Summary
Drilling services and oil companies have long been interested in acquiring
the capability of landing a well accurately in a hydrocarbon reservoir and
remaining in it for optimal drainage. Although traditional
logging-while-drilling (LWD) propagation resistivity tools can help to achieve
this goal, their overall effectiveness is not satisfactory because they lack
azimuthal sensitivity. Ideally, geosteering and advanced formation-evaluation
methods, such as anisotropy calculations, require azimuthally sensitive
measurements.
This paper discusses a newly developed propagation resistivity tool that is
designed to be azimuthally sensitive for use in geosteering and formation
evaluation while drilling. It uses the tilted-antenna concept to produce
directionally sensitive measurements that are lacking in traditional LWD
propagation tools. This paper also discusses the theory and the development of
this tool, as well as the experimentation and numerical-modeling data used to
characterize its azimuthal capability. Advanced application algorithms used to
calculate the horizontal and the vertical resistivity (anisotropy calculation),
as well as dipping angle, will be explained in detail. Finally, the paper
presents and discusses field examples to demonstrate that this newly developed
tool is a two-in-one service: geosteering and advanced formation
evaluation.
The azimuthal deep-reading resistivity is shown to bear promise for use in
optimization of well trajectory and well placement and in advanced formation
evaluation while drilling. This newly developed tool is superior to traditional
propagation tools in locating bed boundaries and in keeping the well in the
desired pay zone. In addition to providing traditional
multiple-depth-of-investigation resistivity measurements, this new tool
provides multiple-depth-of-investigation azimuthal resistivity
measurements.
© 2009. Society of Petroleum Engineers
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History
- Original manuscript received:
11 August 2007
- Meeting paper published:
11 November 2007
- Revised manuscript received:
12 August 2008
- Manuscript approved:
1 September 2008
- Published online:
15 April 2009
- Version of record:
15 April 2009
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