浅水三角洲分流砂坝储层构型研究

Dealing with the difficulties in identifying the genetic types of distributary bars in shallow delta and developing the remaining oil at the high watercut stage, we suppose to measure the modern sediments by analyzing satellite images and trial trench, to build the quantitative architecture model of distributary bars, including the exterior geometry shape, inner architecture and the overlapping patterns. Thus the genetic types and deposition process of distributary bars can be revealed. Based on the quantitative architecture model, the conceptual model can be built by architecture analyses in dense well spacing zone. Accordingly, numerical simulation and physical simulation experiments are designed to discuss the impact of the inner architecture on the fluid flow, to explore the genetic mechanism and distribution pattern of remaining oil under the influence of architecture as well as development engineering factors, which will provide the geological theoretical basis of EOR research, and is of great practical significance for sustainable development of the oil industry and even the national economy. At the same time, it has great theoretical significance for the sedimentology of shallow deltas and the oilfield subsurface geology.

本项目拟针对浅水三角洲分流砂坝成因类型不清以及该类油藏高含水期剩余油挖潜难的问题，拟对现代沉积进行测量（卫星照片分析，实地考察与探槽测量），建立分流砂坝的外部形态、内部结构以及相互叠置关系的定量构型模式，探索分流砂坝的成因类型及沉积过程。并在该模式的指导下，对地下小井距区进行构型精细解剖研究，构建该类储层的概念模型。基于概念模型进行数值模拟和物理模拟实验，探讨分流砂坝内部构型对油水运动的影响，揭示分流砂坝构型与开发工程因素共同作用下的剩余油形成机理与分布模式，为提高该类油藏采收率提供地质理论依据。这对于我国石油工业乃至国民经济的可持续发展具有十分重大的现实意义。同时，这一研究对于浅水三角洲沉积学与油藏开发地质学的发展也具有较大的理论意义。

陆相湖盆断陷期发育的浅水三角洲沉积，是中国东部老油田重要的储层类型之一。储层内部构型控制的剩余油已成为该类油田挖潜的主要目标，迫切需要对该类地下储层开展构型分析工作。但目前对陆相湖盆断陷期三角洲前缘储层的认识主要集中于复合砂体层次，其内部构型模式是尚未解决的科学问题，这也极大地制约了该类储层的进一步开发。因此，本项目选取鄱阳湖等6个典型河控三角洲现代沉积为考察对象，对其三角洲前缘沉积各类构型单元及其相互关系进行定量描述，建立了单一微相级次的定量构型模式。水下分流河道向湖盆方向宽度变窄、数量变多，呈发散叶脉状；单一河口坝呈三角状和狭长心滩状，河口坝长度与宽度之间存在较好的线性关系。进而，选取大庆油田小井距区为地下构型解剖对象，采取现代沉积定量描述与地下储层构型解剖相结合的思路，探索陆相湖盆断陷期浅水三角洲储层内部构型模式。