RIASSUNTO
Abstract
The main objective of the paper is to present the possibility of non-contact approach based on electrical plasma in downhole milling or cutting operations. The features of this approach can be beneficial for a variety of Well Intervention applications characteristic for Middle East region. These applications include slot recovery, side-tracking, pipe recovery and several others.
The presented approach utilizes thermal electrical plasma capable to disintegrate a variety of materials (steel, cement, rock) with the same tool. Milling or cutting using this approach is based on a hybridized plasmachemical and thermochemical processes resulting fast metal degradation and removal in water steam environment. The main processes responsible for the rate and effectivity of steel/cement removal are oxidative processes as well as melting and evaporation. This non-contact approach utilizing coiled tubing (CT) technology brings also improved reliability by minimization of wear and tear of the tool itself.
Based on its features, the technology can bring the following benefits into Slot recovery application area:
Multicasing milling in fewer trips
100% rigless operation – Light Well Intervention Vessel offering flexible use and satisfying immediate needs
Generation of small swarf (no mechanical stuck, less viscous and cheaper fluids)
Reduction of HSE-related risks due to reduced tripping and automated CT system
Reduction of issues with fluid management due to simplified handling with milled material
Shortening of the whole process due to its structural simplification
Similarly, the mentioned features can be used also for other potential applications including:
Multi-lateral side-tracking
Pipe recovery of stuck BHA
Repair/replacement of damaged casing
Wellhead retrieval
Moreover, after development and modifications of the tool geometry, it can provide an efficient substitution of conventional junk/fish milling tools.