Gas Migration in Wellbores During Pressurized Mud Cap Drilling PMCD

2021 ◽  
Author(s):  
Ganesh Arunkumar Samdani ◽  
Sai Sashankh Rao ◽  
Vishwas Paul Gupta
Keyword(s):  
Multiphase Flow ◽  
Field Data ◽  
Gas Migration ◽  
Field Scale ◽  
Cfd Simulations ◽  
Migration Rates ◽  
Parametric Effects ◽  
Slow Moving ◽  
Gas Volume ◽  
Migration Velocities

Abstract In PMCD operations, reservoir gas is expected to migrate uphole, and the uncertainty in gas migration rates under downhole conditions leads to challenges in planning logistics and fluid requirements. Estimates of migration velocities based on current methods (e.g. Taylor-bubble correlation) are highly conservative and involves simplifying assumptions. This paper presents a systematic approach to understanding the fundamentals of gas migration in wellbores, relates it to field data, and provides recommendations to improve PMCD design and planning. Our approach includes analysis of PMCD field data, multiphase flow literature and computational flow simulations. The field data on gas migration is used to establish the field-scale parametric effects and observed trends. Multiphase flow literature is used to qualitatively understand some of these parametric effects at downhole conditions. A comparison between multiphase flow literature and field data overwhelmingly demonstrates the gaps in understanding of underlying physics. 3-dimensional multiphase CFD simulations for a representative well geometry and downhole conditions are used to understand gas migration physics at downhole conditions and the reasons for its sensitivity to different conditions. CFD simulations showed a strong impact of pressure on bubble breakup. As a result, the gas migrates as a slow-moving swarm of smaller bubbles. The formation of smaller bubbles from a given gas volume is a rate dependent process and requires a finite time to reach to an equilibrium/steady-state. The field conditions provide both high downhole pressure and sufficient length-scale for formation of smaller slow-moving bubbles. For the same reason, small scale-experiments are limited in their application for field-scale designs due to use of low pressure and/or insufficient length-scales. The CFD results also compare well with field data in showing ~30% holdup of migrating gas at low migration rates and negligible effect of rotation and wellbore geometry i.e. annulus vs openhole. The extent and rate of disintegration of gas volume (bubble) has a negative correlation with well inclination, liquid viscosity, and surface tension. The rheology and liquid viscosity also affect the ability of liquid to sweep the gas back into the reservoir and therefore it is expected to have an optimum range for a given PMCD application. Use of high viscosity fluids for typical downhole well conditions is counterproductive and results in higher gas migration rates and therefore not recommended. The understanding of downhole physics is expected to improve logistics/storage/ planning/fluid choice and lead to lower gas migration rates and reliable operation. The same approach can be applied to other operations and scenarios where gas migration velocities are a key design factor.

Multiphase Flow in Circular and Triangular Pipes: Examining Flow Characteristics, Sand Erosion and Heat Transfer Via CFD and Experimental Work

2021 ◽  
Author(s):  
Ronald E. Vieira ◽  
Thiana A. Sedrez ◽  
Siamack A. Shirazi ◽  
Gabriel Silva
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Experimental Work ◽  
Heat Exchangers ◽  
Flow Patterns ◽  
Cfd Simulations ◽  
Liquid Distribution ◽  
Circular Pipes ◽  
Sand Erosion ◽  
Sand Flow

Abstract Air-water two-phase flow in circular pipes has been studied by many investigators. However, investigations of multiphase flow in non-circular pipes are still very rare. Triangular pipes have found a number of applications, such as multiphase flow conditioning, erosion mitigation in elbows, compact heat exchanges, solar heat collectors, and electronic cooling systems. This work presents a survey of air-water and air-water-sand flow through circular and triangular pipes. The main objective of this investigation is to study the potential effects of triangular pipe geometry on flow patterns, slug frequency, sand erosion in elbows, and heat transfer in multiphase flow. Firstly, twenty-three experiments were performed for horizontal air-water flow. Detailed videos and slug frequency measurements were collected through circular and triangular clear pipes to identify flow patterns and create a database for these pipe configurations. The effect of corners of the triangular pipe on the liquid distribution was investigated using two different orientations of triangular pipe: apex upward and downward and results of triangular pipes were compared to round tubes. Secondly, ultrasonic wall thickness erosion measurements, paint removal studies, and CFD simulations were carried out to investigate the erosion patterns and magnitudes for liquid-sand and liquid-gas-sand flows in circular and triangular elbows with the same radius of curvature and cross-sectional area. Thirdly, heat transfer rates for liquid flows were also simulated for both circular and triangular pipe cross-sections. Although similar flow patterns are observed in circular and triangular pipe configurations, the orientation of the triangular pipes seems to have an effect on the liquid distribution and slug frequency. For higher liquid rates, slug frequencies are consistently lower in the triangular pipe as compared to the circular pipe. Similarly, the triangular elbow offers better flow behavior as compared to circular elbows when investigated numerically with similar flow rates for erosion patterns for both liquid-sand flow and liquid-gas-sand flows. Experimental and CFD results show that erosion in the circular elbow is about three times larger than in the triangular elbow. Paint studies results validated erosion patterns and their relations with particle impacts. Finally, heat transfer to/from triangular pipes is shown to be more efficient than in circular pipes, making them attractive for compact heat exchangers and heat collectors. This paper represents a novel experimental work and CFD simulations to examine the effects of pipe geometries on multiphase flow in pipes with several practical applications. The present results will help to determine the efficiency of utilizing triangular pipes as compared to circular pipes for several important applications and field operations such as reducing slug frequencies of multiphase flow in pipes, and reducing solid particle erosion of elbows, and also increasing the efficiency of heat exchangers.

Application of Kalman filter to reproduce displacement pattern along with the unknown soil properties of slow-moving landslides

2021 ◽  
Author(s):  
Mohit Mishra ◽  
Gildas Besançon ◽  
Guillaume Chambon ◽  
Laurent Baillet ◽  
Arnaud Watlet ◽  
...  
Keyword(s):  
Time Series ◽  
Kalman Filter ◽  
Water Table ◽  
Field Data ◽  
Friction Angle ◽  
Early Warning Systems ◽  
Economic Losses ◽  
Slide Block ◽  
Slow Moving ◽  
Parameter Values

<p><span>Landslides display heterogeneity in movement types and rates, ranging from creeping motion to catastrophic acceleration. In most of the catastrophic events, rocks, debris, or soil can travel at several tens of meters per year speed, causing significant cost in life losses, infrastructure, economy, and ecosystem of the region. In contrast, slow-moving landslides display typical velocities scaling from few centimeters to several meters per year. Although slow-moving landslides rarely claim life losses, they can still cause considerable damage to public and private infrastructure. Sometimes these slow, persistent landslides eventually lead to catastrophic acceleration, e.g., clayey landslides are prone to these transitions. Such events need to be detected by Early Warning Systems (EWS) in advance to take timely actions to reduce life and economic losses. Several approaches are proposed to forecast the time of failure; still, there is a need to improve prediction strategies and EWS’s. </span></p><p><span>Here we present state and parameter estimation for a simplified viscoplastic sliding model of a landslide using a Kalman filter approach, which is termed as an observer problem in control theory. The model under investigation is based on underlying mechanics (physics-based model) that portray a landslide behavior. In this model, a slide block is assumed to be placed on an inclined surface, where landslide (slide block) motion is regulated by basal pore fluid pressure and opposed by sliding resistance governed by friction, cohesion, and viscosity. This model is described by an Ordinary Differential Equation (ODE) with displacement as a state and landslide material and geometrical properties as parameters. In this approach, known parameter values (landslide geometrical parameters and some material properties) and water table height time-series are provided as input. Finally, two illustrative examples validate the presented approach: i) a synthetic case study and ii) Hollin hill landslide (Uhlemann et al., 2016) field data. </span></p><p><span>In both examples, displacement, friction angle, and viscosity are well estimated from known parameter values, water table height time-series, and displacement measurements. In the simulation results for the Hollin Hill field data, it is observed that friction angle almost remains constant while viscosity varies significantly through time.</span></p><p> </p><p><span>Uhlemann, S., Smith, A., Chambers, J., Dixon, N., Dijkstra, T., Haslam, E., Meldrum P., Merritt, A., Gunn, D., and Mackay, J., (2016). Assessment of ground-based monitoring techniques applied to landslide investigations. </span><em><span>Geomorphology</span></em><span>, 253, 438-451. doi:10.1016/j.geomorph.2015.10.027.</span></p>

A 3D Transient Model for the Multiphase Flow in a Progressing-Cavity Pump

SPE Journal ◽  
2016 ◽  
Vol 21 (04) ◽  
pp. 1458-1469 ◽  
Author(s):  
Victor W. de Azevedo ◽  
João A. de Lima ◽  
Emilio E. Paladino
Keyword(s):  
Multiphase Flow ◽  
Flow Rate ◽  
Homogeneous Model ◽  
Volumetric Flow Rate ◽  
Volumetric Efficiency ◽  
Two Phase ◽  
Transient Model ◽  
Viscous Losses ◽  
Constant Displacement ◽  
Gas Volume

Summary This paper presents the development of a computational-fluid-dynamics (CFD) model for the 3D transient two-phase flow within a progressing-cavity pump (PCP). The model implementation was only possible because of the meticulous mesh-generation and mesh-motion algorithm, previously published by the authors, which is briefly described herein. In this algorithm, a structured mesh was generated by defining all nodes’ positions and connectivities, for each rotor position by means of FORTRAN subroutines, which were embodied into ANSYS CFX software. The model is capable of predicting accurately the volumetric efficiency and the viscous losses, and it provides detailed information of pressure and velocity fields and void distribution along the pump. Such information could be of fundamental importance for product development and/or optimization for field operation. In field applications, the common situation is that in which the oil comes into the pump accompanied with free gas, which characterizes a multiphase flow. Simplified models on the basis of the calculation of the backflow or “slippage,” which is subtracted from the displaced flow rate, fail to characterize the PCP performance under multiphase conditions because the slip is variable along the pump. In this model, the governing equations were solved with an element-based finite-volume method in a moving mesh. The Eulerian-Eulerian approach, considering the homogeneous model, is used to model the flow of the gas/liquid mixture. The compressibility of the gas is taken into account, which is one of the main shortcomings in positive/constant displacement pumps. The effects of the different gas-volume fractions (GVFs) in pump volumetric efficiency, pressure distribution, power, slippage flow rate, and volumetric flow rate were analyzed, and some new insights are presented about the slippage in PCPs operating in multiphase conditions. The results show that the developed model is capable of reproducing pump dynamic behavior under multiphase-flow conditions performed early in experimental works.

scholarly journals A Study of Pressure Gradient in Multiphase Flow in Vertical Pipes

2019 ◽  
Vol 4 (1) ◽  
pp. 54-59
Author(s):  
David Nwobisi Wordu ◽  
Felix J. K. Ideriah ◽  
Barinyima Nkoi
Keyword(s):  
Pressure Drop ◽  
Multiphase Flow ◽  
Pressure Gradient ◽  
Performance Optimization ◽  
Field Data ◽  
Oil And Gas ◽  
Liquid Velocity ◽  
Petroleum Industry ◽  
Well Performance ◽  
Flowing Fluid

The study of multiphase flow in vertical pipes is aimed at effective and accurate design of tubing, surface facilities and well performance optimization for the production of oil and gas in the petroleum industry by developing a better approach for predicting pressure gradient. In this study, field data was analyzed using mathematical model, multiphase flow correlations, statistical model, and computer programming to predict accurately the flow regime, liquid holdup and pressure drop gradient which are important in the optimization of well. A Computer programme was used to prediction pressure drop gradient. Four dimensionless parameters liquid velocity number (Nlv), gas velocity number (Ngv), pipe diameter number (Nd), liquid viscosity number (Nl), were chosen because they represent an integration of the two dominant components that influence pressure drop in pipes. These dominant component are flow channel/media and the flowing fluid. The model was found to give a fit of 100% to the selected data points. Hagedorn & Brown, Griffith &Wallis correlations and model were compared with field data and the overall pressure gradient for a total depth of 10000ft was predicted. The predicted pressure gradient measured was found to be 0.320778psi/ft, Graffith& Wallis gave 0.382649Psi/ft, Hagedorn & Brown gave 0.382649Psi/ft; whereas generated model gave 0.271514Psi/ft. These results indicate that the model equation generated is better and leads to a reasonably accurate prediction of pressure drop gradient according to measured pressure gradient.

CFD Simulation of Segregation in Particulate Multiphase Flows With Binary Solids

2005 ◽  
Author(s):  
Zuoxin Hao
Keyword(s):  
Multiphase Flow ◽  
Cfd Simulation ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Primary Objective ◽  
Cfd Simulations ◽  
Separation Processes ◽  
Solid Mixture ◽  
Computational Fluid Dynamics Cfd ◽  
Realistic Prediction

Segregation in particulate multiphase flow with binary solid mixture has extensive applications in industrial separation processes. Up to now there have been few attempts towards numerical simulation of segregation in particulate multiphase flow with binary mixture due to complexity of the problem. In view of this, the primary objective of present work is to simulate the problem by computational fluid dynamics (CFD) and to validate by comparison with experimental measurements. Eulerian-Eulerian approach, incorporating the granular temperature, an essential ingredient in the solids pressure and solids viscosity formulation, was used to model the flow field of multiphase flow and was solved by Fluent 6.0. The CFD simulation results have been validated by experiments of liquid fluidization of binary solid mixtures. Validation results show that CFD simulation predict segregation and solid volume fraction profile precisely, and in addition, it can supply a more realistic prediction of other hydrodynamic features of the multiphase flow, such as velocity vector of all phases and pressure drop. The success of such CFD simulations opens doors for many potential studies.

Multiphase sand erosion in standard elbows

2015 ◽  
Vol 55 (1) ◽  
pp. 371
Author(s):  
Chong Yau Wong ◽  
Amir Zamberi ◽  
Amira Shaffee ◽  
Zurita Johar ◽  
Maharon Jadid ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Oil And Gas ◽  
Hot Spot ◽  
Internal Surface ◽  
Internal Erosion ◽  
Pipe System ◽  
Surface Profiling ◽  
Sand Erosion ◽  
Erosion Modelling ◽  
Gas Volume

Standard elbows are used to redirect multiphase flows in oil and gas facilities. Internal erosion of the pipe walls is expected when produced solids are present in the pipe system. The literature widely documents erosion modelling through empirical and numerical methodologies validated with experimental data on elbow erosion. There are no studies documenting the full internal surface of standard elbows in multiphase flow erosion. This peer-reviewed paper fills that knowledge gap through experimental erosion modelling of standard elbows at various multiphase flow conditions. The results provide a source of validation for numerical and analytical methodologies. Surface profiling of standard elbows at gas volume fractions (GVFs) from zero to one are studied. Results suggest that erosion hot spots for all GVFs are located past an angle of approximately 45° from the flow inlet plane. In gas only flows, moderate levels of erosion occur upstream of the erosion hot spot. All GVF conditions exhibit moderate levels of erosion downstream of the erosion hot spot. In liquid only flows, the erosion hot spot is at the extrados in the vicinity of the elbow outlet plane, and is not easily detectable by ultrasonic probes. Comparison of multiphase experimental erosion pattern is made with computational fluid dynamics multiphase erosion simulations. A new relationship between the erosion rate of standard elbows and the reference cylinder-in-pipe data is proposed.

Field Examples of Gas Migration Rates

1996 ◽  
Author(s):  
R.D. Grace ◽  
J.L. Shursen
Keyword(s):  
Gas Migration ◽  
Migration Rates
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