16th June 2021
Common applications include removal of fracturing plugs and proppants, hard scales, well-bore isolations plugs, compact debris, fish and many more. Whilst CT Milling applications are wide and varied all will include the use of a downhole motor and cutting device known as a Mill or a Burning Shoe.
The exact configuration and design of that Mill or Burning Shoe is entirely dependent on the application and should be designed in accordance with the objectives of the job. Taking into consideration the materials present in the well-bore and it’s geometry, the motor specifications along with the CT equipment capabilities.
Under-Reamers provide a solution to complete debris removal in large diameter bores where a smaller ID restriction exists above. Typically by increasing flow rate, cutting blades expand from the body of the tool which effectively creates a larger diameter mill than could be deployed through that ID restriction. Under-Reamers are extremely effective where there’s a need to remove scales and cement from the production tubular walls in order to minimise flow restrictions and maximise production.
Whilst Motor Selection and operational procedures are critical, the success of milling operation often depends on the design of the mill. As well as offering a large number of standard mill designs LiMAR also offer a Mill and Burning Shoe design service where products are built specifically for the application in hand.
LiMAR’s CT Motor range offers customers the flexibility to choose from a number of different power section designs to couple with one of the most effective oil lubricated lower ends on the market. The use of a titanium flex shaft, an extremely low friction bearing pack with overload protection and a Rotor Catch make this a winning combination.
LiMAR’s Under-Reamer and High Expansion Under-Reamers offer a solution to every possible scenario. The Under-Reamer provides a moderate level of expansion in applications where ID restrictions aren’t so severe. The three milling blades are supplied dressed with a combination of specially designed carbide inserts and crushed Carbide to provide a hard wearing cutting structure which resists the tendency to chip through vibration. The High Expansion Under-Reamer provides a solution where there’s a need to pass an extremely restrictive ID or Tubing String above and open up to almost three times the nominal tool diameter. As with the lower expansion tool the upper and lower sets of blades are offered with chip resistant Tungsten carbide inserts which are designed specifically for the job in hand.
The Flo Activated Circ Sub and Set Down Circulating Valve offer means of improving hole cleaning and ensuring all debris is removed from the well-bore. Often flow rates are restricted by the motor which can lead to solids beds forming and the need to increase annular velocity, or conduct a wiper trip in order to achieve complete debris removal. These two products offer completely different approaches to achieving this goal.
If you'd like more information on any of our CT tools, contact our specialist team today