Lift Optimization Research Articles

Gas Lift Optimization of an Oil Field in Malaysia

Gas lift is an artificial lift method which is commonly used in offshore operation with sufficient gas sources as it consumes minimum space on the platform. Gas lift operates by injecting a high pressure gas down through the tubing casing annulus of a well and the injected gas enters the tubing through a gas lift valve installed on the tubing. Gas lift increases production by two means, density reduction of oil column inside the tubing so that the flowing bottom-hole pressure which is affected by the hydrostatic pressure of the fluid column is reduced and by providing external energy to the oil as the gas expends.Reducing the bottom-hole pressure will improve the drawdown of the well. A production well is modelled by using a production modelling program, Integrated Production Modeling (IPM) Prosper to analyze the production performance at various conditions. A base case model is developed from the production data of an actual oil field to simulate the performance of the actual well without gas lift system. Later, the gas lift is added to the model and the performance was compared with the base case model. The gas parameter was also studied to determine the optimum injection gas condition for maximum oil production. The gas injected at 1490m can be achieved by injecting the gas with 1200 psi, l300 psi or 1400 psi. However, the optimum gas injection pressure was determined to be at 1400 psi as the design shows that the required unloading stage is the least. The optimum gas injection rate was determined at 5 MMscf/d with the estimated net revenue is the highest. For injection gas gravity, the lighter gas was determined to be the optimum selection since it gives significant reduction of FBHP (Flowing Bottom Hole Pressure) with less hydrostatic pressure inside the tubing column.

A Study of Continuous Flow Gas Lift System Using CFD

Gas lift optimization has been a point of interest for some decades in order to increase production in oil fields. Despite that there are still lacks of user friendly software in gas lift optimization. The ultimate goal of this study is to develop user friendly program using commercial Computational Fluid Dynamics (CFD) software for optimization of continuous flow gas lift for single well. GAMBIT 2.3.16 was used for modelling the tubing string prior the simulation process. Two-phase CFD calculations using Eulerian–Eulerian model and commercial CFD package FLUENT 6.0 were employed to calculate the gas-liquid flow in the string. The depth and the rate of gas injection were the main parameter tested. The simulation results showed that the highest velocity of flowing fluid was observed when the gas was injected at the lowest point, which is at 5 m from the casing shoe in this study. The velocity of flowing fluid was increased by 1.7% when the gas injection rate increased 20%. This interrelationship was observed with regard of the decrease in liquid column density. CFD is capable in aiding faster continuous flow gas lift optimization process.

Lifting Point Optimization of Large Steel Truss on the Principle of Minimum Potential Energy

The integral hoisting construction technology of large steel truss has been widely used in the steel structure construction. Based on the principle of strain energy, the feasibility analysis on lifting point optimization of Wuhan public house’s large steel truss was conducted. It expounded the integral lifting construction technology of Wuhan public house’s large steel truss. Through the 12 different methods of lifting point setting and the application of finite element analysis software SAP2000, it discussed the optimization method of hoisting points of large steel truss on the principle of minimum potential energy. It achieved the change rule of the whole strain energy of steel truss. The scheme of 10 lifting points was identified on the economy and construction conditions. The stress state, the structural deformation state and the steady mode was analyzed under the optimum lifting point condition. The results meet the design and construction requirements, and this research method can provide the certain reference value for similar engineering.

Optimum Tower Crane Selection and Supporting Design Management

To optimize tower crane selection and supporting design, lifting requirements (as well as stability) should be examined, followed by a review of economic feasibility. However, construction engineers establish plans based on data provided by equipment suppliers since there are no tools with which to thoroughly examine a support design's suitability for various crane types, and such plans lack the necessary supporting data. In such cases it is impossible to optimize a tower crane selection to satisfy lifting requirements in terms of cost, and to perform lateral support and foundation design. Thus, this study is intended to develop an optimum tower crane selection and supporting design management method based on stability. All cases that are capable of generating an optimization of approximately 3,000 ˜ 15,000 times are calculated to identify the candidate cranes with minimized cost, which are examined. The optimization method developed in the study is expected to support engineers in determining the optimum lifting equipment management.

Oil Well Characterization and Artificial Gas Lift Optimization Using Neural Networks Combined with Genetic Algorithm

This paper examines the characterization of six oil wells and the allocation of gas considering limited and unlimited case scenario. Artificial gas lift involves injecting high-pressured gas from the surface into the producing fluid column through one or more subsurface valves set at predetermined depths. This improves recovery by reducing the bottom-hole pressure at which wells become uneconomical and are thus abandoned. This paper presents a successive application of modified artificial neural network (MANN) combined with a mild intrusive genetic algorithm (MIGA) to the oil well characteristics with promising results. This method helps to prevent the overallocation of gas to wells for recovery purposes while also maximizing oil production by ensuring that computed allocation configuration ensures maximum economic accrual. Results obtained show marked improvements in the allocation especially in terms of economic returns.

Effective Method to Predict Installation of Plunger in a Gas Well

Liquid loading is a common problem for most of the mature gas wells. Over years, many methods have been developed to solve this problem. One of the widely used methods is plunger lift, which requires shut-in of the gas well for a period of time. Then, the well is reopened, and it is expected that the natural energy of the well will push the plunger to the surface carrying the liquid with it. Optimization of the plunger lift requires that the well be shut-in for a period of time as short as possible, followed by production of gas for as long as possible. This note examines the requirement for a successful shut-in of a well so that the well can sustain the production for a longer time. The note also discusses the condition under which the well will not sustain the production and the plunger lift will not be effective. The analysis is confirmed with several field examples, which will be shown in this note.

센싱정보를 활용한 초고층 건설용 리프트 최적화 운행 시스템 개발

건축물이 고층화, 대형화 될수록 수직 양중 계획 및 운영에 관한 중요성이 부각되고 있다. 이에 프로젝트 초기 단계에 실제 모델과 유사한 건설용 리프트 양중계획을 수립하려는 노력이 계속되고 있지만 프로젝트 착수 후 리프트 운행을 컨트롤 할 수 있는 시스템은 부재한 실정이다. 따라서 본 논문에서는 건설용 리프트 운영 효율증대를 위하여 센서를 사용한 리프트 운행 정보를 수집하고 실시간 분석이 가능한 건설용 리프트 최적화 운행 시스템 개발을 실시 및 검증 단계를 수행하여, 양중 효율의 지표가 되는 사용자 대기 시간의 단축을 도모하고 향후 무인 스마트 리프트의 초석이 되는 시스템을 제시하고자 한다. As recent buildings have been more higher and larger, construction vertical lifting planning and operation is a key factor for successful project in tall building. Although many studies have been trying to set up a construction lifting planning system at early stage, there's not existing a control real-time lift operation control system with respect to during construction stage. Therefore, In this study, we use the sensor device to collect the lift operating data for improvement of lift operation efficiency and develope optimum lift operating system which can perform real-time analysis. Finally, we verify the efficiency of proposed system through comparison between realtime operating data and simulated data using proposing system. In this paper, the proposed system show more efficient moving line compared with previous system. This can contribute to development of unmanned lift system.

Gas Lift Optimization: Using Least Square Method and Solver

In this study a model was developed using least square method. This model was tested for reliability and it was found to be reliable for prediction. We now use this model for optimization of oil production.The following reports was obtained after optimization.Answer report: Oil produced original value was 3471,251,263.00STB/Dayand the final value was 1347,252, 519.25STB/Day.Sensitivity Report: Allowable increase in liquid injected was 32.19893491bbl/day and Allowable decrease in liquid injected was 0.591566837bbl/day. Also allowable increase in water cut was 1E+30bbl and allowable decrease in water cut was 96.59680522bbl/day.Limit Report: liquid injected lower limit -1.03228E-10bbl and target result was not available and. The water cut target was 0. 1347252519bbl.It is evident that a real optimization model that can optimize oil production for different amount of liquid injected and water cut has been developed. Such a model can provide the oil industries in the Country important information about the sensitivity of the optimal solution.Keywords: Model,optimization,Limits,Sensitivity,Production

Scaling law and enhancement of lift generation of an insect-size hovering flexible wing

We report a comprehensive scaling law and novel lift generation mechanisms relevant to the aerodynamic functions of structural flexibility in insect flight. Using a Navier-Stokes equation solver, fully coupled to a structural dynamics solver, we consider the hovering motion of a wing of insect size, in which the dynamics of fluid-structure interaction leads to passive wing rotation. Lift generated on the flexible wing scales with the relative shape deformation parameter, whereas the optimal lift is obtained when the wing deformation synchronizes with the imposed translation, consistent with previously reported observations for fruit flies and honeybees. Systematic comparisons with rigid wings illustrate that the nonlinear response in wing motion results in a greater peak angle compared with a simple harmonic motion, yielding higher lift. Moreover, the compliant wing streamlines its shape via camber deformation to mitigate the nonlinear lift-degrading wing-wake interaction to further enhance lift. These bioinspired aeroelastic mechanisms can be used in the development of flapping wing micro-robots.

On Generalized Reduced Gradient method with multi-start and self-optimizing control structure for gas lift allocation optimization

In most of the gas lifted oil fields, multiple oil wells share lift gas from a common gas distribution source. The lift gas should be distributed optimally among the wells to maximize total oil production. In this paper, a nonlinear dynamic model of the oil field is developed from first principles modeling. One of the objectives of this paper is to solve the optimal lift gas distribution problem using the Generalized Reduced Gradient (GRG) method. In addition, multi-start search routine is developed to ensure that the local optimal solution is closer to the global solution. Sensitivity of the optimal solution to changes in oil field parameters like reservoir pressure, Productivity Indices (PI), total lift gas supply (input disturbance) and separator pressure is studied. It is shown that the available lift gas is distributed among the wells according to the PI values of the wells and the optimal values are highly sensitive to the changes in PI values. A self-optimizing control structure using simple controllers is designed which is capable of keeping the oil field in optimal operating conditions without having to re-optimize the whole process when the input disturbance occur in the system. The simulation results show that the outcome of optimization is increased total oil production which leads to increased profit.

Valve Lift Profile Development and Optimization Using Matlab

Valve Lift Profile Development and Optimization Using Matlab

Lift generation with optimal elastic pitching for a flapping plate

AbstractThe lift-generating capabilities of a translating and passively pitching rectangular plate are assessed experimentally. The plate pitch dynamics are generated by a rotational spring, and a genetic algorithm isolates a set of spring parameters maximizing the average lift. Our experiments identified a range of parameters that produce kinematic trajectories associated with optimal lift production. The stroke length and the dynamic response of the spring at the driving frequency are revealed to play crucial roles in the generation of such trajectories. Measurements taken with digital particle image velocimetry are used to analyse the results.

The application of downhole gas compression to improve productivity for depleted natural gas reservoirs

Selection of an optimal artificial lift technology to prolong a depleted gas reservoir has always been a challenge in the oil and gas industry. To be able to have a solution that has low intervention costs and a long operating life is the key. Downhole gas compression (DGC) is the new form of artificial lift technology specifically designed, for gas wells, to increase productivity and maximise the recovery factor of the reservoir. DGC would provide a 20–40% production gain anytime during the production life-cycle of the well. Numerous challenges, however, associated with the design, development and implementation of this new technology are not well understood or documented. Thus, this study has been focused on understanding the key concepts of DGC technology and investigates its potential application for increasing the well productivity of gas wells through sensitivity studies. Emphases are given on the development of a mathematical model that can be used to investigate the effect of reservoir and well operating conditions with the production gain of DGC. This peer-reviewed paper presents the results of some case studies, identifying the key factors associated with the operating condition, well completion, and reservoir properties considered for the successful deployment of such an alternate form of artificial lift method for a gas well based on sensitivity analysis using a developed mathematical model. The sensitivity results confirm a significant gain of well productivity using DGC for certain reservoir and operating conditions.

Experimental Development of Low Flow Rate Pressure Feed System and Design of Installation for Analysis of Work Process in Hydrogen Synthesis Power Systems on Powder Aluminium

Installation is designed for experimental development of pressure feed system of low consumption (1-10 g/s) of powder metal (including aluminum powder brands ASD, PAP, PAD) to combustion zone of combustion chamber. It allows choosing optimal lift gas for powder metal fluidization, calibrating powder gas suspension flow measurement fitting and minimizing lift gas expenditure in powder metal flow using drum-type gas counter GSB-400.

Gas Lift Optimization Using Proxy Functions in Reservoir Simulation

Summary Artificial lift by means of gas injection into production wells or risers is frequently used to increase hydrocarbon production, especially when reservoir pressure declines. We propose an efficient optimization scheme that finds the optimal distribution of the available gas lift gas to maximize an objective function subject to surface-pipeline-network rate and pressure constraints. This procedure is a nonlinearly constrained optimization problem solved by the generalized reduced-gradient (GRG) method. The values of objective function, constraint functions, and derivatives needed for optimization can be evaluated through two methods. The first method repeatedly solves the full-network equations using Newton iteration, which takes into account the flow interactions among wells; however, this method can be computationally expensive. The second and more efficient method is a new approach proposed in this paper. It constructs a set of proxy functions that approximates the objective function and constraints as functions of gas lift rates. The proxy functions are obtained by solving part of the network that consists of a gas lifted well or riser, assuming a stable pressure at the terminal node where the partial network is decoupled from the rest of the network, and are used to inexpensively evaluate the objective function, constraints, and necessary derivatives for the optimizer. A procedure to predict the proxy functions on the basis of previous values can be used to reduce the number of partial-network solves, and the partial-network solution has been parallelized for faster simulation. These two methods can be applied at different timesteps during the course of the simulation. The proposed methods are implemented within a general-purpose black-oil and compositional reservoir simulator and have been applied to real-field cases.

Drag Reduction Methodology for Adaptive Tailless Aircraft

An approach is presented for determining optimum lift distributions for adaptive tailless aircraft. In this study, wing adaptation is achieved using multiple trailing-edge flaps that are used to optimally distribute the lift of the wing such that drag is minimized. For tailless aircraft that are stable in pitch, the lack of a secondary lifting surface makes it necessary that the lift distribution on the wing also satisfies a pitching-moment constraint to ensure trim. The current work implements a numerical approach that solves for the optimal scheduling of multiple trailing-edge flaps on the wing of a tailless aircraft for various flight conditions with a pitching-moment constraint to reduce both induced and profile drag. The approach uses superposition to construct the spanwise lift distribution from basic and additional loadings, and decomposes the flap-angle distribution into mean and variation distributions. Together, these elements enable the solution of the problem using semi-analytical methods that also provide insight. The results are presented for a planar, swept, tapered wing with two airfoil-section choices to verify the theory and provide insight for trade studies.

Production system analysis for Woollybutt mature oil field using dynamic simulation

This paper describes how multi-phase flow dynamic simulation techniques were applied to support and optimise the day to day production operations for the Woollybutt oil field on the North West Shelf, Australia. Eni Australia is the operator of the: Woollybutt oil project, which consists of two separate fields; Woollybutt North, which has three production wells; and Woollybutt South, which has one production well– Woollybutt–4H (WBT–4H). WBT–4H is located about 7 km from the floating production storage and offloading (FPSO) facilities and shares the production flowline with two other production wells from the Woollybutt North field. Production from WBT-4H accounts for more than 60% of the total production. For this reason, achieving steady production from this well is the highest priority for the operations. To understand the hydrodynamic behaviour and to maximise production from WBT–4H, the production system for the Woollybutt South field was modelled from WBT–4H reservoir inflow points to the FPSO using a commercial dynamic simulation software package. The model successfully matched the pressures measured at the permanent down hole gauge (PDHG) and upstream production subsea choke dynamically, using the arrival pressure at the FPSO and the measured gas lift rate at the FPSO as input data. The model was used to identify the reason for slugging , to locate where the slugging conditions were originating, as well as to investigate optimum gas lift rate and the impact of bringing other wells on production from the Woollybutt South field. Furthermore, the model was used to identify the cause of sudden severe slugging, which forced to reduce the subsea production choke opening. The simulation work concluded that an unstable gas injection at the gas lift orifice valve (GLOV) induced severe slugging. This conclusion was validated operationally in the field soon after. Results of the multi-phase flow dynamic simulation provided good understanding of the hydrodynamic behaviour in the production system and are used to make informed decisions to support and optimise the day to day production operations.

Research on Optimal Heat Sink Temperature Lift of Inverter Heat Pumps

Research on Optimal Heat Sink Temperature Lift of Inverter Heat Pumps

An investigation into the effects of unsteady parameters on the aerodynamics of a low Reynolds number pitching airfoil

The growing applications of low Reynolds number (LRN) operating vehicles impose the need for accurate LRN flow solutions. These applications usually involve complex unsteady phenomena, which depend on the kinematics of the vehicle such as pitching, plunging, and flapping of a wing. The objective of the present study is to address the issues related to LRN aerodynamics of a harmonically pitching NACA0012 airfoil. To this end, the influence of unsteady parameters, namely, amplitude of oscillation, d, reduced frequency, k, and Reynolds number, Re, on the aerodynamic performance of the model is investigated. Computational fluid dynamics (CFD) is utilized to solve Navier–Stokes (N–S) equations discretized based on the Finite Volume Method (FVM). The resulting instantaneous lift coefficients are compared with analytical data from Theodorsen’s method. The simulation results reveal that d, k, and Re are of great importance in the aerodynamic performance of the system, as they affect the maximum lift coefficients, hysteresis loops, strength, and number of the generated vortices within the harmonic motion, and the extent of the so-called figure-of-eight phenomenon region. Thus, achieving the optimum lift coefficients demands a careful selection of these parameters.

Optimal lift force coefficient databases from riser experiments

Significant past effort has gone into understanding the complicated flow–structure interaction problem of vortex-induced vibration (VIV) of long flexible cylindrical structures (e.g., risers, mooring lines, tendons, conductors) in the ocean environment. However, major challenges persist with regard to riser VIV modeling and response prediction. The existing prediction schemes are based on a number of hypotheses, experimental facts and data like strip theory, energy balance, correlation length and, most importantly, the use of lift force coefficient databases. Recent advances in observing the VIV motions on experimental risers with high confidence shows that some of these assumptions may not be valid. One important source of the discrepancies between theoretical estimates and experimental observations arise from the use of experimentally obtained lift coefficient databases. These databases were obtained under the laboratory conditions of limited Reynolds number , and under the assumption that the cross-flow motions are not influenced by restraining the in-line motions. In this paper we develop a method to improve the modeling capability of riser VIV by extracting empirical lift coefficient databases from field riser VIV measurements. The existing laboratory-based lift coefficient databases are represented in a flexible parameterized form using a set of carefully chosen parameters. Extraction of the lift coefficient parameters is posed as an optimization problem, where the objective is to minimize the error between the prediction using a theoretical model and the experimental data. Application of the method to data from the Norwegian Deepwater Programme experiments shows that the new optimal databases significantly reduce the error in estimating the riser VIV cross-flow response.