ABSTRACT

Horizontal drilling has become a key technology used to reduce costs and enhance recoveries from producing reservoirs. Through 2001, commercial databases contained records on 34,777 horizontal wells from 72 countries. Canada (18,005 wells) and the United States (11,344 wells) were the leading countries for horizontal drilling. More than 5400 horizontal wells were recorded outside of North America. Russia, Venezuela, Oman, United Arab Emirates, Nigeria, Saudi Arabia, and Indonesia were the leading countries in terms of numbers of wells.

Although the concept of horizontal drilling emerged in the 1920s, economic viability was not demonstrated until the 1980s, when pilot projects at Rospo Mare field in Italy (1982) and Prudhoe Bay field (1984) and in the Austin Chalk of Texas (1985-1987) achieved three- to fourfold productivity increases with less than twofold cost increases. From a base of 51 wells in 1987, horizontal drilling increased rapidly; it expanded to the world's active producing provinces and peaked during 1997 with 4990 wells.

Horizontal drilling, which increases wellbore exposure to the reservoir, has delivered multiple benefits. Operators have used horizontal wells to revive economic production, to increase and speed recoveries, to reduce costs, and to increase rate of return. These benefits are critical for operators that must cope with increasing competition and volatile oil prices. The objective of this paper is to characterize the global geographic and geologic distribution of horizontal wells and to illustrate some of the benefits of horizontal drilling with examples from key fields and trends.