Résumé des résultats (Abstract)
(Anglais)
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Problem to be solved
The larger hydrocarbon reservoirs in Europe are rapidly depleting. The remaining marginal fields can only be exploited commercially by the implementation of new 'intelligent' technology, such as electric Coiled Tubing drilling or Intelligent Well Completions.
Steel CT with an internal electric wireline is the current standard for such operations. Steel CT suffers from corrosion and fatigue problems, which dramatically restrict the operational life. The horizontal reach of steel CT is limited due to its heavy weight. The inserted wireline results in major hydraulic power losses and is cumbersome to install.
Objectives
This project aims to solve these problems by researching and developing a high-temperature, corrosion and fatigue resistant thermoplastic Power & Data Transmission Composite Coiled Tubing (PDT-COIL) for electric drilling applications. This PDT-COIL contains embedded electrical power and data conductors and a fibre-optic sensing and monitoring system. Compared to conventional rotary drilling, such a PDT-COIL will result in 45% less required workspace, 50% reduction of rig height, 60% noise reduction, 70% less rock cuttings and a power exhaust generation reduction of 85%. The PDT-COIL will result in 35% overall cost savings on the exploration of hydrocarbons. Time to first oil will be reduced due to the support of enhanced logging while drilling capabilities.
Outline of the work
The project consists of two main phases. In phase A, Research was conducted on all components of the Intelligent PDT Coil. In phase B, these components will be combined into a test model. This scale model will be mounted at the end of a steel coiled tubing and field tested. The objectives of this test are to prove the feasibility of electric drilling with a PDT-COIL and the continuous monitoring of both the drilling process and the structural integrity of a coil.
Upon completion of phase A, the project was evaluated. Since the results of phase A were encouraging, a renewed project proposal was submitted and accepted by the European Commission for the funding of phase B.
Components of the PDT-COIL
The structural composite layers of the CCT form the main component, these have to carry all the mechanical, thermal and chemical loads. They consist of both carbon and glass fibres embedded in high performance thermoplastic polymers. The electric conductors (which are embedded in the wall thickness) provide electric power for Electric Submersible Pumps or Electric Drilling Motors and can also be used for data transmission. They consist of insulated copper wires.
A fibre-optic Sensing and Monitoring System is be embedded in the wall along the entire string length. This system measures on-line relevant parameters, monitors the structural integrity of the PDT-COIL and can be used for data transmission. The composite material is virtually insensitive to fatigue, so the limiting factor for the service life will be the wear characteristics of the coating and chemical ageing of the polymer matrix material. Of these the chemical ageing is most important because a coating can be reapplied to the coil if necessary. Therefore monitoring of the chemical ageing of the coil is an important factor for efficient application.
For the operation of the PDT-COIL, a new control system is be necessary. Existing CT software will be modified to account for the behaviour of the composite material and the electrical equipment. The sensing and monitoring system will be integrated in the control system. Existing surface equipment needs to be modified for optimal performance of the PDT-COIL. These modifications will be designed and tested.
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