Stabilized oil production conditions in the development equilibrium of a water-flooding reservoir

Abstract

Water injection can compensate for pressure depletion of production. This paper firstly investigated into the equilibrium issue among water influx, water injection and production. Equilibrium principle was elaborated through deduction of equilibrium equation and presentation of equilibrium curves with an “equilibrium point”. Influences of artificial controllable factors (e.g. well ratio of injection to production and total well number) on equilibrium were particularly analyzed using field data. It was found that the influences were mainly reflected as the location move of equilibrium point with factor change. Then reservoir pressure maintenance level was especially introduced to reveal the variation law of liquid rate and oil rate with the rising of water cut. It was also found that, even if reservoir pressure kept constant, oil rate still inevitably declined. However, in the field, a stabilized oil rate was always pursued for development efficiency. Therefore, the equilibrium issue of stabilized oil production was studied deeply through probing into some effective measures to realize oil rate stability after the increase of water cut for the example reservoir. Successful example application indicated that the integrated approach was very practical and feasible, and hence could be used to the other similar reservoir.

Keywords

Development equilibrium / Oil reservoir / Water injection / Water influx / Water cut / Stabilized production

Acknowledgments

The Authors would like to thank the NSFC (National Natural Science foundation of China) for supporting this article through two projects: the National Science Fund for Young Scholars of China (Grant No. 51304164) — “Research on the pressure dynamics of multiple-acidized-fractured horizontal wells in fractured-vuggy carbonate formations”; and the National Science Fund for Distinguished Young Scholars of China (Grant No. 51525404) — “Fracturing and acidizing in low permeability and tight reservoirs”. The paper was financially Supported by the Fok Ying Tung Education foundation for Young Teachers in the Higher Education Institutions of China (Grant No. 151050). The paper was also financially Supported by a basic research project under Grant No. 2015JY0132 from the Science and Technology Department of Sichuan Province.

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