Alternative water flooding method in multi-layer sandstone reservoir near limit water cut stage

Abstract

The invention provides a similar limit water cut period take-turn water drive method for a multi-layer sandstone reservoir. The method includes the steps that a geological model based on single-cause sand bodies is established; on the basis that the geological model based on the single-cause sand bodies is established, a remaining oil distribution model based on the single-cause sand bodies is established; the single-cause sand bodies similar in property are combined into cause sand body sets; according to the reservoir characteristics of different single-cause sand body sets in a layer system and the remaining oil distribution conditions, the corresponding vectorization water drive adjustment scheme is determined; take-turn water drive based on the single-cause sand body sets is performed. With the similar limit water cut period take-turn water drive method for the multi-layer sandstone reservoir, influences of the heterogeneity of reservoir stratums of the multi-layer sandstone reservoir on water drive development can be reduced to the maximum, comprehensive displacement and balance displacement in a plane in the longitudinal direction of the single-cause sand bodies are achieved, and therefore a high-strength and high-efficiency water driving flow field can be established, and water drive sweep efficiency and water drive recovery efficiency can be improved substantially.

Description

technical field [0001] The invention relates to the field of oil field development, in particular to a method for alternate water flooding in the near-limit water-cut period of a multi-layer sandstone reservoir. Background technique [0002] Multi-layer sandstone reservoirs are the main type of continental sedimentary reservoirs in my country, most of which belong to the fluvial-delta depositional system, with many oil-bearing small layers and serious reservoir heterogeneity, resulting in interlayer, intralayer, and plane contradictions It is the main factor affecting the effect of water flooding development. Since the reservoir architectural structure research method was proposed and applied to underground reservoir research in the 1980s, it has been found that each small layer in a multi-layer sandstone reservoir is a compound-genetic sand body with a complex internal structure, composed of multiple single-genetic sandstones. The body is combined in the way of vertical sup...

AI Technical Summary

Problems solved by technology

Since the current well pattern adjustment technology uses the development layer as the basic deployment unit and water flooding development unit, the layer well pattern needs to take into account the development of multiple small layers in the layer and single-origin sand bodies, and cannot target each single-origin sand body. Vectorized adjustment of displacement intensity in different water flooding directions based on plane heterogeneity of volume

Therefore, the well pattern adjustment based on the development layer is difficult to solve the plane contradiction, and the plane water flooding sweep coefficient needs to be further improved

[0004] Due to the limitations of the above-mentioned water flooding development technology, it is difficult to greatly increase the recovery rate of water flooding oilfields

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