2nd June 2021
Removing debris from a well-bore, or “cleaning out” is the most prevalent Coiled Tubing application in Well Intervention. The process requires the creation of a high pressure jet impact used to break down debris and entrain it within the fluid stream, which must also have sufficient carrying capacity to lift the entrained debris up the well-bore to surface.
Depending on the characteristics of the well-bore, the type of debris and the available CT surface and pumping equipment there are numerous approaches which are adopted. Tooling selection will vary from very basic BHA designs with no moving parts, to much more complex approaches where the procedures are broken into stages and the BHA design becomes much more involved.
A clean out in its simplest form would be a relatively shallow and vertical hole with smaller ID tubulars where produced fines have settled in the wellbore. In such a scenario there would be little need to spend excessive effort analysing jet impact pressure, annular velocity or BHA design in order to achieve a successful clean out. The jetting tool selection for such an application could be as simple 4 or 5 Ported Jetting Nozzle, or Perhaps a Multi-Jet Tool to offer some further flexibility in jet pattern and orifice selection.
In situations where the debris is known to be compact, or scales, paraffins or waxes have built up on the tubulars there could be a need to create a significant impact force to remove the debris from situ. This involves creating a greater pressure drop across the jetting orifice and careful consideration is given to the ID of those orifices. These types of operations would typically limit the available pump rate and hence the annular velocity needed in order to remove debris from the well-bore. Far more consideration to fluids, job procedures and BHA selection will be required in order to achieve success.
LiMAR offer a wide variety of Jetting and Clean Out Tools to cover all scenario’s. From the most basic of Jetting Nozzles to range of Abrasive Jetting Tools, which not only enable clean outs to be conducted with the use of an abrasive medium, but can be used perforate tubulars and formations.
The unique Abrasive Jetting Bypass Tool was designed to allow a number of applications to be performed in a single run, the ball operated tool reverts from flowing through the BHA below, to Annular Abrasive Jetting and reverts flowing to the BHA below, thus reducing the number of runs required to achieve the planned objectives.
In situations where annular velocity is limited the Flo Activated Circ Sub allows the jet stream to switch multiple times from a high impact, high pressure jetting mode to a rearward facing, low pressure cleaning mode. The 45 degree upward jets in Cleaning mode allow increased flow and annular velocity to aid in removing debris from the well-bore.
The popular Rotary Jetting Tool has undergone a number of enhancements to further improve it’s durability and reliability. Additional Rotary Seals have been included, along with an improved seat design and internal leak path to mitigate pressure build up on the Rotary Seals.
LiMAR’s Venturi Junk Basket has proven to be extremely efficient enabling sizeable solids to be lifted at extremely low flow rates. This product not only improves the likelihood of success in a standard CT operation but opens up an opportunity to Capillary CT Clean outs where pump rates can be as low as 5gpm.
No matter what your well demands, we are confident we can assist you in finding the right solution for your operational needs.