Evaluation of Pressure Change While Steady-State Tripping

2014 ◽  
Author(s):  
Evgeny Podryabinkin ◽  
Ramadan Ahmed ◽  
Vladimir Tarasevich ◽  
Roland May
Keyword(s):  
Steady State ◽  
Numerical Solutions ◽  
Pressure Change ◽  
Laminar Flows ◽  
New Method ◽  
Analytical Models ◽  
Fluid Viscosity ◽  
Operational Parameters ◽  
Cylindrical Annulus ◽  
Fluid Properties

Excessive tripping speed in an uncased borehole increases the risk of having formation damage or influx of formation fluid (kick). However, if the tripping is performed at lower speeds, the operation requires more rig time. Hence, increased trip speed cuts expensive rig time. These opposing goals require thorough planning and optimization of the tripping operation to avoid operational problems and reduce financial expenditures. To maximize the tripping speed, accurate prediction of the pressure change occurring due to the axial pipe movement (surge or swab pressure) is necessary. The pressure change is influenced by the hole and string diameters, eccentricity, fluid properties and trip speed. The tripping speed is one of the operational parameters, which are regularly adjusted at the rig site. Analytical solutions exist only for special scenarios. The semi-analytical models for calculation of the steady-state pressure change cannot provide accurate predictions. They are mostly based on disputable assumptions which make the model to underestimate the pressure change. Most of the existing models are based on the parallel-plate approximation of the annular geometry. In another approach, the parameter, which reflects the amount of fluid which is dragged the direction of the string, assumed to be constant or calculated independent of the fluid viscosity. In this paper, accurate solutions were obtained from direct numerical simulation of flow in a cylindrical annulus with axial movement of the inner cylinder. The numerical algorithm is based on finite volume method and incorporates laminar flows of Newtonian, Power Law, Bingham Plastic and Herschel-Bulkley fluids. The method predicts the pressure change occurring in concentric and eccentric annuli with and without rotation of the inner cylinder. The goals of this work are to: i) study the influence of the eccentricity, fluid properties and tripping speed on the pressure change; and ii) evaluate the accuracy of the simplified approaches by comparing experimental data and numerical solutions, and determine their validity ranges. This paper presents a new method for finding trip-caused pressure change in the wellbore through systematic analysis of the numerical solutions. Parametric study was performed to examine the effects of different influential parameters on the pressure change. In addition, the results obtained from the numerical method are compared with the simplified solutions and the discrepancies are analyzed to show the improved accuracy of the new method.

Non-Isothermal Peristaltic Flow of Newtonian Fluids in a Circular Tube

2009 ◽  
Author(s):  
M. S. Yun ◽  
B. P. Huynh
Keyword(s):  
Reynolds Number ◽  
Flow Pattern ◽  
Circular Tube ◽  
Pressure Change ◽  
Peristaltic Flow ◽  
Isothermal Flow ◽  
Newtonian Fluids ◽  
Fluid Viscosity ◽  
Fluid Properties ◽  
Isothermal Case

Non-isothermal peristaltic flow of Newtonian fluids in a circular tube is investigated numerically, using a commercial Computational Fluid Dynamics (CFD) software package. Simulation is performed over a range of Reynolds-number values, up to 1000. Temperature affects the flow field via fluid viscosity, which is assumed to decrease exponentially with temperature. Other fluid properties are assumed to be constant, and are similar to those of an oil. Allowing for temperature effects alters significantly the flow pattern and reduces pressure change. In the crest region, recirculation appears in non-isothermal flow at a much smaller Reynolds number Re than in isothermal flow. Influence of the Reynolds number itself is also reduced significantly, such that the flow pattern changes very little with increasing Re, in contrast to the isothermal case. Similarly, in non-isothermal flow, flow pattern is unchanged at different flow rate. This is also in contrast to the isothermal situation.

An Experimental Model Investigation of the Opening of a Collapsed Untethered Pulmonary Airway

1995 ◽  
Vol 117 (3) ◽  
pp. 245-253 ◽  
Author(s):  
Matthew L. Perun ◽  
Donald P. Gaver
Keyword(s):  
Surface Tension ◽  
Steady State ◽  
Structural Characteristics ◽  
Stable Steady State ◽  
Effective Diameter ◽  
Fluid Viscosity ◽  
Two Dimensional ◽  
Fluid Properties ◽  
Wall Deformation ◽  
Fluid Film Thickness

We developed an essentially two-dimensional planar benchtop model of an untethered collapsed airway to investigate the influence of fluid properties (viscosity, μ and surface tension, γ) and the structural characteristics (effective diameter, D, longitudinal tension, T, and fluid film thickness, H) on airway reopening. This simplified model was used to quantify the relationship between wall deformation and meniscus curvature during reopening. We measured the pressure (P) required to move the meniscus at a constant velocity (U), and found the dimensionless post-startup pressure (PD/γ) increased monotonically with the capillary number (Ca = μU/γ). Startup pressures depend on the fluid viscosity and piston acceleration, and may significantly increase reopening pressures. Consistently stable steady-state pressures existed when Ca > 0.5. D was the most dominant structural characteristic, which caused an increase in the post-startup pressure (P) for a decrease in D. An increase in H caused a slight decrease in the reopening pressure, but a spatial variation in H resulted in only a transient increase in pressure. T did not significantly affect the reopening pressure. From our planar two-dimensional experiments an effective yield pressure of 3.69 γ/D was extrapolated from the steady-state pressures. Based on these results, we predicted airway pressures and reopening times for axisymmetrically collapsed airways under various disease states. These predictions indicate that increasing surface tension (as occurs in Respiratory Distress Syndrome) increases the yield pressure necessary to reopen the airways, and increasing viscosity (as in cystic fibrosis) increases the time to reopen once the yield pressure has been exceeded.

A Variable Wave Speed Technique for the Steady-State Analysis of Low-Clearance Gas Bearings

1977 ◽  
Vol 99 (3) ◽  
pp. 339-344 ◽  
Author(s):  
J. W. White
Keyword(s):  
Steady State ◽  
Pressure Wave ◽  
Wave Speed ◽  
Numerical Solutions ◽  
Finite Width ◽  
Fluid Viscosity ◽  
Rigid Boundary ◽  
Steady State Analysis ◽  
Gas Bearings ◽  
State Analysis

A method is described which utilizes an artificial fluid viscosity as a means of adjusting the pressure wave speed in asymptotic steady-state analysis of gas bearings. The approach is shown to be useful for producing steady numerical solutions of low-clearance bearings with minimum computation. The technique is first developed for a rigid boundary step bearing of infinite width and then extended to the finite width case by a semi-implicit solution procedure. Last, the method is shown to be useful for the analysis of foil bearings in which case the pressure wave speed is “tuned” to that of the foil wave so as to produce an optimum computational approach to steady state.

A new method to solve a non-steady-state multispecies biofilm model

1993 ◽  
Vol 55 (6) ◽  
pp. 1039-1061 ◽  
Author(s):  
Vincent Gadani ◽  
Pierre Villon ◽  
Jacques Manem ◽  
Bruce Rittmann
Keyword(s):  
Steady State ◽  
New Method ◽  
Biofilm Model ◽  
Multispecies Biofilm

Performance Analysis for a Gantry Crane System (GCS) Using Priority-Based Fitness Scheme in Binary Particle Swarm Optimization

2014 ◽  
Vol 903 ◽  
pp. 285-290 ◽  
Author(s):  
Hazriq Izzuan Jaafar ◽  
Zaharuddin Mohamed ◽  
Amar Faiz Zainal Abidin ◽  
Zamani Md Sani ◽  
Jasrul Jamani Jamian ◽  
...  
Keyword(s):  
Particle Swarm Optimization ◽  
Steady State ◽  
Control Structure ◽  
Lagrange Equation ◽  
Particle Swarm ◽  
New Method ◽  
Gantry Crane ◽  
Binary Particle Swarm Optimization ◽  
Optimal Parameters ◽  
Swarm Optimization

This paper presents development of an optimal PID and PD controllers for controlling the nonlinear Gantry Crane System (GCS). A new method of Binary Particle Swarm Optimization (BPSO) algorithm that uses Priority-based Fitness Scheme is developed to obtain optimal PID and PD parameters. The optimal parameters are tested on the control structure to examine system responses including trolley displacement and payload oscillation. The dynamic model of GCS is derived using Lagrange equation. Simulation is conducted within Matlab environment to verify the performance of the system in terms of settling time, steady state error and overshoot. The result not only confirmed the successes of using new method for GCS, but also shows the new method performs more efficiently compared to the continuous PSO. This proposed technique demonstrates that implementation of Priority-based Fitness Scheme in BPSO is effective and able to move the trolley as fast as possible to the desired position with low payload oscillation.

Estimation of the rate of appearance in the non-steady state with a two-compartment model

1992 ◽  
Vol 263 (2) ◽  
pp. E400-E415 ◽  
Author(s):  
A. Mari
Keyword(s):  
Steady State ◽  
Time Course ◽  
Specific Activity ◽  
Glucose Production ◽  
Compartment Model ◽  
New Method ◽  
Two Compartment Model ◽  
Glucose Clamp Technique ◽  
Glucose Output ◽  
The Relationship

A simple tracer-based method for calculating the rate of appearance of endogenous substances in the non-steady state, free from the inconsistencies of Steele's equation, is still lacking. This paper presents a method based on a two-compartment model by which the rate of appearance can be calculated with only a modest increase in complexity over Steele's approach. An equation is developed where the rate of appearance is expressed as a sum of three terms: a steady-state term, a term for the first compartment, and a term for the second compartment. The formula employs three parameters and makes the relationship between rate of appearance and specific activity changes explicit. An equation is also provided for estimating the error of the method in each individual run. The algorithm can be implemented with a spreadsheet on a personal computer. Simulated and experimental data obtained by the hyperinsulinemic euglycemic glucose clamp technique were used as a test. The accuracy with which the time course of glucose production could be reconstructed was clearly better than that using Steele's equation. Marked negative values for endogenous glucose output were calculated with Steele's equation but not with the new method. The characteristics of generality, simplicity, and accuracy and the availability of an error estimate make this new method suitable for routine application to non-steady-state tracer analysis.

Verification of Finite Volume Computations on Steady-State Fluid Flow and Heat Transfer

2001 ◽  
Vol 124 (1) ◽  
pp. 11-21 ◽  
Author(s):  
J. Cadafalch ◽  
C. D. Pe´rez-Segarra ◽  
R. Co`nsul ◽  
A. Oliva
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Steady State ◽  
Finite Volume ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Independent Solution ◽  
Post Processing ◽  
Square Duct ◽  
Flow And Heat Transfer

This work presents a post-processing tool for the verification of steady-state fluid flow and heat transfer finite volume computations. It is based both on the generalized Richardson extrapolation and the Grid Convergence Index GCI. The observed order of accuracy and a error band where the grid independent solution is expected to be contained are estimated. The results corresponding to the following two and three-dimensional steady-state simulations are post-processed: a flow inside a cavity with moving top wall, an axisymmetric turbulent flow through a compressor valve, a premixed methane/air laminar flat flame on a perforated burner, and the heat transfer from an isothermal cylinder enclosed by a square duct. Discussion is carried out about the certainty of the estimators obtained with the post-processing procedure. They have been shown to be useful parameters in order to assess credibility and quality to the reported numerical solutions.

Buoyancy-driven crack propagation: the limit of large fracture toughness

2007 ◽  
Vol 580 ◽  
pp. 359-380 ◽  
Author(s):  
S. M. ROPER ◽  
J. R. LISTER
Keyword(s):  
Fracture Toughness ◽  
Pressure Gradient ◽  
Viscous Flow ◽  
Numerical Solutions ◽  
Elastic Solid ◽  
Propagation Rate ◽  
Fluid Viscosity ◽  
Viscous Effects ◽  
Vertical Propagation ◽  
Viscous Pressure

We study steady vertical propagation of a crack filled with buoyant viscous fluid through an elastic solid with large effective fracture toughness. For a crack fed by a constant flux Q, a non-dimensional fracture toughness K=Kc/(3μQm3/2)1/4 describes the relative magnitudes of resistance to fracture and resistance to viscous flow, where Kc is the dimensional fracture toughness, μ the fluid viscosity and m the elastic modulus. Even in the limit K ≫ 1, the rate of propagation is determined by viscous effects. In this limit the large fracture toughness requires the fluid behind the crack tip to form a large teardrop-shaped head of length O(K2/3) and width O(K4/3), which is fed by a much narrower tail. In the head, buoyancy is balanced by a hydrostatic pressure gradient with the viscous pressure gradient negligible except at the tip; in the tail, buoyancy is balanced by viscosity with elasticity also playing a role in a region within O(K2/3) of the head. A narrow matching region of length O(K−2/5) and width O(K−4/15), termed the neck, connects the head and the tail. Scalings and asymptotic solutions for the three regions are derived and compared with full numerical solutions for K ≤ 3600 by analysing the integro-differential equation that couples lubrication flow in the crack to the elastic pressure gradient. Time-dependent numerical solutions for buoyancy-driven propagation of a constant-volume crack show a quasi-steady head and neck structure with a propagation rate that decreases like t−2/3 due to the dynamics of viscous flow in the draining tail.

A Cognitive Data-Driven Single-Well Modeling Workflow for Reservoir Deliverability Predictions – Expanding the Wireline Formation Tester Application Envelope

2021 ◽  
Author(s):  
Abdul Bari ◽  
Mohammad Rasheed Khan ◽  
M. Sohaib Tanveer ◽  
Muhammad Hammad ◽  
Asad Mumtaz Adhami ◽  
...  
Keyword(s):  
Reservoir Characterization ◽  
Production Performance ◽  
Data Driven ◽  
Analytical Models ◽  
Production Model ◽  
Reservoir Evaluation ◽  
Fluid Properties ◽  
Petrophysical Model ◽  
Single Well ◽  
Data Driven Approach

Abstract In today's dynamically challenging E&P industry, exploration activities demand for out-of-the-box measures to make the most out of the data available at hand. Instead of relying on time consuming and cost-intensive deliverability testing, there is a strong push to extract maximum possible information from time- and cost-efficient wireline formation testers in combination with other openhole logs to get critical reservoir insight. Consequently, driving efficiency in the appraisal process by reducing redundant expenditures linked with reservoir evaluation. Employing a data-driven approach, this paper addresses the need to build single-well analytical models that combines knowledge of core data, petrophysical evaluation and reservoir fluid properties. Resultantly, predictive analysis using cognitive processes to determine multilayer productivity for an exploratory well is achieved. Single Well Predictive Modeling (SWPM) workflow is developed for this case which utilizes plethora of formation evaluation information which traditionally resides across siloed disciplines. A tailor-made workflow has been implemented which goes beyond the conventional formation tester deliverables while incorporating PVT and numerical simulation methodologies. Stage one involved reservoir characterization utilizing Interval Pressure Transient Testing (IPTT) done through the mini-DST operation on wireline formation tester. Stage two concerns the use of analytical modeling to yield exact solution to an approximate problem whose end-product is an estimate of the Absolute Open Flow Potential (AOFP). Stage three involves utilizing fluid properties from downhole fluid samples and integrating with core, OH logs, and IPTT answer products to yield a calibrated SWPM model, which includes development of a 1D petrophysical model. Additionally, this stage produces a 3D simulation model to yield a reservoir production performance deliverable which considers variable rock typing through neural network analysis. Ultimately, stage four combines the preceding analysis to develop a wellbore production model which aids in optimizing completion strategies. The application of this data-driven and cognitive technique has helped the operator in evaluating the potential of the reservoir early-on to aid in the decision-making process for further investments. An exhaustive workflow is in place that can be adopted for informed reservoir deliverability modeling in case of early well-life evaluations.

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