Abstract：

The Bohai CFD11-X oilfield reservoirs are bottom water in the lower NgⅢ oil group. All the bottom water reservoirs are developed by horizontal oil wells using natural energy. So far, they have entered the extremely high water content stage. It is urgent to further improve the characterization accuracy of the interlayer, clarify the different types of interlayer and their impact on the distribution of residual oil and provide guidance for the efficient production of the remaining oil in the bottom water reservoirs. In this area, the reality is that the resolution of seismic data is low, drilling data is inadequate and mainly in horizontal wells, so the interlayer and residual oil research on bottom water reservoirs are carried out by combination of static and dynamic data, such as drilling, well logging and production data. The study shows the interlayers mainly are mud sediments in the reservoirs, formed by the flood plain and the top of the river. Under the control of reference surface rotation, due to the degree of river cutting stack, the characteristics of the interlayers are different in the reservoirs. According to the permeability characteristics of the interlayers, the interlayers in the study area can be subdivided into full occlusion interlayers, half occlusion interlayers and no shielding interlayers. The full occlusion interlayers developed in isolated single sandbodies. The dynamic response of horizontal oil wells are characterized by edge water drive. The half occlusion interlayers developed in vertical stacked composite sandbodies. Horizontal oil wells have the characteristics of mixed edge water and bottom water drive. The no shielding interlayer developed in cutting a vertical composite sandbody. The oil reservoir has a strong natural energy and horizontal oil wells show strong bottom water drive characteristics. The bottom water oil reservoirs at the lower NgⅢ oil group are enriched in the remaining oil under the existing horizontal well development network. Longitudinally, for the occlusion of different permeability interlayers, residual oil can be enriched in the top, middle and lower sections of the bottom water oil reservoirs, but the enrichment degree is controlled by the horizontal well and interlayer positions. In the plane, affected by the distribution of the interlayer and the degree of well control, the residual oil is mainly enriched in these areas, such as low well control areas, areas between development wells, local structural high parts and interlayer shielding areas. The research results have successfully guided the exploitation of residual oil in the lower NgⅢ oil group in the Bohai CFD11-X oilfield. The horizontal well placement practice achieved good results in bottom water reservoirs. This study can also be used for the guidance of exploitation of residual oil in similar bottom water reservoirs at home and abroad.

Key words：braided rivers; interlayer; bottom water reservoir; residual oil; horizontal well; Guantao Formation; Bohai Sea

Received： 2022-02-18

Corresponding Authors： zhoujl4@cnooc.com.cn

Cite this article：侯东梅, 牟松茹, 周军良, 张文童, 权勃. 基于动静资料的底水油藏隔夹层刻画及剩余油挖潜研究——以CFD11-X油田NgⅢ下油组 为例. 石油科学通报, 2022, 04: 475-486 HOU Dongmei, MU Songru, ZHOU Junliang, ZHANG Wentong, QUAN Bo. Interlayer and residual oil distribution study based on dynamic and static data: A case from the Lower NgⅢ Formation in the Bohai CFD11-X oilfield. Petroleum Science Bulletin, 2022, 04: 475-486.

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