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rwsn » Flagships » Cost-effective Boreholes » Key Principles » Drilling Equipment

Drilling Equipment

Smaller and less costly rigs should be utilized to provide boreholes that are fit for their designed purpose.

What do we know?

Rigs in use in Kenya have been oversized for the purposes of rural handpump boreholes (Doyen, 2003).  This is also the case in parts of Ethiopia (Carter et al, 2006).  In Mozambique, the only organisations using light rigs are NGOs while the private sector enterprises use large conventional rigs.  When a driller can only buy one rig, they will try and invest in the largest possible rig, at it gives them flexibility.  There is a tendency to overestimate required well depth and over-drill, which also has a bearing on the equipment that drillers decide to invest in (Carter et al, 2006).

Baumann et al (2005) state that most drilling operators in Tanzania use old equipment, with the result that breakdowns are frequent and the performance is slow.  Most of the drilling equipment in Senegal, Burkina Faso, Mali and Mauritania is old (some over 30 years) and lacks adequate maintenance (Antea, 2007).  68% of drilling rigs in Ethiopia are older than 15 years (Carter et al, 2006).  Maintaining ancient equipment is costly and time consuming.  The wide variety of rigs in use means that spares need to be sourced from all over the world.

High borehole standards are not the only cause for use of large and expensive drilling equipment.  Discussions with Government stakeholders and drillers in Niger (Danert, 2005) revealed a lack of awareness of new light conventional rigs on the international market.  In other countries, stakeholders may be aware that the equipment exists but unsure of the rig capability and wary of the claims made by equipment manufacturers.  Improved access to reliable information on drilling equipment is essential.  Hoping that this can be found on the Internet is insufficient.

Manual drilling is a viable alternative in particular environments (soft formation and shallow groundwater) and is currently taking place in Niger, Benin, Burkina Faso, Nigeria, Chad, Ethiopia, Mozambique, Malawi, Madagascar, South Africa, Senegal and Tanzania.  There have even been assertions that in some parts of Chad and Nigeria, conventional drillers win contracts and sub-contract the work to hand drillers.  Unfortunately, very little has been documented about the experiences of such drilling enterprises, the challenges that they face or how they could directly contribute towards cost-effective boreholes in sub-Saharan Africa. 

A preliminary analysis of the potential for hand drilled wells in terms of geology and hydrogeology estimates that 12% of the total population of sub-Saharan Africa (SSA), or 18% of the rural population of SSA, could be served with hand-drilled wells (Danert, 2007).  Savings of US$ 1 billion could be made as a result of tapping 50% of the estimated potential for hand-drilled wells in rural sub-Saharan Africa3.  This needs to offset against the cost of the required studies, training and support to realise this as well as protecting the sources from contamination.

See RWSN's field note Solutions for Reducing Borehole Costs in Rural Africa for some good insights regarding the benefits of utilising smaller drilling rigs.

References