Effect of Barriers on the SAGD Performance Result

The barriers in oil reservoir have great effect on SAGD production. Due to wide existence of interlayers, steam chamber can not move upward freely in perspective of chamber development, and also leads to a longer SAGD production cycle so as to increase the investment risk. Firstly the author studied the distribution and formation reasons of muddy barriers in the Zhong 32 of Windy City oilfield. Steam chamber developing characteristics and steam breakthrough pattern are studied by temperature detection data, historical data and microseismic data fitting dynamic data binding static geologic data. Barriers have three relative position relation with SAGD horizontal well. The order sorted by barrier influence to production from high to low degree: injection well inside barriers, between injection and production wells, above injection well. The results showed that the barrier pattern of Zhong32 is physical barriers, with characteristics of high shale-sand ration, low permeability, poor blocking ability. The horizontal continuous barriers increased steam channeling risks thereby control vapor liquid interface more difficult. Double tubes steam injection and artificial lift can be beneficial for the stable steam chamber operation, increase oil production and decrease water cut. High pressure steam operation increases the opportunities of barriers breakthrough by steam and obtains high oil production per day. The pattern of steam breakthrough in muddy barriers can be divided into bypassing and traversing.