A numerical analysis of the single-well steam assisted gravity drainage process (SW-SAGD)

Steam assisted gravity drainage (SAGD) is an effective method to produce he avy oil and bitumen which are important energy resources. In a typical SAGD , approach, steam is injected into a horizontal well located directly above a horizontal producer helping to displace heated oil. Single-well (SW) SAG D attempts to create a similar process using only one horizontal well. To i mprove early-time response of SW-SAGD, it is necessary to heat the near-wel lbore area to reduce oil viscosity and allow gravity drainage to begin. Ide ally heating should occur with minimal circulation or bypassing of steam. W e have investigated early-time processes to improve reservoir heating. A nu merical simulation study was performed to gauge combinations of cyclic stea m injection and steam circulation prior to SAGD in an effort to better unde rstand and improve early-time performance. Results from this study, include cumulative recoveries, temperature distributions, and production rates. It is found that cyclic steaming of the reservoir offers the most favorable o ption for heating the near-wellbore area to create conditions that improve initial SAGD response. More favorable reservoir conditions such as low visc osity, thick oil zones, and solution gas, improved reservoir response. Unde r unfavorable conditions, response was limited.