Drilling large diameter water wells in carbonate strata in the Lublin area

Abstract

One of the most important sources of water for communal purposes in the Lublin area are the useful groundwater aquifers intaken with deep drilled wells. Such wells should be highly efficient and localized in a close vicinity of the local water supply network to lower the cost of transport. Large amounts of water can be produced by large diameter wells, where heavy duty pump aggregates can be installed. High rates of penetration cannot be obtained if the profile abounds in hardly drillable carbonate. This elongates the time of drilling and increases negative impact of mud on the near well zone of the aquifer. It also lowers hydraulic parameters of the well. To improve the efficiency of the wells, drillability tests with cogged bits were performed in carbonate rocks to optimize the mechanical parameters of drilling. Measurement sections, each 0.3 to 0.5 m long, were selected for the tests. Each section was drilled at constant rotational speed and weight of bit values. Prior to the drillability tests, the limits on the weight of bit and rotational speed of the bit were established, in line with the technological characteristic of rig Wirth B3A, strength of the string and of the cogged bit.