Reaming While Drilling

Reaming while drilling is an advanced drilling technology that involves the use of specialized tools to enlarge the diameter of the borehole while simultaneously drilling. This technique utilizes reaming while drilling tools in conjunction with conventional drill bits to achieve a larger borehole diameter than that of the upper casing string. Reaming while drilling offers several advantages, including reducing the need for additional trips to the wellbore, improving efficiency, and finding widespread application in challenging drilling scenarios such as deep wells, ultra-deep wells, small gap wells, side drilling, and complex well conditions. This technology has significantly evolved due to the introduction of reaming while drilling tools.

Reaming while drilling tools have distinct advantages over traditional fixed-blade reaming tools. These tools have contributed to the rapid advancement of reaming while drilling technology. There are two primary operating modes associated with reaming while drilling:

· Mode 1: In this mode, the drilling mud flows through the drill bit's center flow channel when the steel ball is not being thrown. During this phase, the reaming cutters remain closed, resulting in no reaming effect on the borehole.

· Mode 2: When the steel ball is thrown and positioned at the ball seat, the system shifts into mode 2. The applied pressure cuts the pin, causing the ball seat to move downward. This action opens the bypass flow channel of the reamer, allowing the reamer to divert drilling mud and initiate the reaming process. In this state, the reaming cutter's blades extend to effectively enlarge the borehole diameter while drilling.

In summary, reaming while drilling is an innovative drilling technique that utilizes specialized tools to enlarge the borehole diameter during the drilling process. This technology has proven to be highly effective in various challenging drilling scenarios and has been made possible by the development of reaming while drilling tools. The operating modes of these tools, involving the use of steel balls and reamer blades, contribute to the successful execution of the reaming while drilling process.