Horizontal drilling had a high profile from the late 1980s onwards in the tight, fractured reservoirs of the Austin Chalk and the Bakken Shale. Today this technology is being increasingly applied in thin or highly permeable oil reservoirs where there is a need to minimize drawdown to prevent water and gas coning, while at the same time maximizing well productivity.
Horizontal wells have been drilled in relatively thin, high permeability reservoirs such as Helder and Troll in the Dutch and Norwegian sectors of the North Sea respectively. They have been used to improve oil productivity and drainage from the low permeability conglomerates in the North Brae field in the U.K. sector of the North Sea. In Canada, they are being used in the recovery of both light and heavy oil reservoirs, while in Alaska they are being used at Prudhoe Bay to reduce gas coning while maximizing production rates. The world over, from Europe to Argentina to China to Australia, new applications have been found for this production technology barely out of its infancy.
This paper reviews both the theoretical and practical planning considerations necessary for a successful application of horizontal wells. The use of horizontal wells in reservoirs with gas or water coning problems is emphasized.