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Petroleum Experts Ltd. Janvier Lissanon. Gas Lift Optimization Workshop. Gas Lift Design for a single Well Understanding individual well performance Optimized gas lift allocation in a multi-well system. Gas-Lift Objectives. Maximize the oil production today and tomorrow
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Gas Lift Optimization Workshop Gas Lift Design for a single Well Understanding individual well performance Optimized gas lift allocation in a multi-well system
Gas-Lift Objectives • Maximize the oil production today and tomorrow • Systematic Analysis of individual production system components (well, fluid description, reservoir response, valve response, pipe line behaviour) • Allocate the available gas lift volume in a multi-well system by taking into account the entire network response: a non-linear optimization problem
Gas-Lift Design: Objectives • Optimized Gas Lift Design for individual wells: • Finding the optimum design rate per well • Finding the required gas lift gas injection rate and injection depths • Finding unloading valves depths, valve trim sizes and dome setting pressures • Ensuring required design flexibility to changing operating conditions • Check of third party Design (Existing mandrels)
Gas Lift Optimisation in a multi-well system • Gas Lift is to be allocated in order to maximise oil production • Wells, Pipelines and overall System constraints are to be honoured • Impact of network response on individual well performance is to be accounted for
Liquid Rate Gas Injection Rate Liquid rate Gas Injection rate Multi-Well System
Optimization Techniques in a multi-well system • The “Equal Slope” Method • Linear Programming • The Sequential Quadratic Programming technique
Starting Point 100 First Calculation 200 Convergence 300 GL#1: Actual well Response Q True Response Gas Lift Gas
SQP Response Comparison EQ-SLP-LP-SQP Q ∆QOil ES – LP - SLP ∆Q Gas Inj Gas Lift Gas
CRITERIAS FOR A SUCCESSFUL OPTIMIZATION • Wells PC must have the network feedback embedded in their expression (1st and 2nd Derivative) • Ability to respect constraints by realistic means • Ability to handle mixed systems (NF wells, ESP-wells, gas lifted wells) • SQP: • non-linear optimization method which accounts for the entire network response: GAP
VARIOUS OPTIMIZATION TECHNIQUES • Equal Slope: • works only if no pipeline response is to be accounted for • cannot handle constraints in optimized fashion • LP/SLP: • can handle constraints but • can not optimize non-linear systems like gas lifted systems • SQP: • Optimization method for Gas Lift Allocation accounting for the entire network response
SUMMARY • Solid, Consistent and Flexible Gas Lift Design using PROSPER • Ability to analyse, troubleshoot and quantify the benefit of work-over using PROSPER • Optimize the gas lift allocation in a multi-well system with an optimizer which accounts for the entire network response: GAP