The principles associated with the Gas-Purge Production System (GPPS) were identified by C-FER in recognition of the need for new recovery techniques to improve both production rates and reserves recovery from heavy oil formations. The single point drawdown and flow-induced pressure losses associated with the practice of placing the pump near the heel of the well can cause non-uniform inflow along the horizontal section, resulting in localized sand production from the region near the heel of the well impacting the recovery potential as a result of sand blockage or premature water breakthrough. Also, elevation variations along the horizontal section can lead to increased flow losses and plugging which can detrimentally alter the inflow profile and possibly contribute to early water breakthrough.

To address the limitations of existing heavy oil horizontal well production systems, C-FER proposed the novel Gas Purge Production System or GPPS. This intermittent gas purge system was seen as having a significant advantage over existing production methods because the GPPS had the potential to achieve a relatively uniform inflow pressure profile and to produce sand from the entire length of the horizontal section.

The GPPS can be configured in several different ways to serve either as a lift method or as a combined inflow zone control/lift system with hardware requirements that vary from simple to relatively complex. With this flexibility in configuration design, the system has potential for application in horizontal wells in: · high sand cut heavy oil operations; · thin zone, water or gas coning situations; and thermal Steam Assisted Gravity Drainage (SAGD) applications. 

The major potential enhancements of GPPS relative to conventional production methods in these applications include:

• the well production system can be engineered to maximize the production rates and recovery of horizontal wells in heavy oil, unconsolidated sandstone reservoirs;
• more uniform inflow may be achieved along the entire horizontal section;
• sand production and well clean-out potential may be enhanced;
• it is a rodless production system;
• coupled with zonal isolation and control, the system will facilitate inflow profile control and provide effective water shut-off or pressure drawdown capability; and
• it may facilitate the implementation of SAGD recovery or other novel EOR techniques through selective control of pressure drawdown or steam injection intervals.

Contact: Todd Zahacy, Senior Consultant, Exploration & Production

Tel: 780.450.8989 x240