Patent ID: 8905132
Filing Date: 2014-12-09
Classification: E21B

Abstract:
1. A method of establishing fluid communication between a well pair in an oil-sand reservoir during a startup stage of a steam assisted gravity drainage process, the reservoir comprising dilatable oil sands forming a barrier to fluid communication between the well pair, the wells in the well pair each having a section that extends substantially in a horizontal direction of from about 500 m to about 1500 m in length, the substantially horizontal sections of the wells being substantially parallel and spaced vertically apart by from about 3 m to about 8 m, and wherein fluid communication is established in an inter-well region between the substantially horizontal sections, the method comprising: a) circulating steam within a well of the well pair to apply a steam pressure to a region of the oil sands adjacent to the well and to heat the inter-well region by conduction to achieve a substantially uniform temperature distribution along the horizontal section of the well within about 2° C. of steam injection temperature, wherein said circulating steam within the well comprises injecting steam into the well and producing steam from the same well; b) while circulating steam within the well at a substantially steady state, increasing the steam pressure to a dilation pressure sufficient to dilate the oil sands in the region of the oil sands adjacent to the well, but below a fracture propagation pressure sufficient to create open channels of direct fluid communication between the wells, thereby producing a dilated region; c) while circulating steam within the well at a substantially steady state, maintaining the steam pressure at a level sufficient to enlarge the dilated region but below the fracture propagation pressure, until detection of a signal indicative of fluid communication between the well pair; and, d) while circulating steam within the well, expanding the dilated region along the length of the horizontal section so that the inter-well region is dilated without significant fracturing.