Tight oil is the accumulation of oil trapped in the shale formation or transported to the interlayer in a very short distance. Tight oil has a broad prospect of exploration and development and has become an important replacement resource for conventional oil resources. The evaluation of structural characteristics of tight oil reservoirs is the hot spot and frontier of tight oil research. However, tight oil resources are formed uniquely, and their characteristics are different from those of conventional oil resources. The study on the structural characteristics of tight oil reservoirs is helpful to deepen the scientific understanding of tight oil reservoir systems. This paper reviews the main progress made in the evaluation of structural characteristics of tight oil reservoirs in recent years. The purpose of this paper is to deepen the systematic understanding of tight oil reservoir structure and enrich the understanding of the occurrence law and enrichment mechanism of tight oil resources, to promote the geological evaluation, exploration, and development of tight oil resources.

View full abstract

Oilfield water drives through the injection of water into the reservoir, using water to drive out the crude oil in the reservoir. Unstable waterflooding is a method of water-drive development. Unstable waterflooding is one of the important means to improve oil recovery when continuous waterflooding is difficult to establish an effective displacement effect of the oil layer. At present, more and more oilfields have entered the middle and high water cut stage, and the proportion of reservoirs with low permeability and low abundance is getting higher and higher, which makes oilfield development more difficult. The research on the development mechanism of oil field water drives, including unstable waterflooding, is one of the research focuses of oil field water flooding development. This paper reviews the present situation of oil recovery technology for unstable waterflooding in recent years, including laboratory experiments and field applications. Furthermore, combined with the latest research progress in recent years, the development trend of unstable waterflooding technology is discussed. The purpose of this paper is to deepen the understanding of the oilfield waterflooding development system and enrich the understanding of the mechanism of unstable waterflooding to promote the effective development of oil resources.

View full abstract