1. n. [Drilling]

In onshore operations, an earthen-bermed storage area for discarded drilling fluid. These small reservoirs are used for several reasons. First, when properly arranged, most of the solids in the mud settle out and a suction hose may be placed in the reserve pit to have additional fluid available to pump into the wellbore in an emergency. In addition, in arid areas, a considerable amount of evaporation occurs, thus minimizing mud disposal volumes. At the end of drilling operations, and perhaps at intermediate times during drilling, the fluids and solids in the reserve pit must be carefully discarded, usually by transfer to a properly certified landfill. If the mud is benign, the solids (mostly clay), and liquids (water), may be plowed and tilled back into the local soil. This technique of disposal and reclamation is known as land farming.