Review of Horizontal Drilling

Petroleum Development Oman (PDO) has drilled 350 horizontal wells in the past 8 years in 33 different oil and gas fields. Since the first wells were drilled the technology and its applications have evolved considerably. The paper describes that rapid evolution using four fields as examples. There has been a diversification of well designs as the authors have learnt how to tailor horizontal drilling most effectively to different situations. In many cases wells can be drilled faster and cheaper than 5 years ago, but there are also examples where more elaborate designs have been applied. The geological targeting and evaluation of the wells has also improved. Further evolution is planned with the next step likely to be the wider use of multi-wellbore horizontals.