e-petroleumservices.com 1 Online Field-Wide Gas-lift Optimisation Dr Alasdair S Brown Technical Manager EPS Americas Inc

e-petroleumservices.com 2 Presentation Structure Introduction Single Well vs Field Wide Online vs Offline Case Studies –Latin America –Middle East Conclusions Questions

e-petroleumservices.com 3 Single Well Single Well Gas Lift Optimisation –Valve Spacing –Injection Depth –Valve Performance –GL Injection Pressure –Q gaslift –CHP

e-petroleumservices.com 4 Single Well Conditions change –GL is inherently flexible –Design in flexibility Single well optimum –Well performance curve –Different for each well –Not necessary optimal for system

e-petroleumservices.com 5 Gas Lift Optimisation Gas Lift Compressor Well Equal Gradients Method Common Pressure

e-petroleumservices.com 6 Field Wide Optimisation Field Wide Gas Lift Optimisation –Distribution of Gas to competing wells –Pressure losses in gas lift distribution system –Pressure losses in production system –“Closing the Loop” Total system modellingTotal system modelling –including produced gas reinjection –Compressor performance –Offline/Online

e-petroleumservices.com 7 Why Online? Large Number of Wells Complex optimisation problem Reduce cycle time –Optimisation-to-implementation –Engineer’s time concentrated on value adding tasks Goals –Automate Process –Automate Repetitive Tasks –Optimise

e-petroleumservices.com 8 Sustainable Production Optimisation Time Increased Value Over ‘Do Nothing’ Simple Manual Optimisation Complex Manual Optimisation (Offline GLO) Complex Automated Optimisation (Online GLO)

e-petroleumservices.com 9 Automation & Optimisation Off-line –Data input manually into system model –Results from system model implemented manually Open loop –Data input automatically into model from SCADA –Results from model implemented manually Closed loop –Data input automatically into model from SCADA –Results from model implemented automatically via set point controllers –Operator review may be required to ensure that implemented results are “sensible”

e-petroleumservices.com 10 Off-line Optimisation Optimiser Field OPERATOR Advice Approval Implementation Manual Data Input Data Output

e-petroleumservices.com 11 Open Loop Optimisation Optimiser Field OPERATOR Advice Approval Implementation Automatic Data Input Data Output

e-petroleumservices.com 12 Closed Loop Optimisation Optimiser Field OPERATOR Advice Approval Implementation Automatic Data Input Data Output Setpoint Controllers

e-petroleumservices.com 13 Case 1: PdVSA On-Line –SCADA data automatically loaded to give current block valve and compressor status and to constrain the optimisation to stay close to existing operating conditions –Price/cost and equipment constraint data loaded from Corporate databases –Gas injection well set-points sent directly to SCADA controllers (after production operator review as a block) –Recommended pressure control valve set-points and compressor operating conditions sent to production operators in open-loop advisory messages –Results stored in central database for access by other applications.

e-petroleumservices.com 14 PdVSA Systems Overview PROCESS CONTROL CENTRAL CONTROL OPTIMISATION CIS RTU, PLC.. SCADA ASMS, WTO, NN, OM&S, IS CENTINELA, SIAL, SICOT..

e-petroleumservices.com 15 Integration Schematic

e-petroleumservices.com 16 System Architecture

e-petroleumservices.com 17 Process Control Central Control Optimisation Corporate Systems PdVSA Online GLO GLO

e-petroleumservices.com 18 Process Control Central Control Optimisation Corporate Systems The Online GLO Application RTU/PLC Optimiser Database SCADA Input Output Input Output

e-petroleumservices.com 19 Online GLO Daily Operation GLO GLO is executed... Gas lift rates and recommendations download to SCADA Gas Lift Well Mini Plantas Compressors The results are evaluated... Approval at Supervisory level The SCADA Operator accepts the gas lift rates and carries out adjustments

e-petroleumservices.com 20 The Optimisation Problem Fuel, Q gc Formation Gas, Q gf Produced Gas = Q gf +Q gi Other uses = Q gf - Q gc Lift Gas, Q gi Oil + Water +$-$ +$ CHP Qoil Gas Injection Rate Gas-lifted Wells (Curves for one WHP) Compressors Qsuction Pdisch Stonewall Surge

e-petroleumservices.com 21 Optimisation Overview From Other Flow Stations Flow Station Compressor Turbine Power Flare Low Pressure Gas Gathering Network Export High Pressure Gas Injection Network To Other Wells Oil + Water Lift Gas Manifold FlowGroup

e-petroleumservices.com 22 La Salina Online Tuned Well Models Generate Operating Pt Wellhead Performance Curve Wells in Flowgroups Flowgroup Performance Surfaces HP Gas Lift Network LP Gas Gathering Network Complete Network

e-petroleumservices.com 23 Field Implementation Results

e-petroleumservices.com 24 ICP Schematic CDMS SCADA GLO ICP GUI GLO DLL ON_LINE GLO Application OFF_LINE GLO Project Database ON_LINE GLO Project Database MASTER_MODEL GLO Project Database Date Stamped T UXE D OT UXE D O GLO ICP Copy (on Completion) Copy Optimize View Update Optimize Load Extract Load Extract View & Accept or Reject Results Extract Start On-Line Off-Line Routine On-Line Run

e-petroleumservices.com 25 POIS POIS = Production Operation Information System Northern fields of Kuwait Performed by consortium including EPS, Aspentech, Daelim EPS role was to provide the optimization software, software integration and detailed engineering models for five fields in North Kuwait. The fields included 197 wells (411 well strings) –33 water injectors, –91 gas lifted producers and –30 produced with ESPs. The wells and fields are connected through a complex network allowing wells to be switched between high, medium and low pressure as well as ‘wet’ and ‘dry’ separator trains Total production 600 Mstb/day

e-petroleumservices.com 26 Design Brief Hydraulic model of GL Distribution System Compressor Station behaviour and Performance –Power turbines, compression, gearboxes, intercoolers, gas recycling –Surge and stonewall constraints Multiphase Flow Scalable to >1000 wells Optimise non-hierarchical networks Online Integration with –Production Management System –DCS/SCADA System

e-petroleumservices.com 27 Objectives Data acquisition via SCADA to MIS (Aspentech) GL optimisation for new GL wells –GL being installed following water injection Automatic acquisition of WT data Automatic well model recalibration Automatic online GL optimisation calculation Manual setting of optimised setpoints (initially)

e-petroleumservices.com 28 PAS Concept PAS New Well Test WellFlo Well Model Compare with trend Engineer intervention Rerun or retune POIS Fail Pass Manual Model Retune Automatic Model Retune Rerun Welltest Data Transfer Past data

e-petroleumservices.com 29 GLO Concept GLO ReO System Model POIS Network model Wells Initiate GLO run Get Updated well models Generate well performance Run GLO Convert to choke settings New Settings New gas allocation

e-petroleumservices.com 30 Implementation Well modelling of all 411 wells (WellFlo) Construction and tuning of network Model (ReO) Automatic tuning of Well models Automatic GL optimisation Integration with Aspentech MIS Model maintenance and development

e-petroleumservices.com 31 Important Issues Identified Data Quality –Well data –production data –Surface network data Business processes –building use of POIS model into std. procedures –model maintenance –model enhancement Compressor optimisation Multistage separation optimisation

e-petroleumservices.com 32 Network Config Modelling Individual fields (viz., RA, SA, RQ, AD & BH) modelled as separate sub-sheets Each GC has 7 headers that can take inflow from any or all wells All fields interconnected through 3 Gathering Centres: GC-15, GC-23, and GC-25

e-petroleumservices.com 33 Network Config Modelling Multiple GC & MF options for all the wells made network very flexible to accommodate any future flow path definition Optimiser easily handled this huge network - over 40,000 objects!

e-petroleumservices.com 34 SCADA & POIS Well Head Pressure From 217 Wells GC SCADAGC DCS GC RTDB (POIS) All DCS DATA TRANSFERRED RADIO LINK PMDB ALTAMEER (POIS) FINDER WELL INFORMATION Business Process Explorer GUI WellFlo Reo & WellFlo Maintain Well Models (Administration of) PAS Hydrocarbon Accounting Material Balance GLO User

e-petroleumservices.com 35 Top Level Network

e-petroleumservices.com 36 Abdali: 16 Wells to 2 GC via 13 6in lines Ratqa: 20 Wells to 2 GC via 36in & 10in lines Raudhatain: 195 Wells to 3 GC thru’ 7 MF each Sabriyah: 142 Wells to 1 GC thru’ 7 MF Bahra: 5 Wells to 1 GC thru’ 7 MF 378 producers with choice of producing into any of 3 GCs through any of 21 MFs Network Config Modelling

e-petroleumservices.com 37 RA Field Network

e-petroleumservices.com 38 Lift-Gas System 5x7 Possible inputs from RQ & AD fields 9 Sub-sheets holding wells each 7x3 MF interconnecting all 194 wells across the field 7x3 MF outlets to production terminals Lift gas to SA field Network Config Modelling

e-petroleumservices.com 39 NP & GLwells (FG) Multi-header choice for lift-gas at present & for future Multi-MF choice for production at present and for future Network Config Modelling

e-petroleumservices.com 40 GL Well Performance Surface Data

e-petroleumservices.com 41 Conclusions KOC currently producing to quota –Current capacity higher than quota (how much higher is unknown) –However additional production can be allocated to NK –Cost reduction is additional benefit Reduction in admin overhead Reduction in flaring Potential reduction in new well requirement Network reconfiguration Work practices need to change to extract full value from the system

e-petroleumservices.com 42 POIS project Client - Kuwait Oil Company Year of Contract Award – 2000 Projected Value Generated: –$100 million - $175 million per annum (projected)

e-petroleumservices.com 43 Questions?