Hand sludging: a report from North West Bengal

Abstract

The Low Cost Drilling Project is developing a modification of the traditional Asian sludging technology for use in Africa. As part of the technology research a visit was made to north India to observe and measure various characteristics of this well drilling technique. The report describes these observations and draws conclusions for the Low Cost Well Drilling Project. The method and equipment used by the Indian drillers (\'mistries\') are set out, followed by an outline of the ergonomics and quantification of the work rates needed for hole cleaning and drilling. Drilling penetration rates in soft alluvium were observed to range from 16.5 to 45m per hour. Traditional and more modern designs of casing and wellscreen, and the corresponding well completion methods, are described. The cost of a 12 m water well drilled by sludging in North West Bengal is estimated at Rs200 (approximately £3-4). Practical conclusions are drawn in relation to equipment design for Uganda or elsewhere in sub-Saharan Africa