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BIA-Brukerstyrt innovasjonsarena

Low cost drill bit body material for geothermal applications.

Alternative title: Lav-kost materialer for borkroner til boring av geotermiske brønner.

Awarded: NOK 5.1 mill.

Project Number:

282128

Project Period:

2018 - 2021

Funding received from:

Location:

The underlying idea of the project is to reduce the cost of PDC drill bits, currently used extensively in the oil and gas industry, to a cost - level that makes them competitive in geothermal applications and thereby opening new markets for Lyng Drilling. This will be achieved by developing new and lower cost materials that will enable new manufacturing methods. Two main methods will be studied: 1) Develop low cost silicon carbide (SiC) powder particles with thin tungsten carbide (WC) coating (WC@SiC, core shell structures) for melt infiltration processing and potentially 3D printing. 2) Develop methods using reaction sintering for direct (single-step) fabrication of new, tungsten free, ceramic-metal composite (cermet) drill bits. Silicon carbide (SiC) coated with tungsten carbide (WC) provides a cheap alternative raw material for production of drill bit body. The tungsten carbide shell is essential to ensure wettability with metal binder alloy during the drill bit production. A modified Pechini method is utilized to coat WC on SiC using W precursors. A range of tests have been completed to optimize the process for industrial use. Industrial sources of tungsten precursors have been included in the test-plan and significant work has been done to successfully reduce the liquid volume of the initial chemical solution used in the coating process. The major issue worked on in the final phase of the project is the presence of concentrated volumes of carbon after the coating process that forms weak (voids in parts) areas in the infiltrated parts resulting in lower than required mechanical properties when scaling the process up to larger parts. This problem has been solved and good infiltration results are achieved. Mechanical testing and investigation of fracture surfaces have revealed that the matrix material does not meet the requirements for use in drill bit bodies. This is due to the mechanical properties of the individual SiC-particles (quality of SiC powder) used. However, the key challenge in qualifying alternative low-cost ceramics for use in drill bit bodies is related to the infiltration process. The LoCo2 project has been successful in achieving good infiltration quality using SiC through the process / method developed. The process is not limited to use on SiC (or a specific SiC quality). The results achieved in the LoCo2-project be used to investigate alternative low-cost ceramic alternatives, both in the SiC category and other alternative ceramics. Following the preliminary experiments on reaction sintering with the model system (standard thermite reaction Fe2O3-Al), the focus was changed to the titanium carbide system. Ti+C = TiC is the exothermic sintering promoting sintering, while binding metal like nickel can be added to the reaction mixture to suppress the reactivity and heat generation and at the same time binding the TiC reactant particles together in a strong cermet. The reaction sintering has been performed in within closed system and an electrical fuse for initiating the reaction. Cermet bodies with areas of ideal microstructure was formed, however, significant porosity remained in the structure on macroscale. Attempts to eliminate this porosity by adjustment of nickel-content or infiltration of the porous sintered bodies in a subsequent step did not result in large improvements. A design for a new set-up allowing for compression and removal of gas during the reaction sintering was made, however, the transfer to full scale drill bit system considered too challenging.

The main objective of the project is to develop a basis for producing high performance, low cost, drill bit bodies based on a metallic/ceramic composite. The drill bit body material is one of the main cost drivers of a PDC drill bit. Two alternative approaches are being investigated; reaction sintering of the body and infiltration of surface coated ceramic particles with a binder alloy. If successful, the present project is expected to put Lyng Drilling on the map in the geothermal drill bit segment. By utilizing the long experience of LD and their parent company Schlumberger Ltd., and the material competence and expertise at SINTEF on net shape ceramics processing, testing and analysis the project will hopefully result in new drill bit materials and new manufacturing processes. The preferred materials / processes will be used to make full scale prototype drill bits for drilling tests.

Activity:

BIA-Brukerstyrt innovasjonsarena