Utilizing a Paper-Based Platform for Oilfield Applications: Time-Resolved Fluorescence Imaging and Detection of Interwell Chemical Tracers.

Chemical tracers are indispensable tools for enhancing reservoir characterization and optimizing production processes in the oil and gas industry. Particularly, interwell water tracers provide key data for efficient water flood management and the improvement of production rates. However, the analysis of these water tracers within reservoir fluids is challenging, requiring laborious separation and extraction steps that often rely on complex instruments and skilled operators. Real-time analysis is especially problematic in remote areas with limited access to well-equipped laboratories. To address these challenges, we introduce a paper-based platform for the time-resolved fluorescence detection of dipicolinic acid (DPA) tracers complexed with terbium ion (Tb3+). Our innovation is driven by the need to simplify tracer analysis, make it portable, and enhance accessibility for oilfield applications. By leveraging the unique properties of cyclen-based macrocyclic ligands, we have achieved the stable and sensitive immobilization of Tb3+ on quartz microfilter paper, eliminating the need for extensive laboratory-based procedures. We achieve the stable and sensitive immobilization of Tb3+ on quartz microfilter paper by leveraging the unique properties of cyclen-based macrocyclic ligands. This innovation enables the formation of highly fluorescent, oil-blind, and optically detectable DPA-Tb3+ complexes at the paper surface. We visualize and capture these fluorescence signals using an intensified charge-coupled device camera via time gating, effectively suppressing undesirable fluorescence originating from crude oil. The quantification of DPA concentrations is achievable down to 158 ppb (9.45 × 10-7 M), as confirmed through time-resolved fluorescence microplate reader measurements. We also demonstrate the practicality of our technology by detecting DPA tracers in the presence of crude oil contamination, a common challenge encountered in oil production wells.

Laser-Induced Tar-Mediated Sintering of Metals and Refractory Carbides in Air.

Refractory metals and their carbides possess extraordinary chemical and temperature resilience and exceptional mechanical strength. Yet, they are notoriously difficult to employ in additive manufacturing, due to the high temperatures needed for processing. State of the art approaches to manufacture these materials generally require either a high-energy laser or electron beam as well as ventilation to protect the metal powder from combustion. Here, we present a versatile manufacturing process that utilizes tar as both a light absorber and antioxidant binder to sinter thin films of aluminum, copper, nickel, molybdenum, and tungsten powder using a low power (<2W) CO2 laser in air. Films of sintered Al/Cu/Ni metals have sheet resistances of ∼10-1 ohm/sq, while laser-sintered Mo/W-tar thin films form carbide phases. Several devices are demonstrated, including laser-sintered porous copper with a stable response to large strain (3.0) after 150 cycles, and a laserprocessed Mo/MoC(1-x) filament that reaches T ∼1000 °C in open air at 12 V. These results show that tar-mediated laser sintering represents a possible low energy, cost-effective route for engineering refractory materials and one that can easily be extended to additive manufacturing processes.