Study on oil and gas filling and migration and accumulation in synclinal reservoir area

Abstract

In recent years, the focus of oil and gas exploration in western Daqing has changed from a single large structural high point packaged reservoir to a diversified complex structural low point syncline reservoir. Such reservoirs are mainly lithologic traps, with complex rules of oil and gas filling, migration and accumulation, and irregular oil-water distribution, resulting in unclear understanding of the formation and distribution of syncline lithologic traps. The typical GLN area dominated by lithologic reservoirs is selected as the research object. The oil and gas filling research under the condition of reservoir forming power is carried out by using the source reservoir pressure difference. Based on the plane distribution of crude oil density, the secondary migration and accumulation rule of oil and gas is studied. It is considered that GLN can contain oil in a large area, but oil and gas can not migrate in a long distance. The low value area of crude oil density is the breakthrough of primary migration and the starting point of secondary migration, and its formation is controlled by the principle of phase potential coupling. The sand body is highly heterogeneous and the oil-water distribution is complex, while the sheet sand is mainly pure oil layer, and the water layer is formed only in the parts far away from the breakthrough and poor physical properties.