精细地震层序地层分析技术及应用——以渤海湾盆地歧口凹陷滨海地区为例

High-precision analysis technology of seismic sequence strata and its application: A case study of Binhai region in Qikou Sag,Bohai Bay Basin

常用的层序地震解释技术不能对体系域内部沉积体的空间展布及叠置样式进行解释,难以建立严格意义上的等时层序地层格架,等时地层切片难以实现。针对这一技术难题,采用地震反射结构精细处理的地震小层自动追踪技术,准确识别出三级层序界面及体系域边界,并对Wheeler域中表现出的沉积旋回变化进行精细标定,弄清各体系域内部砂体的展布规律,最后落实岩性圈闭。采用该项技术,重新厘定了歧口凹陷滨海地区古近系SSQ2内各三级层序的层序界面、最大湖泛面及初始湖泛面,进行"三面"约束储层反演,在低位体系域发现多个低位扇体等岩性圈闭,均取得了良好的钻探效果。

Common technology of seismic interpretation on sequence strata has much limitation. For example, the space distribution and imbricate pattern of sedimentary units within system tract can not be interpreted. Also, strictly speaking, it is hard to establish isochronous stratigraphic sequence framework. The strata slices which are of isochronous meaning are difficult to achieve. In order to resolve these problems, this paper adopts a new seis- mic interpretation technology of sequence strata to identificate the boundary of sequence and system tract, and to calibrate and demonstrate the variation of deposition cycle displayed in Wheeler domain, and to clarify the distri- bution law of sand, and finally to identify lithologic trap. This paper confirms the maximum flooding surface, first flooding surface and sequence boundary by the technology in Binhai region of the Qikou Sag, and progresses constrained seismic inversion, and finds many lithologic traps in LST. The practical application of this technology has been proved feasible and efficient.