TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper will describe how the operator planned and drilled an eight-well sidetrack program, including one horizontal application, in Main Pass 299/144 field, Gulf of Mexico (GOM), in record time. This achievement was accomplished by improving operational efficiency (incident free) and reaching bottom hole objectives quickly, thus reducing openhole exposure and costly "flat" time. The authors will discuss changes in the BHA, including mud motors, AKO settings, steerable ream while drilling tools and roller cone bits in addition to synthetic mud systems, that allowed each sidetrack operation to successfully drill oversize (eccentric technology) hole and hit the directional targets in record time.The authors will discuss why different technologies were chosen and outline successful operations. A case study will be where a 7-5/8" steerable ream while drilling system with a 4-3/4" steel tooth pilot bit was able to build from 0° to 90° in one run, a record for the area.Finally, the authors will document, with historical offset data, how improving operational efficiency and new bit technology reduced costs by approximately US$7.3 million on the eightwell program. Analysis will include a mechanical risk index that takes into account a variety of well variables to objectively compare costs on wells drilled in GOM.