An experimental study to quantify sand production during oil recovery from unconsolidated quicksand formations

To obtain a comprehensive understanding on sand production and main factors affecting sand production in unconsolidated quicksand oil reservoirs during their production stage, the sand production processes under different conditions have been modelled. The modelling experiment was carried out on unconsolidated sand formation model made of water washed white sand, clay (kaolinite) and distilled water, by using a newly developed sanding modelling apparatus. The effects of drag force acting on the formation and formation cementation on sand production were analysed. The experimental results show sand and oil production rates both increase with the rise of drag force acting on the formation and decrease with the increase of cement content, and the sand production rate even approaches zero at high cement content. The reservoir with higher pressure is more likely to produce sand during development due to higher drag force, and drag force and effective formation stress jointly affect oil production. Therefore, the sand production rate can be estimated according to clay content, and proper sanding prevention measures can be taken correspondingly. In some cases, sand production in oil reservoirs can be much greater than that in gas reservoirs.