Research on potential exploration strategies for narrow strip sand body in ultra-high water cut period
To further improve the development effectiveness of BS oilfield's Minghua Town formation narrow strip heavy oil reservoir,which primarily consists of distributary river channels,a"linear"well pattern was deployed for development,alternating injections and production along the direction of the river channels.Following the entry into the ultra-high water cut period,the waterflood efficiency along the river channel direction decreased,with a rapid rise in local water cut and overall low recovery rates.This paper addresses the above challenges by systematically analyzing the heterogeneity of narrow strip sand bodies.A model of a typical narrow strip sand body with a flat top and a convex bottom was developed to investigate its seepage characteristics.A seepage coefficient was introduced to quantitatively characterize the proportion of radial flow and linear flow in river channels of varying widths.According to the flow pattern and the conduction pattern of pressure field,the relationship between pressure gradient and seepage distance was established,providing reference for preparing strategies for or excavation.According to the change of flow pattern and pressure gradient in the sand body of narrow strip,the potential exploration strategies of strengthening injection and production,profile control and flooding,interwell encryption and edge encryption are put forward for different channels and channel section.In the field,8 infill wells were drilled,resulting in an initial daily oil increase of 280 tons and a cumulative oil increase of 48.2×104 t,significantly enhancing the development of narrow strip sand bodies and notably increasing the recovery rate.At the same time,23 potential wells are released,which provides a reference for similar narrow strip oil fields to boost oil recovery in ultra-high water cut period.
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