Hybrid Conductor-Supported Tripod Platform: Brownfield Design Perspective to Unlock Production Capacity

Objectives/Scope Oil and gas companies have shifted their investment priorities to low CAPEX brownfield projects in response to historically low oil and gas prices. One approach is to increase the production by drilling new wells and tying them back to existing tripods. However, existing tripods have limited as-built design data and are usually near the allowable structural capacity limits. This study introduces a novel concept of the "hybrid conductor-supported tripod" to support the new wellheads. This approach minimizes the need to modify the existing tripods. Methods, Procedures, Process The hybrid conductor-supported tripod utilizes the new well conductors to support the wellheads, extends to the existing tripod topside to support the production facilities, and resists lateral loads from the new wellheads. Such hybrid conductor-supported tripod takes advantage of the axial compression capacities of the new conductors while its lateral resistance is provided by integrating only the new topside with the existing tripod's topside. Thus, the underwater structural modifications of the existing tripods are minimized. Results, Observations, Conclusions Design and construction challenges commonly encountered during the design phases of brownfield projects include: 1) lack of tripod jacket and foundation as-built data, 2) need for bracing the new conductors to the existing jacket underwater due to buckling and vortex issues, 3) as-built conditions of the tripods are already near their structural capacities. The design and construction issues experienced in low budget and tight schedule brownfield projects are alleviated with the use of a hybrid conductor-supported tripod. A parametric study was conducted to identify the minimum conductor pipe diameters needed for hybrid conductor-supported tripods at various shallow water depths in benign environmental conditions. The in-place conditions of several existing tripods were investigated before and after the hybrid conductor-supported tripods were integrated with the existing tripods. Using hybrid conductor-supported tripods enable production increase on existing facilities with minimal CAPEX investment. This is accomplished by: 1) utilizing existing tripods to increase production, 2) mitigating the need for as-built data, especially underwater jacket data, 3) eliminating additional axial loads on the existing tripods, 4) implementing minimum deck extensions on the existing tripods. Novel/Additive Information The hybrid conductor-supported tripods provide the structural expansion need for the new wellhead facilities while keeping the existing tripods in their as-built conditions. Reducing the need for the current condition and the exact as-built underwater information of the existing tripods will accelerate the execution of the low budget and tight schedule production increase brownfield projects.

Novel Hybrid Conductor of Irregularly Patterned Graphene Mesh and Silver Nanowire Networks

We prepared the hybrid conductor of the Ag nanowire (NW) network and irregularly patterned graphene (GP) mesh with enhanced optical transmittance (~98.5%) and mechano-electric stability (ΔR/Ro: ~42.4% at 200,000 (200k) cycles) under 6.7% strain. Irregularly patterned GP meshes were prepared with a bottom-side etching method using chemical etchant (HNO3). The GP mesh pattern was judiciously and easily tuned by the regulation of treatment time (0–180 min) and concentration (0–20 M) of chemical etchants. As-formed hybrid conductor of Ag NW and GP mesh exhibit enhanced/controllable electrical-optical properties and mechano-electric stabilities; hybrid conductor exhibits enhanced optical transmittance (TT = 98.5%) and improved conductivity (ΔRs: 22%) compared with that of a conventional hybrid conductor at similar TT. It is also noteworthy that our hybrid conductor shows far superior mechano-electric stability (ΔR/Ro: ~42.4% at 200k cycles; TT: ~98.5%) to that of controls (Ag NW (ΔR/Ro: ~293% at 200k cycles), Ag NW-pristine GP hybrid (ΔR/Ro: ~121% at 200k cycles)) ascribed to our unique hybrid structure.

Lightning Protection Methods for Wind Turbine Blades: An Alternative Approach

Lightning strikes happens in a fraction of time, where they can transfer huge amounts of charge and high currents in a single strike. The chances for a structure to be struck by lightning increases as the height increases; thus, tall structures are more prone to lightning. Despite the existing lightning protection systems available for wind turbine blades, there are still many cases reported due to the fact of damage caused by lightning strike. Owing to that, the present work introduces a new approach for a lightning protection system for wind turbine blades where preliminary investigations were done using Analysis Systems (ANSYS) Workbench. Two models were developed: one with a conventional type down conductor system and the other with a hybrid conductor system. The recorded findings have been compared and discussed, where it was found that the hybrid conductor system may provide alternative protection from lightning for wind turbine blades.

Systematic Investigation of the Electrochemical Properties of Natural Melanin for Various Electrode Cells

Melanin is an organic semiconductor from a broad class of functional macromolecules found in nature. It has hybrid properties of an amorphous semiconductor. However, natural melanin has not been widely studied; this is partially due to the lack of processing methods, as melanin is generally extracted and measured as a powder. Thus, better electrical methods are required; one possible solution is the use of electrochemical synthesis. We investigated the electrochemical properties of melanin at different degrees of acidity and for various electrode cells. The electrochemical properties of natural melanin were studied using two different techniques: the constant potential method and cyclic voltammetry. This could allow different types of charge transport and make melanin a contender in this rapidly growing field. Natural melanin is believed to be a hybrid conductor where the dominant charge carriers change between electrons and protons as the acidity degree and water concentration change. Biocompatible and biodegradable features make melanin useful for electrochemical energy storage and it could be an attractive candidate for applications in bioelectronics and electronics devices.