Design Perspectives for Selection of Subsea Gas Lift Technology for Deep Water Fields

Riser base gas lift is conventionally used in deep water fields to minimize backpressure on wells, smooth start-up transients, and mitigate slugging in the flowline-riser system which can cause disruption in the topside facilities. The effectiveness of riser base gas lift depends on several factors, such as the reservoir performance, the fluid properties, the field architecture, and the topography. There are several technical solutions available to deliver the lift gas to the riser base. Such technical solutions differ in terms of lift-gas supply method (distributed vs point-to-point), riser specifications, and overall system complexity. The selection of technical solution has the potential for minimizing infrastructure. Available solutions include bundled risers and concentric riser configurations that allow gas lift functions to be integrated with the main production conduit. The evaluation of riser base gas lift effectiveness and the selection of the most appropriate technical solution is typically performed early in the field development cycle. This paper presents a review of the available subsea gas lift technical solutions and discusses an evaluation process, including criteria for the selection of the most appropriate solution. The presented case study assumes a deep water Gulf of Mexico field, in which the main subsea system consists of two wet insulated piggable flowline loops. Key decision drivers were flow assurance requirements, complexity, operability, impact on field layout, interfaces, installation, and schedule are discussed. This holistic approach aids the selection of the most appropriate riser base gas lift system in the early field development cycle.

The malfunction of a double-base propellant gas generator

The paper presents results of research aimed at determining the cause leading to the malfunction of a double base gas generator. For the purposes of this work, gas generator charges and combustion chambers were intentionally damaged in order to replicate failure conditions. Damage to the inhibitor covering the gas generator and contamination in the combustion chamber, was simulated. The damaged charges and chambers were subjected to ballistic tests.

Numerical Analysis of Two-Phase Flow in Fluidized Bed Reactor With Jet Nozzle for Polysilicon Growth

The present study has been conducted on three dimensional flow characteristics between poly-silicon particles and gas in a large scale fluidization bed reactor (FBR). This study was mainly performed numerically by commercial code Fluent. The Eulerian multiphase model was used to simulate hydrodynamics of bubbling fluidized bed. The size of silicon particle was 1000 μm and 2000 μm, and density was 2329 kg/m3. The reactor chamber had base gas flow from bottom porous plate and reacting flow from the jet nozzles (single or multi) with high velocity. The base gas and reacting gas were hydrogen (H2) and trichloro-silane (TCS) respectively. The TCS mole fraction was controlled to 13% and 20% of total gas amount. From the simulation, performance and design parameters were evaluated on single and multi nozzles jet related to flow mixing characteristics and a gas-solid contact performance. As a result, considering of the mixing characteristics between the gas and the solid, multi nozzle jets much improved the mixing performance in the reacting zone. In addition, the widespread distribution of TCS which led to better gas-solid contact performance were showed by the multi nozzle jets. This CFD data will provide useful basis to predict fluidization characteristics in the poly-silicon FBR process.