Exel Composites' Diversified Structural Composites (DSC) developed fiber-optic embedded carbon composite rods for the innovative well intervention system of the Norwegian company Ziebel. DSC's expertise in carbon fiber pultrusion enables precision fabrication of 15 mm diameter bars with a fiber core as a sensor that collects real-time insights into well performance not possible with conventional methods.
Enhanced recovery factor
Founded in 2006, Ziebel aims to be a factor in enhanced oil recovery through innovative technologies and solutions. In order to make informed decisions, the oil drilling and completion team needs detailed information on the fluid flow in and around the borehole during production or injection. This data is typically collected using production logging tools, but this approach is operationally challenging and provides limited, time and location specific information. Ziebel's proprietary technology, based on the Distributed Optical Fiber (DFO) Z system, does not have many limitations that limit traditional logging efficiencies, providing a better understanding of well and reservoir behavior.
At the heart of the Ziebel Z-System is a 6.2-kilometer, 15-mm diameter carbon fiber rod (Z-bar) made by DSC that securely mounts multiple cables in a harsh downhole environment. Typically, the rod is deployed into a production or injection well for 48 hours, where the fiber optic sensor measures temperature and acoustic vibration along its length. This enables a variety of applications - including flow distribution, fluid motion visualization, leak detection and stimulation fluid monitoring - for critical well and reservoir management.
This composite-based sensing system has more advantages. Carbon rods enable horizontal well passages because lightweight, rigid composite rods can “push” from the surface to the horizontal sections that are often used in today's wells, which is impossible with conventional tools running on cables unless electric well tractors It is adopted. In addition, small-diameter carbon rods can enter wells with limited inner diameters and difficult geometry, other tools do not pass, have minimal suffocation effects on wells, and unlike metals, they are inert to most harmful and corrosive materials. In a downhole environment.
Powerful manufacturing process
In 2006, Ziebel contacted the US carbon fiber pultrusion specialist DSC to develop and manufacture robust composite rods for fiber optic intervention technology in the petroleum sector. To ensure the necessary combination of strength, stiffness and corrosion resistance required for this application, DSC chose a proprietary tough epoxy resin and specific carbon fibers selected through extensive testing to maximize mechanical properties. This resin poses a particularly challenging requirement for the pultrusion process because it requires very slow curing to achieve its optimum performance. This means that in order to produce each 6.2 km long rod, the pultrusion line must be continuously operated without failure for more than 3 weeks.
“The high process cost of carbon fiber and fiber is very high,” explains David Lewis, Director of Technology and Business Development at DSC. “As a result, we have done a lot of work and developed an extremely robust and foolproof pultrusion process with superior process control measures to ensure no failure.”
Ziebel and DSC worked together to optimize the winding technology to handle and transport long length pultrusion rods. This allows rigid carbon fiber rods to be wound onto reels of sufficiently small diameter for transport from the DSC production facility in Erlanger, Kentucky, to Europe and the Middle East and the United States. The NDT process is used to monitor the quality of the bar because the product is continuous and cannot be cut and inspected.
future development
Ziebel is committed to expanding its portfolio through innovations in its current Z-Rod products and other products that leverage its cutting-edge fiber optic sensing and data analysis capabilities.
“We have a lot of trust and confidence in DSC partners, which will enable us to continue to push the boundaries of carbon composites in the harsh downhole environment of oil and gas wells. Our next-generation Z-Rod will bring us operating temperatures 350 degrees Fahrenheit (177 degrees Celsius) opens up additional wells for our service," said Neil Gardner, vice president of technology at Ziebel.
Ziebel and DSC have signed an exclusive agreement to develop and manufacture advanced fiber/composite downhole sensor rods.
The Finnish-based pultrusion group Exel Composites acquired the DSC in May 2018, marking its entry into the US market.
“We congratulate Ziebel on the successful introduction of its innovative oil well intervention system and we look forward to working with them to further expand their applications,” said Kari Loukola, Senior Vice President and DSC President of Exx Composites America. “The project clearly demonstrates the carbon pultrusion capabilities that DSC brings to the Exel Group, as well as our comprehensive expansion, and we expect significant opportunities in the oil and gas industry as well as other major markets such as wind and aerospace.”
