Press Esc to close



For full content view: Log in Now!

  • Omani field tests compare UBD to conventional drilling

    M. S. Culen, S. Al-Harthi and H. Hashimi

    Utilization of underbalanced drilling (UBD) at Petroleum Development Oman (PDO) stretches back to sporadic projects in the mid-1990s. However, not until recently were tangible gains realized using this technique. Although UBD’s benefits are widely accepted within North America, the technology has not been fully exploited internationally for several reasons, particularly justification of increased drilling costs against perceived “intangible” benefits. Such justification is particularly hard for asset managers and well planners to make in the absence of concrete industry data on production increases.

This area of the site is restricted. In order to gain access, please either Log In, or subscribe to World Oil.

Two options are available to you for creating an account.

1. Get a Free Trial Subscription to World Oil Magazine and gain immediate access to select content on World Oil Online.

Start a Free Trial Subscription and gain immediate access to the complete current issue of World Oil Magazine. Plus, you’ll receive 3 upcoming issues of World Oil Magazine in print or digital format.* You also receive access to the Energy Events Calendar, Industry Statistics and WO Wire’s news and industry coverage.

Free Trial

2. Purchase a subscription to World Oil magazine and gain immediate and complete access to World Oil Online. As a Total Access subscriber you will have access to all areas of the site available to registered users and free subscribers as well as having access to such premium content areas as:

  • The Archives section containing over ten years of complete magazine archives,
  • The WO DataHub's engineering tables and directories,
  • The World Oil annual forecasts, including past predictions,
  • Select World Oil technical handbooks,
  • And much, much more!


Physical copies of this content may be available for purchase. Visit the Reprints & Back Issues section.

If you are already a paid subscriber and do not have access, please email



Engineering Data Tables

World Oil's specialized upstream Engineering Data Tables featuring the Drill Bit Classifier, Tubing Tables and more. Get Total Access today.


2013 Fracturing Technology

2013 Fracturing Technology