ油组沉积特征及演化

Sedimentary Characteristics and Evolution of the 2nd Oil Series in the 2nd Member of Liushagang Formation in Weizhou12-A Oilfield

北部湾盆地涠西南凹陷涠洲12-A油田流沙港组二段Ⅱ油组构造复杂,沉积差异大,横向变化快,对物源和沉积相的认识存在争议。通过测井、岩壁芯和地震等资料的分析研究,明确了涠洲12-A油田流沙港组二段Ⅱ油组物源来自于西南方向的涠洲12-8构造脊;划分了2长期基准面旋回、3个中期基准面旋回,建立了相应的等时层序格架;通过分析不同油组的沉积特征差异,识别出了两种沉积相,其中底部为扇三角洲沉积,顶部为正常三角洲沉积;并从基准面旋回的角度探讨了其沉积模式和演化规律。

The structure and sedimentary characteristics of the 2nd oil series in the 2nd Member of Liushagang Formation in Weizhou12-A oilfield,Weixinan depression,Beibu Gulf basin were very complex. Based on the analysis of the data of well logging,core and seismic data,it is obvious that the provenance of the 2nd oil series in the 2nd Member of Liushagang Formation in Weizhou12-A oilfield is from the southwest Weizhou 12-8 structure ridge; two long-term base level cycle and three medium-term base level cycles were divided,isochronous sequence stratigraphic framework was established; two sedimentary facies were identified by analyzing the differences of sedimentary characteristics of different oil group,the bottom of the 2nd oil series developed fan-delta depositional system,the top developed normal delta depositional system; the evolution sedimentary characteristics was discussed from the aspect of base level cycle.