Schlumberger

Technical Paper: Well Placement Using Borehole Images and Bed Boundary Mapping in an Underground Gas Storage Project in Italy

Society: Other
Paper Number:
Presentation Date: 2011
 

Abstract

Multiple underground gas storage horizontal wells were drilled in 2008, 2009 and 2010 in Italy in several different fields. The wells were steered to maximize sand exposure in the target formations using a bed boundary mapping tool and borehole images. The wells were first landed based on offset pilot holes and a bit resistivity measurement. After the casing was run the production section was steered to total depth.

Horizontal well drilling in Italy is challenging even for short horizontal wells because formations include steep dips, faulting and stratigraphic changes. Steering information was used in real-time by the geosteering team to overcome these issues and optimally place the wells and maximize the exposed permeability. This paper will more closely examine wells from two different fields to show how the real-time data were applied by the steering team to drill successful wells. The real-time data allowed a more optimized landing, maintenance in zone of interest, exit prevention and accurate detection of dip and the presence of shoulder beds.

Steering results were verified after drilling using wireline magnetic resonance on drillpipe. Procedures were changed iteratively for each well to improve performance. By using the bed boundary mapping measurements and borehole images the geosteering team avoided sidetracks and steered these wells successfully to total depth. Without this information realtime decision making would have been more difficult and postwell interpretation less clear.

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