SITE INVESTIGATION

Deep recharge and monitoring wells in Doha

The use of monitoring technology supplied by Robertson Geo in the geophysical logging of boreholes at a site in Doha, State of Qatar.

 Preparing the equipment for borehole logging in Doha

Preparing the equipment for borehole logging in Doha

Technology supplied by Robertson Geo was used on a project in Doha, State of Qatar, where Gulf laboratories Co., was carrying out drilling, geophysical logging and pumping tests.

The project saw a geotechnical borehole drilled to 160m, a 400m deep injection well, a deep monitoring wells at 400m and a shallow monitoring well drilled to 50m.

Calliper, resistivity, fluid conductivity, HiRAT and sidewall density tests were performed in the geotechnical borehole while calliper, resistivity and fluid conductivity were performed in the deep injection well.

Again, calliper and resistivity logging was performed in both the deep and shallow monitoring wells as well.

For the thorough assessment of area HiRAT, calliper and fluid conductivity logging were done in the geotechnical borehole.

For the estimation of porosity, density logging was also performed in the geotechnical borehole and porosity was calculated by using the formula: http://www-odp.tamu.edu/publications/chars/emptyset.gif= (http://www-odp.tamu.edu/publications/chars/rho.gifm-http://www-odp.tamu.edu/publications/chars/rho.gifb)/(http://www-odp.tamu.edu/publications/chars/rho.gifm-http://www-odp.tamu.edu/publications/chars/rho.giff). Where the edited bulk-density (http://www-odp.tamu.edu/publications/chars/rho.gifb) log measurements were then used to calculate sediment porosities http://www-odp.tamu.edu/publications/chars/emptyset.gif in water densities (http://www-odp.tamu.edu/publications/chars/rho.giff) were assumed to be constant and equal to 1.05g/cm3 for each hole. However, variable core-derived grain/matrix densities (http://www-odp.tamu.edu/publications/chars/rho.gifm) were assumed for each calculation. The core-derived grain densities (http://www-odp.tamu.edu/publications/chars/rho.gifm).

HiRAT provided precise information about the lithology which was well supported by the natural gamma-ray log.

The fluid conductivity log was well correlated to the location of a more porous zone where mixing of comparatively more conductive water was taking place through the porous and permeable zone.