Device for fusion drilling with simultaneous or follow-up reaming of wells in ice

The paper deals with a new opening technology for subglacial reservoirs, which ensures environmentally friendly geological exploration. The technology is based on the results of the first openings of the subglacial Lake Vostok in Antarctica (February 2012 and January 2015). The primary goal of further studies of the subglacial Lake Vostok is to take clean samples of lake water and bottom sediments, which requires direct penetration into the lake. There is a number of conditions to be met in order to conduct further studies of the lake using a clean access well at the Vostok drilling complex. The article summarizes the main results including technological and engineering solutions protected by the patent of the Russian Federation. A detailed consideration is given to a new device for fusion drilling with simultaneous reaming of an ice hole. This device combines two technological processes: drilling due to contact melting, and an increase in the diameter of the well due to the creation of a vortex flow of a continuously heated coolant in the bottomhole zone. The thermal method of ice breaking ensures the ecological cleanliness when opening subglacial reservoirs and is a priority method that favorably differs from the existing ones. The device was named a “thermal drill reamer” (TDR). During the seasonal work of the 64th Russian Antarctic Expedition bench tests of the TDR 132/400 were carried out, the results of which confirmed that the device is capable to ensure 132 mm drilling with simultaneous reaming up to 400 mm.