Dilation start-up has been widely used in Petro-China's Xinjiang oil field as a means of reducing start-up time and enhancing production from its "super" heavy oil reservoirs through the Steam-Assisted Gravity Drainage (SAGD) process. SAGD dilation start-up employs geomechanical dilation mechanisms to achieve these preferred results. Using a short-period of small-volume and high-pressure fluid injection, the dilation start-up facilitates the development of a dilated zone that vertically connects the SAGD well pair and is laterally uniform along the length of the well. This zone allows for more effective heat transfer to the inter-well area through convection than what is achieved through simple conduction during the conventional SAGD steam circulation start-up. In Petro-China's Xinjiang oil field, conventional SAGD start-up requires 10 to 12 months of non-productive steam circulation before oil production can begin. Wells treated with the SAGD dilation start-up can be converted to production after only 2 to 3 months of steam circulation.

This paper presents optimized steam circulation strategies which can be used with the dilation start-up treated SAGD well pairs. Numerical simulations are effectively integrated with field trials to derive best practices for steam circulation after the dilation start-up. The objectives are to get earlier and increased SAGD production as well as enhanced horizontal steam conformance. Operating parameters such as steam injection pressure, rate and pressure difference between the SAGD well pair were found to influence these objectives.

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