利用地震沉积学定量刻画辫状河三角洲砂体——以委内瑞拉MPE-3区块为例

Quantification of braided river-delta sand body based on seismic sedimentology:an example of the Block MPE-3 in Venezuela

以委内瑞拉MPE-3区块Oficina组辫状河三角洲地层为例,将直井、水平井与三维地震资料相结合,通过层序界面地震识别、90°相位转换及地层切片处理,建立了研究区等时地层格架,在三级层序内识别出6个四级层序;利用横向高分辨率的水平井资料标定地层切片的地震沉积学解释方法,识别了心滩砂体内部由冲沟形成的细粒夹层,有效提高了地层切片的解释精度;利用井震联合刻画结果总结了心滩等沉积体的定量特征,建立了心滩长宽、心滩宽度、辫状河道宽度、冲沟宽度间的定量关系。该研究成果为油藏精细开发提供了地质依据。

This paper presents a research of braided river-delta reservoir in the Bock MPE-3,Venezuela.Based on vertical-and horizontal-well and 3 Dseismic data,a sequence stratigraphic framework in the study area is constructed with the seismic sequence boundary,90°-phase transformation,and stratal slices,and 6 fourth-order sequences are identified within the third-order sequence.Using the seismic sedimentology approach such as lateral high-resolution horizontal well data to calibrate stratal slices,fine-grained inter-beds formed by gullies in sand bodies are identified,which effectively improves the slice interpretation accuracy.The paper summarizes quantitative characteristics of sediments such as channel bars with the joint use of well and seismic data,establishes quantitative relationships among channel bar length and width,braided channel width,and gully width,which may provides a solid foundation for the future development.