HORIZONTAL WELLS AND STEAM-ASSISTED GRAVITY DRAINAGE

Petroleum can be produced more efficiently using horizontal wells instead of conventional wells. For a typical 16 hectare well spacing, the pressure drawdown is as small as one-fifieth of that for conventional wells. In some cases, where coning is a problem in conventional production, horizontal wells allow operation with much less coproduction of the displacing fluid. In the thermal recovery of bitumen and heavy oils, the Steam-Assisted Gravity Drainage process with horizontal production wells allows the systematic sweeping of the reservoir with economic production rates and without steam bypass. This paper described and reviews the application of horizontal wells to the production of heavy crude oils and bitumen by both non-thermal and thermal methods.