ABSTRACT:

In mature developments like the Statfjord field offshore Norway, operators are required to drill an increasing number of directionally challenging side tracks of existing well bores to enhance field economics and efficiently recover in-place reserves. This exercise is extending field life and also helps reduce overall drilling costs. Historical data shows that significant time was lost in the 12–1/4" sections of the Statfjord field when these intervals were drilled using traditional PDC technology. In many cases, PDC bits had to be tripped out and replaced by roller cone bits because they failed to achieve the directional objective. In order to improve the drilling efficiency in the field, a PDC bit with superior operating characteristics was required, specifically:

  1. controllable torque response;

  2. consistent directional behavior;

  3. ability to achieve high rates of penetration.

To achieve this, the operator partnered with a bit manufacturer that introduced a new process to develop an application specific PDC drill bit for the Statfjord field. The process incorporated the analysis of the operations using numerical models in addition to laboratory and field testing.The resulting new PDC design was first introduced to the Statfjord field in January 2001, successfully achieving the set objectives. Over the past two years, this unique technology has been utilized on all three platforms of the field and has reduced the number of BHA's per section by 20%. Additionally the new bit has helped to increase the meters drilled per BHA by 46%, improving the ROP per section by 15% and reducing the cost per meter by 12%. These improvements resulted in a total saving of more than US$530,000 for the operator over fourteen 12–1/4" sections in which close to 21,000m have been drilled

This content is only available via PDF.
You can access this article if you purchase or spend a download.