The gas drift velocity in an elongated bubble can be measured as the bubble velocity moving through stagnant liquid in a pipe. In this study, Computational Fluid Dynamics (CFD) is used to numerically simulate the motion of elongated gas bubbles into liquidfilled channels and pipes. The steady, inviscid flow CFD solution agrees with the analytical solution. Furthermore, the CFD solution for viscous flow agrees with new experimental data. Two flow regimes were predicted by the viscous flow simulations: one of constant bubble velocity and another with decreasing bubble velocity over time. A change in flow regime is observed both in terms of the bubble shape and the gas drift velocity. Correlations are derived from the CFD results that describe the time dependent drift velocity as a function of the liquid viscosity.
Hogendoorn, J. (Krohne New Technologies) | Boer, A. (Krohne New Technologies) | Bousche, O. (Krohne New Technologies) | Zoeteweij, M. (Krohne New Technologies) | Appel, M. (Shell) | de Jong, H. (Shell) | de Leeuw, R. (Shell)
This paper describes the concept and industrialization of a magnetic resonance based multiphase flow meter. It is demonstrated that magnetic resonance technology enables a very elegant and direct way of measuring multiphase flow.
The experimental data acquired during extensive tests with two prototypes, show good performance of the flow meter across the entire application range with respect to the determination of both the gas volume fractions, water liquid ratio and the individual phase flow rates. The experiments indicated that the sweet spot of the meter is at high water liquid ratios (WLR>85%). This is in accordance with theory.
Since the start of commercial applications of multiphase pumps, their installations have increased steadily. Today a number of reputable manufacturers offer a widespread pump range in regard to flow rate and pressure building capability. However, the foremost working principle still is the twin-screw technology.
Twin-screw pumps depend on liquid availability to seal the internal clearances and remove compression and friction heat generated. Different technical solutions to overcome this issue are available. Separation, storage and recirculation of produced liquid are a common way for this. However, pumps installed in parallel require special attention in regard to upstream flow splitting. This is especially true for multiphase pumps being fed by wells which are far away, as long gas slugs have to be envisaged.
The operation of multiphase pumps requires observing up- and downstream flow scenarios, as well as detailed knowledge of the entire (pumping) process. Furthermore potential solids production has to be taken into account.
Looped pipelines are evaluated as a method of reducing outlet flow rate fluctuations in multiphase pipelines operated in slug flow. The interference between the slug frequencies of the two pipelines is shown to be largely destructive in nature and acts to reduce outlet flow rate fluctuations. This configuration is shown to also provide advantages in the long-term operation of the pipeline system when pigging, corrosion, and leak consequence issues are considered for flow assurance design. The additional cost of a second pipeline may be minimal in terms of total project economics. A design example is given to illustrate the advantages of slug flow superposition.
This paper shows that most steady state gas-liquid pipe flow pattern representations can be visualized as two directed graphs, one for the macroscopic mass balance and another for the momentum balance. These directed graphs overlap around nodes where hydrodynamic slip is generated.
In order to understand the model structure of complex flow patterns, simple graphs can be reused to compose complex ones. Through this graphical and mathematical composition technique it is possible to find and understand analogies in the meaning of key variables and closures used by the models.
The presence of flow control components such as control valves and chokes along with elbows and Tees in close proximity to one another can lead to under-developed multiphase flows. In gas-producing fields, under-developed wet gas flows can exhibit localized high velocity regions and high liquid entrainment rates. If sand is present, such flows can potentially accelerate the erosion rates. In this work, the erosion of a carbon steel elbow downstream of an orifice plate in low liquid loading multiphase flows is discussed. Experiments were conducted in a 2-inch diameter multiphase flow loop. Erosion in the range of 0.04 to 0.14 mils/lb of sand was observed.
Gainville, M. (IFP Energies Nouvelles) | Cassar, C. (IFP Energies Nouvelles) | Sinquin, A. (IFP Energies Nouvelles) | Tzotzi, Ch. (Technip) | Parenteau, T. (Technip) | Turner, D. (ExxonMobil Development Company) | Greaves, D. (ExxonMobil Development Company) | Bass, R. (ExxonMobil Development Company) | Decrin, M-K. (Total E&P) | Glenat, P. (Total E&P) | Gerard, Fl. (Total E&P) | Morgan, J.E.P. (Woodside Energy Limited) | Zakarian, E. (Woodside Energy Limited)
There are many ways to prevent hydrate formation in production flowline and riser systems. The most common and traditionally trusted means of prevention is a combination of thermal insulation during production and depressurization with chemical injection and inert fluid flushing during shutdown, all of which can be operationally expensive, as well as environmentally and logistically demanding on offshore real estate. Recently, actively heated pipelines are being considered for hydrate plug prevention, whereby heating is applied to maintain the production fluid operating temperature above the hydrate formation temperature either continuously during normal production, or intermittently during shutdown and restart periods. However, the transition from maintaining a minimum temperature in the production system to hydrate plug dissociation by using active heating is a change requiring qualification prior to operator implementation. The purpose of the work described here is to validate the use of active heated pipelines for safe hydrate plug dissociation.
Improving flow simulators for multiphase flow with viscous oils is of concern for the oil industry as the available database for model validation is quite limited for the case of highly viscous oils. Severe slugging is a particular flow phenomenon where the quality of dynamic simulators is important. Two experimental series on severe slugging have been made in a S-shaped riser geometry (50mm inner diameter, 14 m length and 6.5 m height), one using viscous oil and the other using water as a reference. The experimental results are time recordings, amplitudes of pressure oscillations at riser base and slugging frequencies.
The experimental results are compared with simulations with a multiphase flow simulator.
This paper examines the critical flow rates of gas and liquid necessary to keep particles moving in a horizontal flow line with emphasis on flows with high gas-liquid ratios resulting in stratified flow with small liquid hold-up. Experimental results are presented for flows in 0.05 m and 0.1 m pipes varying particle size and shape. The types of particles used are sand and glass beads. Additionally, experiments are performed for two particle volume concentrations: 0.01 and 0.1 percent.
Soepyan, F.B. (The University of Tulsa) | Cremaschi, S. (The University of Tulsa) | Sarica, C. (The University of Tulsa) | Gao, H. (Chevron Energy Technology Company) | Subramani, H.J. (Chevron Energy Technology Company) | Kouba, G.E. (Chevron Energy Technology Company)
Transport of solids produced with oil and gas is desired to avoid flow assurance problems. Stratified flow is a challenging flow regime for solids transport because the solids are trapped in the relatively slow-moving liquid film. Our analysis revealed discrepancies between predictions of existing multiphase models and experimental observations. Thus, we extended single-phase models to stratified flow, assuming solids transport in the liquid phase, by evaluating the input characteristic length scales. We considered four length scales, and compared the models' predictions with experimental observations. The models' predictions are most accurate when the liquid film height is used as input.