SAGD Enhanced Oil Recovery Technology of Vertical Well Assisted Double Horizontal Well in Super Heavy Oil Category-III Reservoir

Due to high viscosity, strong heterogeneity and wide development of interbeds, the development of super heavy oil category III reservoir is very difficult. The main development technology SAGD is affected by interlayer and process conditions, some well groups have some problems, such as low production level of horizontal section, uneven development of steam chamber and slow lateral expansion. SAGD technology of vertical well auxiliary is to improve SAGD development effect by making use of SAGD adjacent vertical well, forming thermal connection between vertical well steam huff and puff and SAGD well group, continuous steam injection of vertical well and expansion of steam chamber scale. Vertical well assisted SAGD can improve the development of steam chamber and increase oil production rate. The selection conditions of auxiliary vertical wells are demonstrated by numerical simulation technology, and the perforation parameters, steam huff puff stage and steam drive stage of vertical wells are optimized considering the interlayer distribution. Finally, it is verified in the actual model. With the aid of vertical wells, the average daily oil production of single well group is increased by 5 t/d, the oil steam ratio is increased by 0.021, and the recovery factor is increased by 6.3%, which effectively improves the development effect. The research results provide technical support for SAGD efficient development assisted by vertical wells in class III super heavy oil reservoirs.