Steam conformance investigation of flow control devices deployed in SAGD injection and production horizontal wells

Abstract

The nonuniformity of the steam chamber has a significant influence on oil recovery in the process of Steam-Assisted Gravity Drainage (SAGD). To improve steam conformance, Flow Control Devices (FCDs) are generally installed in both the SAGD injector and producer. In this paper, we investigated the steam conformance of tubing-deployed FCDs in a SAGD well pair. First, a three-phase, three-dimensional reservoir model was developed. Then, a wellbore model for saturated steam flow in the FCD equipped injector and oil/water flow in the FCD equipped producer was proposed. Next, the reservoir and wellbore models were coupled and solved fully implicitly. Finally, after model validations, the effects of the steam injection mode, FCD parameters, steam injection parameters and reservoir geological properties on the conformance of the steam chamber were studied. The results showed that tubing-deployed FCDs were obviously better at improving the steam conformance than the simultaneous dual-tubing string injection technique and injecting steam at only a single point. The steam chamber conformance increased with a decrease in steam injection pressure and reservoir permeability and an increase in steam quality and oil saturation. The steam chamber uniformity gradually declined with time. To maintain the steam conformance over the life of the SAGD and ultimately oil recovery, the FCD open flow area design in SAGD wells should be adjusted at different injection times. When the FCD open flow area was small in the part with high permeability and large in the part with low permeability, a high degree of steam conformance and greater amount of cumulative oil production could be obtained.