奥连特盆地17区块南部差异性构造演化与非稳态油藏

Differential tectonic evolution and a dynamic oil pool in the south of block 17, Oriente Basin

奥连特盆地前陆期是油气成藏的关键期,在东西向持续挤压背景下,经历了多期次的南北向差异性构造演化变形,是该盆地形成非稳态油气藏的主控因素。在对奥连特盆地的前渊轴部区域二维地震资料精细层序边界解释的基础上,通过系统的构造演化和成藏模式演化分析,发现现今简单鼻状构造背景上的、无明显构造圈闭控制的倾斜油水界面非稳态油气藏,其含油气范围受控于较早一期的古背斜圈闭。另外,依据油藏动力学,该区现今的低倾角地层、稠油物性及南北走向的鼻状构造与东西展布的储集砂体的配置关系等因素,均不利于油气的再次运移,从而形成了平面含油气范围与现今圈闭不匹配的非稳态油气藏。

The foreland region of the Oriente Basin,which has suffered multiple stages of differential tectonic deformation under continuous EW compression,is critical for hydrocarbon accumulation and has become a predominant factor for a dynamic oil pool in the basin.This study shows an oil pool in the foredeep axis area of this basin using detailed 2D seismic sequence boundaries with a tilted oil-water contact,which is not controlled by the current simple nose structure but by a paleo-anticline trap from the earlier stage.In addition,reservoir dynamics,such factors as the current low dip formation,heavy oil property,as well as the perpendicular relationship between the NS trending nose structure and the sandstone distribution in the EW direction,are all unfavorable for hydrocarbon re-migration,which has eventually formed a metastable oil pool whose planar oil-bearing area mismatches with the current trap area.