Improving well casing technology by drilling with expandable casing string

This article discusses new (innovative) well completion technologies that reduce economic costs and construction time, including casing drilling, expandable casing and monodiameter technology. The advantages and disadvantages of these technologies are considered. Casing drilling is one of the most advanced well construction methods, which prevents complications in the wellbore, due to simultaneous drilling and casing of the wellbore with casing pipes directly in the process of work. Due to the dimensions of the casing, there is constant contact with the well wall, which leads to mechanical clogging. When drilling deep, ultra-deep wells and wells with a large quantity of waste, there is a need for a large number of casing strings of different diameters, and there is not always enough varieties of pipe to provide them. One of the technological solutions for maintaining the diameter of casing strings when designing a well is the use of expandable casing pipes. Of all the advantages of using expandable tubular products, only one of them has the greatest potential – a well with a single bore diameter (Monodiameter). Monodiameter technology reduces the telescopic effect inherent in traditional designs. The possibility of combining two technologies into one, namely drilling with expandable casing pipes will lead to obtaining a well of one bore diameter (monodiameter). It is shown that the use of an expandable casing instead of a drill string is subject to greater risks than drilling with an expandable liner. Based on this, expandable liner drilling is the best option for using expandable casing.