Experimental investigation on the SAGD dilation start-up in shallow heavy oil reservoirs

Abstract

Abstract There are few related researches focused on the steam assisted gravity drainage (SAGD) dilation start-up technology (termed as dilation start-up in this paper), especially with physical modelling experiments. Therefore, in order to better understand the dilation start-up process, several large-scale experiments of SAGD start-up with dual horizontal wells were carried out by using the oil sands from Xinjiang oilfield, northwest China. The dilation process characterized by temperature changes at different positions inside the experimental samples was monitored in real time. The performance differences between dilation start-up and conventional start-up were discussed in detail, and the effects of dilation pressure and dilation time on the dilation process were also studied. The experimental research indicated that dilation start-up can significantly enhance the range of dilation zone and improve the uniformity of dilation zone along the horizontal wellbores. Moreover, it was found that dilation pressure is an essential factor influencing the dilation effect, in that the size and distribution of dilation zone are largely dependent on dilation pressure. The evolution of dilation zone with time shows that a long-time dilation prompts the uniform propagation of dilation zone along the horizontal wellbores.