Abstract A horizontal drilling program was initiated in the Panna field off the west coast of India during mid 1997 to tap the 20 m thick oil column in the Bassein limestone reservoir. There were formidable challenges – planning trajectories, choosing drilling fluids, steering, preventing the fragile time-dependent shale sections from sloughing in the high angle holes, formation evaluation, completion and the presence of up to 500 ppm H2S. The goal was to execute an accelerated development drilling program by drilling low cost, high quality wells from preinstalled platforms. Earlier directional and limited horizontal drilling experience in the field during the late eighties and early nineties had encountered significant drilling problems. By careful review of data and past practices, and aided by state of art equipment and services, the present drilling campaign has achieved significant improvement in drilling efficiencies and performance.