The feasibility study on high pressure steam flooding after water flooding of common heavy oil reservoir

The common heavy oil reservoir in Shengli oilfield usually has deeper buried depth andthe reservoir pressure and water cut are both high after long-term water flooding, which makes it difficult to carry out steam flooding after water flooding. In this paper the effects of reservoir pressure and steam quality on steam heating reservoir and steam expansion are studied based on the numerical model; the feasibility of high-pressure steam flooding is also demonstrated. Finally, the development result of high-pressure steam flooding is validated through the field practice in Gudao Oilfield Zhong’er’zhong Ng5 pilot test area. The research result shows that when reservoir pressure is constant, the greater the steam quality, the more the carried heat, the more sufficiently the steam expands in vertical and horizontal directions, the faster the temperature front and gas saturation front move, the larger the heating radius. If the steam quality is constant, the greater the reservoir pressure, the higher the steam chamber temperature, the more slowly temperature front and gas saturation front move, the smaller the heating radius. With enhancing the steam quality and taking advantage of its high specific volume and enthalpy, the high-pressure steam flooding can resolve the problem of small steam chamber caused by high reservoir pressure so as to achieve the same development effect of low reservoir pressure and low steam quality, namely the function of “equal specific volume and equal effect”.