This paper discusses the key factors of the dynamic-static drainage consolidation method as it applies to a petroleum storage site that features very soft mud of strength as low as 8.5 kPa. A field experiment was conducted to study the key factors on the success of this method such as effects of the number of tampings and the number of passes. The excess pore water pressures, settlements, field vane strengths were measured. Analysis of the results of measurements at the site leads to the conclusions that this method gives excellent results for strengthening the very soft mud. In addition, for a given total compaction energy, better result is obtained by increasing the number of passes with corresponding decrease in the number of tamping in each pass and limiting the compaction energy at a point for each pass to less than 1000kN.m.