Abstract: A check valve structure includes an engaged portion including a hole for ventilating fluid between one side and another side of the engaged portion, and a hole plug. The hole includes a locking hole and a ventilating hole outwardly circumferentially arranged around the locking hole. The hole plug includes a locking portion inserted in the locking hole to lock the locking portion therein and an outer portion outwardly circumferentially extending from the locking portion to cover the ventilating hole such that the fluid flows in a direction from the one side to the another side, and is prevented from flowing in a direction from the another side to the one side.

Abstract: A method of establishing fluid communication between a well pair in an oil-sand reservoir, where dilatable oil sands in the reservoir form a barrier to fluid communication between the well pair. Steam or water is circulated within at least one well to a region of the oil sands adjacent to the well. The steam or water pressure is increased to a dilation pressure sufficient to dilate the oil sands in the region. While circulating steam or water within the well at a substantially steady state, the steam or water pressure is maintained at a level sufficient to enlarge the dilated region, until detection of a signal indicative of fluid communication between the well pair. The rates and pressures of steam or water injection and production may be monitored and adjusted to vary a bottom-hole pressure in the well.

Abstract: A tool for releasably coupling a coiled tubing string to a primary tubing string includes: a tool body for coupling to a downstream end of the primary tubing string, the tool body comprising a locking mechanism for selectively coupling a coiled tubing end joint to the tool body, the locking mechanism being unlockable in response to fluid pressure inside the tool body exceeding a first threshold; a wellbore access mechanism openable in response to fluid pressure inside the tool exceeding a second threshold.

Abstract: A method of establishing fluid communication between a well pair in an oil-sand reservoir is provided, where dilatable oil sands in the reservoir form a barrier to fluid communication between the well pair. Steam or water is circulated within at least one well to apply a steam or water pressure to a region of the oil sands adjacent to the well. The steam or water pressure is increased to a dilation pressure sufficient to dilate the oil sands in the region. While circulating steam or water within the well at a substantially steady state, the steam or water pressure is maintained at a level sufficient to enlarge the dilated region, until detection of a signal indicative of fluid communication between the well pair. The rates of steam or water injection and production may be monitored and adjusted, and the steam or water pressure may be controlled by adjusting the rate of steam or water injection or production to vary a bottom-hole pressure in the well.