Drilling intake wells in carbonate formations to provide water for drilling purposes

The realization of drilling works oriented towards the prospection and extraction of hydrocarbons from conventional and unconventional resources requires the supply of large amounts of water for technological purposes and fracturing jobs in shale formations. One of the important sources of water supply for wellbores may be useful groundwater levels taken in by deep wells. Technological processes accompanying drilling works and other technological operations require large amounts of water in a short period of time. The possibility of drilling intake wells at the drilling site significantly reduces the costs of acquiring the necessary quantities of water and facilitates its transfer to technological installations. Such wells must have high yields. Accordingly, this necessitates drilling wells with a relatively large diameter to accommodate filters with a large active surface area, a considerably thick gravel pack, and a high‑capacity pumping unit. Drilling large diameter intake wells in difficult geological conditions using the rotary percussion method with simultaneous casing is much more efficient than the water‑based rotary mud or percussion methods used to date. This paper presents principles for selecting technological parameters of drilling large diameter wells in difficult geological conditions using the percussion‑rotary method with simultaneous casing. Among the main advantages of this method (as compared to the rotary method with drilling fluid) is its high RPM and the related lower cost of the well. Eliminating water‑based drilling mud has a positive effect on the hydraulic efficiency of the well and enhancement work can be omitted in many cases.