裂缝性稠油油藏蒸汽吞吐产能预测模型

A Model for Productivity Prediction of Fractured Heavy Oil Reservoir in Cyclic Steam Stimulation

针对裂缝性油藏为裂缝-孔隙型双重介质且加热区内地层温度为非等温分布,在常规稠油油藏蒸汽吞吐加热半径计算模型的基础上,通过引入加热区前沿温度,构建了考虑地层温度为非等温分布的裂缝性稠油油藏蒸汽吞吐加热半径计算模型,并基于天然裂缝等效渗透率张量理论,将裂缝性油藏变换成等效各向同性油藏,最终推导出裂缝性稠油油藏蒸汽吞吐产能预测模型。以某裂缝性稠油油藏为例进行了计算,结果表明,本文产能预测模型计算结果与裂缝性双重介质热采数值模拟计算结果基本吻合,从而验证了本文模型的准确性。敏感性分析表明,蒸汽吞吐加热半径是加热区前沿温度的函数,加热半径随前沿温度的降低而增大,产量随裂缝孔隙度的增加而增大。

In view of the characteristics of pore-fracture dual media of the fractured reservoir and the non-isothermal character of the distribution of the formation temperature in the heating area, we have developed a heating radius model of fractured heavy oil reservoir by the introduction of the front temperature of heating area based on the conventional heating radius model. Based on the equivalent permeability tensor thery in naturally fractured reservoir, the fractured reservoir was equivalent to an isotropic reservoir, and finally the productivity prediction model of fractured heavy oil reservoir in cyclic steam stimulation was built. A fractured heavy oil reservoir is taken as an example to prove the new model. The study shows that the calculation result of the new productivity prediction model is in good agreement with that of the dual media numerical simulation for the same parameters from the same reservoir, which verifies the effectiveness of the model. Sensitivity analysis indicates that the heating radius of steam huff and puff is the function of the front temperature of heating area, and that the heating radius increases with the decrease of the front temperature while the oil production increases as the fractured porosity increases.