Severe surface vibrations and noise were significant operational and environmental concerns when drilling conglomerates and marl in the 17 ½” top hole section with a roller cone bit in the Austrian part of the Molasse Basin. To improve on the situation the major operator in the area, RAG decided to run an Anti Stick-slip Tool. The BHA was not changed from previous wells other than including the AST. This gave a good basis for pinpointing the effect from the tool.
The AST tools were run in multiple wells with the same good results; the vibrations were significantly reduced and the ROP increased compared to offset wells;
Example showing ROP and run distance effect from the AST
By reducing surface vibrations, the noise level was reduced to a level that is acceptable when drilling in a residential area and damage to surface equipment was eliminated. Furthermore, drilling time was reduced and the sections were drilled without tripping.