This paper describes the methods developed for testing and qualification of novel lightweight drilling fluids (foams, glass-bead fluids) using a unique pilot-scale test facility (PSTF). The performance criteria included fluid stability, rheology, pressure transmission, and gas migration under downhole conditions. Test results demonstrating the methods developed are provided, along with the capabilities of the facility, custom fixtures, and equipment that were built to study the performance of these fluids. A set of performance criteria and testing requirements were initially developed, which were then used to design and fabricate a novel pilot facility. The PSTF could generate downhole drilling conditions of 7,500 psig and temperatures above 300°F. Three custom-instrumented test articles were built to simulate wellbore geometry; one 10-ft long and one 18-ft long, both with a 2.62-in ID. The third article had a 10-ft long 6-in × 4-in annulus, with the eccentric internal pipe capable of 100-rpm rotation to mimic the drill string. The test articles could incline up to 45° to simulate deviated wells. Gas could be injected, and its migration rate measured in static and countercurrent flow using a video camera with full-bore sight glass, and gamma-ray densitometers. Dedicated sections for foam generation, measuring density, rheology, pressure transmission, and fluid sampling and imaging were provided. Upon commissioning of the PSTF, a 1 1/2 year test program was successfully carried out using lightweight foams and hollow glass-bead fluids. Due to the novel nature of the tests, best practices and procedures were developed through experimentation to quantify static and dynamic fluid stability, gas migration, foam generation techniques, fluid imaging and characterization, pressure transmission, and rheology. A variety of measurement techniques and instrumentation were trialed in the test articles to determine the best methods for tracking gas migration. Experiments in the test articles yielded a large amount of performance data, including fluid stability over time at different temperature and pressure conditions, the impact of drill string rotation on fluid stability, migration velocities of gas bubbles (i.e., gas kicks) within the drilling fluids at stagnant and countercurrent flow conditions, and the impact of drill string rotation. Pressure transmission speeds were measured in the foam with varying gas fractions. Example datasets from the testing program are provided, along with detailed descriptions of the test methods. The methods and test facility used to study lightweight drilling fluids are unique to the authors’ knowledge. For the first time, drilling fluids were analyzed in an annulus with a rotating pipe at downhole conditions at a pilot scale, and fluid stability along with gas migration were studied. These provide for rigorous testing of lightweight drilling fluids; the application of these fluids is expected to increase with declining reservoir pressures in oil and gas fields.

This project evaluated current end treatment designs that are used in the natural gas industry and used Computational Fluid Dynamics (CFD) to determine the end treatment with the best flow characteristics when installed upstream from an ultrasonic flow meter. The project team optimized the end treatment design and additional CFD and experimental testing was conducted. The experimental results of the developed end treatment were shown to provide results within �0.25% relative to the baseline configuration with various inlet conditions and numbers of ultrasonic paths.

This research effort focused on identifying equipment and processes that can be applied at compressor and pump stations to improve station operating efficiency, thereby reducing greenhouse gas (GHG) emissions. The project approach included a literature review and a PRCI member-company survey followed by evaluation and analysis and reporting tasks. This report has a corresponding webinar.

This project provided additional data analysis and data processing techniques to a data set that was collected under the previous MEAS-6-17A project. The goal of this project was to reduce the bias in the flow verification data and improve the repeatability of the results. The project was successful, as all of the methods developed on this project resulted in an average error better than �0.05% with a standard deviation of less than 1.1% for the longest injection length, which was a significant improvement from the previous MEAS-6-17A project.

Using foams to drill in low pore pressure reservoirs is attractive because of their low density, high viscosity, and ability to transport cuttings. However, in high temperature reservoirs (240 °F) with H2S gas present, there are concerns with the long-term stability of a foam drilling fluid. In this work, we highlight a lab program to develop a stable drilling foam for drilling in a low pore pressure, high temperature reservoir. The work also includes pilot-scale experiments to evaluate foam performance. Aqueous nitrogen-in-water foams were stabilized with a preferred foaming surfactant formulation, and the rheology and stability of the foams were measured at representative drilling conditions (temperature and pressure) at the lab and pilot-scale. The foams were also evaluated for their compatibility with current drilling fluids used on site and for stability in the presence of H2S gas (at 1900 psi and 140 °F). The drilling foam was also evaluated using a pilot-scale flow loop comprised of a rheology flow loop and a model drilling wellbore. The experiments included measuring the foam rheology, foam stability in the model wellbore, and gas migration tests to understand how the foam suppresses upwardly migrating gas bubbles. We successfully developed a surfactant stabilized foam designed for a high-temperature reservoir with H2S gas present. We found that H2S can negatively impact foam stability if proper surfactants are not selected. Our foam showed less than 10% liquid drainage after 12 hours at 240 °F and showed no significant degradation upon contact with 17 mol% H2S gas. Additionally, the foam was compatible with all drilling fluids (both water-based and oil-based) currently used at the drill site and demonstrated good stability in a model pilot-scale drilling wellbore. Interestingly, when the wellbore was angled at 30 degrees from vertical with the eccentric drill pipe rotating at 100 RPM, the foams were susceptible to degradation compared to an equivalent scenario of a vertical wellbore with concentric rotating drill pipe. The gas migration tests at the pilot-scale showed the foam was capable of significantly slowing down an upwardly moving gas bubble with and without pipe rotation.