【摘要】 针对具有一定厚度的、整装的特稠油油藏,蒸汽辅助重力泄油(SAGD)相比于其他热采方法,开发效果更好。目前研究认为SAGD主要通过重力机理开采稠油而忽略了注采压差对SAGD开发的影响,导致矿场预测误差较大。本文针对这个问题,对SAGD生产过程中的注采压差进行了详细研究,基于加拿大Mackay River和Dover区块地质参数,建立地质模型,研究了注采压差对采油速度、SAGD开发稳产时间、蒸汽腔上升阶段及蒸汽腔横向扩展阶段的影响。结果表明:注采压差在SAGD开发过程中起重要作用,随着注采压差的增大,采油速度呈现先快速增加后增速变缓的趋势;在蒸汽腔上升初期,腔体呈扇形,一段时间后呈近似六边形;蒸汽腔到达油层顶部并不一定出现最大泄油速度,最大泄油速度一般在蒸汽腔到达油层顶部一段时间之后出现;注采压差影响着蒸汽腔上升扩展角的变化,而扩展角决定着蒸汽腔上升时的波及范围;注采压差在蒸汽腔上升阶段起着重要作用,而在其横向扩展阶段作用开始减弱。因此在现场实践中,SAGD生产前期可以适当的提高注采压差,而在蒸汽腔横向扩展阶段适当的减少注采压差,这样可以降低发生汽窜的概率,从而达到最优经济效益。更多还原

【Abstract】 Steam-Assisted Gravity Drainage(SAGD)provides many advantages compared to alternate thermal recovery methods for bitumen, especially for thick and intact reservoirs. Nowadays, most researchers believe that the gravity mechanism is the main driver in SAGD recovery, ignoring the injector-producer pressure difference, which makes the field prediction deviates from reality. To study this problem, this paper makes further investigation into the injector-producer pressure difference. Based on the geological parameters from the Mackay River and Dover reservoirs in Canada, a numerical geological model is established. Meanwhile, the effects of pressure difference on oil production rate, stable production time, rising steam chamber and steam chamber expansion were studied in depth. The results indicate that the pressure difference has a great impact on SAGD recovery and with increasing pressure difference, the oil production rate also increases, but the increasing trend is reduced. At the beginning of the rising steam chamber stage, the steam chamber is fan-shaped, and sometime later, the fan-shaped chamber becomes a hexagon chamber. The steam chamber reaching the cap-rock does not mean it will show the greatest oil production rate. Pressure difference plays an important role on the steam chamber expansion angle, and the expansion angle has a great influence on the steam spreading range. The pressure difference has a significant impact on the steam rising stage, but at the steam expansion stage, its impact declines, so in the field, at the beginning of the SAGD recovery, it is better for us to increase the pressure difference and in the steam expansion stage, we can decrease the pressure difference to some degree, to avoid steam breakthrough and to improve economic returns.更多还原