Intraformational Bed Influence on Remaining Oil Distribution and Tapping Potential Technology with Horizontal Well in Extrahigh-Water-Cut Reservoir

Abstract

Abstract The main pay of Guantao Formation in Gudao Field is a large-scale thick positive-rhythm channel sand oil layer. At the extra high water-cut stage, the thick oil layer is waterflooded seriously, but the top remaining oil is still enrichment due to influence of reservoir heterogeneity. The research shows that the development effectiveness of tapping the potential with vertical well is bad and the economic benefit is low [1]. If horizontal well is used, the producing degree and the recovery of the remaining reserve can be improved effectively. Among various factors of affecting development effectiveness of horizontal well, the influence of intraformational bed development is much more important. The development of intraformational bed and its control on remaining oil distribution should be understood first, then the technology policy research of tapping the potential with horizontal well was conducted in order to ensure the good development effectiveness with horizontal well. In this paper, the remaining oil distribution features under the different developmental conditions of intraformational bed are expounded in detail, the intraformational bed was divided into two kinds, developed and undeveloped; according to its developmental conditions, the technology policies of horizontal well were studied respectively, and the commensurate design criteria of horizontal well was proposed. The application of the achievements in tapping the potential of remaining oil in thick positive-rhythm oil layer during the extra-high water cut period has achieved preferable effectiveness, which provides reference for that in the same type of reservoir.