蒸汽辅助重力泄油（SAGD）是一种高效开发稠油的热采技术。针对加拿大长湖油田原油黏度大，砂泥互层状隔夹层渗透率低、厚度大，隔夹层上方原油动用难度大等问题，进行了不同渗透率、不同温度下的稠油启动压力梯度室内实验，分析原油在重力作用下通过隔夹层的可行性。在此基础上，开展了3组SAGD二维物理模拟实验，研究了砂泥互层状隔夹层厚度对SAGD蒸汽腔扩展及生产效果的影响，确定砂泥互层状隔夹层条件下SAGD蒸汽腔扩展厚度界限。结果表明：在油砂开采过程中，稠油在隔夹层中的流动存在启动压力梯度现象，只有当隔夹层上方地层中的温度达200 ℃以上，原油黏度降至8.966 mPa·s以下，隔夹层上方的原油才能单纯依靠重力作用开始流动；随着地层中砂泥互层状隔夹层厚度增大，蒸汽腔呈现纵向扩展减弱、横向扩展增强，蒸汽突破隔夹层能力减弱的趋势。砂泥互层状隔夹层渗透率为50 mD，厚度低于6 cm时，蒸汽突破隔夹层，隔夹层上方原油能得到部分动用。
Steam-assisted gravity drainage（SAGD）is a thermal recovery technology for the efficient development of heavy oil reservoirs. The Long Lake Oilfield in Canada is faced with problems such as high viscosity of crude oil，low permeability and large thickness of the sand-mud interbed，and difficult crude oil production above the interbed. In response，laboratory experiments on the start-up pressure gradient of heavy oil at different permeability and temperature were carried out. The feasibility of crude oil passing through the interbed under gravity was analyzed. On this basis，three sets of two-dimensional SAGD physical simulation experiments were carried out to study the influence of the thickness of the sand-mud interbed on the expansion of the SAGD steam chamber and the production effect of SAGD and obtain the expansion thickness limit of the SAGD steam chamber under the condition of the sand-mud interbed. The results show that the flow of heavy oil in the interbed has a start-up pressure gradient in the process of oil sand exploitation. The crude oil above the interbed will start the flow merely by gravity only when the temperature in the formation above the interbed reaches 200 ℃ or more and the viscosity of the crude oil decreases to below 8.966 mPa·s. The steam chamber shows a trend of the vertical expansion weakening，the horizontal expansion increasing，and the ability of the steam to break through the interbed declining as the thickness of the sand-mud interbeds in the formations increases. The steam can break through the interbed and the crude oil above the interbed can be produced to a certain extent when the permeability of the sand-mud interbed is 50 mD and its thickness is less than 6 cm.