“富砂型”浅水三角洲储层预测及其油气成藏模式分析——以渤海西部沙垒田凸起明下段为例

Reservoir prediction of "rich sand" shallow delta and hydrocarbon accumulation pattern analysis——A case of Shaleitian salient lower member of Minghuazhen in the western Bohai sea

渤海西部沙垒田凸起明下段发育"富砂型"浅水三角洲沉积,与传统浅水三角洲沉积不同,"富砂型"浅水三角洲沉积具有砂岩百分含量高,砂体厚度范围广,纵向上砂体叠置关系复杂,横向上砂体变化快的特点,采用常规的储层预测方法难以准确刻画出砂体的纵横向叠置关系。以地震沉积学理论为引导,通过创新思路,首先引入分频反演的方法,合理利用高分辨率地震资料中的高、中、低频信息,减少薄层和厚层反演的不确定性,从而得到高分辨率的反演结果;然后以分频反演为依托,采用地层切片的地震属性综合分析方法,系统研究了明下段"富砂型"浅水三角洲的储层横向分布规律。储层分布规律的差异形成不同的油气成藏模式,明下段下油组油气成藏主要受"脊-断-砂"三因素耦合控制,断层主要控制了油气的横向、纵向运移;明下段上油组油气在沿断层运移的同时也沿砂体横向运移,形成"富砂型"浅水三角洲特有的"之"字型油气成藏模式。

"Rich sand"shallow delta deposition develop in Shaleitian salient lower member of Minghuazhen of western Bohai sea.With the traditional shallow water delta deposition is different,"Rich sand"shallow water delta deposition having a high percentage of sandstone,a wide range of sand thickness,vertical stacking sand on complex relationships,the lateral sand changes quickly.Reservoir prediction method using a conventional aspect is difficult to accurately portray the sand vertical and horizontal stacked relationship.Seismic sedimentology theory guided by innovative ideas,first introduced division inversion method,rational use of high,medium and low-frequency information in the high resolution seismic data,reduce thin and thick inversion uncertainty,then obtain a high-resolution inversion results.Then based on the frequency-divided inversion,using the strata slice of seismic attribute analysis method,systematic study of the lower member of Minghuazhen"rich sand"shallow water delta reservoir lateral distribution.The difference of reservoir distribution law forms different hydrocarbon accumulation pattern.The oil and gas reservoirs in the lower part of Minghuazhen are mainly controlled by the three factors of"spinal-broken-sand".The faults mainly control the horizontal and vertical migration of oil and gas.The under part of Minghuazhen oil and gas migration are along faults at the same time along the sand lateral migration.The pattern forms'rich sand'shallow water delta unique"and"font hydrocarbon accumulation.