Press Esc to close



For full content view: Log in Now!

  • Wells drilled overbalanced and underbalanced prove UBD value

    T. M. Haselton, R. Kirvelis, G. Pia and T. Fuller

    This article briefly reviews the drilling and production history of the Gargdzai Region of Western Lithuania, and details the underblanced drilling (UBD) program that evolved from close cooperation with the operator, UAB Minijos Nafta (MN), and Weatherford UBS, the lead UB contractor. The discussion overviews the first three-well UBD program starting in 2000 with Wells PS-2, 3 and 4. It then describes in detail drilling / completion of Well AS-1 and introduces the concept of Production Steering and use of MWD data, together with fluid influx data, to steer the well into higher-productivity layers. It also makes unique direct comparisons between overbalanced and underbalanced legs in the same well and reservoir – a direct result of the innovative relationships established during the drilling program. Finally, it discusses the ongoing drilling program that has evolved.

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